• Journal of Electrical Engineering and Technology
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• 제8권1호
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• pp.150-155
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• 2013

A high voltage and nanosecond Blumlein pulse generator has been developed to produce an output pulse whose voltage level is greater than 250 kV and pulse duration 5 ns. The generator consists of various components such as a charging circuit, a pulse transformer, and a spark gap switch. As a heart of the generator, a Blumlein pulse forming line has been constructed in the cylindrical form using three cylindrical aluminum electrodes that are placed concentrically. Unlike the ideal Blumlein line, the output pulse of an actual Blumlein line may be affected by stray inductances and capacitances of switching and charging components, thereby degrading the performance of the generator. In this paper, PSPICE simulations have been performed to examine effects of stray inductances and capacitances on waveforms of output pulses. Simulation results show that the pulse waveform is significantly distorted mainly by the stray inductance of the spark gap switch.

• Journal of Magnetics
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• 제16권3호
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• pp.234-239
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• 2011

Transcranial magnetic stimulation utilizes the method of controlling applied time and changing pulse by output pulse through power density control for diagnosis purposes. Transcranial magnetic stimulation can also be used in cases where diagnosis and treatment are difficult since output pulse shape can be changed. As intensity, pulse range, and pulse shape of the stimulation pulse must be changed according to lesion, the existing sine wave-shaped stimulation treatment pulse poses limitations in achieving various treatments and diagnosis. This study actualized a new method of transcranial magnetic stimulation that applies a 3 Stage 2 Switch( power semiconductor 2EA) for controlling pulse repetition rate by achieving numerous switching control of stimulation coil. Intensity, pulse range, and pulse shape of output can be freely changed to transform various treatment pulses in order to overcome limitations in stimulation treatment presented by the previous sine wave pulse shape. The method of freely changing pulse range by using 3 Stage 2 Switch discharge method is proposed. Pulse shape, composed of various pulse ranges, was created by grafting PFN (Pulsed Forming Network) through AVR AT80S8535 one-chip microprocessor technology, and application in transcranial magnetic stimulation was achieved to study the output characteristics of stimulation treatment pulse according to delaying time of the trigger signal applied in section switch.

• 한국항공우주학회지
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• 제31권5호
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• pp.63-71
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• 2003

본 논문에서는 몸체진동형 링레이저 자이로에서 몸체진동을 검출하기 위한 각속도 센서 출력을 V-F 변환하여 링레이저 출력에서 몸체진동에 의한 출력을 제거하는 dither-stripping 방법에 대하여 논의하였다. Dither-stripping에서는 V-F 출력펄스와 링레이저 출력펄스간의 환산계수를 산출하는 방법과 V-F 출력펄스의 offset를 보정해주는 방법이 중요하다. 각속도 센서의 출력을 V-F 변환하여 dither-stripping하는 경우에는 offset을 보정하는 과정에서 몸체진동의 진폭잡음에 의한 자이로 출력의 오차가 크게 발생한다. 우리는 V-F 출력펄스를 미분하여 offset을 제거하는 방법을 고안하였다. 이를 위해서는 각속도 센서의 출력을 90deg 위상 이동시켜서 각도신호를 만들고 V-F 변환해야 하며 링레이저 출력의 위상도 샘플링의 반주기만큼 이동시켜야 한다. 그리고 두 펄스간의 환산계수는 분산을 이용하여 산출하였다. 이러한 각도신호 미분방식의 dither-stripping에 의하여 개선된 결과를 얻을 수 있었다.

• 조명전기설비학회논문지
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• 제26권12호
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• pp.80-86
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• 2012

The high-voltage pulse generator is consist of transformers of fundamental wave and harmonic waves, and shunt capacitances. The pulse has the fundamental wave and the harmonic waves that have been increased as a series circuit by the transformers to make high voltage pulse. This paper shows the high-voltage pulse generator simulation using a circuit program with experiment data. In the equivalent circuit, magnetized inductances and loss resistances which affect output voltage, have been obtained. The output capacitor circuits have characteristics of band pass. The output voltages of the pulse width 50% and 25%(PWM) were obtained. The output of the high-voltage pulse generator is 2.5kHz, 1.8kV.

