DYNAMICMODEL-ENCON动态模型的填充

《DYNAMICMODEL-ENCON动态模型的填充》由会员分享，可在线阅读，更多相关《DYNAMICMODEL-ENCON动态模型的填充（41页珍藏版）》请在装配图网上搜索。

1、Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,Dynamic Model of Induction Machine,MEP 1522,ELECTRIC DRIVES,WHY NEED DYNAMIC MODEL?,In an electric drive system,the machine is part of the control system elements,To be able to contr

2、ol the dynamics of the drive system,dynamic behavior of the machine need to be considered,Dynamic behavior of of IM can be described using dynamic model of IM,WHY NEED DYNAMIC MODEL?,Dynamic model complex due to magnetic coupling between stator phases and rotor phases,Coupling coefficients vary with

3、 rotor position rotor position vary with time,Dynamic behavior of IM can be described by differential equations with time varying coefficients,a,b,b,c,c,a,Simplified equivalent stator winding,i,as,Magnetic axis of phase A,Magnetic axis of phase B,Magnetic axis of phase C,i,cs,i,bs,DYNAMIC MODEL,3-PH

4、ASE MODEL,stator,b,stator,c,stator,a,rotor,b,rotor,a,rotor,c,r,DYNAMIC MODEL 3-phase model,Lets look at phase,a,Flux that links phase,a,is caused by:,Flux produced by winding,a,Flux produced by winding,b,Flux produced by winding,c,DYNAMIC MODEL 3-phase model,Flux produced by winding,b,Flux produced

5、by winding,c,Lets look at phase,a,The relation between,the currents in other phases,and,the flux produced by these currents,that,linked phase a,are related by mutual inductances,DYNAMIC MODEL 3-phase model,Lets look at phase,a,Mutual inductance between phase a and phase b of stator,Mutual inductance

6、 between phase a and phase c of stator,Mutual inductance between phase a of stator and phase a of rotor,Mutual inductance between phase a of stator and phase b of rotor,Mutual inductance between phase a of stator and phase c of rotor,DYNAMIC MODEL 3-phase model,v,abcs,=R,s,i,abcs,+d(,abcs,)/dt -,sta

7、tor voltage equation,v,abcr,=R,rr,i,abcr,+d(,abcr,)/dt -,rotor voltage equation,abcs,flux(caused by stator and rotor currents)that links,stator windings,abcr,flux(caused by stator and rotor currents)that links,rotor windings,DYNAMIC MODEL 3-phase model,Flux linking stator winding due to stator curre

8、nt,Flux linking stator winding due to rotor current,DYNAMIC MODEL 3-phase model,DYNAMIC MODEL 3-phase model,Flux linking rotor winding due to rotor current,Flux linking rotor winding due to stator current,Similarly we can write flux linking rotor windings caused by rotor and stator currents:,DYNAMIC

9、 MODEL 3-phase model,The self inductances consist of magnetising and leakage inductances,L,as,=L,ms,+L,ls,L,bs,=L,ms,+L,ls,L,cs,=L,ms,+L,ls,The magnetizing inductance L,ms,accounts for the flux produce by the respective phases,crosses the airgap and links other windings,The leakage inductance L,ls,a

10、ccounts for the flux produce by the respective phases,but does not cross the airgap and links only itself,DYNAMIC MODEL 3-phase model,It can be shown that the magnetizing inductance is given by,It can be shown that the mutual inductance between stator phases is given by:,DYNAMIC MODEL 3-phase model,

11、The mutual inductances between stator phases(and rotor phases)can be written in terms of magnetising inductances,DYNAMIC MODEL 3-phase model,The mutual inductances between the stator and rotor windings depends on,rotor position,DYNAMIC MODEL 3-phase model,stator,b,stator,c,stator,a,rotor,b,rotor,a,r

12、otor,c,r,DYNAMIC MODEL 3-phase model,DYNAMIC MODEL,2-PHASE MODEL,It is,easier,to look on dynamic of IM using,two-phase,model.This can be constructed from the 3-phase model using Parks transformation,Three-phase,Two-phase equivalent,There is magnetic coupling between phases,There is NO magnetic coupl

13、ing between phases,It is,easier,to look on dynamic of IM using,two-phase,model.This can be constructed from the 3-phase model using Parks transformation,stator,b,rotor,b,rotor,a,rotor,c,stator,c,stator,a,r,r,rotating,Three-phase,r,stator,q,rotor,rotor,stator,d,rotating,r,Two-phase equivalent,DYNAMIC

14、 MODEL 2-phase model,It is,easier,to look on dynamic of IM using,two-phase,model.This can be constructed from the 3-phase model using Parks transformation,r,stator,q,rotor,rotor,stator,d,rotating,r,Two-phase equivalent,However coupling still exists between stator and rotor windings,DYNAMIC MODEL 2-p

15、hase model,All the 3-phase quantities have to be transformed to 2-phase quantities,In general if,x,a,x,b,and,x,c,are the three phase quantities,the,space phasor,of the 3 phase systems is defined as:,where,a=e,j2,/3,DYNAMIC MODEL 2-phase model,All the 3-phase quantities have to be transformed into 2-

16、phase quantities,d,q,DYNAMIC MODEL 2-phase model,The transformation is given by:,For isolated neutral,i,a,+i,b,+i,c,=0,i.e.i,o,=0,i,dqo,=,T,abc,i,abc,The inverse transform is given by:,i,abc,=,T,abc,-1,i,dqo,DYNAMIC MODEL 2-phase model,DYNAMIC MODEL 2-phase model,v,abcs,=R,s,i,abcs,+d(,abcs,)/dt,v,abcr,=R,rr,i,abcr,+d(,abr,)/dt,IM equations,:,r,stator,q,rotor,rotor,stator,d,rotating,r,3-phase,v,dq,=R,s,i,dq,+d(,dq,)/dt,v,=R,rr,i,+d(,)/dt,2-phase,dq,where,Express in stationary frame,Express in ro