Abstract : This paper introduces the working conditions and control process of coal mine hoists, and theoretically analyzes the basic principles of variable frequency speed regulation and energy saving of hoists. Through examples, it introduces the method of energy-saving retrofitting of hoists using frequency converters, and shares experience in selecting frequency converters for mine hoists. Keywords : Frequency converter; Variable frequency speed regulation; Hoist; Energy saving 0 Introduction With the rapid development of power electronics and microelectronics technologies, the performance of frequency converters has also greatly improved. Variable frequency speed regulation has significant energy-saving effects on fan and pump loads, and has excellent control characteristics such as shock-free start-up and soft shutdown. Therefore, frequency converters have been widely used in the fields of fan and pump control in metallurgy, power, petrochemical, and civil construction. Coal mine production has special environmental conditions and special safety requirements; therefore, the application of frequency converters in coal mines started relatively late, and currently, there are relatively few explosion-proof frequency converter products that meet the safety production requirements of coal mines. With the development of China's economy, increasing production, reducing consumption, and improving efficiency in coal mines have been given high priority, making energy-saving retrofitting of equipment imperative. 1 Overview of Mine Hoisting Mine hoists are equipment that operate under heavy and complex conditions. Therefore, the drive device of the hoist is required to be able to adapt to frequent starts, stops, speed adjustments and phase changes, and to achieve heavy-load starts. Under the premise of ensuring the safety and reliability of the hoisting equipment, it operates according to the designed hoisting speed diagram. Mine hoisting systems are divided into vertical shaft hoisting systems and inclined shaft hoisting systems. Vertical shaft hoisting systems have large hoisting capacity and heavy load, and generally use high-power motors. Inclined shaft hoisting systems are used in small and medium-sized mines. When the power is above 220 kW, a 6 kV, YR type high-voltage motor is selected; when the power is below 200 kW, a 380V (660 V), YR type low-voltage motor is selected. (1) Hoisting Speed ​​Diagram Mine hoisting refers to the transportation system that hoists coal and lowers empty cars or materials from the bottom yard to the surface unloading point. The hoisting distance and hoisting interval are fixed, and the operating speed diagram in each interval is also regular. The hoisting speed diagrams for vertical shafts and inclined shafts differ. Due to space limitations, this article only uses the hoisting speed diagram of the double-hook tandem car hoisting system in the flat yard of an inclined shaft to illustrate the operating principles of coal mine hoists. Download the full text PDF: Application of Variable Frequency Speed ​​Control Technology in Mine Hoists