In-wheel Motor Electric Vehicle Research Articles

Analyze for Vertical Vibration of the In-Wheel Motor Electric Vehicle Based on Power Flow Method

The vertical vibration of the in-wheel motor electric vehicle (IWM-EV) induced by large unsprung mass is analyzed based on power flow method. The simulation results show that due to the unsprung mass increase of IWM-EV, energy consumption of the suspension and wheel is increasing, which will cause adverse effects on not just the ride comfort but the maneuver stability. To decrease the effect, a new kind of vibration mitigation measure of the vehicle body absorber combined with an active hybrid control integrated the sky-hook and ground-hook methods is developed. The effectiveness of this measure is verified.

Actuator-Redundancy-Based Fault Diagnosis for Four-Wheel Independently Actuated Electric Vehicles

This paper presents a real-time actuator-redundancy-based fault diagnosis approach for four-wheel independently actuated (FWIA) in-wheel motor electric ground vehicles. The tire-road friction coefficient (TRFC), which is usually unknown, needs to be accurately estimated to calculate the in-wheel motor torque and evaluate the fault in real time. An observer is applied to each of the in-wheel motors to generate a TRFC estimate from the respective wheel. The individual estimates of the TRFC are merged using a voting scheme, which can reject the erroneous estimate from the faulty motor. Then, the resulting accurate TRFC estimate is adopted to calculate the residual for each of the in-wheel motors and to detect the possible actuator fault. Experimental results from a prototype FWIA electric ground vehicle are given to show the effectiveness of the proposed fault diagnosis method.

Design of Efficient In-Wheel Motor for Electric Vehicles

This research paper deals with the design and development of an in-wheel motor for electric vehicles. The proposed motor generates a 350-watt power drive with a power source of two 12V batteries. The batteries are connected in series to increase the voltage to 24 volts and 18.23 A. The in-wheel motor is based on the principle of a DC electric motor to drive the vehicle wheels so that the mechanical components of the transmission and the energy loss are minimized. The proposed in-wheel motor has 46 poles, 51 slots and 51 teeth. In addition, the method lowers the maintenance cost. This research work assumes the maximum weight of 70kg and the running speed of 20km/hr. The experiment results show that the output power and efficiency of the in-wheel motor are subject to the variation in input power given that the input voltage remains constant at 25.41 volts. The maximum efficiency of the in-wheel motor of 82.56% is achieved at 2.5 N-m torque. The maximum torque of 6.25 N-m is achieved with the input power of 348.76 watts.

Integrated Slip-Based Torque Control of Antilock Braking System for In-Wheel Motor Electric Vehicle

Integrated Slip-Based Torque Control of Antilock Braking System for In-Wheel Motor Electric Vehicle

Developing Simulation Model for Four In-Wheel Motor Electric Vehicle Based on Simulink

The 15 DOF four in-wheel motor electric vehicle model is developed based on Matlab / Simulink. The model adopts modular design. The dynamic model equations, vehicle model diagram and the methods of each module modeling are presented. The model is verified by commercial software Carsim. The results show that the model is higher accuracy and it can be used for the control algorithm improvements and validation as a good platform.

Cooling performance of 25 kW in-wheel motor for electric vehicles

The in-wheel motor used in electric vehicles was designed and constructed for an electric direct-drive traction system. It is difficult to connect cooling water piping to the in-wheel motor because the in-wheel motor is located within the wheel structure. In the air cooling structure for the in-wheel motor, an 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 for various motor speeds and heat generations. In order to resolve 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). The thermo-flow analysis of the in-wheel motor for vehicles was performed in consideration of ram air effect. Also, in order to improve cooling effect of the motor, we variously changed geometries of housing. Therefore, we confirmed the feasibility of the air cooling for the motors of 25 kW capacity with housing geometry having cooling grooves and investigated the cooling performance enhancement. We found that the cooling effect was most excellent, in case that cooling groove direction was same with air flow direction and arranged densely.

A novel direct yaw moment controller for in-wheel motor electric vehicles

A novel direct yaw moment controller is developed in this paper. A hierarchical control architecture is adopted in the controller design. In the upper controller, a driver model and a vehicle model are used to obtain the driver's intention and the vehicle states, respectively. The upper controller determines the desired yaw moment by means of sliding mode control. The lower controller distributes differential longitudinal forces according to the desired yaw moment. A nonlinear tyre model, ‘UniTire’, is utilised to develop the novel distribution strategy and the control boundary.

Technical Potential of In-Wheel Motors for Electric Vehicles

Technical Potential of In-Wheel Motors for Electric Vehicles

Analytical analysis and implementation of a low-speed high-torque permanent magnet vernier in-wheel motor for electric vehicle

In this paper, analytical analysis of the permanent magnet vernier (PMV) is presented. The key is to analytically solve the governing Laplacian/quasi-Poissonian field equations in the motor regions. By using the time-stepping finite element method, the analytical method is verified. Hence, the performances of the PMV machine are quantitatively compared with that of the analytical results. The analytical results agree well with the finite element method results. Finally, the experimental results are given to further show the validity of the analysis.

