An electronic expansion valve control method and control device, and a multi-split air conditioning system.

Abstract

This application provides an electronic expansion valve control method and control device, and a multi-split air conditioning system. It relates to the field of air conditioning vibration reduction and noise reduction technology, and is used to adjust the system's subcooling and the opening of the electronic expansion valve to change the flow pattern of refrigerant through the electronic expansion valve, reducing the proportion of gaseous refrigerant, thereby reducing refrigerant flow noise and improving the user experience. The control method includes: reading a temperature difference value, which is the difference between the temperature of the intermediate two-phase section of the indoor unit's heat exchanger and the outlet temperature; determining the subcooling of the electronic expansion valve based on the temperature difference value; calculating the subcooling difference value, which is the difference between the subcooling and the subcooling setpoint; determining the target opening of the electronic expansion valve based on the subcooling difference value; and adjusting the electronic expansion valve opening to the target opening to reduce the proportion of gaseous refrigerant and reduce refrigerant noise generated by the gaseous refrigerant.

Description

Technical Field

[0001] This application relates to the field of air conditioning vibration reduction and noise reduction, and in particular to an electronic expansion valve control method and control device, and a multi-split air conditioning system. Background Technology

[0002] As living standards improve, multi-split air conditioning systems have gradually entered thousands of households. Besides demanding good cooling and heating performance, users are also concerned about the comfort of using these systems. Noise reduction is an important aspect of enhancing the comfort of multi-split air conditioning systems.

[0003] A multi-split air conditioning system consists of an outdoor unit and multiple indoor units. Both the outdoor unit and the indoor units are equipped with electronic expansion valves to regulate the flow of refrigerant in the piping. Because the electronic expansion valve is a throttling device, when the refrigerant flows through it, the cross-sectional area through which the refrigerant passes decreases, causing a change in the fluid state of the refrigerant and thus generating noise. This noise generated by the refrigerant can be referred to as refrigerant flow noise or refrigerant sound.

[0004] How to reduce the refrigerant flow noise or refrigerant noise in multi-split air conditioning systems has become an urgent technical problem to be solved. Summary of the Invention

[0005] This application provides an electronic expansion valve control method and control device, as well as a multi-split air conditioning system. It aims to reduce the refrigerant flow noise generated when refrigerant flows through the electronic expansion valve, thereby improving the user experience, while maintaining the existing hardware resources of the multi-split air conditioning system.

[0006] To achieve the above objectives, the embodiments of this application adopt the following technical solutions:

[0007] The first aspect of this application provides an electronic expansion valve control method, including:

[0008] Read the temperature difference value, which is the difference between the temperature of the two middle phases of the indoor unit heat exchanger and the outlet temperature;

[0009] The subcooling of the electronic expansion valve is determined based on the temperature difference.

[0010] Calculate the subcooling difference, which is the difference between the subcooling value and the subcooling set value;

[0011] Determine the target opening degree of the electronic expansion valve based on the subcooling difference;

[0012] Adjust the opening of the electronic expansion valve to the target opening to reduce the proportion of gaseous refrigerant.

[0013] In conjunction with the first implementation of the first aspect, the control method further includes, prior to the step of reading the temperature difference value: reading the status of the indoor unit; if the status of the indoor unit is running; the step of determining the target opening of the electronic expansion valve based on the subcooling difference includes: if the subcooling difference is greater than a first subcooling constant, then the target opening is greater than the current opening of the electronic expansion valve; if the subcooling difference is between the first subcooling constant and zero, then the target opening is equal to the current opening of the electronic expansion valve; if the subcooling difference is less than zero, then the target opening is less than the current opening of the electronic expansion valve.

[0014] In conjunction with the second implementation method of the first aspect, if the indoor unit is in a non-operating state, the step of determining the target opening degree of the electronic expansion valve based on the subcooling difference also includes: if the subcooling difference is less than or equal to the second subcooling constant, the target opening degree is less than the current opening degree of the electronic expansion valve; if the subcooling difference is greater than the subcooling constant, the target opening degree is equal to the current opening degree of the electronic expansion valve.

[0015] In conjunction with the third implementation method of the first aspect, it also includes: reading the temperature difference value at predetermined intervals.

[0016] In conjunction with the fourth implementation method of the first aspect, it also includes: the second subcooling constant is greater than the first subcooling constant.

[0017] In conjunction with the fifth implementation method of the first aspect, it also includes: in response to starting the multi-split air conditioning system, adjusting the opening of the electronic expansion valve to an initial value; the initial value is related to the capacity of the indoor unit and the status of the indoor unit.

[0018] In conjunction with the sixth implementation method of the first aspect, it also includes: responding to the compressor frequency adjustment command, reading the compressor operating frequency and the target frequency carried by the command; if the compressor operating frequency is less than the target frequency, first increasing the opening of the electronic expansion valve and then increasing the compressor frequency.

[0019] In conjunction with the seventh implementation method of the first aspect, it also includes: if the compressor operating frequency is greater than the target frequency, first reduce the compressor frequency and then reduce the opening of the electronic expansion valve.

