• Title, Summary, Keyword: torque ripples

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Design of Cogging Torque and Torque Ripples Reduction for High Precision Controlled SPMSM (정밀제어용 표면부착형 영구자석 동기전동기의 코깅토크 및 토크리플 저감 설계)

  • Kim, Chang-Ki;Lee, Sang-Gon;Jung, Sang-Yong
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.10
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    • pp.1923-1929
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    • 2009
  • The design of SPMSM(surface mounted permanent magnet synchronous motor) has been performed to reduce cogging torque and torque ripples. In general, cogging torque and torque ripples are affected by the shapes of teeth width, yoke depth, magnet pole arc, etc. Particularly, the minimum design point of cogging torque and torque ripples are different so that the design of SPMSM should be done to compromise both of them for precision application. In this paper, the design of PMSM for EPS(electric power steering) system is performed to verify the validity, and the design characteristics versus teeth width, yoke depth, and magnet pole arc are investigated in order to find out the minimum point of cogging torque and torque ripples. In addition, skew of PM is applied for cogging torque reduction.

Torque Ripple Reduction Algorithm of PM Synchronous Motor at High Speed Operation (영구자석 동기 전동기의 고속운전 시 토크리플 저감 알고리즘)

  • Kim, Jong-Hyun;Cho, Kwan-Yuhl;Kim, Hag-Wone
    • The Transactions of the Korean Institute of Power Electronics
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    • v.20 no.5
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    • pp.429-436
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    • 2015
  • Torque ripples generate mechanical vibration at low speed and acoustic noise at high speed. The back emf harmonics of a PM synchronous motor is one of the main sources of torque ripples. To reduce torque ripples resulting from back emf harmonics, dq-axis harmonic currents that reduce the torque ripples are generally compensated to the current controller. Harmonic current compensation is effective at low speed, but it is not applicable at high speed because of the limited bandwidth of the current controller. In this study, dq-axis harmonic voltage compensation that can reduce torque ripples at high speed is proposed. The dq-axis harmonic voltages are calculated from the motor speed and the dq-axis harmonic currents. The effectiveness of the proposed method in reducing torque ripple is verified by a simulation and experiments.

Current Variation Method for Reducing Torque Ripples of Linear Motor (선형 전동기의 상전류 조정을 통한 토크리플 저감법)

  • Kim, Min-Jae;Lim, Jae-Won;Jung, Hyun-Kyo
    • Proceedings of the KIEE Conference
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    • pp.85-87
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    • 2009
  • Linear motor is an energy conversion device which makes kinetic energy from electrical energy. This paper presents a method to reduce torque ripples by variation of the current. The torque ripples are basically caused by detent force so this method has a focus on reducing detent force. The torque ripples were calculated by finite element method.

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Automatic Velocity Ripple Compensation Algorithm by Feedforward Control (피드포워드를 이용한 속도리플 자동 보상 알고리즘)

  • Han, Ji Hee;Kim, Jung Han
    • Journal of the Korean Society for Precision Engineering
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    • v.30 no.9
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    • pp.951-959
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    • 2013
  • In order to improve the speed performance of the direct drive mechanical systems, a comprehensive analysis of the velocity ripples of blushless DC motors should be required. Every motor has a certain level of torque ripples when it generates power, and the generated torque ripple also makes the velocity ripples in the final output stage in speed control system. In this paper, a novel algorithm for reducing velocity ripples is proposed based on the modeling of torque ripples for BLDC motors. Various algorithms have been made for torque ripples, but usually they should be installed inside the amplifier logic, result in the difficulties of flexibility for various kinds of torque ripples. The proposed algorithm was developed for being ported in the controller not the amplifier, and it has the capability of the automatic compensation adjustment. The performance of the proposed algorithm was verified by effective simulations and experiments.

Torque Ripples Minimization of DTC IPMSM Drive for the EV Propulsion System using a Neural Network

  • Singh, Bhim;Jain, Pradeep;Mittal, A.P.;Gupta, J.R.P.
    • Journal of Power Electronics
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    • v.8 no.1
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    • pp.23-34
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    • 2008
  • This paper deals with a Direct Torque Control (DTC) of an Interior Permanent Magnet Synchronous Motor (IPMSM) for the Electric Vehicle (EV) propulsion system using a Neural Network (NN). The Conventional DTC with optimized switching lookup table and three level torque controller generates relatively large torque ripples in an electric vehicle motor drive. For reducing the torque ripples, a three level torque controller is hereby replaced by the five level torque controller. Furthermore, the switching lookup table of the five level torque controller based DTC is replaced with a Neural Network. These DTC schemes of an IPMSM drive are simulated using MATLAB/SIMULINK. The simulated results are compared with the conventional DTC and it is found that the ripples in the torque, as well as in the stator current, are reduced drastically.

