• Journal of IKEEE
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• v.25 no.1
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• pp.218-228
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• 2021

This paper presents the high-efficiency DC-DC converter using the multi-resonant-circuit. The proposed converter has the power topology of half-bridge and utilizes the multi-resonant-circuit that is composed of 2 inductors (LL) and 1 capacitor (C) to achieve high-efficiency. The multi-resonant-circuit forms each resonant circuit of series circuit type with each resonant frequency, according to the operation modes. This paper first describes the operation pirinciples of proposed converter by the operation modes and steady-state fundamental approximation modelling. Then it shows a design example of the proposed converter based on the principles. And it is validated that the proposed converter has the operation characteristics of high-efficiency DC-DC power conversion through the experimental results of prototype converter implemented by the designed circuit parameters.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.12 no.3
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• pp.114-123
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• 1998

The multi-resonant converter(MRC) minimizes a parasitic oscillation by using the resonant tank circuit absorbed parasitic reactances existing in a converter circuit. So it si possible that the converter operated at a high frequency has a high efficiency because the losses are reduced. Such a MHz high frequency applications provide a high power density [W/inch3] of the converter. But the resonant voltage stress across a switch of the resonant tank circuit is 4~5 times a input voltage. This h호 voltage stress increases the conduction loss because of on-resistance of a MOSFET with higher rating. Thus, in this paper we proposed the alternated multi-resonant converter (AT MRC) differ from the clamp mode multi-resonant converter and applicated it to the forward MRC. The AT forward MRC can reduce the voltage stress to 2~3 times a input voltage by using two series input capacitor. The control circuit is simple because tow resonant switches are driven directly by the output pulse of the voltage controled oscillator. This circuit type is verified through the experimental converter with 48V input voltage, 5V/50W output voltage/power and PSpice simulation. the measured maximum voltage stress is 170V of 2.9 times the input voltage and the maximum efficiency of 81.66% is measured.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.7
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• pp.1250-1254
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• 2007

The multi-resonant(MR) converter has a characteristics that the parasitic components existing in the converter are absorbed into the resonant circuits. The designed MR converter could be got a high efficiency and a high power density because the switching power losses are reduced effectively due to resonant switching circuit. However, the high resonant voltage stress of switching power devices leads to the conduction loss. In this paper, it is proposed the novel alternated(AT) flyback multi-resonant converter to overcome such a drawback. The suggested converter dc input is divided by two series input filter capacitors. The resonant stress voltage is reduced to 2-3 times the input voltage without any complexity and it provides the various circuit schemes in lots of applications. The proposed flyback MR converter is verified through simulation and experiment.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.1065-1066
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• 2006

The multi-resonant converter minimizes the parasitic oscillations using the resonant tank circuit absorbed parasitic reactances in a converter. So the converter can be operated at a high frequency and it provides a high efficiency because the switching power losses are reduced effectively. However, the high resonant voltage stress of semiconductors leads to the conduction loss. In this paper, it is proposed the novel flyback multi-resonant converter. The converter input is divided by two series input capacitors. And also the resonant stress is reduced to 2-3 times input voltage without any complexity and it provides the various circuit schemes in lots of applications. The proposed converters are verified through simulation and experiment.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.4
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• pp.71-78
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• 2005

This paper proposes a novel multi-level energy recovery sustaining driver for AC PDP(Plasma Display Panel), which solves the problems of the conventional multi-level sustaining driver. While the conventional circuit improves the voltage md current stress of the switching elements in Weber circuit not only there are parasitic resonant currents between resonant inductors and parasitic capacitance and hard switching, but also the changing period between 0 and sustain voltage is too long. Comparing the proposed circuit with the conventional circuit, the number of components are reduced and the parasitic resonant currents in resonant inductors are eliminated Moreover the hard switching problem is solved by using CIM(Current Injection Method) and the operating frequency will be high as much as possible by removing Vs/2 sustain period. And the circuit operations of the proposed circuit are analyzed for each mode and the validity is verified by the simulations using PSpice program.

• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.2
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• pp.194-202
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• 2005

This paper proposes a new multi-level energy recovery sustaining driver for AC PDP(Plasma Display Panel), which solves the problems and maintains the merits of the conventional multi-level sustaining driver. While the conventional circuit improves the hard switching in the Weber circuit, there exist parasitic resonant currents in resonant inductors and Vs/2 sustaining period. Comparing the proposed circuit with the conventional circuit, the number of inductors are reduced by half, the parasitic resonant currents in resonant inductors are eliminated, and the hard switching problem is solved by CIM(Current Injection Method). Moreover the voltages across series-connected switching elements in the full bridge circuit are distributed equally by adopting NPC(Neutral Point Clamping) techniques. And circuit operations of the proposed circuit are analyzed for each mode and the validity is verified by the simulations using PSpice program and experimentation with a prototype drive circuit.

• The Transactions of the Korean Institute of Power Electronics
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• v.18 no.5
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• pp.458-465
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• 2013

This paper proposes a novel soft-switched auxiliary resonant circuit to provide a Zero-Voltage-Transition at turn-on for a conventional PWM boost converter in a PFC application. The proposed auxiliary circuit enables a main switch of the boost converter to turn on under a zero voltage switching condition and simultaneously achieves both soft-switched turn-on and turn-off. Moreover, for the purpose of an intelligent multi-chip power module fabrication, the proposed circuit is designed to satisfy several design constraints including space saving, low cost, and easy fabrication. As a result, the circuit is easily realized by a low rated MOSFET and a small inductor. Detail operation and the circuit waveform are theoretically explained and then simulation and experimental results are provided based on a 1.8 kW prototype PFC converter in order to verify the effectiveness of the proposed circuit.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1380-1382
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• 2005

The multi-resonant converter minimizes a parasitic oscillation by using the resonant tank circuit absorbed parasitic reactance existing in a converter circuit. So it is possible that the converter operated at a high frequency has a high efficiency because the losses are reduced. However, the resonant voltage stress across a switch is four or five times a input voltage. This high voltage stress increases the conduction loss. In this paper, we proposed the AT flyback multi-resonant converter. The proposed converter can reduce the voltage stress to two or three times by using two series input capacitors. The operational principle of the proposed converter was verified through the experimental converter.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.55 no.6
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• pp.314-324
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• 2006

In recent years, having the advantages of being small, low in cost and high in efficiency, Half-wave resonant type, (having only one output diode), is used in ZVS Half-Bridge DC/DC converter. This paper presents the operation mode by multi-resonant factors in the Half-wave type multi-resonant converter with direct Buck chopper circuit operated in discontinuous current mode. To study the characteristics of a multi-resonant operation in steady-state, the characteristic impedances in each mode and safe operation-region(S.O.R) are reported. Computer simulation and experimental data are also riven to verify the theoretical results.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2000.11a
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• pp.70-76
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• 2000

In the charge system, a contact type-convenient-charging method is insufficient because of the contact failure around moist environment and troublesome question to put in and pull out. For the solution of this problem, an electromagnetically coupled non-contact charger for the rechargeable cell is proposed using ZVS multi-resonant forward converter with synchronous rectifier. In this paper coupling coefficient(k), leaking inductance, coupling inductance and resonant frequency are observed for the air gap. By using the observed value, this circuit is designed and implemented. This proposed circuit is simulated by the PSPICE and experimented. The stress of a main switch and the output power are measured.