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Li-Ye W.,CAS Institute of Electrical Engineering | Li-Ye W.,Beijing Co Innovation Center for Electrical Vehicles | Li-Fang W.,CAS Institute of Electrical Engineering | Li-Fang W.,Beijing Co Innovation Center for Electrical Vehicles | And 5 more authors.
2016 Asia-Pacific International Symposium on Electromagnetic Compatibility, APEMC 2016 | Year: 2016

In this paper, the principle of a Contactless Power Transfer (CPT) system is introduced, the situation of CPT system for electric vehicle about excessive startup current, coil short, system overheating and load open circuit are analyzed and research. According to the actual operating conditions of CPT system may exist fault, ready to power on protection strategy, the short circuit protection strategy, over heat protection strategy and open circuit protection strategy is presented. Experimental results show that these protection strategies are very important for the safety of CPT system. © 2016 IEEE.


Guo Y.,CAS Institute of Electrical Engineering | Guo Y.,Beijing Co Innovation Center for Electrical Vehicles | Wang L.,CAS Institute of Electrical Engineering | Wang L.,Beijing Co Innovation Center for Electrical Vehicles | And 3 more authors.
2016 Asia-Pacific International Symposium on Electromagnetic Compatibility, APEMC 2016 | Year: 2016

This paper presents an analysis of operation frequency and current effects on coil impedance and system characteristics of electric vehicle (EV) wireless charging system. Firstly, an equivalent circuit model of EV wireless charging system with dual side LCC compensation networks is established. Also, power loss and system efficiency expressions are given. Then, frequency influence is studied considering Litz wire used for the coils. Furthermore, effects of frequency and current are analyzed based on parameter measurements and tests. Finally, efficiency and output power change curves are given to show the impacts of frequency- and current-dependent coil impedances on system characteristics. © 2016 IEEE.


Chen D.,CAS Institute of Electrical Engineering | Wang L.,CAS Institute of Electrical Engineering | Wang L.,Beijing Co Innovation Center for Electrical Vehicles | Liao C.,CAS Institute of Electrical Engineering | And 5 more authors.
Diangong Jishu Xuebao/Transactions of China Electrotechnical Society | Year: 2015

In order to achieve a high efficiency, the wireless power transfer system(WPT) must operate at a high frequency. However serious eddy currents would be generated by the variable electromagnetic field in the ferromagnetic material around the WPT system. The power loss caused by the eddy currents in the chassis is analyzed by the finite element analysis and the equivalent circuit model is established with the influence of the chassis. At last, magnetic material is used to decrease the eddy current loss and different kinds of optimized magnetic structures are put forward. ©, 2015, The editorial office of Transaction of China Electrotechnical Society. All right reserved.


Zhu Q.,CAS Institute of Electrical Engineering | Chen D.,CAS Institute of Electrical Engineering | Wang L.,CAS Institute of Electrical Engineering | Wang L.,Beijing Co Innovation Center for Electrical Vehicles | And 4 more authors.
Diangong Jishu Xuebao/Transactions of China Electrotechnical Society | Year: 2015

With respect to wirelessly charging an electric vehicle (EV), the security issue caused by the inevitable electromagnetic radiation generated by the wireless charger greatly concerns the customers. In this paper, for a typical kilowatt-level magnetically resonant EV-oriented wireless charger, the magnetic field inside the electric vehicle and near the wireless charger is studied through circuit simulation and finite element analysis (FEA). Furthermore, the effectiveness of three shielding methods, i. e., completely shielding both the transmitter and the receiver, proposed horizontal or vertical shielding the outer transmitter, is compared. It shows that, radiation level inside the car is low since the vehicular chassis naturally provides an effective shielding; the proposed way of horizontally shielding the outer transmitter is very economic and effective to be applied on EV-oriented wireless charging systems. ©, 2015, The editorial office of Transaction of China Electrotechnical Society. All right reserved.


Liu M.-C.,Beijing Institute of Technology | Zhang C.-N.,Beijing Institute of Technology | Zhang C.-N.,Beijing Co innovation Center for Electrical Vehicles
International Journal of Vehicle Design | Year: 2015

This paper presents an optimal torque allocation control method for an individual eight-wheel-drive electric vehicle to improve longitudinal and lateral stability. The proposed optimal controller is designed as a hierarchical structure with an upper level controller and a lower level controller. The upper controller including human driver model is developed using sliding mode control algorithm, which takes longitudinal velocity, side slip angle and yaw rate as control variables. The lower controller is developed using optimal control algorithm, which optimally allocates the tractive/braking torque to eight in-wheel motors and mechanical brake system independently. Numerical simulation studies, including driver-vehicle-controller in-loop and open-loop simulations, are conducted to investigate the performance of the proposed controller. The simulation results show that the proposed controller significantly improves vehicle longitudinal and lateral stability. © 2015 Inderscience Enterprises Ltd.


Guo Y.,CAS Institute of Electrical Engineering | Guo Y.,Beijing Co Innovation Center for Electrical Vehicles | Wang L.,CAS Institute of Electrical Engineering | Wang L.,Beijing Co Innovation Center for Electrical Vehicles | And 5 more authors.
IEEE Transactions on Industrial Electronics | Year: 2016

This paper presents an equivalent model to analyze switch-on process of dynamic wireless charging system of electric vehicle (EV). In the model, system initial state before switching is considered and the full response is used to describe the switch-on process. First, the system states before and after switching are discussed, and an approximate method is proposed to calculate the initial value of converter dc-side voltage in switch-on unit. Then, equivalent transient sources and system transfer functions are obtained to establish the switch-on model. So, the switch-on process can be described through full responses of the selected currents under the excitation of equivalent sources. Furthermore, the proposed model is verified by a developed dynamic wireless EV charging prototype. Also, switch-on transient characteristics are investigated through discussions on system parameter and vehicle speed effects. Finally, a simple way to select the suitable switching position is provided based on the analysis of switching position influence, and its effectiveness has been validated by experimental results. © 1982-2012 IEEE.


