Multi-split air conditioning system and control method thereof

Abstract

The invention relates to the technical field of variable frequency air conditioners, and discloses a multi-split air conditioner system and a control method thereof.The multi-split air conditioner system comprises an outdoor unit and a plurality of indoor units, and the control method comprises the steps that when the multiple indoor units start a refrigeration mode or a heating mode at the same time, an electronic expansion valve of each indoor unit is controlled to be opened at the initial opening degree; the opening degree of each electronic expansion valve is adjusted according to the target exhaust temperature when the multi-split air conditioning system meets the first preset condition, the opening degree of each electronic expansion valve is adjusted according to the target coil pipe temperature when the actual exhaust temperature of the outdoor unit meets the second preset condition, and the opening degree of each electronic expansion valve is adjusted according to the target coil pipe temperature when the actual exhaust temperature of the outdoor unit meets the third preset condition. And the opening degree of each electronic expansion valve is adjusted according to the target exhaust temperature. The control strategy of the electronic expansion valve can be switched in stages according to the state of the multi-split air conditioner system, stage control better fits the operation characteristics of the system, and it is guaranteed that the temperature coordination effect of all rooms is consistent.

Description

Technical Field

[0001] The present application relates to the technical field of variable frequency air conditioning control, and in particular to a one-to-many air conditioning system and a control method thereof. Background Art

[0002] In a multi-split air conditioning system, the outdoor unit controls the refrigerant flow to multiple indoor units through multiple electronic expansion valves. However, existing electronic expansion valve control methods suffer from slow system response during the initial compressor startup. This, coupled with differences in heat load and piping length between the indoor units, results in slow heating or cooling efficiency and inconsistent cooling / heating performance across rooms. This can cause some rooms to be too cold or too hot, and others to be unevenly cooled or heated. Summary of the Invention In view of this, the embodiments of the present application provide a one-to-many air-conditioning system and a control method thereof, which can effectively solve the problems of poor cooling or heating effects and low efficiency in multi-split air-conditioning systems.

[0003] In a first aspect, an embodiment of the present application provides a control method for a one-to-many air conditioning system, wherein the one-to-many air conditioning system includes an outdoor unit and multiple indoor units, and the control method includes: When the plurality of indoor units of the one-to-many air-conditioning system are simultaneously turned on in cooling mode or heating mode, controlling the electronic expansion valve of each indoor unit to open at an initial opening; When the one-to-many air conditioning system satisfies a first preset condition, calculating a target exhaust temperature of the outdoor unit in the cooling mode or the heating mode; wherein the first preset condition is a trigger basis for adjusting the actual exhaust temperature of the outdoor unit; The opening of each electronic expansion valve is adjusted according to the target exhaust temperature to adjust the actual exhaust temperature of the outdoor unit to be close to the target exhaust temperature.

[0004] In a first possible embodiment of the first aspect, the further comprising: When the actual exhaust temperature of the outdoor unit meets a second preset condition, the average value of the indoor coil temperatures of each of the indoor units is used as the target coil temperature; the second preset condition is a trigger basis for adjusting the indoor coil temperature of the indoor unit; adjusting the opening of each electronic expansion valve according to the target coil temperature to adjust the indoor coil temperature of each indoor unit to be consistent; When the actual exhaust temperature of the outdoor unit meets the third preset condition, the opening of each electronic expansion valve is adjusted again according to the target exhaust temperature; the third preset condition is the trigger basis for exiting the adjustment of the indoor coil temperature of the indoor unit and entering the adjustment of the actual exhaust temperature of the outdoor unit.

[0005] In a second possible embodiment of the first aspect, calculating the target exhaust temperature of the outdoor unit in the cooling mode or the heating mode includes: Under the heating mode, calculating a first target exhaust temperature of the outdoor unit based on a first target exhaust temperature calculation formula, so as to adjust the opening of each electronic expansion valve according to the first target exhaust temperature; Under the cooling mode, a second target exhaust temperature of the outdoor unit is calculated based on a second target exhaust temperature calculation formula, so as to adjust the opening of each electronic expansion valve according to the second target exhaust temperature.

