Current discussions about simulation and its potential uses often relate to the digital twin. Although simulation certainly plays a key role here, it offers great potential in other areas as well, such as the design and optimization of high-voltage wiring systems. At LEONI, we place enormous importance on system level in order to consider interactions within the entire HV wiring system. This article discusses the role of the electro thermal simulation method in the form of thermal networks, and shows how LEONI applies its existing know-how to support customers so that they can benefit from this method already during the pre-development stage.
Limits of classical dimensioning methods
In the simplest case, connectors and cable cross-sections are selected based upon derating curves and time-current characteristic (TCC) plots. While the former provides an accurate statement of the continuous current-carrying capacity, TCC plots can be used to evaluate current-carrying capacity based on a single current pulse. These established diagrams allow for a quick (initial) estimation of current-carrying capacity for continuous and one-time pulse currents.
In a vehicle, however, the current load consists of a combination of such currents. This means that the resulting temperatures can no longer be accurately derived from these diagrams. Thereby highlighting the clear limits of the usual dimensioning methods.
In addition, most high-voltage wiring systems are shielded, so shielding currents are to be expected in the HV wiring system. These additional ohmic losses, caused by induced or vagrant currents, influence the current-carrying capacity.
Classic diagrams are simply insufficient for taking into account the aforementioned effects and the thermal interaction of cables, connectors, and components. This is where the thermal network approach comes in.