• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.344-347
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• 2001

A high frequency resonant inverter consisting of three unit half-bridge serial resonant inverter used as power source of induction heating at high frequency is presented in this paper. As a output power control strategy, tine-sharing gate control method is applied. The analysis of the proposed circuit is generally described by using the normalized parameters. Also, according to the calculated characteristics value, a method of the circuit design and operating characteristics of the inverter is proposed. This paper proves the validity of theoretical analysis through the experiment. This proposed inverter show that it can be practically used in future as power source system for induction heating application, DC-DC converter etc.

• Journal of the Semiconductor & Display Technology
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• v.23 no.2
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• pp.100-106
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• 2024

To generate the plasma required in dry cleaning processes, the plasma chamber must be supplied with a high-quality AC voltage with a voltage of more than 1 kV and a frequency of 400 kHz. In the existing research, many methods to supply high power have been studied, but how to improve the quality of the power for high-quality plasma has been relatively little studied. In this paper, we propose a study to improve the quality of RF power circuit for high-quality plasma generation in dry cleaning method. Existing methods in the environment of full-bridge-based RF power circuits must perform PWM duty control in the light load region. This causes distortions in the waveform, resulting in poor power quality, which directly leads to poor plasma quality. To solve these problems, a half-bridge switching method is proposed and the improvement in waveform quality is verified. To verify the feasibility of the design and control algorithm proposed in this paper, an RF power circuit prototype is fabricated and the proposed design and control method is verified through simulation and actual experiments under dummy load.

• Journal of Power Electronics
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• v.10 no.1
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• pp.14-20
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• 2010

In this paper, a tightly regulated triple output asymmetrical half bridge flyback (ASHF) converter is proposed. In order to regulate all output voltages, pulse frequency modulation (PFM), pulse width modulation (PWM) and phase delay (PD) are used simultaneously. In comparison with the conventional PWM-PD method, the interactions among the control variables are minimized and the operating range is increased. By the utilization of a multi winding transformer, the auxiliary transformer and the blocking capacitor are eliminated and the size and cost of the proposed converter is reduced. The operation principle of the converter is explained and the modes of operation are investigated. Based on the results, the steady state characteristics of the converter are explored. A 24V/10A, 12V/5A, 5V/10A hardware prototype is built and tested to verify the analysis results and the voltage regulation of the triple outputs of the proposed converter.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.1939-1944
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• 2000

Different test methods were used to measure and compare the loss factor of a steel beam. They are free vibration logarithmic decay method, half-power bandwidth method using narrow-band analysis, wide-band analysis method with inverse FFT. In these tests, specimens are clamped at one end. Free vibration method and half-power bandwidth method gave good results. Effect of vibration pick-ups were tested. We also tried center excitation method but could not obtain loss factor.

• The Transactions of the Korean Institute of Power Electronics
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• v.22 no.5
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• pp.457-462
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• 2017

This paper proposes a digital power control of the LLC resonant half-bridge inverter for high power microwave oven application. Conventional half-bridge inverter for driving a microwave oven uses a hardware-based power control method which varies the frequency according to the AC source voltage. In this case, it is difficult to control the output power according to the variation of the load status of magnetron. The proposed power control consists of an instantaneous current generator and a current controller. Instantaneous current generator makes an instantaneous current reference from power command using input voltage information. Current controller controls input current which has an information of status of magnetron. The proposed power control does not require any compensation algorithm for the change of the load status of the magnetron and change of input voltage. The validity of the proposed method for the control of the change of input voltage and frequency is verified by both simulation and experiment.

• Journal of Power Electronics
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• v.15 no.6
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• pp.1593-1600
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• 2015

This paper proposes a novel compensation algorithm of current offset error for single-phase linear compressor in home appliances. In a half-bridge inverter, current offset error may cause unbalanced DC-link voltage when the DC-link is comprised of two serially connected capacitors. To compensate the current measurement error, the synchronous reference frame transformation is used for detecting the measurement error. When an offset error occurs in the output current of the half-bridge inverter, the d-axis current has a ripple with frequency equal to the fundamental frequency. With the use of a proportional-resonant controller, the ripple component can be removed, and offset error can be compensated. The proposed compensation method can easily be implemented without much computation and additional hardware circuit. The validity of the proposed algorithm is verified through experimental results.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.30 no.1
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• pp.79-86
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• 2016

In this paper, we propose a current-driven synchronous rectifier driver circuit for LLC resonant half-bridge converters. The proposed driver circuit detects a relatively low current in the primary side of the transformer although a large current is flowing in the secondary side. Due to this feature, the driver circuit has a simple circuit structure and stabilizes the switching operation with a logic-level switching voltages for the synchronous rectifier. The operation and performance of the proposed driver circuit are confirmed with a prototype of 1kW class LLC resonant half-bridge converter. The experimental results proved that the proposed synchronous rectifier driver method improves the power conversion efficiency by around 1% and reduces the internal power loss by 17W.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.11a
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• pp.44-47
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• 2011

In this paper, we propose context-aware based on Low Power Sensing Algorithm. The proposed sensing algorithm reduces power consumptions using low-power sensing algorithms and low-power sensing protocols. Experimental results show that the average power consumption of the proposed method is up to half consumption that of the conventional method.

• Journal of Sensor Science and Technology
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• v.26 no.6
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• pp.408-413
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• 2017

In this paper, we newly developed a byte-inverted transmission method for flicker-free visible light communication (VLC). The VLC transmitter sends original data in the former half period of the clock, and inverted data and in the latter half period of the clock. The VLC receiver receives the original data in the in the former half period of the clock. In this system, we used 480Hz clock that was generated from the 60Hz power line. The average optical power of the LED array in the transmitter is constant, thus flicker-free, in the observation time longer than the period of the clock that is about 2ms. This period is shorter than the maximum flickering time period (MFTP) of 5ms that is generally considered to be safe. This configuration is very useful in constructing indoor wireless sensor networks using LED light because it is flicker-free and does not require additional transmission channel for clock transmission.

• Proceedings of the KIPE Conference
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• 2004.11a
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• pp.49-53
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• 2004

High density power supply technology has been researched over the last few years. In this paper, integrated LLCT(Inductor-Inductor-Capacitor-Transformer) structure is described for use in the half-bridge series resonant converter. The structure is analysed by means of FEMM(Finite Element Method Magnetics) and the experimental results of an U structure for a 300W converter we presented.