Efficient dynamic models for induction machines

A computationally efficient reluctance mesh model suitable for simulating the dynamic performance of practical induction motors is presented. The calculation time is minimized by direct computation of rate of change of flux, avoiding unnecessary evaluation of time and rotor position dependent inductances. The magnetic, electrical and dynamic models of the machine are coupled so that the simulation determines both steady state and transient behaviour including the effects of saturation and high order torque harmonics due to the rotor and stator teeth. The algorithm is developed from rigorous field theory. This is combined with and simplified by, practical experience, resulting in a procedure that can efficiently simulate 3D machines within an iterative design environment without requiring extensive computational resources. Full details of the implementation are presented along with simulations and experimental characterization of a practical induction motor which are found to be in ‘excellent’ agreement.