• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2010.06a
• /
• pp.370-370
• /
• 2010

The effects of adding higher-valence impurities on the bipolar resistive switching characteristics of Pt/$NiO_{1+x}$/TiN MIM stacks and physical properties were investigated. $NiO_{1+x}$ films with 14% W deposited at 20% oxygen partial pressure exhibited the bipolar resistance switching characteristics in Pt/$NiO_{1+x}$/TiN MIM stacks, while $NiO_{1+x}$ films with 8.2% W show unipolar resistance switching behavior. The relationship of W-doping and the crystallinity was studied by X-ray diffraction. The metallic Ni contents and $WO_x$ binding states with W amount was investigated by XPS. Our result showed that the metallic Ni, $WO_x$ binding states, and crystallinity in $NiO_{1+x}$ played an important role on the bipolar resistive switching.

• Journal of the Korean Institute of Telematics and Electronics B
• /
• v.33B no.10
• /
• pp.148-156
• /
• 1996

Increasing the switching frquency is essential to achieve the high density of switched mode power supplies, but this leads to the increase of switching losses. A number of new soft switching converters have been presented ot reduce switching losses, but most of them may have some demerits, such as the increase of voltage/current stresses and high conduction losses. To overcome these problems, the ZVT-PWM converter has recently been presented. in this paper, the operation characteristics of the ZVT-PWM boost converter is analyzed, and the steady-states (DC) and small-signal model of this converter are derived and analyzed, and then the transfer functions of this converter are derived. The transfer functions of ZVT-PWM boost converter are similar to those of the conventional PWM boost converter, but the transfer characteristics are affecsted by te duty ratio and the switching frequency.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.41 no.6
• /
• pp.600-606
• /
• 1992

The series connection of power switching semiconductor elements is essential when a high voltage converter is made, so researches are being conducted to further develop this technology. In the series connection of power switching semiconductor elements, the main problem is that simultaneous conduction at turn-on and simultaneous blocking at turn-off together with voltage balancing are unattainable because of the difference of their switching characteristics. In this paper a novel series connection algorithm is proposed, which can implement not only the synchronization of the points of turn-on and turn-off time but the dynamic voltage balancing in spite of the difference of each switching characteristics. The proposed method is that the compensated control signal is attained from the voltage feedback signal and applied to the series-connected power transistors independently. Computer simulation and experimental results verify its validity.

• Journal of Global Scholars of Marketing Science
• /
• v.12
• /
• pp.29-57
• /
• 2003

Customers of local monopolistic department store can switch their store more easily than ever due to the rapidly changing environment in distribution system represented by multi-store-strategy of large department stores, increase in discount store and growing non-store retailing system. Consequently, local department stores which enjoyed their business with little competition are forced to study and understand the customer switching behavior. This work is intended to understand the switching behavior characteristics of monopolistic local clepartrrent store users. For the end, previous researches are reviewed firstly, then characteristics of store-switching behavior of custorrers amid rapidly changing distribution environment are studied in view of the relations of dissatisfaction factor, switching barrier, switch intention and custorrer characteristics such as shopping orientation, variety-seeking behavior, degree of openess to competition and sociodemographics. Study shows that; 1) dissatisfaction factor is related to customer characteristics (shopping orientation and degree of openess to competition), 2) switching barrier recognition is related to customer characteristics (degree of openess to competition and sociodemographics) and dissatisfaction factor, 3) intention to switch to expected competitor is related to customer characteristics (shopping orientation, degree of openess to competition and sociodemographics) and switching barrier recognition. Accordingly, switch control strategy of the monopolistic local department store facing competitors' entry into market, must be made, specifically, in a way to understand customer characteristics and to make deliberate effort to reduce customer dissatisfaction.

