基于LCL滤波的逆变器并网电流控制策略研究

Current Control Strategy for the Grid-connected Inverter with LCL Filter

LCL滤波器不仅电感量小,而且具有良好的高频衰减特性。但LCL滤波器为三阶系统,虽然能有效抑制并网电流中高次谐波电流,但却带来谐振问题。谐振问题对逆变器的控制策略提出较高要求。采用逆变器的逆变侧电流和并网侧电流双闭环控制方法,对基于PI调节和一种新型准PR(准比例谐振)调节的有源阻尼控制法进行建模及仿真。仿真结果表明,这种新型准PR调节的逆变侧和并网侧电流双闭环控制策略具有谐振抑制能力强、动态响应快等优点。

LCL-filter has a good high frequency attenuation characteristic with only a small inductance. The LCL filter is a third-order system, which can effectively restrain the grid-connected high harmonic current, but could lead to a resonance peak. The inverter side and grid side current double closed loop control method was adopted, modeled and simulated with PI and PR damping control method. Simulation results show that the inverter side and grid side current closed loop with the PR control strategy has a better harmonic suppression, and a quick dynamic response.