Design of an Axial-Type Magnetic Gear for the Contact-Less Recharging of a Heavy-Duty Bus Flywheel Storage System

Forces in Axial Flux Magnetic Gears with Integer and Fractional Gear Ratios

“…Despite their very similar designs, the AFMG models considered in the paper differ in one relevant aspect, which is the gear ratio. In spite of a relatively small difference in the mentioned gear ratio, significant changes in the torque characteristics ( Figure 3a) are observed, which are also mentioned by other authors [12,24]. An over fourfold increase in magnetic torque pulsation for MG1 significantly affects the ergonomics of the gear, which is magnetically balanced in theory.…”

“…All of these works [3][4][5][6][7][8][9][10][11][12] are consistent when it comes to the limitations caused by axial forces. They point to the need to reduce axial forces and to ensure appropriate gear rigidity as early as at the design phase, also taking the bearing arrangement into account.…”

“…However, this always involves a reduction of the torque transferred. This Section is inspired by the paper [12], wherein the use of AFMGs for energy transfer in the context of FESS application was discussed. When analyzing the available literature, no detailed description of the methods for selecting the width of the air gap from the point of view of axial force and shaft load was found.…”

“…For AFMGs, if the radius increases, volumetric torque density (VTD) increases much faster, with a similar value of PM gravimetric torque density (PM GTD) as compared to RFMGs [10]. In addition to these indicators, the possibility/susceptibility of building multi-level structures, the easier hermetic sealing of elements due to the arrangement of flat discs, and the relatively low sensitivity to air gap width were also noticed in the context of the application of flywheel energy storage systems (FESS) [12]. Undoubtedly, the potential of using AFMGs in contactless charging systems for public transport vehicles is a perfect addition to the modern trends of progressing urbanization combined with environmental protection, in terms of clean air.…”

Average power balance method for power failure compensation control of high‐speed turbo molecular pump with AMB system

“…With the rapid development of active magnetic bearing (AMB) technology, more and more high-speed permanent magnet (PM) electric machines adopted AMB system because of its microvibration, no lubrication and long life [1][2][3][4][5][6]. Electric machine with AMB can realise the high power density for the industrial highspeed equipment such as control moment gyroscope [7], magnetically suspended flywheel [8] and vacuum turbo molecular pump (TMP) [9]. However, in actual application, the main power failure always happens, and the high-speed AMB rotor without the suspension force will crash the stator elements chaotically due to the serious gyroscopic effect [10,11].…”