Analysis and control of six-phase induction machines in unbalanced operating situation due to phase opening

Abstract

This paper deals with speed control of a squirrel cage six-phase induction machine (SC6PIM) in phase opening occurrences. A decoupled model of induction machine with unbalanced structure is given to analyze the phase opening operation of the SC6PIM. In order to reduce torque oscillations created in phase opening events, a fault-tolerant operation method by using indirect rotor field oriented control (IRFOC) technique is proposed and used to control the speed of the SC6PEVI in each faulty operation. The proposed controller will be renewed in each fault situation of machine regarding the number and type of missed phases. Furthermore, in this paper, switching between controllers in some different cases is investigated and real time initial conditions setting for controllers is proposed to minimize the transient problems in switching instant. To evaluate the performance of proposed method, the experimental results are obtained on a small SC6PIM rated at 90 W.