A rotor position estimation of SR motor based on complex plane expression of phase inductance

This paper describes a new position sensorless control method of 3-phase SRM based on the complex plane expression of phase inductance. The rotor position is simply obtained without magnetic characteristics of the motor and additional hardware. In this method, assuming the phase inductance waveform to be sine wave, the rotor position is obtained by computing the angle of the space vector of inductance. The space vector of inductance is computed from excited phase currents. Experimental results show the validity of the proposed method.

I. Introduction

Switched reluctance motor (SRM) drives are suitable for variable speed industrial applications because of the simple structure and high-speed capability. However, it is necessary to detect the rotor position obtained from a position sensor, such as an encoder, resolver, or Hall sensor in order to control the SRM. These sensors usually are attached to the motor shaft. By using these sensors, the reliability of the drive system is reduced and the additional cost and machine size are increased.