• Title, Summary, Keyword: torque harmonics

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Torque Ripple Reduction of an Interior PM Synchronous Motor by Compensating Harmonic Currents Based on Flux Linkage Harmonics

  • Nam, Myung Joon;Kim, Jong Hyun;Cho, Kwan-Yuhl;Kim, Hag-Wone;Cho, Younghoon
    • Journal of Power Electronics
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    • v.17 no.5
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    • pp.1223-1230
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    • 2017
  • The back emf harmonics of a permanent magnet (PM) synchronous motor is a major source of torque ripple. For torque control applications including column fitted MDPS (motor driven power steering) systems, it is essential to reduce the mechanical vibrations due to torque ripples at low speeds. In this paper, a torque ripple reduction algorithm for interior PM synchronous motors is proposed. The harmonic currents that cancel the $6^{th}$ order torque harmonic are added to the nominal dq currents for MTPA (maximum torque per ampere) operation. The compensated harmonic currents are derived from flux linkage harmonics based on a FFT analysis of the back emf harmonics. Simulation and experimental results verify that the $6^{th}$ order torque harmonic and THD of the torque ripple are reduced by compensating the dq harmonic currents.

A Study on the Thoretical Analysis of the Torque Harmonics for Diesel Engines (디젤기관의 토크 하모닉스에 대한 이론적 해석)

  • 이용진;장민오;김의간;전효중
    • Journal of KSNVE
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    • v.10 no.3
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    • pp.465-473
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    • 2000
  • In this crankshaft of marine diesel engines the exciting torques are produced by gas pressure and reciprocating masses. These torques are periodically changing and are extremely out of balance. To calculate the torsional vibrations of propulsion shafting caused by unbalanced torque the torque harmonics are utilized. Until now to calculate the torsional vibrations of propulsion shafting. the torque harmonics have been supplied by the engine maker. When the torque harmonics of an engine are not available the torque harmonics of a similar engine type had to be used. However such data is not suitable for the reliable calculations of torsional vibrations. In this paper the combustion characteristics of marine diesel engines including $\rho{-}\upsilon$ diagram are investigated and the torque harmonics based on these are theoretically calculated. reliability of the calculations is confirmed by comparing them with those of an engine maker. This study should prove useful for the calculations of torsional vibrations for diesel engine propulsion shafting. particularly for 4-stroke engines whose torque harmonics are difficult to obtain directly from the engine and not ordinarily supplied by the engine maker.

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Influence of Torque Ripple Caused by Current Harmonics on Induction Motor Fed PWM Inverter (PWM 인버터로 구동되는 유도전동기 시스템에서 고조파가 토오크 맥동에 미치는 영향에 관한 연구)

  • Baek, S.H.;Kim, Y.;Ham, J.G.;Maeng, I.J.;Sohn, J.M.
    • Proceedings of the KIEE Conference
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    • pp.12-14
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    • 1995
  • It is necessary to analyze exactly the torque ripple components in the harmonics as to decrease the torque ripple. Lower harmonics influence mainly on torque ripple. Among the harmonics, the pairs of 5's, 7's and 11's, 13's are dominant, and the magnitude of each pairs of current harmonics are very significant. Therefore, for decreasing the torque ripple, current harmonic pairs of 6n ${\pm}$1's orders must be simultaneously eliminated. In the case of eliminating one of current harmonic pairs, even though the magnitude of the current harmonics is small, It has great effect on torque ripple.

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Torque Ripple Reduction based on Flux Linkage Harmonics Observer for an Interior PM Synchronous Motor including Back EMF Harmonics (왜곡된 역기전력을 갖는 매입형 영구자석 동기전동기의 쇄교자속 고조파 관측기를 이용한 토크리플 저감)

  • Jin, Yong-Sin;Kim, Hag-Wone;Cho, Kwan-Yuhl;Lim, Byung-Kuk
    • The Transactions of the Korean Institute of Power Electronics
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    • v.18 no.4
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    • pp.367-375
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    • 2013
  • The mechanical vibration of a PM synchronous motor at low speeds due to the back emf harmonics may be serious problems in some application such as MDPS(Motor driven power steering), electric vehicles. In this paper, torque ripple reduction for an interior PM synchronous motor including back emf harmonics is proposed. The dq flux linkage harmonics of the permanent magnet are estimated on real time by using the dq currents of the real system and the model of the MRAS observer. Based on the estimated flux linkage harmonics, the dq harmonic currents for reducing the torque ripples are compensated on the dq reference currents. The estimation of the flux linkage harmonics by the MRAS observer and the torque ripple reduction of the proposed algorithm was verified by the simulation and experiment.

Analysis of Torque Characteristics for the Single-phase Induction Motor Considering Space Harmonics

  • Kim Byung-Taek;Lee Sung-Ho;Kwon Byung-Il
    • Journal of Electrical Engineering and Technology
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    • v.1 no.3
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    • pp.327-331
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    • 2006
  • This paper presents the analysis method for the torque characteristic of the 1-phase induction motor considering space harmonics in the air gap. The equivalent circuit method is used, where the circuit constants are obtained by classic theory. In addition, the space harmonic components in air gap magneto motive force are analyzed and added to the equivalent circuit to obtain accurate torque characteristics in low speed regions. Each torque component due to the harmonics is calculated and the total torque characteristic is obtained and compared with the measurement result.

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.

Influence of Cogging Torque Reduction Method on Torque Ripple in a Surface-Mounted Permanent Magnet Synchronous Motor

  • Kim, Tae-Woo;Chang, Jung-Hwan
    • Journal of Magnetics
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    • v.17 no.2
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    • pp.109-114
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    • 2012
  • The torque characteristics of a surface-mounted permanent magnet synchronous motor (SPMSM) are analyzed in this study. The harmonics of the back electromotive force (EMF) and cogging torque are analyzed by the finite element method to study their effects on the torque ripple. Although low cogging torque can be achieved by varying geometric parameters such as the permanent magnet (PM) offset and notch depth on the stator teeth, the torque ripple is increased in some cases. The analysis results show that the ripple of the generated torque is determined by not only the amplitudes but also the phases of harmonics for the back EMF and cogging torque.

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.

Space vector control considering flux harmonics for PMSM (영구자석형 동기전동기를 위한 고조파 자속을 고려한 공간전압벡터 제어)

  • 박익동;이제희;허욱열
    • 제어로봇시스템학회:학술대회논문집
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    • pp.508-511
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    • 1997
  • Recently the development of motor speed control systems with both good dynamic performance and simple implementation has been required. The vector control scheme considering flux harmonics for the permanent-magnet AC servo motor having low inertia, low weight, and high efficiency is proposed. To reduce the torque harmonics, current harmonics is employed. The vector control strategy is verified through digital simulation.

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Effect of IPMSM d-q Axis Parameters According to Magnetic Saturation and Armature Reaction

  • Jang, Kibong
    • Journal of Electrical Engineering and Technology
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    • v.10 no.2
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    • pp.539-544
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    • 2015
  • FEA was used to analyze inductance and torque of IPMSM. Torque and inductance are analyzed on the dq-axis. It was shown that Ld and Lq have harmonic components, and magnitude as well as phase of the harmonics varies according to the current values. This paper shows the relationship between these inductance harmonics and the 6th harmonic component of torque.