模块化多电平换流器子模块故障快速诊断方法

为了提高模块化多电平换流器(MMC)的可靠性,当故障发生后,需要迅速检测并定位子模块故障。分析了故障诊断存在的快速性问题,提出了一种快速的故障诊断方法。故障检测采用基于改进的预测模型的方法,通过比较桥臂电流预测值与测量值的差值是否大于阈值来判断故障,故障定位采用比较子模块电容电压斜率的方法来判断故障,可以快速地定位多个子模块故障,且无需外加传感器,结构简单易实现。最后,搭建了MMC仿真和实验平台,验证了该方法的可行性。

Rapid Diagnostic Method for Submodule Failure in Modular Multilevel Converter

To improve the reliability of modular multilevel converter(MMC), the submodule failure should be detected and located rapidly when fault occurs. The speed characteristics of fault diagnosis are analyzed during submodule failure in the MMC. A new rapid diagnostic method for fault is proposed. For fault detection, the improved model predictive method is used to detect the fault by comparing the difference between the predictive value and the measured value with the threshold value and then the failures are located rapidly by comparing the slopes of submodule voltage. The proposed method can locate multiple submodule failures without additional sensors and can easily be implemented with the use of a microprocessor. Finally, the proposed method has been validated by the results of an MMC simulation and experiment platform.