Speed Control Method for PM Motor using Speed Observer and Low Resolution Encoder

Abstract

This paper proposes a new speed control method for PM motor using a low resolution encoder and a speed observer. The servo system should be economical and simple. For this purpose, this paper realizes the high performance speed control system using a low resolution encoder, whose performance is nearly equal to the performance of speed servo system using a conventional optical encoder. The speed observer uses the information of motor current and motor voltage. The rotor position is calculated by the estimated value of speed observer. This observer has the influence of electrical parameter variation. This paper proposes the correction algorithm of both the voltage error of PWM Inverter and the electrical parameter variation. The experimental results and numerical simulation results point out that the proposed speed control system has the desired speed response, on condition of parameter variations and load torque perturbation.