Simulation of Shield Current in Automotive High Voltage Systems

Abstract

In automotive high voltage (HV) systems, the switching operation of a power electronic converter causes current and voltage ripple in the frequency range of [10 Hz–150 kHz]. Automotive system engineering provides requirements that define the behaviour of HV components in that frequency range. Shielded HV cables must stand induced current in the frequency range of the ripple. One of the relevant requirements is the maximal current stress of the shielding. Several individually shielded cables are used in automotive HV systems, and these shields influence differential mode disturbance currents, such as the ripple current from the traction inverter. In this work, we provide a model and an analysis of shielded cables integrated into an automotive HV system in relation to system-level design parameters. To fill the gaps of existing research, we focused on two questions: How do design parameters influence the shield current value in the frequency range of the current ripple in a vehicle, and how should a shield and connector system be designed with respect to shield currents over the life-time? We applied analytical and simulative solutions to these problems through a co-simulation approach on the architecture of a real vehicle. The presented approach extends existing research by integrating simulations and vehicle measurements to life-time prediction. Moreover, the proposed methods enable the replacement of the state-of-the-art constant 10 A requirement to a driver profile based predicted shield current requirement on individually shielded HV cables in battery electric vehicles (BEV).