The Present Status and Future Trends of In-Wheel Motors for Electric Vehicles

In-wheel motor drive has been developed quickly. In this paper, the characteristics of four traditional machines are first reviewed and evaluated. Then, the present status of in-wheel motor drive are discussed, finally, future research trends of electrical machines in EVs are described.

Analysis on cogging torque of driving in-wheel motor for electric vehicle

In order to reduce the torque fluctuation, vibration and acoustic noise of driving in–wheel motor for electric vehicle, this paper researches the generation mechanism and influence factors of cogging torque. Based on energy method and Fourier expansion, an analytical method is proposed to establish the expression of cogging torque, which can express its relation with design parameters. Based on the expression, the match of pole and slot, pole arc coefficient and permanent magnet eccentric distance are analysed and studied. Ansoft software is used to establish a time–varying movement electromagnetic field finite element model, which can compute the cogging torque about the different match of the pole and slot, different pole arc coefficient and different permanent magnet eccentric distance, in order to obtain the change regularity of the corresponding cogging torque. The conformity of the final simulation computation results with the theoretical analysis indicates this method can be used to provide a theoretical basis to make further optimal design of the new driving in–wheel motor and its control system, so as to reduce torque ripple of in–wheel motor.

Development of traction control for front-wheel drive in-wheel motor electric vehicles

This paper proposes a novel traction control for a front–wheel drive in–wheel motor electric vehicle. The presented vehicle has advantages on high fuel efficiency and cost effectiveness. In order to achieve specific control performance, this study employed a high speed microcontroller as the vehicle's electronic control unit. The anti–skid function based on a reliable traction control kernel is embedded in the system, which can guarantee the steering safety in a slippery and dangerous situation. This study verifies that the traction control based on maximum torque regulation cannot only constrain the slip to improve the longitudinal friction force and lateral friction force, but also provide some information on tyre–road conditions, which can ensure the performance and the effectiveness of two–dimensional motion control. The numerical simulation and demonstration video reveal its effectiveness and feasibility.

Vehicle Dynamics Control of In-wheel Electric Motor Drive Vehicles Based on Averaging of Tire Force Usage

For in-wheel electric motor drive vehicles, a new vehicle dynamics control which is based on the tire force usage rate is proposed. The new controller adopts non-linear optimal control could manage the interference between direct yaw-moment control and the tire force usage rate. The new control is considered total longitudinal and transverse tire force. Therefore the controller can prevent tire force saturation near tire force limit during cornering. Simulations and test runs by the custom made four wheel drive in-wheel motor electric vehicle show that higher driving stability performance compared to the performance of the same vehicle without control.

Calculation of Characteristics of Axial-Gap Motor with Skew Based on Analysis with Three-dimensional Reluctance Network

Axial-gap motors have higher torque density than those with conventional radial gaps because they are able to reduce the thickness of the motor and increase the number of poles with a relatively smaller radius. Therefore, axial-gap motors are expected to be applied to various fields such as home electrical appliances and the in-wheel motors for electric vehicles. The establishment of an optimal method of design for axial-gap motors is required, but it generally takes a long time to calculate the characteristics of these motors since it is necessary to analyze the three-dimensional electromagnetic field. To overcome this problem, this paper presents a method of calculating the characteristics of axial-gap motors with skew based on reluctance network analysis (RNA). The validity of the proposed method is tested and proved by comparing the measurements with the results from finite element method (FEM) analysis.

1107 タイヤ稼働率を用いた電気自動車の車両運動制御の研究(OS3-2 車両運動制御,OS3 交通・物流システムの制御,オーガナイズド・セッション)

We propose new vehicle dynamics management of in-wheel electric motor vehicle based on tire force usage rate. In the vehicle dynamics management, we adopted non-linear optimizing controller using direct yaw-moment control, tire force usage rate and each tire force. In cornering performance test simulation of 3 degree freedom model, we confirmed that by using this vehicle dynamics management, saturating tire force could be avoided and higher critical speed also could be achieved. We did the simulation and the run test by the in-wheel electric motor vehicle. By these simulation and run test, it was confirmed that the 4 wheel drive in-wheel motor electric vehicle with the proposed vehicle dynamics management system could have higher stability performance comparing to the same vehicle without control.

Vehicle Dynamics Management of Electric Vehicle Based on Tire Force Usage (1st Report, Examination of Tire Force Usage Control for In Wheel Motors)

We propose new vehicle dynamics management of in-wheel electric motor vehicle based on tire force usage rate. In the vehicle dynamics management, we adopted non-linear optimizing controller using direct yaw-moment control, tire force usage rate and each tire force. In cornering performance test simulation of 3 degree freedom model, we confirmed that by using this vehicle dynamics management, saturating tire force could be avoided and higher critical speed also could be achieved. We also conducted pylon course slalom test simulation. By this simulation, it was confirmed that the 4 wheel drive in-wheel motor electric vehicle with the proposed vehicle dynamics management system could have higher stability performance comparing to the same vehicle without control.