哈尔滨工业大学工学硕士学位论文
Abstract
With the rapid development of consumer electronics, the demands of portable power conversion with high power density and high efficiency are ever increasing. In the field of low-power adaptor, the traditional quasi-resonant flyback converter cannot fully recover the energy stored in the leakage inductance of the transformer. Active clamp flyback converter can solve this problem and becomes a research hotspot. Therefore, this dissertation carries out the research on the application of active clamp flyback converter in the field of adaptor, and analyzes the operation of this topology under different resonant conditions.
In view of the complex working process of active clamp flyback converter and the large influence of parasitic components, this dissertation analyzes the working process of this circuit in different operating modes, and the circuit equivalent model is established to conduct mathematical demonstration. This dissertation also focuses on the achieving process of primary side soft-switching and gives the corresponding realizing conditions.
In order to solve the problem that the secondary side synchronous rectifier may malfunction with the traditional active clamp flyback converter, this dissertation studies the circuit working process under different resonant conditions and proposes a solution of primary-secondary side resonance. The causes of the malfunction of the synchronous rectifier under the traditional primary resonance conditions is analyzed, and the equivalent circuit model for the primary current drop phenomenon in this process is established. Under this premise, this dissertation studies the resonant characteristics of the circuit under the condition of the traditional primary resonance and the novel secondary resonance. Based on this, this dissertation proposes the working mode of the primary-secondary resonance. After theoretical analysis and experimental demonstration, it is proved that this method can effectively reduce the RMS of the secondary current and preserves the advantage of the secondary resonance in the same time.
According to the background of portable adaptor applications, this dissertation presents the design of an active clamp flyback power supply system, which is verified by the simulation in Simplis. At the same time, the primary-secondary side resonant working mode is implemented on the hardware platform which proves the consistency of theory and experiment.
Keywords: active clamp, soft-switching, flyback, primary-secondary side resonance
哈尔滨工业大学工学硕士学位论文
目录
摘要 .......................................................................................................................... I ABSTRACT................................................................................................................ II 第1章绪论 .. (1)
1.1课题背景及研究的目的和意义 (1)
1.2国内外研究现状分析 (2)
1.2.1 反激变换器在外置电源领域的发展 (2)
1.2.2 有源箝位反激变换器的研究现状分析 (4)
1.3本文的主要研究内容 (6)
第2章有源箝位反激电路箝位方式与工作模态分析 (8)
2.1引言 (8)
2.2有源箝位反激电路两种箝位方式分析 (8)
2.2.1 高边箝位方式 (8)
2.2.2 低边箝位方式 (9)
2.3有源箝位反激电路不同工作模式下的模态分析 (10)
2.3.2 有源箝位反激电路在CCM模式下的工作模态分析 (10)
2.3.3 有源箝位反激电路在CrCM模式下的工作模态分析 (17)
2.4本章小结 (18)
第3章系统主电路参数计算与补偿网络设计 (19)
3.1引言 (19)
3.2主电路参数计算 (19)
3.2.1 变压器参数计算 (19)
3.2.2 输出电容计算 (21)
3.2.3 箝位电容计算 (21)
3.3小信号建模与补偿环路设计 (24)
3.3.1 考虑输出电容ESR的反激小信号建模 (24)
3.3.2 补偿环路的设计 (25)
3.4本章小结 (27)
第4章谐振方式对有源钳位反激电路的影响 (28)
4.1引言 (28)
4.2采用原边谐振的有源箝位反激电路分析 (28)
4.2.1 电流跌落过程分析 (28)
哈尔滨工业大学工学硕士学位论文
4.3副边参与谐振的有源箝位反激电路分析 (36)
4.3.1 副边单独参与谐振的电路工作过程分析 (36)
4.3.2 原副边同时参与谐振的电路特征分析 (37)
4.4本章小结 (38)
第5章仿真与实验结果分析 (40)
5.1引言 (40)
5.2SIMETRIX/SIMPLIS仿真实验分析 (40)
5.2.1 电容对谐振过程影响实验 (40)
5.2.2 软开关实验 (41)
5.2.3 系统暂态和稳态性能的实验 (46)
5.3硬件平台实验分析 (48)
5.4本章小结 (52)
结论 (53)
参考文献 (54)
哈尔滨工业大学学位论文原创性声明和使用权限 (58)
致谢 (59)