A new quasi resonant DC link for single phase micro inverter

A new quasi resonant DC link that allows for pulse-width-modulation (PWM) is presented in this paper. The proposed quasi resonant DC link provides zero-voltage switching (ZVS) condition for the main devices by resonating the DC-link voltage to zero via three auxiliary switches and LC components. The operating principle and mode analysis are given. The simulation was carried out to verify the proposed soft switching technique. A 150W 120VAC single-phase prototype was built. The experimental results show that the soft switching for four main switches can be realized under different load conditions and the peak efficiency can reach 95.6%.The proposed quasi DC link can be applied to both single-phase and three-phase DC/AC micro inverter.