Research On Key Technologies Of High Temperature Superconducting Armature Winding Motor

The high temperature superconductor(HTS)material,with the advantages of high current-carrying capability and low loss,could be widely applied in strong electricity field.The conventional motor designs and optimization methods are not easy to improve the limited performance further since the maturity of the motor technology.An effective way to break through the barrier of the motor torque and power density is to adopt new materials,such as superconducting materials.The critical current is used to measure the current carrying capacity of high temperature superconductors.Based on the theory of flux dynamics,this paper analyzes the critical state and mechanism of high temperature superconductivity.Through the critical current measurement of many HTS tapes,the relationship between the critical current and magnetic field under DC and AC condition was studied.This paper made use of the COMSOL finite element software to establish the runway type HTS coil mfh model and PDE model.The consistency of the calculation results of the two models is verified by the calculation of the AC loss of the high temperature superconducting strip.Several key issues involved in the establ ishment of the coil model are discussed.In this paper,the voltage distribution and critical current of each part of the runway type coil were calculated by using the established finite element model of the HTS coil.The calculation results are consisten t with the measurement results.The critical current determination method of HTS coil proposed above was verified.In this paper,the finite element model of the HTS coil under the external magnetic field was established,which provided a theoretical basis for the later the calculation of the current carrying characteristics of the superconducting windings in the stator core.In this paper,the distribution of the electric field intensity E,the current density J and the magnetic induction B of the high temperature superconducting coil were studied in detail by measuring the voltage of each part of the high temperature superconducting coil and combining the finite element calculation results.And a method for measuring and determining the critical current of high temperature superconducting coil was proposed.This paper carried out study on electrical measurement method of HTS.B,established the HTS tape and coil test system based on Labview and virtual instrument to realize the functions of automatic curren t loading and automatic data storage,which improved the measurement efficiency and convenience.By writing the Labview programs,using the NI board to establish a time-sharing multi-channel measurement system and virtual lock-in amplifier to meet the measurement requirements.In this paper,the key problems involved in the formation of windings were studied.Firstly,the influence of the welding form and the length of the solder joint on the resistance and the critical current of the high-temperature superconducting tape was studied by experiment.Thus to make a suggestion for the winding form of double pancake superconducting coil and the end winding scheme of superconducting winding.In this paper,the leakage current field in the motor slot was calculated,and the critical current of the high temperature superconducting winding was calculated by combining the finite element model of the high temperature superconducting coil.The calculation results are consistent with the measurement results.In this paper,the over current of superconducting winding in stator core was measured,and the degree of attenuation of current carrying capacity of superconducting windings under the action of leakage magnetic field in the slot was studied.The AC loss limits the high speed application of the HTS winding motor.In this paper,a brushless double-fed motor form(hereafter referred to as HTS brushless doubly-fed motor)of HTS mixed with constant conduction was proposed,to achieve high speed in the case of superconducting winding transmission of DC current or low frequency AC current,so as to ensure that the AC loss is controlled in a certain range.In this paper,the finite element model of the motor was established.The performance parameters and loss of the motor were calculated.The advantages of the motor in the power density were analyzed,and a test prototype was developed and carried out test to verify the design and calculation results.In this paper,the HTS brushless doubly fed motor form is an effective way to realize high speed of HTS armature winding motor is proved by measuring the critical current characteristics of HTS tapes under different frequency alternating field.In summary,this paper took the HTS armature winding motor as the main object of study,studied the key technology and the key problem of the two generation HTS belt material used in motor armature winding.Based on the basic electromagnetic properties of the superconducting material to study the characteristics of critical current of HTS materials,we carried out study on the calculation method of electromagnetic characteristics of HTS coils,and established finite element model of two kinds of HTS coil.The critical current characteristics of high temperature superconducting materials are studied,and a method for measuring and determining the critical current of high temperature superconducting coils is proposed.The measurement results verified the calculation results.The key issues involved in HTS windings were studied,which provided a theoretical basis for the design of superconducting windings in engineering practice.A new type of HTS brushless doubly fed machine was proposed,which provided a new approach and thought for realizing high speed of HTS armature winding motor.