Implementation of Sensorless Control by Differentiation Method for Brushless DC Motor Driver

• Main Authors: Yu-Cheng Chou, 周煜晟
• Other Authors: Ming-Ji Yang
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/68u8cx

碩士 === 國立臺北科技大學 === 車輛工程系所 === 103 === This thesis proposed a novel sensorless control for in-wheel brushless DC motor (BLDCM), widely used on electric scooter or pedelec. The proposed method is based on back electromotive force (back-EMF) of BLDCM. Firstly, the motor driver could differentiate the trapezoidal back-EMF by a OPA-type differentiator to obtain the timing of upper and lower base of three phase back-EMF. Besides, these timing are also the six sections of six-step square wave motor drive, and the driving condition of sensorless control. According to the differential results, the differential back-EMF could be separated into zero, positive, and negative, and these signals could be turned into the commutation signal on the basis of the computation of the Microcontroller Unit (MCU). Hence, turning on/off the corresponding MOSFETs of six sections will reach sensorless driving motor. Finally, this thesis verifies the feasibility of proposed method of sensorless control by a BLDCM with 48V/500W and the platform of dynamometer.