基于H-MMC风力发电系统无差拍电流控制策略

Deadbeat Current Control Strategy Based on H-MMC Wind Power System

提出了一种基于六边形模块化多电平变流器(hexagonal modular multilevel converter,H-MMC)的风力发电系统无差拍(deadbeat)电流控制策略。首先介绍了系统拓扑结构以及H-MMC的数学模型,得到了桥臂电压、桥臂电流的表达式。然后对机侧和网侧分别进行了控制,计算出机侧、网侧电流参考值以及环流和中性点电压参考值,从而计算出桥臂电流参考值,再对桥臂电流进行无差拍控制,计算出桥臂电压的参考值,并将其与最近电平逼近调制(nearest level modulation,NLM)相结合,得到每个子模块的控制信号。该控制方法具有控制简单、开关频率低,且不受机、网侧频率波动的影响等优点。最后在Matlab/Simulink中搭建了基于H-MMC的直驱式永磁风力发电系统模型,验证了所提控制方法的有效性。

This paper proposes a deadbeat current control strategy for wind power generation systems based on hexagonal modular multilevel converter(H-MMC).First,the system topology and the mathematical model of H-MMC are introduced,and the expressions of bridge arm voltage and bridge arm current are obtained.Then the machine side and grid side are controlled respectively,the machine side,grid side current reference value,circulating current and neutral point voltage reference value are calculated,thus the bridge arm current reference value is calculated,and then no difference in the bridge arm current Beat control is carried out,the reference value of the bridge arm voltage is calculated,combined with nearest level modulation(NLM),the control signal of each sub-module is obtained.The control method has the advantages of simple control,low switching frequency,and is not affected by frequency fluctuations on the machine and grid sides.Finally,a direct-drive permanent magnet wind power generation system model based on H-MMC is built in Matlab/Simulink to verify the effectiveness of the proposed control method.