[0006] In a third possible embodiment of the first aspect, the first preset condition is: The initial opening time of the electronic expansion valve is equal to the first preset time; Alternatively, in the heating mode, the actual exhaust temperature of the outdoor unit is greater than or equal to the initial target exhaust temperature and lasts for a second preset time; Alternatively, in the cooling mode, the return air superheat is greater than or equal to the first preset temperature and lasts for a third preset time, and the actual exhaust temperature of the outdoor unit is greater than or equal to the second preset temperature and lasts for a fourth preset time; wherein the return air superheat is the difference between the refrigerant gas temperature of the compressor entering the one-to-many air-conditioning system and the average value of the indoor coil temperature of each of the indoor units.

[0007] In a fourth possible embodiment of the first aspect, adjusting the opening of each electronic expansion valve according to the target exhaust temperature includes: Calculating an exhaust temperature difference, the exhaust temperature difference including a difference between an actual exhaust temperature of the outdoor unit at a current moment and a target exhaust temperature at a current moment, and a difference between an actual exhaust temperature at a previous moment and a target exhaust temperature at a previous moment; The number of opening adjustment steps of the electronic expansion valve at the current moment is calculated based on the exhaust temperature difference, so as to adjust the opening of each electronic expansion valve according to the number of opening adjustment steps at the current moment until the actual exhaust temperature of the outdoor unit is adjusted to near the target exhaust temperature.

[0008] In a fifth possible embodiment of the first aspect, the second preset condition is: a difference between the actual exhaust temperature of the outdoor unit and the target exhaust temperature is within a first preset range and lasts for a fifth preset time; The third preset condition is that the difference between the actual exhaust temperature of the outdoor unit and the target exhaust temperature is not within a second preset range.

[0009] In a sixth possible embodiment of the first aspect, the calculation formula for the first target exhaust temperature is:

[0010] represents the first target exhaust temperature in the heating mode, represents the frequency correlation coefficient in the heating mode, Indicates the actual operating frequency of the compressor in the one-to-many air-conditioning system in the heating mode, represents the indoor coil temperature correlation coefficient in the heating mode, represents the average value of the indoor coil temperature of each of the indoor units in the heating mode, Indicates the ground source water outlet temperature of the one-to-many air conditioning system in the heating mode, A correction term representing the actual operating frequency of the compressor; The calculation formula for the second target exhaust temperature is:

[0011] represents the second target exhaust temperature in the cooling mode, represents the frequency correlation coefficient during the cooling mode, Indicates the actual operating frequency of the compressor in the one-to-many air-conditioning system in the cooling mode, represents a correction term for the second target exhaust temperature in the cooling mode, Indicates the ground source water outlet temperature of the one-to-many air conditioning system in the cooling mode.

[0012] In a seventh possible embodiment of the first aspect, a calculation formula for the number of opening adjustment steps of the electronic expansion valve at a current moment is:

[0013] Indicates the number of opening adjustment steps at the current moment, represents the proportional gain coefficient of the closed-loop control algorithm, represents the actual exhaust temperature at the current moment, represents the target exhaust temperature at the current moment, represents the differential gain of the closed-loop control algorithm, Indicates the actual exhaust temperature at the previous moment, Indicates the target exhaust temperature at the previous moment.

[0014] In an eighth possible embodiment of the first aspect, the present invention further includes: The operating frequency of the compressor in the one-to-many air-conditioning system is controlled according to the operating number of the indoor units, wherein the operating frequency of the compressor is increased when the operating number of the indoor units increases, and the operating frequency of the compressor is reduced when the operating number of the indoor units decreases.

[0015] In a second aspect, an embodiment of the present application provides a one-to-many air-conditioning system, comprising an outdoor unit and multiple indoor units, wherein the one-to-many air-conditioning system is used to execute the above-mentioned control method of the one-to-many air-conditioning system.

