Position sensorless speed control of permanent magnet brushless DC motor

Abstract

Permanent magnet brushless DC (PMBLDC) motors are the latest choice of researchers due to their high efficiency, silent operation, compact size, high reliability and low maintenance requirements. The objective of the present work is to control the speed of the PMBLDC motor without position sensor (Sensorless Control). There are two types of sensorless speed control techniques available in literature. The first type is position sensing using back EMF of the motor and the second one is position estimation using motor parameters. In the second type, rotor position is estimated from the stator voltage and stator current signals. Accordingly, the main contributions of this work are Digital Simulation of PMBLDC Motor Drive with Power Factor Correction by identifying suitable filter for three phase inverter; Speed control by varying the input voltage of the Inverter in the presence of sensor; Speed control by varying the input voltage of the Inverter by sensorless method; Speed control by varying the commutation using gate control method; Speed control by varying the commutation using Space Vector Modulation; Comparing the performance of various controllers and hence identify the most suitable method of speed control;Real time implementation of sensor and sensorless speed control for PMBLDC motor, using PI and FLC scheme. The chapter1 deals with introduction and literature survey. The second chapter deals with voltage control method to control the speed of the PMBLDC motor using PI controller and Fuzzy logic controller (FLC) with Hall sensor. In the third chapter a suitable filter is identified for a three phase inverter to obtain the inverter output with less Total Harmonic Distortion (THD) and improved Power factor. From the quantitative analysis, the rms line current is increased by three times in SVM technique. From the FFT analysis it is observed that SVM generates less THD (0.2897) in the output voltage. newline