With the rapid development of electronic technology, computer technology, automatic control technology, the power output of technology, AC motor control technology has made breakthrough progress, has become a primary tool in today's energy-saving and improving the environment, promoting technological progress, It has become an inevitable trend. Significant energy savings and superior regulation performance, make energy-saving inverter technology application in China coal mine more and more widely, technology is more mature. High-capacity, multi-functional, high reliability drive in coal production has been widely promoted and applied, in order to save a lot of power coal mines, especially in the fluid class load, and its energy-saving rate of 20% to 60%. Frequency control principle is: the use of an inverter motor to achieve true soft start and smooth speed control, the use of inverter control to improve input power factor, the base frequency is the constant torque output, the output power with the speed of change.