• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1577-1579
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• 1994

200-MW pulse modulators(total 11units) for the PLS linac employ the SCR phase control circuit. It controls 3-phase AC line voltage for the high-voltage DC power supply (DCPS, maximum of 25kVDC, 4.2A) which charges the pulse forming network(PFN). The PFN delivers 400kV, 500A, ESW $7.5{\mu}s$ pulse power to the 80-MW klystron amplifier tube. The SCR regulates 3-phase AC power and feeds to the high voltage transformer. Two different types of the transformer configurations namely ${\Delta}-{\Delta}$ and ${\Delta}-Y$, are alternatively installed to 11 modulator units for the suppression of harmonic noises. RC filters and reactors are also installed. Currently, approximately 110-kW of average AC power per unit is consumed at the normal operation level of the modulator with 30pps. This paper presents the operational characteristics of the high power pulse modulator, especially the experimental results of the AC line harmonic components generated by the operation of the high power pulse modulator to suppress the switching noises from the SCR and rectifying diode arrays.

• Proceedings of the KIPE Conference
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• 2004.07b
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• pp.822-825
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• 2004

This paper describes the improvement of performance of power supply for ship's emergency lighting system(SELS). Proposed system is composed of power factor correction (PFC) circuit, emergency power supply system (EPSS), half bridge(HB) inverter, fluorescent lamp(FL) starting circuit and microprocessor control system. Experimental works using proposed system confirm that speedy and stable power to be supplied when main power source cut-off, compared with conventional relay type, and control power factor up to $97.5[\%]$ and input power up to $35.0[\%]$ by adjusting of pulse frequency of the HB inverter.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.4
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• pp.440-446
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• 2011

In this paper, a X-band 50 W pulsed solid state power amplifier(SSPA) is designed and fabricated for radar systems. The SSPA consists of a driver amplifier, a high power amplifier, and a pulse modulator. The high power stage employes four 25 W GaAs FET to deliver 50 W at X-band. To meet the stringent target specification for the SSPA, we used a new hybrid pulse switching method, which combine the advantage of pulse modulation and bias switching method. The fabricated SSPA shows a power gain of 44.2 dB, an output power of 50 W over a 1.12 GHz bandwidth. Also, pulse droop < 1 dB meet the design goals and a rise/fall time is less than 12.45 ns. Fabricated X-band pulsed SSPA size is compact with overall size of $150{\times}105{\times}30\;mm^3$.

• Proceedings of the KIEE Conference
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• 1998.07e
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• pp.1755-1757
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• 1998

Pulse transformers have been developed to apply for pulsed power technology as an alternative of a Marx generator. To obtain repetitive pulsed power generation, it is necessary to observe the rising time of output of pulse transformer. In this paper, using the equivalent circuit, The rising wave of output of pulse transformer is simulated for various input wave by using the Electromagnetic transient program(EMTP).

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.507-510
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• 2005

High voltage pulse power supply using Marx generator and solid-state switches is proposed in this study. The Marx generator is composed of 12 stages and each stage is made of IGBT stack, two diode stacks, and capacitor. To charge the capacitors of each stage in parallel, inductive charging method is used and this method results in high efficiency and high repetition rates. It can generate the pulse voltage with the following parameters: Voltage: up to 120kv Rising time: sub ${\mu}S$ Pulse width: up to $10{\mu}S$, Pulse repetition rate: 1000pps The proposed pulsed power generator uses IGBT stack with a simple driver and has modular design. So this system structure gives compactness and easiness to implement total system. Some experimental results are included to verify the system performances in this paper.

• Journal of the Korea Computer Industry Society
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• v.2 no.8
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• pp.1055-1062
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• 2001

Study, it is the purpose to develope a cheap and compact pulsed $CO_2$ laser with pulse repetition rate range of 1 KHz. We used a IGBT switched power supply as a power supply, which is cheap and simple comparing to others. PIC one-chip microprocessor was used for precise control of a laser power supply on the control part. And the laser cavity was fabricated as an axial and water cooled type. The laser performance characteristics as various parameters, such as pulse repetition rate, gas pressure, and gas mixture rate have been investigated. The experiment was done under the condition of total pressure of $CO_2$： $N_2$：He ＝ 1：3：10, 1：1.5：5, 1：9：15 from 6 Torr to 15 Torr and pulse repetition rate from 100 Hz to 900 Hz. As a result, the maximum average outpu was about 20.5 W at the total pressure of 15 Torr, the gas mixture $CO_2$：$N_2$：He ＝ 1：9：15 and the pulse repetition rate of 700 Hz.

