Study On Flux Density And Iron Loss Of Three Phase 6/4 Structure Switched Reluctance Motors

Firstly,the research background of flux density and iron loss of switched reluctance motor and the present research status at home and abroad are introduced in this thesis.The advantages and disadvantages of the equivalent circuit method and the finite element method for calculating the flux density and iron loss of the motor are analyzed.The problems that need to be solved in the calculation of flux density waveforms and iron loss of switched reluctance motor are presented.Secondly,the finite element model of the static flux field of a three-phase 6/4 structure switched reluctance motor is established in the finite element software FLUX.Then the distribution of the flux field in different positions of the motor is analyzed.Based on the distribution of the flux field,the core of the motor divided into several regions.Based on the finite element model of transient flux field,the characteristic of flux density waveform in different parts of the stator and rotor is analyzed.According to the comparative analysis of static flux field and transient flux field,a new fast calculation model for calculating flux density of switched reluctance motor is proposed based on the analytical model of flux density waveforms of motor.Thirdly,the mechanism and traditional calculation model of the iron loss of switched reluctance motor are summarized and analyzed,and an improved calculation model of iron loss is proposed.The model uses the method of data fitting to obtain the loss coefficients with the change of flux density and frequency.In order to improve the accuracy of the iron loss,the effects of rotating magnetization and hysteresis minor loops on the iron loss are considered.Fourthly,by using the coordinate conversion formula,the X and Y axis components of static flux density are converted into radial components and tangential components.Based on the proposed fast calculation model of the flux density waveform,a module for calculating the flux density of the switched reluctance motor is built in MATLAB/Simulink by using look-up tables.The simulation results of flux density are compared with the finite element results,and the accuracy of the flux density calculation model is verified.At the same time,the simulation module of iron loss is established according to the proposed improved iron loss calculation model,and the simulation results of iron losses under different turn-on angles and turn-off angles are analyzed.Then the distribution of the switched reluctance motor iron loss are obtained,and the influence of the load condition,turn-on angle and turn-off angle on the iron loss of the motor is analyzed.Finally,the experimental platform is built,and the iron loss model of the motor is verified experimentally.The direct measurement method is adopted to measure the mechanical loss of the motor.The measured iron loss is indirectly calculated by the total loss minus the mechanical loss,the copper loss and the stray loss of the motor.The iron loss simulation results and experimental results are compared.The comparison shows that the simulation results of iron loss are in good agreement with the experimental results,which verifies the accuracy of the iron loss model and indirectly verifies the accuracy of the flux density calculation model.