[0020] The control method provided in this application can calculate the temperature difference between the temperature of the two intermediate phases of the indoor unit heat exchanger and the outlet temperature; then, determine the subcooling degree of the electronic expansion valve based on the temperature difference; further, calculate the difference between the subcooling degree and the subcooling degree set value, i.e., the subcooling degree difference, based on the subcooling degree difference; determine the target opening degree of the electronic expansion valve based on the subcooling degree difference; adjust the opening degree of the electronic expansion valve to the target opening degree to reduce the proportion of gaseous refrigerant, thereby reducing the refrigerant flow noise and improving the user experience.

[0021] A second aspect of this application provides an electronic expansion valve control device, comprising: a reading unit for reading a temperature difference value, wherein the temperature difference value is the difference between the temperature of the intermediate two-phase portion of the indoor unit heat exchanger and the outlet temperature; a retrieving unit for retrieving the subcooling degree of the electronic expansion valve corresponding to the temperature difference value; calculating a subcooling degree difference value, wherein the subcooling degree difference value is the difference between the subcooling degree and the subcooling degree set value; a determining unit for determining a target opening degree of the electronic expansion valve based on the subcooling degree difference value; and an adjusting unit for adjusting the opening degree of the electronic expansion valve to the target opening degree to reduce the proportion of gaseous refrigerant.

[0022] In conjunction with the first implementation of the second aspect, the control device includes a reading unit for reading the status of the indoor unit; if the status of the indoor unit is operating: the step of determining the target opening of the electronic expansion valve based on the subcooling difference includes: if the subcooling difference is greater than a first subcooling constant, then the target opening is greater than the current opening of the electronic expansion valve; if the subcooling difference is between the first subcooling constant and zero, then the target opening is equal to the current opening of the electronic expansion valve; if the subcooling difference is less than zero, then the target opening is less than the current opening of the electronic expansion valve.

[0023] In conjunction with the second implementation method of the second aspect, if the indoor unit is in a non-operating state: the step of determining the target opening of the electronic expansion valve based on the subcooling difference also includes: if the subcooling difference is less than or equal to the second subcooling constant, the target opening is less than the current opening of the electronic expansion valve; if the subcooling difference is greater than the subcooling constant, the target opening is equal to the current opening of the electronic expansion valve.

[0024] In conjunction with the third implementation method of the second aspect, the reading unit is also used to: read the temperature difference value at predetermined intervals.

[0025] Combining the fourth implementation method of the second aspect, the second subcooling constant is greater than the first subcooling constant.

[0026] In conjunction with the fifth implementation method of the second aspect, the device also includes an adjustment unit: used to adjust the opening of the electronic expansion valve to an initial value in response to starting the multi-split air conditioning system; the initial value is related to the capacity of the indoor unit and the status of the indoor unit.

[0027] In conjunction with the sixth implementation method of the second aspect, the reading unit is also used to read the compressor operating frequency and the target frequency carried in the command in response to the compressor frequency adjustment command; the adjustment unit is also used to increase the opening of the electronic expansion valve and then increase the compressor frequency if the compressor operating frequency is less than the target frequency.

[0028] In conjunction with the seventh implementation method of the second aspect, the adjustment unit is also used to reduce the compressor frequency first and then reduce the opening of the electronic expansion valve if the compressor operating frequency is greater than the target frequency.

[0029] The beneficial effects described in the second aspect can be referred to the analysis of the beneficial effects in the first aspect, and will not be repeated here.

[0030] This application also provides a multi-split air conditioning system, including: an electronic expansion valve, a controller, and at least one indoor unit; the controller is configured to: execute the control method provided in the first aspect.

[0031] The beneficial effects described in the third aspect can be referred to in the analysis of the beneficial effects in the first aspect, and will not be repeated here. Attached Figure Description

[0032] The accompanying drawings are provided to further understand the technical solutions of the present invention and constitute a part of the specification. They are used together with the embodiments of this application to explain the technical solutions of the present invention and do not constitute a limitation on the technical solutions of the present invention.

[0033] Figure 1 This application provides a schematic diagram of the structure of a multi-split air conditioning system as an embodiment of the present application.

[0034] Figure 2 A flowchart illustrating a control method for reducing refrigerant noise in an electronic expansion valve, provided as an embodiment of this application;

[0035] Figure 3 A schematic diagram of the location for obtaining the indoor unit temperature according to an embodiment of this application;

[0036] Figure 4 The refrigerant pressure-enthalpy diagram provided for the embodiments of this application;

[0037] Figure 5 A flowchart of an electronic expansion valve control method provided in this application embodiment;

[0038] Figure 6 A flowchart of another electronic expansion valve control method provided in the embodiments of this application;

[0039] Figure 7 A flowchart of another electronic expansion valve control method provided in the embodiments of this application;

[0040] Figure 8 A structural block diagram of an electronic expansion valve control device provided in an embodiment of this application;

[0041] Figure 9 This is a structural block diagram of a multi-split air conditioning system provided in an embodiment of this application. Detailed Implementation

[0042] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0043] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0044] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "connected" and "linked" should be interpreted broadly, for example, as a fixed connection, a detachable connection, or an integral connection. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances. Furthermore, when describing pipelines, the terms "connected" and "linked" as used in this application have the meaning of establishing electrical connection. The specific meaning needs to be understood in conjunction with the context.