[0016] The embodiments of the present application have the following beneficial effects: The present embodiment provides a control method for a one-to-many air-conditioning system, wherein the one-to-many air-conditioning system includes an outdoor unit and multiple indoor units. The control method includes: when multiple indoor units of the one-to-many air-conditioning system are simultaneously turned on in cooling mode or heating mode, controlling the electronic expansion valve of each indoor unit to open at an initial opening; when the one-to-many air-conditioning system meets a first preset condition, adjusting the opening of each electronic expansion valve according to a target exhaust temperature; when the actual exhaust temperature of the outdoor unit meets a second preset condition, adjusting the opening of each electronic expansion valve according to a target coil temperature; when the actual exhaust temperature of the outdoor unit meets a third preset condition, adjusting the opening of each electronic expansion valve again according to the target exhaust temperature. Based on the above scheme, the present application can switch the control strategy of the electronic expansion valve in stages according to the state of the one-to-many air-conditioning system. The staged control is more in line with the system operation characteristics, ensuring that the control response speed is improved at the initial stage of the indoor unit opening, and then adjusting the solenoid valve opening of each indoor unit according to the target exhaust temperature. The unified control of the solenoid valve opening can avoid uneven refrigerant distribution between rooms and improve the overall system coordination. Then, the opening of each electronic expansion valve is adjusted according to the target coil temperature, and the internal coil temperature of each indoor unit is adjusted to be consistent, so that the temperature control effect of each room is consistent. Finally, when the actual exhaust temperature of the outdoor unit meets the preset conditions, it can switch back to adjusting the solenoid valve opening of each indoor unit according to the target exhaust temperature to ensure cooling or heating efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 A schematic structural diagram of a one-to-many air conditioning system according to an embodiment of the present application is shown; Figure 2 A first flow chart of a control method for a one-to-many air conditioning system according to an embodiment of the present application is shown; Figure 3 A second flow chart of the control method of a one-to-many air-conditioning system according to an embodiment of the present application is shown.

[0019] Description of main component symbols: 100-One-to-many air conditioning system; 110-outdoor unit; 120-indoor unit. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments.

[0021] The components of the embodiments of the present application generally described and illustrated in the drawings herein may be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed application, but rather merely represents selected embodiments of the present application. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without creative effort are within the scope of protection of the present application.

[0022] Hereinafter, the terms "including", "having" and their cognates used in various embodiments of the present application are intended only to indicate specific features, numbers, steps, operations, elements, components or combinations of the aforementioned items, and should not be understood as excluding the existence of one or more other features, numbers, steps, operations, elements, components or combinations of the aforementioned items or adding the possibility of one or more features, numbers, steps, operations, elements, components or combinations of the aforementioned items. In addition, the terms "first", "second", "third" and the like are only used to distinguish descriptions and should not be understood as indicating or implying relative importance.

[0023] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by those skilled in the art to which the various embodiments of the present application belong. Terms (such as those defined in generally used dictionaries) will be interpreted as having the same meaning as in the context of the relevant technical field and will not be interpreted as having an idealized meaning or an overly formal meaning unless clearly defined in the various embodiments of the present application.

[0024] The following describes some embodiments of the present application in detail with reference to the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments may be combined with each other.

[0025] First, the embodiment of the present application provides a one-to-many air conditioning system 100. Figure 1, is a block diagram of the structure of a one-to-many air conditioning system 100 provided in an embodiment of the present application. The one-to-many air conditioning system 100 may include an outdoor unit 110 and multiple indoor units 120. The outdoor unit 110 may be electrically connected to each of the indoor units 120, either directly or indirectly, to enable data transmission and interaction. For example, the outdoor unit 110 and each of the indoor units 120 may be electrically connected to each other via a bus and / or signal lines.

[0026] In one embodiment, each indoor unit 120 is installed in a different room, providing cooling and heating for the corresponding room. The outdoor unit 110 includes a controller connected to the expansion valve of each indoor unit 120. The controller regulates the opening of the electronic expansion valve in each indoor unit 120 in cooling or heating mode. The controller appropriately controls the opening of the electronic expansion valve during initial compressor startup and dynamically switches control strategies based on the operating status of the one-to-many air conditioning system 100 to achieve efficient, stable, and balanced cooling / heating performance. The outdoor unit 110 also includes a compressor. In cooling or heating mode, the compressor compresses low-temperature, low-pressure refrigerant gas into high-temperature, high-pressure gas, which is then transported to the outdoor condenser for heat dissipation. The electronic expansion valve controls the refrigerant flow rate to the indoor evaporator to maintain an appropriate return air superheat. In heating mode, the compressor compresses refrigerant gas for heating, controlling the refrigerant flow rate to the outdoor evaporator to maintain an appropriate return air superheat. The controller may be an integrated circuit chip with signal processing capability, including but not limited to a central processing unit (CPU), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic devices.

[0027] For ease of understanding, the following examples of this application will be described in Figure 1 Taking the one-to-many air-conditioning system 100 shown as an example, in conjunction with Figure 1 , the control method of the one-to-many air-conditioning system 100 provided in an embodiment of the present application is explained.

