Study On The Superconducting Linear Synchronous Drive Technology

The linear drive motor has promising application in all sorts of machines that require linear motion. A disadvantage of the linear motor is low efficiency and resultant high-temperature rise in itself because of the resistance of the stator coil and low current density of the coil. The problem can be solved partly through the application of superconducting technology. Firstly, ohmic loss of the linear motor can be reduced largely because of zero resistance of superconductor. Secondary, the current density of the superconductor is about100-1000times than the copper. So the application of superconducting magnet in linear drive motor can produce higher magnetic field and higher thrust force, and also reduce the volume and weight of the linear motor system. Accordingly, the application of the superconducting technology will promote the fast development of linear drive technology.Firstly, the paper theoretically analyzes the principle of both DC current and pulsed current superconducting linear synchronous drive system. Based on the theoretical analysis of superconducting linear synchronous drive system principle, this paper completed the design research of DC superconducting linear synchronous drive system. By using PSIM, Quartus II, Ansoft and other simulation software, the circuit, control system and moving process of armature were simulated and analyzed respectively. According to the optimization of the system design results, a DC low temperature superconducting linear synchronous drive system consisting of two superconducting stator coil was established. Comparing the experimental results and the theoretical design values, the correctness of the design and the feasibility of superconducting linear drive technology were proved.Meanwhile, this paper analyses and simulates the subsystems of pulsed-current superconducting linear driving system. The simulation results show that the critical problem of the optimal design is how to match between current waveform of stator coil and mutual-inductance grads to achieve the best performance. Different system parameters can realize different linear driving functions. For example, different trigger positions can realize stepping function with different steps, and straight line motion with different running speed.The high temperature superconducting (HTS) stator coils of pulsed current superconducting linear driving system should experience a pulsed current which is higher than the critical current of HTS tapes. The superconducting stator coil which withstands such an impact of current pulse (without damage) is related to the safety and reliability of the pulsed current superconducting linear driving system. So over-current testing of the HTS coil is performed in the last part of the paper. Experimental results show that the HTS superconducting coil can withstand a short over-current pulse which is6times than the critical current of HTS tapes without being damaged electromechanically, and the quench area can revert to superconducting state quickly after the current decayed. The over-current impact ability of HTS coil proves the feasibility of pulsed current HTS linear driving technology.