• Design & Manufacturing
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• v.10 no.2
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• pp.1-5
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• 2016

High-speed and high-torque performance is required in the ultra-high speed electric injection molding machine field. To implement this performance, the big-size inverter is needed and the corresponding converter should be used. In this case, the whole cost for configuring the system will be increased. In this paper, we introduce a method which is able to reduce the energy and the cost for configuring the system using the energy regeneration. The energy regeneration method is based on reusing the regeneration power generated at the electric motor during decelerating the injection motion. In this paper, we demonstrate the effectiveness of the method by using the ultra-high speed injection motion.

• Journal of Climate Change Research
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• v.8 no.3
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• pp.265-273
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• 2017

Recently the Paris Climate Change Accord has been officially put into effect, making global efforts to implement Greenhouse Gas (GHG) reductions, and also International environmental regulations in the automotive sector will be further strengthened. The electric vehicle, which minimizes the particulate matter generated by existing internal combustion engine automobiles, is evaluated as a representative eco-friendly automobile. However, charging the battery of an electric vehicle is not fully environment-friendly if it is fueled by electricity that is being generated by fossil fuels as an energy source. The energy generated by the photovoltaic power generation system, which is an infinite clean energy, can be used to charge an electric vehicle's battery. Currently, shortage of charging facilities, time of charging, and high battery prices are the problem of activating the supply of electric vehicles. This study is to build a conjunction between the EVBSS (Electric Vehicle Battery Supply System) and ESS (Energy Storage System), which can quickly supply the photovoltaic charged battery to the required demand. If the charged battery in the Battery Swapping Station (BSS) is swapped swiftly, it will dramatically shorten the waiting time for charging the battery. As a result, if the battery is rented when it is needed, electric vehicles can be sold without the cost of a battery, which accounts for a large portion of the total cost, then the supply of electric vehicles are expected to expand. Furthermore, it will be an important alternative to maneuver climate change by minimizing GHG emissions from internal combustion engine vehicles.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.7
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• pp.659-663
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• 2015

In the present study, electroplastic tensile behaviors of aluminum 5052-H32 alloy specimens with different gage dimensions are investigated under a constant electric energy density (electric energy per unit volume). The experimental results show that equivalent electric energy densities induce nearly identical electroplastic behaviors even with different gage dimensions (length, width, or volume). Additionally, the experimental results demonstrate that the electroplastic behavior of the selected aluminum alloy is best described by the electric energy density, which is a function of current density and current duration, rather than individual current density or current duration. The results of the present study suggest that the electric energy density may replace current density and current duration as a design parameter in electrically assisted forming processes.

• Journal of Environmental Impact Assessment
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• v.20 no.4
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• pp.465-475
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• 2011

It is known that energy consumption in bottom floor of typical Korean-style apartment is the highest. Previous studies for energy consumption in accordance with floor level appear to be very limited due to the dependence on single energy variable such as electric power or LNG separately, based on past flat type of apartment. Acknowledging these constraints, an empirical study for a tower type emerged recently as new style of apartment in South Korea was conducted to demonstrate how a comprehensive evaluation for both electric power and LNG consumption can be used to assist in monitoring the total energy consumption in terms of floor specific settings. It was possible to identify that energy consumption in bottom floor is lesser than that of top floor, to the contrary, fact known from previous study. Also electric power consumption in top floor was identified as 15% higher than that of floor in the least. It is anticipated that this integrated utilization of electric power and LNG data would present more scientific and objective evidence for the energy load among floor level of tower type apartment by overcoming serious constraints suffered from the past single variable investigation. Ultimately, the result in this paper could be used as a valuable reference to providing priority for energy saving activities in top floor such as cool roof or green roof.

• The Journal of the Acoustical Society of Korea
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• v.15 no.4
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• pp.32-35
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• 1996

The pressure pulses generated from the underwater electric spark system ranged from 0.4 to 1.6kJ are measured with the variation of source depth and range. The characteristics of pressure pulses obtained through this experiment continue to show the same electric energy and depth dependence previously reported, but two particular phenomena are observed. First, it is observed that the peak pressure of the 1st bubble pulse induced from implosion is higher than that of the initial shock wave, which is particularily apparent to high electric energy more than 10kJ previous studies. Second, it has been reported that the energy ratio (potential energy of bubble/intrinsic energy of source) has some tendency to "droop" on the low electric energy as 0.02 for 5kJ and 0.01 for 1kJ but the results of the present experiment show that it continues to have the ratio of 0.01 near 1kJ again.

