A Method for Estimating Initial Pole Position of Surface Permanent Magnet Synchronous Motors Using Pulse Voltage

摘要

The initial pole position must be estimated for speed sensorless vector control of PM motors. This paper presents a method to estimate initial pole position for Surface Permanent Magnet Synchronous Motors (SPMSM). For estimating the initial pole position, we utilize Fourier transformation for detecting the inductance change caused by rotor magnetic saliency. The six inductances, obtained by Fourier transformation of the voltage and current measured when a pulse voltage is applied to the motor armature winding respectively, will directly provide the exact information of pole position. The polar distinction is also carried out using Fourier transformation on the basis of the inductance change caused by magnetic saturation, Experimental results on a 0.3-kW 8-pole SPMSM demonstrate the validity of the proposed method. Although no machine was coupled with the tested motor, there was no change in rotor position during pole position estimation. In polar distinction, the maximum rotor position change was only 1.38 electric degrees. A method to estimate initial pole position without a motor voltage sensor is also discussed.