Field-oriented control of saturated AC machines

A nonlinear field-oriented model is derived for saturated AC machines. The theory is applied to a field-oriented controlled induction machine operating in the field-weakening region where the change of saturation of the main flux paths plays an important role. It is shown that with the implemented current control, the control response is seriously distorted by the effects of variable saturation during field-weakening. When the linear model is used it is not possible to show these distortions