• International Journal of Computer Science & Network Security
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• v.22 no.3
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• pp.37-44
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• 2022

Plug-in Hybrid electric vehicles (PHEV) show great potential to reduce gas emission, improve fuel efficiency and offer more driving range flexibility. Moreover, PHEV help to preserve the eco-system, climate changes and reduce the high demand for fossil fuels. To address this; some basic components and energy resources have been used, such as batteries and proton exchange membrane (PEM) fuel cells (FCs). However, the FC remains unsatisfactory in terms of power density and response. In light of the above, an electric storage system (ESS) seems to be a promising solution to resolve this issue, especially when it comes to the transient phase. In addition to the FC, a storage system made-up of an ultra-battery UB is proposed within this paper. The association of the FC and the UB lead to the so-called Fuel Cell Battery Electric Vehicle (FCBEV). The energy consumption model of a FCBEV has been built considering the power losses of the fuel cell, electric motor, the state of charge (SOC) of the battery, and brakes. To do so, the implementing a reinforcement-learning energy management strategy (EMS) has been carried out and the fuel cell efficiency has been optimized while minimizing the hydrogen fuel consummation per 100km. Within this paper the adopted approach over numerous driving cycles of the FCBEV has shown promising results.

• Proceedings of the KIEE Conference
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• 2006.04b
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• pp.226-228
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• 2006

This paper presents the two lossless auxiliary inducors-assisted voltage source type half bridge(single ended push pull:SEPP) series resonant high frequency inverter for induction heated fixing roller in copy and printing machines. The simple high-frequency inverter treated here can completely achieve stable zero current soft switching (ZCS) commutation forwide its output power regulation ranges and load variations under constant high frequency pulse density modulation (PDM) scheme. Its transient and steady state operatprinciple is originally described and discussed for a constant high-frequency PDM control strategy under a stable ZCS operation commutation, together with its output effective power regulation charactertics-based on the high frequency PDM strategy. The experimenoperating performances of this voltage source SEPP ZCS-PDM series resonant high frequency inverter using IGBTs are illustrated as compared with computer simulation results and experimenones. Its power losses analysis and actual efficiency are evaluated and discussed on the basis of simulation and experimental results. The feasible effectiveness of this high frequency inverter appliimplemented here is proved from the practical point of view.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2011.04a
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• pp.111-115
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• 2011

The purpose of this study was the analysis of electric energy consumption with the case study of tower type apartment's opening of building surface. We analyze the relationship between tower type apartment's opening of building surface and using electric energy consumption. The results of this study are: 1) The highest energy consumption of electric energy was on August without any influence of opening types of building surface. 2) Also, the south-west sides consumption of August was 848 kWh on Type B(one side opening) and it was the highest usage. 3) A house if facing west used more electricity than facing east when its opening of building surface's datum level is facing south. However, the house of facing east used more power than west when its opening of building surface's datum level is facing north. 4) When opening of building surface is facing on north-west or north-east, the opening of building surface's side of west and east used more electric power than north-west or north-east sides.

• Journal of Power Electronics
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• v.18 no.5
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• pp.1448-1457
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• 2018

Many researchers devote themselves to develop model-predictive direct power control (MPDPC) so as to accelerate the response speed of the grid-connected systems, but they are troubled its large computing amount. On the basis of MPDPC, dual MPDPC (DMPDPC) is presented in this paper. The proposed algorithm divides the conventional MPDPC into two steps. In the first step, the optimal sector is obtained, which contains the optimal switching state in three-level converters. In the second step, the optimal switching state in the selected sector is searched to trace reference active and reactive power and balance neutral point voltage. Simulation and experiment results show that the proposed algorithm not only decreases the computational amount remarkably but also improves the steady-state performance. The dynamic response of the DMPDPC is as fast as that of the MPDPC.

• Proceedings of the KIEE Conference
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• 2006.07d
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• pp.1885-1886
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• 2006

The thermal energy from nuclear fission is transferred to the steam generator which is a kind of a large heat exchanger. After the feedwater is injected into the steam generator and absorbs the thermal energy, it is converted into the steam. This steam goes into the turbine. The balance between the generated energy and the consumed energy is required for the nuclear power plant to be stable. For the purpose of which, the feed water, a parameter for energy transfer, should be controlled in stability. Usually, the nuclear power plants are operated in base load in the view of power system for the stability of fission system. Therefore, though there will be almost no unbalance, there can be some instability from unbalance in case of startup/shutdown or disturbance. In this case, the controllability of feedwater pump is very important for the quick recover of stability.