[0045] In the embodiments of this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design that is described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design. Specifically, the use of the terms "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0046] Figure 1 The illustration shows a multi-split air conditioning system provided in this application embodiment. This multi-split air conditioning system can also be referred to as a "one-to-many" air conditioning system. Typically, a multi-split air conditioning system includes a multi-split outdoor unit and at least one multi-split indoor unit. The outdoor unit is connected to two or more indoor units via piping. For ease of description, in this application embodiment, the outdoor unit can be referred to as the outdoor unit, and the indoor unit as the indoor unit.

[0047] This application does not specifically limit the temperature regulation methods of the indoor and outdoor units. As one feasible method, the outdoor unit of a multi-split air conditioning system can use air-cooled heat exchange to regulate the temperature. As another feasible method, the indoor unit of a multi-split air conditioning system can use direct evaporative heat exchange to regulate the temperature.

[0048] The multi-split air conditioning system will be further explained below with reference to the accompanying drawings. Please refer to... Figure 1 , Figure 1 This is a schematic diagram of a multi-split air conditioning system provided as a feasible embodiment.

[0049] like Figure 1 As shown, a multi-split air conditioning system may include: 1. Compressor; 2. Four-way reversing valve; 3. Outdoor unit heat exchanger; 4. Outdoor machine electronic expansion valve (EVO); 5. Liquid-side shut-off valve; 6. Indoor machine electronic expansion valve (EVI); 7. Indoor unit heat exchanger; 8. Indoor fan; 9. Gas-side shut-off valve; 10. Gas-liquid separator; 11. Figure 1 Only some components of the multi-split air conditioning system are shown; other components not shown may also be present in the multi-split air conditioning system.

[0050] It is worth noting that, Figure 1 This is merely an illustrative example of a multi-split air conditioning system including two indoor units. In actual applications, this application does not impose a specific limitation on the number of indoor units included in a multi-split air conditioning system.

[0051] In this embodiment, the compressor 1 is configured between the four-way reversing valve 2 and the gas-liquid separator 11 to compress the refrigerant and input the compressed refrigerant into the circulation system through the four-way reversing valve 2 to provide power for the circulation of the refrigerant.

[0052] The following explanation of the compressor's function is based on the example of refrigerant circulation in heating mode: In heating mode, compressor 1 can deliver the compressed refrigerant to the indoor unit heat exchanger 8 via the four-way reversing valve 2.

[0053] Optionally, compressor 1 can be a variable-capacity inverter compressor with speed control based on the inverter.

[0054] In this embodiment, the four ports (C, D, S, E) of the four-way reversing valve 2 are respectively connected to the exhaust port of the compressor 1 (not shown in the figure), the outdoor unit heat exchanger 3, the gas-liquid separator 11, and the indoor unit heat exchanger of each indoor unit.

[0055] The four-way reversing valve 2 is used to switch between cooling and heating modes in a multi-split air conditioning system by changing the flow direction of refrigerant in the system pipeline.

[0056] In this embodiment, one end of the outdoor unit heat exchanger 3 is connected to the compressor 1 via a four-way reversing valve 2, and the other end is connected to the indoor unit heat exchanger. The outdoor unit heat exchanger 3 is used to facilitate heat exchange between the refrigerant flowing in the heat transfer tubes of the outdoor unit heat exchanger 3 and the outdoor air, thereby achieving the purpose of temperature regulation.

[0057] In this embodiment, the outdoor fan 4 is connected to an outdoor fan (not shown in the figure) to drive or change the speed of the outdoor fan, so as to promote the heat exchange between the refrigerant flowing in the heat transfer tube of the outdoor unit heat exchanger 3 and the outdoor air, thereby achieving the purpose of auxiliary temperature regulation.

[0058] In this embodiment, the outdoor unit electronic expansion valve (EVO) 5 and the indoor unit electronic expansion valve (EVI) 7 are disposed between the indoor unit heat exchanger 8 and the outdoor unit heat exchanger 3. The outdoor unit electronic expansion valve (EVO) 5 has the function of expanding and depressurizing the refrigerant flowing through it, and can be used to regulate the flow rate of the refrigerant in the pipeline. Similarly, the indoor unit electronic expansion valve (EVI) 7 has the function of expanding and depressurizing the refrigerant flowing through the outdoor unit electronic expansion valve (EVO) 5, and can be used to regulate the flow rate of the refrigerant in the pipeline.

[0059] In this embodiment, if the electronic expansion valves (outdoor unit electronic expansion valve 5 and indoor unit electronic expansion valve 7) decrease their opening, the flow resistance of the refrigerant through the electronic expansion valves increases. If the electronic expansion valves increase their opening, the flow resistance of the refrigerant through the electronic expansion valves decreases. Thus, even if the states of other components in the multi-split air conditioning system remain unchanged, the refrigerant flow rate to the indoor unit heat exchanger 8 or the outdoor unit heat exchanger 3 will change when the opening of the electronic expansion valves changes.

