单相光伏逆变器直流母线电压二次波动对系统影响的分析与抑制

摘要

基于传统双闭环控制策略的单相光伏并网逆变器会造成直流母线电压的二次波动,导致并网电流中含有三次谐波,影响输出电能质量.针对上述问题,在分析直流母线电压二次波动产生机理的基础上,文中提出一种在直流母线电压采样前加入周期积分器的双闭环控制策略.该控制策略能够消除因直流侧二次波动导致的并网电流三次谐波,有效抑制直流母线电压二次波动对系统输出电能质量造成的影响.仿真和实验验证了该方法的正确性与有效性.%In single-phase photovoltaic grid-connected inverter based on the conventional double closed-loop control strategy,the secondary voltage disturbances of DC bus will be generated,resulting in the triple harmonic of grid current,and affecting the quality of output energy.In view of these problems,based on analyzing the causes principle of the secondary voltage disturbances of DC bus,a double closed-loop control strategy increasing cycle integrator before DC bus voltage sampling is proposed in this paper.The strategy can remove the triple harmonic of grid current cased by the secondary voltage disturbances of DC bus,and then effectively suppress the effect on the quality of output energy.Simulation and experimental results are given to verify the rationality and effectiveness of the strategy.