• 전기학회논문지
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• 제56권1호
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• pp.88-99
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• 2007

In this paper, a novel new pulse power generator based on IGBT stacks is proposed for pulse power application. Because it can generate up to 60kV pulse output voltage without any step- up transformer or pulse forming network, it has advantages of fast rising time, easiness of pulse width variation and rectangular pulse shape. Proposed scheme consists of series connected 9 power stages to generate maximum 60kV output pulse and one series resonant power inverter to charge DC capacitor voltage. Each power stages are configured as 8 series connected power cells and each power cell generates up to 850VDC pulse. Finally pulse output voltage is applied using total 72 series connected IGBTs. To reduce component for gate power supply, a simple and robust gate drive circuit is proposed. For gating signal synchronization, full bridge invertor and pulse transformer generates on-off signals of IGBT gating with gate power simultaneously and it has very good characteristics of short circuit protection.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 Proceedings of the Korea Automatic Control Conference, 11th (KACC); Pohang, Korea; 24-26 Oct. 1996
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• pp.255-258
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• 1996

This paper describes a DC voltage controller for the DC power supply which is constructed using the full-bridged MOS-FET DC-to-RF power inverter and rectifier. The full-bridged MOS-FET DC-to-RF inverter consisting of four MOSFET arrays and an output power transformer has a control function which is able to control the RF output power when the widths of the pulse voltages which are fed to four MOS-FET arrays of the fall-bridged inverter are changed using the pulse width control circuit. The power conversion efficiency of the full-bridged MOS-FET DC-to-RF power inverter was approximately 85 % when the duty cycles of the pulse voltages were changed from 30 % to 50 %. The RF output voltage from the full-bridged MOS-FET DC-to-RF inverter is fed to the rectifier circuit through the output transformer. The rectifier circuit consists of GaAs schottky diodes and filters, each of which is made of a coil and capacitors. The power conversion efficiency of the rectifier circuit was over 80 % when the duty cycles of the pulse voltages were changed from 30 % to 50 %. The output voltage of the rectifier circuit was changed from 34.7V to 37.6 V when the duty cycles of the pulse voltages were changed from 30 % to 50 %.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2007년도 추계학술대회 논문집
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• pp.43-46
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• 2007

In this paper, a novel new pulse power generator based on IGBT stacks is proposed for pulse power application. Proposed scheme consists of series connected 9 power stages to generate maximum 60kV output pulse and one series resonant power inverter to charge DC capacitor voltage. Each power stages are configured as 8 series connected power cells and each power cell generates up to 850VDC pulse. Finally pulse output voltage is applied using total 72 series connected IGBTs. The synchronization of gating signal is important for series operation of IGBTs. For gating signal synchronization, full bridge inverter and pulse transformer generates on-off signals of IGBT gating and specially designed gate power circuit was used. Proposed scheme has lots of advantages such as long lifecyle, compact size, flat topped pulse forming, small weight, protection for arc, high efficiency and flexibility to generate various kinds of pulse output.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2000년도 전력전자학술대회 논문집
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• pp.294-298
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• 2000

A new pulse multiplication technique based on 6-pulse thyristor converters is proposed in this paper. With the proposed technique 12-pulse 18-pulse and 24-pulse operations have been obtained both on the input current and on the output voltage. A control strategy over the whole range of phase angle is provided along with sophisticated input current and output voltage analysis. Experimental results from a laboratory prototype verify the proposed theory.

• 대한전기학회논문지
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• 제41권1호
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• pp.24-31
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• 1992

A 24 pulse current source inverter for reducing the harmonics in output currents is presented in this paper. The proposed system operates a 24 pulse inverter by adding only tap changing circuit which consists of several taps and static switching elements to the 12 pulse inverter, which is the double connected 3 phase 6 pulse inverter with an auto transfomer. Also to optimize the effectiveness of the harmonic reduction, the optimum turn ratio and tap changing control angle of auto transfomer are decided by digital simulation and its validity is verified with experiment. And under the optimum condition, it is clarified that the harmonics components involved in the output current of the proposed inverter are nearly equal to those of the conventional 24 pulse inverter.

• Journal of the Optical Society of Korea
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• 제7권4호
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• pp.258-263
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• 2003

Simple algebraic expressions are derived to approximate the optimal input RMS pulse width and the resulting output RMS pulse width in single-mode fibers. The results are compared with the previously published methods and with numerical results by the split-step Fourier method. In addition, for a transform-limited Gaussian input pulse, it is shown that there is no optimum input pulse width to minimize the output spectrum width. Finally, with fiber nonlinearity, it is shown mathematically that there is not an optimum input pulse width to minimize the product,${\sigma}_t{\sigma}_{\omega}$, which is inversely proportional to the transmission capacity of WDM systems.