二极管钳位型MMC电路的均压控制策略

Voltage Sharing Control Strategy of Diode Clamped MMC Circuit

为解决传统模块化多电平换流器(modular multilevel converter,MMC)均压系统中直流电压传感器较多、控制电路复杂的问题,将二极管钳位拓扑应用到MMC中,并提出了适用于该拓扑的电容电压均衡控制方法。该拓扑通过在各子模块电容正极加装钳位二极管,为直流电容提供单向钳位通路,从而实现MMC各桥臂子模块电容电压从上到下依次减小,简化了系统电路及其控制方法。最后,在MATLAB/SIMULINK平台上搭建了11电平二极管钳位型M M C拓扑仿真模型,结果表明该拓扑具有电容电压自排序功能,电容电压均衡效果良好。

To solve the problem that the traditional modular multilevel converter （MMC） voltage balancing system contains more DC voltage sensors and complicated control circuit, this paper applies the diode clamped topology into the MMC, and puts forward the suitable capacitor voltage balance control method for this topology. This topology can provide one-way clamp path for the DC capacitor by installing clamp diodes in each sub module capacitor anode, so as to reduce the sub module capacitor voltage of each bridge arm in MMC from top to bottom in turn, and simplify the system circuit and its control method. Finally, we build the eleven level diode clamped MMC topology simulation model in MATLAB/ SIMULINK. The results show that the topology has the self ordering function and good balance effect of the capacitor voltage.