[0028] Please refer to Figure 2 , Figure 2 A flow chart of a control method for a one-to-many air conditioning system 100 provided in an embodiment of the present application is shown. The control method for the one-to-many air conditioning system 100 may include the following steps: S210 , when the multiple indoor units 120 of the one-to-many air conditioning system 100 are simultaneously turned on in cooling mode or heating mode, the electronic expansion valve of each indoor unit 120 is controlled to open at an initial opening.

[0029] In this embodiment, when the corresponding indoor unit 120 receives a cooling / heating signal, the electronic expansion valve opens to an initial opening and maintains the current opening. If other rooms are still cooling or heating, but a room is not, the electronic expansion valve in that room will close. The initial opening can be determined based on the heat source side inlet water temperature range, with each range corresponding to an initial opening. The heat source side inlet water temperature refers to the inlet temperature of the circulating water flowing through the heat source side heat exchanger (for heat exchange with the outside world). The electronic expansion valve controls the opening range of 0~250P. When the inlet water temperature on the heat source side is ≤7℃, the initial opening setting range is 80P~100P. When the inlet water temperature on the heat source side is 8℃≤15℃, the initial opening setting range is 100P~150P. When the inlet water temperature on the heat source side is 16℃≤23℃, the initial opening setting range is 120P~200P. When the inlet water temperature on the heat source side is ≥24℃, the initial opening setting range is 140P~250P.

[0030] S220, when the one-to-many air conditioning system 100 meets the first preset condition, calculate the target exhaust temperature of the outdoor unit 110 in the cooling mode or the heating mode; wherein the first preset condition is the trigger basis for adjusting the actual exhaust temperature of the outdoor unit 110.

[0031] In one embodiment, the first preset condition is: the initial opening time of the electronic expansion valve is equal to the first preset time; or, in heating mode, the actual exhaust temperature of the outdoor unit 110 is greater than or equal to the initial target exhaust temperature and persists for a second preset time. Or, in cooling mode, the return air superheat is greater than or equal to the first preset temperature and persists for a third preset time, and the actual exhaust temperature of the outdoor unit 110 is greater than or equal to the second preset temperature and persists for a fourth preset time. The return air superheat is the difference between the refrigerant gas temperature entering the compressor of the one-to-many air conditioning system 100 and the average indoor coil temperature of each indoor unit 120. The actual exhaust temperature of the outdoor unit 110 refers to the temperature of the high-temperature, high-pressure refrigerant gas discharged from the compressor within the outdoor unit 110.

[0032] In this embodiment, the first preset condition includes three parallel trigger logics, each applicable to a different operating mode. In heating mode or cooling mode, when the initial opening time of the electronic expansion valve reaches the preset value, it can be considered that the refrigerant cycle has stabilized and the system has responded to cooling or heating. At this time, the target exhaust temperature of the outdoor unit is adjusted, which improves the heating efficiency and avoids misjudgment due to the system just starting up and being unstable. In heating mode, if the exhaust temperature of the outdoor unit 110 is higher than the initial target exhaust temperature for a long time, it means that the current compressor load is high. At this time, the opening of the electronic expansion valve needs to be dynamically adjusted to prevent exhaust gas overheating and damage to the compressor. In cooling mode, if the return air superheat is greater than or equal to the first preset temperature, and the actual exhaust temperature of the outdoor unit 110 is greater than or equal to the second preset temperature, it means that the system is under high load operation. If the duration is too long, it may cause insufficient heat dissipation of the compressor, causing high temperature. At this time, the opening of the electronic expansion valve needs to be dynamically adjusted to prevent the compressor from continuing to operate at high temperature.

[0033] In one embodiment, the first preset temperature, the second preset temperature, the first preset time, the second preset time, the third preset time, and the fourth preset time can be set according to actual conditions. For example, the first preset temperature can be set to 5°C, and the second preset temperature can be set to 65°C. The first preset time can be set to 5 minutes, and the second preset time, the third preset time, and the fourth preset time can all be set to 3 minutes.

