A novel Multi-functional photovoltaic Micro-inverter and its control strategy

摘要

A Multi-functional photovoltaic Micro-inverter (MFMI) can provide active power and slightly compensate the harmonic current of the grid at the same time. As MFMI implements distributed harmonic suppression in both low voltage distribution network and distributed generation, it has a good prospect. In this paper, a novel control strategy of MFMI is analyzed. Since the MFMI works in discontinuous conduction mode (DCM), the peak current control method is proposed to achieve open-loop control. More importantly, there is a droop characteristic established between the total harmonic distortion (THD) current and MFMI's unused volume. So the droop control is applied to generate the compensation current reference, which balance the compensation current of several MFMIs without communication. The design and control methodology are validated by simulation results with Matlab Simulink.