High-Accuracy Lumped-Parameter Thermal Modeling for Fractional-Slot Concentrated-Winding PMSMs Under Short-Circuit Fault Conditions

This article proposes a high-accuracy lumped-parameter (LP) thermal modeling method to predict maximum winding temperatures and the asymmetric winding temperature distributions under short-circuit (SC) fault conditions for fractional-slot concentrate slot fraction-slot concentrated-winding (FSCW) permanent magnet synchronous machines (PMSMs). It is the first time to consider the nonuniform loss distribution in the analytical LP thermal modeling by introducing a compensation thermal resistance. It is derived from the multidimensional conduction heat transfer theorem into the conduction thermal network to represent the uniform and nonuniform copper loss distributions under SC conditions for PMSMs with either single- or double-layer windings. Compared to the traditional LP thermal modeling method that significantly misestimates the winding temperature under SC conditions and provides inaccurate fault features, the proposed method can achieve excellent estimation accuracy as the numerical method with high computational efficiency. The proposed method is validated by both the numerical method and experiments based on a prototype FSCW PMSM.