Postfault Operation of an Asymmetrical Six-Phase Induction Machine With Single and Two Isolated Neutral Points

The paper presents a study of postfault control for an asymmetrical six-phase induction machine with single and two isolated neutral points, during single open-phase fault. Postfault control is based on the normal decoupling (Clarke) transformation, so that reconfiguration of the controller is minimized. Effect of the single open-phase fault on the machine equations under this control structure is discussed. Different modes of postfault operation are analyzed and are further compared in terms of the achievable torque and stator winding losses. Validity of the analysis is verified using experimental results obtained from a six-phase induction motor drive prototype.