[0060] It is worth noting that, Figure 1 This is merely an illustrative example of an application scenario where a multi-split air conditioning system includes one outdoor unit electronic expansion valve (EVO) 5 and two indoor unit electronic expansion valves (EVI) 7. The above application scenario does not constitute a limitation. In actual application, the number of outdoor unit electronic expansion valves (EVO) 5 and indoor unit electronic expansion valves (EVI) 7 can be set according to needs. The applicant will not impose any further limitations here.

[0061] In this embodiment, the liquid-side shut-off valve 6 is disposed between the outdoor unit electronic expansion valve (EVO) 5 and the indoor unit electronic expansion valve (EVI) 7.

[0062] In this embodiment, the indoor unit heat exchanger 8 is used to enable heat exchange between the refrigerant flowing in the heat transfer tube of the indoor heat exchanger 8 and the indoor air.

[0063] In this embodiment, the indoor fan 9 is connected to an indoor fan (not shown in the figure) to drive or change the speed of the indoor fan, so as to promote the heat exchange between the refrigerant flowing in the heat transfer tube of the indoor unit heat exchanger 8 and the indoor air.

[0064] In this embodiment, the gas-side shut-off valve 10 is disposed between the compressor assembly and the indoor unit heat exchanger 8.

[0065] In this embodiment, the gas-liquid separator 11 is connected to the compressor 1 and is used to separate gaseous refrigerant and liquid refrigerant.

[0066] In some embodiments, the multi-split air conditioning system also includes a remote control, which has the function of communicating with the controller, for example, using infrared or other communication methods. The remote control allows the user to perform various controls on the multi-split air conditioning system, enabling interaction between the user and the system.

[0067] Optionally, multi-split air conditioning systems may also include load regulating valves, temperature sensors, pressure sensors, and outdoor throttling devices, which will not be elaborated here.

[0068] In the embodiments shown in this application, the multi-split air conditioning system may further include a controller (not shown in the figures). The controller refers to a device that generates operation control signals based on instruction opcodes and timing signals, instructing the multi-split air conditioning system to execute control commands. Exemplarily, the controller may be a central processing unit (CPU), a network processor (NP), a digital signal processor (DSP), a microprocessor, a microcontroller, a programmable logic device (PLD), or any combination thereof. The controller may also be other devices with processing functions, such as circuits, devices, or software modules; this application does not impose any limitations on these aspects.

[0069] In addition, the controller can be used to control the operation of various components inside the multi-split air conditioning system, so that the operation of each component of the multi-split air conditioning system can realize the predetermined functions of the multi-split air conditioning system.

[0070] Those skilled in the art will understand that Figure 1 The hardware structure shown does not constitute a limitation on the multi-split air conditioning system. A multi-split air conditioning system may include more or fewer components than shown, or combine certain components, or have different component arrangements. It should be noted that... Figure 1 The number of indoor unit heat exchangers 8 and indoor unit electronic expansion valves (EVI) 7 shown is merely an example, and this application does not impose any specific limitations on them.

[0071] As living standards improve, multi-split air conditioning systems have gradually entered thousands of households. Besides demanding good cooling and heating performance, users are also concerned about the comfort of using these systems. Noise reduction is an important aspect of enhancing the comfort of multi-split air conditioning systems.

[0072] Due to the complex operating environment, there is a certain probability that the refrigerant will exist in a two-phase state when flowing through the electronic expansion valve, that is, a mixture of gaseous and liquid refrigerant. Since the electronic expansion valve is a throttling component, when gaseous and liquid refrigerant flow through the electronic expansion valve, the cross-sectional area through which the refrigerant passes suddenly becomes smaller, which can easily lead to changes in the fluid state of the refrigerant, thereby generating refrigerant flow noise.

[0073] Currently, adjusting the opening of the electronic expansion valve is based on experience or the compressor's power. However, in actual use, due to the complex operating environment of multi-split air conditioning systems, adjusting the electronic expansion valve opening based on experience cannot cope with frequent mode changes. When the indoor unit frequently changes modes, the refrigerant flowing through the electronic expansion valve, a throttling component, will produce intermittent refrigerant flow noise. This refrigerant flow noise is mostly high-frequency or intermittent, and users are very sensitive to high-frequency and intermittent noise. At high fan speeds, the refrigerant flow noise is less noticeable due to the fan's "masking effect," but it is stronger when running at low fan speeds (or silent mode) for sleep mode, resulting in a reduced user experience.

[0074] To address the aforementioned technical problems, this application provides a control method for an electronic expansion valve, applicable to the above-mentioned... Figure 1 Multi-split air conditioning systems are used to regulate Figure 1 The indoor unit's electronic expansion valve 7, such as Figure 2 As shown, the control method includes the following steps S201 to S205:

[0075] S201. Read the temperature difference value. The temperature difference value is the difference between the temperature of the two phases in the middle of the heat exchanger of the indoor unit and the outlet temperature.

