Abstract This paper introduces the basic concepts of electromagnetic compatibility (EMC), the propagation modes and formation paths of the main interference sources in the electrical control system of spunbond nonwoven fabric, the impact of interference on the system, and countermeasures. Keywords Electromagnetic compatibility (EMC), PLC, frequency converter, grounding technology 1 Introduction The spunbond nonwoven fabric production line has a high degree of automation. The use of industrial control computers, a large number of PLCs and frequency converters complicates the electrical system interference problem (the network structure of the control system is shown in Figure 1). In some of our early projects, during commissioning and operation, unexplained shutdowns, false alarms due to incorrect inputs, and malfunctions sometimes occurred. The main reason for this was interference causing program calculation errors or signal errors in control components. Long-term adverse interference environments can also easily damage components or reduce their service life. Therefore, the corresponding anti-interference design technology (electromagnetic compatibility, EMC) is becoming increasingly important in the design of control systems. Electromagnetic compatibility (EMC): The ability of equipment or system to operate normally in an electromagnetic environment without causing unacceptable electromagnetic interference to anything in that environment. This paper discusses the main related factors based on the design characteristics of the electrical control system of our production line. 2. Propagation Modes of Main Interference Sources in the System The production line has a large number of frequency converters, especially the high-power supply and exhaust fan frequency converters, which can generate significant high-order harmonics, causing strong interference to other equipment in the system and are the main source of interference noise. High-order harmonic interference from frequency converters is divided into conducted interference, radiated interference, and induced interference, as shown in Figure 2. 2.1 Conducted interference propagates through the power network. Because the input current contains odd-order harmonic components, it will distort the network voltage. When there are many frequency converters with large capacities, it can easily pollute other equipment; conducted interference generated at the output end significantly increases the copper and iron losses of the directly driven motor, affecting the motor's operating characteristics. 2.2 Radiation interference, i.e., the interference source couples the interference to the affected object through spatial propagation, is the main propagation mode of high-frequency harmonic components. (Read full text : Electromagnetic Compatibility Design of Spunbond Nonwoven Fabric Electrical Control System)