Integrated On-Board Battery Charger Based on Four-Bridge Converter

Integrated on-board battery chargers (IOBC) of electric vehicles make use of components from other on-board systems, typically from motor drive system. The integrated system reduces the weight, volume, and cost of the whole vehicle. In the proposed IOBC system, one bridge leg is added. The motor is regarded as inductor, and the traction inverter controls grid current while charging. Torque generated by the motor while charging can lead to noise or even mechanical damage, so the kernel of this design is how to reduce the motor torque to zero when the current flows through the motor during charging. By reasonably distributing the current of each phase, the proposed solution ensures zero motor torque while making full use of the motor inductance. Vehicle to grid (V2G) is also implementable on the proposed topology. The feasibility of the proposed IOBC is verified by simulation and experiment.