• Title/Summary/Keyword: Winding error

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Primary Resistance Compensation of Linear Induction Motor Using Thermocouple (Thermocouple을 이용한 선형 유도전동기의 1차측 저항 보상)

  • Kim, Kyung-Min;Park, Seung-Chan
    • Proceedings of the KSR Conference
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    • 2006.11b
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    • pp.742-747
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    • 2006
  • This paper describes online stator-resistance estimation of a linear induction motor(LIM) with cage-type secondary using direct thrust control(DTC), where the resistance value is derived from stator-winding temperature estimation using thermocouple. In this paper, corrected stator resistance has an error in actuality measurement resistance. So compensation coefficient $\kappa$ which is decided through comparison and verifying several times relation of calculated resistance and measured motor line-line resistance. The stator-winding temperature information can also be used for monitoring, protection, and fault-tolerant control of the machine. Also, this paper reports the LIM's responses of the flux measured by the proposed stator resistance compensation algorithm.

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Shield Effects of the Actively Shielded Superconduction Magent for MRI (MRI용 초전도 마그네트의 능동차폐 효과)

  • 배준환;진홍범;고락길;권영길;이언용;손명환;백승규;김해종;류강식
    • Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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    • 1999.02a
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    • pp.113-116
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    • 1999
  • The shield effects of the actively shielded superconducting magnet systems for MRI were investigated. The magnetic field was calculated by FEM considering the winding error and the homogeneity of the magnetic field at the 30cm DSV was presented. The 5 gauss stray field line was restricted within 5m form the magnet center.

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Steady-State and Stability Analysis of Multioutput DC-DC Converter (DC - DC 콘버어터의 다출력화에 따른 정상특성 및 안정성 해석)

  • 김능수;이윤종;김희준
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.37 no.8
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    • pp.534-539
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    • 1988
  • The dynamic chatacteristics and stability including steady state characteristic of the currentfed DC-to-DC converter with multiouput, which has a considerable advantage about the multioutut circuit,are analyzed in this paper. It is performed by using the steady state averaging method. As result, we know that the error, which is caused by secondary winding resistance of the transformer, exists between the two outputs in the steady state characteristics. Furthemore, it is verified that the current-fed DC-to-DC converter has also excellent stability in the multioutput application.

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V/f Control of the SPMSM with stabilizing loop using a reduced order observer (축소차수 관측기를 이용한 SPMSM의 V/f제어)

  • Park, Soon-Je;Kim, Young-Seok
    • Proceedings of the KIEE Conference
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    • 2015.07a
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    • pp.962-963
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    • 2015
  • This paper proposes a sensorless V/f control method of the interior mounted permanent magnet synchronous motor without damper winding. Arithmetic computation is simpler than vector control. And the lower cost price, dynamics and stability is guaranteed. When the loss of synchronization occurs with the load disturbances, the stability loop with a reduced order observer is applied quickly and accurately to improve the speed error.

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Transformer Vibration Analysis for a variation of Load (부하변화에 대한 변압기 진동 분석)

  • 강창구;곽희로;정찬수;조국희;권혁승
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 1993.10a
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    • pp.103-106
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    • 1993
  • This paper describes the modeling of winding vibration for a variation of load and temperature. The structural changes in transformer windings due to heat cause the change of vibration patterns. The vibration signals were detected by the accelerometer on the transformer windings. The real values were compared with estimated value using least-squares method, vibration model was cstablished and with this model, error compared with original signal was less than -50[db]. These results could be applied to diagnosis of incipient failures of the power transformers.

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Experimental Research to Improve the Output Characteristic of CDI System (CDI시스템의 출력발생향상을 위한 실험적 연구)

  • 전병실;김종규
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.31 no.11
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    • pp.146-154
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    • 1982
  • This paper proposes a new circuit for the CDI system to have a constant ignition power at the engine speed range of 500 to 7500 rpm and the battery voltage range of 12 to 16 volts in the 4-cylinder automobile. The proposed CDI system has a closed-loop with a PWM DC-DC converter controlled by the error signal between capacitor voltage and reference voltage. In order to decrease the capacitor charging time, the primary winding of ignition coil is made to be shorted during capacitor charging. An experimental suystem is fabricated and the results obtained thereof are found to be satisfactory.

