基于比例谐振和谐波补偿控制技术的单相逆变并网研究

Research on Proportional-Resonant Controller and Harmonic Compensation for Grid-Connected Inverter

电网电压背景谐波的干扰在并网系统中是不可避免的,这会给并网电流带来大量的低阶谐波.提高开关频率能够抑制低阶谐波,却带来大量的高阶谐波.针对基于比例谐振控制(PR)和谐波补偿(HC)控制器的LCL型单相并网逆变器,详细分析了电流控制器参数对系统性能的影响,通过对并网电流的稳态误差、相位裕度和幅值裕度的分析得出满足要求的控制器各参数选择范围,结合系统的稳定性分析来选择控制器参数.仿真结果证明所给出的控制策略和参数设计方法是可行的.

The distortion of background harmonic voltage is inevitable in grid-connected system, which would result in serious low-order harmonics in the injected grid current. The low-order harmonics can be suppressed by increasing the switching frequency, while it also brings many high-order harmonics. Based on PR ＋ HC-based current controller, the effects of the current controller parameters on steady-state er-ror, phase margin and gain margin in LCL-type grid-connected inverter are investigated. A method is giv-en to obtain the controller parameters, region that meets the requirements, and the optimal parameters could be obtained on the basis of analysis in system stability. Simulation results verify the proposed con-trol scheme and parameters design method.