Active disturbance rejection feedforward control method of lithium bromide absorption refrigerator

Abstract

The invention discloses an active disturbance rejection feedforward control method of a lithium bromide absorption refrigerator. According to the method, an object transfer function of the absorptionrefrigerator and a disturbance transfer function from a heat source water inlet temperature, a cooling water inlet temperature and a refrigerant water inlet temperature are obtained through open-loopstep identification; according to the control method, the refrigerant water outlet temperature serves as a controlled variable, the heat source water flow serves as a controlled variable, an auto-disturbance rejection control algorithm is designed, and auto-disturbance rejection control parameters are set through a provided quantitative parameter setting formula; the output of all feed-forward transfer functions is subtracted from the active disturbance rejection control output part, the feed-forward transfer functions are obtained by dividing disturbance transfer functions by object transferfunctions, and the feed-forward transfer functions can be simplified into zero-frequency gain. According to the invention, the implementation complexity of the control method is effectively reduced, and the workload of parameter setting is reduced; meanwhile, various measurable disturbances and unknown disturbances are restrained, the disturbance restraining speed of the refrigerant water outlet temperature is increased, and the fluctuation range of the refrigerant water outlet temperature is reduced.

Description

technical field [0001] The invention belongs to the field of automatic control of lithium bromide absorption refrigerators, in particular to an self-disturbance rejection feedforward control method of lithium bromide absorption refrigerators. Background technique [0002] Compared with the mechanical compression refrigerator, the absorption refrigerator has the characteristics of environmental protection, energy saving and low maintenance cost. Lithium bromide-water is a commonly used working fluid pair in absorption refrigerators. Because the refrigerant is water, it is harmless to the environment and the ozone layer of the atmosphere. Lithium bromide absorption chillers can utilize a variety of low-grade heat energy, such as waste heat, waste heat, solar heat, etc., so the energy-saving effect is good. In addition, absorption chillers have no moving parts other than pumps and valves, resulting in stable operation and simple, low-cost maintenance. [0003] Due to the abo...

AI Technical Summary

Problems solved by technology

The existing proportional-integral-derivative control is based on the method of setting value-feedback value error. The influence of the disturbance takes a long time to be reflected in the feedback value of the refrigerant water outlet temperature. The proportional-integral-derivative method is aimed at the suppression of disturbance The control action is lagging, so the speed of suppressing disturbances is still slow

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