A Driving Torque Prediction of Brushless DC Motor by Using the Measured Current Data

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Journal of the Korea Institute of Military Science and Technology 1999;2(2):242-250.

전류측정 데이터를 이용한 브러쉬 없는 직류전동기의 구동토크 예측

변영철, 전혁수

국방과학연구소

Abstract

This paper presents an estimation scheme of the external torque applied on the motor by using measured motor input current when the IPM(Interior Permanent Magnet) rotor type BLDC motor operates with constant speed. In general, the BLDC motor is controlled by vector control method. If it could be operated at over critical speed, the control scheme must be modified to flux-weakening control method. The external torque applied on the motor using flux-weakening control method could not be calculated by conventional torque equation because the demagnetizing current Id exists in the motor input current. In this paper, the commonly used flux-weakening control method is studied and the modified torque estimation scheme is suggested. The estimation scheme has been verified by the simulations and experimental results.

Key Words: BLDC Motor, IPM Motor, Flux-weakening Control