如何在三电平技术的基础上提高逆变器额定电压到6kV

How to Increase Inverter Rated Voltage up to 6 kV Based on Three-level Technology

三电平中压变频器有许多优点,但在国内的竞争中却屡屡败于H桥级联变频器,主要的原因是输出电压达不到6kV(不满足国标要求)和dV/dt高(需要加强绝缘),导致电动机特殊。如何在三电平技术的基础上提高逆变器额定输出电压到6kV是一个困扰开发三电平变频器技术人员多年的难题。在回顾现有解决方案基础上,介绍一个新方法定子绕组联线打开、两套公用直流母线的三电平逆变器串联方案。它保留了三电平变频的优点,克服了它的缺点。

Three-level medium-voltage inverters have many advantages, but lose competitions with cascaded H-bridge inverters often in China. The main reason is that the rated voltage of this kind of inverters can not reach 6 kV （does not meet the requirement of Chinese standard） and its dV/dt is high（asking for higher level isolation） ,which make motor nonstandard. How to increase inverter rated voltage up to 6 kV based on three- level technology is a problem which is puzzled engineers for a long time. Based on a review of existed solutions,a new scheme,opening stator winding connection and connecting two three-level inverters with common DC-bus in series,is investigated. The new one reserves the advantages of three-level inverters and overcome their shortages.