太阳能光伏电池论文中英文资料对照外文翻译文献综述

附录AMicroprocessor-Controlled New Class of OptimalBattery Chargers for Photovoltaic ApplicationsAbstractA simple, fast and reliable technique for charging batteries by solar arrays is proposed. The operating point of a battery is carefully for cednear the maximum power point of solar cells under all environmental (e.g., insolation, temperature, degradation) conditions. Optimal operation of solar arrays is achieved using the V oltage-Based Maximum Power Point Tracking (VMPPT) technique and the charger operating point is continuously adjusted by changing the charging current. An optimal solar battery charger is designed, simulated and constructed. Experimental and the oretical results are presented and analyzed. The main advantages of the proposed solar battery charger as compared with conventional ones are shorter charge time and lower cost.Index Terms—Charger, microprocessor, maximum power point tracking (MPPT), photovoltaic.I.INTRODUCTIONThe field of photovoltaic systems is quite broad with many stand-alone and grid-connected configurations. Applications of solar energy include water pumping , refrigeration and vaccine storage, air conditioning, light sources, electric vehicles ,PV power plants ,hybrid systems , military and space applications.Reference[8]has divided photovoltaic applications into four categories: large-scale grid connected systems, small remote photovoltaic plants, low power stand-alone systems, and a combination of solar systems with other alternative energy sources. These categories may also be viewed in terms of load characteristics. There are three load types:a DC load, a “dead” AC load, and a “live” AC load(e.g.,a utility system).Most of these applications use batteries as backup energy systems and/or matchingdevices for balancing their energy flow during peak load or poor environmental conditions (e.g., low insolation, high temperature or high degradation).The main drawbacks of PV systems are high fabrication cost, low energy conversion efficiency, and nonlinear characteristics. For increasing conversion efficiency, many Maximum Power Point Tracking (MPPT) techniques have been proposed and implemented. They can be categorized as:A)“Look-up table”methods [12],[13]—The nonlinear and time varying nature of solar cells and their great dependency on radiation and temperature levels as well as degradation(aging,dirt,snow) effects, make it difficult to record and store all possible system conditions.B)“Perturbation and observation(P&O)”methods [14],[15] —Measured cellcharacteristics (current, voltage and power)are employed along with an on-line search algorithm to compute the corresponding maximum power point which is dependent on insolation, temperature or degradation levels. Problems with this approach are undesirable measurement errors(especially for current)which strongly affect tracker accuracy.C)“Computational” methods [2],[16]–[19]—The nonlinear V-I haracteristics of a solar panel are modeled using mathematical equations or numerical approximations, and maximum power points are computed for different load conditions as a function of cell open-circuit voltages or cell short-circuit currents. In the literature, many battery charging techniques are investigated and proposed[20]–[24].These methods use avariety of battery characteristics(voltage and temperature) to achieve a safe and fast charging process. However, two well-known charging methods employing photovoltaic sources are the constant current charging, and the direct connection of solar panel to battery and load(e.g., battery tied solar systems).In this paper, a simple and fast variable-current charging tech-nique, based on “computational” methods, is proposed for photovoltaic applications —where photovoltaic charger and battery are matched with respect to voltage and current. Online measurements of panel open-circuit voltage are used to detect the maximum power point of a solar panel. Battery charge rate is continuously adjusted such that the system operating point is forced near the detected maximum power point of solar panels. The oretical and experimental analyses are used to demonstrate the reliability and validity of the proposed technique.II.MODELING OF PROPOSED FAST SOLARBATTERY CHARGERElectrical models for solar panel, maximum power point tracker, battery and battery charger will be used to simulate the proposed solar charging technique.A.Solar Panel ModelUsing the equivalent circuit of solar cells(Fig.1),the radiation and temperature dependent V-I haracteristics of m parallel strings with n series cells per string is00()sc sa sa s sa I i mI nn V In R i mI mλ-+=- （1） where is the cell short-circuit current(representing in solation level), is the reverse saturation current,is the series cell resistance and is a constant coefficient which depends on the cell material and the temperature T.For the silicon solar panel(,)used for theoretical and experimental analyses of this paper[Table I, manufactured by the Iranian Optical Fiber Fabrication Co.(OFFC)],(1)can be written as at T=250.000051.767()0.00005sc sa sa sa I i V In i -+=- （2） Equations(3a)and(3b)are evaluated for one OFFC panel at T=70 and T=-20, respectively. Computed and measured V-I as well as P-I characteristics for the OFFCpanel are shown in Fig.2 for two insolation levels. This figure illustrates the variations of cell maximum power points (e.g., maxima of P-I curves)with respect to insolation levels.3.0050.000241.69()0.00024sa sa sa i V In i -+=- (3a) 20830.000011.82()0.00001sa sa sa i V In i -+=- (3b) Eqs.(2)and(3)along with Fig.2 depict the strong nonlinear dependency of the Maximum Power Point(MPP)with respect to insolation and temperature levels and justify for any high efficient PV system an accurate MPP tracker.B.V oltage-Based Maximum Power Point Tracking to determine operating points corresponding to maximum power for different insolation and temperature levels,(2)and(3) are commonly used[2],[17]to compute the partial derivative ofpower with respect to cell voltage.Instead of finding the maximum via derivative,[18]and[19]employ numerical methods to show a linear dependency between “cell v oltages corresponding to maximum power ”and“ cell open circuit voltages”MP v OC V M V = (4)This equation characterizes the main idea of the V oltage-Based Maximum Power Point Tracking (VMPPT) technique. Is called the“voltage factor”and is equal to 0.74 for the OFFC silicon cells[18],[19].Equation(4)is plotted in Fig.3 together with the computed(almost linear)dependency of with respect to(shown by “+” signs ). C. Nonlinear Battery Model Most battery models ignore the presence of nonlinear electro chemical characteristics[27],[28].For the theoretical and experimental analyses of this paper, we propose a new nonlinear model for Ni-Cd batteries as shown in Fig.4. Measurements show linear variations of, and nonlinear characteristics of with respect to charge rate: （5）where is the charging current and R , Cs and Co are parameter values at biasing current level. For one cell of the 7 Ah Ni-Cd battery used for theoretical and experimental analyzes of this paper, the constants of(5)are obtained from measured characteristics(Table II)at charge rates of,and C. Computed and measured battery characteristics are compared in Fig.5. D.The Proposed Solar Charger For the optimal solar charger,an appropriate combination of the MPPT algorithm and battery charging technique must be selected. For the tracker, the simple and reliable voltage-based MPPT technique is used requiring very few components for sensing the solar-panel, open-circuit voltage. For the charging technique, variable-current charging is selected. This will allow the tracker to continuously adjust battery-charging rate and force the system operating point near the maximum power point of solar panels. Other tracking 1232123()()()()()()())lin s bat so rs bat o lin s bat so cs bat o lin P bat po cp bat o nonlin p bat p bat p bat p R f I R K I I C f I C K I I C f I C K I I R f I K I K I K ==+-==+-==+-==++techniques could also be used. However, they require more components(for sensing panel short-circuit current and/or simultaneous panel voltage and current measurements)resulting in lower overall efficiency.III.SIMULATION OF PROPOSED SOLARBATTERY CHARGERSimulink software and its facilities are used to model the proposed solar battery charger(Fig.6).We have created a block called“PV Source”to simulate the nonlinear V-I characteristics of one OFFC solar panel(2)employing cell short-circuit current as a measure of insolation level [Fig.6(b)].Saturation and delay functions are introduced to limit the fast response of the “controlled voltage source”and to improve convergence. The output of this block is the panel operating voltage.To simulate voltage-based maximum power point tracking, a block called “VMPPT”is