Frequency control of asynchronous electric drives in transport

The present article deals with the peculiarities of induction motor drives, as well as the methods of increasing their efficiency in static modes. The physical process of reducing the electromagnetic torque by increasing frequency of the supply voltage is illustrated by vector diagrams and proved by mathematical analysis of the refined Kloss formula. Under heavy load the motor flux should be increased by increasing the motor voltage, and if it isn´t possible - by reducing the frequency. The proposed algorithms are confirmed by experiments on traction drive of self-propelled car.