Multi-model adaptive control method for denitration control system

Abstract

The invention relates to a multi-model adaptive control method for a denitration control system. The method comprises steps that 1, sub models of a controlled object under different loads are established; 2, PID controllers are respectively designed according to the m sub models; output of the controlled object and output of each sub model are acquired through measurement; 4, deviation of output of the controlled object and output of each sub model is acquired; 5, a weight wi of each controller is solved; 6, control quantities u1(k) to um(k) of the controllers are weighted to output to acquire a global control quantity up(k); 7, the global control quantity is sent to the controlled object and the sub models for control; and 8, the process returns to the step 3. The method is advantaged in that a global controller can be made to output the optimal control quantity in real time under the changeable load condition, the purpose of adaptive load change is realized, change of an export NOx concentration can be timely tracked according to change of ammonia injection amount, export NOx concentration fluctuation of the denitration system can be effectively reduced, so the NOx concentration is stabilized to be in an index required by the environmental protection department, control thinking is simple, and the method is easy for realization in a power plant DCS.

Description

technical field [0001] The invention belongs to the field of denitrification control, and in particular relates to a multi-model self-adaptive control method for a denitrification control system. Background technique [0002] At present, thermal power plants generally use a cascade control system to control the concentration of nitrogen oxides (NOx) at the outlet of the SCR denitrification system. The outlet NOx concentration is the main adjustment parameter, and the ammonia flow rate is the auxiliary adjustment parameter. Both the main and auxiliary regulators use a single PID control. . Through the adjustment of the secondary loop, the injection volume can quickly track the output of the main regulator, and through the adjustment of the main loop, the outlet NOx concentration can track the set value of the outlet NOx concentration. [0003] Thermal power plants adopt cascade control system to control the NOx concentration at the outlet of SCR denitrification system. The m...

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Problems solved by technology

However, both the main PID and the secondary PID of this invention need to be corrected, which is more complicated

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