introduced[Fig.6(c)]that usesand to generate desired duty cycles for the charge unit.The panel open-circuit voltage is calculated,thereafter the panel voltage corresponding to maximum power(4)is computed and compared with and the error is amplified through a proper transfer function to generate the desired duty cycle.The charger unit consists of a DC/DC buck converter(chopper and output filter)and a LC input filter. The chopper includes a fast switch and a schottky diode. A block called“B attery Parameter Calculation”computes battery parameters [Fig.4 and(5)]corresponding to the system operating point.IV.CONSTRUCTION OF PROPOSED SOLARBATTERY CHARGERFig.7 shows the constructed battery charger, which consists of the following parts:Silicon Solar Panel—one OFFC silicon solar panel with maximum output power of about 35 W(Table I)is used togenerate solar energy. Microprocessor—The 8085 Micro Controller Unit(MCU)is used to record and process measured voltage and current waveforms and to compute required signalsfor control and drive circuits. The 1524 IC employed to generate the required PWM command(e.g.,at 50 kHz)and voltage/current signals for the charger unit. Thevoltage-based MPPT for the solar panel is implemented by MCU under different environmental and output operating conditions. Note that the panel open-circuit voltage is continuously measured at a slower rate (e.g., every minute).Fig.8 shows the main functions of the MCU. If multiple solar panels with similar characteristics are used, a reference panel could be relied on to sense the open-circuit voltage. Any shadowing effects caused by dust, snow or clouds will result in power-current characteristics with several maxima. This will complicate MPPT.Charger Unit—A chopper circuit is used to properlyconnect anddisconnect—based on PWM signals—solarpanel from battery and load. Input and output filters are employed to suppress electrical noise at the output of the solar panel and at the input of the battery.Input and output current and voltage sensors are relied on for signal measurements.Battery and Load—Five units of 7 Ah Ni-Cd batteriesare connected in series to store electrical energy. Resistors serve as loads during discharging and charging modes, respectively. In discharge mode, the solar panel is partially or totally inactivated by shadow or eclipse effects.V.ANALYSIS OF EXPERIMENTAL ANDTHEORETICAL RESULTSThree charging methods are investigated: the proposed variable-current charging (method 1), direct connection of battery and load to solar panel(method 2),and constant-current charging(method 3). Battery (full) charging state is detected using the approach (e.g., using magnitude and slope of battery voltage as a function of time)of[24].Experiments are performed for the following three operating conditions.Case A:Operation at an Incidence Angle of about Measured and computed time functions for battery current and voltage as well as solar panel power and voltage are shown in Fig.9 for normal operating condition(e.g.,normal insolation and temperature).As expected,fine tracking of solar maximum output power is achieved throughout the charging process when the proposed charging technique is used[Fig.9(c)],method 1).Charging time for the proposed method is only 3 hours which is about 73%and 52%of the required charging times for methods 2 and 3,respectively. In method 1,panel voltage(corresponding to maximum power)which is determined by(4)is slightly higher at 11 A.M.due to lower environmental temperature.In method 2,panel voltage[e.g.,in Fig.9(d)]and its operating point is dominated by battery voltage.This causes panel output power to decrease from 29 W(for method 1)to about 20 W(for method 2).In method 3,panel voltage[about 17 V in Fig.9(d)]is determined by panel current which is proportional to the constant battery current (e.g.,0.2 C).This rate of charge is used to determine panel operating points for the simulation as outlined in Fig.6.The comparison of computed(X)and measured results forsome selected operating points is shown in Fig.9.Case B:Operation at an Incidence Angle of about Similar experiments are performed for a change in angle of incidence(Fig.10).At 12:30 P.M.the solar panel is rotated forward(in the direction of sun)such that the angle of incidence is changed from about to about. During the first 105 minutes, the charging processes of the three methods are normal and results are similar to Fig.9. At the start of changing the angle of incidence from about to about, maximum panel output power is decreased to about 25 W[Fig.10(c),method 1].Our detailed measurements show that under all operating conditions (e.g., before and after changing the angle of incidence),method 1 continues to adjust panel operating point near the maximum power point of the V-I characteristics. The angle of incidence of about increases charge time of method 1 toabout 3.2 h. Methods 2 and 3 are not able to completely charge the battery since their operating points are not optimally selected. Note the inherent small voltage regulation of method 1,caused by the increasing slope of battery voltage. This is not true for methods 2 and 3 where fast voltage drops [e.g., at 12:30 P.M. and 13:45 P.M.in Fig.10(b)]occur. The measured characteristics of method 3 are interesting: constant-current charging continues for some time after changing the angle of incidence from to,this is so because the battery requires about 20 W of power [Fig.9(c),method 3].At 13:45 P.M.,the solar panel is no longer able to produce the required power since its maximum power is decreased to about 20 W. The converter duty cycle is forced to unity, causing direct connection of panel, battery and load. Therefore, measured characteristics of methods 2 and 3 become similar.Case C: Operation with Eclipse This environmental operating condition is essential in satellite and spacecraft applications .Cease of insolation along with considerable temperature drop makes panel V-I characteristics very different before and after eclipse. We have generated this effect(Fig.11)by completely covering solar panel from 12:00 to 12:30 P.M. and decreasing its temperature from 24 C to 12 C As expected, charge time of proposed method is slightly increased to 2.8 h which is about 65%and 63%of the times required for methods 2 and 3,respectively. Note the increased panel maximum output power from 28 W(before eclipse)to 33 W(just after eclipse)due to temperature effects(Fig.11).The temperature drop does not change panel output power in method 2 because the panel operating point is dominated by the constant battery voltage. Similar analysis holds for method 3 where the panel operating point is mainly determined by constant panel current, caused by the constant battery current. Note that the stored energy in the battery[e.g.,] is not exactly equal for the three charging methods(Table III).This is due to different charging currents, which changes battery charging efficiency[29]VI.CONCLUSIONSV oltage-based maximum power point tracking and a nonlinear battery model are used to introduce a new class of microprocessor based optimal solar battery chargers.A photovoltaic system consisting of a silicon solar panel, charger unit,Ni-Cd batteries and a resistive load is constructed and simulated. Based on theoretical and experimental results which are performed for the proposed charging technique(method 1),the direct connection of solar panel to battery and load(method 2),and the constant current charging(method 3),the following conclusions are drawn:Computed results for selected operating points show good agreements with measurements.Under different operating conditions, the solar panel output powers are larger for the proposed charging technique(method 1)as compared to methods 2 and 3(e.g., 20%to 65%).Therefore, the proposed charging technique requires fewer solar panels(e.g., lower cost).The proposed charging technique is faster than methods 2 and 3(e.g.,40%to 75%shorter charging times)under different environmental conditions. Under low insolation condition(e.g., angle of incidence of about),charging time of proposedtechnique is increased by 20%while methods 2 and 3 fail to charge the battery since their operating points on panel V-I characteristics are not optimally selected.The battery stored energy for the proposed charger is less as compared to methods 2 and 3 due to the dependency of charging efficiency on the charge current[29]. The proposed charging technique does not introduce rapid voltage drops and establishes an inherent small voltage regulation, especially under unfavorable environmental conditions. Therefore, the proposed charging technique is suggested to replace unregulated photovoltaic systems.附录B一种基于单片机控制的新型光伏电池摘要本文提出了一种简单、快速可靠的太阳能电池阵列技术，使光伏电池在各种环境下（例如日照、温度等）都能接近最大功率点，理想的太阳能电池阵列工作点是通过基于最大功率点追踪技术（VMPPT）和控制工作点持续调节对改变的控制流改变来实现的。

