Use of traction inverter for supplying power for non-traction

Abstract

A method and apparatus for cranking of an internal combustion engine in an AC electric traction motor propelled vehicle using inverters normally coupled to supply power to each of a plurality of AC motors. The inverters have DC input terminals connected between a relatively positive DC bus and a relatively negative DC bus and the DC buses are connected to DC output terminals of a rectifier. The rectifier has AC input terminals connected to stator terminals of a synchronous generator. The generator includes a field winding and a rotor connected in driving relationship to a crank shaft of the engine. The vehicle further includes switching apparatus for selectively connecting a battery to the positive and negative DC buses and for disconnecting at least one of the inverters from the AC motor and connecting the at least one of the inverters to supply power to the generator such that the at least one of the inverters is operable to energize the generator whereby the generator operates in a motoring mode to rotate the engine crank shaft to start the engine. Another of the inverters is separately connectable to a pre-lube pump motor for effecting lubrication of the engine prior to starting the engine. After lubricating and starting of the engine, the switch reconnects the inverters to supply AC electric power to respective traction motors of the vehicle.