Research On Fault-tolerant Control Of Single Winding Bearingless Slice Motor At Phase-lack

By using bearingless technology, bearingless slice motor achieves the rotation and suspension of rotor. Meanwhile, it has characters like high integration, high axial-utilization, complete separation between stator and rotor and other advantages. As a high sealed, ultra-clean, no cross-contamination green drive technology, bearingless slice motor has extensive application prospects in aerospace, defense, industrial, agricultural production and daily life fields.Abandoning double-winding structure in traditional bearingless slice motor, single-winding bearingless slice motor achieves the motor suspension and rotation control simultaneously by using a set of stator windings. This increases the reliability and fault-tolerance performances of bearingless slice motor with the advantage of simple structure.This paper deals with six-phase single-winding bearingless slice motor as the research object, with phase-lack fault-tolerant operation as the research content. And it mainly has completed the following research work:Firstly, this paper deeply studies the suspension force and torque mathematical models of single-winding bearingless slice motor and analyzes the causes of levitation pulse theoretically. On this basis, it analyses the stator current constraint conditions to meet the motor's stable suspending operation, which lays the foundation for realization of phase-lack fault-tolerant control.Secondly, aiming at single-winding bearingless slice motor's characters of stator current independent control in each phase and the reconstruction of remainder stator phase currents to achieve fault-tolerant operation while phases lacking, this paper researches phase-lack fault-tolerant control strategies based on rotating coordinates and based on stator current decoupling model respectively. The former makes use of motor's structure symmetry and cites the rotating-coordinate method to solve the issues including excessive mathematical model of phase-lack fault-tolerant control, system complex, which are all due to phase-windings'different positions. The latter takes advantage of existing controller's high-speed computing capability and proposes phase-lack fault stator current decoupling control model. It achieves the reunification of stator current fault-tolerant control models under phase-lack conditions among different phase windings. Ansys simulation analysis and experimental validations have been done respectively about these two control strategies in this paper. And results show that the two control strategies can both realize the fault-tolerant control for motor's phase-lack fault. Finally, phase-lack fault diagnostic program, rotating-coordinate method phase-lack fault-tolerant control program, stator current decoupling model phase-lack fault-tolerant control program are written for the digital control system based on TMS320F2812 as the core.