Abstract : Using frequency converters (VDCs) to regulate the speed of fan-type machinery to adjust air volume is of great significance for energy conservation, building a resource-saving society, and improving economic efficiency. This article, through an economic analysis of the application of VDCs in fan control systems, further clarifies the enormous energy-saving potential of VDC control for fans and points out the direction for energy-saving retrofitting of fans. Keywords : energy saving; economic efficiency; variable frequency speed regulation; energy saving. Variable frequency speed regulation is the most ideal solution among AC motor speed regulation methods. Using VDCs to regulate the speed of fan-type machinery to adjust air volume is of great significance for energy conservation, building a resource-saving society, and improving economic efficiency. However, in the past, due to various reasons, such as the price, quality, and capacity constraints of VDCs, it has not been widely used. In recent years, with the rapid development of the IC industry, the price of VDCs has dropped significantly, reliability has increased, and capacity has increased (reaching 400KW), leading to a significant increase in the use of VDCs. I. Theory of Variable Frequency Speed ​​Regulation for Energy Saving A fan is a device for transporting gas. Its structure and working principle will be explained using a fan as an example. Using a frequency converter to control the fan is an energy-saving method that reduces aerodynamic forces. Compared with the commonly used method of controlling airflow by adjusting dampers, it has a significant energy-saving effect. Figure 1 illustrates its energy-saving principle: [b][align=center]For details, please click: Economic Analysis of the Application of Frequency Converters in Fan Control Systems[/align][/b]