Hybrid ZVS BCM Current Controlled Three-Phase Microinverter

This paper presents a new zero-voltage switching (ZVS) control method that is suitable for low-power applications such as three-phase microinverters. The proposed hybrid control method increases the efficiency and power density of the microinverters and features both reduced number of components and easy digital implementation. ZVS is achieved by controlling the inductor current bidirectional in every switching cycle and results in lower switching losses, higher operating frequency, and reduced size and cost of passive components, especially magnetic cores. A 400 W prototype of a three-phase inverter and its hybrid control system have been designed and tested under different conditions to verify the effectiveness of the controller. Efficiency measurement and comparison of the three different current modulation schemes have been conducted, and the inverter exhibits peak efficiency of 98.4% with fixed reverse current boundary conduction mode modulation.