5.1太阳能电池材料理论效率和要求最大的太阳能辐射转换为电能的效率索取已经研究很透彻。

这种效率可以由两种方法得到：热力学定理和热力学平衡[67]。

热机极限效率可以由卡诺关系η= 1 - （T2/T1）得出，其中T1是热源温度和T2为散热器温度。

太阳频谱可以近似为5900黑体辐射谱。

如果考虑边界条件，最高效率可以达到85％。

细致平衡原理是基于太阳能电池中不同的粒子通量平衡和因为热力学极限而产生的相似结果。

Shockley和Queisser的一篇重要论文中介绍到这一定理[68]。

现在，实际效率远低于理论限制。

其原因是可以从以下方面得到：——太阳光谱非常宽，范围从紫外到近红外，而半导体只能以特定效率转换具备带隙能量的光子。

光子能量较低不可以被吸收，高能量光子的能量因为载流子的热化减少到带隙能量。

现在可以使用几种串联细胞半导体改善这种情况，正如我们在（图5.3.1）看到的。

——阳光在到达地球表面的能量和它离开太阳的表面时相比，已经是非常少了。

直射的阳光通过特定方式积聚，可以得到更高的转换效率。

首先我们看本征半导体，并考虑它的最高效率。

在图看到5.1我们看到，带隙的效率曲线有最高点。

并且可以看出，硅是不是最大，但比较接近。

该书的一大部份是有关硅，虽然从固体物理学我们知道，硅光伏并非理想转换材料。

一个非常严重的问题是，半导体硅是一种非直接半导体;最高价带和最低导带在晶体空间彼此不是相反的，正如图2.1描述的那样。

图。

5.1。

依赖的带隙的半导体转换效率光吸收远在间接半导体弱于直接半导体。

从材料的角度看这是一个严重的问题：对于90％的光吸收，只需要1微米的GaAs（直接半导体）与100微米的硅。

载流子必须达到前表面附近的PN结。

对少数载流子扩散长度要为200μm，或至少达到两次硅的厚度。

因此，材料要非常高的纯度和高结晶程度。

鉴于这些物理限制，但令人惊讶的是硅在市场上却起到主导角色作用。

最主要的原因是，光伏到来之前，硅技术已已经高度发达，微电子市场中，优质材料正在大量生产，并且成本相对较低。

外文参考文献译文及原文目录外文文献译文 (1)1.中国光伏发电的战略地位 (1)2.世界光伏产业现状和发展预测 (2)3.中国光伏发电市场和产业现状 (3)4.中国光复发电的市场预测和规划建议 (5)5.结论 (6)外文文献原文 (7)1.China's strategic position PV (7)2.The world's current situation and development of photovoltaic industryforecast (9)3.The Chinese PV market and industry statu s (10)4.China's PV market forecasting and planning proposals (13)5.Conclusions (15)外文文献译文1、中国光伏发电的战略地位1.1 中国的能源资源和可再生能源现状和预测；无论从世界还是从中国来看，常规能源都是很有限的，中国的一次能源储量远远低于世界的平均水平，大约只有世界总储量的10％。

从长远来看，可再生能源将是未来人类的主要能源来源，因此世界上多数发达国家和部分发展中国家都十分重视可再生能源对未来能源供应的重要作用。

在新的可再生能源中，光伏发电和风力发电是发展最快的,世界各国都把太阳能光伏发电的商业化开发和利用作为重要的发展方向。

根据欧洲JRC 的预测，到2030年太阳能发电将在世界电力的供应中显现其重要作用，达到10%以上，可再生能源在总能源结构中占到30％；2050 年太阳能发电将占总能耗的20%，可再生能源占到50％以上，到本世纪末太阳能发电将在能源结构中起到主导作用。

