Modelling and Analysis of Double-Layer Harmonic Linear Generator for Superconducting Electrodynamic Suspension Integrated with Propulsion, Levitation and Guidance

As one of the most potential maglev technologies to break the speed limit of rail transit, superconducting electrodynamic suspension (EDS) avoids the contact between wheel-rail and pantograph-catenary by means of electromagnetic interactions. Since electrical power can not be transmitted directly from the ground to onboard equipment, contactless linear generator is critical for the superconducting EDS train, which is basically achieved through the onboard power collection coils. However, the structure of existing power collection coil can only use the fifth harmonic magnetic field excited by the ground coil, but other order harmonic components are hard to employ. In order to solve this problem, a linear generator with double-layer power collection coil is proposed, aiming at propulsion, levitation and guidance (PLG) coil on the track where harmonic magnetic field is more complex. A significant advantage is that the proposed structure can adopt both the second and fifth harmonic magnetic fields, thereby increasing the utilization rate of harmonic energy. Firstly, the magnetic field distribution is deeply analyzed via Biot-Savart law for different topologies of EDS system. Secondly, an electromagnetic model of harmonic linear generator is built through analytical equations, and validated by finite element model. Finally, according to main harmonic orders, the structure parameters of double-layer power collection coil is confirmed and analyzed, which provides design scheme and technical reference for the contactless power supply technology of superconducting EDS train.