Research On Control Strategy Of Flywheel Auxiliary Power System For Electric Vehicle

The development of battery electric vehicles(BEV)must continue since this can lead us towards a zero emission transport system.However their low range and high cost still remain the two important drawbacks.There are various devices which could qualify as a secondary storage system for the BEV such as supercapacitor and flywheel.Thesis aims to research the electric vehicle flywheel auxiliary power system which is based on the traditional electric vehicle installed on the "electric type" flywheel auxiliary power unit,composed of a dual energy source,dual motor new power system.First of all,thesis analyzes the overall structure and working principle of electric vehicle flywheel auxiliary power system(EVFPS).The EVFPS integrates flywheel and control motor into vehicle power train via a planetary gear set and uses the differential characteristics of the planetary gear which implements electromechanical continuously variable transmission by an innovative system control strategy.And we can control the input and output energy of the flywheel as we want by adjusting the torque and speed of the control motor,which greatly improves the energy utilization of the electric vehicle.Secondly,according to the different driving conditions of the electric vehicle and the working principle of the flywheel auxiliary power system,the control strategy of the EVFPS is designed and developed,which mainly includes the driving control strategy and the braking energy recovery control strategy.The driving control strategy adopts the reference torque MAP and fuzzy control strategy,which can reasonably allocate the driving torque of the double motor.Braking energy recovery control strategy also uses fuzzy control strategy,which give full play to energy recovery efficiency.Thirdly,the vehicle dynamics model of the flywheel-assisted electric vehicle is established by AVL-CRUISE,and the vehicle driving control strategy and the braking energy recovery control strategy model is established by MATLAB / Simulink.Then this article combines CRUISE and Simulink vehicle simulation.The simulation results show that the control strategy can reasonably allocate the driving torque of the main drive motor and the control motor,and the power battery and flywheel can collect the braking energy when the vehicle is braking.Compared with the traditional electric vehicle,the recovery efficiency is greatly improved.Finally,a simple bench test of "electric type" flywheel auxiliary power system is carried out,which includes communication test,control motor characteristic test,flywheel start and release function characteristic test and system durability test.Thesis studies the flywheel auxiliary power system of electric vehicle by means of theoretical analysis,modeling and simulation and bench test.The simulation results verify that the control strategy designed in this paper can achieve better control effect.The bench test verifies the basic working characteristics of the system.For the flywheel in the application of electric vehicles has important guiding significance.