[0034] In one embodiment, the initial target exhaust temperature is the target exhaust temperature of the outdoor unit 110 when the electronic expansion valve is opened at the initial opening degree. The calculation formula of the initial target exhaust temperature is:

[0035] represents the initial target exhaust temperature, represents the average value of the indoor coil temperature of each indoor unit 120 when the electronic expansion valve is opened at the initial opening degree, represents the desired temperature difference, which is used to set the desired temperature difference of the target exhaust temperature relative to the average value of the indoor coil temperature of each indoor unit 120. For example, It can be set to 11°C, that is, the initial target exhaust temperature must be set 11°C higher than the average indoor coil temperature to ensure that the system has a large enough temperature difference to drive heat exchange during initial operation, thereby improving response speed and stability. In another embodiment, when the one-to-many air conditioning system 100 meets a first preset condition, the target exhaust temperature of the outdoor unit 110 in cooling mode or heating mode is re-determined. In heating mode, a first target exhaust temperature of the outdoor unit 110 is calculated based on a first target exhaust temperature calculation formula, and the opening of each electronic expansion valve is adjusted based on the first target exhaust temperature. In cooling mode, a second target exhaust temperature of the outdoor unit 110 is calculated based on a second target exhaust temperature calculation formula, and the opening of each electronic expansion valve is adjusted based on the second target exhaust temperature.

[0036] In one embodiment, the first target exhaust temperature calculation formula is:

[0037] Indicates the first target exhaust temperature in heating mode. Indicates the frequency correlation coefficient in heating mode, Indicates the actual operating frequency of the compressor in the one-to-many air conditioning system 100 in heating mode. Indicates the indoor coil temperature correlation coefficient in heating mode, represents the average value of the indoor coil temperature of each indoor unit 120 in the heating mode, Indicates the ground source water outlet temperature of the one-to-many air conditioning system 100 in heating mode. A correction term that represents the actual operating frequency of the compressor.

[0038] In another embodiment, the second target exhaust temperature is calculated as follows:

[0039] Indicates the second target exhaust temperature in cooling mode. Indicates the frequency correlation coefficient in cooling mode, Indicates the actual operating frequency of the compressors in the one-to-many air conditioning system 100 in cooling mode. Indicates the correction term for the second target exhaust temperature in cooling mode, Indicates the ground source water outlet temperature of the one-to-many air conditioning system 100 in cooling mode.

[0040] In this embodiment, the frequency correlation coefficient is used to correlate the real-time target exhaust temperature with the real-time compressor operating frequency, and the setting range of the frequency correlation coefficient can be 0.1~0.9. The indoor coil temperature correlation coefficient in heating mode is used to correlate the real-time target exhaust temperature with the average value of the real-time indoor coil temperature, and the setting range of the indoor coil temperature correlation coefficient in heating mode is 0.1~0.9. The correction term for the second target exhaust temperature in cooling mode is used to compensate for the nonlinear error of the system, and the setting range of the correction term for the second target exhaust temperature in cooling mode is 0~40°C. The correction term for the actual operating frequency of the compressor is used to compensate for the target exhaust temperature at different compressor operating frequencies to optimize the system operating efficiency and stability. The correction term for the compressor's actual operating frequency is limited by the range of the compressor's actual operating frequency. When the correction term for the compressor's actual operating frequency is less than or equal to 30 Hz, the correction term can be set to 6°C. When the compressor's actual operating frequency is in the range of [30 Hz, 50 Hz], the correction term can be set to 3°C. When the compressor's actual operating frequency is greater than 50 Hz, the correction term can be set to 0°C. This target exhaust temperature calculation formula is used in the electronic expansion valve control phase following the initial adjustment phase. The target exhaust temperature is dynamically adjusted based on the current system state to ensure stable system operation and improve heating or cooling efficiency.

[0041] S230: Adjust the opening of each electronic expansion valve according to the target exhaust temperature to adjust the actual exhaust temperature of the outdoor unit 110 to near the target exhaust temperature.

[0042] In one embodiment, the present application calculates an exhaust temperature difference based on the current actual exhaust temperature and the target exhaust temperature, as well as the previous actual exhaust temperature and the target exhaust temperature. The exhaust temperature difference includes the difference between the current actual exhaust temperature of the outdoor unit 110 and the current target exhaust temperature, as well as the difference between the previous actual exhaust temperature and the previous target exhaust temperature. Based on the exhaust temperature difference, the current number of opening adjustment steps for the electronic expansion valve is calculated, and the opening of each electronic expansion valve is adjusted according to the current number of opening adjustment steps until the actual exhaust temperature of the outdoor unit 110 is adjusted to near the target exhaust temperature.

