Design Study Of The High Temperature Superconducting Linear Induction Motor

Compared with the rotating induction motor, the linear induction motor has many advantages, such as:the low noise, the climbing ability, the non-adhesive drive and the small radius through curves. But the low efficiency and the low power factor restrict its development. With the advances in the high-temperature superconducting (HTS) materials, the high-temperature superconducting linear induction motor (HTS LIM) could be achieved. And it provides a new idea to improve the efficiency of the linear induction motor. This dissertation focuses on the working principle, structure design, magnetic circuit analysis, parametric analysis, loss and efficiency analysis, the influence of the structural parameters on the motor performance, control systems, manufacturing and testing of the prototype. The main text is as follows:The characteristics of the HTS winding coils are analyzed. And its AC loss is tested. Based on the three phase AC current of the HTS LIM primary windings, combined with the distribution of the motor flux lines obtained from the Maxwell finite element electromagnetic simulation, the magnetic polarity of the motor primary windings, the direction of the secondary plate current, the x-axis component and the y-axis component of the air gap magnetic field are analyzed in detail. The thrust and the normal force of the motor are analyzed when the motor is in the motor state, in the power state and in the electromagnetic brake state. The influence of the longitudinal end effect and the transverse end effect on the motor performance are analyzed.The Maxwell2D finite element electromagnetic simulation method of the HTS LIM is described. From the motor design specifications and the electromagnetic load, the relationship between the electromagnetic load and the main motor size is analyzed. And the method of determing the main motor size and the parameters is also analyzed. The pole number, slot number, primary windings and core parameters are obtained.According to the primary winding parameters of the HTS LIM, the size of the HTS winding coils is calculated in detail. And the primary winding pattern of the HTS LIM is studied. The critical current of the HTS winding coils is affected by the background vertical magnetic field. The influence of the slot height and the slot blank width on the internal magnetic flux density of the primary windings is focused. And this will be the basis of the primary core size. Two different cooling systems are analyzed. The structure and the size of the cooling system used in this issue are analyzed in detail. Combined with the Maxwell finite element electromagnetic simulation results, the magnetic circuit of the HTS LIM is analyzed in detail. As the special structure of the HTS LIM, the calculation factor of the magnetic circuit for the traditional induction motor is no longer suitable for the HTS LIM. The pole arc coefficient, the air-gap magnetic form factor and the gas gap coefficient are devided and analyzed. The motor air gap magnetomotive, the tooth magnetomotive and the yoke magnetomotive are calculated. The induced electromotive force and the magnetomotive of the HTS LIM are analyzed in detail. The magnetic circuit calculation value and the finite element simulation value of the excitation current for the HTS LIM are compared and analyzed.The main reactor and the primary leakage reactor of the HTS LIM are analyzed and calculated. The slot leakage reactance, the harmonic leakage reactance and the end leakage reactance are focused. The equivalent circuit and the vector diagram of the HTS LIM are studied. The three-phase winding current, the thrust force, the vertical force, the motor speed and the motor position in the load condition are analyzed. The losses of the HTS LIM include the basic iron loss, the electrical loss, the mechanical loss and the stray loss. The basic iron loss and the copper loss of the secondary plate are calculated. And based on the electrical parameters of the Guangzhou Metro Line4, the efficiency rate of the HTS LIM compared to the traditional linear induction motor is calculated.The influence of the structural parameters on the performance of the HTS LIM is great. In both cases of the constant voltage and the constant current the motor structural parameters are studied, including:primary winding turns, the primary core shape (slot height, slot blank width, tooth width), primary core width, secondary plate size and air gap length. The motor performance includes:the motor thrust, the normal force, the primary winding current and the power factor.The basic principles, the hardware configuration and the software design of the linear traction platform are analyzed. The rotor field oriented vector control algorithm using single neuron PID controller is focused. Combined with the particularity of the HTS LIM equivalent circuit parameters, the test method of separating the primary leakage reactance and the main reactance of the motor is studied. According to the no-load test results and the locked rotor test results, the equivalent circuit parameters of the prototype motor with copper windings are obtained. Through comparing the load test results and the Maxwell electromagnetic finite element simulation results of the prototype motor with copper windings, the correction factor kFx is obtained that is used to correct the electromagnetic thrust of the Maxwell2D finite element simulation. According to the zero-state current response of the RL series circuit, the starting current characteristics of the HTS LIM are analyzed. The load tests of the HTS LIM are completed and the test results show that the design and the manufacture of the HTS LIM meet the design specifications.Finally, through the study of the magnetic circuit, the electrical circuit and the performance of the HTS LIM, the design theory and the analysis method of the HTS LIM are set. According to the manufacture and the test of the prototype motor with copper windings and the HTS LIM, the accuracy of these theories and methods are validated. And it has a good reference value for the design and the application of the HTS LIM.