Li S.,CAS Institute of Electrical Engineering | Liao C.,CAS Institute of Electrical Engineering | Liao C.,Beijing Co Innovation Center for Electrical Vehicles | Wang L.,Beijing Co Innovation Center for Electrical Vehicles | And 3 more authors.
Diangong Jishu Xuebao/Transactions of China Electrotechnical Society | Year: 2015

Wireless power transmission (WPT) technology is currently the cutting-edge technology in the field of power transmission, and the design of high quality factor coil is one of the key technologies of wireless power transmission. This paper firstly introduces several common wireless power transmission technologies, mainly focusing on the review of transmission methods, applying scope, basic principle and research methods of the magnetic coupling WPT system. Then, the optimized design of the coil in magnetic coupling WPT is elaborated, mainly in the following parts, the first part is the design of the coil's parameters, including the shape, structure, number of turns, the pitch of the coil turns, winding method, material selection, etc., the second part is the design of resonant link structure, such as the selection of 2 coils or 4 coils, the introduction of the intermediate coil, the use of ferrite, and the study of multi-transmitter coil and multi-receiver coil system. Finally, the experimental results are cited for the analysis and comparison of different kinds of coil designs. ©, 2015, The editorial office of Transaction of China Electrotechnical Society. All right reserved.


Zhai L.,Beijing Co Innovation Center for Electrical Vehicles | Zhai L.,Beijing Institute of Technology | Sun T.,Beijing Co Innovation Center for Electrical Vehicles | Sun T.,Beijing Institute of Technology | Wang J.,Foton Motor Inc.
IEEE Transactions on Vehicular Technology | Year: 2016

An electronic stability control (ESC) algorithm is proposed for a four in-wheel motor independent-drive electric vehicle (4MIDEV) utilizing motor driving and regenerative braking torque distribution control to improve vehicle stability. A stability judgment controller, an upper level controller, and a torque distribution algorithm are designed for the ESC system. The stability judgment controller is designed to generate the desired yaw rate and sideslip angle for vehicle stability, and the control mode, which is normal driving mode or ESC mode, is set according to the driver inputs and measurement signal inputs. The upper level controller consists of a speed tracking controller, a yaw moment controller, and four wheel-slip controllers to calculate the desired value of traction force, the desired value of yaw moment, and the four respective net torque inputs of the four in-wheel motors. The torque distribution algorithm is designed to generate each motor driving torque or regenerative braking torque input for each wheel. An average torque distribution strategy, a tire-dynamic-load-based torque distribution strategy, and a minimum-objective-function-based optimal torque distribution strategy are used separately in the torque distribution algorithm to control the motor driving torque or regenerative braking torque for vehicle stability enhancement. The proposed ESC algorithm was implemented and evaluated in a CarSim vehicle model and a MATLAB/Simulink control model. The three proposed torque distribution strategies can be used to regulate the vehicle to perform the following tasks: "single lane change," "double lane change," and "snake lane change." The simulation studies show that the yaw rate error root mean square [RMS (γ-γ-des)] decreased, on average, by 75 percent using the proposed optimal torque distribution algorithm compared with that without using stability control. © 2016 IEEE.


Li J.,CAS Institute of Electrical Engineering | Liao C.,CAS Institute of Electrical Engineering | Liao C.,Beijing Co Innovation Center for Electrical Vehicles | Wang L.,CAS Institute of Electrical Engineering | And 4 more authors.
Diangong Jishu Xuebao/Transactions of China Electrotechnical Society | Year: 2015

This paper develops a new wireless power transfer system circuit topology, containing LCCL impedance matching circuit in both primary and secondary sides. A new decoupling design method is proposed for circuit parameters to achieve both maximum and normal transferring power. Firstly, the maximum efficiency operation point is analyzed to get the circuit conditions. Secondly, the design method for LCCL impedance matching circuits in both primary and secondary is presented. System can achieve maximum efficiency operation by secondary side LCCL circuit, and meet the normal transferring power by primary side LCCL circuit. Lastly, an electric vehicle wireless charging system is established to verify the method. ©, 2015, The editorial office of Transaction of China Electrotechnical Society. All right reserved.


Guo Y.,CAS Institute of Electrical Engineering | Guo Y.,Beijing Co Innovation Center for Electrical Vehicles | Wang L.,CAS Institute of Electrical Engineering | Wang L.,Beijing Co Innovation Center for Electrical Vehicles | And 4 more authors.
Diangong Jishu Xuebao/Transactions of China Electrotechnical Society | Year: 2015

Electric vehicle (EV) wireless charging technology attracts more and more attentions because of its advantages of convenience, space-saving and no effect of bad weather, such as rain and snow. Firstly, model of four coil structure wireless charging system is established. Through the model, expressions of system output power and efficiency are calculated on the condition of non-sinusoidal input. Then, changing processes of output power and efficiency with frequency are discussed based on actual system parameters. Furthermore, effects of harmonics are analyzed and several results are obtained, for instance: the coil output power and efficiency will both reduce significantly when there are a large number of third order and fifth order harmonics in the input. Finally, characteristics of output power and efficiency in an actual EV wireless charging system are investigated through experiments. The experiments have verified the model and results in this paper. ©, 2015, The editorial office of Transaction of China Electrotechnical Society. All right reserved.

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