• Proceedings of the KIPE Conference
• /
• 2014.07a
• /
• pp.538-539
• /
• 2014

The development of smart grid technologies will enable enhanced utilization of electric vehicles(EV) as portable energy storage devices which can provide power system-wide. Because significant increase of EV in the near future, V2G(Vehicle-to-Grid) system will soon become a reality. This paper presents the optimal method of a battery lifetime depending on depth of discharge(DOD) considering load leveling.

• Proceedings of the KIPE Conference
• /
• 2012.07a
• /
• pp.299-300
• /
• 2012

본 논문에서는 납 축전지를 사용하는 산업용 전기차량의 SOC(State Of Charge)를 별도의 BMS(Battery Management System)장치 없이 추정하는 방법에 대해 기술한다. SOC를 추정하기 위한 기존의 전통적인 방법들 중 전력을 적산하는 방법(Ampere hour counting)이 널리 사용되는데 이는 장치의 내, 외적인 요인에 의해 발생한 오차가 누적될 수 있다. 배터리의 전압을 측정하여 SOC를 추정하는 OCV(Open Circuit Voltage) 방법은 배터리가 안정 상태에 도달하기까지 충분한 휴지 시간이 필요해 실시간으로 적용하기 힘들다. 이 외에 칼만 필터를 이용하는 방법은 시스템을 정확히 모델링해야 하고 계산이 복잡하다는 단점이 있다. 본 연구에서는 전력을 적산하는 방법을 기본으로 하고 배터리의 전압을 적절히 이용하여 누적되는 오차를 보정하는 방법을 제안한다. 제안한 방법에 대해 시뮬레이션 하고 실제로 산업용 차량인 AC 전동 지게차로 실험하여 그 타당성을 검증 하였다.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.21 no.6
• /
• pp.147-154
• /
• 2013

This study reports on the development and investigation of a BMS module using a new algorithm on the driving performance and battery life of electric vehicles. Here, the initial SOC was calculated using an open circuit voltage (OCV) method and a current integral method was later applied to the BMS module. We verified the performance of the BMS module by comparing both the results of the in-vehicle test and the BMS simulator test. Our verification test showed good agreement between the results of experiments and simulation with a small error of ${\pm}0.8%$. Here, we confirmed that the present, newly-developed BMS module not only can predict the battery life but can also monitor SOC, pack voltage, and current temperature.

• Journal of IKEEE
• /
• v.23 no.3
• /
• pp.994-1002
• /
• 2019

In this paper, we propose the development of a power conversion system for electric power take-off (e-PTO) of agricultural electric vehicles. Most e-PTOs use commercial power $220V_{AC}$. A bidirectional power conversion system having a two-stage structure consisting of a DC-DC converter and a DC-AC inverter for supplying a high output voltage using a low battery voltage of an agricultural electric vehicle is suitable. we propose a power conversion system consisting of the one-stage dual active bridge (DAB) converter and the two-stage bidirectional full bridge inverter. In addition, we propose a soft start algorithm for reducing the inrush current generated by the link capacitor charging during the initial operation. A 3kW prototype system and its corresponding algorithms have been implemented to verify its effectiveness through experiments.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.15 no.5
• /
• pp.2545-2552
• /
• 2014

This study is aiming to suggest the effective thermal management system design technologies for the high voltage and capacity battery system of the electricity driven vehicles and introduce the theoretical designing methods. In order to investigate the effective operation of the battery system for the electricity driven vehicles, the heat generation model for Li-ion battery system using the chemical reaction while charging and discharging was suggested and the thermal loads of the heat sources (air or liquid) for cooling and heating were calculated using energy balance. Especially, the design methods for the cooling and heating of the battery system for maintaining the optimum operation temperature were investigated under heating, cooling and generated heat (during charging and discharging) conditions. The battery thermal management system for the effective battery operation of the electricity driven vehicles was suggested reasonably depending on the variation of the season and operation conditions. In addition, at the same conditions under summer season, the cooling method using the liquid and active cooling technique showed a relatively high capacity, while cooling method using the passive cooling technique showed a relatively low capacity.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.50 no.12
• /
• pp.819-828
• /
• 2022

Sensitivity of aircraft sizing depending on battery performance was studied for a generic quad tilt rotor type electric vertical takeoff and landing vehicle. The mission requirements proposed by Uber Elevate and NASA were used for initial sizing, and the calculated gross weight is ranged between 5,000lb and 11,000lb for battery specific energy range of 200-400Wh/kg in pack level and continuous discharge rate range of 4-5C. For the assumed gross weight of 7,000lb, the required battery performance was calculated with two different criteria: available power and energy, and the effects of battery specific energy and discharge rate are analyzed. The maximum discharge rate is also recommended considering failure cases such as one battery pack inoperative and one prop rotor inoperative.

