Calorimetric Power Loss Measurement of a Small Power Converter
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Sähkötekniikan korkeakoulu | Master's thesis
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EST - Master’s Programme in Electrical Engineering
AbstractMiniaturisation - is the key word in technology today and the general trend in all industries is to seek for smaller and compact electrical and magnetic components. With the increase in energy density, the loss density does too, and so does the need to achieve greater measurement accuracy of device losses. Calorimeters are the way to accomplish this effectively, as proven by the prevailing calorimetric watt-meters for electrical systems. The undertaking of this thesis work was to build a simple yet accurate calorimetric system to measure power losses in highly efficient power converters and similar small devices belonging to a power class of <1 kW. An improved closed, water cooled calorimeter with flow control and input water temperature control has been implemented, as an alternative to the accepted, yet complicated double jacketed calorimeter. The balance tests with the calorimeter yielded the calibration curve, which was followed by the actual test with a 0.75 kW frequency converter. From the power losses measured by the calorimeter, the tested device was confirmed to have a high efficiency of 97%. The calorimeter that was built is characterised by low flow rates and can measure loss powers in range of 25 W - 520 W with an accuracy better than 1.5% for power losses <50 W.
Thesis advisorRasilo, Paavo
low power loss, accurate loss measurement, calorimeter, small power converters