Power operating domain of a cascaded doubly fed induction machine

The paper deals with the steady state operating limits of a cascaded doubly fed induction machine (CDFIM) in terms of active and reactive powers. An analytic method is suggested to derive the power region, in which the machine can operate safely without exceeding its rated parameters. The proposed steady-state analytical study has been thoroughly validated by simulations using an elaborated model of the CDFIM implemented on Matlab-Simulink. It is shown that the power capability is subject to several limitations. For a limited speed range the reactive power consumption and generation are determined by the stators current maximum values. The study is further extended to illustrate the effect of the slip range and the terminal voltage on the power limit curves.