Electric drive transmission systems

Claim 1

A car having a battery, a solid state inverter connected to receive direct current from said battery, an induction motor supplied with alternating current from the inverter, drive wheels, a drive transmission connecting the induction motor to the drive wheels, a gear box and clutch connected in said drive transmission, a speed control pedal, a brake pedal, bias means controlling the operating frequency of said inverter so that the motor slip speed is that required to produce a desired motor output torque, first signal generating means controlled by said motor and providing said bias means with a first signal significant of the actual speed of the motor, and second signal generating means controlled by said speed control pedal and producing a first range of second signals with slight depression of the speed control pedal and a second range of second signals with further depression of the speed control pedal said second signal generating means providing said second signals to the bias means; said bias means so controlling said inverter output frequency and the gears being so chosen that the motor delivers the called-for torque at high efficiency without overheating and the influence of said first range of second signals on the bias means is to so vary the inverter output that the motor is regeneratively braked by feeding power back through the inverter to the battery while the influence of said second range of second signals on the bias means is to vary the inverter output to accelerate the motor to an increased torque delivery dependent on the pedal position.