• Proceedings of the Korea Information Processing Society Conference
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• 2023.05a
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• pp.70-71
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• 2023

최근 자동차는 다양한 서비스를 제공하는 플랫폼으로 진화하고 있다. 이러한 서비스를 제공하기 위한 기본 인프라는 차량간 통신이다. 하지만, 자동차의 높은 이동성은 무선 통신 링크의 단절을 빈번하게 일으키는 요인이 된다. 따라서 링크의 단절에 대처하기 위한 효율적인 대책이 필요하다. 본 논문은 통신 링크 단절로 인한 성능 저하를 줄이기 위한 릴레이 노드 선택 기법을 제안한다. 시뮬레이션을 통한 성능 분석에서 제안하는 기법을 통해 네트워크 성능이 향상되는 것을 보여준다.

• Proceedings of the Korea Information Processing Society Conference
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• 2023.05a
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• pp.72-73
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• 2023

도로 사고의 30% 이상이 도로 환경 조건에 의해 발생되는 것으로 추정된다. 따라서, 도로 환경의 정보는 사고를 줄이기 위한 한 방편이 될 수 있다. 본 논문은 도로 환경을 모니터링하기 위해 설치된 센서들로부터 효율적으로 데이터를 수집하기 위한 멀티 채널 토폴로지 관리 기법을 제시한다. 센서들의 밀집도가 높아져도 제안하는 기법을 통해 데이터 충돌과 에너지 소모를 줄일 수 있다. 시뮬레이션 성능 분석에서 제안하는 방식을 통해 수집되는 데이터가 증가하는 것을 확인할 수 있다.

• Journal of Welding and Joining
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• v.32 no.3
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• pp.74-80
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• 2014

Due to environmental regulations (RoHS, WEEE and ELV) of the European Union, electronics and automotive electronics have to eliminate toxic substance from their devices and system. Especially, reliability issue of lead-free solder joint is increasing in car electronics due to ELV (End-of-Life Vehicle) banning from 2016. We have prepared engine control unit (ECU) modules soldered with Sn-40Pb and Sn-3.0Ag-0.5Cu (SAC305) solders, respectively. Degradation characteristics of solder joint strength were compared with various conditions of automobile environment such as cabin and engine room. Thermal cycle test (TC, $-40^{\circ}C$ ~ ($85^{\circ}C$ and $125^{\circ}C$), 1500 cycles) were conducted with automotive company standard. To compare shear strength degradation rate with eutectic and Pb-free solder alloy, we measured shear strength of chip components and its size from cabin and engine ECU modules. Based on the TC test results, finally, we have known the difference of degradation level with solder alloys and use environmental conditions. Solder joints degradation rate of engine room ECU is superior to cabin ECU due to large CTE (coefficient of thermal expansion) mismatch in field condition. Degradation rate of engine room ECU is 50~60% larger than cabin room electronics.

• Electronics and Telecommunications Trends
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• v.36 no.3
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• pp.1-11
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• 2021

In this study, we analyze the automotive chip ecosystem that recently caused the global supply shortage, and attempt to derive policy implications for us from the conclusion. Automotive chips are critical parts that control various systems so that a vehicle can drive itself or operate with electricity. The current shortage in supply and demand for automotive chips is due to the inconsistency between supply and demand between automotive chip companies and car manufacturers. To promote the automotive chip industry, new investment incentives, tax cuts, and human resource training are needed.

• Journal of Power Electronics
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• v.19 no.3
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• pp.751-760
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• 2019

Since parameter mismatch seriously impacts the efficiency and stability of induction motor drives, it is important to accurately estimate the rotor and stator resistance. This paper introduces a method to directly calculate the rotor flux that is independent of stator and rotor resistance and electrical angle. It is based on obtaining the rotor and stator resistance using the model reference adaptive system (MRAS) method. The method has a lower computation burden and less adaptation time when compared with other rotor resistance estimation methods. This paper builds three coordinate frames to analyze the rotor flux error and rotor resistance error. A number of implementation issues are also considered.

