• Title/Summary/Keyword: Hybrid Vehicles

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Analysis of Fault Diagnosis of Regenerative Braking System for Fuel Cell Vehicle with EMB System (전기기계 브레이크가 적용된 연료전지 자동차의 회생제동 시스템의 고장해석)

  • Song, H.Y.;Choi, J.H.;Hwang, S.H.;Jeon, K.K.;Choi, S.J.
    • Journal of Drive and Control
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    • v.9 no.4
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    • pp.8-13
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    • 2012
  • Recently, researches about the eco-friendly vehicles such as hybrid electric vehicle, fuel cell vehicle and electric vehicle have been actively carried out. The regenerative braking system is a key technology to improve the vehicle energy utilization efficiency because it transforms the kinetic energy to the electric energy through the electric motor. This new braking system requires cooperative control between electric controlled brake and regenerative brake. Therefore, it is necessary to establish fault-diagnosis and fail-safe evaluation criteria to secure reliability of the regenerative braking system. In this paper, the failure types and causes in regenerative braking system were analyzed. The transient behavior characteristics were examined based on fault-diagnosis and fail-safe upon failure of regenerative braking system.

State-of-charge Estimation for Lithium-ion Batteries Using a Multi-state Closed-loop Observer

  • Zhao, Yulan;Yun, Haitao;Liu, Shude;Jiao, Huirong;Wang, Chengzhen
    • Journal of Power Electronics
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    • v.14 no.5
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    • pp.1038-1046
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    • 2014
  • Lithium-ion batteries are widely used in hybrid and pure electric vehicles. State-of-charge (SOC) estimation is a fundamental issue in vehicle power train control and battery management systems. This study proposes a novel model-based SOC estimation method that applies closed-loop state observer theory and a comprehensive battery model. The state-space model of lithium-ion battery is developed based on a three-order resistor-capacitor equivalent circuit model. The least square algorithm is used to identify model parameters. A multi-state closed-loop state observer is designed to predict the open-circuit voltage (OCV) of a battery based on the battery state-space model. Battery SOC can then be estimated based on the corresponding relationship between battery OCV and SOC. Finally, practical driving tests that use two types of typical driving cycle are performed to verify the proposed SOC estimation method. Test results prove that the proposed estimation method is reasonably accurate and exhibits accuracy in estimating SOC within 2% under different driving cycles.

A Study on the Direct Torque Control for Fe-Phase IPM (5상 매입형 영구자석 동기전동기의 직접토크제어에 대한 연구)

  • Kim, Nam-Hun;Baik, Won-Sik;Kim, Dong-Hee;Kim, Min-Huei;Hwang, Don-Ha;Choi, Kyeong-Ho
    • Proceedings of the KIEE Conference
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    • 2005.04a
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    • pp.210-212
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    • 2005
  • 최근 급속도로 발전하고 있는 산업분야에서 요구되는 서보 시스템에서 빠른 응답특성, 고도의 정밀성 그리고 안전성에 대한 요구가 커지고 있는 실정이다. 본 논문에서는 이러한 요구에 따라 5상 IPM(Five-phase IPM)의 DTC(Direct torque control)에 대해 고찰하였으며, Texas Instruments사에서 전동기 제어 전용으로 개발된 DSP칩인 TMS320F2812를 이용하여 디지털적으로 제어 알고리즘을 구성하였다. 5상 전동기는 현재 산업현장에서 일반적으로 널리 사용되고 있는 삼상 전동기에 비해 안정성이 높고, 상당 전압의 변화 없이 고정자 전류를 줄일 수 있고, 토크 맥동의 주파수를 높이고 결과적으로 토크의 크기를 감소시킬 수 있다는 여러 가지 장점을 가지고 있으며, 특히 안정성을 요구하는 항공기(Aerospace applications), 전기자동차 및 하이브리드 자동차(Electric or hybrid vehicles)등의 특수한 영역에서 요구가 계속 증가되고 있다. 따라서 본 논문에서는 5상 IPM의 DTC에 대한 특성을 실험을 통하여 확인하였다.

