A2Z Consulting

A traditional thermal design process of an air cooled power electronics cabinets usually involves several hierarchy levels starting from the single component level and going up to the full system/cabinet level. Simplified methods such as flow network analysis are usually used for the cabinet level thermal designs. Those methods provide the flow rates/velocity, pressures and temperature distribution throughout the cabinet. However, the simplified nature of such methods requires over-simplification of the air flow paths geometry. To account for the complexity of the actual flow paths, empirical data, obtained from testing/past experience is used. Obtaining this empirical data requires construction of prototypes and is time/cost consuming.
3D CFD simulations of the whole cabinet assembly/sub-assemblies, provides a faster alternative for design verification in early design stages. The CFD simulations allow visualization of the actual flow paths for complex geometries and provide great insight of the flow/thermal behavior of the design without the need to construct an actual prototype. Using CFD simulations, one can predict the pressures, temperatures and air velocity distribution throughout the cabinet and use the results for optimization of the design.  The simulations results can then be used as inputs for more detailed simulations of lower hierarchy levels (e.g. simulation of single PCB board or single passive component). In addition, CFD simulations can be used to obtain the required empirical data to be used in the more simplified traditional methods (e.g. pressure drop coefficient of flow path through a complex component).
During this project, an extensive 3D CFD analysis of air cooled Medium Voltage VFD was done and its design was optimized accordingly.