我国政府重视可再生能源技术的发展，主要有水能、风能、生物质能、太阳能、地热能和海洋能等。

我国目前可再生能源的发展现状如下：水能：我国经济可开发的水能资源量为3.9 亿千瓦，年发电量1.7 万亿千瓦时，其中5 万千瓦及以下的小水电资源量为1.25 亿千瓦。

光伏发电介绍英文作文英文：As we all know, photovoltaic power generation, also known as solar power generation, is a method of generating electricity by converting solar energy into electrical energy using photovoltaic materials. The most common photovoltaic materials are solar cells, which are made of semiconductor materials such as silicon. When sunlight hits the solar cells, it excites the electrons in the material, creating an electric current that can be captured and used as electricity.One of the great things about photovoltaic power generation is its sustainability. Unlike fossil fuels, which are finite and contribute to pollution, solar energy is abundant and renewable. This means that we can continue to harness the power of the sun for electricity without depleting natural resources or harming the environment. In fact, many countries and regions are investing heavily insolar power as a clean and sustainable energy source.Another benefit of photovoltaic power generation is its versatility. Solar panels can be installed on a wide rangeof surfaces, from rooftops to open fields, making it a flexible option for generating electricity. In addition, solar panels can be used in both grid-connected and off-grid systems, providing power to remote areas that may not have access to traditional electricity sources.In my own experience, I have seen the impact of photovoltaic power generation firsthand. In my hometown, many households have installed solar panels on their roofsto generate electricity for their own use. This has notonly reduced their reliance on traditional power sources, but also saved them money on electricity bills. Furthermore, I have visited solar farms where vast fields of solarpanels are used to generate large amounts of electricityfor the local community. It's amazing to see how the powerof the sun can be harnessed to provide clean andsustainable energy for so many people.Overall, photovoltaic power generation is a promising and environmentally friendly method of generating electricity. With ongoing advancements in technology and increasing awareness of the importance of renewable energy, I believe that solar power will play an increasingly significant role in meeting our energy needs in the future.中文：众所周知，光伏发电，也被称为太阳能发电，是一种利用光伏材料将太阳能转换为电能的发电方法。

中英文资料对照外文翻译文献综述Design of a Lead-Acid Battery Charging and Protecting IC in Photovoltaic System1.IntroductionSolar energy as an inexhaustible, inexhaustible source of energy more and more attention. Solar power has become popular in many countries and regions, solar lighting has also been put into use in many cities in China. As a key part of the solar lighting, battery charging and protection is particularly important. Sealed maintenance-free lead-acid battery has a sealed, leak-free, pollution-free, maintenance-free, low-cost, reliable power supply during the entire life of the battery voltage is stable and no maintenance, the need for uninterrupted for the various types of has wide application in power electronic equipment, and portable instrumentation. Appropriate float voltage, in normal use (to prevent over-discharge, overcharge, over-current), maintenance-free lead-acid battery float life of up to 12 ~ 16 years float voltage deviation of 5% shorten the life of 1/2. Thus, the charge has a major impact on this type of battery life. Photovoltaic, battery does not need regular maintenance, the correct charge and reasonable protection, can effectively extend battery life. Charging and protection IC is the separation of the occupied area and the peripheral circuit complexity. Currently, the market has not yet real, charged with the protection function is integrated on a single chip. For this problem, design a set of battery charging and protection functions in one IC is very necessary.2.System design and considerationsThe system mainly includes two parts: the battery charger module and the protection module. Of great significance for the battery as standby power use of the occasion, It can ensure that the external power supply to the battery-powered, but also in the battery overcharge, over-current and an external power supply is disconnected the battery is to put the state to provide protection, the charge and protection rolled into one to make the circuit to simplify and reduce valuable product waste of resources. Figure 1 is a specific application of this Ic in the photovoltaic powergeneration system, but also the source of this design.Figure1 Photovoltaic circuit system block diagramMaintenance-free lead-acid battery life is usually the cycle life and float life factors affecting the life of the battery charge rate, discharge rate, and float voltage. Some manufacturers said that if the overcharge protection circuit, the charging rate can be achieved even more than 2C (C is the rated capacity of the battery), battery manufacturers recommend charging rate of C/20 ~ C/3. Battery voltage and temperature, the temperature is increased by 1 °C, single cell battery voltage drops 4 mV , negative temperature coefficient of -4 mV / ° C means that the battery float voltage. Ordinary charger for the best working condition at 25 °C; charge less than the ambient temperature of 0 °C; at 45 °C may shorten the battery life due to severe overcharge. To make the battery to extend the working life, have a certain understanding and analysis of the working status of the battery, in order to achieve the purpose of protection of the battery. Battery, there are four states: normal state, over-current state over the state of charge, over discharge state. However, due to the impact of the different discharge current over-capacity and lifetime of the battery is not the same, so the battery over discharge current detection should be treated separately. When the battery is charging the state a long time, would severely reduce the capacity of the battery and shorten battery life. When the battery is the time of discharge status exceeds the allotted time, the battery, the battery voltage is too low may not be able to recharge, making the battery life is lower.Based on the above, the charge on the life of maintenance-free lead-acid batteries have a significant impact, while the battery is always in good working condition, battery protection circuit must be able to detect the normal working condition of the battery and make the action the battery can never normal working state back to normal operation, in order to achieve the protection of the battery.3.Units modular design3.1The charging module Chip, charging module block diagram shown in Figure 2. The circuitry includes solar battery array Charge controller controller Discharge controller DC load accumulatorcurrent limiting, current sensing comparator, reference voltage source, under-voltage detection circuit, voltage sampling circuit and logic control circuit.Figure2 Charging module block diagramThe module contains a stand-alone limiting amplifier and voltage control circuit, it can control off-chip drive, 20 ~30 mA, provided by the drive output current can directly drive an external series of adjustment tube, so as to adjust the charger output voltage and current . V oltage and current detection comparator detects the battery charge status, and control the state of the input signal of the logic circuit. When the battery voltage or current is too low, the charge to start the comparator control the charging. Appliances into the trickle charge state when the cut-off of the drive, the comparator can output about 20 mA into the trickle charge current. Thus, when the battery short-circuit or reverse, the charger can only charge a small current, to avoid damage to the battery charging current is too large. This module constitutes a charging circuit charging process is divided into two charging status: high-current constant-current charge state, high-voltage charge status and low-voltage constant voltage floating state. The charging process from the constant current charging status, the constant charging current of the charger output in this state. And the charger continuously monitors the voltage across the battery pack, the battery power has been restored to 70% to 90% of the released capacity when the battery voltage reaches the switching voltage to charge conversion voltage Vsam charger moves to the state of charge. In this state, the charger output voltage is increased to overcharge pressure driverV oltage amplifierV oltage sampling comparatorStart amplifier State level control Charging indicator Logical module Undervoltage detection circuit R- powerCurrent sampling comparator Limiting amplifier Power indicatorV oc is due to the charger output voltage remains constant, so the charging current is a continuous decline. Current down to charge and suspend the current Ioct, the battery capacity has reached 100% of rated capacity, the charger output voltage drops to a lower float voltage VF.3.2 Protection ModuleChip block diagram of the internal protection circuit shown in Figure 3. The circuit includes control logic circuit, sampling circuit, overcharge detection circuit, over-discharge detection comparator, overcurrent detection comparator, load short-circuit detection circuit, level-shifting circuit and reference circuit (BGR).Figure3 Block diagram of battery protectionThis module constitutes a protection circuit shown in Figure 4. Under the chip supply voltage within the normal scope of work, and the VM pin voltage at the overcurrent detection voltage, the battery is in normal operation, the charge and discharge control of the chip high power end of the CO and DO are level, when the chip is in normal working mode. Larger when the battery discharge current will cause voltage rise of the VM pin at the VM pin voltage at above the current detection voltage Viov, then the battery is the current status, if this state to maintain the tiov overcurrent delay time, the chip ban on battery discharge, then the charge to control the end of CO is high, the discharge control side DO is low, the chip is in the current mode, general in order to play on the battery safer and more reasonable protection, the chip will battery over-discharge current to take over the discharge current delay time protection. The general rule is that the over-discharge current is larger, over the Sampling circuitOver discharge detection comparator Control logic circuitLevel conversion circuit Overcharge detection comparator Over-current detection comparator2 Over-current detection comparator1Over-current detection circuitLoad short detection circuitshorter the discharge current delay time. Above Overcharge detection voltage, the chip supply voltage (Vdd> Vcu), the battery is in overcharge state, this state is to maintain the corresponding overcharge delay time tcu chip will be prohibited from charging the battery, then discharge control end DO is high, and charging control terminal CO is low, the chip is in charging mode. When the supply voltage of the chip under the overdischarge detection voltage (Vdd <Vdl,), then the battery is discharged state, this state remains the overdischarge delay time tdl chip will be prohibited to discharge the battery at this time The charge control side CO is high, while the discharge control terminal DO is low, the chip is in discharge mode.ProtectionmoduleFigure4 Protection circuit application schematic diagram4.Circuit DesignTwo charge protection module structure diagram, the circuit can be divided into four parts: the power detection circuit (under-voltage detection circuit), part of the bias circuit (sampling circuit, the reference circuit and bias circuit), the comparator (including the overcharge detection /overdischarge detection comparator, over-current detection and load short-circuit detection circuit) and the logic control part.This paper describes the under-voltage detection circuit (Figure 5), and gives the bandgap reference circuit (Figure 6).Figure5 Under-voltage detection circuitFigure6 A reference power supply circuit diagramBattery charging, voltage stability is particularly important, undervoltage, overvoltage protection is essential, therefore integrated overvoltage, undervoltage protection circuit inside the chip, to improve power supply reliability and security. And protection circuit design should be simple, practical, here designed a CMOS process, the undervoltage protection circuit, this simple circuit structure, process and easy to implement and can be used as high-voltage power integrated circuits and other power protection circuit.Undervoltage protection circuit schematic shown in Figure 5, a total of five components: the bias circuit, reference voltage, the voltage divider circuit, differential amplifier, the output circuit. The circuit supply voltage is 10V; the M0, M1, M2, R0 is the offset portion of the circuit to provide bias to the post-stage circuit, the resistance, Ro, determine the circuit's operating point, the M0, M1, M2 form a current mirror; R1 M14 is the feedback loop of the undervoltage signal; the rest of the M3, M4 and M5, M6, M7, M8, M9, M10, M11, M12, M13, M14, composed of four amplification comparator; M15, DO, a reference voltage, the comparator input with the inverting Biasing circuit Reference circuit Bleeder circuit difference amplifier Output circuitAmplifierAmplifierinput is fixed (V+), partial pressure of the resistance R1, R2, R3, the input to the inverting input of the comparator, when the normal working of the power supply voltage, the inverting terminal of the voltage detection is lost to the inverting terminal voltage of the comparator is greater than V+. Comparator output is low, M14 cutoff, feedback circuit does not work; undervoltage occurs, the voltage divider of R1, R2, R3, reaction is more sensitive, lost to the inverting input voltage is less than V when the resistor divider, the comparator the output voltage is high, this signal will be M14 open, the voltage across R into M at both ends of the saturation voltage close to 0V, thereby further driving down the R1> R2, the partial pressure of the output voltage, the formation of the undervoltage positive feedback. Output, undervoltage lockout, and plays a protective role.5. Simulation results and analysisThe design of the circuit in CSMC 0.6 μm in digital CMOS process simulation and analysis of the circuit. In the overall simulation of the circuit, the main observation is that the protection module on the battery charge and discharge process by monitoring Vdd potential and Vm potential leaving chip CO side and DO-side changes accordingly. The simulation waveform diagram shown in Figure 7, the overall protection module with the battery voltage changes from the usual mode conversion into overcharge mode, and then return to normal working mode, and then into the discharge mode, and finally back to normal working mode. As the design in the early stages of the various parameters to be optimized, but to provide a preliminary simulation results.Figure7 Overvoltage and under-voltage protection circuit simulation waveform6.ConclusionDesigned a set of battery charging and protection functions in one IC. This design not only can reduce the product, they can reduce the peripheral circuit components. The circuit uses the low-power design. This project is underway to design optimization stage, a complete simulation can not meet the requirements, but also need to optimize the design of each module circuit.光伏系统中蓄电池的充电保护IC电路设计1.引言太阳能作为一种取之不尽、用之不竭的能源越来越受到重视。

