基于双重约束的并网逆变器电流自动化控制方法研究

esearch on Current Automation Control Method for Grid Connected Inverters Based on Dual Constraints

为降低并网逆变器逆变的并网电流畸变率,提出基于双重约束的并网逆变器电流自动化控制方法。以典型的三相LCL并网逆变器为例,分析其运行状态;并确定并网逆变器在进行逆变转换时,谐波对于逆变器并网电流的影响,计算并网逆变器环路增益函数;采用输出电流直接前馈的改进阻尼控制方法实现电流自动化控制,并引入全局-局部稳定双重约束原则,确定最佳的谐振抑制参数,提升电流的控制效果。测试结果显示,该方法的并网逆变器的电流畸变率均低于5%,电流跳变过程中,可在0.2 s内有效控制跳变电流结果。

In order to reduce the distortion rate of grid-connected inverter,an automatic control method of grid-connected inverter current based on double constraint is proposed.Taking a typical three-phase LCL grid-connected inverter as an example,the running state of the inverter is analyzed.The influence of harmonics on grid-connected current is determined and the loop gain function of grid-connected inverter is calculated.The improved damping control method of output current feedforward is adopted to realize automatic current control,and the double constraint principle of global-local stability is introduced to determine the best resonance suppression parameters and improve the control effect of current.The test results show that the current distortion rate of grid-connected inverters is lower than 5%.During the current jump process,the jump current result can be effectively controlled within 0.2 s.