Nonlinear research of single-phase photovoltaic grid-connected inverter with quasi PR controller

Taking the quasi PR controller single-phase LCL photovoltaic grid-connected inverter as the research object, the discrete iterative model of the system is derived by using the stroboscopic mapping method. Through bifurcation diagram and Matlab/Simulink simulation, the evolution process of the system from stable state to chaotic state with the change of circuit parameters is described. The Jacobian matrix method is used to analyze the stability of the system, and the stable working regions of the system under two bifurcation parameters and three bifurcation parameters are obtained. According to the eigenvalues of Jacobian matrix under different parameters, the bifurcation type and the oscillation frequency after instability are determined. Finally, the real-time waveform of grid-current is obtained through physical experiments, which further verifies the correctness of the theoretical analysis. © 2022, Solar Energy Periodical Office Co., Ltd. All right reserved.