LCL滤波单相并网逆变器电流加权控制研究

Research on LCL Filter Weighted Current Control for Single- Phase Grid- Connected Inverter

针对并网逆变器LCL滤波器直接电流控制出现的稳定性和控制精度等问题,提出了一种电流加权控制的策略。控制方案采用逆变器侧和电网侧电流加权反馈方式,调节电流反馈系数可以改善系统性能,还分析了电网电感对控制策略的影响。为了验证理论的正确性和控制策略的有效性,在Matlab/Simulink中搭建额定功率5kW的LCL加权电流控制仿真系统。仿真结果表明,电流加权控制稳定裕度大稳态精度高,馈入电网电流总体谐波畸变率小,功率因数高;另外,电网阻抗增大时不影响系统的稳定性,入网电流谐波却进一步下降,功率因数也略有下降。

Aiming at the problem of stability and control accuracy in direct current control for grid -connected inverter LCL filter, a weighted current control strategy has been presented in this paper .The control scheme adopted an invert-er side current and grid side current as feedback signal to improve the system performance by adjusting the feedback parameters.The influence on control strategy by grid inductance has been analyzed .A rated power with 5kW LCL weighted current control simulation system has been built by Matlab /Simulink to verify the correctness of the theory and the control strategy.The simulation results show that, the current weighted control will have high stability margin and steady state accuracy, grid current total harmonic distortion rate will be very low ,and the power factor will be ver -y high.In addition, the increasing grid impedance will not affect the stability of the system ,but the current harmonic will be further reduced, and the power factor will be lower.