Microcontrollers in variable frequency inverters

Abstract

In some appliances it is desirable to control the speed of the induction motor. Because of the physics of the of the induction motor the preferred method of controlling its speed is to vary the frequency of the AC voltage driving the motor. The motor will rotate at a speed that is some multiple of the driving frequency based on the number of poles in the motor. This is an open loop type of control and the motor’s load will have an effect on the final steady state speed. Historically, this approach has been expensive and this has limited its application in the consumer market.