• The Journal of the Convergence on Culture Technology
• /
• v.9 no.3
• /
• pp.727-730
• /
• 2023

The operation of electric automatic windows is used in harsh environments, and the energy density decreases as charging and discharging are repeated, and as soundness deteriorates due to damage to the internal separator, the vehicle's mileage decreases and the charging speed slows down, so about 5 to 10 Batteries that have been used for about a year are classified as waste batteries, and for this reason, as the risk of battery fire and explosion increases, it is essential to diagnose batteries and estimate SOH. Estimation of current battery SOH is a very important content, and it evaluates the state of the battery by measuring the time, temperature, and voltage required while repeatedly charging and discharging the battery. There are disadvantages. In this paper, measurement of discharge capacity (C-rate) using a waste battery of a Tesla car in order to predict SOH estimation of a lithium-ion battery. A Support Vector Machine (SVM), one of the machine models, was applied using the data measured from the waste battery.

• International Journal of Automotive Technology
• /
• v.4 no.1
• /
• pp.41-45
• /
• 2003

The 42V Mild Hybrid System has been released into market by Toyota for the first time in the world in 2001. The set-up employs an inverter unit to control the motor/generator (MG) electronically. The driving system called such as Toyota Mild Hybrid System (TMHS) has additional new functions to conventional internal combustion engines. When stopping vehicle, the engine stops promptly. When starting vehicle, by releasing the brake pedal MG starts the vehicle at the same time (EV-driving mode). When stepping on the accelerator pedal, or after a given period of time the engine firing occurs and the engine-driving mode starts. When running by motor, the power is supplied to the motor from 36V battery through the inverter. High outputs and instant responses are required for Inverter. At the same time, the compact volume is required to fit into the limited space of the engine room. The compact size and high output are also required to Power Capacitor used for this inverter. The power capacitors has been newly developed, shaped in "flat" type, suitably for the inverter. The points of developments on inverter and power capacitor are described in this paper.his paper.

• Proceedings of the Korean Society of Computer Information Conference
• /
• 2018.07a
• /
• pp.509-512
• /
• 2018

최근 미세먼지에 대한 관심이 높아지고 있으며, 미세먼지를 줄이기 위한 다양한 기술이 연구되고 있다. 본 연구에서는 기존 가솔린 이륜차의 단점을 극복하고 미세먼지 발생을 줄일 수 있는 배터리 교환식 이륜차 및 IoT 기반 지원시스템을 소개한다. 전기 이륜차에 탑재되는 IoT Edge device에서는 배터리 잔량, 배터리 ID, 위치 정보 등의 정보를 LTE-M 통신을 통해 IoT 클라우드에 전송하고, 배터리 교환이 필요한 경우 주변의 배터리 교환기 위치 및 교환 가능한 배터리 정보 전달 받을 수 있다. 현재 전기이륜차에 탑재될 IoT Edge device 및 사용자용 스마트폰앱을 개발하고 있으며, 배터리 교환기 및 클라우드 서비스 개발도 수행될 예정이다.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.17 no.5
• /
• pp.74-83
• /
• 2009

Recently, usage of electric and electronic system for car increases rapidly. Consequently power monitoring supplied to the system is essential for management and controlling. Generally, battery status is monitored through measuring and diagnosing the current measurement method utilizing Hall Effect. Therefore, in this paper, we analysed magnetic field to develop the solution of DC current sensor using Hall Effect which is the core of design and development. By analysing the magnetic field by FEM using Maxwell 3D software, the location of the highest output current and stable part in the Hall IC sensor was shown. Also, the optimal core design of DC current sensor using parametric and Simplex method was presented. A car battery charge and discharge process dependant on time effect on the changing of magnetic field was simulated and compared to the result from the experiment result of actual vehicle.