The control strategy of Harmonic suppression of Photovoltaic grid-connected inverter based on PI+MPR

In the field of grid-connected photovoltaic power generation, because the output PWM carrier of the inverter circuit is relatively low and the inverter circuit contains a large number of non-linear switching semiconductor devices, the three-phase grid-connected current is prone to distortion, which seriously affects the safe and reliable operation of the power system. The traditional PI current loop control is mostly used in the control system of the photovoltaic inverter circuit, although the control strategy can track quickly. Instruction current, but the ability to suppress harmonics is weak. Based on this, in order to suppress harmonic current and ensure good dynamic response, this paper proposes a harmonic suppression scheme of photovoltaic grid-connected inverters based on PI + proportional resonance control (MPR). By means of MATLAB/Simulink and experiments, it is proved that the scheme can not only improve the dynamic response performance of the system, but also reduce the specific sub-harmonics in the grid-connected current.