• The Transactions of the Korean Institute of Electrical Engineers D
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• v.50 no.2
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• pp.65-71
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• 2001

The step response of the Manabe standard form[2] has little overshoot and show almost same waveforms regardless of the order of the characteristic polynomials. In some situations it is difficult to control the rise time and settling time simultaneously of the step response of the Manabe standard form To control its rise time and settling time efficiently, We develop the Manabe standard form: We try to find out the SRFS(Slow Rise time & Fast Setting time) form which has the slower rise time and faster settling time than those fo the Manabe standard form. We also consider the other three forms: FRSS(Fast Rise time & Slow Settling time), SRFS(Slow Rise time & Fast Settling time) and SRSS(Slow Rise time & Slow Settling time) forms. In this paper, by using the evolutionary strategy, we obtain all the coefficient of the four forms we mention above. Finally, we design a controller for a given plant so that the overall system has the performance that the rise time is faster, the settling time is faster than those of the Manabe standard form.

• 제어로봇시스템학회:학술대회논문집
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• 1999.10a
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• pp.116-120
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• 1999

The step response of the Manabe standard form[1］has little overshoot and shows almost same waveforms regardless of the order of the characteristic polynomials. In some situations it is difficult to control the rise time and settling time simultaneously of the step response of the Manabe standard form. To control its rise time and settling time efficiently, we develop the generalization of the Manabe standard form: we try to find out the SRFS(Slow Rise time & Fast Settling time) form which has the slower rise time and faster settling time than those of the Manabe standard form. we also consider the other three forms: FRSS(Fast Rise time & Slow Settling time), SRFS(Slow Rise time ＆ Fast Settling time) and SRSS(Slow Rise time & Slow Settling time) forms. In this paper, by using the genetic algorithm, we obtain all the coefficient of the four forms we mention above. Finally, we design a controller for a given plant so that the overall system has the performance that the rise time is faster, the settling time is slower than those of the Manabe standard form.

• Journal of the Korean Society of Safety
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• v.32 no.2
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• pp.46-51
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• 2017

This paper presents classification of domestic fire detector using response time index. Response time is measured using fire detector distributed in Korea, and the response time index is estimated. Plunge test prescribed by FM is conducted to measure response time of fire detector. The detector used to test is fixed temperature type(thermistor and bimetal type) and rate of rise temperature type(thermistor and pneumatic type). The nominal operation temperature of fixed temperature type detector is $70^{\circ}C$ and rate of rise temperature is $15^{\circ}C/min$. The fixed temperature type is measured 7 products, and the rate of rise temperature type is measured 5 products. The results show that in case of fixed temperature type(thermistor) is classified "Quick" or "Standard" and fixed temperature type(bimetal) is not classified. The rate of rise temperature type(thermistor) is classified "Fast" or "Ultra Fast" and the rate of rise temperature type(pneumatic) is classified "Very Fast" or "Ultra Fast". The pneumatic type shows more fast response than thermistor type. Also these results indicate the fixed temperature type(bimetal) is not suitable for early stage fire detection.

• The Transactions of the Korean Institute of Power Electronics
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• v.26 no.1
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• pp.25-31
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• 2021

This paper describes the design of a power cell-based pulsed power modulator with fast rise times. The pulse-generating section of the pulse power modulator is a series stack of power cells. Each power cell is composed of a storage capacitor, a pulse switch, and a bypass diode. When the pulse switches are turned on, the capacitors are connected in series and the sum of voltages is applied to the load. For output pulses with fast rise times, an IGBT with fast turn-on characteristics is adopted as a pulse switch and the optimized gate driving method is used. Pspice simulation is performed to account for the gate driving method. A 10 kV, 12-power cell-based pulsed power modulator is tested under resistive load and plasma reactor load. The rise times of output pulses less than 20 ns are confirmed, showing that the pulsed power modulator can be effectively applied to pulsed power applications with fast rise times.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.2
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• pp.72-78
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• 2001

A compact size high voltage pulse generator with nanosecond rise time has been designed and investigated experimentally. The inductance of a pulse generator can be reduced by fixing the Marx generator and pulse forming network components into a single cylindrical unit. As a result, nanosecond rise time about $8{\sim}10[ns]$ and pulse width of several hundred [ns] can be obtained from a modified Marx pulse generator. And parametric studies showed that the rise time of the output pulse was depended little on the change of the load resistance and the charging capacitance while, the pulse width of the output pulse was depended greatly upon the change of the load resistance and the charging capacitance. The theoretical showed the possibility to design the laboratory-size pulse generator very fast rising time and a proper pulse width by minimizing stray inductance and varying resistance and capacitance.

