不平衡电压下交、直流混合微电网直流纹波抑制策略

DC ripple suppression strategy for AC/DC hybrid microgrid under unbalanced voltage

交、直流混合微电网中,由于交流子网不平衡,使直流子网存在2倍频的直流纹波,文章提出一种直流电压纹波抑制策略。首先,在换流器控制层面,使用负序分量补偿控制,抑制交流子网不平衡对直流侧造成的2倍频脉动;其次,在交、直流混合微电网直流侧,使用基于准比例谐振控制器(Quasi Proportional Resonant Controller,QPR)改进的直流有源滤波器(Active Power Filter,DC-APF)来精准地跟踪直流侧2倍频脉动,以直流电压稳定为控制目标,交、直流协同控制;最后,Matlab/Simulink仿真结果表明,所提控制策略的直流电压纹波含量比传统控制方法低4倍左右,可以有效地抑制交、直流混合微电网直流侧母线电压二次纹波和有功功率波动。

In AC/DC hybrid microgrid,due to the unbalance of AC subnet,the DC subnet has double frequency ripple.This paper presents a DC voltage ripple suppression strategy.Firstly,at the converter control level,the negative sequence component compensation control is used to suppress the double frequency pulsation caused by the unbalanced AC subnet on the DC side.Secondly,on the DC side of the AC and DC hybrid microgrid,an improved DC active power filter(Active Power Filter,DC—APF)based on Quasi proportional Resonant Controller(Quasi proportional Resonant Controller QPR)is used to accurately track the double—frequency pulsation of the DC side.With the stability of the DC voltage as the control target,the AC and DC coordinated control;finally,Matlab/Simulink simulation results show that the DC voltage ripple content of the proposed control strategy is about 4 times lower than that of the traditional control method,which can effectively suppress the secondary ripple and active power fluctuation of the DC side bus voltage of the AC and DC hybrid microgrid.