1. Vehicle traction system. The operation of subway vehicles requires electric motors as driving force, and the control of traction motors requires frequency converters to adjust the motor speed to meet the speed requirements of rail transit vehicles.

 2. Air conditioning and ventilation system. The fan of the subway ventilation system uses a frequency converter to control the motor speed to adjust the air volume and wind pressure, and the air volume, intensity and temperature are adjusted in conjunction with the air quality inside and outside the vehicle compartment.

 3. Drainage pump station. The water level of the pool in the drainage pump room of the subway tunnel system needs to be controlled, and the adjustment of the water pump also requires the use of a frequency converter. Its main function is to automatically control the operation of the water pump according to different water levels.