基于PI调节器和电容电流反馈有源阻尼的LCL型并网逆变器闭环参数设计

基于电容电流反馈的有源阻尼是实现LCL型并网逆变器谐振峰阻尼的一种有效方法,PI调节器因其简单有效而常用于并网电流的控制。针对基于PI调节器和电容电流反馈有源阻尼的LCL型单相并网逆变器,详细分析PI调节器参数和电容电流反馈系数等闭环参数对系统性能的影响,通过对并网电流稳态误差、系统相位裕度和幅值裕度的分析,得到满足上述要求的PI调节器参数和电容电流反馈系数的取值范围,结合实际应用需要就可从中优化选取出合适的闭环参数。所提出的闭环参数设计方法不需要反复试凑,不仅可以有效阻尼LCL滤波器谐振峰,而且可以使系统具有高鲁棒性、快速动态响应性能和低稳态误差。实验结果证明了所提出的闭环参数设计方法是有效的。

Design of Grid-connected Inverters With LCL Filter Based on PI Regulator and Capacitor Current Feedback Active Damping

The active damping based on capacitor current feedback is an effective way to damp the resonance caused by the LCL filter in the grid-connected inverters.Besides,PI regulator is widely used to control the injected grid current for its simplicity and effectiveness.Based on the PI-based injected grid current regulator and capacitor-current-feedback active damping,the effects of the controller parameters on the specific requirements of the LCL-type grid-connected inverter,i.e.,steady-state error,phase margin,and gain margin,were investigated in this paper.A step-by-step method was proposed to obtain the entire parameter regions that meet the requirements aforementioned.Based on these parameter regions and specific application requirements,the appropriate injected grid current regulator and feedback coefficient of capacitor current could be obtained without try and error procedure.The proposed method can yield a proper controller which ensures effectively damped,highly robust,fast transient-response and low steady-state-error system.Experimental results verify the effectiveness of the proposed design method.