Research On Fault-tolerant Control Of Bearingless Permanent Magnetic Slice Motor With Winding Or Power Inverter Fault

Single winding bearingless permanent magnetic slice motor (SWBPMSM) can achieve therotation and suspension because of its unique structure. The single winding structure also make themotor has some fault-tolerant possibility. So this kind of motor has some advantages like highintegration, no friction, super clean and fault-tolerant. Therefore, it has a broad application prospect inthe fields of aerospace, semiconductor manufacture, medical industry and chemical industry.This thesis takes the multi-phase SWBPMSM as the research object, researching thefault-tolerant control of the motor with faulty phases or faulty power switches in its inverter system.The main content can be concluded as follow:Firstly, according to the structure of motor and the distribution of air-gap flux, the mathematicalmodel of short-circuit current was derived. By analyzing and comparing the impacts from windingsmutual inductance, winding self-inductance and permanent magnet on the short-circuit current, thecurrent model was simplified. On this basis, the transient analysis of short-circuit current has beencarried out, which pointed out that transient component of short-circuit current cannot be ignored.Secondly, a criteria which can determine the feasibility of fault-tolerant control has beenproposed to avoid the blindness of simulation and experiment. As a result, the problem that whetherthe system can achieve fault-tolerant control when open or short-circuit fault happened in multiplephases simultaneously has been answered. Aiming at the problem that fault-tolerant control strategiesare different for different types of motor failures, a matrix-based fault-tolerant control strategysuitable for ordinary fault modes were presented. The strategy can achieve fault-tolerant control whensingle phase or two phases of motor break down. The fault-tolerant control strategy was verified byfinite element simulation and prototype experiment.Thirdly, the problem that motor driven by H-bridge cannot run normally due to fault of powerswitches in power inverter system was analyzed. Work modes of H-bridge were summarized when thepower switches get open or short circuit and the impact on the system was also analyzed. Methods ofprotection after fault diagnosis were proposed so that the failure of power switches can equal towinding faults and the fault-tolerant control can be achieved. Taking the experiments of the first andsecond phases’ power switches working at open-circuit and short-circuit fault state for example, thevalidity of the theoretical analysis referred were fully proved.Finally, software of prototype control system, fault-tolerant control program and procedures related to fault diagnosis were designed for the digital control system based on TMS320F2812as thecore.