Metalized film capacitors with high energy density for rail vehicles

This paper describes metalized film capacitors with high energy density that have been developed for railroad traction motor controls. In the late 1980s to early 1990s, aluminum electrolytic capacitors were generally used for the inverters to drive and control traction motors since they were smaller and lighter than metalized film capacitors. New metalized film capacitors have been developed that are equivalent in size and superior in performance to the aluminum electrolytic capacitors. The new metalized film capacitors have been operating successfully on railroad traction motor controls for approximately 4 years. The paper presents mainly how the compact size has been achieved on the new metalized film capacitors