• Title/Summary/Keyword: Inductance saturation

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The Analysis of Torque Ripple of SRM Using Artificial Neural Network (신경회로망을 이용한 SRM의 맥동토오크 해석)

  • 오석규;최태완
    • The Transactions of the Korean Institute of Power Electronics
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    • v.3 no.3
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    • pp.256-262
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    • 1998
  • The torque of SRM depends on phase current and the derivative of inductance. But the inductance of SRM is nonlinearly changed according to rotor position angle and phase current because of saturation in magnetic circuit, and it is difficult to control the desired torque. This paper proposes inductance modeling method using ANN(Artificial Neural Network) that is used to simulate the inductance which is nonlinearly varied with rotor position and current. The torque ripple is analyzed and input voltage and current condition to reduce torque ripple is simulated by inductance model.

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Variable Coefficient Inductance Model-Based Four-Quadrant Sensorless Control of SRM

  • Kuai, Song-Yan;Li, Xue-Feng;Li, Xing-Hong;Ma, Jinyang
    • Journal of Power Electronics
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    • v.14 no.6
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    • pp.1243-1253
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    • 2014
  • The phase inductance of a switch reluctance motor (SRM) is significantly nonlinear. With different saturation conditions, the phase inductance shape is clearly changed. This study focuses on the relationship between coefficient and current in an inductance model with ignored harmonics above the order of 3. A position estimation method based on the variable coefficient inductance model is proposed in this paper. A four-quadrant sensorless control system of the SRM drive is constructed based on the relationship between variable coefficient inductance and rotor position. The proposed algorithms are implemented in an experimental SRM test setup. Experimental results show that the proposed method estimates position accurately in operating two/four-quadrants. The entire system also has good static and dynamic performance.

The Calculation of Transformer Inductance by the Finite Element Method (유한요소법에 의한 변압기 인덕턴스 계산)

  • 배진호;노채균
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.34 no.7
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    • pp.267-275
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    • 1985
  • The finite element method for calculating single phase transformer inductance is presented in this paper. There are three basic definitions of saturated transormer inductance. The set of nonlinear finite element equations is solved by the Newton-Raphson method which assures nearly quadratic convergence of the iteration process. The effect of perturbation of currents of this transformer is used to calculate the saturated winding inductance. This approach is used to calculate the apparent, effective and incremental inductance of single phase transformer. The apparent inductance is in good agreement with resting result. The approach enabled one to study the variation of winding inductance according to the saturation levels in the core at any operating point.

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Study on Calculation of Mutual and Self-inductance in SRM with Full-pitched winding (Full-pitched winding SRM에서의 상호(相互) 및 자기(自己) 인덕턴스의 산정에 관한 연구)

  • Baik, Seung-Kyu;Lee, Chi-Woo;Jung, Tae-Uk;Lee, Il-Chun;Hwang, Young-Moon
    • Proceedings of the KIEE Conference
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    • 1996.07a
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    • pp.31-33
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    • 1996
  • A SRM develops its torque according to the inductance variation as the rotor position and the phase current. The variation of the inductance and the phase current plays an important role in output characteristics. Predicting and calculating the inductance is invaluable in the study of SRM. This paper suggests the estimation method of inductance as variation of phase current and rotor position considering magnetic saturation of motor core. This method is also applied to full-pitched winding SRM.

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Torque Characteristics by the Inductance Profiles of a Switched Reluctance Motor (Switched Reluctance Motor에서 인덕턴스 프로필에 따른 토오크 특성)

  • Kong, Gwan-Sik;Park, Han-Woong;Ahn, Jin-Woo;Hwang, Young-Moon
    • Proceedings of the KIEE Conference
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    • 1992.07b
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    • pp.597-599
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    • 1992
  • A calculation method for predicting the instantaneous torques by the inductance profiles of a switched reluctance motor (SRM) is presented. The method considers saturation and nonlinearities in the magnetic circuits. The inductance of SRM varies complex according to the input current waveforms and rotor position angle, thus the accurate calculation technique is needed to estimate the inductance value at arbitary input current and rotor position angle. This paper describes how the inductance profiles influence the torque produced by the input current of SRM and, proposes a calculation technique of the permeabilities, reluctances, current waveforms and torques of a 6/4 3-phase SRM.

