Automatic air supply control system of boiler

The utility model relates to an automatic air supply control system of a boiler, which is used for air volume control of an air supply machine group. The automatic air supply control system comprises a load control loop, a filtering processing module, a preset air volume module and a general selection processing module, wherein the load control loop comprises a function calculation module; the function calculation module is used for receiving a power instruction after speed limitation and outputting a first air volume value; the filtering processing module is connected with the function calculation module and is used for outputting a second air volume value; the preset air volume module is used for outputting a third air volume value according to present purging air volume or minimum air volume; and the general selection processing module is connected with output of the function calculation module, the filtering processing module and the preset air volume module respectively and is used for selecting maximum value according to the received first air volume value, the second air volume value and the third air volume to generate an air supply instruction. By the automatic air supply control system of the boiler, provided by the technical scheme of the utility model, the total air volume can be controlled within a reasonable range all the time and changes with the load, and meanwhile, oxygen content in a hearth also is kept within a controlled range all the time.