Vector Control With Optimal Torque Per Ampere And Investigtion Of Processing Influence For Synchronous Reluctance Motors

Firstly,the working principle of synchronous reluctance motor(SynRM)is described.Then,relationship between the flux linkage,voltage,inductance and current is established at the three-phase stationary reference frame,and is then transformed to the two-phase rotating frame with the constant phase and amplitude transformation.The machine model at the rotating frame is much simpler,whilst the relationship between various vectors is clearer.Due to the saturation effect of the magnetic material,in practical operation,the d-and q-axis inductances of the SynRM vary with the d-and q-axis currents.Therefore,it is necessary to investigate the variation relationship between the inductances and the currents.According to the relationship,the SynRM simulation model is thus built,based on which the ratio of the d-and q-axis currents can be determined in such a way that the torque per ampere can be optimized with the vector control.Three kinds of vector control methods are analyzed in this thesis,viz.(1)id=iq control under the ideal motor model,(2)using a function to fit the d-axis inductance variation with the d-axis current while assuming the q-axis inductance being constant,and deducing the d-and q-axis currents relations,and(3)using finite element method(FEM)to find the minimum value of the current to achieve any given torque,then obtaining the relationship between the d-and q-axis currents relations for the demanded torque.And then,for the given torque,the current amplitudes obtained with these three control methods are compared,so that the optimal vector control method of the SynRM is realized.In order to impelement the drive and control of the SynRM,an experimental platform with both hardware and software is presented.The hardware includes a control board,a PWM signal adapting board,power converter modules,an encoder board,and a current sensing board.On the hand,the current measurement,the initial rotor position detection and the speed measurement of the SynRM are implemented with the software,which also realizes all the control functions according to the system block diagram.On the other hand,the manufacturing and assembling imperfectness usually has a negative effect on the SynRM performance.With an optimized SynRM,the influence of the punching burrs,material local degrading caused by punching,interlocking dowels,riveting errors and the eccentricity between the stator and rotor on the average torque,torque ripple,efficiency and radio force is studied in detail.Through the analysis of these influence,the critical processing techniques can be concluded,which should be controlled strictly during the manufacturing and assembling of the SynRM.