Control method and system of multi-split air conditioning system

Abstract

The invention discloses a control method and system of a multi-split air conditioning system, the multi-split air conditioning system comprises at least two outdoor units, and the multi-split air conditioning system has a heating mode; the control method is used for a heating mode and comprises the steps that loading or unloading of each outdoor unit is controlled based on a preset target condensation temperature; low-pressure values of the low-pressure sides of all the outdoor units are monitored, and the average value of the low-pressure values of all the outdoor units is calculated; for any outdoor unit, the difference value between the low-pressure value of the outdoor unit and the average low-pressure value is calculated, so that a low-pressure deviation value corresponding to the outdoor unit is obtained; the preset target condensation temperature is corrected based on the low-pressure deviation value corresponding to each outdoor unit, so that the corrected target condensation temperature corresponding to each outdoor unit at present is obtained; and loading or unloading of the corresponding outdoor unit is controlled based on the corrected target condensation temperature. Based on the control method, the stability of the multi-split air conditioning system is improved, the overall energy efficiency of the system is further optimized, and the use experience of a user is more stable and comfortable.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioning system control, and in particular to a control method and system for a multi-split air conditioning system. Background Art

[0002] A multi-split air conditioning system is a single refrigeration cycle system consisting of one or more air-cooled outdoor units connected to one or more direct evaporative indoor units of different or the same type and capacity. This system can directly provide processed air to one or more areas, achieving centralized control and zoning management. Multi-split air conditioning systems have been widely used in commercial and residential buildings due to their high efficiency, energy saving, and flexibility.

[0003] At present, in the heating mode, the control strategy for the outdoor unit of the multi-split air conditioning system generally adopts the method of setting a unified target condensing temperature. Specifically, the control system will preset a target value for the condensing temperature, and then dynamically adjust the operating state of the compressor based on the comparison result between the current condensing temperature of each outdoor unit and the target value of the condensing temperature: if the current condensing temperature is lower than the target value, the outdoor unit is instructed to increase the load to improve the heating efficiency; otherwise, the load is reduced to avoid overheating.

[0004] However, this control strategy is prone to instability in the control process when faced with uneven cooling capacity of outdoor units in the air-conditioning system or defects in system installation. Specifically, due to differences in performance of each outdoor unit, if the outdoor unit is simply controlled to condense at the same target condensing temperature, the operating process parameters of the outdoor unit will be different and may deviate from the preset safe operating range, thereby triggering fault alarms such as high pressure protection, low pressure protection and high exhaust temperature. Such unstable conditions will not only damage the overall stability and energy efficiency performance of the air-conditioning system, but also affect the customer's experience. Summary of the invention

[0005] The object of the present invention is to provide a control method and system for a multi-split air-conditioning system, which can correct the target condensing temperature of an outdoor unit to enhance the control stability and operation efficiency of the multi-split air-conditioning system.

[0006] To achieve the above object, the present invention discloses a multi-split air conditioning system, the multi-split air conditioning system comprises at least two external units, and the multi-split air conditioning system comprises a heating mode;

[0007] The present invention also discloses a control method for the multi-split air conditioning system, the control method is used in a heating mode, and the control method includes:

[0008] Controlling the loading or unloading of each of the outdoor units based on a preset target condensing temperature;

[0009] Monitoring the low pressure values ​​of the low pressure sides of all the external units, and calculating the average value of the low pressure values ​​of all the external units to obtain an average low pressure value;

[0010] For any of the external units, calculating the difference between the low pressure value of the external unit and the average low pressure value to obtain a low pressure deviation value corresponding to the external unit;

[0011] Correcting the preset target condensing temperature based on the low pressure deviation value corresponding to each of the outdoor units to obtain a corrected target condensing temperature corresponding to each of the current outdoor units;

[0012] The loading or unloading of the corresponding outdoor unit is controlled based on the corrected target condensing temperature.

[0013] Specifically, the low pressure deviation value LS_cu is calculated based on the following formula: n ;

[0014] LS_cu n =LS n -LS_aver

[0015] Wherein, n represents the serial number of each of the external units, LS_cu n Indicates the low voltage deviation value corresponding to the nth external unit, LS n represents the low pressure value corresponding to the nth external unit, and LS_aver represents the average low pressure value.

