• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.2
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• pp.114-122
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• 2004

This paper presents a novel single-stage active-clamp type high frequency resonant inverter. The proposed topology is integrated full-bridge boost rectifier as power factor corrector and active-clamp type high frequency resonant inverter into a single-stage. The input stage of the full-bridge boost rectifier works in discontinuous conduction mode(DCM) with constant duty cycle and variable switching frequency. So that a boost converter makes the line current follow naturally the sinusoidal line voltage waveform. By adding additional active-clamp circuit to conventional class-E high frequency resonant inverter, main switch of inverter part operates not only at Zero-Voltage-Switching mode but also reduces the switching voltage stress of main switch. Simulation results have demonstrated the feasibility of the proposed high frequency resonant inverter. Characteristics values based on characteristics estimation through circuit analysis is given as basis data in design procedure. Also, experimental results are presented to verify theoretical discussion. This proposed inverter will be able to be practically used as a power supply in the fields of induction heating applications, fluorescent lamp and DC-DC converter etc.

• Proceedings of the KIEE Conference
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• 1997.07f
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• pp.2240-2242
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• 1997

A new group of magnetic coupled high power factor converter with a single-switch /single-stage is proposed. The proposed converter gives the good power factor correction, low current harmonic distortions, and tight output voltage regulation. The prototype shows the IEC555-2 requirements are met satisfactorily with nearly unity power factor.

• Proceedings of the KIPE Conference
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• 1996.06a
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• pp.35-38
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• 1996

A new high power factor converter using transformer magnetizing energy for power factor correction with a single-switch/single-stage is proposed. The proposed converter gives the good power factor correction, low current harmonic distortions, and tight output voltage regulation. The prototype shows the IEC555-2 requirements are met satisfactorily with nearly unity power factor.

• Journal of Sensor Science and Technology
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• v.20 no.2
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• pp.77-81
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• 2011

This paper presents a single-pole eight-throw(SP8T) switch based on proposed a radio-frequency(RF) microelectromechanical systems (MEMS) switches. The proposed switch was driven by a double stop(DS) comb drive, with a lateral resistive contact. Additionally, the proposed switch was designed to have tapered signal line and bi-directionally actuated. A forward actuation connects between signal lines and contact part, and the output becomes on-state. A reverse actuation connects between ground lines and contact part, and the output becomes off-state. The SP8T switch of 3-stage tree topology was developed based on an arrangement of the proposed RF MEMS switches. The developed SP8T switch had an actuation voltage of 12 V, an insertion loss of 1.3 dB, a return loss of 15.1 dB, and an isolation of 31.4 dB at 6 GHz.

• Journal of Power Electronics
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• v.2 no.4
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• pp.312-324
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• 2002

This paper presents a new PWM DC/DC converter with dual output power using single power stage, which has the isolation characteristics between each dual output. The proposed converter topology consists of two switches ($S_B$ and $S_F$) and only single secondary winding. Therefore, the proposed converter has better advantages of not only low cost and small size but also high power density because of using minimum components and devices compared with conventional methods which use multi winding transformers or several converters. The operating principle of the proposed converter topology, which includes the conventional auxiliary ZVT (Zero-Voltage-Transition) circuit to implement soft switching of the main switch, is illustrated in detail and the validity of the proposed converter is verified through several simulated and experimental results.

• The Transactions of the Korean Institute of Power Electronics
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• v.3 no.2
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• pp.148-155
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• 1998

A novel single-switch, single-stage, AC/DC forward converter with transformer magnetic energy feedback technique for power factor correction is proposed. The operational principle and analysis of the proposed converter is presented. The proposed converter gives the good power factor correction, low line current harmonic distortions, and tight output voltage regulation. The prototype shows the IEC 555-2 requirements are met satisfactorily with nearly unity power factor.

• Journal of Power Electronics
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• v.4 no.4
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• pp.246-255
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• 2004

Ac-dc PWM single-stage converters that integrate the PFC and dc-dc conversion functions in a single switching converter have been proposed to try to minimize the cost and complexity associated with implementing two separate and independent switch-mode converters. In this paper, two simple ac-dc single-stage PWM full-bridge converters are considered - one current-fed, the other voltage-fed. The operation of both converters is explained and their properties are noted. Experimental results obtained from simple lab prototypes of both converters are presented, then compared and discussed.

• Proceedings of the KIEE Conference
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• 2003.04a
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• pp.270-272
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• 2003

Switching power supplies are widely used in many industrial fields. Power factor correction(PFC) circuits have tendency to be applied in new power supply designs. The input active power factor correction(APFC) circuits can be implemented using either the two-stage approach or the single-stage approach. The single-stage PFC circuit has advantage to reduce the number of components by eliminating a need for the PFC switch and control circuit. However, unlike in the two-stage approach, the do voltage on the energy storage capacitor in a single-stage PFC circuit is not well regulated. As a result. in universal line application($90{\sim}265Vac$), the storage capacitor voltage varies with the load and line variation. In this paper, the performance of output voltage regulation and transient response are clarified here. The validity of designed boost PFC circuit is confirmed by MATLAB simulation and experimental results of 2 [kW] prototype converter.

• Journal of Electrical Engineering and Technology
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• v.11 no.3
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• pp.644-652
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• 2016

This paper presents an improved single-stage ac-dc LED-drive flyback converter using the transformer-coupled lossless (TCL) snubber. The proposed converter is derived from the integration of a full-bridge diode rectifier and a conventional flyback converter with a simple TCL snubber. The TCL snubber circuit is composed of only two diodes, a capacitor, and a transformer-coupled auxiliary winding. The TCL snubber limits the surge voltage of the switch and regenerates the energy stored in the leakage inductance of the transformer. Also, the switch of the proposed converter is turned on at a minimum voltage using a formed resonant circuit. Thus, the proposed converter achieves high efficiency. The proposed converter utilizes only one general power factor correction (PFC) control IC as its controller and performs both PFC and output power regulation, simultaneously. Therefore, the proposed converter provides a simple structure and an economic implementation and achieves a high power factor without the need for any separate PFC circuit. In this paper, the operational principle of the proposed converter is explained in detail and the design guideline of the proposed converter is briefly shown. Experimental results for a 40-W prototype are shown to validate the performance of the proposed converter.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.626-630
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• 1999

A new integrated single-stage zero current switched(ZCS) quasi-resonant converter (QRC) for the power factor correction(PFC) converter is introduced in this paper. The power factor correction can be achieved by the discontinuous conduction mode(DCM) operation of an input current. The proposed converter has the characteristics of the good power factor, low line current harmonics, and tight output regulation. Furthermore, the ringing effect due to the output capacitance of the main switch can be eliminated by use of active clamp circuit.