• 제어로봇시스템학회논문지
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• 제5권7호
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• pp.862-867
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• 1999

In general, the realization of high performance brushless permanent magnet motors which are widely used in servo drive is focused on the linear control for ripple-free torque. This is also the main problem that should be solved in all AC motors including induction motor to achieve high performance control, and recent papers deal with this problem. In this paper, the novel optimal excitation scheme of brushless permanent magnet motor producing loss-minimized ripple-free torque based on the d-q-0 reference frame is presented including 3 phase unbalanced condition. The optimized phase current waveforms that are obtained by the proposed method can be a reference values and the motor winding currents are forced to track it by delta modulation technique. As a results, it can be shown that the proposed work can minimize the torque ripple by the optimal excitation current for brushless permanent magnet motor with any arbitrary phase back EMF waveform. Simulation and experimental results prove the validity and practical applications of the proposed control scheme.

• 전력전자학회논문지
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• 제11권6호
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• pp.551-557
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• 2006

교류 전동기는 전류의 측정오차와 데드타임(dead time) 등의 영향으로 전기각주파수에 동기된 주기적인 토크리플이 발생한다. 본 논문에서는 주기적인 토크리플 보상알고리즘을 제안한다. 보상기는 토크리플에 의해 생성된 속도리플의 크기을 관측하는 속도리플 관측기와 관측한 양으로 토크리플을 보상하는 토크리플 보상기로 나누어진다. 본 논문에서는 토크리플 보상기의 해석을 통해 정상상태에서 속도리플이 제거되고 새롭게 제안된 속도리플 관측기을 적용하여 성능이 향상됨을 보였다. 제안한 주기적인 토크리플 보상알고리즘에 의해 토크리플 성분이 보상됨을 모의 실험과 실험을 통해 검증하였다.

• 전기학회논문지
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• 제57권6호
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• pp.1003-1011
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• 2008

In this paper, optimal design of interleaved boost converters is studied in order to design low ripple, size, loss and high performance converters for fuel cell applications. Also, the process of optimal design of interleaved boost converter has been performed. Input current ripple, output voltage ripple, losses and capacity of electrical components are theoretically analyzed and informative simulation and experimental results are provided.

• 한국안전학회지
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• 제12권4호
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• pp.63-69
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• 1997

This paper presents a design method for a filter application in a parts-of FA(Factory Automation). Normal equations for ripple voltage and current are derived in terms of dimensionless quantities, and these equations can be used directly to evaluate the values of LC-filter components, taking into consideration the effect of the ripple components on the rms value of the PWM-generated ripple components. Using describing function technique, design equations of the filter are derived. The data needed for the filter evaluation are the amplitude of current ripple and the frequency of square pulses delivered by the HE(Harmonic Elimination) inverter algorithm. Experimental results show that the design of the filter can be based on the method proposed and that the filter can provide a significant reduction of ripple components.

• 전력전자학회논문지
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• 제27권1호
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• pp.33-39
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• 2022

A multi-phase brushless direct current (BLDC) motor is widely used in large-capacity electric propulsion systems such as submarines and electric ships. In particular, in the field of military submarines, the polyphaser motor must suppress torque ripple in various failure situations to reduce noise and ensure stable operation for a long time. In this paper, we propose a polyphaser current control method that can improve efficiency and reduce torque ripple by minimizing the increase in stator winding loss at maximum output torque by controlling the phase angle and amplitude of the steady-state current during open circuit failure of the stator winding. The proposed control method controls the magnitude and phase angle of the healthy phase current, excluding the faulty phase, to compensate for the torque ripple that occurs in the case of a phase open failure of the motor. The magnitude and phase angle of the controlled steady-state current are calculated for each phase so that copper loss increase is minimized. The proposed control method was verified using hardware-in-the-loop simulation (HILS) of a 12-phase BLDC motor. HILS verification confirmed that the increase in the loss of the stator winding and the magnitude of the torque ripple decreased compared with the open phase fault of the motor.

