1 Introduction Fans and pumps are the main loads that consume electrical energy. Because their loads vary greatly while the speed of the motor remains constant, it results in a situation where "a large horse pulls a small cart," wasting a lot of energy. AC frequency converters not only have superior speed regulation performance but also have significant energy-saving effects. Practice has proven that large and medium-sized cage induction motors driving fans and pumps can save an average of about 40% energy if frequency conversion speed regulation technology is used. This article introduces the application of frequency converters in boilers and explains their energy-saving effect. 2 Energy-saving principle of frequency conversion speed regulation for fan loads In industrial boiler speed control systems, frequency converters are mainly used for blowers, induced draft fans, water supply systems, and slag removal systems. Their main purpose is to save energy. The speed formula of a converter asynchronous motor is: n=60f÷P（1一s） (1) From equation (1), it is known that the power supply frequency is proportional to the speed, that is, changing the frequency can change the speed of the motor. Theoretically, air volume is directly proportional to the first power of rotational speed, air pressure is directly proportional to the square of rotational speed, and shaft power is directly proportional to the cube of rotational speed. Test data for adjusting the damper and adjusting the rotational speed are listed in Tables 1 and 2, respectively. As can be seen from Tables 1 and 2, adjusting the rotational speed has a significantly more significant energy-saving effect compared to adjusting the damper (tested fan motor PMN=1.6kW, nMN=1430r/min). 3 System Modification Scheme and Economic Effects [b][align=center]For details, please click: Application and Energy-Saving Effect Analysis of Frequency Converters in Boiler Control Systems[/align][/b]