基于有源阻尼的单相LCL并网逆变器改进电流控制器

为了提高LCL单相并网逆变器在电网频率波动情况下的控制精度,提出了一种采用比例、积分、谐振和准谐振复合控制环节的改进电流控制器。应用频率法对比例积分、比例谐振、准比例谐振以及改进电流控制器进行对比分析。结合传统比例积分控制器参数设计方法与权重系数获得合适的改进控制器参数,在所建立的基于有源阻尼的LCL单相并网逆变器仿真模型上对改进控制器与传统控制器进行实验对比。结果表明所提改进电流控制器克服了比例积分电流控制器无法实现并网电流无静差控制、比例谐振电流控制器对于电网频率变化鲁棒性很差以及比例准谐振控制器基波增益不够高的问题。

Improved Current Regulator of Single-phase Grid-connected Inverter with LCL Filter Based on Active Damping

To improve the control accuracy of a single-phase grid-connected inverter with LCL filter in the case of grid frequency fluctuations,an improved current controller composed of proportional,integral,resonant and quasi-resonant control links is proposed.Frequency method is adopted in the comparative analysis of proportional-integral,proportional-resonance,quasi-proportional-resonant,and the improved current controllers.The appropriate parameters of the improved current controller are obtained by combining the parameter design method for the traditional proportional-inte.gral controller with weight coefficients,and experimental comparisons of the improved controller with the traditional controllers are carried out on the simulation model of the LCL-type single-phase grid-connected inverter based on active damping.Simulation results show that the improved current controller can solve problems,such as the difficulty of the proportional-integral current controller in realizing zero steady-state error of grid-connected current,the poor robustness of the proportional-resonance current controller with respect to grid frequency,and the relatively lower fundamental wave gain of the proportional-quasi-resonant controller.