The thesis addresses development of isolated DC/DC converter for use in medical electrical devices. Development includes design, assembly and testing of the converter. In introduction are presented the motivation to build such a converter and ways to achieve sufficient galvanic isolation. Introduction also includes presentation of LLC topology, which is the topology of the discussed isolated converter.
In the following chapter we study the operation of LCS702 regulator and the effects of electrical elements in the LLC converter circuit on the operation of the converter. We continiue with component selection, designing and fabricating the transformer and the printed circuit board (PCB). The development of the converter relies heavily on the datasheet of the integrated circuit LCS702, which is used for controlling LLC converters. The datasheet includes the schematic of the LLC converter circuit, which we adapted to meet the requirements for higher galvanic isolation.
The final chapter covers the presentation of measurement results. We started with load tests at the anticipated 24%, 48%, and 96% of output power, corresponding to 36 W, 72 W, and 144 W, respectively. It turned out that under load, the output voltage of the converter collapses. Consequently, the actual output power is lower than anticipated. At the highest load, the converter shut down after a short period. The maximum short-term achieved output power was 116 W, while the maximum long-term achieved output power was 61 W.
As part of EMC testing, we measured conducted and radiated emissions. The measurements showed that the converter does not meet EMC requirements. We recommended improvements for the converter that could make it meet the EMC requrements. We did not measure the galvanic isolation of the converter.
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