Research On Single-phase ZVS Inverter With Active Power Decoupling

Power density is key index of residential PV inverter.Main factors that influence the power density of residential PV inverter are the limitation of switching frequency and the large volume of DC bus capacitors.Active Power Decoupling uses active components and energy storage capacitors to decouple the double-line power pulsation of single-phase inverter,while traditional method uses large electrolytic capacitors at DC side,and Active Power Decoupling can increase the power density of single-phase inverter.CAC ZVS inverters can realize ZVS switching of all switches,thus they can increase switching frequency and power density of inverters.Previous studies on CAC ZVS inverters are on three-phase and single-phase inverters.Up to now,there is no report on CAC ZVS single-phase inverter with Active Power Decoupling.In this paper,the circuit topology of CAC ZVS single-phase inverter with Active Power Decoupling is constructed.The ZVS-PWM modulation scheme is proposed.Operation stage analyze of the circuit is carried out and ZVS condition is derived.The real-time calculation method of short-circuit time is discussed.A prototype of 500 kHz switching frequency,1.5kW power rating ZVS single-phase inverter with Active Power Decoupling is designed and built.The operation waveforms are observed and compared with theoretical waveforms,to prove the theoretical analyzes.