학술논문
브러시리스 영구자석 전동기의 정현적 공극 자속밀도 분포를 위한 착자 시스템 설계 및 특성 연구 / A Study on Design of Magnetizing System for Sinusoidal Air-Gap Magnetic Flux Density Distribution and Characteristics of Brushless Permanent Magnet Motor
Document Type
Dissertation/ Thesis
Author
Source
Subject
Language
Korean
Abstract
본 논문에서는 영구자석 표면 부착형(Surface mounted Permanent Magnet type, SPM type) 브러시리스 전동기의 정현적 공극 자속밀도 구현을 위한 착자 시스템의 설계 방법을 제안하였다. parallel로 착자 된 영구자석을 BLDC 전동기의 회전자로 사용한 기존모델과 제안된 착자 시스템에 의해 착자 후, 정현적 자속밀도 분포를 갖는 영구자석을 각각 브러시리스 직류전동기(Brushless Direct Current motor, BLDC motor)와 브러시리스 교류전동기(Brushless Alternating Current motor, BLAC motor)의 회전자로 사용한 개선모델의 특성 실험, 해석 및 비교 분석 하였다.브러시리스 영구자석 전동기의 코깅 토크와 토크 리플 저감을 위해 정현적 공극 자속밀도 분포를 갖는 착자 시스템을 설계하였다. 이때, 착자 요크의 철심 형상은 실험계획법(Design of Experiments, DOE)중의 하나인 요인배치법(Factorial design)을 이용하여 설계 시간의 단축은 물론, 정현적 공극 자속밀도를 갖는 착자 요크 철심 형상을 최적 설계 하였다. 착자 해석 방법은 2차원 유한요소법(Two-Dimensional Finite Element Method, 2-D FEM)과 프라이자흐 모델(Preisach model)을 이용하여 해석하였다. 또한, 시작품 제작과 실험 및 해석을 통하여 정현적 공극 자속밀도 분포를 위한 착자 시스템 설계의 유용성과 시뮬레이션 통해 얻은 해석 치와 실험치의 비교 분석을 통해 해석 방법의 타당성을 입증하였다.
This paper presents a design method of magnetizing system for sinusoidal air-gap magnetic flux density distribution and characteristic analysis of brushless permanent magnet motor.Compared with the other electric motors without a PM, brushless motors with a PM have inherent cogging torque. Cogging torque is produced by the interaction of a rotor magnetic flux and angular variation in the stator magnetic reluctance. It is often a principal source of torque ripple and difficult control problems in brushless PM motors.Several researchers have studied design techniques to reduce cogging torque and torque ripple in brushless PM motors. One of them used a arc-shaping PM which was manufactured to make a sinusoidal air gap MFD distribution. However, it increases manufacturing cost and effort. There were research activities on a conventional winding arrangement method of the magnetizing fixture for a sinusoidal air-gap MFD distribution from an isotropic PM of ring type to reduce cogging torque. However, this method is difficult to obtain free space for winding arrangement with increasing pole numbers and/or with needs of the precise sinusoidal air gap MFD. The magnetizing system which makes a sinusoidal MFD from a magnetized PM by adjusting the pole shape was designed for a design of magnetic sensor. However, through trial and error method, it has been found that it has some disadvantages of having a long design time and difficulties of making a precise sinusoidal MFD.In this paper, a design method of the magnetizing system for a sinusoidal air-gap MFD distribution from an isotropic PM of ring type to reduce cogging torque and torque ripple of the brushless PM motor was proposed. For an optimum design of the magnetizing fixture, a factorial design which is one of the design of experiments (DOE) is used. The magnetization is analyzed by using Preisach model combined with two-dimensional finite element method (2-D FEM). Also, the usefulness of the newly proposed design method is confirmed by the experiment results of cogging torque and the simulation results of torque ripple.
This paper presents a design method of magnetizing system for sinusoidal air-gap magnetic flux density distribution and characteristic analysis of brushless permanent magnet motor.Compared with the other electric motors without a PM, brushless motors with a PM have inherent cogging torque. Cogging torque is produced by the interaction of a rotor magnetic flux and angular variation in the stator magnetic reluctance. It is often a principal source of torque ripple and difficult control problems in brushless PM motors.Several researchers have studied design techniques to reduce cogging torque and torque ripple in brushless PM motors. One of them used a arc-shaping PM which was manufactured to make a sinusoidal air gap MFD distribution. However, it increases manufacturing cost and effort. There were research activities on a conventional winding arrangement method of the magnetizing fixture for a sinusoidal air-gap MFD distribution from an isotropic PM of ring type to reduce cogging torque. However, this method is difficult to obtain free space for winding arrangement with increasing pole numbers and/or with needs of the precise sinusoidal air gap MFD. The magnetizing system which makes a sinusoidal MFD from a magnetized PM by adjusting the pole shape was designed for a design of magnetic sensor. However, through trial and error method, it has been found that it has some disadvantages of having a long design time and difficulties of making a precise sinusoidal MFD.In this paper, a design method of the magnetizing system for a sinusoidal air-gap MFD distribution from an isotropic PM of ring type to reduce cogging torque and torque ripple of the brushless PM motor was proposed. For an optimum design of the magnetizing fixture, a factorial design which is one of the design of experiments (DOE) is used. The magnetization is analyzed by using Preisach model combined with two-dimensional finite element method (2-D FEM). Also, the usefulness of the newly proposed design method is confirmed by the experiment results of cogging torque and the simulation results of torque ripple.