[0016] Specifically, the calculation method of the modified target condensing temperature includes:

[0017] When the low pressure deviation value corresponding to the outdoor unit is greater than or equal to a preset first threshold value, the corrected target condensing temperature of the outdoor unit is the difference between the target condensing temperature and a preset correction value;

[0018] When the low pressure deviation value corresponding to the outdoor unit is less than the first threshold value and greater than a preset second threshold value, the modified target condensing temperature of the outdoor unit is the target condensing temperature;

[0019] When the low pressure deviation value corresponding to the outdoor unit is less than or equal to the second threshold value, the corrected target condensing temperature of the outdoor unit is the sum of the target condensing temperature and the correction value.

[0020] Specifically, the method for controlling the loading or unloading of the corresponding outdoor unit based on the modified target condensing temperature includes:

[0021] Obtaining the current energy demand value of each of the outdoor units and the corresponding condensing temperature;

[0022] Calculating the average value of the current condensing temperatures of all the outdoor units to obtain an average condensing temperature;

[0023] Calculating the difference between the modified target condensing temperature corresponding to each of the outdoor units and the average condensing temperature to obtain a modified judgment value corresponding to each of the outdoor units;

[0024] The energy demand value of each of the external machines is corrected based on the correction judgment value corresponding to each of the external machines and the current energy demand value.

[0025] Furthermore, the control method further comprises:

[0026] When the absolute value of the modified judgment value is less than or equal to a preset third threshold value, maintaining the current energy demand value of the outdoor unit unchanged;

[0027] When the absolute value of the corrected judgment value is greater than the third threshold value, the energy requirement deviation value is calculated based on the corrected judgment value corresponding to each of the external units, and based on the energy requirement deviation value and the current energy requirement value, the corrected energy requirement value required by each of the external units is calculated to obtain the corrected energy requirement value corresponding to each of the external units.

[0028] Furthermore, when the absolute value of the modified judgment value is greater than the third threshold value, it is also necessary to determine whether the modified judgment value is a positive value. If so, the modified energy demand value of the external unit is the sum of the current energy demand value and the energy demand deviation value. If not, the modified energy demand value of the external unit is the difference between the current energy demand value and the energy demand deviation value.

[0029] Furthermore, it also includes an energy demand correction cycle. Every time each of the outdoor units runs through the energy demand correction cycle, the current energy demand value of each of the outdoor units is corrected again.

[0030] The present invention further discloses a multi-split air conditioning system, which includes a control system, and the control system works based on the control method as described above.

[0031] The present invention also discloses a control system for a multi-connected air conditioning system, which comprises:

[0032] one or more processors;

[0033] Memory;

[0034] and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the programs including instructions for executing the control method as described above.

[0035] The present invention also discloses a computer-readable storage medium, which includes a computer program. The computer program can be executed by a processor to implement the control method as described above.

[0036] Compared with the prior art, the control method provided by the above technical solution of the present invention further refines the strategy of adding and reducing loads of the external units by introducing the overall average low pressure value of the external units as a key condition. The control method provided by the present invention first monitors the low pressure value of each external unit in the system, and then corrects the target condensing temperature of each external unit according to the actual situation of the low pressure value of each external unit, and then guides each external unit to adjust the load appropriately according to the target condensing temperature. In this process, the operating states of the external units dynamically influence each other, and a relative balance is achieved between the capacity distribution. This control method not only improves the stability of the multi-split air-conditioning system, but also significantly improves the overall energy efficiency of the system by optimizing the load distribution, thereby providing users with a more continuous, efficient and comfortable use experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 The figure is a flow chart of a control method according to an embodiment of the present invention.

[0038] Figure 2 The figure is a flow chart of a method for controlling loading or unloading of an external machine in an embodiment of the present invention.

[0039] Figure 3 This is a flow chart of a method for controlling loading or unloading of an external machine in another embodiment of the present invention. DETAILED DESCRIPTION

[0040] In order to explain the technical content, structural features, achieved objectives and effects of the present invention in detail, the following is a detailed description in conjunction with the implementation methods and the accompanying drawings.