文献信息：文献标题：A New Controller Scheme for Photovoltaics Power Generation Systems（光伏发电系统的一种新的控制方案）国外作者：Tamer T.N.Khatib，Azah Mohamed，Nowshad Amin文献出处：《European Journal of Scientific Research》,2009，Vol.33 No.3, pp515-524字数统计：英文1337单词，7006字符；中文2149汉字外文文献：A New Controller Scheme for Photovoltaics PowerGeneration SystemsAbstract:This paper presents a new controller scheme for photovoltaic (PV) power generation systems. The proposed PV controller scheme controls both the boost converter and the battery charger by using a microcontroller in order to extract maximum power from the PV array and control the charging process of the battery. The objective of the paper is to present a cost effective boost converter design and an improved maximum power point tracking algorithm for the PV system. A MATLAB based simulation model of the proposed standalone PV system has been developed to evaluate the feasibility of the system in ensuring maximum power point operation.1.IntroductionRecently, the installation of PV generation systems is rapidly growing due to concerns related to environment, global warming, energy security, technology improvements and decreasing costs. PV generation system is considered as a clean and environmentally-friendly source of energy. The main applications of PV systems are in either standalone or grid connected configurations. Standalone PV generationsystems are attractive as indispensable electricity source for remote areas. However, PV generation systems have two major problems which are related to low conversion efficiency of about 9 to 12 % especially in low irradiation conditions and the amount of electric power generated by PV arrays varies continuously with weather conditions. Therefore, many research works are done to increase the efficiency of the energy produced from the PV arrays.The solar cell V-I characteristics is nonlinear and varies with irradiation and temperature. But there is a unique point on the V-I and P-V curves, called as the maximum power point (MPP), at which at this point the PV system is said to operate with maximum efficiency and produces its maximum power output. The location of the MPP is not known but can be traced by either through calculation models or search algorithms. Thus, maximum power point tracking (MPPT) techniques are needed to maintain the PV array’s operating point at its MPP. Many MPPT techniques have been proposed in the literature in which the techniques vary in many aspects, including simplicity, convergence speed, hardware implementation and range of effectiveness. However, the most widely used MPPT technique is the perturbation and observation (P&O) method. This paper presents a simple MPPT algorithm which can be easily implemented and adopted for low cost PV applications. The objective of this paper is to design a novel PV controller scheme with improved MPPT method.The proposed standalone PV controller implementation takes into account mathematical model of each component as well as actual component specification. The dc–dc or boost converter is the front-end component connected between the PV array and the load. The conventional boost converter may cause serious reverse recovery problem and increase the rating of all devices. As a result, the conversion efficiency is degraded and the electromagnetic interference problem becomes severe under this situation. To increase the conversion efficiency, many modified step-up converter topologies have been investigated by several researchers. V oltage clamped techniques have been incorporated in the converter design to overcome the severe reverse-recovery problem of the output diodes. In this paper, focus is also given in the boost converter design. Another important component in the standalone PV systemsis the charge controller which is used to save the battery from possible damage due to over-charging and over-discharging. Studies showed that the life time of a battery can be degraded without using a charge controller.The proposed new controller scheme for the standalone PV system controls both the boost converter and the charge controller in two control steps. The first step is to control the boost converter so as to extract the maximum power point of the PV modules. Here, a high step-up converter is considered for the purpose of stepping up the PV voltage and consequently reducing the number of series-connected PV modules and to maintain a constant dc bus voltage. A microcontroller is used for data acquisition that gets PV module operating current and voltage and is also used to program the MPPT algorithm. The controller adopts the pulse width modulation (PWM) technique to increase the duty cycle of the generated pulses as the PV voltage decreases so as to obtain a stable output voltage and current close to the maximum power point. The second control step is to control the charge controller for the purpose of protecting the batteries. By controlling the charging current using the PWM technique and controlling the battery voltage during charging, voltages higher than the gassing voltage can be avoided.2.Design of the Proposed Photovoltaic SystemMost of the standalone PV systems operate in one mode only such that the PV system charges the battery which in turns supply power to the load. In this mode of operation, the life cycle time of the battery may be reduced due to continuous charging and discharging of the battery. The proposed standalone PV system as shown in terms of a block diagram in Figure 1 is designed to operate in two modes: PV system supplies power directly to loads and when the radiation goes down and the produced energy is not enough, the PV system will charge the battery which in turns supply power to the load. To manage these modes of operation, a controller is connected to the boost converter by observing the PV output power.3.MethodologyFor the purpose of estimating the mathematical models developed for the proposed standalone PV system, simulations were carried in terms of the MATLAB codes. Each PV module considered in the simulation has a rating of 80 Watt at 1000 W/m2, 21.2 V open circuit voltage, 5A short circuit current. The PV module is connected to a block of batteries with of sizing 60 Ah, 48 V.4.Results and DiscussionThe simulation results of the standalone PV system using a simple MPPT algorithm and an improved boost converter design are described in this section. Simulations were carried out for the PV system operating above 30o C ambient temperature and under different values of irradiation. Figure 9 shows the PV array I-V characteristic curve at various irradiation values. From the figure, it is observed that the PV current increase linearly as the irradiation value is increased. However, the PV voltage increases in logarithmic pattern as the irradiation increases. Figure 10 shows the PV array I-V characteristic curve at various temperature values. It is noted from the figure that, the PV voltage decreases as the ambient temperature is increased.Figure 4 compares the PV array P-V characteristics obtained from using the proposed MPPT algorithm and the classical MPPT P&O algorithm. From this figure, it can be seen that by using the proposed MPPT algorithm, the operating point of PV array is much closer to the MPP compared to the using the classical P&O algorithm.In addition, the proposed boost converter is able to give a stable output voltage as shown in Figure 5. In terms of PV array current, it can be seen from Figure 6 that the PV current is closer to the MPP current when using the improved MPPT algorithm. Thus, the track operating point is improved by using the proposed MPPT algorithm. In terms of efficiency of the standalone PV system which is calculated by dividing the load power with the maximum power of PV array, it is noted that the efficiency of the system is better with the proposed MPPT algorithm as compared to using the classical P&O algorithm as shown in Figure 7.5.ConclusionThis paper has presented an efficient standalone PV controller by incorporating an improved boost converter design and a new controller scheme which incorporates both a simple MPPT algorithm and a battery charging algorithm. The simulation results show that the PV controller using the simple MPPT algorithm has provided more power and better efficiency (91%) than the classical P&O algorithm. In addition, the proposed boost converter design gives a better converter efficiency of about 93%. Such a PV controller design can provide efficient and stable power supply for remote mobile applications.中文译文：光伏发电系统的一种新的控制方案摘要：本文提出了一种新的光伏（PV）发电系统控制器方案。