[0043] In one embodiment, the calculation formula for the number of opening adjustment steps of the electronic expansion valve at the current moment is:

[0044] Indicates the number of opening adjustment steps at the current moment, represents the proportional gain coefficient of the closed-loop control algorithm, Indicates the actual exhaust temperature at the current moment, Indicates the target exhaust temperature at the current moment, represents the differential gain of the closed-loop control algorithm, Indicates the actual exhaust temperature at the previous moment, Indicates the target exhaust temperature at the previous moment. The time interval between the current moment and the previous moment can be set according to actual conditions. For example, the time interval between the current moment and the previous moment can be 30 seconds.

[0045] This application uses a closed-loop PD (Proportional-Derivative) control algorithm to quickly respond to exhaust temperature differences, reduce overshoot, and avoid integral saturation. By adjusting the opening of the electronic expansion valve, this application brings the actual exhaust temperature close to the target exhaust temperature, ensuring safe compressor operation, improving system energy efficiency, and optimizing room temperature control efficiency.

[0046] In one embodiment, if Figure 3 As shown, the control method of the one-to-many air conditioning system 100 also includes: S240 , when the actual exhaust temperature of the outdoor unit 110 meets a second preset condition, the average value of the indoor coil temperatures of each indoor unit 120 is used as the target coil temperature; the second preset condition is a trigger basis for adjusting the indoor coil temperature of the indoor unit 120 .

[0047] In one embodiment, the second preset condition is that the difference between the actual exhaust temperature of the outdoor unit 110 and the target exhaust temperature is within a first preset range and persists for a fifth preset time. In this embodiment, the first preset range and the fifth preset time can be set according to actual conditions. For example, the first preset range can be [-2°C, +2°C], and the fifth preset time can be 3 minutes.

[0048] S250: Adjust the opening of each electronic expansion valve according to the target coil temperature to adjust the indoor coil temperature of each indoor unit 120 to be consistent.

[0049] In one embodiment, similar to the aforementioned method of adjusting the opening of each electronic expansion valve based on the target exhaust temperature, the present application can calculate a coil temperature difference based on the actual indoor coil temperature and the target coil temperature of each indoor unit 120 at the current moment, as well as the actual indoor coil temperature and the target coil temperature of each indoor unit 120 at the previous moment. The coil temperature difference includes the difference between the actual indoor coil temperature of each indoor unit 120 at the current moment and the target coil temperature at the current moment, as well as the difference between the actual indoor coil temperature of each indoor unit 120 at the previous moment and the target coil temperature at the previous moment. Based on the coil temperature difference, the current opening adjustment step number of the electronic expansion valve is calculated, and the opening of each electronic expansion valve is adjusted according to the current opening adjustment step number until the indoor coil temperatures of each indoor unit 120 are adjusted to be consistent.

[0050] For example, in one embodiment, taking the electronic expansion valve of one of the indoor units 120 as an example, the calculation formula for the number of opening adjustment steps of the electronic expansion valve of the indoor unit 120 at the current moment is:

[0051] Indicates the number of opening adjustment steps of the electronic expansion valve at the current moment when the indoor coil temperature is adjusted. Indicates the actual indoor coil temperature of the indoor unit 120 at the current moment, Indicates the target coil temperature at the current moment, Indicates the actual indoor coil temperature of the indoor unit 120 at the last moment, Indicates the target coil temperature at the previous moment.

[0052] In this embodiment, the application sets the average indoor coil temperature of each room as a unified target coil temperature. Each electronic expansion valve independently adjusts its opening based on the difference between the actual coil temperature of its corresponding room and the target coil temperature, ultimately making the coil temperatures in all rooms approach consistency, thereby achieving room temperature consistency control. This application uses the PD control algorithm to improve the adjustment accuracy of the electronic expansion valve, achieving rapid response, reducing oscillation, and improving control accuracy.

[0053] S260, when the actual exhaust temperature of the outdoor unit 110 meets the third preset condition, the opening of each electronic expansion valve is adjusted again according to the target exhaust temperature; the third preset condition is the trigger basis for exiting the adjustment of the indoor coil temperature of the indoor unit 120 and entering the adjustment of the actual exhaust temperature of the outdoor unit 110.

[0054] In one embodiment, the third preset condition may be that the difference between the actual exhaust temperature of the outdoor unit 110 and the target exhaust temperature is not within a second preset range. In this embodiment, the second preset range can be set according to actual conditions. For example, the second preset range may be [-4°C, +4°C].

