A Control Scheme for Integrated Battery Charger With Split-Phase Machine

Abstract

One of the main challenges in Electric Vehicle (EV) technology is to make its on board battery charger light and effective. Integrated Battery Chargers (IBCs) provide a viable solution since it uses the existing driving motor and driving inverter in the EV to charge the battery. IBCs using split-phase machines is an upcoming topology that has the advantage of using the existing three-phase inverter of the electric vehicle. The split phase machine windings are configured to run as three phase motor during driving mode and are reconfigured during charging to produce a pulsating magnetic field, thereby producing zero torque. The presence of pulsating magnetic field on the asymmetric winding structure of the split phase machine makes the grid-interface impedance unbalanced, injecting harmonics in the grid current. In this paper the control of IBC using feedforward terms and harmonics rejection is implemented to reduce the harmonics in the grid currents. The feed-forward terms are found from the synchronous reference frame model of the IBC with the split-phase machine. PI and PR controllers with feedforward terms are used for harmonic rejection. Experimental results are included for validation of the proposed control technique.