Research on control of two-stage three-phase photovoltaic grid-connected inverter

The variable-step incremental conductance method with the introduction of a power prediction link is proposed to address the problem of low light energy utilization and large distortion of grid-connected current in two-stage photovoltaic grid-connected inverters. This control method can optimize the positive dynamic speed and tracking accuracy of the maximum power point tracking control (MPPT). The coupling relationship under the dq synchronous rotation coordinate system and the influence are analyzed depending on the mathematical model of inverter-side photovoltaic grid connection. The grid-connected control adopts a voltage and current double closed-loop control method. A simulation model of the two-stage three-phase photovoltaic grid-connected inverter is constructed and studied in Matlab/Simulink. The simulation results show that the control method has fast response speed and small distortion of grid connected current waveform, which demonstrates the correctness of the control method.