A new circuit-oriented model for the analysis of six-phase induction machine performances

This paper deals with a six-phase induction machine design for 42 V embedded applications such as electrical power steering. This machine has symmetrical 60° displacement windings which allow fault-tolerant modes. In fact, when one or more phases are opened, the machine is able to rotate with a torque reduction. A simple circuit-oriented model has been proposed in order to simulate the six-phase squirrel-cage induction machine and to predict its performances. The proposed method consists in the elaboration of an electric equivalent circuit obtained from minimal dimensional knowledge of stator and rotor parts. It takes into account only the magnetic circuit dimensions and the airgap length. A six-phase squirrel-cage induction machine of 0.09 kW, 17 V, 50 Hz, two poles has been used for the experimental set-up. A design program including the non-linear electromagnetic model has been also used with a complete description of stator and rotor cores using the iron non-linear characteristic for the final verification. The simulation results given by the two models are compared with the experimental tests in order to verify their accuracy. The harmonic analyses of stator currents are also compared to go further in the model validations.