Study Of High-power IGBTs In Series Or Parallel

With the development and maturation, voltage and current capability of IGBTcontinues to strengthen. As the high-power full-controlled devices, IGBT showobvious advantages compared with GTO, BJT, IGCT etc in high power applications.But a single IGBT capacity still can not meet the voltage and current capabilityrequirements in IGBT applications. In order to increase the power level of the powerelectronic devices, require dozens of IGBTs in series and parallel to increase thecapacity.At first, this paper describes and analyzes the basic structure of the IGBT,working principle, static and dynamic characteristics and basic paramet ers. On thisbasis, summarizes the main IGBT series and parallel technology applications area,and summarizes the series and parallel IGBT technology domestic and abroad.Then analyzed the reason of causes of IGBT series voltage imbalance from itsown parameters and peripheral circuits, and Inductioned and summarized thesereasons. On this basis, discussed the feasibility and limitation of traditional RCDmethod. Similarly, analyzed and summarized the reasons of parallel IGBT currentimbalance, and introduced the feasibility and limitation of use transformers to achieveparallel current balance.And then for IGBT series voltage imbalance, proposed a series method which isbased on IGBT gate control, detailed described its structure and principle, andanalysised the selection and optimization the circuit structure parameters. Thendemonstrated the feasibility and advantages of this method by PSPICE, and comparedwith conventional RCD method.Next for the limitation of conventional RCD snubber circuit, propos ed an IGBTseries method which is based on the load side, and then detailed descri bed andanalysised of its structure and principles, then demonstrated this method can achieve agood series IGBT voltage balance by PSPICE, and compared its advantages with thetraditional RCD method.Finally discussed an IGBT module balanced current approach which by adjustinggate resistor. Based on the analysis of the main reasons of imbalance current betweeninternal cellular in the whole wafer IGBT, proposed achieve a balanced whole-waferIGBT internal cellular shunt current by changing the gate resistor. PSPICE simulation result indicates that this method can overcome the internal cellular current imbalancein the entire wafer of cellular IGBT.