Triple-tube heat recovery multi-connected air conditioning unit and control method thereof

Abstract

The present application belongs to the technical field of air conditioners, and specifically provides a three-pipe heat recovery multi-connected air conditioning unit and a control method thereof. The present application aims to solve the problem of excessive noise generated by the electronic expansion valve of the indoor unit of the existing three-pipe heat recovery multi-connected air conditioning unit and the control method thereof during the opening process. To this end, the three-pipe heat recovery multi-connected air conditioning unit of the present application comprises a plurality of indoor units arranged in parallel and a valve box connected to the indoor units, and the valve box is provided with an electronic expansion valve. The control method of the present application comprises: during the process of opening the electronic expansion valve from the closed state to the target opening degree, first controlling the electronic expansion valve to open to the preset opening degree in the form of intermittent increase in opening degree; and when the opening degree of the electronic expansion valve reaches the preset opening degree, controlling the electronic expansion valve to open in the form of continuous increase in opening degree, so as to divide the opening process of the electronic expansion valve into multiple stages, effectively reduce the impact of the refrigerant on the electronic expansion valve during the opening process, and achieve the effect of noise reduction.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of air conditioners, and specifically provides a three-pipe heat recovery multi-connected air conditioning unit and a control method thereof. BACKGROUND

[0002] With the continuous development of air conditioning technology, various types of air conditioning units are constantly being designed to adapt to different application scenarios; among them, the three-pipe heat recovery multi-connected air conditioning unit is very popular because it can simultaneously meet the different heat exchange needs of multiple indoor units, and the valve box, as an important control bridge of the three-pipe heat recovery multi-connected air conditioning unit, enables the unit to realize different heat exchange modes of refrigeration and heating of multiple indoor units at the same time through the action of the valve box, so as to meet the different heat exchange needs of users. When the indoor unit switches between the refrigeration and heating modes, the electronic expansion valve in the valve box needs to be switched between opening and closing to realize the conversion of the demand mode of the indoor unit. However, since the electronic expansion valve in the valve box will be impacted by the refrigerant during the process of switching from the closed state to the open state, and the diameter of the valve port is usually large (usually φ10mm-φ15mm), the noise generated is large. Generally, the electronic expansion valve in the existing valve box directly adopts the uniform speed regulation opening degree method to perform the opening and closing actions, and the noise generated during the mode switching process is large, resulting in poor user experience.

[0003] Accordingly, there is a need in the art for a new three-pipe heat recovery multi-connected air conditioning unit and a control method thereof to solve the above problems. SUMMARY

[0004] The present application aims to solve the above technical problems, i.e., to solve the problem of excessive noise generated by the electronic expansion valve of the indoor unit of the existing three-pipe heat recovery multi-connected air conditioning unit and its control method during opening.

[0005] In a first aspect, the present application provides a control method for a three-pipe heat recovery multi-connected air conditioning unit, the three-pipe heat recovery multi-connected air conditioning unit comprising a plurality of indoor units arranged in parallel and a valve box connected to the indoor units, the valve box being provided with an electronic expansion valve,

[0006] The control method comprises:

[0007] During the process of opening the electronic expansion valve from the closed state to the target opening degree, the electronic expansion valve is first controlled to open to a preset opening degree in the form of intermittent increase in opening degree;

[0008] When the opening degree of the electronic expansion valve reaches the preset opening degree, the electronic expansion valve is further controlled to open in the form of continuous increase in opening degree.

[0009] In the preferred technical scheme of the control method for the three-pipe heat recovery multi-connected air conditioning unit, the determination manner of the preset opening degree is:

[0010] continuously opening the electronic expansion valve from the closed state to the target opening degree;

[0011] detecting the noise value generated by the electronic expansion valve multiple times during the opening process of the electronic expansion valve;

[0012] determining the maximum value of the noise value in the change process according to the noise values generated by the electronic expansion valve detected multiple times;

[0013] the opening degree of the electronic expansion valve corresponding to the maximum value of the noise value is the preset opening degree.

