DC link capacitors for traction SRM drives in high temperature automotive environments: A review of current issues and solutions

Recent years have seen an increase in research into switched reluctance machines for automotive traction applications, driven by the cost and scarcity of permanent magnet materials. Such machines increase the demands on the DC link capacitor, which must maintain high reliability and long life while storing large amounts of charge at high voltages. The aim of this paper is to provide an overview of this field at the present time, which is currently lacking in the literature, and provide impetus for future research. The limitations of current technology are identified, both in terms of dielectric materials, control and circuit topology. Current dielectrics and their suitability for this application are assessed and compared. Then methods are illustrated which could reduce the requirements of the DC link capacitor from the perspective of control and circuit topology, which benefit the system design in cost, weight and efficiency.