An Efficient Method to Determine the Phase Current Commands of SR Motors for Minimum Torque Ripples (SR 모터의 토크리플을 최소화하는 상전류명령 결정 방법)

  • Kim, Chang-Hwan
    • Journal of the Institute of Electronics Engineers of Korea SC
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    • v.49 no.4
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    • pp.78-89
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    • 2012
  • The generated torque of a switched reluctance(SR) motor is highly nonlinear, which makes it difficult to determine the reference current commands for minimum torque ripples. In this paper, we present a computationally simple and efficient method to minimize torque ripples of SR motors based on iterative learning control. The reference current command of each phase minimizing torque ripples is identified in 2-dimensional look-up table form. Our learning control algorithm does not require the torque model, so our method is not affected by model errors and hence is very accurate. In order to justify our work, we present some computer simulation results.

Characteristics Analysis of the Hydraulic Motor Design Variables (유압모터의 설계변수에 대한 특성 검토)

  • Liu, Liang-Liang;Jang, Joosup
    • Transactions of the Korean Society of Automotive Engineers
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    • v.21 no.4
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    • pp.188-194
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    • 2013
  • Hydrostatic pumps and motors occupy an important position in hydraulic system. There are a lot of researches on characteristics of hydraulic pumps, but not hydraulic motors. So in order to know the characteristics of hydraulic motors we had this research. The purpose of this study is to derive and analyze the theoretical calculation of hydraulic axial piston motor torque and torque ripples. Then, analyzed the differences between torque ripples with dead place and without dead place on the valve plate, and modeling a hydraulic motor with AMESim software. Finally, theoretical calculation of hydraulic motor torque ripples was verified from the viewpoint of simulation.

Design Characteristics of PM Motor for Electric Power Steering Aimed at Cogging Torque and Torque Ripples Reduction (코깅토크 및 토크리플 저감을 위한 EPS용 영구자석 전동기 설계 특성)

  • Lee, Sang-Gon;Kim, Chang-Ki;Kim, Sang-Hoon;Jeong, Yu-Seok;Jung, Sang-Yong
    • Proceedings of the KIEE Conference
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    • pp.613_614
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    • 2009
  • Electric power steering(EPS) has many attentions such as fuel consumption improvement, thus it has been widely adopted for automotive application in recent years. In the EPS system, torque vibrations are directly transferred through the steering wheel to the hands of the driver. Hence, the design of PM motors for the EPS should be performed in order to reduce torque ripples including cogging torque. In this paper, Surface mounted Permanent Magnet Synchronous Motor(SPMSM) is designed to reduce torque ripples and cogging torque at a same time for the EPS propulsion and the design results are verified with the experimental ones.

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Design Characteristics of Torque Harmonics Reduction of Induction Motors for Electric Vehicle Propulsion

  • Jeon, Kyung-Won;Kim, Yong-Jae;Jung, Sang-Yong
    • Journal of Magnetics
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    • v.18 no.2
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    • pp.212-215
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    • 2013
  • This paper deals with torque harmonic characteristics and its reduction design of induction motors for electric vehicle (EV) propulsion. For calculating the stator harmonic flux of squirrel-cage induction motor, the numerical methods have been employed on the structural configuration design of stator and rotor teeth. In particular, torque ripples including spatial harmonics are obtained by Finite Element Method (FEM), and their individual harmonic components are identified with Fast Fourier Transform (FFT). In this paper, design modification on the teeth surface gives rise to the significant reduction of torque ripples including spatial torque harmonics, which have been obtained with FEM.

MPTC of Induction Motor Driven with Low Switching Frequency (낮은 스위칭 주파수로 구동되는 유도전동기의 모델예측토크제어)

  • Choi, Yuhyon;Han, Jungho;Song, Joongho
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.29 no.3
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    • pp.61-68
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    • 2015
  • When medium and large induction motors are driven by 2-level inverters with low switching frequency, induction motors provoke deteriorated performances resulted from large torque ripples, flux ripples, and large current distortion. Model predictive torque control(MPTC) for a fast torque control of induction motors is also suffered from large torque ripples when the induction motors are fed by 2-level inverters that are based on 6 active voltage vectors with low switching frequency restricted. To solve this problem, this paper proposes a new MPTC method based on both a 12 active voltage vector and an optimized duty ratio calculation. The proposed control strategy illustrates its effectiveness under the various operating conditions through simulation works.