Prediction of conducted RFI emissions in BLDC motors for automotive applications

With the proliferation of electronic devices in automobiles, an emphasis has been placed on EMC issues for among others reasons, safety. The EMC design cycle can be lengthy, with the mitigation of conducted RFI emissions still largely a trial and error process. The use of a virtual motor and drive model can be used to shorten this process. In the modeling of conducted RFI emissions, an accurate model of motor and drive is necessary. Furthermore, a representative method of characterizing the conducted RFI spectrum is required. A virtual motor model for an electronically commutated engine cooling fan motor and drive is presented to predict conducted RFI emissions up to 30 MHz. This model forms the basis of a method that may be used to predict conducted RFI emissions on other motor and drive types.