[0014] In the preferred technical scheme of the control method for the three-pipe heat recovery multi-connected air conditioning unit, the step of "detecting the noise value generated by the electronic expansion valve multiple times" specifically includes:

[0015] the noise value of the electronic expansion valve corresponding to the opening degree is detected every time the opening degree changes.

[0016] In the preferred technical scheme of the control method for the three-pipe heat recovery multi-connected air conditioning unit, the step of "determining the maximum value of the noise value in the change process according to the noise values generated by the electronic expansion valve detected multiple times" specifically includes:

[0017] a curve change graph of the noise value with respect to the opening degree is drawn according to the noise values generated by the electronic expansion valve detected multiple times;

[0018] the maximum value of the noise value in the change process is determined according to the drawn curve change graph.

[0019] In the preferred technical scheme of the control method for the three-pipe heat recovery multi-connected air conditioning unit, the step of "controlling the electronic expansion valve to open to the preset opening degree in the form of intermittent increase of the opening degree" specifically includes:

[0020] controlling the electronic expansion valve to open at a preset speed uniformly in the first preset time length in each second;

[0021] controlling the electronic expansion valve to stop opening in the remaining time length in each second;

[0022] the above steps are repeatedly executed until the electronic expansion valve opens to the preset opening degree.

[0023] In the preferred technical scheme of the control method for the three-pipe heat recovery multi-connected air conditioning unit, the preset speed is the excitation speed of the electronic expansion valve.

[0024] In the preferred embodiment of the control method for the above-mentioned three-pipe heat recovery multi-split air conditioning unit, when the preset opening degree includes a first preset opening degree and a second preset opening degree, the step of "controlling the electronic expansion valve to open to the preset opening degree in an intermittently increasing manner" specifically includes:

[0025] First, control the electronic expansion valve to open to the first preset opening degree by intermittently increasing the opening degree;

[0026] Then, the electronic expansion valve is controlled to open to the second preset opening degree in an intermittently increasing manner.

[0027] In the preferred technical solution of the control method for the above-mentioned three-pipe heat recovery multi-split air conditioning unit, the step of "firstly controlling the electronic expansion valve to open to the first preset opening degree in an intermittently increasing manner" specifically includes:

[0028] The electronic expansion valve is controlled to open at a predetermined speed within the first preset time period per second.

[0029] The electronic expansion valve is controlled to stop opening for the remaining time of each second.

[0030] Repeat the above steps until the electronic expansion valve opens to the first preset opening degree.

[0031] In the preferred embodiment of the control method for the above-mentioned three-pipe heat recovery multi-split air conditioning unit, the step of "re-controlling the electronic expansion valve to open to the second preset opening degree in an intermittently increasing manner" specifically includes:

[0032] The electronic expansion valve is controlled to open at a constant speed within the first second preset time period per second;

[0033] The electronic expansion valve is controlled to stop opening for the remaining time of each second.

[0034] Repeat the above steps until the electronic expansion valve opens to the second preset opening degree.

[0035] In a second aspect, the present invention also provides a three-tube heat recovery multi-split air conditioning unit, the three-tube heat recovery multi-split air conditioning unit including a controller, the controller being capable of executing the control method described in any of the above preferred technical solutions.

[0036] In the technical scheme, the three-pipe heat recovery multi-connected air conditioning unit comprises a plurality of indoor units arranged in parallel and a valve box connected with the indoor units, and an electronic expansion valve is arranged in the valve box. The control method comprises: in the process that the electronic expansion valve is opened from the closed state to the target opening degree, the electronic expansion valve is first controlled to be opened to a preset opening degree in the intermittent opening degree increasing mode; and when the opening degree of the electronic expansion valve reaches the preset opening degree, the electronic expansion valve is controlled to be opened in the continuous opening degree increasing mode. Based on the control method, the opening process of the electronic expansion valve is divided into a plurality of stages, so that the impact of the refrigerant on the electronic expansion valve in the opening process of the electronic expansion valve is effectively reduced, the noise reduction effect is effectively achieved, and the user experience is improved. BRIEF DESCRIPTION OF DRAWINGS

