Magnetically levitated rotor spinning drive system with high system stability

This paper describes a high speed drive system for textile rotor spinning applications with individually driven spinning units. High energy efficiency and lifetime is obtained by utilization of a slotless electronically commutated PM motor and active magnetic bearings for rotor suspension. Compared to traditional, centralized driven machines the proposed configuration allows a rotor design open at both sides. The result is an advanced arrangement of the spinning components and an improvement in the spinning process. Each unit includes its own power and signal electronics. The PM motor, with rotational speeds of up to 150 000 rpm, is supplied by a quasi current source inverter (QCSI) and controlled by means of back EMF based, position sensor — less control. An uninterruptable power supply (UPS) is inevitable for the magnetic bearing section to avoid a fatal rotor crash in case of a power supply interruption. A QCSI in a bidirectional configuration is used to supply the bearing section in this condition by utilizing the stored kinetic energy of the PM motor. An additional external UPS is not necessary for reliable system operation.