| Abstract |
This paper deals with an improved method enabling the simulation of inter-turn short circuits in the stator windings of induction machines. This method is based on the coupled magnetic circuit theory. The system of differential equations describing the induction machine in presence of inter turn short circuits in the stator windings is given. The calculation of the machine inductances is based on the integration of the magnetic energy density stored in the airgap. The airgap magnetic energy is determined by means of the winding functions method. The theoretical foundations of this airgap magnetic energy based calculation of the machine inductances are presented. In addition, the doubly slotted air-gap is taken into account by the use of a sophisticated airgap permeance analytical model derived from several finite elements simulations. Because of the inductances calculation is highly time consuming, a numerical representation method of the inductances is also proposed in order to avoid calculating inductances during the differential equations system integration. The proposed model allow the authors to study precisely the inter-turn short circuits signature in various machine quantities such as stator currents, torque, speed, etc. Finally, the simulation results of the proposed model are validated by means of a 4 kw specially rewound induction motor which is loaded by a DC generator. |
