Research On The Torque Characteristics Of Doubly Salient Electro-magnetic Motor And Torque Ripple Reduction Technology

Doubly salient electro-magnetic machine is one kind of the reluctance machines with doubly salient structure.DC field winding and armature winding are placed in the stator slot and there is no permanent magnet and winding on the rotor.Consequently,this kind of machine has the advantages of low cost,high temperature resistance and no demagnetization risk,which can use the field winding to change magnetic flux and is suitable for the working conditions of high speed and harsh environments.This paper considers design parameters and control strategies of the DSEM synthetically and analyses the torque characteristics mainly by the aspects of static torque and dynamic torque.At first,this paper introduces the structure and mathematical model of DSEM.The similarities and differences about the mechanism that the torque is produced are compared between DSEM and SRM.Based on the research of DSEM with the conventional rotor pole arc and the 12/8 structure,this paper compares the standard angle control,the advance angle control and the asymmetrical current control method and it expounds the necessity of considering the rules of back EMF and inductance variation in the process of electric machine control.Subsequently,the static torque characteristics of DSEM models with different rotor pole arc are researched,including cogging torque,optimal magnetomotive force Ratio and the maximum static torque curve.This paper comparatively analyzes the influence of different rotor pole arcs on the static torque characteristics of DSEM,which lays the foundation for the study of DSEM electric control.The prototype is used to make the locked-rotor test,which verifies the correctness of the simulation results.In the end,the dynamic torque characteristics on DSEM models with different rotor pole arc are researched.Firstly,this paper studies their no-load characteristics and inductance characteristics,which lays the foundation for the analysis of electric characteristics.It researches the electric characteristics with the methods of the standard angle control and the symmetric current control.It is analyzed that the proper widened rotor pole increases the torque density of DSEM,and further widened rotor pole restrains the torque ripple of DSEM at the cost of the reduction of output torque.Experiments are conducted on the experimental platform of DSEM drive system,the mechanical characteristic curve under different load of the widened rotor pole DSEM are obtained,and comparison between DSEMs with widened rotor pole arc and conventional rotor pole arc are conducted.