Analysis of Optimize Designing Small Size BLDC Motor Considering Air Gap Clearance

Abstract

BLDC motor(Brushless DC Motor) is used in various applications like scientific studies, industrial, medical device industry and so on. Recently, medical device needs high torque, high efficiency motor and most of motor used in medical device are BLDC motor. Compared to motor used in other application, motor used in medical device has more restrictions on control simplicity and small sizing. If diameter and stacking length are different from initial size condition, medical device production is impossible. If initial size condition is changed, all internal configuration of medical device changes. For this reason, BLDC motor used in medical device designing has to meet initial condition. To meet small sizing and control simplicity, BLDC motor has structure of SPM type BLDC. In case of SPM type, rotor structure can be designed by Poles and permanent magnet shape. According to magnet size, air gap clearance changes and torque of motor changes. Optimized magnet size is able to be chosen by magnetic equivalent circuit. This paper show optimization of designing small size BLDC motor.