TIDUF67 April 2024 – December 2024
This is the most important transformation in the FOC. In fact, this projection modifies a 2-phase orthogonal system (α, β) in the (d, q) rotating reference frame. If we consider the d axis aligned with the rotor flux, Figure 3-5 shows the relationship for the current vector from the two reference frame.
The flux and torque components of the current vector are determined by Equation 12.
where θ is the rotor flux position.
These components depend on the current vector (α, β) components and on the rotor flux position; if we know the right rotor flux position then, by this projection, the d,q component becomes a constant. Two phase currents now turn into dc quantity (time-invariant). At this point the torque control becomes easier where constant isd (flux component) and isq (torque component) current components controlled independently.