• Journal of international Conference on Electrical Machines and Systems
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• 제1권2호
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• pp.53-57
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• 2012

The mathematical model of a three-phase voltage source pulse-width modulation (PWM) DC/AC inverter is non-linear, and in view of the traditional linear control strategy it can not meet the requirements of designing a high-performance inverter. What's more, when the loads are not pure resistive loads, the inverter further requires that the controller possess high-performance. This paper proposes a nonlinear control strategy for the inverter called Passivity-based Control. We can alter the inverter model in three-phase abc coordinate to two-phase synchronous rotating dq coordinate for establishing the port-control Hamiltonian (PCH) model for this system. We can control the distribution of energy in the system to achieve the control aim. Simulation results show that the passivity-based control method can make this system possess a level of high-performance that is both robust and dynamic.

• The Transactions of the Korean Institute of Power Electronics
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• 제15권1호
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• pp.75-85
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• 2010

In this paper, a Z-source hybrid active power filter is proposed to compensate the harmonics and reactive power in power distribution system. The proposed system is composed of a 7th harmonics-tuned passive filter and an active power filter with a Z-source inverter topology, while voltage source PWM inverter or current source PWM inverter are applied as the power converter topology of conventional active power filters. The Z-source impedance network along with shoot through capability would ensure a constant DC voltage across the DC link. A polymer electrolyte membrane fuel cell is employed as an compensation DC energy source of the proposed system and its equivalent R-L-C circuit is modeled for simulation. As the compensation and control algorithm of the proposed system, the current synchronous detection algorithm is applied. The simulation analysis by PSIM is performed under the three-phase 220V/60Hz voltage source and 25A nonlinear diode loads. The effectiveness of the proposed the system is verified in the steady and transient states.

• Journal of Electrical Engineering and Technology
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• 제13권1호
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• pp.333-344
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• 2018

This proposed paper aims for the high efficiency contactless power transfer in household dc power distribution. A 300 W five-level diode clamped multi-level converter with 300 Vdc input dc link bus is employed for the power transferring task and the output voltage range is controlled at 48 Vdc. The inner and outer solenoid coils are used for inductive power transfer (IPT) transformer with the 200 kHz switching frequency for designed power density. Therefore, to achieve the converter efficiency above 95%, the LLC series resonant with fundamental harmonic analysis (FHA) and the calculated switching angles are used as an optimized tool for designing the system resonant tank. The validations of this approached topology are illustrated in both MATLAB/Simulink simulation and implementation.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• 제28권4호
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• pp.298-308
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• 2017

This paper presents a Interleaved Buck Converter(IBC) system with Random PWM to reduce electromagnetic noise by harmonics. Swithced mode power supply generally controlled by high switching frequency have a electromagnetic interference(EMI) issue due to the high-voltage/high-current switching to regulate the voltage in buck converter. To solve the problem. we present a novel IBC system with PRBS. IBC system has two active switches with 180 phase difference that controll the cicuit with two PWM signal. IBC system may be disadventageous for the cost due to the addtion of one set of switch, but it has adventages of power distribution, current ripple cancellation, fast transient response, and passive component size reduction. To verify the validity of study, simulation program has been bulit using PSIM and the experimental results of IBC system using RPWM was compared with the conventinal PWM and randomized PWM.

• Journal of the Korean Society of Industry Convergence
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• 제26권6_2호
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• pp.1097-1108
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• 2023

Recently, demand for technology for energy economy and stable supply is increasing due to the increase in power demand of loads. The amount of DC power generation using new and renewable energy is noticeably increasing, and the use of DC power supplies is also increasing due to the increase in electric vehicles and digital loads. During parallel operation to increase the capacity of the power converter, the module bus method or the method using Can communication and serial communication has significant difficulties in smooth operation due to communication time delay for information sharing. Synchronization of information sharing of each power converter is essential for smooth parallel operation, and minimization of communication time delay is urgently needed as a way to overcome this problem. In this paper, a new communication method using pulse width information is proposed as a communication method specialized for parallel operation of power converters to compensate for the disadvantage of communication transmission delay in the existing system. The proposed communication method has the advantage of being easily implemented using the PWM and Capture function of the microcomputer. In addition, the DC/DC converter for DC distribution was verified through simulation and experiment, and it has the advantage of easy capacity expansion when applied to parallel operation of various types of power converters as well as DC/DC converters.

