PID control method of applying variation trend of controlled variable

Abstract

The present invention relates to a PID control method of applying variation trend of a controlled variable. The method selects the appropriate positive and negative deviation values according to the variation rate of the controlled variable, when the controlled variable varies between a set value and a negative deviation value and is located during a rising process or the controlled variable varies between the set value and a positive deviation value and is located during a falling process, the valve location of an adjusting valve does not vary, and the adjusting valve adjusts according to a conventional PID control technology at other time. By utilizing the method of the present invention to adjust and control the controlled variable, the overshoot times and the amplitude can be reduced, the lag time is shortened, a tracking effect of the controlled variable is improved obviously, and the control precision and the gentle degree can be improved by more than 50%, at the same time, the frequent action time of an execution mechanism, for example, the adjusting valve is also reduced, and the usage time of a device is prolonged.

Description

technical field [0001] The invention relates to the technical field of PID control, in particular to a PID control method using the variation trend of a controlled quantity. Background technique [0002] In the actual control system, when using conventional PID control technology to adjust the controlled quantity, problems such as overshoot, large fluctuation and lag often occur, the controlled quantity cannot track the set value in time and accurately, and the control effect is difficult to reach the user. demand. [0003] The adjustment process of the traditional PID control method is as follows: figure 1 As shown, in section A→B, section E→F, and section I→J, the actual value of the controlled quantity is less than the set value, and the output control quantity of the controller increases. If the actuator adopts a regulating valve, the increase of the control amount output by the controller corresponds to the increase of the opening of the regulating valve. For example...

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Problems solved by technology

[0005] The purpose of the present invention is to address the deficiencies of the prior art, to provide a PID control method using the changing trend of the controlled quantity, which can solve the problems of overshoot, large oscillation, and hysteresis of the PID control, so that the controlled quantity can be timely and timely Accurately track setpoints

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