• Title/Summary/Keyword: PM BLDC

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Distortion of Magnetic Field and Magnetic Force of a Brushless DC Motor due to Deformed Rubber Magnet (BLDC 모터의 고무 자석 형상 변형으로 인한 자계 변형 및 불평형 자기력 해석)

  • Lee, Chang-Jin;Jang, Gun-Hee
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2007.11a
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    • pp.834-839
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    • 2007
  • This paper investigates the distortion of magnetic field of a brushless DC (BLDC) motor due to deformed rubber magnet. Global or local deformation of rubber magnet in the BLDC motor is mathematically modeled by using the Fourier series. Distorted magnetic field is calculated by using the finite element method, and unbalanced magnetic force are calculated by using the Maxwell stress tensor. The first harmonic deformation in the global deformation of rubber magnet generates the first harmonic driving frequency of the unbalanced magnetic force, and the rest harmonic deformations of rubber magnet except the harmonic deformation with multiple of common divisor of pole and slot introduces the driving frequencies with multiple of slot number ${\pm}1$ to the unbalanced magnetic force. However, the harmonic deformation with multiple of common divisor of pole and slot does not generate unbalanced magnetic force due to the rotational symmetry. When the rubber magnet is locally deformed, the unbalanced magnetic force has the first harmonic driving frequency and the driving frequencies with multiples of slot number ${\pm}1$.

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Characteristics of Torque and Vibration-Noise take into account Permanent Magnet Overhang of BLDC Motor for Robots (로봇 구동용 BLDC Motor의 영구자석 오버행에 따른 토크 및 진동.소음 특성)

  • Kang, Gyu-Hong;Kim, Duck-Hyun
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.55 no.7
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    • pp.346-352
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    • 2006
  • In Brushless DC Motor, there are Permanent Magnets (PMs) with driving circuit and sensor for detecting to rotor position and rotation speed. In the case of using hall IC sensor which response to magnetic flux, that is required to additional sensor magnet for rotor position detecting. Most of BLDC motor, However, take asymmetrical overhang of PM in rotor instead of additional sensor magnet for operating of hall IC sensor. The asymmetrical overhang of PM occur rotor thrust to z-axis direction that is lead to not only damage of bearing but also intensive noise and vibration. Therefore, the analysis of magnet overhang effect in the side of vibration and drive to hall If sensor is required to precise. In this paper, 2-D Finite Element Method is used to solve precise field computation and thrust of z-axis direction considering asymmetrical magnet overhang. And also the z-axis thrust from the analysis result is compared to experimental result. In conclusion, the purpose of this paper minimize to noise and vibration of BLDC Motor as analyzes to asymmetrical magnet overhang effect.

Development of Controller for MPB BLDC Motor (MPB BLDC 전동기의 제어기 개발)

  • 김상욱;김보열
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.50 no.3
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    • pp.117-124
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    • 2001
  • The aim of this paper is to develop a controller of multi-phase bipolar brushless DC (MPB BLDC) motors for an electric bicycle. A MPB BLDC motor has a Permanent magnet rotor in which the magnetic arrangement is radial to the shaft and integral to the rotor laminations. This technique concentrates flux, giving a higher flux density than a surface-mounted PM motor and increases reluctance torque. The stator of MPB BLBC motor has parallel winding, allowing multi-phase separate independent controllability. It gets much more high power than wye-connection at same low voltage. The conventional techniques of exited with modulation(EWM), bidirection control, and partial square wale control are Proposed with one H-bridge and two photo sensors per phase. The Proposed controller is satisfied for the limited speed control and designed for system stability Experimental results show the performance of the proposed controller of MPB BLDC motors for an electric bicycle.

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Design of SPOKE Type BLDC Motor for Traction Application Considering Irreversible Demagnetization of Permanent Magnet

  • Hur Jin;Kang Gyu-Hong
    • KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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    • v.5B no.2
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    • pp.129-136
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    • 2005
  • This paper presents a design strategy of SPOKE type BLDC motors considering an irreversible demagnetization of a permanent magnet (PM). So the irreversible demagnetization characteristic of the motor is analyzed by rotor structure. The instantaneous currents in either starting or lock rotor condition, which are calculated from the current dynamic analysis, are applied to the analysis of the irreversible demagnetization field by FEM. In irreversible demagnetization analysis by FEM, the variation of residual flux density in PM is analyzed using the non-linearity of magnetic core on B-H plan. The analysis results are compared to several rotor structures and used for optimize the rotor structure.

A Study on the Cogging Torque Reduction in a Novel Axial Flux Permanent Magnet BLDC Motor (축방향 자속형 영구자석 BLDC 전동기의 코깅 토크 저감에 관한 연구)

  • Jo, Won-Young;Lee, In-Jae;Koo, Dae-Hyun;Chun, Yon-Do;Cho, Yun-Hyun
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.55 no.9
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    • pp.437-442
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    • 2006
  • Cogging torque, the primary ripple component in the torque generated by permanent magnet (PM) motors, is due to the slotting on the stator or rotor. This article shows the reduction of cogging torque in a novel axial flux permanent magnet (AFPM) motor through the various design schemes. 3D finite element method is used for the exact magnetic field analysis. The effects of slot shapes and skewing of slot on the cogging torque and the average torque have been investigated in detail.

