Variable speed induction motor with integral ultrasonic PWM inverter

Describes a variable speed motor made by integrating an inverter into the end cowling of a modified induction motor. This evolutionary step makes for economies in filtering and cooling. The inverter strategy is PWM based on a 20 kHz asynchronous carrier, and uses the latest FREDFET power switches. Other unique characteristics are the addition of a third harmonic for greater output voltage and a new technique for smooth reversing.<>