What is the carrier frequency? I found this in the specification of an IPM motor. Thanks.

 

Welcome to AAC.

IPM motor speed control is done by injecting a high frequency carrier to sense impedance changes. This is ”sensorless” control. The motor controller can dynamically adjust parameters to determine the rotor position. The carrier is the high frequency signal that carries the information about the state of the rotor and it is sensed by the controller for positional feedback.

 

I am totally impressed by"Y" being able to know the subject from that question as posted. Somebody with mind reading ability, and at a distance, even.
Reading motor position by impedance change measurement. The frequency selected will depend on the size of the motor is my guess, and definitely fairly high, in the tens of kilohertz is my guess.