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

• Main Authors: Jhen-YuLi, 李鎮宇
• Other Authors: Hong-Tzer Yang
• Format: Others
• Language: en_US
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/2t734x

碩士 === 國立成功大學 === 電機工程學系 === 103 === 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.