Design And Multi Physical Field Analysis Of High Speed Permanent Magnet Motor For Flywheel Energy Storage

As an energy storage technology,flywheel energy storage has many advantages,such as high energy density,high charging and discharging frequency,long service life,energy saving and environmental protection.As the core of electromechanical energy conversion,high-speed motor and flywheel rotor are very important.The flywheel rotor is the key to improve the energy storage density of the system.The performance of high-speed motor is directly related to the performance of the entire flywheel energy storage system.In this paper,the flywheel energy storage system with the radial integration of the flywheel rotor and the outer rotor of the high-speed motor is studied.A high-speed permanent magnet motor with 350 k W and 36000 r/min composite magnetic particle fiber structure is designed.The research of high-speed permanent magnet motor for flywheel energy storage is carried out from the perspective of multi physical field.According to the particularity of the motor,the influence of composite magnetic fiber material on electromagnetic characteristics is analyzed;In the temperature analysis,the influence of thermal radiation on the motor in vacuum is considered;In mechanical analysis,the equivalent method of mechanical properties of composite fiber materials is specially considered.and a multi-objective optimization design method based on high speed motor is given in this paper.The main research contents are as follows:Firstly,the particularity of the external rotor high-speed permanent magnet motor is described,the influence of composite magnetic fiber material on the electromagnetic performance is analyzed,and the preliminary design of the motor is completed,and the multiphysical field design process of the motor is given.Secondly,the type of loss of high-speed permanent magnet motor for flywheel energy storage is analyzed.The thermal network method and computational fluid dynamics method are used to calculate and compare the temperature rise respectively.Since the distribution environment is vacuum,the influence of thermal radiation is considered in this paper.The influence of the type of medium and the velocity of the cooling system on the cooling capacity of the motor is analyzed.In addition,in order to ensure the safe operation of the motor at high speed,the motor is calculated and checked from the mechanical point of view.In terms of the motor stress,the analytical calculation formula of the rotor stress of the outer rotor in the high-speed motor is given,the performance of the composite magnetic fiber material is predicted,and the influence of the key parameters such as the amount of interference and the speed on the stress distribution is analyzed.In rotor dynamics,the influence of key parameters such as damping,stiffness,rotor length and AMB length on rotor resonance are analyzed.Finally,a multi-objective optimization method based on electromagnetic characteristics is proposed.On the basis of the stress and dynamics analysis of the motor,the parameters of the main components are limited.Based on the electromagnetic characteristics of multi-objective optimization,was realized using the algorithm of the NSGA-Ⅱ motor.Combined with the response surface method,through the finite element analysis software ANSYS,the simulation optimization analysis was carried out,high efficiency and low thermal load and motor performance is proved from the Angle of the finite element.