Multi-link control method, multi-link and storage medium

Abstract

The present invention provides a multi-split control method, a multi-split and a storage medium. The multi-split control method includes: determining the operation mode of the multi-split; controlling the operation state of the multi-split according to the operation mode of the multi-split; when the operation mode of the multi-split is a high-capacity ratio heating and low-load operation mode, controlling the working indoor unit to operate normally; controlling the shutdown indoor unit to switch to cooling shutdown, shutting down the shutdown indoor unit and the corresponding throttling device, and connecting the shutdown indoor unit to a gas-liquid separator. According to the multi-split control method of the present invention, the risk of compressor oil shortage can be reduced and the system energy efficiency can be improved.

Description

Technical Field

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

[0002] When the heat recovery system is in heating operation, the indoor units without capacity demand will be shut down for heating by default, and the electronic expansion valve of the indoor unit will open a smaller opening to recover the refrigerant and refrigeration oil stored in the indoor unit heat exchanger to the system. However, when the heat recovery system has a high capacity ratio, if only a small number of indoor units have heating capacity demand, due to the excessive number of indoor units shut down for heating, a large amount of refrigerant and refrigeration oil will be stored in the indoor unit heat exchanger, causing the compressor to face the risk of oil shortage.

[0003] When the above-mentioned high-capacity ratio heat recovery multi-split heating machine is operating at low load, a large portion of the high-temperature and high-pressure gaseous refrigerant will bypass these stopped indoor units, resulting in a reduction in the refrigerant flow to the indoor units that need heating, causing insufficient heating capacity in the room and reducing user comfort. To ensure that the system's heating capacity meets user requirements, the compressor will increase its frequency, greatly reducing the system's energy efficiency. Summary of the invention

[0004] The main purpose of the present invention is to provide a multi-split control method, a multi-split and a storage medium, which can reduce the risk of compressor oil shortage and improve system energy efficiency.

[0005] In order to achieve the above object, according to one aspect of the present invention, a multi-link control method is provided, comprising:

[0006] Determine the operation mode of the multi-link;

[0007] Controlling the operating state of the multi-link according to the operating mode of the multi-link;

[0008] When the multi-split operation mode is high capacity ratio heating and low load operation mode,

[0009] Control the normal operation of the indoor unit;

[0010] The shutdown indoor unit is controlled to switch to cooling shutdown, the shutdown indoor unit and the corresponding throttling device are turned off, and the shutdown indoor unit is connected to the gas-liquid separator.

[0011] Furthermore, the step of determining the operation mode of the multi-link system includes:

[0012] Obtain the total capacity A of the indoor unit and the total capacity B of the outdoor unit;

[0013] When A / B≥C, the multi-link system is judged to be a high-capacity ratio heat recovery multi-link system;

[0014] When A / B<C, the VRF is judged to be a conventional capacity ratio heat recovery VRF, where C≥110%;

[0015] Get the total capacity D of the indoor units in heating mode.

[0016] When D / B≤E, it is judged that the heat recovery multi-connected mechanism is operating at low load;

[0017] When D / B>E, it is judged that the heat recovery multi-unit heating machine is operating at medium to high load, wherein E≤40%.

[0018] Furthermore, the step of controlling the operating state of the multi-split system according to the operating mode of the multi-split system further includes:

[0019] When A / B<C, the working room mechanism is controlled to start heating, and the shutdown room mechanism is controlled to stop heating.

[0020] Furthermore, the step of controlling the operating state of the multi-split system according to the operating mode of the multi-split system further includes:

[0021] When A / B≥C and D / B>E, the working room mechanism is controlled to start heating, and the shutdown room mechanism is controlled to stop heating.

[0022] Furthermore, when A / B≥C and D / B≤E, it is determined that the operation mode of the multi-split system is a high capacity ratio heating and low load operation mode.

[0023] Further, the steps of controlling the shutdown indoor unit to switch to cooling shutdown, closing the shutdown indoor unit and the corresponding throttling device, and connecting the shutdown indoor unit with the gas-liquid separator include:

[0024] Close the solenoid valve on the gas pipe at the inlet end and the throttling device at the outlet end of the stopped indoor unit;

[0025] The solenoid valve on the bypass pipeline connected to the air intake of the compressor is opened, so that the stopped indoor unit is connected to the gas-liquid separator through the bypass pipeline.

