A non-contact measuring method for the joint size and geometry irregularity of Halbach permanent magnet guideway in the high-temperature superconducting maglev system

As an essential part of high -temperature superconducting (HTS) magnetic levitation, the irregularity of the permanent magnetic guideway (PMG) affects the safe and stable operation of the vehicle. However, measuring the geometric irregularity and the joint size is difficult because of the existing PMG surface covering protection and iron filings. To solve this problem, first of all, based on the equivalent surface current method, the magnetic field above the PMG is calculated when considering the geometric irregularities in Shanghai high-speed Maglev Demonstration Line. Next, a non -contact method for measuring the joint width, lateral dislocations, and height difference of PMG is proposed based on the sinusoidal magnetic field above PMG. Furthermore, the conversion method of magnetic irregularity to geometric irregularity is proposed, and we can get the magnetic field irregularity at any point in space. The measuring method can be applied to the rapid non -contact detection of PMGs in large quantities.