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Strategic coating of NdFeB magnets with Dy to improve the coercivity of permanent magnets

  • Ucar, Huseyin;Parker, David S.;Nlebedim, I.C.;McCallum, R.W.;McCall, S.K.;Parans Paranthaman, M.
    • Advances in materials Research
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    • v.4 no.4
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    • pp.227-233
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    • 2015
  • We present a method, supported by theoretical analysis, for optimizing the usage of the critical rare earth element dysprosium in $Nd_2Fe_{14}B$ (NdFeB)-based permanent magnets. In this method, we use Dy selectively in locations such as magnet edges and faces, where demagnetization factors are largest, rather than uniformly throughout the bulk sample. A200 nm thick Dy film was sputtered onto a commercial N-38, NdFeB magnets with a thickness of 3 mm and post-annealed at temperatures from $600-700^{\circ}C$. Magnets displayed enhanced coercivities after post-annealing and as much as a 5 % increase in the energy product, while requiring a total Dy content of 0.06 wt. % - a small fraction of that used in the commercial grade Dy-NdFeB magnets. By assuming all Dy diffused into NdFeB magnets, the improvement in energy product corresponds to a saving of over 1% Dy (critical element). Magnets manufactured using this technique will therefore be higher performing which would potentially broaden the application space of these magnets in the traction motors of hybrid and pure electric vehicles, and wind generators.

Improvement of Microstructural Anisotropy of Nd-Fe-B-Ga-Nb Alloy by the Control of Hydrogen Reaction (수소반응속도 제어에 의한 Nd-Fe-B-Ga-Nb 합금의 미세조직 이방화율 향상에 관한 연구)

  • Lee, S.H.;Kim, D.H.;Yu, J.H.;Lee, D.W.;Kim, B.K.
    • Journal of Powder Materials
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    • v.17 no.1
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    • pp.23-28
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    • 2010
  • HDDR treated anisotropic Nd-Fe-B powders have been widely used for the sheet motors and the sunroof motors of hybrid or electric vehicles, due to their excellent magnetic properties. Microstructural alignment of HDDR treated powders are mostly depending on the hydrogen reaction in disproportionation step, so the specific method to control hydrogenation reaction is required for improving magnetic properties. In disproportionation step, hydrogenation pressure and reaction time were controlled in the range of 0.15~1.0 atm for 15~180 min in order to control the micorstructural alignment of $Nd_2Fe_{14}B$ phase and, at the same time, to improve remanence of HDDR treated magnet powders. In this study, we could obtain a well aligned anisotropic Nd-Fe-B-Ga-Nb alloy powder having high remanence of 12 kG by reducing hydrogen pressure down to 0.3 atm in disproportionation step.

Prediction of Wave Energy Absorption Efficiency and Wave Loads of a Three-Dimensional Bottom-Mounted OWC Wave Power Device (착저식 OWC 파력발전장치의 파에너지 흡수효율 및 파랑하중 계산)

  • Hong, Do-Chun;Hong, Key-Yong
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.13 no.1
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    • pp.47-52
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    • 2010
  • The wave energy absorption efficiency and the first-order and the time-mean second-order wave loads of a three-dimensional bottom-mounted oscillating water column (OWC) chamber structure are studied. The potential problem is solved by making use of a hybrid Green integral equation associated with the finite-waterdepth free-surface Green function outside a twin chamber and the Rankine Green function inside taking account of the fluctuating air pressure inside the chamber. Numerical results of the primary wave energy converting efficiency and the oscillating and steady wave loads of a three-dimensional bottom-mounted OWC pilot plant have been presented.

