Capacitor Current Compensation for BCM based Single-Phase Grid-Connected Inverter

Boundary conduction mode (BCM) can be employed in single-phase grid-connected inverters to enhance the efficiency due to its soft-switching feature. The average current of the inductor is controlled to follow a sinusoidal reference. However, the presence of the output capacitor current introduces a phase lag between the grid current and grid voltage. This paper proposes a compensation method to make the grid current and voltage in phase by compensating for the capacitor current to the reference current without any auxiliary components. This method has no influence on the ZVS conditions, dynamics as well as on the efficiency. Experimental results for a 500 W prototype are provided to validate the feasibility and effectiveness of the proposed method.