• Journal of Electrical Engineering and Technology
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• 제12권6호
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• pp.2307-2316
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• 2017

The aim of this paper is to provide an optimal design of in-wheel motor for an electric scooter (E-scooter) considering economical production. The preliminary development in-wheel motor, which has a direct-driven outer rotor type attached to the E-scooter's rear wheel without any gear, is introduced first. The objective of the optimal design of this in-wheel motor is to improve the output characteristics of the motor and to have a stator form to facilitate automatic winding. Response surface methodology was used for the optimal design and 2-dimensional finite element method was used for electro-magnetic field analysis. Experimental results showed that the designed and fabricated in-wheel motor could satisfy the required specifications in terms of speed, power, efficiency, and cogging torque.

• 한국자동차공학회논문집
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• 제20권1호
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• pp.61-67
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• 2012

The in-wheel motor used in green car was designed and constructed for an electric direct-drive traction system. It is difficult to connect cooling water piping because the in-wheel motor is located within the wheel structure. In the air cooling structure for the in-wheel motor, a outer surface on the housing is provided with cooling grooves to increase the heat transfer area. In this study, we carried out the analysis on the fluid flow and thermal characteristics of the in-wheel motor under the effects of motor speed and heat generation. In order to check the problem of heat release, the analysis has been performed using conjugate heat transfer (conduction and convection). As a result, flow fields and temperature distribution inside the in-wheel motor were obtained for base speed condition (1250 rpm) and maximum speed condition (5000 rpm). Also, the thermo-flow characteristics analysis of in-wheel motor for vehicles was performed in consideration of ram air effect. Therefore, we checked the feasibility of the air cooling for the housing geometry having cooling grooves and investigated the cooling performance enhancement.

• 전력전자학회논문지
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• 제15권6호
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• pp.498-505
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• 2010

In-Wheel System은 고성능의 전기모터를 Wheel에 직접 장착하여 파워트레인 요소를 모두 제거함으로써 차량시스템의 효율을 높인 시스템이다. 추후 친환경 차량에 적용할 수 있는 신개념의 플랫폼을 제공할 수 있는 고효율, 고성능 차량 시스템이기에 다양한 분야에 적용되고 있다. 이러한 시스템의 급증은 우리 생활의 안전과 직결되므로 개발단계에서 부품의 신뢰성을 확인하고 인증하여야 한다. 신뢰성이란 "부품이나 시스템이 주어진 환경에서 고장 없이 일정기간 동안 요구기능을 수행하는 특성"이다. 따라서 본 논문에서는 In-Wheel System의 핵심 부품인 In-Wheel Motor를 신뢰성 평가 중 하나인 내구 수명에 대한 검증 방안을 In-Wheel Motor의 운전 조건으로부터 가감속 토크 및 실효토크를 계산해서 이를 바탕으로 가속수명시험을 위한 속도 패턴을 제안하여 시험시간을 단축하고, 또한 In-Wheel Motor의 수명 신뢰성을 검증한다.

• 한국자동차공학회논문집
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• 제21권1호
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• pp.36-42
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• 2013

Recently, the automobile of the future will be able to substitute an electric vehicle for an internal combustion engine, so the following research is actively in the process of advancing. A traction motor is one of the core parts which compose the electric vehicle. Especially, it is difficult to connect cooling water piping to an in-wheel motor because the in-wheel motor is located within the wheel structure. This structure has disadvantage for closed type and air cooling, so the cooling design of motor housing and internal in-wheel motor is important. In this study, thermo-flow analysis of the in-wheel motor for vehicles was performed in consideration of ram air effect. In order to improve cooling efficiency of the motor, we variously changed geometries of housing and internal shape. As a result, we found that the cooling efficiency was most excellent, in case the cooling groove direction was same with air flow direction and arranged densely. Furthermore, we investigated the cooling performance enhancement with respect to variable geometries of internal in-wheel motor.