• Proceedings of the KIEE Conference
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• 1999.11d
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• pp.1072-1074
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• 1999

In this study, it is the purpose to develope a cheap and compact pulsed $CO_2$ laser with pulse repetition rate range of 1 kHz. We used a IGBT switched power supply as a power supply, which is cheap and simple comparing to others. PIC one-chip microprocessor was used for precise control of a laser power supply on the control part. And the laser cavity was fabricated as an axial and water cooled type. The laser performance characteristics as various parameters, such as pulse repetition rate gas pressure, and gas mixture rate have been investigated. The experiment was done under the condition of total pressure of $CO_2:N_2$:He = 1.3:10, 1:1.5:5 1:9:15 from 6 Torr to 15 Torr and pulse repetition rate from 100 Hz to 900 Hz. As a result, the maximum average output was about 20.5 W at the total pressure of 15 Torr, the gas mixture $CO_2:N_2$:He = 1:9:15 and the pulse repetition rate of 700 Hz.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.11B no.4
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• pp.180-184
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• 2001

The high operation frequency mainly reduces transformer volume in the power supply. A high frequency and high voltage pulse transformer is designed, fabricated, and tested. Switching frequency of the transformer is 100 kHz. Input and output voltages of the transformer are 250 V and 4 kV, respectively. Normal operation power of the transformer is 3 kW. Maximum volume of the transformer is 400 $cm^3$. The power density is thus 7.5 W/$cm^3$. The transformer will be installed in a metal box that has nominal operation temperature of 85 degree centigrade. The transformer and other high voltage components in the box will be molded with Silicon RTV(Room Temperature Vulcaniza) that has a very low thermal conductivity. Procedure of design and test results are discussed. Analytical as well as experimental results of varous paramters such as transformer loss, leakage inductance, distributed capacitance are also discussed. In addition, thermal analysis results from ANSYS code for three different operation conditions are discussed.

• The Transactions of the Korean Institute of Power Electronics
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• v.7 no.4
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• pp.332-338
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• 2002

High current coil power supply for superconductivity coil of tokamak requires fast dynamics performance of di/dt and smooth change over of current direction. To meet the specification high performance DSP-based controller Is designed for 12-pulse thyristor dual converter with interphase transformer(IPT). Not only the total current of Y and $\Delta$ converter units but also the difference for those should be regulated fast and accurately. Proportional and integral controller is designed for current difference control and the controller output is compensated to $\Delta$ converter. The source voltage phase angle detection and gate pulse generation algorithm are implemented in software for higher reliability of current control. The current error Is reduced by selection of appropriate initial gating angle during the transient of change over of current direction between thyristor converters.

• Proceedings of the KIEE Conference
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• 1999.11d
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• pp.1060-1062
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• 1999

Pulsed Nd:YAG laser is used widely for materials processing and instrumentation. It is very important to control the laser energy density in materials processing by a pulsed Nd:YAG laser. A pulse repetition rate and a pulse width are regarded as the most dominant factors to control the energy density of laser beam. In this study, the alternating charge-discharge system was designed to adjust a pulse repetition rate. And the parallel mesh is added to increase laser output power. This system is controlled by one chip microprocessor and allows to replace an expensive condenser for high frequency to a cheap condenser for low frequency. In addition, we have investigated the current pulse shape of flashlamp and the operating characteristics of a pulsed Nd:YAG laser. As a result, it is found that the laser output of the power supply using the parallel mesh and the alternating charge-discharge system is not less than that of typical power supply. As the pulse repetition rate rises from 10pps to 110pps by the step of 20pps at 1000V and 1200V, it is found that the laser efficiency decreases but the laser output power increases about 5W at each step.