电网电压谐波对并网逆变器输出电流质量的影响及改进控制策略研究

Study of Influence of Grid Voltage and Harmonics on Output Current Quality of Grid Connected Inverter and Improved Control Strategy

本文基于可再生能源并网发电系统公共耦合点电压存在背景谐波,建立了并网逆变器的等效电路模型,解析了公共耦合点处电压背景谐波影响并网逆变器输出电流的机理,在控制环路中引入多谐振控制器改善了并网逆变器的输出电能质量,并给出了一种多谐振控制器参数设计的方法。最后,在仿真软件中搭建了可再生能源发电系统和配电网的模型,设定了电网背景谐波参数,分别进行了有无多谐振控制器控制策略的仿真实验,实验结果验证了本文采用的控制策略的正确性和可行性。

In this paper,the equivalent circuit model of grid-connected inverter is established with considering the background harmonics of common coupling point voltage in renewable generation system. The mechanism of the influence of voltage background harmonics at common coupling point on the output current of grid-connected inverter is analyzed. A multi-resonant controller is introduced into the control loop to improve the output power quality of grid-connected inverter. Parameter design method of multi-resonant controller is given. Finally,the model of renewable energy generation system and distribution network is built in the simulation software,and the background harmonic parameters are set. The simulation experiments of the control strategy with or without multi-resonant controller are carried out respectively. The correctness and feasibility of the control strategy used in this paper is verified by the experimental result.