Nｅw Generaｔiｏn of Hiｇh– Power Sｅｍiconductor ＣlｏsinｇSwiｔｃhes fｏr PｕlsｅｄPower Apｐliｃatioｎs
I.Iｎtｒｏduction
Soliｄstate semiconｄuｃtor switches are verｙinviting tｏuse aｔｐulｓed poweｒｓystems beｃause ｔｈese ｓwitches hａｖe hｉgh reｌiａbiliｔy, lonｇlif ｅtime, lｏw coｓｔs duｒinｇusiｎg, aｎd ｅnvironmenｔaｌsafetｙduｅtｏｍｅｒｃury aｎd lead ａｒe ａｂsent. Semｉconductoｒsｗiｔches arｅaｂle to wor ｋin any positioｎ,ｓo, it is ｐosｓiｂｌｅto design ｓysteｍs as foｒsｔａｔiｏnary ｌaboratｏｒy usｉｎg, aｎd ｆor mobiｌｅuｓｉnｇ．Therefｏre theseｓwiｔc ｈes aｒe freｑuentlyｒeｇardｅd ａsｒｅｐlacｅment oｆgaｓ-dｉschａrgｅd ｅvicｅs–ｉｇｎitrons,thyratrｏns,sparｋgaｐｓａnd vaｃuum switcｈes ｔhatｇenｅrally uｓe ｎow iｎhigh-powerｅleｃtｒophｙsｉcal systems inｃlｕding powｅｒlａsｅrs．
Trａｄiｔional tｈyｒisｔorｓ(SCR) aｒｅｓｅmiconduｃｔｏr sｗitches mostly usiｎｇfｏr ｐulseｄevicｅs．ＳＣR hａｓｓmaｌl vａlue of ｆorｗａｒd vol ｔaｇe drop at switｃh-ｏn sｔatｅ,iｔhaｓhiｇｈoverloadｃapａciｔy for curr ｅｎｔ, and aｔlasｔｉｔhas reｌａｔiｖely low coｓtｖalｕe ｄuｅtｏｔhe siｍpｌｅbipolaｒtｅcｈnoloｇy. Diｓａdvanｔａge of SCR ｉs oｂseｒｖeｄat switc ｈinｇof currenｔｐuｌsesｗiｔｈverｙhｉghｐeａk vａlue aｎd shｏrt du ｒatｉoｎ. Reａsoｎof thiｓdisadvanｔagｅiｓsufficｉently ｓｌoｗproｃｅｓs oｆswiｔｃh-ｏn ｓｔatｅｅxpａnsｉon frｏm trigｇering elｅctrｏde ｔo extｅrnal bｏrdｅr of p-n junｃtion after ｔrｉｇgerｉnｇpｕlｓe ａpplyinｇ. This SＣR ｆeature is defined SCR ｕsinｇｉnto mｉllｉsｅcond rangｅof curreｎt sｗitchiｎｇ. Ｉｍpｒovemeｎt of SCR pｕlｓｅcｈａractｅｒistics can bｅreacheｄby ｕsinｇof the ｄistribｕｔｅd gatｅdesign. Thiｓis alloｗed to ｄｅcrｅａse ｔｈｅtiｍe of totａl swｉｔｃｈ-on and ｇreａtｌｙimprove SＣＲswitching cａpacitｙ. Ｔhus, ＡBB ｃｏmpａｎｙis expanded the semｉcｏnｄuctor swiｔch usiｎg up to mｉｃｒoseｃoｎd raｎgｅby desｉｇn oｆｓpｅcial pulseａsymmetｒic tｈｙrｉsｔorｓ
(ASCR ）. Thes ｅ d ｅvi ｃes have ｄistr ｉｂuti ｎg gate stru ｃtur ｅ ｌｉke a GTO. T ｈis th ｙrist ｏr des ｉgn ａn ｄ force ｄ tri ｇｇeri ｎg m ｏde ar ｅ obta ｉne ｄ the ｈig ｈ s ｗｉｔchin ｇ ｃａpaci ｔy o ｆ ｔh ｙｒis ｔor (p I =1５0kA, p T =５0μs, di/dt = 1８kA/μs, singl ｅ pul ｓe). However ， ｉn this ｄe ｓig ｎ ga ｔe s ｔructure ｉs c ｏver ｅｄ l ａrge a ｃｔive ａｒea of thyristor (ｍｏｒe ｔhan 50％) ｔh ａｔ de ｃre ａｓe ｔhe ｅffi ｃien ｃy ｏf S ｉ ｕsing ａnd ｉn ｃｒease cos ｔ of de ｖｉce.
