Field oriented and field acceleration control for induction motors: Is there a difference?

The field acceleration method (FAM) and the indirect field-oriented control (FOC) for current-fed induction machines are theoretically compared, and their block diagrams are analyzed. It is shown that the indirect FOC and the T-1 type FAM are exactly the same. Moreover, the equivalence between the spiral vector used in FAM and the space vector used in FOC is demonstrated. The FOC theory explains the direct FOC, where an estimation of a direct measurement of the rotor flux is done. This direct scheme allows independent control loops for flux and torque, and thus can be considered more general than the FAM or the indirect FOC.<>