分布式发电系统中并网逆变器的新型有源阻尼策略

A Novel Active Damping Control Scheme for Grid-connected Inverter in Distributed Power Generation Systems

分布式发电系统中LCL型并网逆变器可以有效抑制高频谐波,但存在谐振峰,会导致系统不稳定。因此采用电压或电流反馈的有源阻尼方法引起广泛关注,但这些方法需要多个传感器,增加了成本和控制复杂度。为此,采用二阶陷波器抑制LCL滤波器的谐振峰,保证系统稳定。根据LCL滤波器的谐振频率,设计了二阶陷波器参数,提高系统稳定性。通过选择合适的陷波器品质因数,增强系统应对电网电感变化的鲁棒性。采用比例—积分控制器增加基频增益,减小了系统稳态误差和提高了动态响应速度。仿真和实验验证了所提方法的正确性。

The grid-connected inverter with LCL filter in the distributed power generation system (DPGS) has the ability of attenuating high frequency current harmonics.However,the resonance of LCL filter will lead to instability of the system.In order to avoid stability problems,some active damping techniques for voltage or current feedback are adopted.But these methods need extra sensors and increase control complexity.A notch filter provides an effective solution and can ensure the stability.A new designed notch filter is proposed to neutralize the resonance of LCL filter and a proportional-integral (PI) controller is employed to increase the gain of fundamental frequency for reducing steady-state errors and improving the dynamic response.The analysis is validated by simulation and experiment.