Bidirectional wide range and high voltage gain buck-boost DC-DC converter for EV chargers empowering V2G-G2V applications

This paper proposes a new wide range bidirectional buck-boost dc-dc converter with improved voltage gain in either forward (discharging) or backward (charging) direction for electric vehicle (EV) applications. The converter has high-voltage gain ratio with no theoretical limits in the output voltage in both directions, and presents a good balance between the component count, number of conducting components, semiconductor device ratings, having direct connection between input and output terminals, and efficiency which makes it a practical solution for the EV charger levels 1, 2, and 3 power converter unit. The operating principle, steady-state characteristics including the current and voltage stress of the switches, and comparison with other state of the art dc-dc bidirectional converters are explained in detail. In order to validate the theoretical analysis, a 500 W, 200 V or 40 V to 180 V laboratory prototype is implemented. The obtained results confirm the applicability of this structure and demonstrate a peak efficiency of 97.2% in the forward and 97.6% in the backward direction modes of operation. This paper proposes a new wide range bidirectional buck-boost dc-dc converter with improved voltage gain in either forward (discharging) or backward (charging) direction for electric vehicle (EV) applications. The converter has high-voltage gain ratio with no theoretical limits in the output voltage in both directions, and presents a good balance between the component count, number of conducting components, semiconductor device ratings, having common ground, and efficiency which makes it a practical solution for the EV charger levels 1, 2, and 3 power converter unit.image