[0076] Please see Figure 3 , Figure 3 This is a schematic diagram of a heat exchanger for an indoor unit provided in a feasible embodiment. The indoor unit heat exchanger 8 is used to facilitate heat exchange between the refrigerant flowing inside the heat transfer tubes of the indoor heat exchanger 8 and the indoor air.

[0077] Among them, the temperature of the intermediate two-phase section and the outlet temperature of the indoor unit heat exchanger are obtained from the following locations: Figure 3 As shown: TL is the temperature of the middle two phases of the heat exchanger, and TC is the location where the outlet temperature is obtained.

[0078] As a feasible approach, temperature sensors can be installed in the middle of the indoor unit heat exchanger and at the inlet pipe of the indoor unit heat exchanger, and then the temperature of the middle two-phase part and the outlet temperature of the indoor unit heat exchanger can be obtained based on the temperature sensors.

[0079] S202. Determine the subcooling of the electronic expansion valve based on the temperature difference.

[0080] In this embodiment of the application, the degree of undercooling can be represented by SC.

[0081] Subcooling refers to the difference between the temperature of the refrigerant and its saturation temperature at a given pressure. Please refer to [link / reference]. Figure 4 , Figure 4 This is a pressure-enthalpy diagram provided for a feasible embodiment. The vertical axis of the diagram represents pressure P, in Pascals (Pa), and the horizontal axis represents specific enthalpy h, i.e., the enthalpy of 1 kg of a substance, in kJ / kg. The subcooling SC can be expressed as the difference between the temperature T6 of the high-pressure saturated refrigerant (the temperature corresponding to the refrigerant in state ⑥ in the diagram) and the condenser outlet temperature T2 (the temperature corresponding to the refrigerant in state ② in the diagram): SC = T6 - T2.

[0082] In this embodiment, the temperature TC of the middle two-phase part of the indoor unit heat exchanger is used as the temperature T6 of the high-pressure saturated liquid, and the condenser outlet temperature T2 is selected as the detection temperature TL of the indoor unit heat exchanger outlet. Therefore, the subcooling of the electronic expansion valve can be expressed as: SC = TC - TL.

[0083] S203. Calculate the subcooling difference, which is the difference between the subcooling and the subcooling set value.

[0084] In this embodiment, the subcooling setting value is preset by the system. In actual application, the subcooling setting value can be set according to requirements. For example, as a feasible implementation method, the subcooling setting value ranges from (0 to 20), preferably from (1 to 5).

[0085] S204. Determine the target opening degree of the electronic expansion valve based on the subcooling difference.

[0086] In this embodiment, the correspondence between the subcooling difference and the electronic expansion valve opening is stored in the memory beforehand. When the controller completes the calculation of the subcooling difference, it retrieves the target opening based on the stored correspondence between the subcooling difference and the electronic expansion valve opening.

[0087] S205. Adjust the opening of the electronic expansion valve to the target opening to reduce the proportion of gaseous refrigerant.

[0088] The controller method provided in this application allows the controller to calculate the temperature difference between the temperature of the two intermediate phases of the indoor unit heat exchanger and the outlet temperature. Then, based on the temperature difference, the subcooling degree of the electronic expansion valve is determined. Further, based on the subcooling degree, the difference between the subcooling degree and the subcooling degree setpoint is calculated, i.e., the subcooling degree difference. Based on the subcooling degree difference, the target opening degree of the electronic expansion valve is determined. The opening degree of the electronic expansion valve is adjusted to the target opening degree to reduce the proportion of gaseous refrigerant, thereby reducing refrigerant flow noise and improving the user experience.

[0089] To adapt to the electronic expansion valve under different conditions, the embodiments of this application have further improved the adjustment method of the electronic expansion valve, specifically:

[0090] In some feasible implementations, the status of all indoor units needs to be read before reading the temperature difference value. If the indoor unit is in the running state, then... Figure 5 As shown, S204 can be specifically implemented as follows:

[0091] S502. Determine whether the subcooling difference is less than or equal to the first subcooling constant.

[0092] S5031. If not, the target opening degree is greater than the current opening degree of the electronic expansion valve.

[0093] Specifically, EVI(N+1) = EVI(N) + ΔEVI. Wherein, EVI(N+1) is the target opening degree, EVI(N) is the current opening degree of the electronic expansion valve, and ΔEVI can be set according to requirements. This application embodiment does not impose any restrictions on this.

[0094] S5032. If so, determine whether the subcooling difference is greater than zero.

[0095] S5041. If the subcooling difference is greater than zero, that is, the subcooling difference is between the first subcooling constant and zero, then the target opening is equal to the current opening of the electronic expansion valve.

[0096] Specifically, EVI(N+1) = EVI(N).

[0097] S5042. If the subcooling difference is less than zero, the target opening is less than the current opening of the electronic expansion valve.

[0098] Specifically, EVI(N+1) = EVI(N) - ΔEVI.

