T型三电平过载运行方法研究

Research on T-Type Three-Level Overload Operation Method

针对三电平T型变换器传统过载处理方法成本较高的问题,研究了一种新型的过载设计及其相应的控制方法。首先,介绍三电平T型变换器的工作原理。接着,针对过载条件下常规设计成本较高的问题,提出了一种三电平过载设计方法。该方法中:横排半导体器件组采用额定容量进行设计;竖排半导体器件组采用过载容量进行设计。然后,给出了过载运行的详细控制策略。当电流小于额定电流时,系统正常三电平运行。当电流大于额定电流且小于最大过载电流时,系统由竖排二管进行两电平运行。此外,为进一步提高系统过载模式下损耗性能,提出了一种替代解决方法。最后,通过仿真结果验证了理论的正确性。使用了该设计方法后,横排二管只需采用额定容量进行设计,而竖排器件仍采用过载容量进行设计。这可以大幅降低系统成本。

Aiming at the problem of high cost of traditional overload processing method of three-level T-type converter,a novel overload design and its corresponding control method are studied.Firstly,the working principle of three-level T-type converter is introduced.Then,a three-level overload design method is proposed to address the problem of high cost of conventional design under overload conditions.In this method:the horizontal row semiconductor device group is designed using the rated capacity;the vertical row semiconductor device group is designed using the overload capacity.Then,a detailed control strategy for overload operation is given.When the current is less than the rated current,the system operates normally at three-level.When the current is larger than the rated current and smaller than the maximum overload current,the system is operated in two-level by the vertical row of two tubes.In addition,an alternative solution is proposed to further improve the loss performance of the system in overload mode.Finally,the correctness of the theory is verified by simulation results.With the use of this design method,the horizontal row of two tubes need only be designed with rated capacity,while the vertical row of devices is still designed with overload capacity.This can significantly reduce the system cost.