Three Phase High Power Integrated Battery Charger for Plugin Electric Vehicles

Battery chargers for plugin electric vehicles can be costly and add to the weight and volume of the vehicle when designed to be on-board. Conversely, integrated battery chargers not only re-use the already available components on-board but also provide a higher charging power capability than their dedicated counterparts. Such chargers use the traction motor´s windings as input filter when connected to the three-phase supply. Surface mounted permanent magnet motors have not been used for integrated battery chargers for the apparent risk of rotor movement while charging. This paper demonstrates the use of a surface mounted permanent magnet motor to charge the battery while identifying the limiting factors of its implementation. The maximum torque (70Nm) developed on the rotor while charging is calculated using an FEA model of the motor and is found to be within the limits that a vehicle can withstand. Efficiencies up to 97% with an acceptable THD was achieved with a scaled down power version of the charger.