Ultrafast steady-state multi-physics model for PM and synchronous reluctance machines

A new technique for coupling the electromagnetic, thermal, and air-flow analysis is proposed especially for electric machines that exhibit a reduced dependency of core losses with temperature and load, and have low rotor losses. Within the overall iterative loop, another inner loop that cycles only the thermal calculations and employs a simplified model for estimating losses is introduced. The thermal and air-flow analysis models the conduction, radiation, and convection heat transfer and is based on equivalent circuit networks. A computationally efficient FE technique is employed for the electromagnetic field analysis. The combination of algorithms results in ultra-fast processing as the number of outer loop iterations, which include electromagnetic FEA, is minimized. The overall computational time is significantly reduced in comparison with the conventional method, such that the new technique is highly suitable for large scale optimization studies. Example simulation studies and measurements from an integral hp IPM motor are included to support validation.