Double-circuit control method for variable air volume air conditioning water chilling unit

Abstract

The invention discloses a double-circuit control method for a variable air volume air conditioning water chilling unit. The method comprises the following steps that when the variable air volume air conditioning water chilling unit runs, a chilled water output and return temperature difference is set; when the measured value of the temperature difference does not conform to the set value, the set value of refrigerant flow at this moment is calculated; a main controller and an auxiliary controller are arranged in a control circuit, the frequency of a controlled object compressor is controlled through the deviation signal of the refrigerant flow, and finally accurate control over the chilled water temperature difference is achieved. A common PID and a fuzzy self-adaption PID are combined, the corresponding nonlinear problem can be solved, and the control effect can be achieved fast. A controlled object is recognized through a least square method, a fuzzy rule list of a fuzzy self-adaption PID controller is provided, parameters of the controllers are set in a simulation experiment, and the water chilling unit can run stably.

Description

technical field [0001] The invention relates to a double-loop control method for a variable air volume air conditioning chiller, and belongs to the technical field of variable air volume air conditioning. Background technique [0002] With the popularity of variable air volume air conditioning systems in recent years, many scholars have conducted in-depth research on the control and energy saving of variable air volume air conditioning. Such as figure 1 As shown, according to the existing knowledge, the variable air volume air conditioning system can be roughly divided into four parts: air circulation, water circulation, chiller, and control system. Eliminate heat and humidity loads in the room to meet people's daily needs; the main function of the water cycle is to serve as a medium for energy transfer in various links in the air-conditioning system, including chilled water loops, cooling water loops, etc.; chillers are responsible for generating cooling capacity, and It ...

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Problems solved by technology

[0013] like figure 2 As shown, the standard chiller control loop usually directly controls the frequency of the compressor when controlling the temperature difference between the chilled water outlet and return water. Since the control loop has the characteristics of nonlinearity and large time lag, it may cause fluctuations in the system and instability, poor control

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