Abstract:Because photovoltaic inverter and active filter have the same topology,the combination of photovoltaic inverter and active filter is conducive to improving the efficiency of photovoltaic grid-connected.Quasi proportional resonance (PR) control has strong dynamic response capability,but it can not achieve tracking without static error,while repetitive control can achieve tracking without static error,but there is delay problem and slow dynamic response.In this paper,PR control and repetitive control are combined to form a composite control to control the photovoltaic inverter,and realize the grid connection and filtering functions at the same time. The i_p-i_q harmonic detection method based on instantaneous reactive power theory is emphatically analyzed and simulated by MATLAB/Simulink software. The final simulation results show that the compound control can effectively suppress harmonics.