大功率IGBT模块软关断短路保护策略

Soft Turn-off Short-circuit Protection Strategy Applied to High Power IGBT Module

大功率绝缘栅双极晶体管(IGBT)模块在电力电子设备中的运用越来越广泛,其对驱动器的性能要求也越来越高。IGBT可以承受短路的时间非常短,短路时最大电流远远超过额定值,单位时间功耗也远远高于正常工作状态,且直接关断IGBT会产生非常高的关断尖峰电压。提出缓慢降低IGBT门级电压的软关断策略,驱动器检测到IGBT短路后用0 V驱动电压立即执行软关断动作,当电流降到一定值后再使用负压正常关断。此策略可以使驱动器更早地采取保护措施,限制IGBT短路电流,减小IGBT短路功耗并控制关断尖峰电压。硬关断策略短路保护实验和软关断策略短路保护实验的结果对比验证了软关断策略的优势。

The application of high power IGBT module in power electronic apparatus becomes more widespread and the requirement for the driver is improved either. IGBT could withstand short-circuit state only in a very short period because maximum current is far greater than rated current in short-circuit condition and power consume is much more than which is under normal working condition. Moreover, a very high spike voltage will occur if IGBT is shut down directly under short-circuit. A strategy of soft turn-off was presentd which enables the driver to take protective measures earlier and this could bring limited short-circuit current, smaller short-circuit power consume and lower spike voltage. The contrast between hard and soft turn-off short-circuit protection experiments demonstrate the advantage of the soft one.