Data-driven Modeling and Simulation of Thermal Fuses

Increasing power requirements in vehicles and the integration of safety-critical electrical systems present a challenge for electrical distribution systems in terms of reliability, packaging, weight, and cost. In most cases, the wire protection device is a thermal fuse. It’s the key element, as it determines the reliability of the short circuit detection, the immunity against false tripping, and the wire diameters. Thermal fuses are used, due to their low cost and their robust design.In vehicles, the current profiles become more and more complex, so that the description of the fuse tripping behavior, which is based only on steady-state currents, is not sufficient. The presented approach is a data-driven fuse model. Therefore a set of thermal fuses were measured in an experimental set-up with precise temperature measurement.The thermal step response can be determined for any allowed current value and be described by a superposition of four first order lag (PT1). Due to the non-linear dependence between the applied current and this response function, the model becomes more complex and must be based on several measurement data sets for different currents.Based on a recursive approach, a new generic model has been developed which can accurately be parameterized for various fuse types and diverse nominal currents and allows the calculation of the maximum temperature within the fuse for any given current-time profile. This paper describes the measurement set-up, the model and its parameterization method, a tool to simulate the thermal behavior and a comparison of calculated and experimental data.