• Corrosion Science and Technology
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• 제18권4호
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• pp.117-120
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• 2019

Considering the tendency of development of electrification vehicles, development and verification of new evaluation technology is needed because of new technology applications. Recently, as the battery package is set outdoors of an electric vehicle, such vehicles are exposed to corrosive environments. Among major components connected to the battery package, rust prevention of high-voltage cables and connectors is considered the most important issue. For example, if corrosion of high voltage cable connectors occurs, the corrosion durability assessment of using an electric vehicle will be different from general environmental corrosion phenomena. The purpose of this study is to investigate the corrosion mechanism of high voltage cable connectors of an electric vehicle under various driving environments (road surface vibration, corrosion environment, current conduction by stray current, etc.) and develop an optimal rust prevention solution. To improve our parts test method, we have proposed a realistic test method to reproduce actual electric vehicle corrosion issues based on the principle test.

• Journal of Positioning, Navigation, and Timing
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• 제10권4호
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• pp.235-242
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• 2021

Unmanned Aerial Vehicles (UAVs), which were used for military purposes, are gradually expanding their application fields under the influence of electrification and digitalization. Starting from the field of aerial imaging and Intelligence Surveillance and Reconnaissance (ISR) mission, nowadays the possibility of Urban Air Mobility (UAM), which transports passengers and cargo with drones, is widely under discussion. In order to occupy the rapidly growing global unmanned aerial vehicle market in advance, it is necessary to secure core technologies and develop key UAVs components based on the new technologies. In the navigation field, it is necessary to secure a precise position with guaranteed reliability and continuity, unrelated to the operating environments. The reliability and continuity should be secured in the algorithm level and in the H/W component levels also. In order to achieve this technical goal, the Ministry of Science and ICT has launched the 'Unmanned Vehicle Core Technology Research and Development Program' in 2019 to support the R&D on the unmanned vehicle technologies. In this paper, authors introduce the unmanned vehicle core technology research and development program to the related researchers. The authors summarize the backgrounds of the program and show the technological tasks and objectives on the sub-programs in the unmanned vehicle navigation program. We present the program schedules especially focused on the test and evaluation of the developed technologies and components.

• Coupled systems mechanics
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• 제7권6호
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• pp.707-729
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• 2018

The semi-active optimal vibration control of nonlinear torsion-bar suspension vehicle systems under random road excitations is an important research subject, and the boundedness of MR dampers and the uncertainty of vehicle systems are necessary to consider. In this paper, the differential equations of motion of the coupling torsion-bar suspension vehicle system with MR damper under random road excitation are derived and then transformed into strongly nonlinear stochastic coupling vibration equations. The dynamical programming equation is derived based on the stochastic dynamical programming principle firstly for the nonlinear stochastic system. The semi-active bounded parametric optimal control law is determined by the programming equation and MR damper dynamics. Then for the uncertain nonlinear stochastic system, the minimax dynamical programming equation is derived based on the minimax stochastic dynamical programming principle. The worst-case disturbances and corresponding semi-active bounded parametric optimal control are obtained from the programming equation under the bounded disturbance constraints and MR damper dynamics. The control strategy for the nonlinear stochastic vibration of the uncertain torsion-bar suspension vehicle system is developed. The good effectiveness of the proposed control is illustrated with numerical results. The control performances for the vehicle system with different bounds of MR damper under different vehicle speeds and random road excitations are discussed.

• Journal of East Asia Management
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• 제5권1호
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• pp.75-90
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• 2024

About 100 years after the start of mass production by American car maker Ford in 1913, the automobile industry has come to a major transformation in 100 years. In this transformation period, automakers are facing the biggest challenge of converting power sources, the basis of automobiles, from existing internal combustion engines to electric vehicles. Hybrid vehicles have been released in Japan since the late 1990s, and changes in automobile power sources have occurred early. In order to gain global leadership in hybrid vehicles, Japanese automakers and the Japanese government joined forces to promote the growth of the domestic hybrid vehicle market. The government has implemented a policy to substantially subsidize the high price of hybrid cars compared to internal combustion engine cars by providing purchase subsidies and tax benefits to buyers. Toyota has increased its line-up of hybrid cars around the Prius and has further strengthened communication with customers for the sale of hybrid vehicles. As a result of continuing these efforts for about 20 years, the percentage of Japan's hybrid vehicle market in 2022 reached 51% for passenger cars. Recently, each country has been setting and promoting aggressive goals for electric vehicles that require a wider range of physical and institutional infrastructure than hybrid vehicles. This study aims to assess the growth of electric vehicles by looking at the trend of hybrid vehicles and how they've been distributed in the Japanese market.

