Implementation of a sensorless interior permanent magnet synchronous drive based on current deviations of pulse-width modulation switching

This study proposes a rotor position estimating method by detecting the stator currents under each pulse-width modulation switching state for an interior permanent magnet synchronous motor drive system. The proposed sensorless motor drive system can be applied in an air conditioner without injecting any high-frequency sinusoidal or cosine voltage signal. The operating speed range can be effectively extended because the maximum available voltage is increased when compared to the high-frequency sinusoidal or cosine voltage injection method. The detailed analysis is discussed here. A digital signal processor, TMS-320-F-2812, is used to execute the rotor position estimator and controller. Several experimental results are included to evaluate the theoretical analysis. The experimental results show that the proposed sensorless method can provide satisfactory performance for a closed-loop interior permanent magnet synchronous motor drive system applied in an air conditioner.