[0099] In this implementation, before adjusting the opening of the electronic expansion valve, the status of the indoor unit is read in advance. If the indoor unit is running, and the subcooling difference is greater than the first subcooling constant, the opening of the electronic expansion valve can be appropriately increased to ensure the temperature regulation efficiency of the multi-split air conditioning system. If the indoor unit is running, and the subcooling difference is less than or equal to the first subcooling constant, in order to balance the temperature regulation efficiency of the multi-split air conditioning system, the controller needs to determine whether the subcooling difference is greater than zero. If the subcooling difference is greater than zero, that is, the subcooling difference is between the first subcooling constant and zero, the opening of the electronic expansion valve is kept constant to ensure the temperature regulation efficiency of the multi-split air conditioning system. If the subcooling difference is less than or equal to zero, the opening of the electronic expansion valve is reduced to reduce refrigerant flow noise.

[0100] As a feasible implementation method, if the indoor unit is in a non-operating state, then such as Figure 6 As shown, S204 can be specifically implemented as follows:

[0101] S602. Determine whether the subcooling difference is less than or equal to the second subcooling constant.

[0102] S6031, If ​​so, the target opening degree is less than the current opening degree of the electronic expansion valve.

[0103] Specifically, EVI(N+1) = EVI(N) - ΔEVI.

[0104] S6032. If not, the target opening is equal to the current opening of the electronic expansion valve.

[0105] Specifically, EVI(N+1) = EVI(N).

[0106] In this implementation, before adjusting the opening of the electronic expansion valve, the status of the indoor unit is read in advance. If the indoor unit is not in operation, it is only necessary to determine the relationship between the subcooling difference and the second subcooling constant. When the subcooling difference is less than or equal to the second subcooling constant, the opening of the electronic expansion valve can be directly reduced to decrease the refrigerant flow noise. When the subcooling difference is less than or equal to the second subcooling constant, the opening of the electronic expansion valve is kept constant to ensure the efficiency of temperature regulation in the multi-split air conditioning system. As a feasible implementation, the controller can reread the temperature difference at predetermined intervals and adjust the opening of the electronic expansion valve accordingly.

[0107] It is worth noting in this embodiment that the shorter the preset time, the more significant the effect of the multi-split air conditioning system in reducing refrigerant flow noise; however, a shorter preset time will correspondingly increase the computational load on the controller. In practical applications, the preset time can be determined according to requirements, and the applicant does not impose excessive limitations here. For example, in a feasible embodiment, the preset time could be 20 seconds.

[0108] In this implementation, the controller rereads the temperature difference value at predetermined intervals to adjust the opening of the electronic expansion valve in a timely manner, preventing refrigerant with low subcooling from flowing through the electronic expansion valve and generating refrigerant flow noise. In some embodiments, the second subcooling constant corresponding to the indoor unit in the non-operating state is greater than the first subcooling constant corresponding to the indoor unit in the operating state. For the indoor unit in the non-operating state, because the indoor fan is off and the indoor unit heat exchanger cannot perform effective heat exchange, its corresponding second subcooling constant needs to be greater than the first subcooling constant corresponding to the indoor unit in the operating state. The first subcooling constant can be represented by g1, with a value range of (3, 6), and the second subcooling constant can be represented by g2, with a value range of (5, 10).

[0109] It is understood that the first subcooling constant and the second subcooling constant can be set according to requirements, and the embodiments of this application do not impose any restrictions on this.

[0110] In some embodiments, in response to a user activating the multi-split air conditioning system, the opening of the electronic expansion valve can be adjusted to its initial value. The initial value for indoor units in non-operational state is EVI0, and the initial value for indoor units in operation state is EVI01. In some feasible implementations, EVI0 and EVI01 may be the same or different.

[0111] EVI0 and EVI01 can be set according to requirements, and this application embodiment does not impose any restrictions on them.

[0112] For example, as a feasible approach, EVI0 and EVI01 can be set according to the capacity of the multi-split air conditioning system. Typically, the values ​​of EVI0 and EVI01 are positively correlated with the capacity of the multi-split air conditioning system.

[0113] For example, as a feasible approach, EVI0 and EVI01 can be set based on the number of indoor units in a multi-split air conditioning system. Typically, the values ​​of EVI0 and EVI01 are positively correlated with the number of indoor units.

[0114] To further improve the refrigerant flow noise reduction effect of multi-split air conditioning systems, based on the solution provided in the above embodiments, the control method further includes:

[0115] based on Figure 7 In the illustrated embodiment, the compressor frequency needs to be adjusted when the indoor unit control mode changes. This application uses the following method when receiving a compressor frequency adjustment instruction:

[0116] S701. Compare the current operating frequency Ft of the compressor with the target frequency Fn.

[0117] S7021. If Ft < Fn, that is, when the compressor needs to increase the frequency, first increase the opening of the electronic expansion valve to the target opening, and then execute S7031.

[0118] Specifically, EVI(N + 1) = EVI(N) + △EVI.

[0119] S7022. If Ft > Fn, that is, when the compressor needs to decrease the frequency, first decrease the compressor frequency to the target frequency Fn, and then execute S7032.

[0120] S7031. Increase the compressor frequency to the target frequency Fn.

