9.5. Control Design
9.5.1. Proportional–Integral Control Design
In the case of the stator flux orientation in the d–q reference frame, the d-axis component of the stator current isd is directly proportional to the magnitude of the stator flux φs. The d-axis component of the stator current isd is then directly proportional to the magnitude stator flux. By regulating and keeping constant isd, the decoupling of the torque control and the flux of the induction machine is achieved. Hence, if the stator flux is oriented along the d-axis, then φs = φsd and φsq = 0.
The transfer functions obtained from this calculation of the flux and torque are then used to design the corresponding PI controllers as depicted in the generic bloc diagram of Fig. 9.59. All ...