Predictive Control Method Of Load Control In Ultra-supercritical Unit

Due to the characteristics of resources reserves in China, thermal powergeneration is the main way in the electric power industry, recently unit plant is widelyused in the thermal power generation. The task of unit plant load control system is tomake the output power can quickly response to load requirements of external powergrid, at the same time to guarantee the stability of the unit’s internal main steampressure.Unit plant is a typical multivariable controlled object in the field of control, atthe same time, that is a strong nonlinear and tight coupling complex controlled object.The dynamic characteristics of unit’s internal boiler and turbine are very different.With the progress of science and technology, the development of social productivity,the capacity of thermal power units will be larger, the required control ability will bestronger. The ultra-supercritical unit is the future development direction of thermalpower industry. All of these factors make the traditional control method which basedon the accurate mathematical model can’t achieve good control effect.Against this background, the theory research of unit load control becomes veryurgent.Model predictive control is appeared in the field of industrial process as anintelligent control method in the1970s. One of which is called the dynamic matrixcontrol(DMC), the selection for model is not strict. It only requires the model’sprediction, not its structure form. It’s very suitable for control of the complexcontrolled object. So researchers can establish load control object of multivariableDMC control system to achieve the simulation research.Firstly the dynamic characteristics of unit load control object are analyzed, andthe linear model of load control object is established. Then the principles and basicsolutions of unit load control are analyzed.The article analyzes the principle of predictive control algorithm, and completesthe mathematical derivation. Using the dynamic matrix control algorithm to achievethe research of the load control object, achieve the dynamic matrix control of load control. On the basis of the results, the Graphical User Interfaces was established. It’sconvenient for the user to view the control effect of the dynamic matrix control ofload control.By analyzing the performance index function in the multivariable DMCalgorithm, it is improved. Based on the theory, the article proposes a new kind ofcontrol algorithm, which is called “divide into multiple regions then select the bestresult”. Based on the control algorithm, a new kind of controller for achieving thesimulation research of load control has been established. Comparing the simulationresults with the DMC algorithm, the results show that the new control algorithm issuperior to the DMC algorithm.