Automatic Tuning for Sensorless Commissioning of Synchronous Reluctance Machines Augmented With High-Frequency Voltage Injection.

Sensorless control of synchronous reluctance motors (SyRMs) relies on the knowledge of the machine current-to-flux maps. Previous work demonstrated the feasibility of sensorless identification of the flux maps, performed by exciting the machine with square-wave voltage pulses at standstill, and without the need of rotor locking. The rotor position was initially estimated and then used throughout the identification, in open-loop fashion. In some cases, rotor oscillation and eventually position drift led to stop the identification before the programmed $dq$ current domain was covered entirely. In this paper, the rotor position is closed-loop tracked during the motor commissioning to counteract the occurrence of rotor movement. The hysteresis-controlled excitation voltage is augmented with an high-frequency (HF) square-wave voltage component, and the position is tracked through demodulation of the current response to such HF component. The proposed approach is experimentally verified on a 2.2-kW SyRM prototype. The results show that the $i_d, i_q$ commissioning domain is substantially extended, resulting in more accurate flux maps. Moreover, self-tuning of the method is addressed and possible causes of error are analyzed and commented. [ABSTRACT FROM AUTHOR]