英文翻译Polycrystalline silicon solar cellsAs we all know, solar energy has many advantages, photovoltaic power generation will provide the main energy of mankind, but at present it, to make solar power a large market, is the general consumer acceptance, increased solar cell efficiency and reduce production costs should be our overriding goal, from the current development of the international solar cell can see the trend of its silicon, polycrystalline silicon, ribbon silicon, thin film materials (including trend of its silicon, polycrystalline silicon, ribbon silicon, thin film materials (including microcrystalline silicon thin films, compound-based thin film and dye film).From industrial development, it has been the focus of the direction of single crystal to polycrystalline, mainly due to;（1）the beginning and end of solar cell materials can supply less and less;（2）in terms of the solar cell, a square substrate is more cost-effective, by direct coagulation casting method and obtained direct access to a square polysilicon materials;（3）of polysilicon production technology continue to make progress, casting furnace automatic production cycle of each (50 hours) can produce over 200 kg ingots, grain size to achieve centimeter level;（4）in recent years as research and development of silicon technology quickly, in which technology has been applied to the production of polycrystalline silicon cells, such as selective etching the emitter, back surface field, corrosion suede , surface and bulk passivation, thin metal gate electrode, using screen-printing technology enables the gate electrode width down to 50 microns to 15 microns high, rapid thermal annealing technology for polysilicon production process can significantly shorten the time, single time of thermal process can be completed within a minute using this technology in the 100 square centimeters of silicon chip to make the cell conversion efficiency of over 14%. It was reported in 50 to 60 micron silicon substrate produced more than 16% cell efficiency.Mechanical groove, screen printing technology in polycrystalline on the efficiency of more than 17%, no mechanical groove in the same area on the efficiency of 16%, with buried gate structure, mechanical groove 130 on a square centimeter of polycrystalline cell efficiency of 15.8%.The following two aspects of the polysilicon to discuss battery technology.Laboratory efficient battery technology Laboratory techniques often do not consider the cost of battery production and mass production can only achieve maximum efficiency of the method and means to provide specific materials and processes that can achieve the limit.1.On the absorption of lightFor the optical absorption is mainly:(1)reduce the surface reflection;(2)Change the path of light in the cell body;(3)using the back reflection.For silicon, anisotropic chemical etching method applied in (100) surfaceproduced textured pyramid-shaped, lower surface light reflection. But silicon crystal to deviate from the (100) surface, using the above methods can not make even the suede, the current use of the following methods:（1）laser grooveGroove with a laser method can be produced in the polysilicon surface, inverted pyramid structure, in 500~900nm wavelength range, reflectance was 4 to 6%, with double-layer antireflection coating surface produced considerable. In the (100) reflection of silicon chemical production rate of 11% of the flock. Produced by laser textured surface than in the smooth double-layer antireflection coating film (ZnS/MgF2) short circuit current to increase by about 4%, mainly long-wave light (wavelength greater than 800nm) the reasons for slanting into the battery. Laser production of suede problems in etching, surface damage caused by the introduction of a number of impurities at the same time, through chemical treatment to remove surface damage layer. Solar cells made by this method are usually higher short circuit current, open circuit voltage is not high, mainly due to cell surface area increased, the recombination current increase.（2）Chemical grooveApplication of mask (Si3N4or SiO2) isotropic corrosion, etching solutions for acid etching solutions, but also for the higher concentration of sodium hydroxide or potassium hydroxide solution, the method can not create the kind formed by anisotropic etching cone-like structure. According to reports, the approach down the face of the formation of micron spectral range 700 to 1030 significantly reduced reflex. But the mask layer will be formed at higher temperatures, causing decreased performance polysilicon materials, especially for lower quality polycrystalline materials, reduce the minority carrier lifetime. Application of the technology made of polysilicon in cell conversion efficiency of 16.4%. Mask layer screen printing method can also be formed.（3）reactive ion corrosion (RIE)This method is a non-mask etching process, the formation of suede particularly low reflectivity in the spectral range 450 to 1000 micron reflectivity can be less than 2%. Only from the optical point of view, is an ideal method, but problem is serious silicon surface damage, the battery open circuit voltage and fill factor decreased.（4）produced antireflection filmFor efficient solar cells, the most common and most effective way is to double-layer antireflection coatings deposited ZnS/MgF2, its optimal thickness depends on the thickness of the oxide layer below the surface characteristics and battery, for example, the surface is smooth or textured surface，anti-reflection technology has evaporated Ta2O5, PECVD deposition Si3N3 so. ZnO conductive film can be used as anti-reflective material.2.MetallizationIn the efficient production of the battery, the metal electrode to the battery design parameters such as surface doping concentration, PN junction depth, the metal material to match. General area of small laboratory cell (area less than 4cm2), so they need small metal gate line (less than 10 microns), the general approach to lithography,electron beam evaporation, rge-scale production of industrial plating process is also used, but the combination of evaporation and lithography, do not belong to low-cost technology.3.PN junction formation technology（1）emitter formation and phosphorus getteringFor efficient solar cells, emitter diffusion formation of choice commonly used in the formation of heavy metal impurities in the region below the electrode in the spread between the electrodes to achieve light levels, the shallow emitter diffusion is increased concentration of cell response to blue light, and also allows silicon surface easily passivated. Two-step diffusion method diffusion process, diffusion process and increase corrosion buried diffusion process. Currently used selection proliferation, 15 × 15 cell conversion efficiency of 16.4%, n + +, n + sheet resistance of the surface region were 20Ω and 80Ω.For Mc-Si materials, expansion of phosphorus gettering effect on the battery has been widely studied, a longer period of phosphorus gettering process (usually 3 to 4 hours), make some of Mc-Si of the minority carrier diffusion length increase of two orders of magnitude.（2）the formation of back surface field and aluminum getteringIn Mc-Si cell, the back p + p junction by the formation of uniform diffusion of aluminum or boron, boron source is generally BN, BBr, APCVD SiO2: B2O8 such as evaporation or diffusion of aluminum screen printing of aluminum, 800 degrees completed sintering , on the role of aluminum gettering carried out extensive research, and in different phosphorus diffusion gettering, aluminum gettering at a relatively low temperature. Physical defects which also involved the dissolution and deposition of impurities, while in higher temperatures, the deposition of impurities easily dissolve into the silicon, on the Mc-Si have a negative impact. Far, to the regional background field has been applied to silicon solar cell technology, but in the polysilicon, the application of aluminum or the back surface field structure.（3）Double Mc-Si cellsMc-Si double the battery positive side for the conventional structure, on the back for the N + and P + cross-cutting structure, so that generated a positive light, but in the back of the photo birth rate near the back electrode can be effectively absorbed. Back electrode as an effective complement to the positive electrode, also planted as an independent flow of sub-collector on the back of the light and the scattered light to be effective, it was reported in the AM1.5 conditions, the conversion efficiency of over 19%.360毕业设计网4.Surface and bulk passivationFor Mc-Si, due to higher grain boundary exist, point defects (vacancies, interstitial atoms, metal impurities, oxygen and nitrogen and their compounds) and in vivo defect on the surface passivation is particularly important, in addition to the previously mentioned The gettering, the passivation process has a number of ways, by thermal oxidation to silicon dangling bonds saturated is a relatively common method, make Si-SiO2interface recombination velocity greatly decreased, the passivation effect depends on the launching area surfaceconcentration, the interface state density and the electron and hole cross sections were floating. Annealed in hydrogen atmosphere can passivation effect is more obvious. Nitride deposited by PECVD the recent positive is very effective because the process of film has the effect of hydrogenation. The process can also be applied to large scale production. Application of Remote PECVD Si3N4 surface recombination velocity is less than can 20cm / s.多晶硅太阳能电池众所周知，利用太阳能有许多优点，光伏发电将为人类提供主要的能源，但目前来讲，要使太阳能发电具有较大的市场，被广大的消费者接受，提高太阳电池的光电转换效率，降低生产成本应该是我们追求的最大目标，从目前国际太阳电池的发展过程可以看出其发展趋势为单晶硅、多晶硅、带状硅、薄膜材料（包括微晶硅基薄膜、化合物基薄膜及染料薄膜）。

翻译原文 (4)Photovoltaic (PV) Electric Systems (4)The Advantages of Mitsubishi Solar Panels (5)1光伏电力系统光伏电力系统利用太阳能电池吸收太阳光线，并将这种能量转化成电能。

