大功率IGCT高压变流器的研究

通过对大功率集成门极换向晶闸管（IGCT）高压变流器的结构、控制系统、保护系统的研究，设计出一套7.5 MVA的基于集成门极换向晶闸管的高压三电平中点箝位（NPC）变流器.通过对几种常见的三电平NPC变流器的拓扑结构进行研究，选取了采用分散的缓冲吸收电路的结构方式.控制系统采用基于VME总线的VMIC核心系统，利用信号数字处理（DSP）控制板生成三电平电压空间矢量PWM调制脉冲.保护系统可以对变流器运行中的过压、过流等各种故障采取快速有效的保护措施.在变流器系统的性能试验中，最大直流母线电压达到5 000 V ，最大输出电流达到2 500 A.试验结果表明，该变流器达到了7.5 MVA的设计要求.

Large power high voltage converter equipped with integrated gate commutated thyristors

Through analyzing the topology,control system and protection system of large power high voltage converter equipped with integrated gate commutated thyristor(IGCT),a set of 7.5 MVA three-level neutral point clamped(NPC)converter was designed.The converter uses a topology of separate snubber circuit.The control system adoptes a VME bus based VMIC core system and uses a digital signal processing board to generate three-level voltage space vector modulation pulse.The protection system can take fast and effective protection action aim at overvoltage or overcurrent or other faults.The converter performance experiment showed that the maximum direct voltage was 5 000 V,the maximum output current was 2 500 A,and the converter reached the 7.5 MVA design requirement and had excellent performance.