The Dynamic Electromagnetic Distribution and Electromagnetic Interference Suppression of Smart Electric Vehicle 2019-01-1061
Smart electric vehicles need more accurate and timely information as well as control, which depends on great environmental sensors such as millimeter-wave radar. In this way, the electromagnetic compatibility of whole vehicle confronts more serious challenges. Thus, this paper studies the electromagnetic distribution and electromagnetic interference suppression of smart electric vehicles with the followings including:
Firstly, the millimeter wave radar is modeled and optimized. Micro strip patch antenna, with small size, light mass and low cost, is used as array element of array antenna. Millimeter wave radar is modeled and simulated step by step from array element to line array to surface array. It turns out that surface array antenna has higher gain and narrower bandwidth compared to array element and line array. Then the Cross Shape - Uniplanar Compact - Electromagnetic Band Gap (CS-UC-EBG) structure is deployed to optimize its electromagnetic characteristics, based on finite time domain difference model theory.
Secondly, considering that the most of electromagnetic interference (EMI) in electric vehicle comes from drive system, the conduction and radiation model of electric drive system is established on the basis of analyzing mechanism of EMI in electric drive system,, which is verified by corresponding experiments. Besides, the effect of motor torque and speed on electromagnetic radiation of drive system are studied. It turns out that the effect of torque and speed are realized by influencing duty ratio of IGBT. The higher the duty ratio is, more serious the electromagnetic interference is.
Thirdly, according to requirements of vehicle electromagnetic modeling, DC/DC, millimeter wave radar, drive system and high-voltage cables are modeled as excitation sources to simulate the dynamic electromagnetic distribution of vehicle. Finally, aiming at overshoot frequency point in whole vehicle radiation test, the shielding wiring and common mode choke are used to suppress EMI to meet requirements.