• Proceedings of the KIPE Conference
• /
• 2013.07a
• /
• pp.137-138
• /
• 2013

This paper proposes the single-phase double-conversion UPS(Uninterruptible Power Supply) with ESS(Energy Storage System). The Proposed system is operating in three modes, which are normal mode, battery mode, and bypass mode. Not only in black-out but also in peak load times, the system is operating in battery mode which is using the stored energy of the battery to manage the power effectively. The validity of proposed system could be verified by simulations and experiments.

• Journal of the Semiconductor & Display Technology
• /
• v.10 no.2
• /
• pp.13-17
• /
• 2011

We have developed a new energy-consuming monitoring system that has made it possible to measure the energy consumption of a gas scrubber, one of semiconductor processing equipments, and installed this system to the gas scrubber under operating at a manufacture site. Using this system, we have measured consumptions of electric power and processing gas consumed at standby to operating mode. In case of the gas scrubber, processing gas flows continuously into it at standby and operating mode. Therefore, if the electric power has been supplied, the processing gas can flows into the device for 24 hours. Moreover, at operating of gas scrubber, the amount of electricity consumption is 5 kWh. At Standby of gas scrubber, it spends 3kwh. It is certain that the energy consumption is greater at operating mode than at standby mode. The carbon emission rates from 24 hour gas scrubber operation are 236 $kgCO_2$/day of $N_2$, 57 $kgCO_2$/day of electric power and 0.001 $kgCO_2$/day of cooling water. Most of carbon is emitted from $N_2$ gas and electric power consumption.

• The KSFM Journal of Fluid Machinery
• /
• v.18 no.4
• /
• pp.49-55
• /
• 2015

The pumped storage plant operates with quick change of the discharge as well as quick changes between pump mode and turbine mode. This study focuses on the cavitation analysis of a pump-turbine model because in turbo-machinery, cavitation can reduce the performance and shorten service life. The pump-turbine model system consists of 7 blades, 20 stay vanes (including tongue) and 20 guide vanes. This study adopts the Rayleigh-Plesset model as a cavitation model, which illustrates cavitation by using the air volume fraction method. The pump mode and turbine mode at the operating condition of partial loading, normal and excessive loading are analyzed to investigate the cavitation performance of the pump-turbine. It was observed that this pump-turbine design showed very good cavitation characteristics with no cavitation bubbles in all operating conditions. Overall value of air volume fraction of both mode at different operating condition are lower than 1, which confirms low possibility of cavitation occurrence at current situation.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.7 no.8
• /
• pp.1726-1731
• /
• 2003

The firewall is generally used to protect the internal information system from intruders and hackers who attack through the Internet. However, it is very difficult for a user to verify the performance of the firewall as well as the difference of the performance for the operating mode such as Bridge Mode and Gateway Mode. In this paper, the performance of a firewall on the operating systems or windows 2000, Linux, and FreeBSD is compared. Finally, The performance of a firewall on the FreeBSD is compared at different operating modes and the effect of the number of rules by testing throughput of a firewall is analyzed.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.2 no.6
• /
• pp.9-17
• /
• 1994

In this study, a shifting algorithm of CVT was suggested for the two(2) driving modes : (1) power mode and (2) economy mode. Shifting algorithm must be obtained to make the engine run on the optimum operating line for the desired performance of the vehicle. Optimum operating lines of the engine were obtained by connecting the shortest way of the iso-power lines for the power mode and by connecting the shortest way of the BSFC curves for the economy mode. Also dynamic model of CVT vehicle was derived considering the throttle and the brake operation. By using the shifting algorithm and the CVT vehicle model, numerical simulations were performed to estimate the performance of CVT. Simulation results showed that comparing the performance of the conventional 4-speed automatic transmission, acceleration performance of the CVT vehicle was almost same with the AT vehicle for the power mode and the fuel economy of CVT was 14% superior than that of AT for the economy mode.

• Proceedings of the KIEE Conference
• /
• 2001.07b
• /
• pp.1126-1128
• /
• 2001

A single-stage high-power-factor electron ic ballast operating in critical conduction mode is presented in this paper. The proposed topology is based on integration of a boost-like converter and a LCC Type half-bridge serial resonant inverter. The power-factor-correction(PFC) stage is a boost-like converter operating in critical conduction mode for positive and negative half cycle voltage respectively at line frequency (60Hz) so that a high power factor is achieved naturally. The simulated and experimental results for 100w fluorescent lamps operating at 42kHz switching frequency and 220V line voltage have been obtained.

• Proceedings of the KIEE Conference
• /
• 1990.11a
• /
• pp.267-271
• /
• 1990

This paper describes a 3-Phase Quasi-Resonant DC Link Inverter (3-phase QRI), which has two operating modes, ie. inverting mode and rectifying mode. First the 3-Phase QRI is simplified and the resonant circuit is analyzed in comparison with two resonant DC-to-DC converters. This analysis shows that the maximum voltage of resonant capacitor is limited to twice the input voltage irrespective of operating modes. A new simple control method in rectifying mode is suggested, which does not require any other element in power circuit. The characteristic of 3-Phase Quasi Resonant Inverter has been verified by simulation using the proposed control method.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.40 no.5
• /
• pp.479-488
• /
• 1991

A novel three-phase quasi-resonant dc link inverter (QRI)with a switch connected between dc voltage source and resonant inductor is proposed. According to the state of switching and load current, the operating mode of the proposed inverter scheme is classified into free-wheeling, inverting, and rectifying mode. By examining the behavior of the circuit in each operating mode, an equivalent circuit which represents all the modes in a unified manner is derived. The operating principle of QRI at inverting mode is analyzed, and it is shown that the maximum voltage of resonant dc link is confined to twice the dc source voltage and that both the zero voltage switching of inverter and the zero current switching of inserted switch are guaranteed. An appropriate current control algorithm is suggested, and the opeating characteristics of proposed resonant inverter are verified through both simulation and experiment.

• Journal of Advanced Marine Engineering and Technology
• /
• v.26 no.3
• /
• pp.313-319
• /
• 2002

Since the oil crisis in 1970, a great deal of effort has been made to develop automatic electric load sharing systems as a part of the efforts to save energy. A large scale electric generating system composes more than two generators whose characteristics may be different. When such a system is operated individually or in parallel, the lagrange multiplier's method has difficulty in achieving optimal load distribution because generators usually have the limitations of the operating range with inequality constraints. Therefore, a suitable operating mode of generators has to be decided according to the selection of the generators to meet electric power requirements at the minimum cost. In this study, a method which solves the optimal electric load distribution problem using the dynamic programming technique is proposed. This study also shows that the dynamic programming method has an advantage in dealing with the optimal load distribution problem under the limitations of the operating range with inequality constraints including generator operation mode. In this study, generator operating cost curve of second order equation by shop trial test results of diesel generators are used. The results indicate that the proposed method can be applied to the ship's electric generating system.

• The Journal of the Convergence on Culture Technology
• /
• v.9 no.6
• /
• pp.1049-1055
• /
• 2023

The utilization of agricultural drones for pest control operations has been increasing due to its economic efficiency. However, variations in the effectiveness of these operations occur depending on the operator's proficiency. In this study, we applied a smart operating mode to overcome the limitations of manual flight mode and proposed a numerical model. Through comparative validation with prior research, we conducted experimental verification. As a result, we determined the spray time and calculation of spray area for each drone model. We selected a drone for pest control with a high similarity to the numerical model and verified it experimentally. Through this, we confirmed that the application of the smart operating mode is more effective in terms of calculation of spray area and operational efficiency compared to manual flight mode.