An SCR Inverter with an Integral Battery Charger for Electric Vehicles

A thyristor-based inverter/charger for use in electric passenger vehicles is described, and prototype charger test results are presented. A battery charger is included integral to the inverter by using a subset of the inverter power circuit components. The integral charger employs the inverter commutation components as a resonant ac/dc converter rated at 3.6 kW. The resulting charger provides electrical isolation between the vehicle propulsion battery and ac line and is capable of charging a 25-kWh propulsion battery in 8 h from a 220-V ac line. Charger efficiency and power factor at an output power of 3.6 kW are 86 and 95 percent, respectively. The inverter, when operated with a matching polyphase ac induction motor and nominal 132-V propulsion battery, can provide a peak shaft power of 34 kW (45 hp) during motoring operation and 45 kW (60 hp) during regeneration. Thyristors are employed for the inverter power switching devices and are arranged in an input-commutated topology. This configuration requires only two thyristors to commutate the six main inverter thyristors. The combined ac inverter/charger package weighs 47 kg (103 lb).