Protective and / or diagnostic device for multi-voltage vehicle electrical system, multi-voltage vehicle electrical system and method for operating a multi-voltage vehicle electrical system

摘要

A protection and / or diagnostic device (1) for a multi-voltage vehicle electrical system (10), the multi-voltage vehicle electrical system (10) having a first sub-network (11) which can be acted upon by a first voltage, and at least one further sub-network (12) with at least one further voltage being acted upon, wherein the first voltage is higher than the at least one further voltage, and wherein the first (11) and the at least one further subnetwork (12) have a common ground connection (GM), it is proposed wherein at least one further ground terminal (GG) is provided, are associated with the measuring means, which are adapted to measure a current flow through the at least one further ground terminal (GG), and diagnostic means (2) are provided, which are adapted for Basis of the measured current flow over the at least one further ground terminal (GG) as a function of at least one operating state of the multi-voltage On-board network (10) to diagnose a fault in the common ground terminal (GM) and / or the at least one further ground terminal (GG).