曹筱欧+郑凤柱+刘金华+李峥铮

摘 要： 并网逆变器在以光伏发电为电力来源的分布式供电系统中起到关键的连接作用，其可将光伏阵列所发电能逆变为与电力网络电压频率相同、相位一致的电压与电流保证光伏发电系统和电力网络正常运行。但传统并网逆变器存在共模漏电流严重，中点电位二次脉动以及转换电压二次谐波含量较多的问题。为改善并网逆变器的逆变性能，设计一种新型无隔离变压器结构的单相逆变器。分析新型并网逆变器直流变换电路模块和直流交流变换电路模块的工作机理，并将其与传统并网逆变器对光伏阵列所产生的电平处理效果进行仿真比较，结果表明，新型逆变器输出逆变电压二次谐波含量较传统逆变器降低54.87%，具有较好的逆变功能。

关键词： 分布式供电； 光伏阵列； 并网逆变器； 二次谐波

中图分类号： TN711?34； TN911 文献标识码： A 文章编号： 1004?373X（2017）08?0180?03

Research on new type photovoltaic grid?connected inverter in distributed

power supply network

CAO Xiaoou1， ZHENG Fengzhu2， LIU Jinhua1， LI Zhengzheng2

（1. Binhai Power Supply Subsidiary Company， State Grid Tianjin Electric Power Company， Tianjin 300450， China；

2. Beijing Guodiantong Network Technology Co.， Ltd.， Beijing 100070， China）

Abstract： The grid?connected inverter plays a key connection role in the distributed power supply system taking the photovoltaic power generation as the electric power source， which can invert the electric power generated by the photovoltaic array into the voltage and current which have the same frequency and same phase with the electric power network voltage， so as to guarantee the normal operation of the photovoltaic power generation system and electric power network. Since the traditional grid?connected inverter has the problems of serious common?mode leakage current， secondary pulsation of the neutral point potential and too much secondary harmonic content of the conversion voltage， a new type single?phase inverter without isolation transformer structure was designed to improve the invertion performance of the grid?connected inverter. The working mechanisms of the DC converting circuit and DC?AC converting circuit modules of the new type grid?connected inverter are analyzed. The voltage processing effect of the new type grid?connected inverter on the photovoltaic array is compared with that of the traditional one by the simulation mode. The result shows that the secondary harmonic content of the output inverting voltage of the new type inverter is decreased by 54.87%. The inverter has good invertion function.

Keywords： distributed power supply； photovoltaic array； grid?connected inverter； second harmonic

0 引 言

并网逆变器在光伏并网电力系统中发挥着重要作用，其在光伏发电系统和新能源电力网络之间起到关键的连接作用。光伏发电系统产生直流电能，无法直接为电力网络供电，需要将其逆变为与电力网络电压频率相同、相位一致的电压与电流。由此，光伏发电系统和电力网络才能正常运行。传统并网逆变器存在共模漏电流严重，中点电位二次脉动的问题，转换电压二次谐波含量较多，为改善并网逆变器的性能，本文设计了一种无隔离变压器结构的单相逆变器，改善当前并网逆变器的性能。……