• The Transactions of the Korean Institute of Power Electronics
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• v.2 no.3
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• pp.11-19
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• 1997

본 논문에서는 스위치드 리럭턴스 전동기의 토크 리플 또는 소음을 감소하기 위한 방법으로써 순시 전압제어방식을 제시하였다. 이 방식은 상 정류의 제곱의 합ㅇ르 제어하여 토크 리플을 제거할 수 있다. 제안방식에 대해 해석하였으며, 이 방식의 이론적인 타당성을 입증시키기 위해 소프트웨어 페키지 ASCL에 의해 시뮬레이션하였다. 실험에 의해 SRM 토크 리플의 제거를 확인하였다.

• Journal of Electrical Engineering and Technology
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• v.3 no.1
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• pp.68-78
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• 2008

This paper introduces a complete package for SRM drive on Power System Computer-Aided Design/Electromagnetic Transients (PSCAD/EMTDC). A three-phase SRM drive is modeled and simulated on PSCAD. The motor is modeled using an accurate nonlinear analytical model that takes into consideration the machine nonlinearities. A current control algorithm is applied for torque ripple minimization to achieve a smooth output torque which is necessary for high performance applications. The motor drive is tested for four-quadrant operations. The modeled SRM is capable of operating as a motor or generator during clockwise and counterclockwise motions. The proposed package helps in understanding the operational principles of switched reluctance motors, investigating the dynamic characteristics of SRM drives, and achieving a high performance dynamic control task.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.142-145
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• 2001

In this paper the electromagnetic torque developed in IPMSM(Interior Permanent Magnet Synchronous Motor) is analyzed. If flux distributions in the motor are not sinusoidal, a sinusoidal current produces important torque ripple. Torque ripple causes vibration and noise of motors. The optimized current waveforms for ripple free is able to be obtained by analysis of Back-EMF and torque equation. The method to find the optimal current is based on numerical predetermination. In this paper proposes current waveform which can eliminate the torque ripple, and the validity is verified through the simulation.

• Proceedings of the KIPE Conference
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• 1997.07a
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• pp.322-331
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• 1997

In this paper, Instantaneous voltage control method is proposed to reduce the torque ripple of a switched reluctance motor. This method is based on the sum control of the square of the phase currents in proposed converter. A proposed prototype SRM drive circuit is given and it's operation is analyzed. The experiments and simulations are performed to verify the capability of proposed principle.

• Proceedings of the KIPE Conference
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• 1998.07a
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• pp.197-199
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• 1998

A neuro-fuzzy based torque profile model of SRM with considerably improved accuracy is obtained using the measured data for training. The inferred torque profiles, which comprise magnetic non-linearities, represent the dynamic model of SRM. Then the reference torque signal with optimized waveform and switching angle are decided to control the torque directly. Hence, the presented scheme controls the torque in an instantaneous basis, allowing powerful torque control with minimum torque ripple even during the transient operation of the motor. Simulation and experimental results demonstrating the effectiveness of the proposed torque control scheme are presented.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.476-481
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• 1998

In this paper, a commutation torque minimization method using parameter observer for a brushless DC motor fed by a voltage source inverter is described. In order to investigate the nature of the commutation torque ripple in trapezoidal brushless DC motor, a new model of the motor is proposed. The optimal drive voltage to minimize the ripple torque is represented as a function of the motor parameters. Therefore, the important parameter is estimated by least-square algorithm.

• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.383-384
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• 2015

This paper presents a new space vector modulation (SVM) method for indirect matrix converters (IMCs) to reduce commonmode voltage as well as minimize output current ripple in a high voltage transfer ratio. In the proposed SVM, the three-vector modulation scheme is used in the rectifier stage, while the nonzero state modulation technique, where the three nearest active vectors are selected to synthesize the desired output voltage, is applied to inverter stage to reduce the CMV. The proposed SVM method can significantly reduce the output current ripple and common-mode voltage of the IMC without any extra hardware. Simulated results are provided to demonstrate the effectiveness of the proposed SVM method.

• Journal of electromagnetic engineering and science
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• v.12 no.4
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• pp.290-292
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• 2012

This paper proposes a setup for a best multisine design method that uses a time-domain optimization. The method is based on minimization of the time-domain error, so its resulting multisine has a very accurate ACLR estimation. This is because its probability distribution and sample-to-sample correlation are close to those of the original signal, which are crucial for the testing of nonlinear power amplifiers. In addition, a hyperbolic-tangent function is introduced to control the ripple of tone magnitudes within signal bandwidth. For the verification, multisines were generated and compared for many aspects such as normalized error, in-band ripple, and ACLR estimation. Test results with different numbers of tones provide supporting evidence that the suggested multisine design has better ripple suppression, by up to 7 dB, and better accuracy, by up to 0.2 dB, when compared to the conventional method. The accuracy of the ACLR was improved by about 5 dB when the number of tones was 4. The suggested method improves the ACLR estimation performance of multisine testing due to its closer resemblance to the target modulation signal.

• Journal of Power Electronics
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• v.13 no.6
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• pp.1032-1041
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• 2013

This paper investigates control algorithms for a doubly fed induction generator with a back-to-back three-level neutral-point clamped voltage source converter in medium voltage wind power systems under unbalanced grid conditions. Three different control algorithms to compensate for unbalanced conditions have been investigated with respect to four performance factors; fault ride-through capability, instantaneous active power pulsation, harmonic distortions and torque pulsation. The control algorithm having a zero amplitude of torque ripple shows the most cost-effective performance concerning torque pulsation. The least active power pulsation is produced by the control algorithm that nullifies the oscillating component of the instantaneous stator active and reactive powers. A combination of these two control algorithms depending on the operating requirements and the depth of the grid unbalance presents the most optimized performance factors under generalized unbalanced operating conditions leading to high performance DFIG wind turbine systems.

• The Transactions of the Korean Institute of Power Electronics
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• v.7 no.3
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• pp.297-302
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• 2002

The direct torque control(DTC) of induction machines has the advantages of a simple control scheme and a very quick and robust torque response and its application is extended in the traction field. However, some drawbacks of the conventional DTC strategy using a hysteresis controller are the relatively large torque ripple in the steady state and the variation of switching frequency according to the amplitude of hysteresis bands and the motor operating conditions. In this paper, a navel direct t()roue control scheme of induction machines based on stator flux control and Space Vector Modulation Is proposed to acquire the advantage of a fixed switching period and the minimization of the torque and stator current ripple in a wide speed range. The effect of proposed method has been proven by simulations and experiments.