PM Synchronous Machine Drive Response to Asymmetrical Short-Circuit Faults

This paper investigates the impact of machine topology and parameters on the fault-mode characteristics of permanent-magnet synchronous machines (PMSMs) exposed to asymmetrical short-circuit (ASC) faults, one of the most dangerous faults in terms of peak current amplitudes and demagnetization risks. Simulations using an equivalent circuit model combined with finite-element (FE) analysis are used to explore the differences between the ASC fault-mode responses of three major types of PM machines. The effects of several different rotor and winding configurations have been studied to identify the key machine parameters that have a major influence on the fault current amplitudes. Results indicate that fractional-slot concentrated winding (FSCW) PM machines tend to exhibit lower peak currents compared to distributed winding (DW) machines during ASC fault events. Finally, the results from three different types of short-circuit faults are summarized and compared for several PM machine configurations to provide information that will be helpful for choosing the best machine for new applications. Experimental results are provided for constrained ASC fault conditions that build confidence in the models and their predictions.