Suppression Methods for Electromagnetic Interference of the DC Motor

Abstract

The basic principle of electromagnetic interference, test methods, and suppression measures for DC motor are studied and analyzed. We select 18V/5A DC motor as the research object, and test full-frequency interference characteristics of the conducted and radiated interference. By analyzing the test data, we design and add the X2Y filter to the DC motor, and test its all-frequency characteristics. The results show that the X2Y filter can effectively suppress the conducted and radiated electromagnetic interference of DC motor, which can greatly enhance the electromagnetic compatibility characteristics of the DC motor. 0 Introduction At present, the people's living environment has been surrounded by electromagnetic environment, at the same time, with the rapid growth of population, a large number of electronic, and information equipment have come into people's lives. Many electronic components are incorporated on these equipments, which would be interacted with each other by electromagnetic radiations and conducted signal, making the electromagnetic environment worse; meanwhile, it also poses a threat to the communication, computer and electronic system. Electromagnetic Compatibility (EMC), it refers to the coexistence state of the electrical and electronic equipment that can perform their functions in a common electromagnetic environment [1] , which requires that these various devices in the same electromagnetic environment can work without disturbing each other and achieve "compliant" status. Because the DC motors are widely used in household appliances and electrical equipments, it is important to study the electromagnetic compatibility of the DC motors. In this article, we select 18V/5A DC motor as the research object, and its test EMI characteristics exceed the standard limit. Therefore, we design and add the X2Y filter to the DC motor. The results show that the X2Y filter [2] can significantly reduce the level of the electromagnetic interference [3] and enhance the electromagnetic compatibility of the DC motor. 1 The basic principle of electromagnetic interference EMI (Electromagnetic Interference) is "Electromagnetic disturbance caused by device, transmission channel or system performance decline". In the cable harness, multi-conductor transmission line, and in close proximity of the wires of the printed circuit board, there is a variety of electromagnetic interference, and the running motor also will produce strong electromagnetic interference, causing worsening phenomenon of the device or system. Moreover, it can interfere with the normal operation of other equipment, which can lead to disastrous chemical accidents. So the study of the motor electromagnetic compatibility problem is particularly important. 1.1 The three elements of EMI No matter complex system or simple equipment, any major scientific content of electromagnetic compatibility all revolve around three elements: electromagnetic interference source, route of transmission and sensitive equipment. As shown in Fig.1, interference sources are accompanied