The rapid development of AC speed regulation technology has expanded its application range. The application field occupied by DC speed regulation has been replaced by AC speed regulation gradually; In the original super capacity, high speed and bad environment, which is difficult to apply, AC speed regulation has played a role; The field of using AC drive but not speed regulation, through the use of AC speed control drive, greatly saves energy. At present, AC speed regulation has been widely used in the transmission field of all sectors of national economy.
Metallurgical machinery is mainly used for the main drive of the rolling mill and the blower of the blast furnace. As we all know, the main drive of rolling mill is a high-performance electrical transmission system, some require large capacity, low speed, strong overload capacity, some require high speed control accuracy, etc. in the past, DC speed control has been the leading position, and is now being replaced by AC-AC frequency conversion speed regulation.

Electric traction is mainly used for electric locomotive, electric vehicle, etc. Electric vehicles do not need to consume gasoline, let alone exhaust gas, and the noise is small.

The main shaft drive and feed transmission of CNC machine tools are all AC drive, which requires wide range of speed regulation and small static difference rate; Servo feed system requires high output torque, good dynamic response and high positioning accuracy. Asynchronous motor or synchronous motor is being used to replace DC motor.
 
In order to ensure the safe operation at high speed, the mine hoisting machinery requires excellent speed regulation performance and position control to obtain stable and safe braking operation, eliminate runaway phenomenon and improve reliability.

Lifting and loading and unloading machinery, such as port machinery, shall be suitable for the harsh environment with salt fog, dust and large temperature difference change in open air operation, and can be started and adjusted quickly frequently. The use conditions of atomic energy and chemical equipment are bad and require a large speed regulation range. The electrical equipment of building is used for air conditioning system, elevator transmission and water supply system. Textile, food machinery such as spinning winding machine, meat mixer, etc.