[0121] S7032. Then decrease the opening of the electronic expansion valve to the target opening.

[0122] Specifically, EVI(N + 1) = EVI(N) - △EVI.

[0123] This can avoid the generation of strong compression waves of the refrigerant at the electronic expansion valve when the compressor frequency changes, causing noise in the indoor unit.

[0124] Please refer to Figure 8 , an electronic expansion valve control device provided by an embodiment of the present application includes: a reading unit 81 for reading the temperature difference, where the temperature difference is the difference between the temperature of the middle two-phase part of the indoor unit heat exchanger and the outlet temperature; a retrieval unit 82 for retrieving the superheat degree of the electronic expansion valve corresponding to the temperature difference; a calculation unit 83 for calculating the superheat degree difference, where the superheat degree difference is the difference between the superheat degree and the set value of the superheat degree; a determination unit 84 for determining the target opening of the electronic expansion valve according to the superheat degree difference; and an adjustment unit 85 for adjusting the opening of the electronic expansion valve to the target opening to reduce the proportion of gaseous refrigerant.

[0125] As a feasible implementation manner, the electronic expansion valve control device includes a state reading unit for reading the state of the indoor unit; if the state of the indoor unit is the operating state: according to the superheat degree difference, if the superheat degree difference is greater than the first superheat degree constant, the target opening is greater than the current opening of the electronic expansion valve; if the superheat degree difference is between the first superheat degree constant and zero, the target opening is equal to the current opening of the electronic expansion valve; if the superheat degree difference is less than zero, the target opening is less than the current opening of the electronic expansion valve.

[0126] As a feasible implementation manner, if the state of the indoor unit is the non-operating state: if the superheat degree difference is less than or equal to the second superheat degree constant, the target opening is less than the current opening of the electronic expansion valve; if the superheat degree difference is greater than the superheat degree constant, the target opening is equal to the current opening of the electronic expansion valve.

[0127] As a feasible implementation manner, the reading unit is further configured to: read the temperature difference at a preset time interval.

[0128] As a feasible approach, the second subcooling constant is greater than the first subcooling constant.

[0129] As a feasible implementation method, the device also includes an adjustment unit for adjusting the opening of the electronic expansion valve to an initial value in response to starting the multi-split air conditioning system; the initial value is related to the capacity and status of the indoor unit.

[0130] As a feasible implementation method, the reading unit is also used to read the compressor operating frequency and the target frequency carried by the command in response to the compressor frequency adjustment command; the adjustment unit is also used to increase the opening of the electronic expansion valve and then increase the compressor frequency if the compressor operating frequency is less than the target frequency.

[0131] As a feasible implementation method, the adjustment unit is also used to reduce the compressor frequency first and then reduce the opening of the electronic expansion valve if the compressor operating frequency is greater than the target frequency.

[0132] This application also provides a multi-split air conditioning system. Please refer to [link to relevant documentation]. Figure 9 The multi-split air conditioning system includes a controller 91; a memory 92 for storing executable instructions of the controller 91; wherein the controller 91 is configured to execute instructions to implement the control method provided in the embodiments of this application.

[0133] Optionally, the computer-readable storage medium may be a non-transitory computer-readable storage medium, such as a read-only memory (ROM), random access memory (RAM), CD-ROM, magnetic tape, floppy disk, and optical data storage device.

[0134] In an exemplary embodiment, this application also provides a computer program product including one or more instructions, which can be executed by the controller 91 of the multi-split air conditioning system to complete the control method described above.

[0135] It should be noted that when one or more instructions in the computer-readable storage medium or computer program product are executed by the controller, they implement the various processes of the above-described control method embodiments and achieve the same technical effect as the above-described control method. To avoid repetition, they will not be described again here.

[0136] Through the above description of the embodiments, those skilled in the art can clearly understand that, for the sake of convenience and brevity, only the division of the above functional modules is used as an example. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.

[0137] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another apparatus, or some features may be ignored or not executed. Furthermore, the mutual coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0138] The units described as separate components may or may not be physically separate. A component shown as a unit can be one or more physical units; that is, it can be located in one place or distributed in multiple different locations. Some or all of the classified units can be selected to achieve the purpose of this embodiment, depending on actual needs.

[0139] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0140] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a readable storage medium. Based on this understanding, the technical solution of the embodiments of this application, essentially, or the part that contributes to the prior art, or a complete or partial classification of the technical solution, can be embodied in the form of a software product. This software product is stored in a storage medium and includes several instructions to cause a device (which may be a microcontroller, chip, etc.) or processor to execute all or part of the steps of the methods of the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, ROM, RAM, magnetic disks, or optical disks.

