Pulse energy modulation of a single-phase transformer-less inverter with active decoupling

摘要

Single-phase inverters suffer from the double line frequency ripple problem. This paper presents a novel decoupling power control method that is applied to single-phase grid-connected photovoltaic systems. Based on pulse energy modulation, the proposed is direct control of the output and decoupling energy in every switching period rather than indirect control of current or voltage to eliminate the power difference between the input and output port of single-phase inverters. In this control method, there is no dc current sampling. Decoupling capacitor and the input voltage are independent of other system voltages. Decoupling capacitance reduction makes it possible to employ long lifespan film capacitor. The simulation results verify the valid of the proposed decoupling power control strategy.