- #1
Ziya
- 2
- 0
I know that decoupling the 3 phase currents we get the id and iq (in rotor frame) currents which control the flux and torque respectively. But where does the relation come from?
Thank you. I got it now.Hesch said:I think ( don't know for sure ) that if we have an instant stator current, Istat, that induces a B-field ( Bstat ) which has an angle α to Brotor,
then the Istat is decomposed into Id = Istat * cos α , Iq = Istat * sin α.
In this way Id will not yield any torque, because BId has an angle to Brotor = 0.
BIq has angle to Brotor = 90°, so Iq will yield a torque.
That's why a vector-controlled system tries to control Id to be zero, thus increasing the efficiency of the motor.
Controlling a synchronous motor, you don't need these Id's and Iq's: You just measure the angular position of the rotor by means of an encoder, then induce a current in the stator that will create a Bstat, that is perpendicular to the Brotor.
The q-axis stator current is a crucial component in controlling the torque output of a 3-phase induction motor. This is because it is responsible for creating the rotating magnetic field that interacts with the rotor to produce torque. By controlling the magnitude and phase angle of the q-axis stator current, the torque output of the motor can be effectively regulated.
The q-axis stator current controls the torque in a 3-phase induction motor through the principle of electromagnetic induction. When an alternating current flows through the stator windings, it creates a rotating magnetic field. This field interacts with the conductors on the rotor, inducing a current and producing a torque that drives the motor.
Yes, the q-axis stator current can also indirectly control the speed of a 3-phase induction motor. By adjusting the magnitude and phase angle of the current, the strength and direction of the magnetic field can be changed, thereby influencing the speed at which the rotor rotates and the resulting torque output.
No, the q-axis stator current is not the only factor that affects torque in a 3-phase induction motor. Other factors such as the number of stator and rotor poles, the type of rotor construction, and the load on the motor can also impact the torque output. However, the q-axis stator current is a critical factor in controlling and regulating the torque output of the motor.
The q-axis stator current can be controlled in a 3-phase induction motor through various methods such as scalar control, vector control, and field-oriented control. These methods use different control algorithms and techniques to regulate the magnitude and phase angle of the current, thereby controlling the torque output of the motor.