直流微网混合式断路器IGBT串联均压特性  

IGBT Series Voltage-sharing Characteristics of Hybrid Circuit Breaker in DC Micro-grid

作　　者：冷彤 王德全 廖敏夫[1] 邱军 王汝凡 邹积岩[1] LENG Tong;WANG Dequan;LIAO Minfu;QIU Jun;WANG Rufan;ZOU Jiyan(School of Electrical Engineering,Dalian University of Technology,Dalian 116024,China)

机构地区：[1]大连理工大学电气工程学院,大连116024

出　　处：《高电压技术》2020年第11期3879-3886,共8页High Voltage Engineering

基　　金：国家自然科学基金(51777025);中央高校基本科研业务费基金(DUT19ZD219)。

摘　　要：混合式断路器在直流微网应用中将多个绝缘栅双极晶体管(insulated gatebipolar transistor,IGBT)串联以承受关断过电压,为此对IGBT串联动态均压特性展开探讨。首先,分析了IGBT串联动态不均压原因及电阻、电容、二极管(RCD)无源缓冲均压电路工作原理;其次,通过仿真分析不同RCD电路参数对均压特性、IGBT关断损耗及过电压、二极管反向电压的影响;最后,搭建容量为1.2 kA/2.4 kV的IGBT串联开断单元,以500 ns关断时间差、600 A短路电流为实验条件,进行开断验证。研究结果表明:缓冲电容在一定范围内越大,IGBT的过电压、关断损耗、不均压程度越小,但过大的电容值对3者减小的作用有限;缓冲电阻在一定范围内越大,避雷器关断后,电路阻尼振荡的抑制效果越好,但二极管承受的反向电压会增大;结合仿真和实验,提出缓冲电容2~3μF,缓冲电阻2Ω的最佳电路参数,并在此基础上给出二极管选型原则。该文通过研究获得的RCD无源缓冲电路均压特性,可为工程应用提供一定技术参考。Series-connected insulation gate bipolar transistors(IGBTs) are applied to withstand the turnoff overvoltage in DC micro-grid hybrid circuit breaker. Thus, we investigated the series dynamic voltage-sharing of IGBTs. Firstly, we analyzed the causes of uneven dynamic voltage-sharing of IGBTs and the principle of RCD(resistor, capacitor, diode) snubber circuit. Then, we analyzed the voltage-sharing characteristic, overvoltage and turnoff loss of IGBTs, reverse voltage of diodes under different RCD circuit parameters by simulation. Finally, the 1.2 kV/2.4 kV power electronics interrupting unit with IGBTs in series was set up for verification. The short circuit current was 600 A, and the time difference between turn-off signals was 500 ns. The research indicates that, the larger the buffer capacitance in a certain range is, the smaller the overvoltage and turn-off loss of IGBTs will be, and the better the voltage-sharing will be;however, the excessive capacitance has a limited effect on the reduction of them. The larger the buffer resistance in a certain range is, the better the suppression of damped oscillation after turnoff of arrester will be;however, the reverse voltage of diodes will increase. The combined results of simulation and experiments show that the optimal circuit parameters of 2~3 μF buffer capacitance and 2 Ω buffer resistance are proposed, by which the principle of diode selection is given. The voltage-sharing characteristics of RCD snubber circuit are verified by investigation, which provides the technical reference for application in DC breaking.

关 键 词：混合式直流断路器 绝缘栅双极晶体管 IGBT 串联 动态均压 

分 类 号：TM561[电气工程—电器]