[0037] The preferred embodiments of the present application will be described below with reference to the accompanying drawings, in which:

[0038] Figure 1 is a schematic diagram of the overall structure of the three-pipe heat recovery multi-connected air conditioning unit of the present application;

[0039] Figure 2 is a main step flowchart of the control method of the present application;

[0040] Figure 3 is a graph of the relationship between the opening degree of the electronic expansion valve and time of the present application;

[0041] Figure 4 is a graph of the relationship between the opening degree of the electronic expansion valve and time in a specific example;

[0042] Reference signs:

[0043] 11, compressor; 12, outdoor heat exchanger; 13, throttling member; 14, indoor heat exchanger; 15, valve box. DETAILED DESCRIPTION

[0044] The preferred embodiments of the present application will be described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present application, and are not intended to limit the protection scope of the present application. Those skilled in the art can make adjustments as needed to adapt to specific application occasions. For example, although the three-pipe heat recovery multi-connected air conditioning unit described in the preferred embodiments comprises three indoor units, this is not a limitation, and those skilled in the art can obviously set the specific number of indoor units according to actual use requirements. Such changes related to the specific number of indoor units do not deviate from the basic principles of the present application and are within the protection scope of the present application.

[0045] It should be noted that in the description of the preferred embodiment, the terms indicating the direction or positional relationship of the terms "in", "out" and the like are based on the direction or positional relationship shown in the drawings, which is only for the convenience of description, and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, in the description of the present application, unless otherwise explicitly specified and limited, the term "connected" and the like should be broadly understood, for example, it can be directly connected, or indirectly connected through an intermediate medium, or the internal communication of two elements. In addition, the terms "first", "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance.

[0046] In addition, it should also be noted that for those skilled in the art, the specific meaning of the above-mentioned terms in the present application can be understood according to the specific circumstances. Although the steps of the control method of the present application are described in a specific order in the present application, these orders are not limiting, and those skilled in the art can perform the steps in different orders without deviating from the basic principles of the present application.

[0047] First refer to Figure 1 , which is a schematic diagram of the overall structure of the three-tube heat recovery multi-connected air conditioning unit of the present application. As Figure 1 shown, the three-tube heat recovery multi-connected air conditioning unit of the present application includes an indoor unit part and an outdoor unit part, a refrigerant circulation circuit is provided between the indoor unit part and the outdoor unit part, the refrigerant circulation circuit circulates a refrigerant used for heat exchange between the indoor and outdoor, and the refrigerant circulation circuit is provided with a compressor 11, an outdoor heat exchanger 12, a throttling member 13, an indoor heat exchanger 14 and a valve box 15 (the part shown in the dashed line box); wherein the compressor 11 and the outdoor heat exchanger 12 are provided in the outdoor unit part, the specific position of the throttling member 13 is not limited, as long as the throttling member 13 can play a whole throttling role on the refrigerant circulation circuit, in the preferred embodiment, the indoor unit part includes three indoor units, the indoor heat exchanger 14 and the valve box 15 are provided in the corresponding indoor unit, it can be understood that one indoor unit can be provided with only one indoor heat exchanger 14 and one valve box 15, or multiple indoor heat exchangers 14 and multiple valve boxes 15, as long as the indoor heat exchanger 14 and the valve box 15 are correspondingly provided. The refrigerant circulates between the outdoor heat exchanger 12 and the multiple indoor heat exchangers 14 through the refrigerant circulation circuit to achieve heat exchange, two electronic expansion valves are correspondingly provided in each valve box 15, and the heat exchange state of the corresponding indoor heat exchanger 14 can be controlled by controlling the opening and closing state of the electronic expansion valve.

[0048] It should be noted that the present application does not make any limitation on the specific structure and composition of the three-tube heat recovery multi-connected air conditioning unit, and those skilled in the art can set it according to the actual use requirements, as long as the three-tube heat recovery multi-connected air conditioning unit comprises the corresponding indoor heat exchanger 14 and valve box 15, and the specific type and specific number of indoor heat exchanger 14 and valve box 15 are not limited.

