Compensation of rotor positon estimation errors in sensorless dual-three phase PMSM drives through back-EMF sensing

The paper proposes a simple method to enhance rotor position estimation carried out from back-EMF observers on sensorless dual-three phase permanent magnet synchronous motor drives. The influence of magnetic saturation and temperature variation on the estimated rotor flux position are mitigated through a direct back-EMF measurement. This is accomplished by setting to zero for a short time the phase current on one of the three-phase windings, while the other is tasked to generate the whole motor torque. The proposed method does not require any motor parameter knowledge, it does not require any additional high frequency test signal and it can be exploited under standard drive operating conditions. The paper describes the application of the proposed method on surface mounted permanent magnet synchronous motor drives, including simulations and experimental validation.