• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.30 no.2
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• pp.26-30
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• 2016

This paper presented an optimum design of a perpendicular PMDSLSM (Permanent Magnet Double-sided Linear Synchronous Motor) to minimize the detent force. As an optimum method, the response surface method was used and 3D finite element method for the calculation. The design variables of the machine were the primary core width and thickness, and magnet width, thickness and length. Object functions were to minimize the detent force and maximize the thrust of the basic model. The results showed that the thrust force of the optimum design increased from 82.1N to 90.2N and detent force decreased from 15.2N to 2.8N, respectively, compared to the basic model.

• Proceedings of the KIEE Conference
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• 1988.11a
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• pp.337-340
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• 1988

This paper describes a fast response control of an inverter-fed induction Motor. The transfer function of the induction Motor controlled by this control method ie very similar to that of a separately exited dc motor. This paper presents the linear control method for the transfer function in the control of an inverter-fed induction motor, Acceding to this control, the response speed is correctly grasped faking the leakage inductances into account and the inverter-fed induction motor is controlled with fast response.

• Journal of Magnetics
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• v.19 no.4
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• pp.385-392
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• 2014

Uncertainties in loads, materials and manufacturing quality must be considered during electromagnetic devices design. This paper presents an effective methodology for robust optimization design based on the variance decomposition in order to keep higher accuracy of the robustness prediction. Sobol' theory is employed to estimate the response variance under some specific tolerance in design variables. Then, an optimal design is obtained by adding a criterion of response variance upon typical optimization problems as a constraint of the optimization. The main contribution of this paper is that the proposed method applies the variance decomposition to obtain a more accurate variance of the response, as well save the computational cost. The performance and robustness of the proposed algorithms are investigated through a numerical experiment with both an analytic function and the TEAM 22 problem.

• Transactions on Control, Automation and Systems Engineering
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• v.2 no.4
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• pp.262-267
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• 2000

In this paper, the magnitude of undershoot and overshoot in a prototype second order system with one positive real zero is computed by the analytic methods. Also, it will be shown that the peak times of the undershoot and overshoot can be calculated using the impulse and step response of the second order system. Three different cases are investigated: underdamped(p<ζ<1), critically damped(ζ=1) and overdamped(ζ>1) cases. We deal with the undamped(ζ=0) case as a special case of the underdamped. And a compensation method is proposed to reduce undershoots of the nonmininmun phase system using feedforward compensator.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.463-465
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• 1997

For fast response of the dc output voltage in PWM converter, the relationship of power balance of both the input and output should be introduced to the system modeling. Then, a nonlinear control theory using state feedback linearization is useful to control the system. By nonlinear control, the voltage response can be fast, so the size of the output filter capacitor can be reduced as long as the same response is kept. The validity of the proposed scheme is shown from the simulation results.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.618-620
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• 1997

A $50{\times}50{\mu}m^2$ aluminum micromirror array is fabricated using shadow evaporation process. The fabrication process is very simple with use of shadow evaporation process, and the micromirror array has a high fill-factor. The static and dynamic characteristics such as deflection angle vs. applied voltage, step response, and frequency response are measured using a contact free optical measurement technique. The downward threshold voltage was 8 V, step response time was $13.5{\mu}s$ when 32 V step voltage applied, and a resonance observed at 11kHz. The lifetime of micromirror with anti-stiction coating was tested and micromirror operated successfully over 200 million cycles of touch-down operations.

• Journal of Electrical Engineering and Technology
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• v.3 no.4
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• pp.499-508
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• 2008

Frequency regulation in off-normal conditions has been an important problem in electric power system design/operation and is becoming much more significant today due to the increasing size, changing structure and complexity of interconnected power systems. Increasing economic pressures for power system efficiency and reliability have led to a requirement for maintaining power system frequency closer to nominal value. This paper presents a decentralized frequency control framework using a modified low-order frequency response model containing a proportional-integral(PI) controller. The proposed framework is suitable for near-normal and emergency operating conditions. An $H_{\infty}$ control technique is applied to achieve optimal PI parameters, and an analytic approach is used to analyse the system frequency response for wide area operating conditions. Time-domain simulations with a multi-area power system example show that the simulated results agree with those predicted analytically.

• Proceedings of the KIEE Conference
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• 1998.07g
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• pp.2527-2529
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• 1998

Measurement equipment, which consists of He-Ne laser, objective lens, CCD camera and position sensitive detector, was developed for the dynamic response of micromirror. This equipment can measure the tilting direction and angle, the rise time and frequency response of micromirror to the input signal. It was found that the rise time of the micromirror was less than 10${\mu}m$ and the resonant frequency was about 25kHz.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.45 no.2
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• pp.283-288
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• 1996

This paper presents the development technology of standard shielded resistor divider for full lightning impulse voltage. The ability of large-capacity power apparatus to withstand lighting stroke is usually evaluated by means of full lightning impulse voltage. Lightning impulse voltage test has been essential to evaluate the insulation performance of electrical power apparatus. Recently international standard (IEC 60) on high voltage measurement techniques is being revised and requests a formal traceability of high voltage measurements. Therefore, general interest for this area has grown considerably during last years, and several international intercomparisons have already completed worldwide, i.e. Europe, Japan, America etc., In this viewpoint, we have also investigated the step response of the standard shielded resistor divider, which satisfies the IEC recommendation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.12
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• pp.1705-1711
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• 2017

This paper analyzes the impact of DRA (Demand Response Aggregator) on market power when competing with power generation companies (Gencos) in the electricity market. If congestion occurs in the transmission line, the strategic choice of the power generation company increases exercise of market power. DRA's strategic reduction of power load impacts the strategy of Gencos, which in turn affects the outcome of the load reduction. As the strategy of Gencos changes according to the location of the congested transmission line, the impact on the market depends on the relative location of the congested line and the DRA.