Capacitors for high temperature DC link applications in automotive traction drives: Current technology and limitations

Recent years have seen an increase in the use of electric traction drives for automotive applications. This field is rapidly advancing thanks to the drive for greater power density in such drive systems, and this can place additional demands on the DC link capacitor. This component must maintain high reliability and long life, while storing large amounts of charge at high voltage, but the constraints it introduces are often not considered fully. The aim of this paper is to provide an overview of this field at the present time, which is currently lacking in the literature; identify limitations of current technology; and provide impetus for future research. Current dielectric materials and their suitability for this application are assessed and compared, and then the direction of current research into novel materials is investigated.