1、1The Matching Design of Electric VehiclesMotor DriveAbstract. Motor matching is critical to dynamic of electric vehicles. Through theoretical calculation and engineering analysis， this paper discussed about the motor， and the transmission ratio， confirmed the selection method of the working conditio
2、n and continuous working condition rated parameters of electric vehicle motors， set an example of calculation parameters， drew the motor torque characteristics picture， and lays the foundation for the production and selection of motors. Keywords： Electric Vehicle； Power System； Electrical Characteri
3、stics； Constant Power And Constant Torque 1. Introduction The power system of electric vehicles mainly comprises four parts of motor， power battery， drive system and control system. Electric vehicle power matching task is to satisfy the basic requirements of vehicle dynamic performance on the reason
4、able selection of dynamic parameters for parts assembly， wherein the motor design matching is improve transmission 2efficiency and meet important link certain mileage. 2. The parameter matching of motors The motor is the only source of pure electric vehicles， which is closely related to its performa
5、nce and dynamic performance of electric vehicle. 2.1 The choice of the type of drive motor Motor for electric vehicles can be divided into two categories， namely， a commutator motor and brushless motor. The former said that they usually have commutator assembly， while the latter without commutator a
6、ssembly. Mainly have the following several kinds of motor type； a DC motor commutator； no induction motor commutator of DC motors， permanent magnet motor， switched reluctance motor. 2.2 The matching of the motor peak power and rated power The power of the motor size is directly related to power elec
7、tric cars are good or bad. The motor power is greater， the acceleration and the maximum grade is better， but the volume and quality of motor will accordingly increase， at the same time， the motor can not keep working in high efficiency， reduce the electric vehicle energy utilization rate， reduces th
8、e automobile mileage.The calculation formulas are as follows： 32.3 Motor speed and rated speed selection and matching The selection of the conventional speed nb and the highest speed nmax should be consistent with the requirements of the driving motor torque speed characteristics， as shown in figure
9、 1. The 2.5 To determine the motor short constant torque motor maximum speed The motor working condition to start and when climbing continuously accelerated to （u=20 25km/h） corresponding speed is appropriate， according to the determined （ ）： 3. The parameters of transmission design The parameters o
10、f transmission of electric vehicle matching design include： transmission ratio of gear and determination of the main reducer transmission ratio design. The motor output properties， dynamic indices of transmission ratio selection depends on the vehicle requirements， if the fixed transmission ratio tr
11、ansmission system can not meet the maximum speed requirements， should consider the need to determine the transmission minimum transmission ratio and the maximum transmission ratio of two file two file transmission， or above. 3.1 The minimum transmission ratio transmission system 4（9） Formula： motor
12、maximum speed， r/min； - electric vehicle maximum speed， km/h. 3.2 To determine the ratio of the maximum transmission 3.2.1 To determine the maximum transmission ratio by Max gradient and maximum output torque （10） Formula： -motor maximum output torque； N ? M. General electric cars should have 30% cl
13、imbing ability. 3.2.2 Maximum transmission ratio is determined by the maximum speed of the motor torque （11） Formula： - air resistance maximum speed electric car， N； - The output torque of the maximum speed of correspondingmotor， N ? M. The maximum transmission ratio is the larger one of ， so that i
14、t can meet the requirements of driving force. 4. Examplesof analysis and calculation In pure electric vehicles to be developed as an example， according to the requirements of the basic parameters and performance of it （see Table 1 and table 4） based on the principle of calculation， the parameters th
15、at determine the 5performance of electric vehicles， and as a reference for selecting the motor. 5. Conclusion 5.1 Draw the motor torque characteristics Motor drive system is the core of pure electric vehicle components， so the selection of the motor is very important. Because of the constant torque
16、speed and constant power characteristics， and general motors in the medium speed （motor rated speed） ， the efficiency and power factor of low torque range is relatively high， so the conventional speed of vehicles is often on the base speed， while the maximum speed is on the power line. To calculate
17、the performance parameters of the motor according to the above method， characteristic should have plotted curve in motor vehicle （see Figure 2） ， which can be used in the production of motor or preliminary quickly select motor， and then according to the actual performance of the motor selection， we
18、can determine the actual vehicle maximum speed， maximum grad ability and acceleration etc. Fig. 2 Schematic diagram of motor torque characteristics 5.2 Design and application of motor characteristics meet the basic principle of electric vehicle performance 6The performance of the motor is divided in
19、to continuous working performance and working performance. The continuous working characteristic curve is determined by motor ratings. Short-time working curve is the torque characteristic curve after a certain number of overloads motors. By the formula （1） （11） calculated parameters，we can accurate
20、ly determine the parameters of dynamic performance of electric vehicles： 1） The highest speed calculation for electric vehicles is calculated by the rated power of the motor； 2） The max gradient of maximum torque is calculated by short work of motor vehicles； 3） The conventional speed of electric ca
21、rs should fall on the motor of the baseband frequency （40 50km/h） ； 4） Electric vehicle maximum speed power balance point should fall on the continuous working performance curve in the motor power section. References 1 Mingjie Xiong， Guoqiang Hu， Fujian and Jianping. Pure Electric Vehicle Power Syst
22、em Parameter Selection and Matching. Automotive Engineering， 2011 （5）： 36-37 2 Jinfeng Yu. A Preliminary Study on Power Electric 7Vehicle（D）. Luoyang： Henan University of Science and Technology Vehicle and Power Engineering College， 2003 3 Jifen Zhu， Feng Gao， Rong Zhou. Study on the parameter match
23、ing of transmission system of pure electric vehicles J. automobile technology， 2005 （6）： 23-28 4 Mingjie Xiong， Guoqiang Hu， Jianping Min. Pure electric vehicle power system parameter selection and matching. Automotive engineering， 2011 （5） 5 Minqiang Hu， Xueliang Huang. Method and application of nu
24、merical calculation of motor performance. Southeast University press， 2003.11 6 Shuxian Wang， Chunan Deng. Study on Motor for Electric Vehicle Technology. Micro Motor， 2006 eighth 7 Zhisheng Yu. The automobile theory third edition. Beijing Machinery Industry Press， 2000.10 8 Zheng Li， Rong Zhou. Ele
25、ctric Vehicle Drive Motor Vehicle tTchnology 2007.3 selection method 9 Bing Deng， Junmin Pan. Simulation of Non Computer Brush DC Motor Control system. Computer simulation， 2002.5 10 Gang Liu， Zhiqiang Wang， Jiancheng Fang. Permanent Magnet Brushless DC Motor Control Technology and Application. The Mechanical Industry Press， 2008. 5