这个系统让广大家庭通过一种清洁，可靠，平静的方式来产生电能，这样就可以补偿将来的部分电能支出，也减少了对输电网的依赖。

太阳能电池一般是由经改进的硅，或者其他能够吸收阳光并将之转化成电能的半导体材料制成。

太阳能电池是相当耐用的（1954年在美国安装的第一个光伏电力系统至今仍在运营）。

绝大多数的生厂商都担保自己的产品的电源输出至少维持20年。

但大多数的有关太阳能研究的专家认为一个光伏电力系统至少能维持25到30年。

1.1 太阳能电池的类型目前有单晶硅，多晶硅和薄膜三种基本形式的光伏组件。

这些类型的电池工作效率都很好但单晶硅电池效率最好。

薄膜技术的电池以成本低为特色，而且伴随着太阳能电池板的发展它的效率也在不断地提高。

越来越多的生厂商以及各种各样的电池型号在当今市场上出现。

一个太阳能技术的支持者可以帮你分析各个系统的利弊，如此你就可以得到为你所用数十年的最佳的系统设计方案。

1.2光伏电力系统如何运作光电板通常安装在建筑物顶部，通过逆变器来引到建筑物中。

逆变器将通过太阳能板产生的直流电转化成交流电，而在当今美国交流电是向建筑提供电动力的主要形式。

朝南方向的太阳能板能使能量的收集效果最大化，大部分都是与建筑物顶部成60度的位置安放太阳能电池。

有关太阳能电池发电的更多的信息，可以查询Cooler Planet’s的《太阳能电池如何工作》。

朝南方向的太阳能板能使能量的收集效果最大化，大部分都是与建筑物顶部成60度的位置安放太阳能电池。

1.3 太阳能电池板与光伏建筑一体化太阳能电池板是用于捕获太阳光的平面板，他们以阵列的形式安装在建筑物顶部或者柱子上。

他们是传统的用于获得太阳能的阵列形式。

文献翻译英文原文：Solar electrical energy generationAlong with economical development, society's progress, the people to the energy proposed that more and more high request, seeks for the new energy to become the urgent topic which the current humanity faces. The existing energy mainly has 3 kinds, namely thermal power, water and electricity and nuclear power.The thermal power needs to burn fossil fuels and so on bunker coal, petroleum. On the one hand the fossil fuel reserves limited, the fever are less, is facing the danger which dries up. It is estimated that the world oil resource will have 30 years then to dry up again. On the other hand the combustion fuel will discharge CO2 and the sulfur oxide compound, will therefore cause the greenhouse effect and the acid rain, will worsen the terrestrial environment.The water and electricity must submerge the massive lands, has the possibility to cause the ecological environment to destroy, moreover large reservoir, once collapses, the consequence will be inconceivable. Moreover, country's hydro-electric resources are also limited, moreover must receive the season influence.The nuclear power in the normal condition no doubt is clean, but has the nuclear leakage accidentally, the consequence is similarly fearful. The former Soviet Union Chernobyl Nuclear Power Station accident, has caused 9,000,000 people to receive the varying degree harm, moreover this influence has not terminated.These force the people to seek for the new energy. The new energy must simultaneously meet two conditions: First, the implication rich will not dry up; Second, is safe, is clean, will not threaten the humanity and the destruction environment. At present found the new energy mainly had two kinds：first, solar energy; second, fuel cell. Moreover, the wind power generation may also be the auxiliary new energy. And, the most ideal new energy is greatly positive energy.1. The solar electrical energy generation is the most ideal new energyShines is huge on Earth's solar energy, about 40 minutes shine on Earth's solar energy, then sufficiently supplies global humanity one year energy the expense. It can be said that the solar energy is true inexhaustible, the inexhaustible energy. Moreover the solar electrical energy generation is absolutely clean, does not have the environmental damage. Therefore the solar electrical energy generation is honored asis the ideal energy.Obtains the electric power from the solar energy, must carry on the electro-optical transformation through the greatly positive battery to realize. It completely was formerly different with other power source electricity generation principle, has the following characteristic: ①Non-depletion danger; ②Clean (does not have environmental damage) absolutely; ③It is not distributed the resources the region the limit; ④But is using electricity place nearby generates electricity; ⑤The energy quality is high; ⑥The user easy to accept from the sentiment; ⑦The gain energy expenditure's time is short. The deficiency is:①The illumination energy distribution density is small, namely must take the huge area; ②Obtains the energy with four seasons, the day and nights and cloudy clear and so on meteorological conditions concerns. But generally speaking, the flaw does not cover the fine jade, takes the new energy, the solar energy has the enormous merit, therefore receives various countries the value.Must enable the solar electrical energy generation to achieve the practical level truly; first, must raise the solar energy electro-optic conversion efficiency and reduce its cost; second, must realize the solar electrical energy generation with present's electrical network networking.At present, solar panels mainly has the mono-crystalline silicon, the polycrystalline silicon, the amorphous state silicon three kinds. The mono-crystalline silicon solar cell conversion efficiency is highest, has reached above 20%, but the price is also the most expensive. The amorphous state silicon solar cell conversion efficiency is lowest, but the price is the cheapest, from now on most will be hopeful uses in generally generating electricity will be this kind of battery. Once its big area module electro-optic conversion efficiency achieves 10%, each watt generating set price falls to 1-2 US dollars, then sufficiently compete with present's electricity generation way. It is estimated that at the end of this century it may achieve this level.Certainly, in the special use and the laboratory uses the solar cell efficiency must be much higher, if the US Boeing develops by the gallium arsenic semiconductor with the positive electricity place which too the stibium gallium semiconductor overlaps becomes, the electro-optic conversion efficiency may reach 36%, has caught up with the coal-burning electricity generation efficiency quickly. But because it is too expensive, at present can only be restricted on the satellite uses.2. Solar electrical energy generation applicationAlthough solar electrical energy generation day and nights, clear and rain, season influence, but may carry on scattered, therefore it is suitable for various each household minute to carry on the electricity generation severally, moreover must join in the power supply network, causes each family when the electric power is wealthy may sold it to the Electricity company, when the insufficiency be possible from the Electricity company to buy up. Realizes this point’s technology not to be difficult to solve, the key lies in must have the corresponding legal safeguard. Now the US, Japan and so on developed country has made the corresponding law, guaranteed that carries on the solar electrical energy generation the family benefit, encourages the family to carry on the solar electrical energy generation.Japan has realized the solar electrical energy generation system the same electricity company electrical network's networking in April, 1992, had some families to start to install the solar electrical energy generation equipment. The Japanese Ministry of International Trade and Industry started from 1994 take individual housing as an object, implemented to purchases the solar electrical energy generation equipment's expense to subsidize 2/3 systems. Requests the first year had 1000 households families, when 2000 to have 70,000 households families to install the solar electrical energy generation equipment.According to the Japanese Department concerned estimates in the Japanese 21,000,000 households individual housing, if has 80% to install the solar electrical energy generation equipment, then may satisfy 14% which the national total power needs, if units and so on factory and office building also carry on the solar electrical energy generation with the room, then the solar electrical energy generation will occupy the national electric power 30%-40%. The current hindrance solar electrical energy generation popular most primary factor is the expense is expensive In order to satisfy the general family power requirement 3 kilowatt generating system, needs 6,000,000 to 7,000,000 Japanese Yen, has not included the installment wages. The concerned expert believed that when must fall at least to 1,000,000 to 2,000,000 Japanese Yen, the solar electrical energy generation only then can popularize truly. The key to reduce the expense lie in the solar cell to raise the conversion efficiency and to reduce the cost.Some time ago, the US Texas Instruments Company and SCE Corporation announced that they develop one kind of new solar cell, each unit is the diameter less than 1 millimeter bead, they distribute regularly densely and numerously on the softaluminum foil, looks like many silkworm eggs to cling on the paper is the same. Then distributes in about 50 square centimeters area has 1,700 such units. This kind of new battery's characteristic is, although the conversion efficiency has 8%-10%, but the price is cheap. Moreover aluminum foil bottom bush soft solid, may look like the cloth to fold equally at will, and durable, hangs in toward the sun place then may generate electricity, is convenient. It is said that uses this kind of new solar cell, so long as each watt power capacity equipment 1.5 to 2 US dollars, moreover each round of once electricity's expense might also fall to 14 cents about, definitely may compete with the ordinary power plant. Each family hangs this kind of battery on the roof, the wall toward the sun, every year may obtain 1,000-2,000 degrees electric powers.3. Solar electrical energy generation prospectThe solar electrical energy generation has a more exciting plan. First, Japan proposes creates the century plan. Prepares the desert and the sea area carries on the electricity generation using the ground, and through superconducting cable whole world solar power station connection unification electrical network in order to global. According to reckoning, to 2000, in 2050, in 2100, even if all uses the solar electrical energy generation supplies the whole world energy, the occupying land area is also 651,100 square kilometer, 1,867,900 square kilometer, 8,291,900 square kilometers. 8,291,900 square kilometers only occupy the complete sea area 2.3% or the complete desert area 51.4%, even is the Sahara area 91.5%. Therefore this plan has the possibility to realize.Another one is the space electricity generation plan. As early as in 1980 the NASA and Department of Energy proposed that in the spatial construction solar power station tentative plan, prepares on the synchronous orbit to put one long 10 kilometers, to extend 5 kilometer big plates, above covers entirely the solar cell, like this then may provide 5,000,000 kilowatts electric powers. But this needs to solve to the ground wireless electric transmission question. Already proposed with the micro wave beam, the laser beam and so on each kind of plan. At present although has realized the short distance, the short time, the low power microwave wireless electric transmission with the mockup, but to true practical also has the long distance.Along with our country technology's development, in 2006, China had three enterprises to enter global first ten, symbolizes that China will become one of global new energy science and technology central, in the world the solar energy light bends down widespread application, what caused present to be deficient was raw materialsupply and the price rise, we needed dissemination of technology at the same time, to use the new technology, with the aim of reducing the cost large scale, was this new energy long-term development provides the driving force!The solar energy use mainly divides into several aspects: The family with the small solar energy power plant, the large-scale incorporation power plant, the building integration light bends down the glass curtain wall, the solar energy street light, the scenery supplementary street light, the scenery supplementary power supply system and so on, now main application way for construction integration and scenery supplementary system.The world present had the nearly 200 companies to produce the solar cell, but produces the plants mainly hand in the Japanese business.Recent years the South Korean Tri-star, LG expressed the positive participation's desire, China two sides across the Taiwan Strait are similarly very warm-hearted. It is reported that our country Taiwan in 2008 crystallizes the silicon solar cell productivity to reach 2.2GW, later will expand by every year 1GW productivity in the past and started to produce the thin film solar cell, this year will strengthen vigorously, Taiwan anticipated that “the solar cell great nation” emulated to Europe. in 2010 various countries and the area have above 1GW the productive plan solar cell manufacturer to have Japanese Sharp, German Q-Cells, Scho~Solar, turns 5 prestige RWE Solar, Chinese Suntech Power and so on 5 companies, above other 7 500MW productivity company.Recent years the world solar cell market advanced triumphantly, an excellence, but the rare financial storm brought the economic crisis, was similarly presses in solar cell market on dark clouds, the Major enterprise like Germany Q-Cells achievement declined accordingly, because pre-year the world too positive electricity market also the demand will be this year worn out, the petroleum price dropped, but the competitive power counter-promotion and so on disadvantage factor lowered But at the same time, the people also see the US. After the Obama comes on stage, soon applies the Green New Deal policy, may have 150,000,000,000 US dollar subsidy funds including the among them green energy program, Japan will also carry out the subsidy system to continue to popularize solar cell's application4. Solar cell electricity generation principle:The solar cell is pair of light has the response and can transform the energy of light the electric power the component. Many kinds of materials can produce the lightto bend down the effect, for example: Mono-crystalline silicon, polycrystalline silicon, amorphous silicon, gallium arsenic, selenium indium copper and so on. Their electricity generation principle basic same, presently take crystal as example description light electricity generation process. The P crystalline silicon may result in the N silicon after the doping phosphorus, forms the P-N knot.When light illumination solar cell surface, part of photons by silicon material absorption; The photon energy transfer has given the silicon atom, caused the electron to occur more moved, becomes the free electron to tie the both sides in P-N to gather has formed the potential difference, when exterior key-on, under this voltage's function, will have the electric current to wind through the exterior electric circuit to have certain output. This process's essence is: The photon energy transforms the electrical energy the process.5. Crystalline silicon solar cell's manufacture process:The silicon is on our star preserves one of most abundant quantity materials. Had discovered after the 19th century scientists crystalline silicon semiconductor characteristic, it changed all nearly, even humanity's thought. 20 century's ends, in our life everywhere obviously “silicon” the f orm and the function, the crystalline silicon solar cell is in the recent 15 years forms the industrial production to be quickest. The production process may divide into five steps approximately: a、depuration process.b、pulls good process.c、slice process.d、system battery process.e、and the seal process.6. Solar cell's application:In the 1960s, the scientists already applied the solar cells in the spatial technology-communication satellite power supply, on the century's end, in the human self-introspection's process, bends down unceasingly regarding the light generates electricity this kind so clean and the direct energy form already even more kind, not only in the spatial application, but also gives full play in the numerous domains.For example: The solar energy garden lamp, the solar electrical energy generation household with the system, the stockaded village power supply's independent system, the light bends down the water pump (potable water or irrigation), the correspondence power source, the petroleum oil pipeline cathodic protection, the fiber optic cable communications pumping station power source, in the seawater desalination system, the cities the guidepost, the highway guidepost and so on. Europe and America and so on advanced countries bend down the electricitygeneration the light to merge the city to use electricity the system and the remote border district nature village power supply system integrate the development direction. The solar cell and the building system's union already formed the industrial production tendency.参考译文：太阳能发电随着经济的发展、社会的进步，人们对能源提出越来越高的要求，寻找新能源成为当前人类面临的迫切课题。

