Research On Steady-State Performance Of Multiphase Induction Motor With Non-sinusoidal Power Supply And Sleeve Cuttin

The new type of ship induction propulsion motor generally adopts multi-set multi-phase concentrated integral pitch winding structure,and the material utilization rate and torque density of the motor are improved with non-sinusoidal power supply.Meanwhile,multi-set multi-phase winding structure can be flexibly put into or cut out according to the actual working condition of the motor,especially suitable for the occasions with strict reliability requirements.When one phase of the motor is open-circuited,the whole set of windings where the fault phase is located can be cut out from the system to ensure the normal operation of other phase windings and ensure the symmetrical operation of the motor to the maximum extent.Therefore,it is necessary to study the operation of multi-phase induction propulsion motor with different sets of windings and non-sinusoidal power supply.In this paper,a fifteen-phase induction motor with three sets of five-phase windings is taken as an example.The variation of air gap magnetic potential during different operation of the motor under non-sinusoidal power supply is analyzed.The motor parameters under corresponding operating conditions are calculated and the variable parameter equivalent circuit of multi-phase induction motors with different sets of windings is established.And the optimal harmonic injection quantity of the fifteen-phase induction motor is studied.On this basis,the influence of non-sinusoidal power supply on the steady-state performance of the motor during different operation of the fifteen-phase induction motor is studied,and the results are verified by simulation and experiment.Firstly,based on the basic principles of electrical machinery,the fundamental and harmonic magnetic potentials generated by the fundamental currents in single-turn winding and single-phase winding are deduced,and then the fundamental and harmonic magnetic potentials generated by the non-sinusoidal currents in multi-phase winding are analyzed.The magnetic potential of the fifteen-phase induction motor composed of three sets of five-phase windings is obtained when it runs normally,when it cuts one set of windings,when it cuts two sets of windings,and the variation law of the magnetic potential of the multi-phase induction motor with non-sinusoidal power supply is summarized.Secondly,by introducing the correlation matrix to reflect the actual input and cutting operation of stator windings,the fundamental and third-order harmonic stator leakage reactance of the motor with different sets of windings is calculated.The corresponding relationship between the fundamental and third-order harmonic excitation currents and the excitation inductance is calculated by using the distributed magnetic circuit method,and the excitation inductance corresponding to any excitation current can be obtained by using the three-dimensional interpolation method,and the variable parameter equivalent circuit of multi-phase induction motors with different sets of windings is established.Then,the harmonic current injection mode and harmonic injection quantity constraint conditions are determined.Through the expression of fundamental and harmonic magnetic potential function,the optimal harmonic injection quantity is obtained theoretically when the motor is in normal operation and different cutting sets of windings operation by using derivation and mesh method,and the effect of harmonic current injection of different times is compared and analyzed.Finally,based on the variable parameter T-type equivalent circuit and the load characteristics of propeller,the influence of harmonic injection before and after the third-order harmonic injection on the steady-state performance indexes such as electromagnetic torque,efficiency and power factor in the operation of the motor is calculated.And the influence of different harmonic injection quantity on the steady state operation performance of the motor with differentsets of windings is calculated,which provides theoretical support for non-sinusoidal power supply multi-set multi-phase induction propulsion motor cutting different sets of windings steady operation.