Analysis and control of one-axis active magnetic bearing using single side electromagnetic drive

Turbo molecular pumps (TMPs), which are equipment to create a vacuum in a closed space, have active magnetic bearings (AMBs). To reduce the size and cost of the TMP, this paper proposes the one-axis AMBs with single side electromagnetic drives. In conventional one-axis AMBs, the electromagnets (EMs) are set over and under the armature disc, whereas the proposed ones utilize the only upper EM. Moreover, permanent magnets (PMs) are attached at the top and bottom side of the rotor to generate magnetic attraction. In this paper, the proposed AMB using single side electromagnetic drive is analyzed and evaluated by simulation and experiments. Furthermore, characteristic variation due to TMP´s attitude is considered.