[0055] It can be understood that in the initial stage of compressor startup, the present application only opens the electronic expansion valve for rooms with cooling / heating needs and sets it to the initial opening, thereby solving the problem of unstable control strategy in the initial stage of compressor startup. After stabilization, it switches to the control strategy based on the target exhaust temperature, controls the electronic expansion valve in each room to dynamically adjust the opening according to the target exhaust temperature, and makes the electronic expansion valves in each room respond synchronously, thereby avoiding control oscillation and inconsistent response caused by factors such as room heat load differences and unstable pressure differences, and improving cooling or heating efficiency. Under preset conditions, the opening of the electronic expansion valve is controlled according to the average internal coil temperature, so that the coil temperature in each room approaches consistency, avoiding poor effects in some rooms and overcooling or overheating in others, thereby improving overall comfort and energy efficiency.

[0056] In one embodiment, the present application also controls the operating frequency of the compressor in the one-to-many air conditioning system 100 based on the number of operating indoor units 120. In this embodiment, the operating frequency of the compressor can be increased when the number of operating indoor units 120 increases, and can be decreased when the number of operating indoor units 120 decreases. The amount of increase or decrease in the operating frequency of the compressor can be set according to actual conditions and is not limited here. For example, when only one room's indoor unit 120 is turned on, the operating frequency of the compressor is 35 Hz. If two rooms' indoor units 120 are turned on, the operating frequency of the compressor is 60 Hz. When three rooms' indoor units 120 are turned on, the operating frequency of the compressor is 80 Hz.

[0057] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can also be implemented in other ways. The device embodiments described above are merely schematic. For example, the flowcharts and structure diagrams in the accompanying drawings show the possible architectures, functions and operations of the devices, methods and computer program products according to the multiple embodiments of the present application. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of the code, and the module, program segment or a part of the code contains one or more executable instructions for implementing the specified logical functions. It should also be noted that in an alternative implementation, the functions marked in the box can also occur in an order different from that marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the structure diagram and / or flowchart, and the combination of boxes in the structure diagram and / or flowchart, can be implemented using a dedicated hardware-based system that performs the specified function or action, or can be implemented using a combination of dedicated hardware and computer instructions.

[0058] In addition, the functional modules or units in the various embodiments of the present application can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0059] If the functions are implemented in the form of software function modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes a number of instructions for enabling a computer device (which can be a smart phone, personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application.

[0060] The above is only a specific implementation method of the present application, but the scope of protection of the present application is not limited thereto. Any technician familiar with this technical field can easily think of changes or replacements within the technical scope disclosed in this application, which should be covered by the scope of protection of the present application.

Claims

1. A control method for a one-to-many air conditioning system, characterized in that: The one-to-many air conditioning system includes an outdoor unit and multiple indoor units, and the control method includes: When the plurality of indoor units of the one-to-many air-conditioning system are simultaneously turned on in cooling mode or heating mode, controlling the electronic expansion valve of each indoor unit to open at an initial opening; When the one-to-many air conditioning system satisfies a first preset condition, calculating a target exhaust temperature of the outdoor unit in the cooling mode or the heating mode; wherein the first preset condition is a trigger basis for adjusting the actual exhaust temperature of the outdoor unit; The opening of each electronic expansion valve is adjusted according to the target exhaust temperature to adjust the actual exhaust temperature of the outdoor unit to be close to the target exhaust temperature.

2. The control method of a one-to-many air conditioning system according to claim 1, characterized in that: Also includes: When the actual exhaust temperature of the outdoor unit meets a second preset condition, taking the average of the indoor coil temperatures of each of the indoor units as the target coil temperature; The second preset condition is a trigger basis for adjusting the indoor coil temperature of the indoor unit; adjusting the opening of each electronic expansion valve according to the target coil temperature to adjust the indoor coil temperature of each indoor unit to be consistent; When the actual exhaust temperature of the outdoor unit meets a third preset condition, adjusting the opening of each electronic expansion valve again according to the target exhaust temperature; The third preset condition is a triggering basis for exiting the adjustment of the indoor coil temperature of the indoor unit and entering the adjustment of the actual exhaust temperature of the outdoor unit.

