Airgap induction of five-phase induction machines operating with one opened phase
The distribution of the induction in the airgap of five-phase induction machines operating with an open phase is investigated. Analytical expressions are given in terms of steady-state symmetrical components which are related directly to the airgap induction. It is shown that under fault, third harmonic induction components arise which can potentially produce extra magnetic losses in the stator and rotor. Three operation modes are assessed: uncontrolled, current control with joule losses minimization, and current control with equal stator currents. The results for a prototype machine are discussed considering winding losses, torque pulsations, and the distortion of the airgap induction compared with the normal operation.