Design and experimental research on a new type of convergent hybrid magnet for magnetic levitation belt conveyor

Aiming at the problems of magnetic leakage and high energy consumption of conventional electro-magnet-permanent magnet hybrid magnet structure, a new type of convergent hybrid magnet which is suitable for the supporting system of magnetic levitation belt conveyor was proposed on the basis of E-type electromagnet.Based on the operation mechanism of the magnetic suspension belt conveyor, a new type of circular convergent magnet was introduced to improve the magnetic circuit by analyzing the magnetic flux leakage path of the E-type hybrid magnet.On the foundation of Maxwell's electromagnetics theory, combined with magnetic circuit method, integral method and regional division method, the magnetic flux paths of the converged magnet were divided.Also, the analytical expressions of the magnetic flux paths of each part were established.The influence of the structure of the convergent magnet on the magnetic flux was further studied, and three different magnetic flux loops were found with the change of the convergent magnet structure.The existence conditions and magnetic circuit conditions under the three kinds of magnetic flux were discussed in detail, and the general analytical expressions of electromagnetic force and magnetic flux leakage coefficient were obtained.Furthermore, the accuracy of the theoretical analysis was verified by experiment.Combined with Maxwell electromagnetic field finite element software and Simulink dynamic system model, the static and dynamic characteristics of hybrid magnet were analyzed.The results show that compared with hybrid magnet before improvement, the convergent hybrid magnet hybrid magnet reduced the flux leakage by about 20% and increased the flux density by about 10% under large air gap which improve the distribution of magnetic circuit.At the same time, the convergent hybrid magnet had a higher suspension stiffness and damping that could realize stable suspension quicker.On the purpose of improved magnet efficiency and reducing the cost of materials, the influences of the axial length and magnetization thickness of convergent hybrid magnet on the magnetic flux leakage coefficient were analyzed.It was found that the magnetic flux leakage increased with the increase of magnetization thickness, and the axial length had little influence on the magnetic flux leakage, except when the convergent hybrid magnet was used to change the flux loop.Furthermore, the genetic algorithm was used in Matlab to optimize the structure size of the convergent magnet.After iterative calculation, the optimal convergent magnet axial length and magnetization thickness were both 5 mm.