Research On Accurate Modeling And Control System Of A Flywheel Motor Considering Vehicle Start-Up Driving Conditions

At present,electric vehicles generally use chemical battery as a power battery,but the chemical battery’s short life,low efficiency,serious pollution and other shortcomings restrict its development.The magnetic levitation flywheel battery has a broad application prospect in the field of electric vehicles due to its characteristics of no pollution,high energy conversion rate and long service life.For the vehicle-mounted maglev flywheel battery,the vehicle driving condition is the disturbance factor that cannot be ignored,among which the vehicle starting condition is the most basic vehicle driving condition.Flywheel motor is the key component of energy conversion of vehicle maglev flywheel battery.Due to the influence of vehicle starting condition,the flywheel rotor is easily disturbed to make the flywheel motor eccentric,resulting in the deterioration of its performance,which further affects the performance of the magnetic suspension support system.Therefore,an accurate model of the flywheel motor considering the starting condition of the vehicle is proposed and controlled in this dissertation,in order to help improve the anti-disturbance ability of the maglev support system and improve the stability of the vehicle-mounted maglev flywheel battery.This dissertation takes the flywheel motor for the virtual axle type vehicle maglev flywheel battery as the research object.The main work is as follows:1.The research background of flywheel battery is summarized,and the working principle of flywheel battery,key technologies and technical requirements of flywheel motor are outlined.The development of eccentric motor modeling and brushless DC motor direct torque control are described.The research significance and work arrangement of this dissertation are summarized.2.Taking two typical vehicle starting conditions as examples,the influence of the performance of the flywheel motor and the movement trajectory of the flywheel rotor are analyzed.The procedure of calculating inductance of motor by Modified Winding Function Approach(MWFA)is summarized.It is found that the geometric derivation method of air gap function is not suitable for modeling of vehicle starting condition.In this dissertation,a scheme is proposed to predict the air gap function of flywheel motor based on vehicle starting condition and to build a flywheel motor model considering vehicle starting condition by using MWFA.3.The Direct Torque Control(DTC)of the flywheel motor is studied based on the precise model of the flywheel motor considering the vehicle starting condition.The model of flux and torque observation is established,and it is found that flux can be controlled by torque.Therefore,a scheme of observing electromagnetic torque by Hall logic signal is proposed,and the control system is simplified by ignoring the observation of flux.The automatic control of flux chain is verified by a series of simulations.4.The static simulation platform of vehicle driving condition and dynamic simulation platform of vehicle driving condition are established,and the hardware and software of the control system are introduced.The simulation test of vehicle starting condition is designed.The results show that the flywheel motor model has higher accuracy and the performance of magnetic suspension support system has been improved obviously.