• Proceedings of the KIEE Conference
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• 2002.06a
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• pp.125-130
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• 2002

This paper examines the application of high voltage static var compensator(SVC) with cascade multilevel inverter which employs H~bridge inverter(HBI). The SVC system is modeled using the d-q transform which calculates the instantaneous reactive power. This model is used to design a controller and analyze the SVC system. From the mathematical model of the system, the design procedures of the circuit parameters Land C are presented in this thesis. To meet the specific total harmonic distortion(THD) and ripple factor of the capacitor voltage, the circuit parameters Land C are designed. Simulated and experimental results are also presented and discussed to validate the proposed schemes.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.10
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• pp.658-664
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• 2015

This paper presents an electrical feature analysis of hysteresis curves in memristor differential and intergral control circuit. After making macro model of the memristor device, electric characteristics of the model such as time analysis, frequency dependent DC I-V curves were performed by PSPICE simulation. Also, we made a circuit of memristor-capacitor based on nano-wired memristor device and analyzed the simulated PSPICE results. Finally, we proposed a memristor based differential or integral control circuit, analyzed hysteresis curve characteristic in the control circuit.

• Proceedings of the KIEE Conference
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• 1994.11a
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• pp.72-74
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• 1994

This paper presents a linear quadratic gaussian(LQG) based power system stabilizer(PSS) to control subsynchronous resonance(SSR) that occurs in a series capacitor compensated power systems. The complete SSR system based on the IEEE first benchmark model is employed in this study. Eigenvalue analysis and time domain simulations using a nonlinear system model show that the proposed PSS controls SSR efficiently.

• Journal of Welding and Joining
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• v.24 no.3
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• pp.34-41
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• 2006

The CD (Capacitor Discharge) stud welding utilizes the arc heat and pressure to attach the stud to the workpiece, which consists of the arc. ignition, arcing and pressure welding stages. In order to predict the dynamic behavior of the CD stud welding process, mechanical and electrical models are employed in this work. While the mechanical model estimates the duration of each stage, the electrical model predicts the voltage and current waveforms using the RLC circuit. Effects of process parameters such as the electric components and spring force are analyzed through simulation. It is found that the contact resistance and gap between the stud and base metal influence the tip fusing and arcing duration. The calculated results showed reasonably good agreements with the experiment results.

• Journal of the Korea Society of Computer and Information
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• v.7 no.3
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• pp.56-59
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• 2002

In this study, new serial and parallel resistor and capacitor-frequency-dependent negative resistance configurations are implemented that use one plus type four-terminal floating nullor(FTFN) and three passive components. The values of simulated elements can be orthogonally adjusted without any matching condition. High pass filter designed with this FTFN and AD844. Computer simulation was performed using the AD844 macro model by HSPICE. Simulated results agree well with theoretical values.

• Journal of Science Education
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• v.46 no.2
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• pp.212-221
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• 2022

In this study, we propose an analytical model to elucidate the formation of electric fields between two parallel conducting plates. Using nine Gaussian surfaces, we investigated the charge redistributions and electric fields formed by parallel conducting plates when two charged plates get close together. The electric charges are redistributed via a new electrostatic equilibrium to create the electric field of each plates. As a result, the electric field start from + electrode plate to - electrode plate via inducing a new electrostatic equilibrium, implying that the application of Gaussian surfaces to only one of the electrodes of parallel-plate capacitors is deserved. The results will help undergraduate students understand the charge redistribution and the electric field formation in parallel-plate capacitors in a reasonable manner.

• Journal of Power Electronics
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• v.15 no.6
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• pp.1456-1467
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• 2015

This paper presents a novel close-loop control scheme based on small signal modeling and weighted composite voltage feedback for a three-phase input and single-phase output Matrix Converter (3-1MC). A small non-polar capacitor is employed as the decoupling unit. The composite voltage weighted by the load voltage and the decoupling unit voltage is used as the feedback value for the voltage controller. Together with the current loop, the dual-loop control is implemented in the 3-1MC. In this paper, the weighted composite voltage expression is derived based on the sinusoidal pulse-width modulation (SPWM) strategy. The switch functions of the 3-1MC are deduced, and the average signal model and small signal model are built. Furthermore, the stability and dynamic performance of the 3-1MC are studied, and simulation and experiment studies are executed. The results show that the control method is effective and feasible. They also show that the design is reasonable and that the operating performance of the 3-1MC is good.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.51 no.4
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• pp.175-185
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• 2002

In this paper, a new fully digital current control method of UPS inverter, which is based on an internal model control, is proposed. In the proposed control system, overshoots and oscillations due to the computation time-delay are compensated by explicit incorporation of the time-delay in the current control loop transfer function. The internal model controller is adopted to a second order deadbeat reference-to-output response which means that its response reaches the reference in two sampling time including computational time-delays. That is, the average current of filter capacitor is been exactly equal to the reference current with a time lag of two sampling intervals. Therefore, this method has an essentially overshoot free reference-to-output response with a minimum possible rise time. The effectiveness of the proposed control system has been verified by the simulation and experimental respectively. From the simulation and experimental results, the proposed system is achieved the robust characteristics to the calculation time delay and parameter variation as well as very fast dynamic performance, thus it can be effectively applied to the power supply for the critical load.

• Journal of international Conference on Electrical Machines and Systems
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• v.1 no.4
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• pp.434-439
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• 2012

This paper presents a nontraditional laser power system in which an active compensated pulsed alternator (ACPA) drives a flashlamp directly without the use of capacitor groups. As a result, the volume of the laser system is decreased because of the high energy density of the ACPA. However, the difficulty in matching the output of the alternator with the laser flashlamp is a significant issue and needs to be well analyzed. In order to solve this problem, based on the theory for ACPA, the authors propose a simplified model for the system of ACPA with flashlamp load by the way of circuit simulation. The simulation results preliminarily illuminate how the performance of the ACPA laser power system is affected. Meanwhile, the simulation results can also supply a consultation for future ACPA laser power system design and control.

• Journal of Electrical Engineering and Technology
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• v.13 no.4
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• pp.1566-1577
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• 2018

This paper presents a stability analysis of AC-DC power system feeding a speed controlled DC motor in which this load behaves as a constant power load (CPL). A CPL can significantly degrade power system stability margin. Hence, the stability analysis is very important. The DQ and generalized state-space averaging methods are used to derive the mathematical model suitable for stability issues. The paper analyzes the stability of power systems for both speed control natural frequency and DC-link parameter variations and takes into account controlled speed motor dynamics. However, accurate DC-link filter and DC motor parameters are very important for the stability study of practical systems. According to the measurement errors and a large variation in a DC-link capacitor value, the system identification is needed to provide the accurate parameters. Therefore, the paper also presents the identification of system parameters using the adaptive Tabu search technique. The stability margins can be then predicted via the eigenvalue theorem with the resulting dynamic model. The intensive time-domain simulations and experimental results are used to support the theoretical results.