• Electronics and Telecommunications Trends
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• v.38 no.5
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• pp.81-89
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• 2023

Software is becoming increasingly important, accounting for more than 90% of the innovations in the automotive industry nowadays. In fact, the share of software in the automotive market is estimated to be around 40%. Accordingly, the shift from hardware- to software-centric vehicles, represented by software-defined vehicles (SDVs), will drastically reorganize the automotive industry ecosystem. This article presents challenges that the automotive ecosystem needs to solve and measures that each participant in the ecosystem should adopt in line with the transition to SDVs in the automotive industry. It is expected that tier-1 suppliers will face difficulties due to the decoupling of software and hardware, and OEMs will need to strengthen cooperation to share costs and shorten development periods to cope with the huge cost of software development.

• The Transactions of the Korean Institute of Power Electronics
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• v.27 no.5
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• pp.367-375
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• 2022

Generally, a proportional-resonant controller is used to eliminate steady-state errors during the voltage-current control of a double-conversion uninterruptible power supply (UPS) in a stationary reference frame. Additionally, the feed-forward control compensating for the load current, which can be considered a disturbance of the voltage controller, can be used to improve the disturbance rejection performance. However, during the parallel operation of UPSs, circulating current can occur between UPS modules when performing both feed-forward control and droop control because feed-forward control reduces the circulating current impedance. This study proposes a feed-forward compensation technique that considers the impedance of circulating current. An additional feed-forward compensation technique is developed to enhance the disturbance rejection performance. The validity of the proposed feed-forward compensation technique is verified by the experiment results of the parallel operation of a 500 W double-conversion UPS module.

• Asian Journal of Innovation and Policy
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• v.6 no.3
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• pp.332-353
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• 2017

This paper highlights how Thailand upgrades its positions in global value chains in high-tech, mid-tech and low-tech industries represented by electronics, automotive and frozen seafood, respectively. In the electronics industry, there are not many capable firms in the upstream segment like semiconductors. Nevertheless, transnational corporations in segment like hard disk drive began to invest in process R&D and collaborate more with local suppliers, universities and public research institutes in human resource and technological development. In the automotive industry, several Japanese car manufacturers such as Toyota, Honda, Nissan, and Isuzu set up R&D/Technical centres in Thailand since 2000s. This prompted Japanese and local part suppliers to also invest more in engineering, design and development activities. Some local universities offer as well engineering programmes specifically targeting the automotive industry. In the frozen seafood industry, several Thai firms have developed new ready-to-eat products, own brands and international distribution networks. They started to become transnational corporations investing in both developing and developed countries.

• Journal of Power Electronics
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• v.2 no.3
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• pp.171-180
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• 2002

New 42-volt automotive electrical systems can provide significant improvements in vehicle performance and fuel economy. It is crucial to provide protection against load dump and other overvoltage transients in 42-volt systems. While advanced active control techniques are generally considered capable of providing such protection, the use of passive transient voltage suppression (TVS) devices as a secondary or supplementary protection means can significantly improve design flexibility and reduce system costs. This paper examines the needs and options for passive TVS devices for 42-volt applications. The limitations of the commonly available automotive TVS devices, such as Zener diodes and metal oxide varistors (MOV), are analyzed and reviewed. A new TVS device concept, based on power MOSFET and thin-film polycrystalline silicon back-to-back diode technology, is proposed to provide a better control on the clamp voltage and meet the new 42-volt specification. Both experimental and modeling results are presented. Issues related to the temperature dependence and energy absorbing capability of the new TVS device are discussed in detail. It is concluded that the proposed TVS device provides a cost-effective solution for load dump protection in 42-volt systems.

• Electronics and Telecommunications Trends
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• v.34 no.1
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• pp.123-131
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• 2019

Automotive electronics are complex and require high performance with an advanced driver assistant system (ADAS) and a functioning autonomous system. Thus, considering their complexity, the processor of the electronic control unit (ECU) requires a design that ensures high performance and reliability to ensure functional safety. This study discusses the technology used for developing a processor that can ensure functional safety of current automotive electronic systems.