AN IMPROVED CONTROL METHOD OF PHASE COMPENSATION FOR PHOTOVOLTAIC GRID-CONNECTED INVERTER

Shengqing Li, Yuwen Zhang, Yao Ming, and Wenfeng Wu

Keywords

Phase compensation, high-frequency inverter, closed-loop control, feed forward factor

Abstract

Photovoltaic grid-connected inverter has a core position in the grid-connected photovoltaic system and its control effect affects the level of automation in the whole power system. We proposed an improved control method of phase compensation for the photovoltaic grid-connected inverter, adding feedforward grid voltage and then designing feedforward factor so as to eliminate the disturbance component which is caused by the nonlinear load in the actual power grid. Regarding the half wave current of the filter inductor as the feedback of the current closed-loop control, and reverse the half sine wave to full sine wave through amplitude reverse function, and then minus the reference current value. The deviation is regarded as the parameter of the main circuit of the inverter, and the phase deviation in the system is eliminated. It synchronizes the phase of grid-connected current and voltage and significantly reduces the harmonic current automatically. Finally, the simulations and experiments are given to illustrate the obtained theoretical results.

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