Multislice Inter-Bar Model for Large Synchronous Machines With Skewed Stator Slots

This paper describes an implementation of the time-stepped multislice finite-element method including a rotor inter-bar model in simulations of large skewed synchronous machines. The general form of the system equations is developed with an improved definition of inter-bar loop currents in order to enhance the numerical stability at large inter-bar resistances. In order to reduce simulation time, finite-element analysis (FEA) algorithms are implemented to exploit multiple processing cores. The simulations predict the flux density distributions and induced voltage harmonics at various inter-bar resistances for a synchronous generator under open-circuit operation. The simulated voltage harmonics are compared to test results and results obtained using conventional two-dimensional FEA and traditional skew factors.