[0049] Further, the three-tube heat recovery multi-connected air conditioning unit further comprises a controller, which can obtain the operating parameters of the three-tube heat recovery multi-connected air conditioning unit and control the operating state of the three-tube heat recovery multi-connected air conditioning unit, for example, control the opening and closing state of the electronic expansion valve. Those skilled in the art can understand that the present application does not make any limitation on the specific structure and model of the controller, and the controller can be the original controller of the three-tube heat recovery multi-connected air conditioning unit, or a controller specially set for the control method of the present application. Those skilled in the art can set the structure and model of the controller according to the actual use requirements.

[0050] Next, refer to Figure 2 , which is the main step flow chart of the control method of the present application. As Figure 2 shown, based on the three-tube heat recovery multi-connected air conditioning unit described in the above embodiment, the control method of the present application mainly comprises the following steps:

[0051] S1: In the process of opening the electronic expansion valve from the closed state to the target opening degree, first control the electronic expansion valve to open to the preset opening degree in the way of intermittent increase of opening degree;

[0052] S2: When the opening degree of the electronic expansion valve reaches the preset opening degree, control the electronic expansion valve to open in the way of continuous increase of opening degree.

[0053] In step S1, in the process of opening the electronic expansion valve from the closed state to the target opening degree, of course, the electronic expansion valve can be Figure 1Any electronic expansion valve in the valve box 15, as long as it is an electronic expansion valve in the valve box 15, and the present application does not make any restrictions on the specific value of the target opening degree, and the person skilled in the art can set it according to the actual use requirement, which is not restrictive; during the opening process of the electronic expansion valve, the controller first controls the electronic expansion valve to open to the preset opening degree in the way of intermittent increase of the opening degree, and it should be noted that the way of intermittent increase of the opening degree here is to first increase the opening degree of the electronic expansion valve at a constant speed for a certain period of time, then stop increasing the opening degree of the electronic expansion valve for a certain period of time, and repeat this control mode, and of course, it should be noted that the time length of uniform speed regulation of the opening degree and the time length of stop increasing the opening degree are not restrictive, and the person skilled in the art can set them according to the actual use requirement. In addition, the present application does not make any restrictions on the specific value of the preset opening degree, and the person skilled in the art can set it according to the actual use requirement.

[0054] In step S2, when the opening degree of the electronic expansion valve reaches the preset opening degree, the electronic expansion valve is controlled to open in the way of continuous increase of the opening degree. Specifically, after the opening degree of the electronic expansion valve is increased from the closed state to the preset opening degree in the control mode in step S1, the electronic expansion valve is controlled to open in the way of continuous increase of the opening degree, that is, the electronic expansion valve is controlled to continuously increase its opening degree at a constant speed. It should be noted that the present application does not make any restrictions on the specific value of the preset opening degree and the opening speed of the electronic expansion valve, and the person skilled in the art can set them according to the actual use requirement, which is not restrictive.

[0055] Based on the above control mode, the present application effectively reduces the impact of the refrigerant on the electronic expansion valve during the opening process of the electronic expansion valve by dividing the opening process of the electronic expansion valve into multiple stages, thereby effectively achieving the effect of reducing noise and improving user experience.

[0056] As a preferred implementation, the preset opening degree is determined by: continuously opening the electronic expansion valve from the closed state to the target opening degree; detecting the noise value generated by the electronic expansion valve multiple times during the opening process of the electronic expansion valve; determining the maximum value of the noise value in the variation process according to the multiple detected noise values generated by the electronic expansion valve; and determining the opening degree of the electronic expansion valve corresponding to the maximum value of the noise value as the preset opening degree. It should be noted that the above determination method is preferably tested before the three-pipe heat recovery multi-split air conditioning unit is shipped, and the test results are stored in the controller, so that the controller can control the three-pipe heat recovery multi-split air conditioning unit after it is shipped. In addition, the present application does not limit the detection method of the noise value generated by the electronic expansion valve, and preferably directly measures by setting a noise measuring device near the electronic expansion valve.

