• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.59 no.2
• /
• pp.338-343
• /
• 2010

Low cost motor drives are being sought for high volume energy efficient home appliances. Key to the realization of such low cost motor drives is to reduce the power electronic converter in terms of its components, particularly the active devices, finding the motor with least complexity for manufacturing and a controller that could extract the desired performance from the machine and converter combination. These and other factors such as self-starting, speed control over a wide range and most of all the crowning aspect of a four quadrant operation with bare minimum number of controllable switch (or switches) remain as formidable challenges for low cost motor drive realization. In this paper, a four quadrant switched reluctance motor (SRM) drive with only one controllable switch is realized by using a two-phase machine. The theory and operation of the proposed four-quadrant SRM drive with the proposed control algorithm for its realization are described. The motor drive is modeled, simulated and analyzed to verify its feasibility for self-starting, speed control and for four quadrant operation and the simulation results are presented. Experimental results confirm the validity of the proposed control algorithm for four quadrant control of the SRM drive. The focus of the paper is mainly directed toward the control algorithm for realizing the four-quadrant operation of the two-phase SRM drive with a single controllable switch converter.

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

• Journal of Electrical Engineering and Technology
• /
• v.10 no.1
• /
• pp.216-226
• /
• 2015

The neutral beam injection generate ultra-high temperature energy in the tokamak of nuclear fusion. The neutral beam injection make up arc power supply, filament power supply and acceleration & deceleration power supply. The arc power supply has characteristics of low voltage and high current. Arc power supply generate arc through constant output of voltage and current. So this paper proposed suitable buck converter for low voltage and high current. The proposed buck converter used parallel switch because it can be increased capacity and decrease conduction loss. When an arc generated, the neutral beam injection chamber occur high voltage. And it will break output capacitor of buck converter. Therefore the output capacitor was removed in the proposed converter. Thus the proposed converter should be designed for the characteristics of low voltage and high current. Also, the arc power supply should be guaranteed for system stability. The proposed parallel buck converter enables the system stability of the divided low output voltage and high current. The proposed converter with constant output be the most important design of the output inductor. In this paper, designed arc power supply verified operation of system and stability through simulation and prototype. After it is applied to the 288[kW] arc power supply for neutral beam injection.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.21 no.4
• /
• pp.19-27
• /
• 2007

This paper presents a novel soft-switching PWM utility frequency AC to high frequency AC power conversion circuit incorporating boost H-bridge inverter topology, which is more suitable and acceptable for cost effective consumer induction heating applications. The operating principle and the operation modes are presented using the switch mode equivalent circuits and the operating voltage and current waveforms. The performances of this high-frequency inverter using the latest IGBTs are illustrated, which includes high frequency power regulation and actual efficiency characteristics based on zero voltage soft-switching(ZVS) operation ranges, and the power dissipation as compared with those of the conventional type high frequency inverter. In addition, a dual mode control scheme of this high frequency inverter based on asymmetrical pulse width modulation(PWM) and pulse density modulation(PDM) control scheme is discussed in this paper in order to extend the soft switching operation ranges and to improve the power conversion efficiency at the low power settings. The power converter practical effectiveness is substantially proved based on experimental results from practical design example.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.37 no.6
• /
• pp.57-63
• /
• 2000

A multi-branch thermo-optic switch has a problem that driving powers in the switching states are different from each other; the power consumption for the inner output port is more than twice as large as that form the outer output port. In this pater, to solve this problem unequal width heaters and the waveguide structure with a thin overcladding layer are proposed in a four-branch thermo-optic switch. The proposed structure is fabricated with the polymer materials with high index difference, Teflon and polyimides. The fabricated device was measured at the wavelength of 1550 nm. The measured characteristics exhibit the smaller difference in the power consumption between the switching states and the driving power les than the previous four-branch thermo-optic switch with equal width heaters. As for the device performance, the crosstalk is better than - 16 dB at about 310 ~ 390 mW, the insertion loss is 4.7 dB, and the switching time is less than 1 ms.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.23 no.7
• /
• pp.20-28
• /
• 2009

This paper presents the design of zero current switching ZCS pulse frequency modulation type DC-DC converter for magnetron power supply. A magnetron serving as the microwave source in a microwave oven is driven by a switch mode power supply (SMPS). SMPSs have the advantages of improved efficiency, reduced size and weight, regulation and the ability to operate directly from the converter DC bus. The demands of the load system and the design of the power supply required to produce constant power at 4[kV]. A magnetron power supply requires the ability to limit the load current under short circuit conditions. The current source series resonant converter is a circuit configuration which can achieve this. The main features of the proposed converter are an inherent protection against a short circuit at the output, a high voltage gain and zero current switching over a large range of output power. These characteristics make it a viable choice for the implementation of a high voltage magnetron power supply.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.20 no.1
• /
• pp.51-58
• /
• 2015

In order to decrease the size of a switch mode power supply, high switching frequency can be an efficient way to reduce the size of passive components in the converter. In this paper, a 500-kHz high-frequency LLC resonant converter is proposed with an accurate design method of magnetizing inductance, as well as the relationship between the switching frequency and the size of the passive components. Simulation and experimental results are presented to verify the proposed methods and equations, including the temperature data of each passive and active device of the converter. Using those results, dominant power losses in the prototype converter under 500-kHz high-frequency operation are investigated, compared with the results from a 100-kHz converter. In addition, operating waveforms and power conversion efficiency will be shown to obtain design considerations for the high switching frequency LLC resonant converter.

• Proceedings of the KIPE Conference
• /
• 2003.07a
• /
• pp.291-293
• /
• 2003

A semiconductor switch-based fast hi-polar high voltage pulse generator is proposed in this paper The proposed pulse system is made of a thyristor based-rectifier, DC link capacitor, a push-pull resonant inverter, a high voltage transformer. secondary capacitor, a high voltage IGBT & diode stacks, and a variable capacitor. The proposed system makes hi-polar high voltage sinusoidal waveform using resonance between leakage inductance of the transformer and secondary capacitor and transfers energy to output load at maximum of the secondary capacitor voltage. Compared to previous hi-polar high voltage pulse power supply using nonlinear transmission line, the proposed pulse power system using only semiconductor switches has simple structure and gives high efficiency

• Proceedings of the KIPE Conference
• /
• 2004.07b
• /
• pp.815-818
• /
• 2004

The emerging applications such as reliable back-up power system and renewable energy call for high boost U-n converter. The conventional topologies to get high output voltage are using flyback circuit, cascade converters, and coupled inductor DC-DC converter. They have the stress and loss related to the leakage energy which results in low efficiency Tn this paper, novel high boost converter is presented. It has a structure of cascade boost converter but only one switch. Therefore, drive circuit is simple and extreme duty ratio is eliminated. To verify the proposed circuit, theoretical analysis and experimental results has been done using a prototype power supply.

• Proceedings of the KIEE Conference
• /
• 2003.07a
• /
• pp.537-539
• /
• 2003

퓨즈 부착 고압 교류부하개폐기(Alternating current switch-fuse combination)는 개폐기와 한류형 퓨즈의 조합으로서 각각의 규격(개폐기는 IEC60265-1, 한류형 퓨즈는 IEC60282-1)에 따른 개발시험을 실시 한 후 휴즈부착 고압교류 부하개폐기의 규격인 IEC62271-105에 따라 개발시험이 이루어진다. 본 논문에서는 최근에 개정된 IEC62271-105의 신구 비교, 시험종류 및 시험방법에 대해서 기술하였다.