Si-ｔｈyri ｓｔors a ｎd IG ＢT have ｄｅm ｏｎｓｔrated hi ｇh s ｗitchi ｎg charac ｔｅrist ｉcs at ｒｅpetit ｉv ｅ mode. Ｈowe ｖｅr, su ｃh devic ｅs ｄo not int ｅnd f ｏr s ｗｉt ｃhi ｎg ｏf hi ｇh ｐulse cu ｒr ｅnts (ｔens of kiloampere ｓ ａｎd more) bec ａuse of ｗｅll-kno ｗn phy ｓical ｌim ｉt ｓ a ｒe e ｘi ｓt ｅd s ｕｃh a ｓ lo ｗ d ｏpi ｎg ｏf ｅmi ｔter ｓ, shor ｔ li ｆｅtime o ｆ ｍi ｎｏrit ｙ c ａrrier ｓ, s ｍａｌl si ｚes of chips et ｃ．
O ｕｒ i ｎｖｅstigati ｏｎ ha ｖｅ obtai ｎe ｄ th ａt swi ｔches ｂa ｓｅd on re ｖe ｒse – ｓwitc ｈed din ｉsto ｒs are more p ｅrs ｐe ｃtive soli ｄ-ｓta ｔe s ｗi ｔches to ｓｗitch ｓup ｅr high p ｏwers a ｔ ｍicro ｓｅc ｏnd and s ｕｂm ｉllis ｅｃo ｎd rang ｅs ． R ｅv ｅr ｓe – sw ｉｔｃｈｅｄ dinis ｔｏrs (RSD) i ｓ ｔwo-electr ｏｄｅ analogue o ｆ ｒｅｖerse con ｄuct ｉng thyr ｉs ｔor ｗith mo ｎｏlit ｈica ｌ ｉn ｔe ｇｒate ｄ free ｗheeli ｎg d ｉod ｅ i ｎ S ｉ. Thi ｓ di ｏde is con ｎect ｅd in ｐarallel ａnd in t ｈe ｂa ｃｋ ｄire ｃti ｏn t ｏ th ｅ thyr ｉs ｔo ｒ part of ＲS Ｄ. Trig ｇｅr ｉng ｏf R ＳD ｉs prov ｉd ｅd by ｓho ｒt ｐuls ｅ of t ｒig ｇer curre ｎｔ a ｔ b ｒief app ｌy ｉng of r ｅv ｅrsal volt ａge t ｏ RSD. Des ｉgn of ＲＳD is made thus that triggerin ｇ current pas ｓes ｔhroug ｈ ｄio ｄe ar ｅas o ｆ RSD qu ａｓiaxially and ｕnif ｏrmly along ｔhe Si s ｔructu ｒe ａrea ． Ｔｈi ｓ curr ｅｎt p ｒod ｕc ｅｓ the onc ｏming inje ｃtion of char ｇe ca ｒｒi ｅｒｓ f ｒom both e ｍitter juncti ｏns to base r ｅgion ｓ ａｎd ｉn ｉｔia ｔes the regenera ｔive pro ｃe ｓs of ｓwitch-on for R ＳD thyris ｔｏｒ areas ． Suc ｈ ｍｅt ｈod ｏf t ｒｉg ｇeri ｎg f ｏｒ this spe ｃial des ｉｇn of Ｓi ｐlate is p ｒovided tot ａl ａnd uni ｆorm sw ｉtching of RSD ａlong ａll activ ｅ a ｒea in th ｅ ｖe ｒｙ sho ｒt ｔime lik ｅ as ｄiod ｅ s ｗitch-o ｎ. Ｔh ｅ ｆre ｅwh ｅｅling di ｏde i ｎtegr ａte ｄ int ｏ th ｅ ＲSD st ｒucture ｃould ｂe ｕsed ａs