[0057] Further, in the process of determining the preset opening degree, as a preferred method, the step of "detecting the noise value generated by the electronic expansion valve multiple times" specifically includes: detecting the noise value of the electronic expansion valve corresponding to the opening degree each time the opening degree of the electronic expansion valve changes. It can be understood that the opening degree of the electronic expansion valve usually needs to be adjusted step by step, that is, the noise value corresponding to the opening degree is detected each time the opening degree of the electronic expansion valve is adjusted, so as to effectively improve the accuracy of control, thereby maximizing the noise reduction effect of the present application.

[0058] Further, as a preferred determination method of the maximum value, the step of "determining the maximum value of the noise value in the variation process according to the multiple detected noise values generated by the electronic expansion valve" specifically includes: drawing a curve change graph of the noise value with respect to the opening degree according to the multiple detected noise values generated by the electronic expansion valve; and determining the maximum value of the noise value in the variation process according to the drawn curve change graph. Determining the maximum value of the noise value based on the curve drawing method can maximize the accuracy of the results, thereby effectively improving the accuracy of the control effect.

[0059] In addition, as a preferred control mode, the electronic expansion valve is controlled in the following intermittent opening degree increasing mode: the electronic expansion valve is controlled to be opened at a preset speed for a preset time length in each second; the electronic expansion valve is controlled to stop opening for the remaining time length in each second; the above steps are cyclically executed until the electronic expansion valve is opened to the preset opening degree. It should be noted that the present application does not limit the specific proportion of the time length for opening degree adjustment and the time length without opening degree adjustment of the electronic expansion valve in each second, and as a preferred setting mode, the time length used in the process of adjusting the electronic expansion valve to the preset opening degree is determined by detecting the noise value, and the noise generated is the smallest when the time length is determined, and then the specific proportion of the time length for opening degree adjustment and the time length without opening degree adjustment in each second is determined in order to further improve the noise reduction effect.

[0060] Based on the control mode described in the preferred embodiment, as a preferred example, the number of preset opening degrees is one, that is, in the case that there is only one maximum value of the noise value generated by the electronic expansion valve in the opening degree adjustment process of the electronic expansion valve, the entire opening process of the electronic expansion valve is divided into two control stages. Specifically, as shown in FIG. 4, the opening process of the electronic expansion valve is divided into two control stages, that is, the first control stage and the second control stage. Figure 3As shown, assuming that the maximum opening degree of the electronic expansion valve is B, and the target opening degree is set to the maximum opening degree B, according to the noise test, it is determined that the flow of the electronic expansion valve starts to increase sharply at the opening degree A, and the noise is also the largest, as the maximum value of the noise value, so the opening degree A is a demarcation point. The opening process of the electronic expansion valve is divided into two parts from 0 pls to A pls and from A pls to B pls according to the opening degree change process thereof, and the control focus of the present application is how to reduce the noise of the adjustment process from 0 pls to A pls. Assuming that the excitation speed of the electronic expansion valve is v pls / s, according to the noise test, it is determined that the noise generated when the electronic expansion valve opens a certain number of steps per second is reduced to a minimum, that is, if it is determined that the noise generated when the opening degree of the electronic expansion valve changes from 0 pls to A pls through the t1 time is the smallest, then the number of steps required for adjustment of the electronic expansion valve per second is A / t1 pls, and according to the excitation speed of the electronic expansion valve, the time length required for the electronic expansion valve to open at a constant speed per second is A / t1 / v seconds, and the time length of the electronic expansion valve maintaining the current opening degree per second is 1-A / t1 / v seconds, finally making the electronic expansion valve increase the opening degree in an intermittent manner and increasing the opening degree to the preset opening degree (i.e. A opening degree) after t1 time length; and in the adjustment process of the opening degree of the electronic expansion valve from A pls to B pls, the flow change is not so large, and accordingly the noise generated is not very large, in order to effectively ensure the opening speed of the electronic expansion valve, in this adjustment process, the electronic expansion valve can be controlled to open at a constant speed at the excitation speed, so that the electronic expansion valve opens at a constant speed at the excitation speed for t2 time length, and then the opening degree is increased to the target opening degree (i.e. the maximum opening degree B), thereby maximizing the noise reduction effect.

