Patent ID: 6236172
Filing Date: 2001-05-22
Classification: B60L,Y02T

Abstract:
Apparatus for driving an electric vehicle, comprising:a permanent-magnet type synchronous traction motorsa battery;an inverter for converting DC electric power from the battery into AC electric power which is supplied to the synchronous motor;a smoothing capacitor connected in parallel to the inverter for smoothing the AC electric power; anda PSM control unit for performing ON-OFF control of a plurality of power switching elements composing said inverter based on a torque reference and a motor current;wherein an induced electromotive force of said synchronous motor is set so that a peak value V.sub.0max of the maximum induced electromotive force at a maximum allowable rotating speed N.sub.2 of said synchronous motor satisfies the condition V.sub.0max.ltoreq.V.sub.Cmax, V.sub.Cmax being an allowable voltage of said smoothing capacitor; andwherein V.sub.0 obtained by the following equation satisfies said condition of V.sub.0max :V.sub.0 =2v.sub.0.multidot..alpha.V.sub.0 being an effective value of the induced electromotive force, and .alpha. being a peaking ratio, taking slot ripples into consideration.