Multi-objective Optimization Design Of Vehicle-mounted Magnetic Suspension Flywheel Battery With Virtual Inertia Spindle

Virtual shaft flywheel battery has high integration,superior energy storage and strong anti-interference ability,so it is especially suitable for vehicle-mounted occasions with high space restrictions and whose stability is seriously affected by vehicle conditions.It is worth noting that,due to the particularity of the flywheel battery topology,which should be considered in the design of integrated energy storage characteristics and performance index of the mutual restriction relation between anti-interference characteristics,so how to coordinate the relationship of the three performance indicators is designed,the key to the flywheel battery system of motor magnetic suspension bearing flywheel battery system The flywheel rotor three key components of design is good or bad or not directly determine whether the flywheel battery system meet the performance requirements Therefore,based on a virtual shaft flywheel battery as the research object,mainly used for the permanent magnet synchronous motor and magnetic levitation bearing flywheel rotor system for initial design and the multi-objective optimization design,designed to meet the vehicle flywheel battery system in integration Requirements for stable suspension and energy storage characteristicsThe main work and innovation of this paper are as follows:1.This paper describes the research background,working principle and key technology of flywheel battery for electric vehicle,analyzes the significance and necessity of multi-objective optimization design of flywheel battery by analyzing the development of flywheel battery topology,and introduces the current research status of multi-objective optimization method.2.The initial design of virtual axle vehicle flywheel battery system is carried out.Motor: Considering that the motor is embedded at the bottom of the metal flywheel,the motor adopts more rotor polar logarithms to improve the torque density,and the co-simulation analysis method is used to analyze the torque performance of the motor in detail.Magnetic levitation abutter-flywheel rotor system: Considering integration and the anti-disturbance suspension performance,the magnetic circuit analysis of the combined magnetic bearing of the flywheel battery system was carried out.The suspension performance of the magnetic bearing was analyzed by using the finite element method,and the initial parameter design of the magnetic bearing was completed.Considering the energy storage characteristics,the stress analysis of the virtual shaft flywheel rotor was carried out,and the key energy storage performance parameters of the flywheel rotor were calculated3.Because PMSM adopts more polar logarithms,the flat top width of the back potential is reduced,and the torque ripple under brushless DC drive is increased In order to improve the torque performance of the motor,multi-objective hierarchical optimization design is adopted.Therefore,this paper innovatively proposes to divide the optimization objective into two priorities and divide the design variables At priority 1,with average torque and torque ripple as the optimization objectives,the torque performance of the motor was improved by combining the finite element surrogate model with the multi-objective genetic algorithm(MOGA-NSGA-II)In priority 2,in addition to considering average torque and torque ripple,the amount of permanent magnet is also taken as the optimization objective,which further improves the torque performance of the motor.In the whole optimization process,multi-objective hierarchical design can not only effectively divide the grades of optimization objectives,but also help to reduce the dimension of design space and improve the optimization efficiency4.Magnetic levitation abutter-flywheel rotor system adopts embedded structure,which limits the maximum suspension force of magnetic bearing and reduces the shape coefficient of flywheel rotor’s energy storage performance In order to improve suspension performance and energy storage performance,a multi-objective optimization method was adopted and multiple physical field constraints were considered.The electromagnetic finite element replacement model and stress finite element replacement model were established respectively with suspension force density and shape coefficient as optimization objectives Furthermore,combined with the multi-objective genetic algorithm(MOGA-NSGA-II),the suspension performance and energy storage performance of the magnetic levitation abutment-flywheel rotor system are improved.