[0041] This embodiment discloses a multi-split air-conditioning system, which includes at least two external units and a heating mode.

[0042] Based on the multi-split air-conditioning system of this structure, the present embodiment discloses a control method and system for the multi-split air-conditioning system to enhance the control stability and operation efficiency of the multi-split air-conditioning system, thereby improving the stability and overall energy efficiency of the multi-split air-conditioning system, and bringing users a more continuous, efficient and comfortable use experience.

[0043] See also Figure 1 As shown, the control method of this embodiment specifically includes the following steps:

[0044] S11: Controlling the loading or unloading of each outdoor unit based on a preset target condensing temperature.

[0045] S12: Monitor the low-pressure values on the low-pressure sides of all outdoor units, and calculate the average value of the low-pressure values of all outdoor units to obtain the average low-pressure value.

[0046] S13: Calculate the difference between the low-pressure value corresponding to each outdoor unit and the average low-pressure value to obtain the low-pressure deviation value corresponding to each outdoor unit.

[0047] S14: Modify the preset target condensation temperature based on the low-pressure deviation value corresponding to each outdoor unit to obtain the modified target condensation temperature corresponding to each current outdoor unit.

[0048] S15: Control the loading or unloading of the corresponding outdoor unit based on the modified target condensation temperature.

[0049] Specifically, calculate the low-pressure deviation value of each outdoor unit based on the following formula:

[0050] LS_cu n = LS n - LS_aver

[0051] where n represents the serial number of each outdoor unit, LS_cu n represents the low-pressure deviation value corresponding to the nth outdoor unit, LS n represents the low-pressure value corresponding to the nth outdoor unit, and LS_aver represents the average low-pressure value.

[0052] Specifically, assume the target condensation temperature is T p , the modified target condensation temperature is T sn , n represents the serial number of each outdoor unit, a and b are respectively the preset first threshold and second threshold related to the low-pressure deviation value LS_cu n , the preset correction value of the modified target condensation temperature is T1, and the calculation method of the modified target condensation temperature T sn includes:

[0053] When the low-pressure deviation value corresponding to the outdoor unit is greater than or equal to the preset first threshold, the modified target condensation temperature of the outdoor unit is the difference between the target condensation temperature and the preset correction value, that is, when LS_cu n ≥ a, T sn = T p - T1;

[0054] When the low-pressure deviation value corresponding to the outdoor unit is less than the first threshold and greater than the preset second threshold, the modified target condensation temperature of the outdoor unit is the target condensation temperature, that is, when b < LS_cu n < a, T sn = T p ;

[0055] When the low pressure deviation value corresponding to the outdoor unit is less than or equal to the second threshold, the corrected target condensing temperature of the outdoor unit is the sum of the target condensing temperature and the correction value, that is, when LS_cu n When ≤b, T sn =T p -T1.

[0056] Among them, the target condensation temperature T p The value range of is 35-55℃, and the preferred value is 48℃; the preferred value of a is 1, the preferred value of b is -1, and the preferred value of T1 is 2.

[0057] On the other hand, see Figure 2 As shown, the corrected target condensation temperature T sn Methods for controlling the loading or unloading of the corresponding external machine include:

[0058] S21: Obtain the current energy demand value E of each external unit n And the corresponding condensation temperature T;

[0059] S22: Calculate the average value of the condensing temperature T of all the current outdoor units to obtain the average condensing temperature T_aver n ;

[0060] S23: Calculate the corrected target condensing temperature T corresponding to each outdoor unit sn and the average condensation temperature T_aver n The difference between the values ​​of n ;

[0061] S24: Correction judgment value q corresponding to each external unit n and the current energy demand value E n , the energy demand value E of each external unit n Make corrections.

[0062] For further information, see Figure 3 As shown, a preset third threshold c related to the modified judgment value is also included, and step S24 further includes:

[0063] S241: Determine the absolute value of the corrected judgment value |q n |Is it less than or equal to the third threshold c? If so, jump to step S242; if not, jump to step S243.

[0064] S242: Maintain the current energy demand value E of the external unit n constant.