A Design Optimization of Asymmetric Air-gap Structure for Small 3-phase Permanent Magnet SPM BLDC Motor

  • Kam, Seung-Han;Jung, Tae-Uk
    • Journal of Magnetics
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    • v.20 no.1
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    • pp.91-96
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    • 2015
  • As many researchers are relentlessly trying to improve the power generation schemes from the power grid, to meet the constantly increasing electricity demand. In this paper, the results of a finite element analysis are carried out to study on a design optimization of an asymmetric air-gap structure in 3-phase Permanent Magnet Brushless DC Motors. To achieve a high efficiency for a 3-phase PM BLDC motor, the asymmetric air-gap structure is proposed considering the rotation direction of a motor. Generally, a single-phase BLDC motor is applied asymmetric air-gap structure for starting. This is because the asymmetric air-gap structure causes reluctance variation so the motor can utilize reluctance torque toward a rotation direction. In this paper, the asymmetric air-gap is applied to 3-phase BLDC SPM motor so it utilizes reluctance torque with alignment torque. A proposed model is designed by 2-D FE analysis and the results are verified by experimental test.

Sensorless Precision Speed Control of PM BLDC Motor (PM BLDC 모터의 센서리스 정밀 속도 제어)

  • Won, Chung-Yuen;Kim, Yuen-Chung;Yoon, Yong-Ho;Kim, Hack-Seong;Lee, Byuong-Kuk;Chun, Jang-Sung
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.20 no.1
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    • pp.48-56
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    • 2006
  • This paper studies particularly applicable method for sensorless PM BLDC motor drive system. The waveform of the motor internal voltages(or back emf) contains a fundamental and higher order frequency harmonics. Therefore the third harmonic component is extracted from the stator phase voltage. The resulting third harmonic signal keeps a constant phase relationship with the rotor flux for any motor speed and load condition. Also because of low resolution of estimated signal obtained by the proposed sensorless algorithm, to improve the wide range of speed response characteristic more exactly, we propose the rotor position signal synthesizer using PLL circuit based on estimated signals. Some experimental results are provided to demonstrate the validity of the proposed control method.

Precise Speed Control and Sensorless Technique of PM BLDC Motor Using the PLL Algorithm (PM BLDC 모터의 PLL 알고리즘을 사용한 정밀속도제어 및 센서리스 기법)

  • Lee, Seung-Jun;Yoon, Yong-Ho;Kim, Young-Ran;Won, Chung-Yuen;Choi, You-Young
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2005.05a
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    • pp.449-454
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    • 2005
  • Brushless DC Motor(PM BLDCM) is widely used in industrial applications due to its high efficiency and power density. In order to increase reliability and reduce system cost, this paper studies particularly applicable method for sensorless PM BLDCM drive system. The resulting third harmonic signal keeps a constant phase relationship with the rotor flux for any motor speed and load condition, and is practically free of noise that can be introduced by the inverter switching, making this a robust sensing method. As a result, the method described here is not sensitive to filtering delays, allowing the motor to achieve a good performance over a wide speed range. In addition, a simple starting method and a speed estimation approach are also proposed.

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Electrical Characteristics and Electromagnetic Excitation Force Comparison of PM Motor according to the Driving method (영구자석형 전동기의 구동방법에 따른 전기적 특성 및 전자기적 가진원 분석)

  • Lee, Su-Jin;Kim, Do-Jin;Lee, Byeong-Hwa;Hong, Jung-Pyo
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.23 no.2
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    • pp.144-151
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    • 2013
  • This paper presents a result of the mechanical noise and vibration analysis as well as the electrical characteristics analysis of the permanent magnet(PM) motor according to the driving method that is Brushless DC(BLDC) drive and Brushless AC(BLAC) drive. To do that, the characteristics of the PM motor, which have the same output power but different driving method, are investigated. At that time, the characteristics such as torque, torque ripple and flux density, and so on, are obtained by finite element analysis(FEA). Besides, noise and vibration are obtained by spectrum analysis. The magnetic noise is defined as noise generated from vibrations due to electromagnetic excitation force. In this paper, the electromagnetic excitation force is analyzed and design process of noise reduction is proposed. Finally, The validity of the analysis results is verified by test.

Characteristics Comparison of PM Motor according to the Driving method (영구자석형 전동기의 구동방법에 따른 전자기적 특성 및 진동 소음 비교)

  • Hong, Jung-Pyo;Lee, Su-Jin;Kim, Do-Jin;Lee, Byeong-Hwa;Jang, Woo-Kyo
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2012.10a
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    • pp.522-527
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    • 2012
  • This paper presents a result of the mechanical noise and vibration analysis as well as the electrical characteristics analysis of the permanent magnet (PM) motor according to the driving method that is Brushless DC (BLDC) drive and Brushless AC (BLAC) drive. To do that, the characteristics of the PM motor, which have the same output power but different driving method, are investigated. At that time, the characteristics such as torque, torque ripple and flux density, and so on, are obtained by finite element analysis (FEA). Besides, noise and vibration are obtained by spectrum analysis. The magnetic noise is defined as noise generated from vibrations due to electromagnetic excitation force. In this paper, the electromagnetic excitation force is analyzed and design process of noise reduction is proposed. Finally, The validity of the analysis results is verified by test.

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