CISPR 25 HV/LV Coupling Attenuation Measurements with R&S®ELEKTRA

Electric (EV) and hybrid electric (HEV) vehicles have both high-voltage (HV) and low-voltage (LV) electric systems. The LV systems are typically unshielded (infotainment, lighting, sensors etc.) and HV systems (battery packs, inverters, electric motors etc.) are shielded. The HV systems ranges from 400 V to 1500 V and the LV system ranges from 12 V to 48 V. The switching operations in HV systems can generate significant electromagnetic noise that may couple into the LV system and degrade performance or cause malfunctions.

The HV/LV coupling tests, as defined in CISPR 25, specify the test setup in which HV systems are modified to inject electromagnetic disturbances at predefined levels, depending on the classification of the equipment under test (EUT). These tests also outline methods for measuring the coupling attenuation between HV and LV systems. Additionally, they define procedures for measuring conducted emissions (current and voltage) on LV systems during HV system operation. Furthermore, the standard includes methods to measure radiated noise (electric field) emissions generated when operating HV Systems.

The HV/LV coupling tests are emission tests in line with CISPR 25 but some require an immunity test setup to inject disturbance into the system. This application note describes how to set up R&S®ELEKTRA and perform HV/LV coupling attenuation measurements.