[0065] S243: Correction judgment value q based on each external unit n Calculation requires deviation value K n , and based on the energy demand deviation value Kn and the current energy demand value E n , calculate the corrected energy demand value of each external unit to obtain the corrected energy demand value E corresponding to each external unit n ′.

[0066] The value range of the third threshold c is [0.2, 4.0], and the preferred value is 1.5.

[0067] Furthermore, when |q n |>c, the corrected judgment value q is determined n Is it a positive value? If so, the correction energy required for the external unit is E n ′ is the current energy demand value E n Deviation value K from energy requirement n The sum of E n ′=E n +K n If not, the correction value of the external unit is E n ′ is the current energy demand value E n Deviation value K from energy requirement n The difference, that is, E n ′=E n -K n .

[0068] Specifically, it is also necessary to monitor the high pressure value HS on the high pressure side of the multi-split air conditioning system n To determine the required deviation value K n . The required deviation value K n The determination is shown in Table 1 below:

[0069] Table 1 Energy required deviation value K n surface

[0070]

[0071]

[0072] For example, assuming that the rated capacity of the outdoor unit 1 is 7HP, the currently detected corrected judgment value q1 of the outdoor unit 1 is -11°C, and the high pressure value HS1 on the high pressure side is 36bar. At this time, the corrected judgment value q1 is less than -10 and the high pressure value HS1 is greater than 35bar. According to Table 1, the energy demand deviation value K1 of the outdoor unit can be obtained as 7 / 10E1.

[0073] It should be noted that the rated capacity of the external units on the market is mostly produced in increments of 2HP. If the rated capacity of the external unit actually used is not within the range included in Table 1, the optimal energy demand deviation value is calculated and selected based on the actual rated capacity of the external unit. Based on the optimal energy demand deviation value, the control method of this embodiment is applied to correct the energy demand value E. n ' is calculated. Take the following embodiment as an example:

[0074] Assume that the rated capacity of outdoor unit 1 is 7HP, the current energy demand of outdoor unit 1 is 4HP, and the corrected condensing temperature T of outdoor unit 1 is s1 The difference q1 with the average condensing temperature T_aver1 is -2, and the corrected judgment value q1=-2, which is a non-positive negative number. From Table 1, it can be obtained that the energy demand deviation value K1 is 1, and the corrected energy demand value E1′ is the difference between the current energy demand value E1 and the energy demand deviation value K1, that is, E1′=E1-K1=7-1=6HP.

[0075] Furthermore, this embodiment also includes an energy demand correction cycle. Each time each outdoor unit runs an energy demand correction cycle, the current energy demand value of each outdoor unit is corrected again. Correcting the current energy demand value multiple times is conducive to better distributing the load inside the multi-split system, so that the operation of the outdoor unit can meet the user's cooling temperature demand more quickly. The preferred value of the correction cycle is 32s.

[0076] In another preferred embodiment of the present invention, a multi-split air conditioning system is disclosed, which includes a control system, and the control system works based on the above control method.

[0077] The present invention also discloses a control system for a multi-split air conditioning system, which includes one or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and are configured to be executed by the one or more processors, and the program includes instructions for executing the control method as described above. The processor can be a general-purpose central processing unit (CPU), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits for executing related programs to execute the control method of the method embodiment of the present application.

[0078] The present invention also discloses a computer-readable storage medium, which includes a computer program, and the computer program can be executed by a processor to complete the control method as described above. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server or a data center that includes one or more available media integrated. The available medium can be a read-only memory (ROM), or a random access memory (RAM), or a magnetic medium, such as a floppy disk, a hard disk, a tape, a magnetic disk, or an optical medium, such as a digital versatile disc (DVD), or a semiconductor medium, such as a solid state disk (SSD).

[0079] The embodiment of the present application also discloses a computer program product or a computer program, which includes a computer instruction stored in a computer-readable storage medium. A processor of an electronic device reads the computer instruction from the computer-readable storage medium, and the processor executes the computer instruction, so that the electronic device executes the above control method.

[0080] The above disclosure is only the preferred embodiment of the present invention, which certainly cannot be used to limit the scope of rights of the present invention. Therefore, equivalent changes made according to the scope of the patent application of the present invention are still within the scope covered by the present invention.

