Application Of Predictive Control Algorithm In PLC

Programmable logic controller(PLC)as an important control algorithm implementation platform has the characteristics of low cost,stable operation and high reliability,and occupies an important position in the industrial process.In recent years,the advanced control technology represented by predictive control has greatly improved the automation level of industrial production and has received widespread attention in the industry and academia.However,traditional predictive control algorithms are more complex and difficult to apply to PLC with limited computing resources which limits the further promotion of predictive control technology.Therefore,simplifying the predictive control algorithm and improving the optimization problem solving ability have an important role in implementing the predictive control technology on the PLC This article takes PLC as the platform and expounds the application practice of the predictive control algorithm carried out on it.The main work contents are as follows1.The basic principle of predictive function control is reviewed and elaborated,and the optimal controller for denitration of a thermal power plant is designed on the PLC.By controlling the amount of ammonia sprayed in the denitrification link,the concentration of nitrogen oxides at the outlet of the catalyst can track the set value quickly,and respond to ground disturbances in various situations,improving the level of automatic control in the denitrification link.2.A fast algorithm for multivariable predictive control based on GPAD is proposed.Use the multivariable model to predict the future output of the model recursively;form a QP problem based on quadratic optimization indicators;introduce the GPAD optimization algorithm to speed up the solution of QP problems.Numerical experiment results show that this method has faster calculation speed and better control effect than conventional algorithms3.A fast algorithm of multi-variable predictive control based on GPAD is implemented on the PLC and applied to the two-input and two-output tank level control system.The experimental results confirm the efficiency of the algorithm,and can deal with input and output constraints systematically.It has excellent performance in both fast and slow processes,and the algorithm has a wide range of application prospects.