Abstract: To address the issues of high energy consumption, low regulation accuracy, and insufficient protection mechanisms in fixed-frequency operation of traditional fans, an automatic control system based on fan frequency converters is designed to achieve intelligent, efficient, and safe operation of fans. A hierarchical architecture is adopted for design, with PLC as the core control unit and frequency converter as the execution core. Multiple types of sensors are used to complete on-site data collection, and hardware adaptation design and modular software programming are carried out. The core adopts PID control algorithm, and dual manual/automatic modes and multiple interlock protection mechanisms are set. The pressure control error of the system is≤±5%, the response time is≤2 s, and the energy consumption is reduced by more than 30% compared to the traditional system. The system can operate stably without faults for 720 hours continuously. The regulation accuracy and scalability are excellent. This system can effectively replace the traditional fixed-frequency fan control system and is suitable for industrial scenarios such as metallurgy, providing technical support for the intelligent and efficient development of industrial production.