Experimental Investigations on an Autonomous Load Shutdown Mechanism in Respect to Voltage Stability in Automotive Power Nets

The power demand in 14V automotive power nets has steadily increased in recent years. On the one hand, more and more comfort electronics have been integrated. On the other hand, previously hydraulically driven chassis control systems have been replaced by electrically powered systems in order to increase efficiency. This trend has led to a drastic increase of the load´s combined peak power. For this reason, voltage stability has become an important design criterion of automotive power nets. This paper experimentally investigates the influence of an autonomous load shutdown mechanism on voltage stability. The mechanism temporarily shuts down non-safety-critical heating systems with high continuous power consumption, e.g. seat heaters. This mechanism is implemented on a generic ECU hardware. In order to achieve the most realistic behavior of the system, the hardware is integrated into a 14V power net test bench, consisting of a car chassis and the wiring harness. Concluding measurements reveal that this mechanism is able to increase the terminal voltage at the most critical positions of the power net by about 1V.