Dual Mode BCM Control for Single-Phase Grid-Connected Inverter

A dual mode Boundary Conduction Mode (BCM) control is proposed to shrink the switching frequency and improve efficiency for a single-phase grid-connected inverter. By integrating bipolar triangular modulation and trapezoidal modulation over the entire line cycle, the maximum switching frequency could be reduced to be below 200 kHz. This approach improves the efficiency by 0.5% across the entire power range. The principle and design considerations of the method are presented. Experimental results from a 500 W prototype demonstrate the feasibility and effectiveness of the proposed approach.