Signal-injection-assisted full-order observer with parameter adaptation for synchronous reluctance motor drives

A back-electromotive-force-based position observer for motion-sensorless synchronous reluctance motor (SyRM) drives is augmented with parameter adaptation laws for improved operation at all speeds, including standstill. The augmented observer is theoretically analyzed under various operating conditions. The analysis indicates that the stator-resistance adaptation should be enabled only at low speeds, the d-axis inductance adaptation should be enabled only at medium and high speeds near no load, and the q-axis inductance adaptation should be enabled only at high speeds under high load. The augmented observer is experimentally evaluated using a 6.7-kW SyRM drive.