• 전기학회논문지
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• 제62권6호
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• pp.750-755
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• 2013

In-wheel motor system gets the driving force from direct-driven motor in the wheel of electric vehicle. It is known as good system for vehicles, from an efficiency, packaging, handling and safety. This paper describes motor and inverter technologies, system configuration and control algorithms for in-wheel type electric vehicle. It is necessary to control on an interrelation perspective because this system drives two motors at same time. In system design, IPMSM(Interior Permanent Magnet Synchronous Motor) including a wide operating range and high-speed rpm is used and flux weakening control is performed in constant power range. Under the torque command from the host controller, auto control box, inverter's output torque is calculated with using torque estimation technique and applied to actual vehicle driving system. It is verified that the configuration and the algorithm are suitable for the in-wheel motor system.

• 한국자동차공학회논문집
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• 제24권4호
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• pp.439-446
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• 2016

An in-wheel motor vehicle is a type of car that is equipped with an electric motor for each wheel. It is possible to acquire vehicle stability through a seperate driving torque control per wheel, since it directly generates the driving torque via the wheel motors. However, the vehicle ride comfort and road holding performance worsen depending on the increase of the wheel weights. In order to compensate for the impaired performance, an integrated chassis control system of the rear in-wheel motor vehicle is proposed. The proposed integrated chassis control system is composed of a driving torque control system, a semi-active suspension system, and an ESC system. According to the vehicle dynamic simulation of an in-wheel motor vehicle equipped with the integrated chassis control system, it is found that the system can improve the driving stability, ride comfort, and driving efficiency of the in-wheel motor vehicle.

• Journal of Power Electronics
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• 제13권4호
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• pp.536-545
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• 2013

In this study, an integrated motor control algorithm for an in-wheel electric vehicle is suggested. It consists of slip control that controls the in-wheel motor torque using the road friction coefficient and slip ratio; yaw rate control that controls the in-wheel motor torque according to the road friction coefficient and the yaw rate error; and velocity control that controls the vehicle velocity by a weight factor based on the road friction coefficient and the yaw rate error. A co-simulator was developed, which combined the vehicle performance simulator based on MATLAB/Simulink and the vehicle model of CarSim. Based on the co-simulator, a human-in-the-loop simulation environment was constructed, in which a driver can directly control the steering wheel, the accelerator pedal, and the brake pedal in real time. The performance of the integrated motor control algorithm for the in-wheel electric vehicle was evaluated through human-in-the-loop simulations.

• 한국자동차공학회논문집
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• 제22권5호
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• pp.29-34
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• 2014

Cooling the in-wheel motor in electric vehicles is critical to its performance and durability. In this study, thermal flow analysis was conducted by evaluating the thermal performance of two conventional cooling models for in-wheel motors under the continuous rating base speed condition. For conventional model #1, in which cooling oil was stagnant in the lower end of the motor, the maximum temperature of the coil was $221.7^{\circ}C$; for conventional model #2, in which cooling oil was circulated through the exit and entrance of the housing and jig, the maximum temperature of the coil was $155.4^{\circ}C$. Therefore, both models proved unsuitable for in-wheel motors since the motor control specifications limited the maximum temperature to $150^{\circ}C$.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2000년도 전력전자학술대회 논문집
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• pp.34-37
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• 2000

This paper presents the power compensation by wound-rotor induction motor with a Fly-wheel. In the wound-rotor induction motor the primary power is controlled by AC excitation which used the secondary power conversion. Based on theory this paper describes the dynamic response analysis of the would-rotor induction motor with Fly-wheel. Simulation and experimental results are performed to verify the proposed control method

• 전력전자학회:학술대회논문집
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• 전력전자학회 1999년도 전력전자학술대회 논문집
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• pp.535-539
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• 1999

This paper presents the 2nd excitation control of the wound-rotor induction motor with Fly-wheel. In the wound-rotor induction motor, the primary power is controlled by AC excitation which used the secondary power conversion. Based on theory, this paper describes the dynamic response analysis of the wound-rotor induction motor with Fly-wheel and Simulation using MATLAB is performed to verify the proposed control method.