Life Testing of High-Value Annular Form Factor DC Link Capacitors for Applications with 105 o C Coolant

The SBE Power Ring Film Capacitor TM offers the advantages of high capacitance value, low equivalent series resistance and inductance, and minimal temperature rise using polypropylene film. Recent work has addressed optimization of the Power Ring for automotive DC link applications with funding from the US Department of Energy. Under this program, life testing of over 600 1000 µF capacitors has been performed to validate the design for coolant temperatures in the 105 o C regime. This paper presents the methodology for the test program and describes the experimental apparatus. Results are discussed for testing to date, which has provided two million unit hours of exposure with only two failures observed after an initial pre-testing run which identified parts built with defective film.