Abstract : This paper discusses the speed requirements of AC hoists during deceleration and crawling sections, as well as the existing problems of current equipment. It proposes an AC-DC-DC converter scheme to solve the power supply issue for dynamic braking, and an AC-DC-AC frequency converter scheme to address the low-speed crawling requirements. The system structure is given, the control circuit theory is analyzed, and finally, the structure of the control software and the main program flowchart are presented. Keywords : Hoist; Converter; Frequency Converter 1 Introduction Currently, most hoists in various mines across the country use an AC wound-rotor asynchronous motor rotor series resistance speed control scheme. This speed control scheme lacks braking torque in low synchronization states, while the hoisting process requires the drive system to operate in braking state (lowering heavy objects) or motor state (lifting heavy objects) during deceleration and crawling sections. Currently, low-frequency power supplies are often used to solve these problems, and these low-frequency power supplies employ a thyristor AC-AC direct frequency converter scheme. This scheme has the following problems: low power factor, large harmonic components in the output voltage; complex control circuit, especially the positive and negative phase commutation, which is difficult to control. Currently, the reliability of such products in China is relatively low. This project employs AC-DC-AC pulse width modulation (PWM) frequency conversion technology to address the requirements of low-speed crawling (electric operation). When the hoist is in braking mode, a dynamic braking scheme is used, converting the AC-DC-AC converter circuit to an AC-DC-DC controllable PWM state to control the stator DC excitation current, overcoming the problems of the thyristor AC-AC direct frequency conversion scheme. 2. Drive Scheme The mine hoist is an important piece of equipment in mine production, and its structure is shown in Figure 1. [b][align=center]For details, please click: Research on Converter Power Supply for the Reduction Section of Mine AC Hoist[/align][/b]