• Journal of Power Electronics
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• v.7 no.4
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• pp.301-309
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• 2007

The flyback converter is one of the most attractive isolated converters in small power applications because of its simple structure. However, it suffers from high device stress, large transformer size, and high voltage stress across its switch and diode. To solve these problems a new cost-effective PWM single-switch isolated converter is proposed. The proposed converter has no output filter inductor, reduced voltage stress on the secondary devices, and reduced transformer size. Moreover, the switch turn-off loss is reduced and no dissipative snubber across the secondary diode is required. Therefore, it features a simple structure, a low cost, and high efficiency. The operational principle and characteristics of the proposed converter are presented and compared with the flyback converter and then verified experimentally.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.669-672
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• 2001

Generally, previous converter is divided into two categories to get high power factor and good output regulation. These two categories can be combined a category with a main switch. These converter is called Single Stage PFC Converter. This approach has good electrical characteristics of high power factor and fast output voltage regulation. The cost and size are important factor to design the converter in low power system. Even single stage can reduce the size and cost, but this approach needs to have additional circuit like control, PWM circuit. To improve these demerits, Top switch is one of good choice In reduce and size in low power single stage converter. Because it has the ability of current limit, thermal protection, oscillator, control circuit as well as a main switch ability.

• 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.

• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.6
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• pp.561-568
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• 2011

This paper describes the operation characteristic of a single-phase PFC converter with 1-switch voltage doubler strategy for single-phase double-conversion UPS. A single-phase PFC converter with 1-switch voltage doubler strategy needs a diode bridge and one bidirectional active switch. Thus it is possible to reduce the material cost. However, the study results of operation characteristic and controller design has not been known after the converter circuit was proposed. For the performance evaluation of PFC converter, single-phase 3kVA double-conversion UPS was tested. The performance of PFC converter is experimentally confirmed with followings - input current reference traking, input power factor correction.

• The Transactions of the Korean Institute of Power Electronics
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• v.17 no.1
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• pp.1-7
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• 2012

This paper describes the performance comparison results for current controller of a single-phase PFC converter with 1-switch voltage doubler strategy for single-phase double-conversion UPS(Uninterruptible Power Supply). A single-phase PFC converter with 1-switch voltage doubler strategy needs a diode bridge and one bidirectional active switch. Thus it is possible to reduce the material cost. However, the study results of current controller design and comparison of current control method has not been known after the converter circuit was proposed. For the performance comparison of current control, single-phase 3 kVA double-conversion UPS was tested. The performance of PI and PR current controller is experimentally confirmed with followings - input current reference tracking, input power factor correction and input current THD suppression.

• Journal of Power Electronics
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• v.18 no.1
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• pp.11-22
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• 2018

This paper presents a single switch, high step-up, non-isolated dc-dc converter suitable for renewable energy applications. The proposed converter is composed of a coupled inductor, a passive clamp circuit, a switched capacitor and voltage lift circuits. The passive clamp recovers the leakage inductance energy of the coupled inductor and limits the voltage spike on the switch. The configuration of the passive clamp and switched capacitor circuit increases the voltage gain. A wide continuous conduction mode (CCM) operation range, a low turn ratio for the coupled inductor, low voltage stress on the switch, switch turn on under almost zero current switching (ZCS), low voltage stress on the diodes, leakage inductance energy recovery, high efficiency and a high voltage gain without a large duty cycle are the benefits of this converter. The steady state operation of the converter in the continuous conduction mode (CCM) and discontinuous conduction mode (DCM) is discussed and analyzed. A 200W prototype converter with a 28V input and a 380V output voltage is implemented and tested to verify the theoretical analysis.

• Proceedings of the KIEE Conference
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• 2006.04b
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• pp.247-250
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• 2006

This paper presents the single-stage High Power Factor TSFC(Two-Switch Forward Converter). Recently, due to growing concern about the harmonic pollution of power distribution systems and the adoption of standards such as ICE 61000-3-2 and IEEE 519, There is a need to reduce the harmonic contents of AC line currents of power supplies. This research proposed the single-stage two switch forward circuit for low voltage and high current output. The principle of operation, feature and design considerations are illustrated and verified through the experiment with a 200W(5V, 40A) 200kHz MOSFET based experimental circuit.

• Proceedings of the KIEE Conference
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• 2006.10d
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• pp.169-172
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• 2006

This paper presents the single-stage High Power Factor AC/DC Two-Switch Forward Converter (TSFC). Recently, due to growing concern about the harmonic pollution of power distribution systems and the adoption of standards such as ICE 61000-3-2 and IEEE 519, There is a need to reduce the harmonic contents of AC line currents of power supplies. This research proposed the single-stage two switch forward circuit for low voltage and high current output. The principle of operation, feature and design considerations are illustrated and verified through the simulation with a 200W(5V, 40A) 200kHz MOSFET based experimental circuit.

• Journal of Electrical Engineering and Technology
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• v.4 no.2
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• pp.287-291
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• 2009

In this paper, an optical switch/modulator is designed and its light propagating characteristics analyzed using a simplified BPM. The distinctive feature of this switch/modulator is that all its waveguide branches are designed as single-mode. The principle of the device is based on the coupled mode theory in the Y-junction interconnecting waveguide. In spite of the fact all waveguides are designed as single-mode, by adjusting the interconnecting waveguide length'of the device the same characteristics as existing up to date devices are obtainable. Numerical results show that the switching characteristics periodically depend upon an interconnecting waveguide length with a spatial of about $150^{{\mu}m}$ in the $Ti:LiNbO_3$ step index waveguide. The design concept would therefore be utilized effectively in fabricating a monolithic high density optical integrated circuit.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.11
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• pp.2162-2167
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• 2009

A Low cost and variable speed brushless motor drive system with single switch per phase is presented. The motor drive is realized with a novel two-phase flux-reversal-free switched reluctance motor and a split AC two switch converter. The strategy of the controller and the converter for its realization are described. Comparisons between a split AC converter, asymmetric converter, split DC converter, single controllable switch converter, and N+1 converter are performed for its device rating, cost, switching losses and conduction losses, and converter efficiency. The split AC converter is analyzed and simulated to verify the characteristics of the converter circuitry and control feasibility and the simulation results are presented. The efficiency with various loads is numerically estimated and experimentally compared from viewpoint of subsystem and system in details. The focus of this paper is to compare the presented motor drive system to the asymmetric converter system throughout experiments and demonstrate single switch per phase converter having comparable efficiency as the asymmetric converter system.