Position sensorless control of the Reluctance Synchronous Machine considering High Frequency inductances

Position sensorless control of the reluctance synchronous machine (RSM) at zero and low speed is possible using high frequency (HF) carrier injection. The standard d-q model of the RSM reveals greatly varying machine parameters for different working points of fundamental current: this fact needs to be taken into account in the design of the fundamental current controller to ensure stability. Similarly, the HF machine parameters vary greatly and should be considered in the demodulation scheme for the estimated rotor position. This paper shows that the effective HF inductances are different to the standard fundamental model inductances, how they are influenced by saturation and how this knowledge can be used to ensure stable and reliable sensorless control.