• Proceedings of the KIEE Conference
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• 2008.10a
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• pp.89-90
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• 2008

Pulsed power technologies in variable fields require the pulsed high power sources. We fabricated the pulsed power generator, named EMD Pulse Generator(EPG), by using Marx circuit with 200 kV high, 50 ns fast rise time. In this paper, we described about the performances.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.6
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• pp.472-477
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• 2013

This paper carried out the comparative analysis on ground impedance of a carbon block and a copper rod. Two types of grounding electrode were compared ; a carbon block (L : 1 m, ${\Phi}$ : 245 mm) buried at a depth of 0.8 m and a three-linked copper rod (L : 1 m, ${\Phi}$ : 10 mm) of equilateral triangles with 1 m spacing. Ground impedance depending on applied current source was evaluated by the application of a sine wave current with 60 Hz ~ 3.5 MHz, a fast-rise pulse with rising time of 200 ns, a standard lightning impulse of $8/20{\mu}s$ and a 600 Hz square wave. Ground impedance for both electrodes were almost the same value below 100 kHz, and increased rapidly afterwards. The maximum ground impedance appeared $400{\Omega}$ at around 1.5 MHz. Ground impedance of the carbon block was lower at the square wave and was higher at fast-rise pulse than that of the copper rod. Also, ground impedance as ages showed no difference for the last 8 months. From the results, it is likely that ground performance for both electrodes shows no difference against commercial frequency and lightning impulse current, while the copper rod shows better performance against a fast-rise pulse with rise-time of a few hundred ns.

• Journal of the Korean Institute of Telematics and Electronics
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• v.11 no.3
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• pp.1-14
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• 1974

The gain stability of the nuclear pulse linear amplifiers with feedback for such a fast pulse input as the step voltage or the nuclear radiation detector pulse is analysed in detail. The expression is derived which describes the waveform at the anode circuit of the photomultiplier tube which is a part of the nuclear radiation detector. It is analysed and compared when the feedback amplifier has one and two time-constants. When these fast input pulse voltages are applied to the feedback amplifier, the effects of feedback in linearity and stability of the output voltage appear only after two or three rise-times of the amplifier, And it is proved that in order to reduce this limitation, the rise time of the feedback amplifier shou1d be less than the input pulse width. It is also shown that the above theory can be applied directly to the voltage-shunt feedback amplifier stages designed as the basic amplifier of the linear amplifier, and that the gain stability is more improved for the smaller input impedance of this amplifier stage.

• Nuclear Engineering and Technology
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• v.56 no.4
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• pp.1532-1537
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• 2024

Time-of-flight (TOF) PET detectors with fast-rise-time scintillators and fast-single photon time resolution silicon photomultiplier (SiPM) have been developed to improve the coincidence timing resolution (CTR) to sub-100 ps. The CTR can be further improved with an optimal bandwidth and minimized electronic noise in the readout circuit and this helps reduce the distortion of the fast signals generated from the TOF-PET detector. The purpose of this study was to develop an ultra-high frequency and fully-differential (UF-FD) readout circuit that minimizes distortion in the fast signals produced using TOF-PET detectors, and suppresses the impact of the electronic noise generated from the detector and front-end readout circuits. The proposed UF-FD readout circuit is composed of two differential amplifiers (time) and a current feedback operational amplifier (energy). The ultra-high frequency differential (7 GHz) amplifiers can reduce the common ground noise in the fully-differential mode and minimize the distortion in the fast signal. The CTR and energy resolution were measured to evaluate the performance of the UF-FD readout circuit. These results were compared with those obtained from a high-frequency and single ended readout circuit. The experiment results indicated that the UF-FD readout circuit proposed in this study could substantially improve the best achievable CTR of TOF-PET detectors.

• Journal of the Korean Institute of Telematics and Electronics
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• v.10 no.5
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• pp.7-15
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• 1973

The gain stability of the nuclear pulse ampifiers with negative feedback for such a fast pulse input as the step voltge or the nuclear radiation detector pulse is analyzed in detail and the experimental results are given. It is shown that a few risetime should elapse to get the full effect of the negative feedback upon the liearity and the stability of the amplifiers for the fast pulse input, and to reduce this limitation the risetime of the negative feedback amplifier must be designed to be short compared with the width of the input pulse.