Advanced cascade control method and device

Abstract

The embodiment of the present application discloses an advanced cascade control method and device. A conventional integrator and a conventional differentiator in the prior art are improved. A sliding-window filter improves the conventional integrator and the conventional differentiator into a similar integrator and a sliding-window tracking differentiator respectively. Similar proportional integral control belongs to lag control while similar proportional differential control belongs to advanced control such that the advanced cascade control method of the embodiment of the present invention isformed. The advanced cascade control method has output speed greater than that of a conventional PID controller in a open-loop condition, which indicates that the advanced cascade control method canincrease the speed given by process output tracking in closed loop control and the closed-loop control loop formed by the advanced cascade control method has better control quality for difficult control process.

Description

technical field [0001] The invention relates to the technical field of thermal power plant process control, in particular to an advanced cascade control method and device. Background technique [0002] In the process control of thermal power plants, the large lag process is ubiquitous. The so-called large lag is an abbreviation for the high-order larger inertia and larger pure lag characteristics. It is generally believed that: in a large hysteresis process, when the pure hysteresis ratio is above 40%, the process is a difficult-to-control process. Difficult-to-control processes have always been one of the technical problems plaguing the process control of thermal power plants. [0003] In industrial control process, PID controller is the most widely used controller. Usually, an engineer needs to know the precise model of the controlled object when designing a PID controller, but in actual engineering, the precise model is often difficult to obtain. In the absence of a mo...

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Problems solved by technology

Usually, engineers need to know the precise model of the controlled object when designing a PID controller, but in actual engineering, the precise model is often difficult to obtain

In the absence of a model, designing and tuning PID control parameters is a complicated debugging process. If the on-site engineers and technicians do not understand the characteristics of the controlled object, inappropriate debugging methods may cause the system to diverge and cause accidents. The process is a time-consuming and laborious work, and it is not necessarily possible to obtain satisfactory control quality

There are two main problems in the existing PID controller, one is that the differential control is not efficient in tracking the differential, and the other is that the integral control is not efficient in tracking the steady-state deviation

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