Rotor Position Estimation

High-frequency excitation sensorless control methods measure the response of the machine to some form of high-frequency excitation from which the rotor position is estimated. The utilization of these meth ods is feasible in both induction and PMSMs. The design of the machine strongly influences its salient behavior, meaning that not all designs are adequate for their use in sensorless applications. All the methods respond to the same physical principles, with the main differences among them being the type of high frequency signal excitation and the type and number of signals that are measured. Stable operation, with similar values of accuracy, has been reported for PWM-based methods and for carrier-signal injection-based methods.