High-precision stepping electronic expansion valve control method and system

Abstract

The invention provides a high-precision stepping type electronic expansion valve control method and system, the method is applied to a main control module of a stepping type electronic expansion valve drive circuit, and the method comprises the steps that parameters of an electronic expansion valve are initialized; calculating the opening degree deviation according to the current opening degree and the target opening degree of the electronic expansion valve, and calculating the current time interval according to the current time and the last valve adjusting time; judging that the opening degree deviation is smaller than a set adjusting threshold value; further judging whether the current time interval is greater than or equal to a fine tuning period; calculating a first average opening degree and a second average opening degree; and respectively calculating the closeness degrees of the first average opening degree and the second average opening degree with the target opening degree, and adjusting the opening degree of the electronic expansion valve. The control precision of the electronic expansion valve can be improved on the premise that the cost of the driving circuit and the electronic expansion valve is not increased.

Description

technical field [0001] The invention relates to the field of intelligent interaction technology, in particular to a high-precision step-by-step electronic expansion valve control method. Background technique [0002] The step-type electronic expansion valve is a throttling element that controls the flow of refrigerant by controlling the forward and reverse rotation of the stepping motor and the opening angle of the valve. It is divided into two types: direct-acting electronic expansion valve and deceleration electronic expansion valve. . At present, the common control methods of stepping electronic expansion valves include four-phase and eight-step, four-phase and four-step, two-phase and four-step, etc. [0003] In the refrigeration system, the method of controlling the superheat of the evaporator is usually used to adjust the opening of the electronic expansion valve. The control algorithms include PID algorithm, genetic algorithm, neural network algorithm, etc. The cont...

AI Technical Summary

Problems solved by technology

Some stepping motor drive chips have micro-step function, such as ST's L6258 and TI's DRV8846, etc., by distributing the magnitude of the two-phase current, the rotor of the electronic expansion valve moves to the middle position of the two stator poles. The control accuracy is equivalent to 1 / 8 step, but the disadvantage is that the dedicated drive chip is not suitable for four-phase electronic expansion valves, and the cost of the drive chip is relatively high, occupying more resources of the main controller chip

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