CAN Signal Processing for EMI Reduction Cooperating with Switched-Mode Power Supply

Electromagnetic interference (EMI) on wired communication systems caused by a switched-mode power supply is often remarkable in practice. The EMI undermines the performance of the communication and robust operation of the system. In this paper, a test system where a buck converter and a controller area network (CAN) communication system are integrated enables to measure noise waveforms and analyze the EMI mechanism in the time-domain. The simulation model of the system also performs verification of the mechanism. In the system, the DC bus cables connected to the converter are closely adjacent to the communication cables and they have electromagnetic couplings. Hence, when the converter generates a switching noise in the DC bus, an induced noise happens in the communication cable, which results in communication failure. Based on the EMI mechanism, a noise elimination method is developed and implemented to the CAN of the test system to prevent communication failure. The proposed method is feasible in the converter controller and it does not require additional hardware components to reduce the communication failure. Through experimental verification, the proposed method enables to reduce communication failure.