• Journal of the Semiconductor & Display Technology
• /
• v.19 no.1
• /
• pp.42-48
• /
• 2020

As global warming accelerates, eco-friendly electric cars are being developed to reduce carbon dioxide emissions, and power conversion inverters are used to drive motors. Among inverter components, DC-link capacitor is heated by high current usage, which causes problems such as performance and life-saving of inverter. Although metal cases with good thermal performance have been used to solve this problem, it is difficult to apply them in practice due to insulation problems with other parts. In this paper, the Heat-Generation influence factor of DC-link capacitor is analyzed. Variables on heat-generation are set at 3 levels for film width, inductance, and film thickness. Box-Behnken to 13 tests using the design and minimal deviations, e.g. through the experiment three times by each level. The surface of the film k type by attaching the sensor current is measured temperature. Capacitance was set to a minimum level of 200 ㎌ and had a frequency of 16 kHz with Worst case, ambient temperature of 85℃ and a ripple current of 50 Ams was applied. The temperature at the measurement point was collected in the data logger after sampling at 1 minute intervals for 2 hours after saturation with the ambient temperature. This experiment confirmed that setup factors are correlated with heat-generation.

• Journal of Welding and Joining
• /
• v.31 no.4
• /
• pp.54-61
• /
• 2013

This paper reports mild steel(SPHC) and stainless steel(STS304) sheets commonly used for railroad cars or commercial vehicles such as in the automobile and shipbuilding industries. The sheets are used in these applications, which are mainly fabricated using the shielded metal arc welding(SMAW) of dissimilar materials. It also reports an interesting application of Laser Induced Breakdown Spectroscopy(LIBS) in order to determine the elemental composition diffusion of SPHC and STS304. Arc blow produced by magnetic force during the electric arc welding prevents the formation from a sound weldment. In particular, the mechanical properties of the joint are influenced by not only by geometrical and mechanical factors but also the welding conditions for the arc welded joint. Therefore, the mechanical properties and performance are evaluated by performing a physicochemical component analysis. And they increase in accordance with content of elements and microstructure in mild steel. As results, appropriate range for magnetic fields could be achieved. Therefore, the effect of magnetic force in a butt weld of mild steel plates was investigated by comparing to the measured data.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.12 no.2
• /
• pp.309-314
• /
• 2017

Recently, the fields such as the service robot, the autonomous driving electric car, and the torpedo ladle cars operated autonomously to enhance the efficiency of management of the steel mill are receiving great attention. But development of automatic power supply that doesn't need human intervention be a problem. In this paper, a position tracking technology of power connector receptacle based on the computer vision is studied which can recognize and identify the position of the power connector receptacle, and finally its possibility is verified using OpenCV program.

• Proceedings of the KSME Conference
• /
• 2004.04a
• /
• pp.2076-2081
• /
• 2004

Future exhaust gas limits for diesel-driven passenger cars will force the automotive industry to significantly improve the performance of engine. Since modern common-rail injection systems deliver more degrees of freedom referring to the injection process, again the optimization of the injection process could offer a possibility to meet the exhaust gas limits. This study describes the characteristic the pilot spray structure of piezo-driven injector for a passenger car common-rail system to be applicable multiple injection caused by fast response rather than solenoid-driven injector. The piezo-driven injector is prototype injector with same needle chamber of solenoid injector and the solenoid-driven one is commercial injector. The pilot spray characteristic such as spray tip penetration, spray speed, spray angle were obtained by spray images, which is measured by the Mie scattering method with optical system for high-speed temporal photography. It was found that piezo-driven injector effected electric change as important factor and showed faster response than solenoid-driven injector.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.12 no.6
• /
• pp.60-68
• /
• 2013

The present research aims to develop aluminum disc brakes to replace existing cast iron disc brakes in automobiles. The foundation for developing an aluminum disc is laid by investigating the performance characteristics of existing cast iron disc brakes and comparing those characteristics with those of aluminum disc brakes. This study involves FEM thermal/structural analysis of disc materials and experimental tests using a brake dynamometer. The results of this study show that, aluminum discs have not only better thermal/mechanical properties than existing cast iron discs, including better heat, wear, and crack resistance, but also that aluminum discs. Weigh less than existing cast iron discs, which results in improved maneuverability. Aluminum discs will become a more essential part of automobiles as electric cars become the major means of transportation.

