Steady‐state operation of the brushless cascaded doubly fed machine: a survey

Purpose – The purpose of this paper is to investigate the steady‐state stability and features of the brushless cascaded doubly fed machine (BCDFM), which is made up of two wound‐rotor induction machines: the power machine (PM) and the control one, with their rotors mechanically and electrically coupled.Design/methodology/approach – The machine modelling is first treated considering a Park reference frame linked to the rotating field of the PM. Then, a state representation related to small perturbations is established following the linearisation of the BCDFM model around a steady‐state operating point. This allows the investigation of BCDFM steady‐state stability, power flow and the torque‐speed characteristics.Findings – It has been found that the electrical variables of the control machine greatly affect the BCDFM steady‐state stability and characteristics.Research limitations/implications – The work should be extended considering a validation of the established results through experimental tests.Origina...