Optimized Design the Shell of Film Capacitor Used in Controller Considering Surface Roughness

The requirements of volume power density imposed by motor controllers limit the heat dissipation area of capacitors, thereby posing higher demands on the high-temperature performance of DC-Link capacitors. Due to the majority of the heat generated in capacitor core is dissipated into the ambient environment through the shell, optimizing the shell of capacitor to increase the heat dissipation area can effectively reduce the hotspot temperatures of the capacitors. This paper proposes a method to reduce the hot spot temperature of film capacitors by optimizing the roughness of the capacitor shell. Corresponding characterization methods for capacitor shell roughness are proposed, and the impact of roughness optimization on hotspot temperature of capacitor is analyzed. The effectiveness of the proposed method is validated through an optimization example of a 110μF capacitor.