Thermal Analysis of Water Cooled ISG Based on a Thermal Equivalent Circuit Network

  • Kim, Kyu-Seob;Lee, Byeong-Hwa;Jung, Jae-Woo;Hong, Jung-Pyo
    • Journal of Electrical Engineering and Technology
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    • v.9 no.3
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    • pp.893-898
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    • 2014
  • Recently, the interior permanent synchronous motor (IPMSM) has been applied to an integrated starter and generator (ISG) for hybrid electric vehicles. In the design of such a motor, thermal analysis is necessary to maximize the power density because the loss is proportional to the power of a motor. Therefore, a cooling device as a heat sink is required internally. Generally, a cooling system designed with a water jacket structure is widely used for electric motors because it has advantages of simple structure and cooling effectiveness. An effective approach to analyze an electric machine with a water jacket is a thermal equivalent network. This network is composed of thermal resistance, a heat source, and thermal capacitance that consider the conduction, convection, and radiation. In particular, modeling of the cooling channel in a network is challenging owing to the flow of the coolant. In this paper, temperature prediction using a thermal equivalent network is performed in an ISG that has a water cooled system. Then, an experiment is conducted to verify the thermal equivalent network.

Study of the Reduction of Torque Ripples for Multi-pole Interior Permanent Magnet Synchronous Motors using Rotor Saliency (회전자 돌극 설계를 이용한 다극 매입형 영구자석 동기전동기의 토크리플 저감 연구)

  • Kim, Ki-Chan
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.10
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    • pp.6270-6275
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    • 2014
  • The paper reports an improvement method on torque ripples of multi-pole interior permanent magnet synchronous motor (IPMSM) applied to a traction motor for hybrid electric vehicles. In the case of multi-pole IPMSM, the magnetic flux generated by a permanent magnet tends to leak through the bridge of the rotor without a link with stator windings. The slit design on the rotor surface was proposed to reduce torque rippling and increase the output power by reducing the leakage flux. Two design parameters for the slit are suggested for optimal design using the response surface method. As an analysis method, the 2D finite element method (FEM) was applied to consider magnetic saturation effect.

A Study on Driving Simulation and Efficiency Maps with Nonlinear IPMSM Datasets

  • Kim, Won-Ho;Jang, Ik-Sang;Lee, Ki-Doek;Im, Jong-Bin;Jin, Chang-Sung;Koo, Dae-Hyun;Lee, Ju
    • Journal of Magnetics
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    • v.16 no.1
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    • pp.71-73
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    • 2011
  • Hybrid electric vehicles have attracted much attention of late, emphasizing the necessity of developing traction motors with a high input current and a wide speed range. Among such traction motors, various researches have been conducted on interior permanent-magnet synchronous motors (IPMSMs) with high power density and mechanical solidity. Due to the complexity of its parameters, however, with nonlinear motor characteristics and current vector control, it is actually difficult to accurately estimate the base speed within an actual operating speed range or a voltage limit. Moreover, it is impossible to construct an efficiency map as the efficiency differs according to the control mode. In this study, a simulation method for operation performance considering the nonlinearity of IPMSM was proposed. For this, datasets of various nonlinear parameters were made via the finite-element method and interpolation. Maximum torque-per-ampere and flux-weakening control were accurately simulated using the datasets, and an IPMSM efficiency map was accurately constructed based on the simulation. Lastly, the validity of the simulation was verified through tests.

Inner Temperature Distribution by Two Appearances of Series-Cell Configured Battery Pack using Cylindrical Cells (원통형셀 기반 직렬배터리팩의 외형(정사/직사면체) 차이에 의한 내부 열분포 기초해석)

  • Han, Dong-Ho;Lee, Pyeng-Yeon;Park, Jin-Hyeng;Kim, Jonghoon;Yoo, Kisoo;Cho, In-Ho
    • The Transactions of the Korean Institute of Power Electronics
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    • v.23 no.6
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    • pp.408-414
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    • 2018
  • Given that lithium-ion batteries are expected to be used as power sources for electric and hybrid vehicles, thermodynamics experimentation and prediction based on experimental data were performed. Thermal, electrochemical, and electrochemical/electrical-thermal models were used for accurate battery modeling. Various applications of different battery packs were demonstrated, and thermal analysis was performed using the same experimental conditions for square and rectangular battery packs. Accurate thermal analysis for a single cell should be prioritized to determine the thermal behavior of the battery pack. The energy balance equation, which contains heat generation and heat transfer factors, defines the thermal behavior of the battery pack. By comparing battery packs of different shapes tested under the same condition, this study revealed that the rectangular battery pack is superior to the square battery pack in terms of the maximum temperature of inner cells and temperature variation between cells.