A Simplified Single-Phase Integrated On-board Battery Charger with Low EMI Emission to Grid

Integrated charger (IC) uses motor drive and motor windings to construct the charger hardware, which could decrease the cost and volume of the energy conversion system in electric vehicles (EV) or plug-in hybrid electric vehicles (PHEV). However, the vibration torque of motor needs to be eliminated during charging. Furthermore, the additional devices for charger system should be minimized. In this paper, a simplified single-phase IC circuit topology is introduced. Meanwhile, a novel control and modulation scheme is proposed for the circuit. Compared to existed single-phase IC circuits, the introduced IC circuit does not need any additional hardware except a relay, the power level can be high enough benefiting from high power level of motor drive. And the motor is just a typical three-phase motor. The power flow can also be bidirectional, which is useful in vehicle-to-grid (V2G) technologies. Particularly, the common-mode electromagnetic interference (CM-EMI) to grid is eliminated a lot with the proposed modulation scheme, the switching losses are also reduced by half. Meanwhile, the vibration torque is controlled to zero instantly with the proposed control scheme. Experiment results verify the efficiency of the proposed IC system.