i build electro-mechanical system and i used stepper motor to move this system so i need to get transfer function for stepper motor to control the position of the shaft motor.
Following possibilities
1. You can try using simplified transfer function of synchronous motor widely available in literature.(or switched reluctance motors
2. Use fundamental of input waveform and D-Q transform
3. Use fundamental equations of force = -dWstored/ dtheta
Cheers
Narasim Ramesh can you mention any link of reference where i can find simplified transfer function of stepper motor ?
I am not aware of any ref. However please see if following could be of some help.It is highly simplified though.
1. Let us say we have supply voltage Vd (dc
2. This produces through switching , a balanced 2phase system of magn Eac ,
So Eac = kVd at some frequency w
3. Model the stepper motor as a voltage source Eb = K2* wr ( wr = rotor speed
4. Power input = Eac*Eb sin(delta) /Zseries ...say delta = torque angle Pinut
5. J dwr/dt +Tload = Pinput/wr
6. wr = d(delta)/dt wr = mech
You cans see this ia nonlinear eqn. For tranfser function using laplace viz s
linearize around steady operating point
Good Luck
Cheers.
here is a simpler basic approach for one coil with magnet at angle theta.
1. let flux of magnet = phim
2.max flux of coil = lm*i (assume or simplicity independent of theta)
3.then torqu =d(wstr/dtheta) = phim*lm*i*sin(theta)
4.toru= Jdwr/dt +Tload
5.wr= dtheta/dt
6. It is now possible to derive a linearized trf function with init input conditions
theta0 , i phim
7 you can use 6 as differnt coils are switched
Cheers
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