[0141] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for controlling an electronic expansion valve, characterized in that, include: Read the status of the indoor unit; If the indoor unit is in the running state, read the temperature difference value. The temperature difference value is the difference between the temperature of the two intermediate phases of the indoor unit heat exchanger and the outlet temperature. The temperature of the two intermediate phases of the indoor unit heat exchanger is used to represent the temperature of the high-pressure saturated liquid in the indoor unit heat exchanger. The subcooling of the electronic expansion valve is determined based on the temperature difference. Calculate the subcooling difference, which is the difference between the subcooling degree and the subcooling set value; Based on the subcooling difference, determine the target opening degree of the electronic expansion valve; Adjust the opening of the electronic expansion valve to the target opening to reduce the proportion of gaseous refrigerant; The step of determining the target opening degree of the electronic expansion valve based on the subcooling difference includes: If the subcooling difference is greater than the first subcooling constant, then the target opening is greater than the current opening of the electronic expansion valve; If the subcooling difference is between the first subcooling constant and zero, then the target opening is equal to the current opening of the electronic expansion valve; If the subcooling difference is less than zero, then the target opening is less than the current opening of the electronic expansion valve; The control method further includes: In response to a compressor frequency adjustment command, the compressor operating frequency and the target frequency carried by the command are read. If the compressor operating frequency is lower than the target frequency, first increase the opening of the electronic expansion valve and then increase the compressor frequency. If the compressor operating frequency is greater than the target frequency, first reduce the compressor frequency and then reduce the opening of the electronic expansion valve.

2. The control method according to claim 1, characterized in that, The control method further includes: If the indoor unit is in a non-operating state: The step of determining the target opening degree of the electronic expansion valve based on the subcooling difference further includes: If the subcooling difference is less than or equal to the second subcooling constant, then the target opening is less than the current opening of the electronic expansion valve; If the subcooling difference is greater than the second subcooling constant, then the target opening is equal to the current opening of the electronic expansion valve.

3. The control method according to claim 2, characterized in that, The second subcooling constant is greater than the first subcooling constant.

4. The control method according to any one of claims 2 to 3, characterized in that, The control method further includes: The temperature difference is read at predetermined intervals.

5. The control method according to claim 4, characterized in that, The control method further includes: In response to starting the multi-split air conditioning system, the opening of the electronic expansion valve is adjusted to an initial value; the initial value is related to the capacity of the indoor unit and the status of the indoor unit.

6. An electronic expansion valve control device, characterized in that, include: Read the unit to read the status of the indoor unit; If the indoor unit is in the running state, it is used to read the temperature difference value, which is the difference between the temperature of the two intermediate phases of the indoor unit heat exchanger and the outlet temperature; the temperature of the two intermediate phases of the indoor unit heat exchanger is used to represent the temperature of the high-pressure saturated liquid in the indoor unit heat exchanger. The retrieval unit is used to retrieve the subcooling of the electronic expansion valve corresponding to the temperature difference value; A calculation unit is used to calculate the subcooling difference, wherein the subcooling difference is the difference between the subcooling degree and the subcooling set value; The determining unit is configured to determine that if the subcooling difference is greater than the first subcooling constant, the target opening is greater than the current opening of the electronic expansion valve. If the subcooling difference is between the first subcooling constant and zero, then the target opening is equal to the current opening of the electronic expansion valve; If the subcooling difference is less than zero, then the target opening is less than the current opening of the electronic expansion valve; The adjustment unit is used to adjust the opening of the electronic expansion valve to the target opening to reduce the proportion of gaseous refrigerant; The reading unit is also used to read the compressor operating frequency and the target frequency carried by the command in response to the compressor frequency adjustment command; The adjustment unit is configured to, if the compressor operating frequency is less than the target frequency, first increase the opening of the electronic expansion valve and then increase the compressor frequency; if the compressor operating frequency is greater than the target frequency, first decrease the compressor frequency and then decrease the opening of the electronic expansion valve.

7. A multi-split air conditioning system, characterized in that, include: Electronic expansion valve, controller and at least one indoor unit; The controller is configured to: Read the status of the indoor unit; If the indoor unit is in the running state, read the temperature difference value. The temperature difference value is the difference between the temperature of the middle two-phase part of the heat exchanger of the indoor unit and the outlet temperature. The temperature of the middle two-phase part of the heat exchanger of the indoor unit is used to represent the temperature of the high-pressure saturated liquid in the heat exchanger of the indoor unit. The subcooling of the electronic expansion valve is determined based on the temperature difference. Calculate the subcooling difference, which is the difference between the subcooling degree and the subcooling set value; Based on the subcooling difference, determine the target opening degree of the electronic expansion valve; Adjust the opening of the electronic expansion valve to the target opening to reduce the proportion of gaseous refrigerant; The step of determining the target opening degree of the electronic expansion valve based on the subcooling difference includes: If the subcooling difference is greater than the first subcooling constant, then the target opening is greater than the current opening of the electronic expansion valve; If the subcooling difference is between the first subcooling constant and zero, then the target opening is equal to the current opening of the electronic expansion valve; If the subcooling difference is less than zero, then the target opening is less than the current opening of the electronic expansion valve; The controller is also configured to: In response to a compressor frequency adjustment command, the compressor operating frequency and the target frequency carried by the command are read. If the compressor operating frequency is lower than the target frequency, first increase the opening of the electronic expansion valve and then increase the compressor frequency. If the compressor operating frequency is greater than the target frequency, first reduce the compressor frequency and then reduce the opening of the electronic expansion valve.

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