• The Transactions of the Korean Institute of Power Electronics
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• v.24 no.4
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• pp.294-302
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• 2019

A capacitor common connected LLC resonant converter with auxiliary switches for a wide output voltage control range is presented in this paper. The proposed converter can be controlled in two ways to achieve a wide output voltage control range of Vo-3Vo. The first control method is performed through pulse width modulation of the auxiliary switches and primary switching devices. The second control method is conducted through frequency modulation of the primary switching devices configured to operate in full-bridge switching modes, when the auxiliary switches are turned off. The feasibility of the proposed converter is verified by the experimental results of a 5 kW prototype.

• Journal of the Korean Institute of Intelligent Systems
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• v.22 no.1
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• pp.119-125
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• 2012

This paper proposes a model for a chainless power assistor system(PAS) that can provide the required power based upon operational status by designing a chainless electric bicycle that can be substituted for a general chain type bicycle and which is also an environmentally friendly means of transportation. This paper designed a fuzzy control algorithm that can intelligently examine operational status through the stopping force sensor of a chainless intelligently auxiliary power system it and also have the power of an auxiliary power system to be controlled by the vehicle's operational status. This paper designed an intelligent electric bicycle that provides auxiliary power to a general bicycle system relying only upon the stepping force of a human and systems to provide auxiliary power to the intelligent chainless bicycle model designing presented.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.153-158
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• 1998

In this paper, a prototype of the auxiliary resonant commutated snubber circuit(ARCS) with a high frequency transformer power regeneration loop is described for voltage source type sinewave inverter system. This is a new soft switching topology developed for three phase voltage source soft-switching inverter, active power filter and reactive power compensator has significant advantage of current rating reduction for auxiliary active switching devices. In addition, this paper presents a novel prototype of voltage-source soft switching space vector-modulated inverter with ARCS mentioned above, which is more suitable and acceptable for high-power utility interactive power conditioning, along with a digital control scheme. The steady-state operating analysis of ARCS has the remarkable features and the practical design procedure of this resonant snubber are illustrated on the basis of computer simulation analysis. The operating performance evaluations in the steady-state of this three phase voltage source soft switching inverter are discussed and compared with the three phase voltage source hard switching inverter.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.50 no.3
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• pp.120-130
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• 2001

We present an approach to parallelizing optimal power flow that is suitable for distributed implementation and is applicable to very large interconnected power systems. This approach can be used by utilities to optimize economy interchange without disclosing details of their operating costs to competitors. Recently, it is becoming necessary to incorporate contingency constraints into the formulation, and more rapid updates of telemetered data and faster solution time are becoming important to better track changes in the system. This concern led to a research to develop an efficient algorithm for a distributed optimal power flow based on the Auxiliary Problem Principle and to study the convergence rate improvement of the distributed algorithm. The objective of this paper is to find a set of control parameters with which the Auxiliary Problem Principle (Algorithm - APP) can be best implemented in solving optimal power flow problems. We employed several IEEE Reliability Test Systems, and Korea Power System to demonstrate the alternative parameter sets.

• Journal of Power Electronics
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• v.19 no.1
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• pp.11-23
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• 2019

In this study, a novel zero voltage zero current transition (ZVZCT) bidirectional DC-DC converter is proposed by employing coupled inductors. This converter can turn the main switch on at ZVZCT and it can turn it off with zero voltage switching (ZVS) for both the boost and buck modes. These characteristics are obtained by using a simple auxiliary sub-circuit regardless of the power flow direction. In the boost mode, the auxiliary switch achieves zero current switching (ZCS) turn-on and ZVS turn off. Due to the coupling inductors, this converter can make further efficiency improvements because the resonant energy in the capacitor or inductor can be transferred to the load. The main diode operates with ZVT turn-on and ZCS turn-off in the boost mode. For the buck mode, there is a releasing circuit to conduct the currents generated by the magnetic flux leakage to the output. The auxiliary switch turns on with ZCS and it turns off with ZVT. The main diode also turns on with ZVT and turns off with ZCS. The design method and operation principles of the converter are discussed. A 500 W experimental prototype has been built and verified by experimental results.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.358-361
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• 1999

In auxiliary block of high speed train power factor correction and harmonics reduction is very important issue for efficient energy transport. The GTO-equipped PWM converter is used for traction untill resently. But the rising power capability of IGBTs resently allows to build IGBT-equipped PWM converter with a considerably increased switching frequency. This paper presents switching pattern, control method, operation mode and tuned filter to reduce dc link voltage ripple for paralleled converter.

• Proceedings of the KIPE Conference
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• 1996.06a
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• pp.39-42
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• 1996

This paper proposes a novel Auxiliary Resonant Commutated Pole Inverter (ARCPI) topology. The conventional ARCPIs make the hard switching at turn-off likewise the conventional PWM inverters. Therefore, turn-off switching losses may be so serious and can be so much considerable in high power level. The proposed ARCPI can solve this problem with high frequency transformers, switches, and capacitors. All the switches in the expanded auxiliary circuit achieves the soft switching and operates only during the commutating intervals. The characteristics and the analysis for each operation mode are described in detail and the validity is verified by the simulations and the experimental results.

• Proceedings of the KIPE Conference
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• 2003.07a
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• pp.213-215
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• 2003

This paper presents an instantaneous space vector modulated voltage source type three-phase soft-switching PFC rectifier using a single auxiliary resonant DC Link snubber for alternative energy utilizations. in the first place, the operating principle of an active auxiliary resonant DC link snubber circuit is described including its unique features. In the next place, the simulation analysis of three-phase soft-switching PWM rectifier is implemented, and the operating performances or the three-phase voltage-fed PWM rectifier treated here, which can operate under the conditions of sinewave line current shaping and utility power factor are evaluated and discussed on tile basis of this simulation results.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.413-416
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• 2006

The power source of an AC-PDP fur sustainer circuit is operated in high-voltage and high frequency switching during the process required to achieve the gas discharge current to generate light in a PDP panel. Since PDP has the characteristics of a pure capacitive load, the displacement current that occurs during charge and discharge generates considerable reactive power. An auxiliary circuitry called Energy Recovery Circuit (ERC) reduces the capacitive displacement current. However, this auxiliary topology also bears high stress in its components. In this paper, a multilevel voltage wave shaping sustainer circuit with auxiliary ERC characteristics for an AC-PDP driver is proposed. A comparative analysis and experimental results are presented.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.4
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• pp.212-218
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• 1999

A new partial resonant three phase boost converter with high power factor and high efficiency is proposed. The proposed boost converter is constructed by using a resonant network in parallel with the swithch of the conventional boost converter. The devices are switched at zero voltage or zero current eliminating the switching loss. A new auxiliary partial resonant boost converter achieves zero-voltage switching(ZVS) or zero-current switching(ZCS) for all switch devices without increasing their voltage and current stresses.