Boiler denitration ammonia injection amount control method and system based on multi-factor compensation

The invention provides a boiler denitration ammonia injection amount control method and system based on multi-factor compensation, and relates to the technical field of thermal power plant coal-fired boiler flue gas denitration, and the method comprises the steps: generating a multi-factor comprehensive compensation value in real time according to load change, hearth oxygen amount deviation and SCR inlet NOx content change; using the multi-factor comprehensive compensation value to compensate an ammonia injection amount generation value of the typical denitration control method, and inputting the compensation value to an ammonia injection control valve PID controller in a typical denitration control loop to obtain an ammonia injection control valve opening degree; the multi-factor comprehensive compensation value is converted into the opening degree variable quantity of the ammonia injection control valve; based on the ammonia injection control valve opening degree and the opening degree variable quantity, th