Time Based Adaptive Scheme for SiC-Based Totem Pole PFC and FBLLC Stage for Portable EV Charger Design with G2V/V2X Compatibility

The design of totem pole PFC (Power Factor Correction) stage for EV charger needs wide variation in switching frequency. This is due to wide regulation in an intermediate DC link. This leads to lose of ZVS margin. For this, an analytical model of totem pole PFC stage is designed. It is based on high frequency PWM turn-off current. This sensed quantity is used to extend ZVS margin. This control degree of freedom regulates needed reactive energy to achieve ZVS over any variation in the DC link voltage reference. This action reduces complete range of switching frequency. The ZVS margin in FBLLC stage is controlled by controlling a shift of rising edge need to discharge the incoming MOSFET. It is needed at light loading scenario when reactive energy is not sufficient to achieve ZVS. It is designed based on mathematical expression presented. A hybrid intermediate DC link approach is utilized for wide battery voltage. A modified pre-filtering stage with adaptive fixed frequency SOGI is utilized for grid angle estimation under worst grid scenarios. A 3.3 kW system is designed to validate designed control over multiple grid and loading scenarios.