I am new guy using Sicenter Amesim and working with EMD library for electric machine control. In the linear submodel EMDPMSM01 for permanent magnet synchronous machine (3Phase), there is a parameter "electrical angle". I cannot find the explanation about this parameter. Is it rotor inital position or reference frame position or something else?
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This is how the electrical angle is defined:
p is the number of pole pairs.
See with the demo named PMSM_ModelComparison, below the "electrical angle" is compared with the integral of "pole pairs * rotor relative speed"
Maybe just a small precision compared to the previous answer.
For synchronous machine, the stator phase A is the reference of the stator. The rotor field is the reference of the rotor. The electric angle is the angle between the stator and the rotor reference frame:
This is why this electric angle “thetae” is linked to electric machine mechanical angle “thetam” with the relation:
thetae = p*thetam
“p” being the machine pole pair numbers.
Hi Emmanuel_D and fpasteur,
Thanks for the explanation.
If i understand correctly, the parameter "electric angle" is the angle between rotor field and the stator reference. As fpasteur mentioned, for syncrhonous machine, the stator reference is in general the magnetic field center of phase A. So if the stator is stationary (in most modeling case), i can call this parameter as initial position of the rotor (assume the position of rotor is defined by the angle between them).
Basically this electric angle will vary as the motor is rotating. For synchronous machine, we use this angle to evaluate the stationary quantities of the machine in the rotating Park frame. So you cannot call it the initial rotor position. Nevertheless you are right, since this angle is a state variable you can set to it a non-zero initial value. And indeed it is like if the motor field is starting at this initial electric angle position. If you use this field like that, don't forget to report this initial angle to your motor controler.