Sensorless Control of Interior Permanent Magnet Synchronous Machines Based on the Combination of the Modified FPE Method and SMO

This paper presents a sensorless control method for an IPMSM, which are based on the combination of the modified Fundamental Excitation PWM (FPE) method and the Sliding Mode Observer (SMO). At low speeds the current derivatives at the first active-voltage vector are measured to estimate rotor speed, position and machine inductances, while at medium and high speeds the SMO is employed for sensorless control. The estimated L_d and L_q at low speeds are stored in a look up table and utilized for enhancing the performance of the SMO. The experimental studies have been conducted to verify the improvement of the estimation accuracy and the reduction of the current distortion over a full speed range from zero to rated speed of the proposed hybrid sensorless control method.

I. Introduction

Sensorless control of permanent magnet synchronous motors (PMSM) have been developed significantly due to the advantages of cost, robustness and reliability. In sensorless control, the shaft position and speed sensor are eliminated. The rotor speed and position are estimated by utilizing the fundamental excitation model or the magnetic saliency of the PMSM.