• Proceedings of the KIPE Conference
• /
• 2000.07a
• /
• pp.150-154
• /
• 2000

This paper proposes PFC boost converter with soft switching for harmonics decrement and analyzes characteristics of PFC boost converter. In this technique power factor correction(PFC) is usually obtained by operating the PFC stage in the discontinuous current mode(DCM) Switching devices are operated for reducing current stress and electronical noise. As a result eliminate 3rd harmonic component and high power factor(PF) of the input line are verified by characteristics analysis and experimental results.

• Proceedings of the KIEE Conference
• /
• 1988.11a
• /
• pp.381-384
• /
• 1988

This paper analysed basic operation in Zero-voltages-switching quasi-resonant buck converter and considered steady state characteristics. Especially, it is confirmed that converter operating at maximum 1MHz switching frequency in load characteristics. In this paper, a novel slope method is proposed and implemented in regulation characteristics analysis. It is proved that experimenental results coincide with theory results.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.67 no.2
• /
• pp.63-69
• /
• 2018

In this paper, the operation principle of a bi-directional switch type resonant AC link snubber circuit was described, together with the practical design procedure, which employs in the proposed power module bridge package type resonant AC link snubber. The novel prototype of power module bridge package type resonant AC link snubber-assisted voltage type sinewave soft switching PWM inverter using IGBT power module was demonstrated herein. It was verified that both the auxiliary power switches in this resonant AC link snubber circuit and the main power switches commutate under the condition of soft switching commutation principle. In addition, the power losses of the new soft switching inverter treated here were analyzed by implementing the experimental data of the IGBT and diode v-i characteristics in addition to switching power loss characteristics into our original computer simulation software developed by the authors. Then, the voltage type sinewave soft switching PWM inverter was high efficiency than that of hard switching PWM inverter, along with performance operation waveforms. In the future, the comparative feasibility study of power module bridge type resonant AC link snubber and its related soft switching inverter in addition to the other types resonant snubber assisted soft switching inverter should be done from a practical point of view.

• Journal of Power Electronics
• /
• v.10 no.6
• /
• pp.749-761
• /
• 2010

The switching frequency of a power device is a very important parameter in the design of a parallel active power filter (PAPF), but so far, very little discussion has been conducted on it in a quantitative manner in previous publications. In this paper, an extensive analysis on the effects of the switching frequency on the performance of a PAPF is made, and a specification of the switching frequency values with different compensation results is presented. A first-order inertia element and a second-order oscillation element are considered as approximate models of a PAPF, respectively. The compensation characteristic for each order of harmonic current is obtained at different switching frequencies. Then, the THDs of each model for the system loads of a rectifier with resistance and inductance loads are proposed. The compensation results of a PAPF controlled as a first-order inertia element are better than those of a PAPF controlled as a second-order oscillation element. With two types of system loads which are rectifier with resistance and inductance loads and rectifier with resistance, inductance and capacitance loads, the THDs of the source current after compensation are presented with different switching frequencies. The compensation characteristics for the most widely used digital control system are investigated. The situation with an analog control is the theoretical characteristic and it is the best situation. The compensation characteristic of the digital control is worse than the compensation characteristic of the theoretical characteristic. Based on these analyses, the specifications of compensation characteristics with different switching frequencies are quite straightforward. Finally, a practical design example is studied to verify the application.

• Proceedings of the KIPE Conference
• /
• 2010.07a
• /
• pp.71-72
• /
• 2010

This paper deals with the SCR thyristor switching characteristics of a 3-phase voltage disturbance generator. The series transformers of the generator require bypass SCR thyristors to provide the source voltage to the output terminal in normal operating mode. The SCR thyristor switching characteristics is quite different according to the connection point to the series transformer. The switching characteristics is analysed and verified through simulation results.

• Proceedings of the KIPE Conference
• /
• 2010.07a
• /
• pp.532-533
• /
• 2010

This paper deals with the SCR thyristor switching characteristics of a 3-phase voltage disturbance generator. The series transformers of the generator require bypass SCR thyristors to provide the source voltage to the output terminal in normal operating mode. The SCR thyristor switching characteristics is quite different according to the connection point to the series transformer. The switching characteristics is analysed and verified through simulation results.