3. The control method of a one-to-many air conditioning system according to claim 1, characterized in that: The calculating the target exhaust temperature of the outdoor unit in the cooling mode or the heating mode includes: Under the heating mode, calculating a first target exhaust temperature of the outdoor unit based on a first target exhaust temperature calculation formula, so as to adjust the opening of each electronic expansion valve according to the first target exhaust temperature; Under the cooling mode, a second target exhaust temperature of the outdoor unit is calculated based on a second target exhaust temperature calculation formula, so as to adjust the opening of each electronic expansion valve according to the second target exhaust temperature.

4. The control method of a one-to-many air conditioning system according to claim 1, characterized in that: The first preset condition is: The initial opening time of the electronic expansion valve is equal to the first preset time; Alternatively, in the heating mode, the actual exhaust temperature of the outdoor unit is greater than or equal to the initial target exhaust temperature and lasts for a second preset time; Alternatively, in the cooling mode, the return air superheat is greater than or equal to the first preset temperature and lasts for a third preset time, and the actual exhaust temperature of the outdoor unit is greater than or equal to the second preset temperature and lasts for a fourth preset time; wherein the return air superheat is the difference between the refrigerant gas temperature of the compressor entering the one-to-many air-conditioning system and the average value of the indoor coil temperature of each of the indoor units.

5. The control method of a one-to-many air conditioning system according to claim 1, characterized in that: The adjusting the opening of each electronic expansion valve according to the target exhaust temperature includes: Calculating an exhaust temperature difference, the exhaust temperature difference including a difference between an actual exhaust temperature of the outdoor unit at a current moment and a target exhaust temperature at a current moment, and a difference between an actual exhaust temperature at a previous moment and a target exhaust temperature at a previous moment; The number of opening adjustment steps of the electronic expansion valve at the current moment is calculated based on the exhaust temperature difference, so as to adjust the opening of each electronic expansion valve according to the number of opening adjustment steps at the current moment until the actual exhaust temperature of the outdoor unit is adjusted to near the target exhaust temperature.

6. The control method of a one-to-many air conditioning system according to claim 2, characterized in that: The second preset condition is: the difference between the actual exhaust temperature of the outdoor unit and the target exhaust temperature is within a first preset range and lasts for a fifth preset time; The third preset condition is that the difference between the actual exhaust temperature of the outdoor unit and the target exhaust temperature is not within a second preset range.

7. The control method of a one-to-many air conditioning system according to claim 3, characterized in that: The calculation formula of the first target exhaust temperature is: represents the first target exhaust temperature in the heating mode, represents the frequency correlation coefficient in the heating mode, Indicates the actual operating frequency of the compressor in the one-to-many air-conditioning system in the heating mode, represents the indoor coil temperature correlation coefficient in the heating mode, represents the average value of the indoor coil temperature of each of the indoor units in the heating mode, Indicates the ground source water outlet temperature of the one-to-many air conditioning system in the heating mode, A correction term representing the actual operating frequency of the compressor; The calculation formula for the second target exhaust temperature is: represents the second target exhaust temperature in the cooling mode, represents the frequency correlation coefficient during the cooling mode, Indicates the actual operating frequency of the compressor in the one-to-many air-conditioning system in the cooling mode, represents a correction term for the second target exhaust temperature in the cooling mode, Indicates the ground source water outlet temperature of the one-to-many air conditioning system in the cooling mode.

8. The control method of a one-to-many air conditioning system according to claim 5, characterized in that: The calculation formula for the number of opening adjustment steps of the electronic expansion valve at the current moment is: Indicates the number of opening adjustment steps at the current moment, represents the proportional gain coefficient of the closed-loop control algorithm, represents the actual exhaust temperature at the current moment, represents the target exhaust temperature at the current moment, represents the differential gain of the closed-loop control algorithm, Indicates the actual exhaust temperature at the previous moment, Indicates the target exhaust temperature at the previous moment.

9. The control method of a one-to-many air conditioning system according to claim 1, characterized in that: Also includes: The operating frequency of the compressor in the one-to-many air-conditioning system is controlled according to the operating number of the indoor units, wherein the operating frequency of the compressor is increased when the operating number of the indoor units increases, and the operating frequency of the compressor is reduced when the operating number of the indoor units decreases.

10. A one-to-many air conditioning system, characterized in that: The one-to-many air-conditioning system comprises an outdoor unit and multiple indoor units, and is used to execute the control method of the one-to-many air-conditioning system as described in any one of claims 1-9.

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