Design and Implementation of Sensorless SPMSM Drive with Improved Rotor-position Estimator

Abstract

The presence of the external position sensors increases the size of the motor and the cost of the drive and may reduce the reliability of the system To drive a motor without a transducer many sensorless control strategies have been investigated over the last several decades Among these strategies open-loop voltage-model-based method is the simplest way to fulfill the sensorless control However the use of an integrator in the control loop causes the initial value and the dc drift problems To eliminate these problems a more complicated algorithm would be needed In this thesis a new rotor-position estimating strategy is proposed for surface-mounted permanent-magnet synchronous motor (SPMSM) drive systems The initial value and the dc drift problems can be solved in the proposed rotor-position estimator by computing the phase angle of the flux-linkage vector through estimating the back-electromotive-force (EMF) angle with an adder or subtractor instead of integrating the back-EMF with an integrator Compared with the existing approaches the proposed algorithm thus has faster system dynamic response To implement the sensorless-drive system the initial-position locating scheme the motor startup method and the design of the proposed rotor-position estimator are presented in the thesis The feasibility of the proposed method is then verified by the simulation and the experimental results of a 1 kW sensorless-drive system Both the results justify that the proposed method can improve the complexity of the existing algorithm and avoid the problems in the use of an integrator

Date of Award	2014 Nov 24
Original language	English
Supervisor	Hong-Tzer Yang (Supervisor)