Implementation of an integrated battery-charger for an electric-propulsion system

This paper proposes an integrated battery-charger for an electric-propulsion system. The system includes a rectifying diode bridge, an inverter, a motor, a digital signal processor, a battery set, and three relays. By suitably controlling the three relays and the switching states of the inverter, the proposed system can be operated either an electric propulsion system or a charger. Moreover, the charger can be operated as a boost converter or a buck converter. The input power factor is higher than 0.9, which can meet the IEC 1000-3-2 standard. Only three additional relays are required and the windings of the motor are connected. A digital signal processor, TMS-320-F-2808, is used to execute all of the control algorithms. As a result, the hardware circuit is quite simple. The volume and cost of the proposed system can be reduced when compared the traditional charger with a traditional propulsion system. Experimental results can validate the theoretical analysis and show the correctness and feasibility of the proposed method.