Medical X-ray appliances use high-voltage power supplies that must be able to work\nwith very different energy requirements. Two techniques can be distinguished in X-ray medical\nimaging: fluoroscopy and radioscopy. The former involves low power radiation with a long exposure\ntime, while radioscopy requires large power during short radiographic exposure times. Since the\nconverter has to be designed by taking into account the maximum power specification, it will exhibit\na poor efficiency when operating at low power levels. Such a problem can be solved by using a\nnew multilevel LCC topology. This topology is based on a classical series-parallel resonant topology,\nbut includes an additional low-voltage auxiliary transformer whose function depends on the X-ray\ntechnique considered. When radioscopy operation is selected, the transformer will allow the power\nto be shared between two full-bridges. If fluoroscopy mode is activated, the auxiliary full bridge\nis disconnected and the magnetizing inductance of the auxiliary transformer is used to increase\nthe resonant inductor in order to reduce the resonant currents, thus improving the efficiency of\nthe converter.
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