Claims

1. A control method for a multi-split air conditioning system, characterized in that: The multi-split air conditioning system includes at least two external units, and the multi-split air conditioning system includes a heating mode; the control method is used in the heating mode, and the control method includes: Controlling the loading or unloading of each of the outdoor units based on a preset target condensing temperature; Monitoring the low pressure values ​​of the low pressure sides of all the external units, and calculating the average value of the low pressure values ​​of all the external units to obtain an average low pressure value; For any of the external units, calculating the difference between the low pressure value of the external unit and the average low pressure value to obtain a low pressure deviation value corresponding to the external unit; Correcting the preset target condensing temperature based on the low pressure deviation value corresponding to each of the outdoor units to obtain a corrected target condensing temperature corresponding to each of the current outdoor units; The loading or unloading of the corresponding outdoor unit is controlled based on the corrected target condensing temperature.

2. The control method of the multi-split air conditioning system according to claim 1, characterized in that: The low pressure deviation value LS_cu is calculated based on the following formula n ; LS_cu n =LS n -LS_other Wherein, n represents the serial number of each of the external units, LS_cu n Indicates the low voltage deviation value corresponding to the nth external unit, LS n represents the low pressure value corresponding to the nth external unit, and LS_aver represents the average low pressure value.

3. The control method of a multi-split air conditioning system according to claim 1, characterized in that: The calculation method of the modified target condensing temperature includes: When the low pressure deviation value corresponding to the outdoor unit is greater than or equal to a preset first threshold value, the corrected target condensing temperature of the outdoor unit is the difference between the target condensing temperature and a preset correction value; When the low pressure deviation value corresponding to the outdoor unit is less than the first threshold value and greater than a preset second threshold value, the modified target condensing temperature of the outdoor unit is the target condensing temperature; When the low pressure deviation value corresponding to the outdoor unit is less than or equal to the second threshold value, the corrected target condensing temperature of the outdoor unit is the sum of the target condensing temperature and the correction value.

4. The control method of a multi-split air conditioning system according to claim 1, characterized in that: The method for controlling the loading or unloading of the corresponding external machine based on the modified target condensing temperature includes: Obtaining the current energy demand value of each of the outdoor units and the corresponding condensing temperature; Calculating the average value of the current condensing temperatures of all the outdoor units to obtain an average condensing temperature; Calculating the difference between the modified target condensing temperature corresponding to each of the outdoor units and the average condensing temperature to obtain a modified judgment value corresponding to each of the outdoor units; The energy demand value of each of the external machines is corrected based on the correction judgment value corresponding to each of the external machines and the current energy demand value.

5. The control method of the multi-split air conditioning system according to claim 4, characterized in that: When the absolute value of the modified judgment value is less than or equal to a preset third threshold value, maintaining the current energy demand value of the outdoor unit unchanged; When the absolute value of the corrected judgment value is greater than the third threshold value, the energy requirement deviation value is calculated based on the corrected judgment value corresponding to each of the external units, and based on the energy requirement deviation value and the current energy requirement value, the corrected energy requirement value required by each of the external units is calculated to obtain the corrected energy requirement value corresponding to each of the external units.

6. The control method of the multi-split air conditioning system according to claim 5, characterized in that: When the absolute value of the modified judgment value is greater than the third threshold value, it is also necessary to determine whether the modified judgment value is a positive value. If so, the modified energy demand value of the external unit is the sum of the current energy demand value and the energy demand deviation value. If not, the modified energy demand value of the external unit is the difference between the current energy demand value and the energy demand deviation value.

7. The control method of a multi-split air conditioning system according to claim 6, characterized in that: It also includes an energy demand correction cycle. Every time each of the external machines runs through the energy demand correction cycle, the current energy demand value of each of the external machines is corrected again.

8. A multi-split air conditioning system, characterized in that: The multi-split air conditioning system includes a control system, and the control system operates based on the control method according to any one of claims 1 to 7.

9. A control system for a multi-split air conditioning system, characterized in that: include: one or more processors; Memory; and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the programs comprising instructions for executing the control method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: The invention comprises a computer program which can be executed by a processor to implement the control method according to any one of claims 1 to 7.

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