Research On Structural Variation Of New Type High-temperature Superconducting Direct Current Generator

The successful development of high-temperature superconducting materials has made the working temperature requirement of superconducting equipment increase from liquid helium temperature zone to liquid nitrogen temperature zone,which greatly broadens the scope of application of superconducting technology.With the preparation technology of high-temperature superconducting materials and the accompanying cooling technology becoming more and more mature,the application of high-temperature superconducting in the field of electric motors is more and more extensive.At present,the main obstacle to the development of high-temperature superconducting machines is the quenching problem that may be caused by the AC loss inside the motor.In this paper,a new type of high-temperature super-superconducting DC generator with no AC loss is studied.The structural variation and optimization are carried out according to the design index and the output characteristics of the generator.The effects of different variation structures of the generator on the magnetic field distribution and output of the motor are studied.And design the cooling system of the motor to study the effect of the cooling structure on the electromagnetic field and temperature field distribution inside the motor.Firstly,the electromagnetic properties of superconducting materials are studied.According to the theoretical basis of finite element calculation and the heat transfer theory inside the motor,the electromagnetic field and temperature field of the motor are studied.The basic structure and working principle of superconducting DC motor are analyzed.The source of AC losses in superconducting machines and a summary of conventional solutions to reduce AC losses.Secondly,the structure of the new high-temperature fully superconducting DC generator is proposed.The rationality of the structure of the motor is theoretically analyzed.The new structure motor is designed with reference to the design flow of the superconducting single-pole DC motor,mainly including the design of the motor size and the material of each part of the motor.Selecting and selecting the key components of the motor,using the finite element simulation software to simulate the reasonable structure and main parameters of the motor,the simulation verified that the motor is a DC motor without AC loss.Thirdly,the variation of the structure of the motor is studied for the defects of the originally designed motor.The variation structure of the double-layer permanent magnet is used to increase the size of the air gap magnetic field.The variation structure of the double-layer squirrel cage armature is used to improve the low voltage and high current of the motor.Characteristics,including the selection of magnetic shielding methods and materials,and the influence of the thickness of the shielding layer on the shielding results,using the magnetic structure of the stator core without magnetic permeability to reduce the volume and weight of the motor,and based on the magnetic induction at the air gap The size of the motor optimizes the parameters of the excitation and armature sections of the motor.Finally,the cooling system of the new high-temperature fully superconducting DC generator is designed.The Dewar structure is modeled,its influence on the magnetic field is analyzed,the thermal conductivity of each part of the motor is calculated,and the heat source of the motor body is analyzed.The two-dimensional temperature field model of the motor is established,and the temperature field distribution of the motor is simulated and analyzed.