The Research of The Sensorless Drive Technology for The Three-Phase Brushless DC Motor

• Main Authors: Wei-hsun Lai, 賴威勳
• Other Authors: Shir-Kuan Lin
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/22839434599206642922

碩士 === 國立交通大學 === 電機與控制工程系所 === 93 === Sensorless brushless DC motors have been widely used for HDD ,DVD devices because of their high speed, fast response and small size. However, the rotation of motor requires special techniques because there are not any position sensors in the motor. Most techniques use the back EMF to detect motor position. However, the above techniques have a common problem: The amplitude of back EMF is too small at low speed to be detected because the amplitude is proportional to rotation speed. Therefore we need a serise of open-loop sequence to accelerate the motor speed. When the back EMF is large enough, the mode is changed from open-loop mode to close-loop mode and the motor is self-commutated by the back EMF. Thus the important thing during open-loop mode is to acquire the largest amplitude of back EMF as quickly as possible.This paper raises two new open-loop sequences that could acquire larger amplitude of back EMF in the short time. Therefore the time of the start-up of the motor can be shortened. Besides, in order to make research of the sensorless drive techniques of sensorless contorl IC, his paper uses IC:BD6609fv to drive a BLDCM and proposes many method to test this IC. The proposed new open-loop sequences are verified with the Visual C++ simulation firstly and then is realized with FPGA-based chip collocating with voltage sensing circuit, motor drive and peripheral circuit for proving the announced sequences are valid .