Research On Hybrid-single/doublelayer-winding Five-phase Permanentmagnet Synchronous Machine And Its Fault-tolerant Control Strategies

The electric machine systems are gradually replacing the traditional internal combustion engine and hydraulic device,and becoming the mainstream schemes of power or actuator devices in the field of transportation such as vehicle,aerospace and ship.As important indexes of the power or actuator devices,reliability has always been the focus.As a fault-tolerant machine scheme with high power density,high reliability and high fault-tolerant capability,the multi-phase fault-tolerant permanent magnet synchronous machine is an ideal choice for the power or actuator devices in the field of transportation in the future.In order to improve the fault-tolerant capability of the multi-phase fault-tolerant permanent magnet synchronous machine,the hybrid-single/double-layer-winding five-phase permanent-magnet synchronous machine(HSDW-FPPMSM)scheme is proposed in this thesis.The HSDW-FPPMSM has excellent electrical,magnetic,thermal and physical isolation capabilities,which is helpful to further promote the application of multi-phase fault-tolerant permanent magnet synchronous machine in vehicle,aerospace,ship and other transportation fields.The main research work of this thesis is as follows:Firstly,electromagnetic scheme of the HSDW-FPPMSM is investigated.The influence factors of mutual inductance of the traditional fractional-slot concentrated winding fault-tolerant permanent magnet synchronous machine are analyzed,and the low mutual inductance design principle of this type of machine is given.The HSDW-FPPMSM scheme is proposed.The principle for slot/pole combination selection and armature magnetomotive force(MMF)harmonic distribution of the HSDW-FPPMSM are investigated.The variation law of armature MMF with slot opening span angle of the HSDW-FPPMSM is given.The analytical model of inductance of the HSDW-FPPMSM under normal operation is established,and the variation laws of inductance components with slot opening span angle and slot opening width are given.The influence laws of key dimensions such as fault-tolerant tooth size and air gap width between modules on MMF harmonic distribution,mutual inductance,etc.are investigated,and the design methods for improving power density and fault isolation capability of the HSDW-FPPMSM are given.Secondly,inter-turn short-circuit fault model and winding fault diagnosis method of the HSDW-FPPMSM are investigated.The flux distribution law of the HSDW-FPPMSM under inter-turn short-circuit fault is analyzed.The inductance model of the HSDW-FPPMSM under inter-turn short-circuit fault is established,and the relationship between inductances of the short-circuit phase and number and position of short-circuit winding is given.The analytical model of short-circuit current considering mutual inductance between remaining healthy winding and short-circuit winding is established,and the influence laws of turn number and position of the short-circuit winding and the remaining healthy winding current on the amplitude and phase of short-circuit current are investigated.The winding fault diagnosis method of the HSDW-FPPMSM based on double detection coils is proposed.The variation laws of induced electromotive force(EMF)amplitude and phase of the detection coils under different fault types and fault positions are investigated,and the diagnosis methods of fault types and fault positions are given.Thirdly,the open-circuit fault-tolerant control(FTC)strategy of the HSDWFPPMSM is investigated.The harmonic distribution law of the armature MMF of the HSDW-FPPMSM under open-circuit fault is analyzed,and the influence of stator and rotor magnetic field harmonics on torque of the HSDW-FPPMSM under open-circuit condition is revealed.Aiming at the problem of poor open-circuit fault-tolerant effect caused by high no-load back EMF harmonic content of the HSDW-FPPMSM,an open-circuit FTC strategy with positive utilization of back EMF harmonics is proposed.The relationship between torque ripple suppression degree and torque performances under fault-tolerant operation is investigated.Comparitive investigations are made between the proposed FTC strategy and the traditional MT strategy.The effects of back EMF harmonic distribution and zero-sequence current constraints on torque performance under fault-tolerant operation are investigated.The selection principles of FTC strategies under different situations are given.Then,the short-circuit FTC strategy of the HSDW-FPPMSM is investigated.The armature MMF harmonic distribution law and torque components generated by short-circuit current under short-circuit fault condition are analyzed.Aiming at the problem of torque output reduction caused by constraining d-axis armature MMF under the short-circuit fault-tolerant condition,a short-circuit FTC strategy without constraint on d-axis MMF is proposed.The effects of releasing the d-axis MMF constraint on torque performance,phase voltage,flux density distribution,losses and efficiency of the machine are analyzed.Aiming at the problem of increasing torque ripple caused by ignoring the short-circuit phase resistance under low-speed operation,a short-circuit FTC strategy with consideration of resistance of the short-circuit phase is proposed.The influence of rotor magnetic field harmonics on the effect of short-circuit FTC is investigated.Aiming at the increase of torque ripple caused by rotor magnetic field harmonics,a short-circuit FTC strategy based on torque ripple component offset is proposed.Finally,a 15-slot/12-pole HSDW-FPPMSM prototype and a five-phase fullbridge driver are developed and manufactured,and an experimental test bench is built to verify the theoretical analysis of this thesis.The performance under normal operation,parameters and fault diagnosis methods under fault condition of the HSDW-FPPMSM prototype are tested,and the open-circuit and short-circuit FTC strategies are verified.The parameters and operation performances of the HSDWFPPMSM prototype under normal and fault conditions are in good agreement with the theoretical analysis results,and the fault diagnosis method is effective.In addition,the open-circuit and short-circuit FTC strategies proposed in this thesis are effective in improving the operation performances of the HSDW-FPPMSM under fault condition.