• Journal of Power Electronics
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• 제16권5호
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• pp.1851-1860
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• 2016

The traction motors in electric multiple unit (EMU) trains are powered by AC-DC-AC converters, and the DC link voltage is generated by single phase PWM converters, with a fluctuation component under twice the frequency of the input catenary AC grid, which causes fluctuations in the motor torque and current. Traditionally, heavy and low-efficiency hardware LC resonant filters parallel in the DC side are adopted to reduce the ripple effect. In this paper, an analytical model of the ripple phenomenon is derived and analyzed in the frequency domain, and a ripple control scheme compensating the slip frequency of rotor vector control systems without a hardware filter is applied to reduce the torque and current ripple amplitude. Then a relatively simple discretization method is chosen to discretize the algorithm with a high discrete accuracy. Simulation and experimental results validate the proposed ripple control strategy.

• Journal of Electrical Engineering and Technology
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• 제13권6호
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• pp.2553-2560
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• 2018

In Korea, there are no instances where a hydrogen fuel cell power generation system has been used in a railway vehicle. Only the basic topology has been studied. In the previous study, conventional converters using a single switch were applied to the fuel cell power generation system. Therefore, current stress on the switch at converter on-off transitions would be large when controlling a large-capacity railway vehicle. In addition, since the input side ripple is also large, there is a problem with a shortening of the lifetime of both the fuel cell power generation system and the inductor. In this paper, a soft-switching transformer inductor boost converter for fuel cell powered railway vehicles was proposed. A technique to reduce both the switching current stress generated during on-off transitions, and the input ripple current flowing in the inductor were studied. The soft-switching TIB converter uses a transformer-type inductor to configure the entire circuit in an interleaved method, and reduces both input current ripple and the current ripple of the inductor and switch.

• Journal of Power Electronics
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• 제13권3호
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• pp.339-348
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• 2013

Multiphase dc-dc converters are widely used in modern power electronics applications due to their advantages over single-phase converters. Such advantages include reduced current stress in both the switching devices and passive elements, reduced output current ripple, and so on. Although the output current ripple of a converter can be significantly reduced by virtue of the interleaving effect, the inductor current ripple cannot be reduced even with the interleaving PWM method. One way to solve this problem is to use a coupled inductor. However, care must be taken in designing the coupled inductor to maximize its performances. In this paper, a detailed analysis of a coupled inductor is conducted and the effect of a coupled inductor on current ripple reduction is investigated extensively. From this analysis, a UU core based coupled inductor structure is proposed to maximize the performance of the coupled inductor.

• 한국산업융합학회 논문집
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• 제23권6_2호
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• pp.989-998
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• 2020

Recently, demands for large-capacity electronic loads are increasing in various industries such as a reliability test for the performance of a DC power supply device or a dummy-load for improving the stability of an independent microgrid to be actively built in the future. The electronic load required in these various fields requires an operation such as a continuously variable resistance load while minimizing the switching harmonic component generated in the electric load current in order to reduce the influence of interference from the load peripheral device. Electronic loads require a system that minimizes switching current ripple for load control. Therefore, in this paper, we propose a three-level module converter structure to reduce the current ripple of an electronic load, and a multilevel interleaved power converter topology to reduce the current ripple. The validity of the proposed electronic load, 3-level 6 interleaver converter, was verified by simulation and experiment. In addition, the user's convenience was provided by applying the emotional command curve interface method.

• 전기학회논문지P
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• 제61권3호
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• pp.122-128
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• 2012

An interleaved boost converter has many advantages such as current ripple reduction, switching effective double, etc. Due to these advantages, the interleaved boost converter applies to the power factor correction circuit. However, there are almost no analysis results because the input voltage and current are time-varying system in the power factor correction application. Therefore, in this paper, the current ripples of the power factor correction circuit using single-phase boost dc-dc converter and 2-phase interleaved boost dc-dc converter are compared and analyzed in detail. In order to verify the validity, computer simulation and experimental are performed.