• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.3
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• pp.165-168
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• 2000

Improvement on the switching characteristic of IGBT by means of the uniform and local lifetime control is studied numerically using two-dimensional simulator, MEDICI. In the case of uniform lifetime control, the on-state and switching characteristics are simulated as a function of lifetime, and compared with the experimental results reported, which allows a relationship between dose of electron irradiation and controlled lifetime. In the case of local lifetime control, simulations are carried out by varying the position, width, and lifetime of the locally controlled region, and the results are compared with the characteristics for the case of the uniform lifetime control. The turn-off time of the device with an optimized locally controlled region is found to decrease from about $4.5\mus$ to 0.11$mutextrm{s}$ while the forward voltage drop increases from 1.37V to 2.61V in comparison with that for the uniform lifetime control.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.30B no.10
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• pp.27-34
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• 1993

In this paper, a driver system is designed and implemented to achieve 4-level gray scale CH TFEL(Thin Film ElectroLuminescent) flat panel display. To implement the driver system, commercial EL driver IC chips are used to apply high voltage pulses to the EL panel and a high voltage switching circuit is designed for the EL driver IC. A new method of reducing storage delay time of transistor is proposed to obtain a reliable switching circuit. The controller for EL driver and switching circuit is also designed. The designed driving scheme applicable to EL display with 4-level gray scale is based on the linear characteristics of brightness vs. frequency of AC TFEL. By experiment, it has been shown that the brightness of AC TEFL display with the implemented driving system is controlled by the level of gray scale.

• Proceedings of the IEEK Conference
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• 2004.06b
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• pp.439-442
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• 2004

Timing delays due to VLSI circuit interconnects strongly depend on neighbor line switching patterns as well as input transition time. Considering both the input transition and input switching pattern, a new analytical timing delay model is developed by using the decoupling technique of transfer multi-coupled lines into an effective single line. The analytical timing delay model can determine the timing delay of multi-coupled lines accurately as well as rapidly. It is verified by using DSM-Technology ($0.1{\mu}m$ /low-k copper-based process) that the model has excellent agreement with the results of SPICE simulation.

• Proceedings of the KIEE Conference
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• 1991.11a
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• pp.231-233
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• 1991

This paper discribes a study on the switching character of MOS-GTO and the design of gate drive circuit. Chopping power supply converter, synchronious and asyncronious motor speed adjustment, inverter, etc., needs low drive energy "high frequency" switches. To fulfill these need, switches must have rapid switching time and insulated gate control. MOS-GTO structure is well suited to these constraints. The power switch is serial installation of a GTO thyrister and a MOS Transistor. The gate of the GTO is linked to positive pole of the cascode structure via a MOS high voltage transistor and ground via a transient absorber diode. This high performance MOS-GTO assembly considerably increases the strength which facilitate the drive of GTO thyristers.

• Proceedings of the KIEE Conference
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• 1990.11a
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• pp.432-435
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• 1990

Neural networks are a class of systems that have many simple processors (neurons) which are highly interconnected. The function of each neuron is simple, and the behavior is determined predominately by the set of interconnections. Thus, a neural network is a special form of parallel computer. Although major impetus for using neural networks is that they may be able to "learn" the solution to the problem that they are to solve, we argue that another, perhaps even stronger, impetus is that they provide a framework for designing massively parallel machines. The highly interconnected architecture of switching networks suggests similarities to neural networks. Here, we present switching applications in which neural networks can solve the problems efficiently. We also show that a computational advantage can be gained by using nonuniform time delays in the network.

• Proceedings of the KIEE Conference
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• 2006.04b
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• pp.57-61
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• 2006

In the single-phase switched reluctance motor (SRM) drive, the required DC source is generally supplied by the circuit consisting of bridge rectifier and large filter capacitor connected with DC line terminal. Due to the large capacity of the capacitor, the charged time of capacitor is very short from the AC source. Lead to the bridge rectifiers draws pulsating current from the AC source side, which results in reduction of power factor and low system efficiency. Therefore a novel single-phase SRM drive system is presented in this paper, which includes drive circuit realizing reduction of torque ripple and improvement of power factor with a novel switching topology. The proposed drive circuit consists of one switching part and diode, which can separate the output of AC/DC rectifier from the large capacitor and supply power to SRM alternately, in order to realize the torque ripple reduction and power factor improvement through the switching scheme. In addition, the validity of the proposed method is tested by some simulations and experiments.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.151-154
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• 2001

In this paper, a two-level switching algorithm of the deadbeat to control PWM inverter is proposed. A modified algorithm of the deadbeat is suitable for the UPS system. Two levels in the pulse pattern are used. This scheme allows the use of higher switching frequency for a given computation time delay, which results in lower total harmonic distortion at the output. The proposed control scheme is implemented using TMS320F240 DSP chip for controlling on inverter.

• Proceedings of the KIEE Conference
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• 2003.04a
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• pp.53-55
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• 2003

It is indispensable to compensate the switching characteristic variation of circuit breakers in use due to the change of operating conditions in order to get the reliable performance of controlled switching. In this paper the compensation measures against main factors such as temperature, control voltage, idle time and operating number are described. And the performance of the proposed measure is verified through the experimental results.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.482-484
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• 1994

In this paper, to realize high speed position control of LDM (Linear DC Motor), the minimum time control method is applied. But, In this control method, calculation of non-linear function is required Therefore, in order to avoid this complex calculation, optimum switching of the Bang-Bang control is done on parabola type switching function established in the plane of phase. But, the sliding mode is occurred due to the modeling error of LDM and the variation of parameters. Thereby, the optimum 'control is not realized. In order to realize optimum control, the algorithm to modify switching function is proposed

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.12
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• pp.9-16
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• 2010

In this paper, we have proposed a new dimmable magnetic ballast for HID(High Intensity Discharge) lamps consisted of AC switches to variate inductance value by using Silicon Controlled Rectifiers and the isolated zero current detector on inductor. Conventional dimming ballast has used relays or Solid State Relays in AC switches. However, a relay is difficult to zero current switching, because it has long operating time(10[ms]), and price competitiveness of SSR is very low. The proposed AC switches are suitable to switch at zero inductor current and it is accurately detected by using a opto-coupler. SCR is cheaper than SSR, and it is suitable to switch at zero inductor current because SCR is automatically turned off under holding current at no gate signal. Operating principles, simulation results and experimental results of the proposed ballast are described.