RF coupling between high-voltage and low-voltage systems on a system and component level

On-board networks with different voltage levels are applied in vehicles equipped with an electrical drive system. Voltages in the range of several hundreds of volts are used in the traction (high-voltage; HV) network. Conventional electronic devices are connected to the low-voltage (LV) network. In the automotive industry, where HV components containing sensors, contactors and communication interfaces, etc., are used, both voltage levels are present. As a result, several coupling paths exist between the LV and the HV level which contribute decisively to the electromagnetic behavior of the complete vehicle. In order to obtain knowledge about the electromagnetic compatibility (EMC) characteristic as completely as possible during the component test, it is useful to extend the existing CISPR 25 test setups by measurement routines focusing on the HV/LV coupling behavior. In the following, the investigation of the HV/LV coupling behavior of a complete HV vehicle system is shown. The measurement results are compared to those of a component test setup based on the CISPR 25 standard.