Speed sensorless control at low speed for bearingless synchronous reluctance motor based on improved Luenberger observer

For bearingless synchronous reluctance motors (BSRMs), an improved Luenberger observer based on current derivatives is proposed for speed estimation in sensorless control at low speeds. This paper first derives the mathematical model of BSRMs, extracts the current components of the motor torque winding, and performs differentiation. The relationship between the rotor angle and the current derivatives is then derived. The calculated rotor angle is subsequently incorporated into the improved Luenberger observer to estimate the rotor information of BSRMs. Based on this, a sensorless control strategy for BSRMs is established. Finally, the accuracy and reliability of this method are validated through MATLAB/Simulink simulations and experimental platform testing.