Series Resonant Converter With Multiple Resonant Points Using Sequential PWM for Electrical Vehicle On-Board Charger

In electric vehicle (EV) charging applications, maintaining high efficiency over a wide output voltage range is considered the most challenging mission. Pulse width modulation (PWM) controlled resonant converter can be a nice candidate, because its output voltage boosting capability is independent to the resonant tank components. However, it reveals its limitation showing efficiency drop between two resonant points. This paper proposes a resonant converter with “sequential PWM” achieving multiple resonant points while doubling the output voltage. The proposed converter significantly reduces turnoff loss and maximum resonant current by having multiple resonant points while doubling the output voltage. Accordingly, proposed converter maintains competitive high efficiency over a wide output voltage range.