Ultrafast Steady-State Multiphysics Model for PM and Synchronous Reluctance Machines

A new technique for coupling the electromagnetic, thermal, and airflow analysis is proposed particularly for electric machines that exhibit reduced dependence 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 to estimate losses is introduced. The thermal and airflow analysis models the conduction, radiation, and convection heat transfer and is based on equivalent circuit networks. A computationally efficient finite-element (FE) technique is employed for the electromagnetic field analysis. The combination of algorithms results in ultrafast processing as the number of outer loop iterations, which include electromagnetic FE analysis, 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 horsepower interior permanent-magnet motor are included to support validation.