Solar Tracker for Solar Water HeaterAbstractThe Solar Tracker team was formed in the fall of 2005 from five students in an ME design team, and a Smart House liaison. We continued the work of a previous solar tracker group. The task was to design a prototype tracking device to align solar panels optimally to the sun as it moves over the course of the day. The implementation of such a system dramatically increases the efficiency of solar panels used to power the Smart House. This report examines the process of designing and constructing the prototype, the experiences and problems encountered, and suggestions for continuing the project.1.IntroductionSolar tracking is the process of varying the angle of solar panels and collectors to take advantage o f the full amount of the sun’s energy. This is done by rotating panels to be perpendicular to the sun’s angle of incidence. Initial tests in industry suggest that this process can increase the efficiency of a solar power system by up to 50%. Given those gains, it is an attractive way to enhance an existing solar power system. The goal is to build a rig that will accomplish the solar tracking and realize the maximum increase in efficiency. The ultimate goal is that the project will be cost effective – that is, the gains received by increased efficiency will more than offset the one time cost of developing the rig over time. In addition to the functional goals, the Smart House set forth the other following goals for our project: it must not draw external power (self-sustaining), it must be aesthetically pleasing, and it must be weatherproof.The design of our solar tracker consists of three components: the frame, the sensor, and the drive system. Each was carefully reviewed and tested, instituting changes and improvements along the design process. The frame for the tracker is an aluminum prismatic frame supplied by the previous solar tracking group. It utilizes an ‘A-frame’ design with the rotating axle in the middle. Attached to the bottom of this square channel axle is the platform which will house the main solarcollecting panels. The frame itself is at an angle to direct the panels toward the sun (along with the inclination of the roof). Its rotation tracks the sun from east to west during the day.The sensor design for the system uses two small solar panels that lie on the same plane as the collecting panels. These sensor panels have mirrors vertically attached between them so that, unless the mirror faces do not receive any sun, they are shading one of the panels, while the other is receiving full sunlight. Our sensor relies on this difference in light, which results in a large impedance difference across the panels, to drive the motor in the proper direction until again, the mirrors are not seeing any sunlight, at which point both solar panels on the sensor receive equal sunlight and no power difference is seen.After evaluation of the previous direct drive system for the tracker, we designed a belt system that would be easier to maintain in the case of a failure. On one end of the frame is a motor that has the drive pulley attached to its output shaft. The motor rotates the drive belt which then rotates the pulley on the axle. This system is simple and easily disassembled. It is easy to interchange motors as needed for further testing and also allows for optimization of the final gear ratio for response of the tracker.As with any design process there were several setbacks to our progress. The first and foremost was inclement weather which denied us of valuable testing time. Despite the setbacks, we believe this design and prototype to be a very valuable proof-of-principle. During our testing we have eliminated many of the repetitive problems with the motor and wiring so that future work on the project will go more smoothly. We also have achieved our goal of tracking the sun in a ‘hands-off’ demo. We were able to have the tracker rotate under its own power to the angle of the sun and stop without any assistance. This was the main goal set forth to us by the Smart House so we believe our sensed motion prototype for solar tracking will be the foundation as they move forward in the future development and implementation of this technology to the house.2. Defining the ProblemThe project was to complete the “REV 2” design phase of the solar tracker to be used on the Smart House. While the team was comprised of members from the ME160 senior design course, the customer for this project was to be the Smart House organization. Jeff Schwane, a representative from the Smart House, was our liaison and communicated to our group the direction Smart House leadership wished us to proceed.At our first meeting with Jeff and Tom Rose, the following needs were identified:1.Track the sun during the daye no external power source3.Weather proof4.Cost effective power gain5.Must look good6.Solar panel versatile i.e. can fit different types of panelsWith these needs in hand, we constructed a Quality Function Deployment chart. This chart can be found in Appendix A. The QFD showed the major areas of concern might have been: number of panels/size of panels, internal power requirements, motor torque required.At our first meeting we were also able to set up our goals for the semester. Having a working prototype capable of tracking the sun was to be the main goal for the end of the semester, but we soon found that in order to accomplish this, we would be forced to omit portions of the design criteria in hopes they would be worked out later. This would result in the optimization of platform space on the roof to be irrelevant, with our goal being to have one platform track. It also led to the assumption that our base would not need to be tested for stability or required to be fastened to the roof. With an idea of where we were to begin, from scratch with the possibility of using the frame from the “REV 1” design, and an idea of where we were to finish, with a moving prototype, we constructed the Gantt chart that can be found in Appendix B. Our group planned to meet with Jeff once a week to make sure we were on track with the needs of the Smart House. Jeff would also meet with Tom Rose, the director of Smart House, at least once a week in order to keep everyone on the same page. With our goals in mind weembarked on the process of idea generation.3. Concepts and Research3.1 Tracking TypeOur group used a brainstorming approach to concept generation. We thought of ideas for different solar tracking devices, which proved difficult at times due to the existing frame and concept presented to us by Smart House. Other concepts were generated through research of pre-existing solar tracking devices. Originally our concept generation was geared towards creating a completely new solar tracker outside of the constraints of the previous structure given to us by Smart House. This initial brainstorming generated many concepts. The first one was a uni-axial tracking system that would track the sun east to west across the sky during the course of a day and return at the end of the day. This concept presented the advantage of simplicity and presented us with the option to use materials from the previous structure (which was also intended to be a uni-axial tracker) in construction. Another more complex concept was to track the sun bi-axially which would involve tracking the sun both east to west and throughout the seasons. The advantage of this concept was a more efficient harvesting of solar energy. The third concept was to only track throughout the seasons. This would provide small efficiency gains but nowhere near the gain provided by tracking east to west.The different structures we came up with to accomplish tracking motion included a rotating center axle with attached panels, hydraulic or motorized lifts which would move the main panel in the direction of the sun, and a robotic arm which would turn to face the sun. The clear efficiency gains coupled with the simplicity of design of the uni-axial tracking system and the existence of usable parts (i.e. motor and axle) for the rotating center axle structure, led us to the choice of the East to West tracking, rotating center axle concept.3.2 StructureOnce the method of motion was chosen, it was necessary to generate concepts for the structural support of the axle. Support could be provided by the triangular prismatic structure which was attempted by the previousSmart House solar tracker group or through the use of columns which would support the axis on either side. While the prismatic structure presented the advantage of mobility and an existing frame, the columns would have provided us with ease of construction, simple geometric considerations, and ease of prospective mounting on the roof. Due to the heightened intensity of time considerations, the previous financial commitment to the prismatic structure by Smart House, and our limited budget, the presence of the pre-existing frame proved to be the most important factor in deciding on a structure. Due to these factors we decided to work within the frame which was provided to us from the previous Solar Tracker group.3.2 Tracking MotionOnce the structural support was finalized we needed to decide on a means to actualize this motion. We decided between sensed motion, which would sense the sun’s position and move to follow it, and continuous clock type motion, which would track the sun based on its pre-determined position in the sky. We chose the concept of continuous motion based on its perceived accuracy and the existence of known timing technology. During the evaluation stage, however, we realized that continuous motion would prove difficult. One reason was the inability to draw constant voltage and current from the solar panels necessary to sustain consistent motion, resulting in the necessity for sensing the rotation position to compensate. Continuous motion also required nearly constant power throughout the day, which would require a mechanism to store power. Aside from these considerations, the implementation of a timing circuit and location sensing device seemed daunting. After consulting Dr. Rhett George, we decided on a device using two panels and shading for sensed motion.4. Analysis and Embodiment4.1 Structure GeometryThe geometry of the frame was created in order to allow the solar panels to absorb light efficiently. This was done by allowing rotation in the east-west direction for tracking the sun daily and a 36°inclination (Durham’s latitude) towards the south. Because this frame was designedto be placed on a roof with a slope of 25°, the actual incline of the frame was made to be 11°.The geometry of the existing platform structure was modified. This was done in order to incorporate the results from the Clear Day Model supplied to us by Dr. Knight. This model led to the conclusion that the platform should track to up to 60° in both directions of horizontal. Thus, the angle range of the frame had to be increased. The sides of the frame were brought in to increase the allowable angle of rotation, and they were brought in proportionally to maintain the inclination angle of 11°. Also, crosspieces were moved to the inside of the frame to allow greater rotation of the platform before it came into contact with the support structure.The panels used for sensing and powering rotation were placed on the plane of the platform. Mirrors were placed perpendicular to and in between the panels to shade one and amplify the other in order to produce a difference to power the motor. The sensing panels were placed outside the platform area to maintain the largest area possible for collecting panels. A third sensing panel was mounted nearly vertical and facing east to aid rotation back towards the sun in the morning. This panel was attached to the frame under the platform, so that during most of the day, it’s shaded with minimal effec ts on sensed rotation.Minimizing the torques on the motor was a main concern in order to minimize the motor power needed. The platform designed for the placement of the collecting solar panels was placed under the rotational shaft so that the panels would be aligned with it the rotational axis. Since the main panels comprise the majority of the weight putting these in the plane of the rotational axis reduces torque on the shaft. The sensing panels were placed symmetrically about the axis of rotation in order to prevent additional torque on the motor. The third panel was attached to the frame instead of the platform or rotational shaft so as to also avoid any torque.4.2 MaterialsMaterials selection for most of the frame was simple because it had already been constructed. The mirrors used for the amplification andshading of the sensing panels were also already purchased and available for use. Additional parts for attachment of the panels and mirrors to the frame were taken from the scrap pieces available in the machine shop. In our selection of sensing panels, size and power needed to be balanced effectively. The panels were to be as small as possible in order to add minimal stress and weight to the frame but also needed to be powerful enough to power the rotation of the platform. Therefore, the most powerful of the intermediate sized panels available were selected. The panels purchased also appeared to be the most reliable of our options. 4.3 Drive MechanismAfter designing a prototype and testing it, the motor purchased and used by the previous solar tracker group was slipping. It was removed, and the installation of a gear system with another simple motor was suggested and attempted. Professor Knight supplied some gears as well as some belts and pulleys. One end of the shaft was lathed so that one of the pulleys could be set on it, and spacers were bought so that a 6V motor we had available could power another pulley. These pulleys were to be connected by a belt. This motor demonstrated insufficient strength to turn the rotational shaft. The original motor, once detached, was taken apart and examined. Itappeared to be working again so a new pulley was purchased to fit it and was attached in the place of the 6V motor.5. Detailed Design5.1 FrameThe frame was designed from one inch square aluminum tubing, and a five foot long, two inch square tube for the axle. It is constructed with a rigid base and triangular prismatic frame with side supporting bars that provide stability. The end of the axle is attached to a system of pulleys which are driven by the motor. It is easily transported by removing the sides of the base and folding the structure.5.2 SensorOur sensing panels are bolted to the bottom of the main solar panel frame and braced underneath with half inch L-brackets. The mirrors are attached to the inside of the sensing panels and braced by L-brackets as well. The whole structure attaches easily to the main panel frame which isattached to the main axle using four 2-inch U-bolts. A third panel is bolted to the structure to return the main panels direction towards the horizon of sunrise.5.3 How the Sensor WorksOur sensor creates movement of the motor by shading one of the panels and amplifying the other when the system is not directly facing the sun. The two sensing panels are mounted parallel to the main panels symmetrically about the center axle with two mirrors in between them. The shading on one of the panels creates high impedance, while the amplified panel powers the motor. This happens until the panels receive the same amount of sunlight and balance each other out (i.e. when the sensing panels and main panels are facing the sun.). We initially attempted using a series configuration to take advantage of the voltage difference when one of the panels was shaded (Appendix C). This difference, however, was not large enough to drive the motor. We subsequently attempted a parallel configuration which would take advantage of the impedance of the shaded panel (Appendix C) and provide the current needed to drive the motor. Once the sensing mechanism has rotated from sunrise to sunset, the third panel, which is usually shaded, uses sunlight from the sunrise of the next day to power the motor to return the panels towards the direction of the sun.6. Prototype TestingInitial testing was done using just the sensing component and a 6V motor. The panels were tilted by hand to create shading and amplification.A series configuration of the sensing panels was initially tested and proved ineffective. Data acquisition showed a maximum of a 2V difference across the motor, which was insufficient to power it. Upon testing the panels individually, it was discovered that the open voltage across each individual panel would only vary between 21.5V and 19.5V when fully amplified and fully shaded, respectively. The current running through each panel, however, was seen to fluctuate between nearly 0 amps when shaded, up to 0.65 amps when fully amplified. Therefore, in order to take advantage of the increase in impedance of the solar panels due to shading, we chose to put our sensing panels in parallel with eachother and the motor. Tests with this configuration turned the motor in one direction, stopped when the sensing panels were nearly perpendicular to the sun, and reversed direction as the panels rotated past perpendicular. We found the angle range necessary to stop the motor to be very small. It was also observed that the panels rotated to slightly past perpendicular when they ceased motion. This error may be due to a difference in the innate resistance in each individual sensing panel. When tested it was found that one panel had a resistance of 52 kΩ, and the other panel resistance was 53 kΩ. Other testing found the voltage and current provided by the sensing solar panels to the motor to be consistent at all points, excluding when the solar panels are directly facing the sun. Through testing it was concluded that resistance may need to be added to one of the panels to compensate for the differences in the internal resistances of the individual panels, and a voltage regulator needs to be added to decrease the voltage seen across the motor. The original motor was prone to failure as its slippage caused the breakdown of our initial prototype after testing. This led to the institution of the pulley and belt driven system which would allow for easier maintenance given motor failure or slippage. The success of our initial testing and prototype proved to us the efficacy of our solar tracker design.7. ConclusionThroughout this project we enlisted the support of multiple resources (i.e. ME and EE professors, previous Smart House teams). We learned early on that a clear problem definition was essential to efficient design and progress. We struggled initially as we tried to design a tracking device that was diffe rent from the previous solar tracker group’s attempt, without fully weighing the size of their investment and the advantages of using the existing frame for our purposes. As we worked with the fixed frame construction from the previous group we learned that variability of design is key, especially when in the initial phases of prototyping. After many setbacks in testing of the solar panels, we learned that when working with solar panels, much time needs to be set aside for testing due to the unpredictability of the weather.The actual implementation of using the prototype in its intendedlocation on the Smart House roof requires weather-proofing to protect the wiring and electrical connections from the elements, housing for the motor, a bracing system to attach the structure to the roof, and possible redesign to eliminate excess height and simplify overall geometry. The efficiency of the sensor system could be improved by widening the mirrors or by placing blinders along the sides of the panels to decrease the effects of reflected and refracted light incident on the shaded sensing panel.适用于太阳能热水器的太阳能跟踪器摘要太阳能跟踪器设计团队成立于2005年秋季，设计团队由五名队员组成，我们还负责与智能家居的联络工作。