一种新颖的电压控制型逆变器并网控制方案

A Novel Control Scheme of Grid-connected Inverters Based on Voltage-controlled Mode

逆变器控制为电压源并网,其输出可直接供普通用户使用,相对于电流源并网,具有配置方便、无模式切换困扰等优点,但电流波形质量难以控制。针对这一缺陷,提出一种新颖的基于谐波电压重复控制的逆变器电压源型并网方案。通过快速谐波检测算法检测并网电抗两端的电压谐波,利用重复控制发出对应的谐波电压补偿电网谐波影响,减小并网电抗上的谐波电压差,达到降低并网电流总体谐波畸变率的目的。分析此方案的工作原理,设计控制器的关键参数和快速检测算法,并通过Matlab仿真和样机实验证明其有效性。

A grid-connected inverter based on voltage- controlled mode has an advantage of power supplying to common customers directly without mode-transition problems compared with that in current-controlled mode. However, because of the massive harmonic voltage in the grid, it＇s difficult for a voltage-controlled inverter to lower output current distortion to the criterion. This paper proposes a novel voltage-controlled scheme based on repetitive control and a quick harmonic detection algorithm, which detects harmonic voltage on the grid-connected inductance of an inverter and injects corresponding harmonic voltage to compensate existing harmonic. The principle is demonstrated and the design of the control scheme is discussed. The results of Matlab simulation and prototype experiments are presented to verify the validity of proposed theory.