MODELING OF A MODULAR MULTILEVEL CONVERTER WITH NON-IDEAL SWITCHING COMPONENTS

A Modular Multilevel Converter (MMC) is an innovative topology that has the potential to become widely used in all segments of industry, production, and power transmission, particularly at high and medium voltage levels. The transmission of electricity generated in offshore wind farms and HVDC systems are just some of the applications of this type of converter. MMC has been relatively well studied in terms of design and control, but very little research has been dedicated to the calculation or measurement of losses and efficiency. This paper focuses on conducting such a study, which can enhance the understanding of MMC advantages and provide further motivation for its application. In the paper, a converter model was formed using real switching components, enabling a detailed loss calculation. In addition to the efficiency, which is one of the key criteria for comparison with conventional topologies, the power loss value is also important from the perspective of designing cooling systems and, consequently, the complexity, total mass, and dimensions of the converter. Based on all the above, the aim was to propose an analytical model for loss calculation based on switching component information provided by the manufacturer. The results of the analytical calculation were compared with values previously obtained through loss modeling in the PLECS software package, confirming the accuracy of the presented analytical model. The contribution of the paper lies in the formation of a model that allows the calculation of MMC losses based on data available in the manufacturer’s catalog, which can be applied, without loss of generality, even in the case of a large number of submodules.