An Interleaved Bridgeless Single-Stage AC/DC Converter With Stacked Switches Configurations and Soft-Switching Operation for High-Voltage EV Battery Systems

A novel single-stage ac/dc isolated onboard charger with modular stacked switches structure utilizing interleaved control is proposed in this article for high-voltage (HV) battery systems in electric vehicles (EVs). In the proposed converter, modular interleaved bridgeless ac/dc boost converters are integrated with modular CLL resonant circuits through sharing the two legs of stacked switches. With this configuration, the voltage stress across each switch is reduced to half of the dc-link voltage, which makes the circuit applicable for HV battery system (such as 800 V) in EVs. In the proposed design, the integrated interleaved boost circuit modules allow low input current ripple to be achieved. Two step-up resonant circuit modules are then connected to the two interleaved legs with their outputs connected in series at the input of a current-fed high-frequency rectifier. Soft-switching commutation is achieved for all switches and diodes in the proposed converter. The descriptions of the proposed converter and its operating principles will be discussed in this article. A silicon-carbide-based hardware prototype with a rated power of 2.4 kW, 90–135 Vac/800 Vdc system has been tested in the laboratory. Results confirmed that a power factor of 0.97 and a peak efficiency of 97.9% were achieved.