Digitally Adjustable Step Up Converter

DC-DC converters are electronic devices used to change DC electrical power efficiently from one voltage level to another. Complex systems like an industrial printer require accurate high voltage levels to let the print head nozzles spit out the ink in the proper way, according to the pattern to be printed. Creadigit, product of System S.p.a, is a high precision printing system used in decorations for ceramic products. It is actually powered by a couple of rack mounted AC-DC converters, which offer simple powering solution at low cost. Nevertheless, the total system efficiency can be sensibly increased with the introduction of a DC-DC Step UP converter in place of the AC-DC supply. This thesis is focused on the analysis, modeling, design and implementation of a Boost converter for such application. One project goal is to provide the converter the ability to digitally adjust the output voltage according to the requirements of each printing head, thus leading to a consistent power saving of the entire system. The work structure is so arranged: first of all, it is explained the architecture of the printing system and the inkjet printing mechanism so as to understand why high voltage supplies are required. Secondly, the power amplifier system is analyzed through simulation in LTSpice environment. During these simulations, there will be an analysis of potential power savings introduced by the adoption of the adjustable DC-DC converter. It follows the Boost converter theory, necessary to understand the operation of the key element of this project. Moreover, a detailed study of the complex world of capacitors is developed. In fact, the output capacitor selection is one of the trickiest part in the design of a switching DC-DC converter. In this thesis, a short theoretical study about EMC in SMPS converters is accompanied by simulations that could anticipate the results of in-field studies. In the end, some results of a first DC-DC converter prototype will be presented.