ABSTRACT
In earlier chapters we have indicated that vector control implies independent (decoupled) control of flux and torque in an induction motor. In this chapter, we will present the fundamentals of vector control of synchronous machines. As we know, except for reluctance machines, most synchronous machines have either electromagnetic excitations or permanent magnets (PMs) on their rotors. For analysis, a high-energy PM may be replaced by a fictitious winding carrying a constant field_ current. So, the input to a synchronous machine consists of the stator (or airgap) flux, X], the field current, ip, and the torque, 7^ . However, because the field current is adjusted to a predetermined value according to a power factor criterion, the synchronous machine reduces to a two input device just like an induction machine. In the following, we treat only the sinusoidal current control, but not the rectangular current control [1], [2].