• Proceedings of the KSR Conference
• /
• 2006.11b
• /
• pp.755-770
• /
• 2006

1974. 8.15 SeoulMetro, beginning with the first electric railway established at six cities, so it is managing mass transportation of traffic. Especially, in case of seoul, It is managing that from one to eight lines, 286.9km, 265 stations have installed and now it is carrying about 5.5million of passengers everyday, and 2,000million passengers a year. So accident is increasing from the station every year. For this measure, SeoulMetro prepares safety fence for passengers crash but, as suicides or people who watch the accident took place, for at the bottom of passengers crash protection, PSD installing is needed. Even though, PSD is managing ATO section but, in controlling SeoulMetro, one to four lines sections are (ATS, ATC)section. Between as ATS, ATC section, ATO section, subway gate and PSD must have opened and crossed always at the time. And the interlock control corrosion protection gate, managing skills with installation, method, using in history, apply to 10rail cars one train sets, and maximum applying 224% sections of passengers congested that consideration is to be needed. So 2004, SeoulMetro improved technology and basic design of PSD at ATS section. Based on this, from 2005.4 to 2006.6, using subway 2lines per 12stations set the model installation(full type 11stations, half type 1station) After installing in case of success, it is going about to suggest that effective analysis and hereafter subject.

• Journal of Drive and Control
• /
• v.14 no.4
• /
• pp.29-36
• /
• 2017

Electronic control technologies that have long been developed for passenger cars spread to construction equipment and agricultural vehicles because of its outstanding performance achieved by embedded software. Especially, system program of transmission control unit (TCU) plays a crucial role for the superb shift quality, driving performance and fuel efficiency, etc. Since the control algorithm is embedded in software that is rarely analyzed, development of such a TCU cannot be conducted by conventional reverse engineering. Transmission simulator is a kind of electronic device that simulates the electric signals including driver operation command and output of various sensors installed in transmission. Standalone TCU can be run in normal operation mode with the signals provided by transmission simulator. In this research, transmission simulator for the tracked vehicle TCU is developed for the analysis of shift control algorithm from the experiments with standalone TCU. It was confirmed that shift experimental data for the simulator setup conditions can be used for the analysis of control algorithms on proportional solenoid valves and shift map.

• Journal of Power Electronics
• /
• v.19 no.6
• /
• pp.1536-1543
• /
• 2019

This paper presents an improved torque predictive control (TPC) for permanent magnet synchronous motors (PMSMs) using an indirect matrix converter (IMC). The IMC has characteristics such as a high power density and sinusoidal waveforms of the input-output currents. Additionally, this configuration does not have any DC-link capacitors. Due to these advantages of the IMC, it is used in various application field such as electric vehicles and railway cars. Recently, research on various torque control methods for PMSM drives using an IMC is being actively pursued. In this paper, an improved TPC method for PMSM drives using an IMC is proposed. In the improved TPC method, the magnitudes of the voltage vectors applied to control the torque and flux of the PMSM are adjusted depending on the PMSM torque control such as the steady state and transient response. Therefore, it is able to reduce the ripples of the output current and torque in the low-speed and high-speed load ranges. Additionally, the improved TPC can improve the dynamic torque response when compared with the conventional TPC. The effectiveness of the improved TPC method is verified by experimental results.

• Proceedings of the KSR Conference
• /
• 2008.11b
• /
• pp.1525-1538
• /
• 2008

Currently, it has been a fashion to include RAMS of rolling stock in the order for purchasing the rolling stock. However, it's only to suggest a qualitative value or an ideal target without giving or demonstrating actual RAMS target, with only demonstrating passive RAMS by the data provided by the manufacturer. In the case of KTX project of 100 cars of KTX-II contracted in June 2006, their target has been suggested from the previous RAMS application standard and it aimed to achieve the reliability level of equivalent high speed rolling stock. Afterward, as actual KTX-II RAMS Plan and RAMS Demonstration Plan has been prepared and approved, it has been the first problem to secure the reliability and safety in order to introduce the new high speed rolling stock(KTX-II) successfully and we actually tried to apply overseas RAMS standard, KTX samples, electric railcar MTRC and rolling stock samples. This Report was dealt world trends of Railway RAMS standard, KTX-II RAMS Specifications, the present condition of KTX-II RAMS performance and development a way of KTX-II RAMS, We hope the "KTX-II RAMS Application Standard for Safety of Passenger Transportation Service" is served as an opportunity for the basic research for establishing and demonstrating RAMS target of components or parts composing the rolling stock system.

• International Journal of Computer Science & Network Security
• /
• v.21 no.7
• /
• pp.297-304
• /
• 2021

In a duopoly situation, one firm can gain competitive advantage by attracting the price-sensitive customers from its competitor leading to higher profits through higher sale revenue for the competing company. A simulation study in which there are two electric car manufacturers with agent based modelling was conducted in order to verify this contention. The first step consisted of defining the baseline. Simulations of 1000 times and agent-based modelling were conducted with the assumption that company 1 reduced its price to the maximum of 20% thereby contributing to the switch-over of a maximum of 40% of the price sensitive customers of company 2. The results of 1000 simulations and agent-based modelling highlighted that price reduction by company 1 resulted in a significant increase in the number of customers, presumably due to switch-over from company 2 and there was a corresponding increase in revenues from both of the sales avenues. Thus, Company 1 achieved competitive advantage by marketing its cars to the customers of Company 2 using price reduction strategy to attract them. This study has ramifications for companies that aim to sway the price sensitive customers from a competitor.