Application considerations for PWM inverter-fed low-voltage induction motors

Pulse-width modulation (PWM) inverters should be applied with special consideration for low-voltage induction motor operation. The power supplied to the motor by a PWM inverter has some adverse effects, which are described. These effects include increased heating, high peak voltages, and increased audible noise. The impact these effects have on a given application is presented. Specific areas discussed include: motor noise caused by different power transistor types and switching strategies; additional motor heating produced by PWM invertor power and the operating speed-torque range; the effects of PWM inverter-produced harmonics on the low-voltage induction motor; PWM inverter designs and their effect on motor insulation systems; and voltage transients generated by semiconductor switching technologies employed in PWM inverters