Coordinated control method for ultra-supercritical thermal power units based on sliding mode predictive control

Abstract

The invention provides a coordinated control method of an ultra-supercritical thermal power unit based on sliding mode predictive control. The coordinated control method comprises the following steps:step one, establishing a boiler-turbine system nonlinear control model of the ultra super-critical unit and identifying model parameters in a receding manner according to historical running data of aunit distributed control system; step two, decoupling and linearizing the boiler-turbine system by adopting an input-output feedback linearization method; step three, by aiming at a quasi-linear model, constructing a predictive model of sliding mode functions and designing a discrete sliding mode control law; step four, considering the constraint conditions of the boiler-turbine system, establishing the receding horizon optimization problem and designing a dual-mode control law; step five, determining controller parameters to ensure the stability and dynamic performance of a closed-loop control system of a boiler-turbine. The coordinated control method of the ultra-supercritical thermal power unit based on the sliding mode predictive control, provided by the invention, has the advantagesthat the fast tracking performance and robustness of a unit coordination control system can be improved, and technical support is provided for the safe and economic operation of the thermal power unit.

Description

technical field [0001] The invention relates to a coordinated control method for ultra-supercritical thermal power units, in particular to a coordinated control method for units based on input-output feedback linearization, discrete sliding mode control and predictive control, and belongs to the technical field of thermal power control and optimization. Background technique [0002] Due to the advantages of high energy utilization efficiency and relatively low pollutant emission, ultra-supercritical coal-fired units have been valued by the power industry. In order to make full use of renewable energy, more and more ultra-supercritical units need to participate in grid peak regulation at the same time. Through technological progress, improving the quality of coordinated control can not only improve the load following performance and meet the peak shaving requirements, but also improve the economy and safety of unit operation, thereby prolonging the life of equipment and reduc...

AI Technical Summary

Problems solved by technology

However, this method is based on the linear model established by the local operating point, which cannot reflect the nonlinear characteristics of the full operating condition of the ultra-supercritical unit.

At present, most of the actual power plants adopt the traditional coordinated control method of cascade PID control + feedforward control, and its control performance is easily affected by external disturbances, reflected in the frequent fluctuations of the main steam pressure and the intermediate point temperature

Therefore, under the condition of large-scale variable load operation of ultra-supercritical units, the existing patented technology and conventional coordinated control methods cannot meet the requirements of rapidity, stability and robustness at the same time.

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