Analysis of the impact of pulse-width modulated inverter voltage waveforms on AC induction motors

The purpose of this paper is not to reveal any new technology or major break through pertaining to the impact of pulse width modulated (PWM) adjustable speed drives operating on AC motors. Nor is it to discuss the merits of the various designs of the drives. The applications are also well defined. The area where much confusion still exists deals with the voltage waveform impact on the motor performance. Hence, this is the central theme of the paper. The author has assumed that the traditional fundamental sinewave voltage is (except for starting or outside influences) a steady state condition, with a maximum and an RMS value. The effects of the maximum voltage, rate of rise, switching frequencies, resonance and harmonics are all considered