基于滑动平均算法的模块化多电平变换器解耦控制策略

Decoupled Control Strategy of Modular Multilevel Converter Based on Moving Average Algorithm

模块化多电平变换器(MMC)是一种具有诸多优势的电力电子变换器。然而,由于MMC的结构特点,子模块电容会周期性进行充放电,因此子模块电容电压会不可避免地出现波动,而电容电压纹波会使MMC输出电压恶化,总谐波畸变率(THD)升高。针对该问题,提出了一种基于滑动平均算法的电容电压解耦控制策略。采用所提策略,不仅子模块电容电压可达到较好的平衡效果,还能消除子模块电容电压纹波对输出电压的影响。通过仿真和实验,验证了所提方法的有效性。

Modular multilevel converter(MMC)is a power electronic converter with many advantages.However,due to the structural characteristics of the MMC,the submodule capacitor will be charged and discharged periodically,so the voltage of the submodule capacitor will inevitably fluctuate.Therefore,the ripple of capacitor voltage will worsen the MMC output voltage and increase the total harmonic distortion(THD).Aiming at this problem,a capacitorvoltage decoupling control strategy based on the moving average algorithm is proposed in this paper.The proposed strategy can not only achieve a better balance of the submodule capacitor voltage,but also eliminate the influence of the submodule capacitor voltage ripple on the output voltage.The effectiveness of the proposed method is verified by simulation and experiments.