The development of noise, vibration, and harshness (NVH) sensors for automotive applications, in the past, has been without regard for high-voltage (HV) electro-magnetic (EM) fields, which are now present in electric vehicles (EV) and hybrid electric vehicles (HEV). Consequently, there are concerns about what influence or effects HV EM fields impose on microphone and accelerometer signals when implemented for operational testing of EVs or HEVs. There has been little available information on the subject, but this 30-minute Webinar offers insight and guidance based on the results of a new study.
To address and understand the influences of EV HV EM fields on microphone and accelerometer signals, PCB Piezotronics Inc. commissioned a study to assess these effects on a pure EV. The goal of this testing is to determine the effects on NVH sensors and which, if any, type of sensor performs better under EM fields seen in an EV. Ten different models of PCB® NVH sensors, including several cable types for some of the sensors, were evaluated locally to various HV EM field sources during road tests of an EV. The microphone and accelerometer signals were recorded along with signals from adjacent transducers that measure the EM field strength.
Assessment of the influence of the HV EM fields is based on the coherence function between the NVH sensor signal and the corresponding EM field transducer signal – where higher coherence values indicate a higher influence of HV EM fields on the NVH sensor signals. The results show that certain locations on a vehicle may affect the accuracy of the measurement. They also indicate that certain types of accelerometer designs yield a better signal quality result in EV NVH testing applications.
An audience Q&A follows the technical presentation.