Harmonic compensation method of grid-tied converters in a weak grid

In this paper, a control strategy is proposed to compensate the voltage of point of common coupling (PCC) voltage and grid current harmonic by using line end grid connected inverter. The control strategy uses the current and voltage information at the outlet of the inverter and indirectly calculates the voltage at the PCC in conjunction with the network equation. The voltage loop adopts proportional and parallel resonant regulators to control the harmonic of the selected voltage, and the current loop adopts proportional integral and parallel resonant regulator to control the output current of the inverter, It realizes the compensation of active power injection and PCC voltage and current harmonic in the distributed generation system, and saves the investment of installing additional measurement devices and long-distance information communication at PCC. The simulation results based on Matlab verify the correctness of the proposed control strategy.