• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.4
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• pp.555-566
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• 2012

This paper presents a thermal analysis of an interior PM synchronous machine with concentrated winding for electric vehicle. The conventional thermal equivalent network model has been used for a long time for calculation of the temperature rises in electrical machines. In spite of being popular, this method can not be applied correctly for elements with complicated cooling structure like liquid cooled housing. To overcome this drawbacks, in this paper, a hybrid thermal model using the result of CFD analysis partly. Using this method, to improve a thermal performance of PMSM with concentrated winding, the effects of two design parameters are analysed. Finally, the accuracy of this model has been verified by experiments for the developed 21kW motor.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.123-124
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• 2015

본 논문에서는 동기전동기(PMSM: Permanent Magnet Synchronous Motor)의 고정자 형상 변화를 통한 코깅토크(Cogging Torque)와 토크리플(Torque Ripple)저감에 대해 다루고자 한다. 고정자의 치의 두께와 길이에 변화를 주면서 FEM(Finite Elements Method)기반의 성능분석을 실시하여 각 형태에 대한 평균토크, 토크리플, 코깅토크를 분석, 비교해보았다.

• The Transactions of the Korean Institute of Power Electronics
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• v.22 no.5
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• pp.397-403
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• 2017

This paper studies the voltage angle control of interior permanent magnet synchronous motors (IPMSMs). For voltage angle control, the optimum voltage angle trajectory according to the operating speed is researched while the voltage and current limit conditions are considered. Through research, two different optimum voltage angle trajectories that depend on the design of IPMSMs were found. The IPMSM drive based on a voltage angle control that follows such trajectory is proposed. Unlike the conventional voltage angle control method, which is applied only in the flux-weakening region, the proposed voltage angle control can be implemented in all operation ranges from low to high speed. The proposed method is verified by experiments using a DSC controller for 800 W IPMSM.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.3
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• pp.73-82
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• 2011

Most of countries start to restrict the emission gases of vehicles especially CO2 because of the global warming. Many vehicle companies including Toyota have launched various HEVs to satisfy the restriction laws and to improve the vehicle's efficiency. However, development for heavy-duty hybrid system is not plentiful rather than the passenger car. In this study, we choose the optimal size of engine, motor and battery for heavy-duty hybrid systems using dynamic programming. Also we analyze the correlation of the system's cost and efficiency because the added cost of vehicle to make the hybrid system is very important factor for the manufacturing companies. Finally, this study suggests a method to choose the appropriate system components size considering its performance and the cost. With this method, it is possible to select the component size for various systems.

• Proceedings of the KIEE Conference
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• 2004.04a
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• pp.266-268
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• 2004

In this study, on-line measuring system were developed to verify performances and functions of traction system that are used in KTX(Korea Train eXpress) synthetically and efficiently, and have been measuring electric signals of vehicle as well as mechanical signals up to the present. Running-braking measuring equipment was constructed in vehicle to optimize signal acquisition and analysis ability of the measuring system. Measurement data of signal were performed acquisition, analysis and evaluation using this equipment. KRRI(Korea Railroad Research Institute) described about main specifications of measuring equipment. Also, the structure and principles as well as main circuit system were explained in brief. KRRI analyzed the characteristics comparing design values with experimental values about running distance, running time and positive acceleration for KTX is running in full traction. We analyzed the distance and time according to number of motor block. In result, running characteristics of traction system in KTX were verified and could be evaluated.

• The Transactions of the Korean Institute of Power Electronics
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• v.27 no.1
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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.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.10
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• pp.911-920
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• 2016

For the pitch and yaw axis attitude control of launch vehicle, thrust vector control which changes the direction of thrust during the engine combustion is commonly used. Hydraulic actuation system has been used generally as a drive system for the thrust vector control of launch vehicles with the advantage of power-to-weight ratio. Nowadays, due to the developments of highly efficient electric motor and motor control techniques, it has done a lot of research to adopt electro-mechanical actuator for thrust vector control of small-sized launch vehicles. This paper describes system design and test results of the prototype of direct drive electro-mechanical actuation system which is being developed for the thrust vector control of $3^{rd}$ stage engine of KSVL-II.

• Journal of Power Electronics
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• v.11 no.2
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• pp.194-201
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• 2011

The air flow supplied to a fuel cell system is one of the most significant factors in determining fuel efficiency. The conventional method of controlling the air flow is to fix the oxygen supply at an estimated constant rate for optimal efficiency. However, the actual optimal point can deviated from the pre-set value due to temperature, load conditions and so on. In this paper, the maximum efficiency point tracking (MEPT) algorithm is proposed for finding the optimal air supply rate in real time to maximize the net-power generation of fuel cell systems. The fixed step MEPT algorithm has slow dynamics, thus it affects the overall efficiency. As a result, the variable step MEPT algorithm is proposed to compensate for this problem instead of a fixed one. The complete small signal model of a PEM Fuel cell system is developed to perform a stability analysis and to present a design guideline. For a design example, a 1kW PEM fuel cell system with a DSP 56F807 (Motorola Inc) was built and tested using the proposed MEPT algorithm. This control algorithm is very effective for a soft current change load like a grid connected system or a hybrid electric vehicle system with a secondary energy source.

• Journal of IKEEE
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• v.23 no.1
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• pp.261-265
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• 2019

We analyze the failure rate change of a conventional bidirectional converter and a modified one which moves an output capacitor towards propulsion battery. We analysis of the circuit structural homogeneity and the difference between both converters, and confirm that the capacitor working voltage is reduced by changing the capacitor position. After obtaining the capacitor failure rate according to voltage stress factor and operating temperature, it is applied to the fault-tree of the bidirectional converter to obtain the overall failure rate of the converter. We analyzes the advantages and disadvantages of design changes by comparing and analyzing the failure rate and mean time between failures (MTBF) according to operating temperature and capacitance value.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.11a
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• pp.313-318
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• 2007

Interior permanent magnet synchronous motor(IPMSM) has become a popular choice in electric vehicle applications, due to their excellent power to weight ratio. This paper proposes maximum torque control of IPMSM drive using adaptive fuzzy neural network controller and artificial neural network(ANN). This control method is applicable over the entire speed range which considered the limits of the inverter's current and voltage rated value. For each control mode, a condition that determines the optimal d-axis current $i_d$ for maximum torque operation is derived. This paper considers the design and implementation of novel technique of high performance speed control for IPMSM using Adaptive-FNN controller and ANN controller. The hybrid combination of neural network and fuzzy control will produce a powerful representation flexibility and numerical processing capability. Also, this paper reposes speed control of IPMSM using Adaptive-FNN and estimation of speed using ANN controller. The back propagation neural network technique is used to provide a real time adaptive estimation of the motor speed. The proposed control algorithm is a lied to IPMSM drive system controlled Adaptive-FNN and ANN controller, the operating characteristics controlled by maximum torque control are examined in detail. Also, this paper proposes the analysis results to verify the effectiveness of the Adaptive-FNN and ANN controller.