Tension Control in a Nonlinear Web Transfer System (비선형 웹 이송 시스템의 장력 제어)

  • 윤석찬
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.9 no.5
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    • pp.65-72
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    • 2000
  • This paper presents the study of the tension control in a web transfer system. In this study the sliding mode controller is applied to a time-varying nonlinear mathematical model. The model was derived to consider the effects of changing the roll radius in tension variation during winding and unwinding. The uncertainty in modeling may be due to unmodelled dynamics, on variations in system model. Designed sliding mode controller made the system error always staying in the suggested surface from the beginning. Through this, system is maintained to be robust against a disturbance and uncertainty. To verify the designed controller has a good performance, various inputs such as desired velocity, step input, and trapezoidal input are applied. When the sliding mode controller was used, the system(the tension control) performance was improved comparing to the PID controller. The robustness of the controller with respect to an estimation error was verified through simulations.

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Method for improving the accuracy of a voltage transformer considering hysteresis characteristics (히스테리시스 특성을 고려한 전압 변성기 오차 개선 방법)

  • Kang, Yong-Cheol;Lee, Byung-Eun;Park, Jong-Min;Cha, Sun-Hee;Jang, Sung-Il;Kim, Yong-Guen
    • Proceedings of the KIEE Conference
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    • 2006.07a
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    • pp.208-209
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    • 2006
  • Voltage Transformer is used to transform high voltage into low voltage to input signal of protection relay. Most of the Voltage Transformers use the iron core which maximizes the flux linkage. The ratio of the Voltage Transformer depends on the transformer turns ratio. The current which flows in the Voltage Transformer has non-linear characteristic caused by hysteresis of the iron core, it causes a voltage loss in the winding impedances which makes measurement errors. This paper describes an error compensation method considering hysteresis characteristic. The proposed compensation method improves error by calculating the primary current from the exciting current of the hysteresis loop in the Voltage Transformer, compensating the voltage loss.

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Study on Transformer and Inductor Using Equivalent Air gap to Partial Flux Saturation (국부적 자속 포화 현상을 이용한 리엑터 및 변압기의 공극 등가 모델에 관한 연구)

  • Park, Sung-Jun;Lee, Sang_Hun;Kim, Jeong-Hun
    • Journal of the Korean Society of Industry Convergence
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    • v.17 no.3
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    • pp.103-112
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    • 2014
  • BY the Transformers and reactors, the input electrical energy is converted into magnetic energy. At the end through the magnetic energy was passed at the output parameter. Specially At the flyback transformer or a reactor airgap were designed to contain more magnetic energy. But that work is very difficult for the optimal design. It is that Contradictions are between the length of the Air-gap, Winding inductance, DC bias. As to e Several conflicting conditions in order to determine the optimum Air-gap has a lot of experience and trial & error is necessary. The approach proposed in this paper, the auxiliary winding on the core attached to part of primary core, that by applying a DC voltage has a dramatic effect like Core with designed Air-gap. This inventiveness and advantage is to regulate arbitrarily the Saturation Flux Quantity by the input signal to secondary winding. Accordingly obtained the biggest effect is that increasing limits of the saturation current destined by the material and shape of the conventional core. In other words, that can decreas the size of the transformer and reactor, While maintaining the current saturation capacity. This paper, prove its effect as using the local flux saturation in transformers and reactors for research by the computer program using the finite element method (FEM) simulation, followed by actual experiment to verify

A Simple Negative Torque Compensation Scheme for a High Speed Switched Reluctance Motor

  • Lee, Dong-Hee;Ahn, So-Yeon;Ahn, Jin-Woo
    • Journal of Power Electronics
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    • v.12 no.1
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    • pp.58-66
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    • 2012
  • SRMs(Switched Reluctance Motors) are much interested in high speed applications due to the mechanical robustness, simple structure and high efficiency. In spite of many advantages of SRMs, a higher torque ripple discourages the adoption of SRMs in a high speed application. This paper presents a simple negative torque of tail current compensation scheme using a modified TSF(Torque Sharing Function) for the high speed SRMs. Because of the short commutation in the high speed region, the negative torque from the tail current makes the high torque ripple. In order to reduce and compensate the negative torque from tail current, the proposed control scheme produces an additional compensating torque with a reference torque in the active phase winding. And the compensating value is dependent on the tail current of the inactive phase winding. Furthermore, the switching signals of the outgoing phase are fully turned off to restrict the extended tail current, and the torque error of the outgoing phase is compensated by the incoming phase. The proposed modified TSF control scheme is verified by the computer simulations with 30,000[rpm] high speed 4/2 SRM. The simulation and experimental results show the effectiveness of the proposed control scheme.