• Journal of Digital Convergence
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• 제19권11호
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• pp.301-313
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• 2021

The automotive industry is facing a paradigm shift, changing from owning to sharing and from manufacturing to service. However, it is hard to conclude that the economic value of smart mobility service is always positive to users. Cost related to owing or share a vehicle is very hard to estimate from the perspective of potential users as well as the benefit of the service. Focusing on the cost side of the story, this study develops a cost estimating model based on three main factors: electrification, advanced driving assistant systems (ADAS) function, and participation of ride-sharing service. As a result of the model analysis, low cost was estimated as a result when receiving cost benefits such as electrification and ride-sharing participation. Various factors were analyzed through sensitivity analysis also. These results can provide useful insights into the cost prediction and strategies for potential users and manufacturers on smart mobility service market.

• Journal of Electrical Engineering and Technology
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• 제13권6호
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• pp.2553-2560
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• 2018

In Korea, there are no instances where a hydrogen fuel cell power generation system has been used in a railway vehicle. Only the basic topology has been studied. In the previous study, conventional converters using a single switch were applied to the fuel cell power generation system. Therefore, current stress on the switch at converter on-off transitions would be large when controlling a large-capacity railway vehicle. In addition, since the input side ripple is also large, there is a problem with a shortening of the lifetime of both the fuel cell power generation system and the inductor. In this paper, a soft-switching transformer inductor boost converter for fuel cell powered railway vehicles was proposed. A technique to reduce both the switching current stress generated during on-off transitions, and the input ripple current flowing in the inductor were studied. The soft-switching TIB converter uses a transformer-type inductor to configure the entire circuit in an interleaved method, and reduces both input current ripple and the current ripple of the inductor and switch.

• Journal of Electrical Engineering and Technology
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• 제12권5호
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• pp.1916-1924
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• 2017

Fossil oil, as the main energy of transportation, is destined to be exhausted. The electrification of transportation is a sustainable solution to the energy crisis, since electric power could be acquired from the inexhaustible sun, wind and water. Among all the problems that hinder the development of Electric Vehicle (EV) industry, charging issue might be the most prominent one. In this paper, the service process of a charging station with Battery Energy Storage System (BESS) is analyzed by means of $Cram{\acute{e}}r$ - Lundberg model which has been intensively utilized in ruin theory. The service quality is proposed in two dimensions: the service efficiency and the service reliability. The arrival rate and State of Charge (SOC) upon arrival are derived from 2009 National Household Travel Survey (NHTS). The simulations are performed to show how the service quality is determined by the system parameters such as the number of servers, the service rate, the initial capacity, the charge rate and the maximum waiting time. At last, the economic analysis of the system is conducted and the best combination of the system parameters are given.

• The Transactions of the Korean Institute of Power Electronics
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• 제27권1호
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• pp.1-8
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• 2022

Recently, photovoltaic (PV) systems have been gradually applied in eco-friendly vehicle applications to improve fuel economy. The relevant market is expected to continue to grow because the installation of large-capacity PV systems to other eco-friendly vehicles, such as electric buses and trains, is being considered. However, in a PV system, power imbalance between submodules and low power generation efficiency occur due to factors such as cell aging, contamination, and shading. To resolve this problem, various differential power processing (DPP) converters have been researched and developed. However, conventional DPP converters suffer from large volume and low efficiency. Therefore, to apply DPP converters to eco-friendly vehicles, increasing efficiency and reducing volume and price compared with existing DPP converters is necessary. In this paper, a novel DPP converter with an integrated transformer is proposed and analyzed. The proposed DPP converter uses a single magnetic component by integrating transformers and secondary sides of conventional DPP converters. Therefore, the proposed DPP converter shows high power density and high efficiency, and it is suitable for PV systems in eco-friendly vehicle applications.

• Proceedings of the KIPE Conference
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• 전력전자학회 2013년도 추계학술대회 논문집
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• pp.23-24
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• 2013

In recent years, ISG (Integrated Starter and Generator) system receives a great attention for electric electrification of normal gasoline vehicle. As a cost-effect machine design, an ISG without a permanent magnet is considered. A 12slot-10pole field-excitation flux-switching synchronous machine (FEFSSM) is designed and analyzed via JMAG. The active parts such as the field excitation coil and armature coil are located on the stator. The rotor part consisting of single piece iron makes it more robust and suitable to apply for high speed motor drive system application coupled with reduction belt. The design target is the motor with a maximum torque of 40Nm, a maximum power of 10kW and a maximum speed of 14000 rpm. In this paper, design optimization method is proposed for high torque capability.

• Transactions of the Korean Society of Automotive Engineers
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• 제21권4호
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• pp.120-127
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• 2013

Hybrid electric vehicles have applied electric parts for saving fuel consumption and reducing levels of environmental pollution. Electrification of automobiles is indispensable for entering into global market because of enhanced environment restriction. ISG (Integrated Starter & Generator) system is one of main electric parts and can improve fuel efficiency more than other components by using Idle Stop & Go function and regenerative braking system. However, if ISG motor and inverter work under the continuously high load condition, it will make them the decrease of performance and durability. So the ISG motor and inverter need to properly design the cooling system of them. In this study, we suggested the enhancement points by modifying the thermal design of ISG motor and then confirmed the improvement of the cooling performance.