Electromagnetic Analysis And Optimization Design Of Superconducting Linear Motor For Electromagnetic Launch

With the development of the economy and the need to maintain national security,the requirements for maneuverability and controllability in the start-up process of modern fighter jets or reconnaissance aircraft in the military field are also increasing.Among various aircraft take-off methods,the electromagnetic ejection system has the advantages of high exit speed,good controllability,and short preparation period compared with traditional hydraulic and pneumatic ejection methods.It is the most advantageous of the existing take-off methods.As the core part of the electromagnetic ejection system,the linear motor directly provides thrust to the ejection target.However,compared with the superconducting linear motor,the traditional normal-conducting linear motor has some disadvantages,such as smaller thrust density and larger weight,which limit the efficiency of the electromagnetic ejection system.In this paper,a double-sided superconducting synchronous linear motor for electromagnetic ejection is designed,and the rationality of the design is verified by simulation results.Compared with the characteristics of different take-off modes of the aircraft,the electromagnetic ejection mode has obvious advantages.Introduced the development history of electromagnetic ejection technology and superconducting technology,summarized the research status of different types of linear motors used in electromagnetic ejection,compared and analyzed the characteristics of different types of motors.The analysis shows that the superconducting linear motor has higher thrust densityThe design of superconducting linear synchronous motor for electromagnetic catapult is completed by referring to the design method of traditional rotating motor.The overall topology of the motor adopts the form of a moving magnet and double-sided stator linear synchronous motor,and the main size of the motor is determined according to the design specifications and the selected electric load and magnetic load.Taking into account the strong magnetic field characteristics of superconducting magnets,the stator adopts a coreless structure.Taking into account the versatility and maintenance of the system,the stator winding adopts a simple structure of concentrated winding,and further completes the modular and segmented design of the stator winding.Completed the design of the superconducting mover,including the selection of superconducting magnet material,the design of superconducting magnet size and the design of cryogenic vessel.The superconducting mover magnet is designed in detail,and the magnetic field strength on different sections of the superconducting magnet is analyzed to ensure that the magnetic field of the superconducting magnet does not exceed its critical magnetic field during operation.According to the characteristics of superconducting materials,the establishment of the simulation model of superconducting linear motor is completed,and the performance parameters such as thrust change,magnetic field distribution,back EMF and loss during the acceleration and deceleration of the motor are verified and analyzed through finite element simulation.The electromagnetic properties of stator without core are compared with that of stator with core,and the advantages of stator without core are verified.Compared with the permanent magnet synchronous linear motor of the same size,it is verified that the superconducting linear motor has higher thrust density.Furthermore,the transient conditions of the motor’s starting process are simulated and calculated,and the no-load starting characteristics at different starting frequencies and the load starting characteristics under different load forces are analyzed.Finally,the influence of different structural parameters on the performance of linear motor is studied.The performances of the motor with different stator back iron thickness,air gap,primary current,pole distance and different superconducting magnet width is analyzed,including air gap magnetic field,steady thrust,thrust fluctuation,core loss and other performance parameters.According to the analysis results,the optimization scheme of superconducting linear motor is given.The optimized motor can generate more thrust while keeping the number of ampere-turns of the superconducting magnet coil constant.