Experimental test bench for electrodynamic levitation system characterization

In recent years, globalisation and the focus on climate issues have led several governments to invest in faster, safer, and less polluting transport systems. Hyperloop Transportation Technology stands at the centre of this scenario due to its ability to reach very high speeds by exploiting electrodynamic phenomena between the track and the magnets attached to the train capsule. One of the most important factors on which the feasibility of the project depends, and on which most contemporary studies are focusing, is the stability of the system. State of art literature has shown that the unstable nature of magnetic levitation systems depends on the strong interaction between the electrodynamic and mechanical domains. This instability can be identified using a lumped-parameter model with multiple branches and can be removed by adding damping through a secondary suspension. Another important aspect is to analyse how the lift and drag forces to which the magnetic levitation system is subjected vary according to the speed and distance between the track and the magnets. After a brief literature review, to validate electrodynamic levitation, a dedicated test bench is proposed: some of its elements, such as load cells, aluminum track and copper rim, are characterized and the procedure followed to create a 90° Halbach array is illustrated. Afterwards, the thesis is divided into two main parts: the first one concentrates on the quasi-static experiment and the lift and drag curves to which the 90° Halbach array is subject are analysed for different gaps and angular velocities of the test bench. In the second part, starting from the experimental data, using a multidomain approach and performing the root locus, an optimal value of damping necessary to stabilise the system is found. Subsequently, the use of a voice coil as a damper is justified and an attempt is made to characterise its most important quantities such as resistance, inductance, and intrinsic damping, which do not remain linear during its operation time. Finally, two possible control solutions that could be implemented on a dedicated control unit and on the test bench are illustrated.