Losses evaluation and techno-commercial impact of varying aluminium material requirements in High Power Rectifiers

An accurate evaluation of the energy losses is a crucial factor for every device dealing with high currents. This thesis investigates the power dissipation of water-cooled High Power Rectifiers, which require an accurate knowledge to optimize the mechanical structure, choose the correct materials, properly model and design the cooling system and finally fulfill customers’ efficiency requirements. The analysis explores different methodologies, ranging from model simulations to physical measurements. Their advantages and drawbacks are compared using multiple criteria to decide which is the most reasonable approach to employ. Due to the uncertainty of the available measurement methods, paired with the required efforts for an appropriate test setup, physical measurements were disqualified for this work. The focus was instead put on the digital simulation of the rectifier losses. Two approaches investigated in more detail are the impedance parametrization of the rectifiers components to build an equivalent electrical circuit model and a dynamic electromagnetic 3D analysis of a simplified rectifier structure with the Finite Element Method. A cross validation of the results has been performed to properly evaluate the reliability of the results. As a conclusion, the parameterized model has been confirmed and selected as an appropriate and practical approach to investigate a full portfolio of rectifier variants. In a final step, the implemented models have been used to perform pre-studies on the technical impact varying conductivity and geometry of specific rectifier components and put in perspective to commercial considerations.