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A Novel Method for the Identification of the Rotor Resistance and Mutual Inductance of Induction Motors Based on MRAC and RLS Estimation

  • Jo, Gwon-Jae;Choi, Jong-Woo
    • Journal of Power Electronics
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    • v.18 no.2
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    • pp.492-501
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    • 2018
  • In the rotor-flux oriented control used in induction motors, the electrical parameters of the motors should be identified. Among these parameters, the mutual inductance and rotor resistance should be accurately tuned for better operations. However, they are more difficult to identify than the stator resistance and stator transient inductance. The rotor resistance and mutual inductance can change in operations due to flux saturation and heat generation. When detuning of these parameters occurs, the performance of the control is degenerated. In this paper, a novel method for the concurrent identification of the two parameters is proposed based on recursive least square estimation and model reference adaptive control.

Analysis of Inductance Variation Characteristics in Interior Permanent Magnet Synchronous Motor (매입형 영구자석 동기 전동기의 인덕턴스 리플 특성 분석)

  • Lee, Sang-Yub;Kwak, Sang-Yeop;Jung, Hyun-Kyo
    • Proceedings of the KIEE Conference
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    • 2006.07b
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    • pp.821-822
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    • 2006
  • In the case of the interior permanent magnet synchronous motor (IPMSM), it is important to know the accurate machine parameters in the design step. In particular, d- and q- axis inductance are expected to have ripple characteristics, due to the mechanical structure and the degree of magnetic saturation. In this paper, this feature is expressed as inductance variation. Inductance variation of the IPMSM is calculated with finite element analysis, and the reason for inductance variation is identified. Finally the validity of this paper is verified by the comparison with the experimental results.

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An Algorithm for Detecting CT Saturation (변류기 2차전류의 포화 여부 판단 알고리즘)

  • Gang, Yong-Cheol;Ok, Seung-Hun;Gang, Sang-Hui
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.50 no.6
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    • pp.275-278
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    • 2001
  • This paper presents an algorithm for detecting current transformer (CT) saturation. At the instants of beginning (or end) of saturation, as a magnetizing inductance of the core is changed significantly, the shapes of the secondary current are also changed significantly though secondary currents are continuous the instants. At the instants, the second-order of third-order difference of the secondary current has big values. Thus, the third difference of the current is used to detect the beginning/end of CT saturation in this paper. If the magnitude of third-order difference of the secondary current is larger than a threshold value, the CT begins of ends saturation at the instants. The proposed detection method is unaffected by the amount of residual flux. The results of various tests with residual flux from -80% to +80% indicate satisfactory performance of the method.

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Analytical Study Considering Both Core Loss Resistance and Magnetic Cross Saturation of Interior Permanent Magnet Synchronous Motors

  • Kim, Young-Kyoun
    • Journal of Magnetics
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    • v.17 no.4
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    • pp.280-284
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    • 2012
  • This paper presents a method for evaluating interior permanent magnet synchronous motor (IPMSM) performance over the entire operation region. Using a d-q axis equivalent circuit model consisting of motor parameters such as the permanent magnetic flux, copper resistance, core loss resistance, and d-q axis inductance, a conventional mathematical model of an IPMSM has been developed. It is well understood that in IPMSMs, magnetic operating conditions cause cross saturation and that the iron loss resistance - upon which core losses depend - changes according to the motor speed; for the sake of convenience, however, d-q axis machine models usually neglect the influence of magnetic cross saturation and assume that the iron loss resistance is constant. This paper proposes an analysis method based on considering a magnetic cross saturation and estimating a core loss resistance that changes with the operating conditions and speed. The proposed method is then verified by means of a comparison between the computed and the experimental results.

Active Cancellation of PMSM Torque Ripple Caused by Magnetic Saturation for EPS Applications

  • Lee, Geun-Ho
    • Journal of Power Electronics
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    • v.10 no.2
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    • pp.176-180
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    • 2010
  • This paper deals with a control method to reduce the torque ripple of a permanent magnet synchronous motor (PMSM) for electric power steering (EPS) systems. Such an application requires a very low torque ripple in order to maintain a good steering feel. However, because of spatial limitations, it cannot help having a partial saturation in the iron core of the PMSM for an EPS system, and this saturation results in a significant torque ripple. Thus, this paper analyzes the torque ripple caused by the magnetic saturation of a PMSM and proposes a method with respect to inductance measurement to verify the partial saturation. In addition, it is shown that a compensation current is needed in order to minimize the torque ripple when a PMSM is driven in the high torque region. The estimation process of the current and the torque ripple decreased by the current are presented and verified with test results.