Position Sensorless Control Method in Low Speed Region for Permanent Magnet Synchronous Motors Using the Neutral Point Voltage of Stator Windings

Abstract

In this paper, we propose a new sensorless control method using the neutral point voltage of stator windings. Each inductance of the three phase coils of the permanent magnet synchronous motor (PMSM) is slightly changed by the rotor magnet flux. As a result, the neutral point voltage also changes depending on the rotor position. According to this principle, the rotor position can be estimated by detecting the neutral point voltage, even in the zero speed region. We implement this technique and show the experimental results.