[0061] Further, as a specific example, as Figure 4As shown, taking the target opening degree 600 pls of the electronic expansion valve, the excitation speed 31.5 pls / s, and the maximum value of the noise value 100 pls as examples, if it is determined through the noise test that the noise generated by the electronic expansion valve is the lowest when the opening degree of the electronic expansion valve is increased to 100 pls in 50 s, that is, the electronic expansion valve needs to be opened by 2 pls per second, and according to the excitation speed 31.5 pls / s of the electronic expansion valve, it is determined that the opening degree of the electronic expansion valve needs to be increased by 2 pls for only 63 ms, based on which, during the adjustment process of the electronic expansion valve in the first 50 s, the opening degree of the electronic expansion valve is intermittently increased in a manner that the excitation speed is increased by 63 ms per second and the remaining 937 ms are stopped for adjustment, until the opening degree of the electronic expansion valve reaches 100 pls after being adjusted in this manner for 50 s. After the opening degree of the electronic expansion valve reaches 100 pls, during the process of adjusting the opening degree of the electronic expansion valve from 100 pls to 600 pls, the electronic expansion valve is always continuously opened at the excitation speed, that is, the opening degree thereof is always increased at the speed of 31.5 pls / s, and reaches the target opening degree after 16 s.

[0062] In addition, it also needs to be noted that when the value of the target opening degree is large, there can be multiple preset opening degrees determined through the noise test, and taking the case where the preset opening degrees include a first preset opening degree and a second preset opening degree as an example, the step of “controlling the electronic expansion valve to be opened to a preset opening degree in an intermittent opening degree increasing manner” specifically includes: first controlling the electronic expansion valve to be opened to the first preset opening degree in an intermittent opening degree increasing manner; and then controlling the electronic expansion valve to be opened to the second preset opening degree in an intermittent opening degree increasing manner. Based on this control manner, the opening process of the electronic expansion valve can be divided into three stages, the first two stages are opened in an intermittent opening degree increasing manner, and the third stage is opened in a continuous opening degree increasing manner, so as to minimize the noise while effectively ensuring the opening speed,

[0063] Specifically, the step of “first controlling the electronic expansion valve to be opened to the first preset opening degree in an intermittent opening degree increasing manner” specifically includes: controlling the electronic expansion valve to be uniformly opened at a preset speed for a first preset time length per second; controlling the electronic expansion valve to be stopped for opening for the remaining time length per second; and cyclically executing the above steps until the electronic expansion valve is opened to the first preset opening degree. It needs to be noted that as a preferred setting manner, the value of the first preset time length is determined in the manner described in the previous embodiment, which will not be described here again.

[0064] In addition, the step of "controlling the electronic expansion valve to open to the second preset opening degree in a manner of intermittently increasing the opening degree" specifically comprises: controlling the electronic expansion valve to open at a preset speed for a second preset time length in each second; controlling the electronic expansion valve to stop opening for the remaining time length in each second; and cyclically executing the above steps until the electronic expansion valve opens to the second preset opening degree. It should be noted that, as a preferred setting manner, the value of the second preset time length is determined in the manner described in the previous embodiment, and thus will not be described here.

[0065] In addition, it should be further noted that the present application does not make any limitation on the number of stages in the adjustment process of the electronic expansion valve, and a person skilled in the art can set it according to the actual use requirements, as long as the electronic expansion valve includes the two adjustment stages of intermittently increasing the opening degree and continuously increasing the opening degree in the process of opening from the closed state to the target opening degree, which belongs to the protection scope of the present application.

[0066] So far, the technical solutions of the present application have been described in combination with the preferred embodiments shown in the drawings, but a person skilled in the art can easily understand that the protection scope of the present application is obviously not limited to these specific embodiments. A person skilled in the art can make equivalent changes or replacements to the related technical features without departing from the principles of the present application, and the technical solutions after the changes or replacements will all fall within the protection scope of the present application.

