A controller design of quick chargers with a current offset compensator

This paper proposes a controller design of quick battery chargers for electric vehicles with a current offset. The quick charger consists of a three-phase grid connected inverter and a full-bridge converter which use the phase-shift switching method. The 3-phase inverter controls the input and DC-link voltage by use of a current controller and a DC-link voltage controller. The full-bridge converter transfers the DC-link voltage to a fixed output voltage. The system and controller design of the quick charger are proposed in this paper. Furthermore, the paper proposes a compensation method for the offset current that is caused by switch failure and circuit problems. Simulations have been performed on a 50kW-battery charger system that is suitable for vehicles. The presented results verify the validity of the proposed method.