• Journal of Electrical Engineering and Technology
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• 제10권4호
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• pp.1492-1501
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• 2015

This paper analyzes the effect of voltage sag on distribution systems due to the connection of Electric Vehicles (EVs). In order to study the impact of the voltage sag on the power system, two scenarios have been selected in this paper. The distribution system and EVs are modeled using the Electro Magnetic Transients Program (EMTP). The numbers of EVs are predicted based on the number of vehicles in distribution system of Seoul. In addition, the number of EVs is set up using real-time traffic in Seoul to simulate Scenario I and II. The simulation results show that voltage sag can occur if the distribution system has more than 30% of the total number of vehicles.

• Korean System Dynamics Review
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• 제12권3호
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• pp.67-86
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• 2011

This study shows the reduction effect of freight volume by the supply chain redesign for the alliance of distributors with system dynamics simulation. The as-is model is composed of 3 independent companies which one has 3 distribution centers (DCS) and 24 agents, another has 1 dc and 9 agents, the other has 3 DCS and 15 agents each. The to-be model is an integrated logistics model and composed of 1 company having 5 areal DCS and 38 agents. Each agent in the same area is integrated with each other. Two models have same demands but very different result. As a result, the freight volume between DCS and agents is reduced by 33.55%. This case study will be useful to analyze the similar cases about the logistics integration by supply chain redesign.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• 제21권6호
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• pp.123-128
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• 2021

As the spread of DC power distribution systems increases, the occurrence of failures and fire accidents are also increasing. In particular, the ESS fire accident, which is a component of the smart grid, and the fire accident of the solar power system, which is a direct current system, are caused by problems in the electrical connection between system components as the supply of new and renewable energy rapidly increases and old facilities increase. An arc that can cause a direct fire by releasing the induced light and heat has been pointed out as one of the causes of fire. Therefore, the problem of such an arc defect is that it is impossible to block an arc accident in advance with the existing overcurrent circuit breaker and earth leakage circuit breaker. In this paper, we intend to develop a test equipment that satisfies international standardization and to develop a DC arc generator to protect against failure and fire caused by arcing.

• Proceedings of the KIPE Conference
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• 전력전자학회 2013년도 추계학술대회 논문집
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• pp.95-96
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• 2013

In this paper, an operation algorithm for the fuel cell-battery hybrid power system is proposed. As the output current slope of the fuel cell is normally limited to protect the fuel cells' defection, efficient power distribution algorithm between the fuel cell and battery is very important for the successful hybrid control operation. For the experimentation, a 1kW dc-dc converter with 500W fuel cell stack and 1kWh Li-polymer battery is implemented.

• The Transactions of the Korean Institute of Electrical Engineers P
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• 제56권2호
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• pp.90-98
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• 2007

More and All-Electric Aircraft (AEA) carry many loads with varied functions. In particular, there may be large pulsed loads with short duty ratio, which can affect the normal operation of other loads. In this paper, a bi-directional converter with inductive storage is used as a voltage bus conditioner (VBC) to mitigate voltage transients on the bus. In addition, the constant frequency hysteresis control technique for a VBC is presented. A simple and fast prediction of the hysteresis band-width is implemented by the phase-lock loop control, keeping constant switching frequency. This technique offers the excellent dynamic response in load or parameter variation. The control performance is illustrated by simulated results with the SABER package, The proposed hysteresis control results in the shortest and the smallest excursions.