Calorimeter evaluation of inverter grade metalized film capacitor ESR

The capacitor industry requires fast and accurate characterization of component equivalent series resistance (ESR) and capacitance (C). In a manufacturing setting the measurements must be very fast, repeatable and high quality for use in process control, data collection and monitoring, plus for printing on the component SKU label. The fastest characterization testing is done electronically using pulse techniques and these must provide accurate assessment of the true parameter values. In this work a calorimeter method was developed to corroborate ESR values obtained using a recently developed electronic ESR characterization method at ORNL. Calorimeter measurements are very slow, tedious and subject to error if chamber inlet air is not properly conditioned. It was found that the provisional coplanar bus plate used for mounting a power ring high current capacitor introduced frequency dependence in ESR results that electronic measurement techniques did not incur. The calorimeter method lends itself well to parameter characterization under real world application conditions at rated current, frequency and wave shape ¹.