Currently-using low-pressure lamps are usually drivel by the AC power supply. There are good and bad points according to high or low frequency in AC power driving type. For the low-pressure lamps, its efficiency increases and flicker decreases when it ignites at high frequency. So we already use the high-frequency electronic ballast of the low-pressure discharge lamps broadly. But there are EMI interference in high-frequency driving type because of giving the fluorescent lamp the high- frequency current. So recently, we have a tendency to compensate for that defects by DC driving method. As follows, we suggest pseudo DC discharging electronic bar lasts for fluorescent lamps which have the characteristics of high efficiency and no flicker by driving constant current boosted square wave.

Incandescent lamps and discharge lamps are generally used as light sources and special ballasts are needed thor stable operation of discharge lamps. In this paper, the author proposes the electronic ballast thor metal hallide lamps, experiments with high frequency square wave of frequency 22.52 KHz to avoid the acoustic resonance phenomenon and proves the usefulness of the proposed ballast. Furthermore, the author uses 220 AC voltage as a input voltage source of the proposed ballast. By examining the proposed ballast, lamp voltage of 139 V(max.) and lamp current of 1.4 A(max) can be measured. Furthermore, stable operation antral great luminouse fluxes are recognized.

In this paper, The Monte Carlo Simulation is performed in complex geometries which are composed of obstacles intercepted path of photon. Light is assumed to be particle and has particular direction and weighting value. The illuminance distribution is calculated proportional to the summation of weighting values striking area element. The result of simulation is consistent with that of experiments in a few error.

This paper develops the dynamic equivalents program combined with graphic user interface(GUI), to solve the stability of large power system. The p개posed method is coherency-based dynamic equivalents for transient stability studies. The program also provides with pull-down menu and Hangout help information for users. The developed dynamic equivalents program is suitable for the transient stability studies of a large power system with lots of data. The dynamic equivalents demonstrated over the New England system with 39 buses and 10 generators.

This paper examined the existance behavior of charged particles by measuring polarity inversion current Thermal Stimulate Current (TSC) and analysed appearance mechanism of polarity inversion current Peak and Also investigated relation between ionic space charge format ion and dielectric breakdown by measuring D.C breakdown impulse breakdown D.C - impulse superposition as a sample of FET. As a result. lie found that dielectric breakdown is likely to happen due to ionic space charge at the transient state when applied polarity inversion voltage and that charged partion of TSE Peak at the high temperature was the same as that of polarity inversion current. Also there was no effect on ionic space charge about the dielectric breakdown in stationary state when applied D.C voltage.

고전적인 제어 기법들을 이용한 전동기의 속도 제어기는 하나의 고정된 동작점에 대해서 대개 양호한 동작 특성을 얻을 수 있으나 전동기 매개변수의 섭동 및 부하 외란의 존재시 규정된 제어 동작을 유지하기가 어렵다는 단점을 갖고 있다. 따라서 본 연구에서는 이러한 단점을 극복하기 위하여 적응 제어 기법중의 하나인 기준 모델 적응 제어 (Model Reference Adaptive Control : MRAC) 방식을 직류 전동기의 속도 제어에 적용하였으며 또한, 2차 이상인 전동기의 속도 제어 시스템을 1차로 저차화시켜 제어 알고리즘의 계산에 소요되는 시간을 줄임으로써 실시간 제어가 가능토록 하였다. 제시된 기준 모델 제어 기법과 PI 제어 기법을 직류 전동기의 속도 제어에 각각 적용하고 부하의 관성변화에 다른 속도 응답 특성을 실험을 통하여 비교 검토하였다.

In this paper, the authors propose a so-called new zero voltage switching circuit topology arts an improved PWM strategy. In order to minimize voltage stress in dc-ac high switching frequency power conversion, the proposal circuit is used as interface between DC sully and the PWM inverter. The new ZVS circuit provide PWM inverter with a short zero voltage period in the dc 1ink just before inverter switches operate. By using the proposed modulating signal (transformational sinewave) art carrier sinal (sawtooth ware), the amplitude of the fundamental component is increased about 15 percent more than that of a conventional sinusoidal modulating signal and triangular carrier signal, the switching tosses is reduced. Some simulative results on computer are included to confirm the validity of the analytical results.

By using the state plane approach, the steady state analysis and design of a half bridge parallel-series (LLC-type) resonant converter (HBPSRC) operating in the continous conduction made is presented. The state-plane diagram representation of the converter response gives good insight into the converter operation. Based on this analysis, a set of steady state characteristic waves for HBPSRC is presented. A simple design procedure is given and design example for a 100watts, 30KHz HBPSRC is presented for illustrative purposes.

Adaptive active attenuation of noise in a duct is considered. A duct is modelled when the acoustic feedback exists. The secondary path transfer function is estimated using multiple model approaches. An IIR structure is assumed for the control filter, and the recursive least mean squares algorithm is used to adjust the filter coefficients.

This paper presents the effect of moisture and dust on streaming electrification in transformer oil, in order to investigate the electrification tendency of oil adding moisture and dost. Authors designed series electrification device to analyse streaming electrification phenomena easily. Experimental results show that adding of moisture and dust in oil decreased charging level and it was dominant in case of moisture.

The demand for home automation system has increased in high-rise apartment houses. Home automation system is realized a more comfortable, more secure, more economical, more convenient, and more satisfying home life. The proposed system functions are meter reading, home security, energy saving, and house control. The technical requirements and configuration of home automation system are provided.