Precision calorimetry for the accurate measurement of inverter losses

Abstract

High precision calorimetry permits the direct measurement of losses in power electronic systems. This paper describes improvements to the design of a double- jacketed, closed type calorimeter in order to make these measurements. Calibration tests have confirmed that the new design can measure losses to an accuracy of better than 0.5 W in 200 W. This calorimeter has been used to verify the accuracy of models for inverters for use in variable speed drives for domestic appliances. Verification has been undertaken at a range of switching frequencies and confirms the ability of the models to predict inverter performance without recourse to physical prototypes.