基于改进调制的两级式单相光伏并网逆变器前级二次谐波抑制  

Front-stage second harmonic suppression of a two-stage single-phase photovoltaic grid-connected inverter based on improved modulation

作　　者：张鸿博[1] 熊军华[1] 李继方 ZHANG Hongbo;XIONG Junhua;LI Jifang(College of Electrical Engineering,North China University of Water Resources and Electric Power,Zhengzhou 450045,China)

机构地区：[1]华北水利水电大学电气工程学院,河南郑州450045

出　　处：《电力系统保护与控制》2023年第17期110-118,共9页Power System Protection and Control

基　　金：河南省科技攻关计划项目资助(222102240072);河南省高等学校重点科研项目计划支持(17A470011)。

摘　　要：为抑制两级式单相光伏并网逆变器前级电路中的二次谐波电流,利用开关周期平均模型对前级电路中二次谐波电流产生的原因进行了分析,基于此提出了抑制二次谐波电流的改进调制方法。该方法根据实时采样得到的母线电压修正占空比,无需复杂的运算处理,易于实现。进一步分析了改进调制方法下前级Boost电路的小信号传递函数,提出了欠阻尼条件下基于微分先行PID算法的光伏电池最大功率点电压跟踪方法。仿真表明,改进后的两级式单相光伏并网逆变器最大功率点跟踪过程振荡小,光伏电池输出电流平稳,二次谐波电流抑制效果显著。To suppress the second harmonic current in the front-stage circuit of a two-stage single-phase photovoltaic grid-connected inverter,the causes of the second harmonic current in the front-stage circuit are analyzed using a switching period average model,and based on this an improved modulation method for suppressing the second harmonic current is proposed.This method corrects the duty ratio according to the bus voltage obtained by real-time sampling.This is easy to realize without complicated processing.The small signal transfer function of the front-stage Boost circuit using an improved modulation method is analyzed,and a voltage tracking method of the maximum power point of photovoltaic cells based on a differential ahead PID control algorithm in an under-damped condition is proposed.The simulation results show that the improved two-stage single-phase photovoltaic grid-connected inverter has little oscillation in the maximum power point tracking process,the output current of photovoltaic cells is stable,and the second harmonic current suppression effect is remarkable.

关 键 词：并网逆变器 二次谐波 抑制 开关周期平均 调制 

分 类 号：TM464[电气工程—电器]