Active magnetic bearings for energy storage systems for combat vehicles

Abstract

Abstract--To minimize CHPS flywheel size and mass, a topology was chosen in which the rotating portion of the flywheel is located outside the stationary components. Accordingly, magnetic bearing actuators are required which share this "inside-out" configuration. Because of inherent low loss and nearly linear force characteristics, UT-CEM has designed and analyzed permanent magnet bias bearing actuators for this application. To verify actuator performance, a non-rotating bearing test fixture was designed and built which permits measurement of static and dynamic force. An active magnetic bearing (AMB) control system was designed to provide robust, efficient magnetic levitation of the CHPS rotor over a wide range of operating speeds and disturbance inputs, while minimizing the occurrence of backup bearing touchdowns. This paper discusses bearing system requirements, actuator and controller design, and predicted performance; it also compares theoretical vs. measured actuator characteristics. Manuscript

Outer-rotor ac homopolar motors for flywheel energy storage

“…With these design choices, combined with the amount of energy to be stored in the flywheel, the following approach can be used to dimension the machine. The homopolar flux density B f 0 is calculated from B max andB f 1 for a square rotor in (8). The minimum airgap flux density (9), the required field winding ampereturns (10), the axial length needed for the field winding (11), and the maximum airgap length (12) can then be calculated.…”

“…Previous work has concluded that bearing loss can be substantially reduced by using carefully designed magnetic bearings [8] and that frictional windage loss can be nearly eliminated by using a vacuum of approximately 1mTorr [9]. The magnetic losses associated with the motor depend on the type of motor chosen.…”

Modeling for Three-Pole Radial Hybrid Magnetic Bearing Considering Edge Effect

“…Due to the advantages of high speed, no friction, high precision and long service life [1][2][3][4][5], magnetic bearings play an important role in electric drives working under high speed, vacuum and clean conditions. They have been applied in rotating machinery applications like motorized spindles, agile satellites and flywheel systems [6][7][8][9][10][11][12]. The most common configurations for radial magnetic bearings are eight-pole type and four-pole type [13].…”

Lumped-Parameter Model to Describe Dynamic Translational Interaction for High-Temperature Superconducting Bearings

“…Along with vertical lifting capability, the lateral stiffness affects dynamic performance and may limit operation. For applications such as flywheel energy storage, operation above critical speed may be required to meet energy storage requirements [4]. The low lateral stiffness and damping capabilities of HTSC bearings have been shown to impede operations above critical speeds [5].…”