• Journal of Electrical Engineering and Technology
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• 제10권2호
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• pp.551-559
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• 2015

This paper's focus is in reducing the torque ripple and increasing the average torque by optimizing switching angles of 8/6 switched reluctance motor while implementing a robust speed controller in the outer loop. The mathematical model of the machine is developed and it is simulated using MATLAB/Simulink. An objective function and constraints are formulated and Optimum turn-on and turn-off angles are determined using Particle swarm optimization and Genetic Algorithm techniques. The novelty of this paper lies in implementing sliding mode speed controller with optimized angles. The results from both the optimization techniques are then compared with initial angles with one of them clearly being the better option. Speed response is compared with PID controller.

• Journal of Electrical Engineering and Technology
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• 제8권5호
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• pp.1062-1069
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• 2013

This paper proposes a simple current compensation method to improve the control performance of B4 inverters. Four-switch inverters so called B4 inverters employ only four switches. They have a split dc-link and one phase of three-phase motors is connected to the center-tap of split dc-link capacitors in B4 inverters. The voltage ripples in the center tap of the dc-link generate unbalanced three-phase voltages causing current ripples. To solve this problem, this paper presents a simple compensation method that adjusts switching times considering dc-link voltage ripples. The validity of the proposed method is verified by simulations and experiments carried out with a 1 HP induction machine.

• 전기학회논문지P
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• 제60권2호
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• pp.94-98
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• 2011

Electrolytic power capacitors today form essential components for virtually any power electronic system such as DC/DC converter or UPS. Frequently, electrolytic capacitors for DC link voltage smoothing are the key components which determine the life cycle of the whole unit and often are responsible for converter breakdown failures. In this paper, ethernet-based remote diagnosis system for DC voltage smoothing capacitor using DSP control board is developed. To estimate the status of the capacitor, the equivalent series resistor(ESR) of the component has to be determined. The ESR detection scheme is based on the determination of the capacitor ripple power losses calculated from DC link voltage/current measurement. Experimental results show the veridity and reliability of the proposed ethernet-based remote on-line capacitor diagnosis system.

• 한국정보통신학회논문지
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• 제8권5호
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• pp.1068-1073
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• 2004

전원장치의 소형화 핵심기술인 반도체 스위칭 기술을 이용하여 5 V/500 mA급 트랜스리스형 파워모듈(transless type power module)을 설계하였다. 파워 모들은 강압형 chopper 방식을 이용하였으며, 스위칭회로, 제어회로, 전압검출회로, 그리고 정전압 회로 등으로 구성되어 었다. 본 연구에서 설계한 스위칭 파워모듈은 0.2 V의 load regulation, 0.1 V의 line regulation, 85 mVp-p의 output ripple 전압, 64.7 kHz의 스위칭 주파수, 최대 58% 정도의 효율을 나타내었으며, 신뢰성 및 EMC 평가항목을 만족하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2004년도 전력전자학술대회 논문집(1)
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• pp.224-227
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• 2004

The goal of this paper is optimal switching angle of switched reluctance motor drive system for maximum energy ratio. A new magnetizing method with a low-frequency increasing the energy conversion ratio that is related to the efficiency of motor is proposed. As results, it improved the efficiency about $2[\%]$. And a torque ripple is also sufficiently reduced compared with that of the conventional switching angle magnetizing approach. In order to start softly regardless of a large ripple torque, the profile of phase current is predicted by the ANFIS, and current control mode was adapted when it is operated under the starting speed. Variable implementations on the fields will guarantee the more practical drive system.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제52권2호
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• pp.80-86
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• 2003

In this paper, a new three-phase voltage-source inverter topology for high voltage and high Power applications is proposed to improve the quality of output voltage waveform. A chain converter which is used as an auxiliary circuit generates a ripple voltage and injects it to the conventional 12-step inverter. Thus, the injection of the ripple voltage results in 36-step operation with a link and 60-step operation with two links. The proposed inverter is compared to the conventional multilevel inverter in the viewpoint of ratings of phase- shifting transformers, switching devices and capacitors employed. The proposed scheme is simple to control capacitor voltages compared to the conventional schems and is cost effective for high voltage and high power application over several tens of MVA. The proposed approach is validated through simulation, and the experimental results are provided from a 2KVA laboratory prototype.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 B
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• pp.974-976
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• 2001

This paper presents a method to reduce commutation torque ripples occurred during commutation in brushless do motor drives using a single DC-link current sensor. In brushless dc motor drives with a single dc current sensor instead of 3-phase line current sensors, it is noted that dc-link current sensor cannot give any information corresponding to the motor currents during line current commutation intervals. A new technique to resolve such a problem is dealt with based on a deadbeat current control in which motor armature voltage command is computed from a dc-link current reference, an actual current and counter emf voltage. The simulation results show that the proposed method reduces the torque ripple significantly.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년 학술대회 논문집 정보 및 제어부문
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• pp.339-341
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• 2006

This paper presents a new method on controller design of brushless dc motors. In such drives the current ripples are generated by motor inductance in stator windings and the back EMF. To suppress the current ripples the current controller is generally used. To minimize the size and the cost of the drives it is desirable to control motors without the current controller and the current sensing circuits. To estimate the motor current it is modeled by a neural network that is configured as an output-error dynamic system. The identified model is essentially a one step ahead prediction structure in which fast inputs and outputs are used to calculate the current output. Using the model, effective estimator to compensate the effects of disturbance has been designed. The effectiveness of the proposed current estimator is verified through experiments.

• 대한전자공학회논문지
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• 제27권8호
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• pp.1255-1259
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• 1990

A new ripple analog-to-digital converter (ADC) has been developed. It consists of two parallel ADCs and a switching network. The circuit operates on the analog input signal in two serial steps. First, a coarse conversion is made to determine the most significant bits by the first parallel ADC. The resultant bits control the switching network to connect a series resistor segment, within which the analog signal is contained, to the second parallel ADC. At second step, a fine conversion is made to determine the least significant bits by the second parallel ADC. The circuit requires 2(2\ulcorner\ulcorner1) comparators, 2(2\ulcorner\ulcorner resistors, and 2(2\ulcorner\ulcorner swithches for N-bit resolution.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.128-128
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• 2010

The high-voltage X-ray generator recently used is very popular, because that can be miniaturized, increased in generating efficiency, elaborated in output control. All these features are available with high-frequency made by using an inverter, the fast switching semiconductor device. In this paper to identify the differences among types of rectification, we compared output ripple with full-wave rectification and dual-voltage rectification methods.