Presentation Description: In this presentation, A novel phase shift resonant converter control scheme, enabling an extended gain range, maintaining soft-switching across the entire load range is presented. This new control technique can be used in wide output voltage range applications, such as EV chargers where the output voltage range can vary by a factor of ~1:2. The control method, combines frequency modulation with primary and secondary phase shift control to be able to either increase or decrease the resonant converter gain. At very light load conditions, an additional commutation inductance is switched in parallel to the transformer primary to increase magnetizing current so that the in zero voltage switching (ZVS) operation can be extended. The converter operates in ZVS over entire load & line range with limited switching frequency variation, enabling high efficiency. The control method was implemented in a 1KW battery charger with an output voltage range from 190– 380 V using GaN switches on the power stage. The operating frequency range was restricted to 300 KHz – 500 KHz by the implementation of this control scheme; achieving ZVS even down to 10W output power. More than 97.5% peak efficiency was obtained at 1KW output power.
