Dynamic Model of the Induction Motor

Abstract

The well known equivalent circuit of the induction motor allows calculation of the basic quantities of a given motor, such as stator current, power factor, developed torque, etc., when the motor operates in the steady state, with constant speed and fixed, balanced, sinusoidal supply voltage. The electrical quantities are represented as phasors and the developed torque is calculated as the output power divided by the angular velocity of the rotor. Since the output power is computed as an average (per cycle), and not as an instantaneous, quantity, it follows that it is also an average, not an instantaneous, value of the torque that is determined. The equivalent circuit is, therefore, insufficient for analysis of transient operating conditions. Also, if a non-sinusoidal voltage, typical for power electronic converters, is applied to the stator then, even in the steady state, calculation of the motor performance using the harmonic decomposition and superposition principles is very tedious.

The online version of the original chapter can be found at http://dx.doi.org/10.1007/978-1-4615-2730-5_7