Claims

1. A control method for a three-pipe heat recovery multi-connected air conditioning unit, the three-pipe heat recovery multi-connected air conditioning unit comprising a plurality of indoor units arranged in parallel and a valve box connected to the indoor units, the valve box being provided with an electronic expansion valve, characterized in that The control method comprises: During the process that the electronic expansion valve is opened from the closed state to the target opening degree, the electronic expansion valve is first controlled to be opened to a preset opening degree in the form of intermittent increase in opening degree; When the opening degree of the electronic expansion valve reaches the preset opening degree, the electronic expansion valve is further controlled to be opened in the form of continuous increase in opening degree.

2. The control method according to claim 1, characterized by, The determination method of the preset opening degree is: The electronic expansion valve is continuously opened from the closed state to the target opening degree; During the opening process of the electronic expansion valve, the noise value generated by the electronic expansion valve is detected multiple times; According to the noise values generated by the electronic expansion valve detected multiple times, the maximum value of the noise value in the change process is determined; The opening degree of the electronic expansion valve corresponding to the maximum value of the noise value is determined as the preset opening degree.

3. The control method according to claim 2, characterized by, The step of "detecting the noise value generated by the electronic expansion valve multiple times" specifically comprises: Each time the opening degree of the electronic expansion valve changes, the noise value of the electronic expansion valve corresponding to the opening degree is detected.

4. The control method according to claim 2, characterized by, The step of "determining the maximum value of the noise value in the change process according to the noise values generated by the electronic expansion valve detected multiple times" specifically comprises: According to the noise values generated by the electronic expansion valve detected multiple times, a curve change graph of the noise value with respect to the opening degree is drawn; According to the drawn curve change graph, the maximum value of the noise value in the change process is determined.

5. The control method according to any one of claims 1 to 4, characterized by, The step of "controlling the electronic expansion valve to be opened to a preset opening degree in the form of intermittent increase in opening degree" specifically comprises: The electronic expansion valve is controlled to be opened at a preset speed uniformly in the first preset time length in each second; The electronic expansion valve is controlled to stop opening in the remaining time length in each second; The above steps are repeatedly executed until the electronic expansion valve is opened to the preset opening degree.

6. The control method according to claim 5, characterized by The preset speed is the excitation speed of the electronic expansion valve.

7. The control method according to any one of claims 1 to 4, characterized by, In the case where the preset opening degree comprises a first preset opening degree and a second preset opening degree, the step of "controlling the electronic expansion valve to be opened to a preset opening degree in the form of intermittent increase in opening degree" specifically comprises: The electronic expansion valve is first controlled to be opened to the first preset opening degree in the form of intermittent increase in opening degree; The electronic expansion valve is further controlled to be opened to the second preset opening degree in the form of intermittent increase in opening degree.

8. The control method according to claim 7, characterized by, The step of "first controlling the electronic expansion valve to be opened to the first preset opening degree in the form of intermittent increase in opening degree" specifically comprises: The electronic expansion valve is controlled to be opened at a preset speed uniformly in the first preset time length in each second; The electronic expansion valve is controlled to stop opening in the remaining time length in each second; The above steps are repeatedly executed until the electronic expansion valve is opened to the first preset opening degree.

9. The control method according to claim 7, characterized by, The step of "further controlling the electronic expansion valve to be opened to the second preset opening degree in the form of intermittent increase in opening degree" specifically comprises: The electronic expansion valve is controlled to be opened at a preset speed uniformly in the second preset time length in each second; controlling the electronic expansion valve to stop opening for the remaining time length in each second; the above steps are executed in a cycle until the electronic expansion valve is opened to the second preset opening degree.

10. A triple-pipe heat recovery multi-connected air conditioning unit, characterized in that, The three-pipe heat recovery multi-connected air conditioning unit comprises a controller, and the controller can execute the control method in any one of claims 1 to 9.

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