| The appearance of electrical vehicle(EV)has realized the long-term expectation for zero emission of vehicle.The transmission system is the key part of the vehicle,whose technical innovation is the only way which must be passed for EV development.Considering the features of pure electrical power output of the EV,to create a transmission system which could use direct-drive AMT can help improve efficiency of the transmission system and lower the energy loss during shifting process,which can further enhance the shifting power performance and driving range.Based on the research results from international and domestic learners,this thesis came up a series of structure scheme about transmission system using direct-drive AMT.Matched the high efficiency transmission ratio and the parameters of the electric vehicle power system,calculated the vehicle's equivalent moment of inertia,and designed a general test bench which could be used for shift test researching of EV.Conducted the simulation research of speed regulation shift of direct-drive AMT and speed regulation shift of motor based on MATLAB/Simulink,and the two synchronization methods have been compared and analyzed by using electromagnetic linear actuator speed regulate and motor speed regulate during the synchronous phase of shifting process,which provides a theoretical basis for the technical progress of automatic transmission.The specific contents were shown below:(1)Firstly,the selecting and matching of power system based on the requirements of EV design has been processed,finishing the selection of the main reducer,transmission gears number and transmission ratio.In order to guarantee the motor works in high efficient area when the vehicle runs in normal speed,a method has been presented which is to calculate the high efficiency transmission ratio of the transmission system based on normal running speed and driving motor high efficient speed area,so that the motor efficiency improved and driving range increased.(2)The general test bench has been designed which is used for shift performance test research of EV transmission using direct-drive AMT,which can simulate the vehicle's equivalent moment of inertia within 9-14 kg·m2,and be utilized for the shifting test by different types of family cars.In order to simulate the inertia of the vehicle on the bench,the vehicle's equivalent moment of inertia is calculated.The mechanical inertia simulation device used by the bench can avoid the turbo lag effect when using electrical inertia simulation methods.The vehicle's equivalent moment of inertia have been simulated separately,which can improve the bench simulate accuracy of the transient conditions.(3)The segmentation research of AMT shifting process has been done after the analysis of shift principle of transmission,and the clear dynamic models of shifting process has been set up.Deriving the mathematical model of permanent magnet synchronous motor in different coordinate systems,using the motor space vector control strategy of the speed and current double closed loop,establishing the mathematical model of the motor speed regulation system.(4)Simulation research for the performance of shift actuator was conducted based on MATLAB/Simulink,and studied the effects of main design and control parameters on AMT shift actuator.Based on motor mathematical model and its control strategy,a PMSM vector control system of speed regulate simulation model has been built based on MATLAB/Simulink.The special features of two synchronization methods have been compared and analyzed by using electromagnetic linear actuator speed regulate and motor speed regulate during the synchronous phase of shifting process.The simulation results show that,in the synchronous phase of shifting process,the motor speed regulation time will be 0.03 s shorter than the electromagnetic linear actuator under the condition of same rotating speed difference,but the speed regulation energy consumption of motor is nearly 10 times than the electromagnetic linear actuator. |
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