Modulation Concepts for the Control of a Two-Phase Bearingless Slice Motor Utilizing Three-Phase Power Modules (original) (raw)

Comparison of winding concepts for bearingless pumps

Bearingless slice motors as employed in semiconductor, pharmaceutical and medical industry perform magnetic levitation by radial bearing forces and rotation by tangential forces. This requires bearing and drive windings, which can be realized as separate bearing and drive coils or as identical, concentrated coils on the stator claws. In this paper, a detailed comparison between these two winding concepts is undertaken, where the coil losses, the coil volume, the power electronics requirements and the achievable rotation speed are evaluated. Furthermore, practical features such as control complexity, cabling effort and manufacturability are taken into account. Finally, the trade-off between losses, volume and realization effort will be discussed in order to give a guideline for the selection of the appropriate winding concept for a specific application of a bearingless pump.

A Novel Driving Scheme for Three-Phase Bearingless Induction Machine with Split Winding

Energies, 2021

In order to reduce the costs of implementing the radial position control system of a three-phase bearingless machine with split winding, this article proposes a driving method that uses only two phases of the system instead of the three-phase traditional one. It reduces from six to four the number of inverter legs, drivers, sensors, and current controllers necessary to drive and control the system. To justify the proposal, this new power and control configuration was applied to a 250 W machine controlled by a digital signal processor (DSP). The results obtained demonstrated that it is possible to carry out the radial position control through two phases, without loss of performance in relation to the conventional three-phase drive and control system.