[0026] Furthermore, before the step of controlling the shutdown indoor unit to switch to cooling shutdown, the step also includes:

[0027] Get the information of the stopped indoor unit;

[0028] Determine whether the stopped indoor unit is a VIP indoor unit;

[0029] The steps of controlling the shutdown indoor unit to switch to cooling shutdown include:

[0030] When the stopped indoor unit is a VIP indoor unit, the VIP indoor unit is controlled to switch to heating shutdown, and other stopped indoor units are switched to cooling shutdown.

[0031] Furthermore, before the step of controlling the operating state of the multi-split system according to the operating mode of the multi-split system, the step further includes:

[0032] Set up VIP indoor unit.

[0033] Furthermore, the steps of setting the VIP indoor station include:

[0034] Receive VIP indoor unit request information;

[0035] When the VIP indoor unit request information is obtained, the target indoor unit is determined according to the request information;

[0036] Set the target indoor unit as the VIP indoor unit.

[0037] Further, C=135%, E=30%.

[0038] According to another aspect of the present invention, a multi-link system is provided, to which the multi-link system control method described above is applied.

[0039] According to another aspect of the present invention, a storage medium is provided, which is applied to the above-mentioned multi-connection control method.

[0040] Applying the technical solution of the present invention, the multi-split control method includes: judging the operation mode of the multi-split unit; controlling the operation state of the multi-split unit according to the operation mode of the multi-split unit; when the operation mode of the multi-split unit is a high-capacity ratio heating and low-load operation mode, controlling the working indoor unit to operate normally; controlling the shutdown indoor unit to switch to cooling shutdown, shutting down the shutdown indoor unit and the corresponding throttling device, and connecting the shutdown indoor unit to the gas-liquid separator. When the multi-connection operation mode is the high-capacity ratio heating and low-load operation mode, the multi-split control method switches the stopped indoor unit to cooling shutdown instead of the conventional heating shutdown, so that the electronic expansion valve corresponding to the stopped indoor unit can be closed, so that the refrigerant and refrigeration oil no longer flow into the stopped indoor unit, thereby ensuring that the system has sufficient refrigerant oil and reducing the risk of oil shortage in the compressor. In addition, since the electronic expansion valve of the stopped indoor unit is closed, the high-temperature and high-pressure gaseous refrigerant in the system will all flow into the indoor unit in heating operation, thereby increasing the refrigerant flow rate of the working indoor unit in heating operation, increasing the heat generation of the working indoor unit, and improving the comfort. At the same time, the energy efficiency of the system is improved, which is more energy-saving. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0042] Figure 1 A control flow chart of a multi-connection control method according to an embodiment of the present invention is shown;

[0043] Figure 2 A VIP indoor unit control flow chart of a multi-connected control method according to an embodiment of the present invention is shown;

[0044] Figure 3 A control system diagram showing a multi-split unit in a conventional capacity ratio state according to an embodiment of the present invention; and

[0045] Figure 4 A control system diagram of the multi-split unit according to an embodiment of the present invention is shown when it is in a high capacity ratio heating and high load operation mode.

[0046] The above drawings include the following reference numerals:

[0047] 1. Enthalpy spray electronic expansion valve; 2. Compressor; 3. Oil separator; 4. First one-way valve; 5. First four-way valve; 6. Second one-way valve; 7. Second four-way valve; 8. Outdoor unit heat exchanger; 9. Fan; 10. Heating electronic expansion valve; 11. Radiator; 12. Subcooler; 13. Subcooling electronic expansion valve; 14. First mode converter; 15. First solenoid valve; 16. Second solenoid valve; 17. First electronic expansion valve; 18. First indoor unit; 19. First indoor unit heat exchanger; 20. First 2. Second electronic expansion valve; 21. Second indoor unit; 22. Third solenoid valve; 23. Fourth solenoid valve; 24. Second mode converter; 25. Second indoor unit heat exchanger; 26. Third electronic expansion valve; 27. Third indoor unit; 28. Third indoor unit heat exchanger; 29. ​​Fifth solenoid valve; 30. Sixth solenoid valve; 31. Third mode converter; 32. High-pressure gas pipe stop valve; 33. Low-pressure gas pipe stop valve; 34. High-pressure liquid pipe stop valve; 35. Gas-liquid separator; 36. Subcooler solenoid valve. DETAILED DESCRIPTION

[0048] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0049] See also Figures 1 to 4 As shown, according to an embodiment of the present invention, the multi-split control method includes: determining the operating mode of the multi-split unit; controlling the operating state of the multi-split unit according to the operating mode of the multi-split unit; when the operating mode of the multi-split unit is a high-capacity ratio heating and low-load operating mode, controlling the working indoor unit to operate normally; controlling the shutdown indoor unit to switch to cooling shutdown, shutting down the shutdown indoor unit and the corresponding throttling device, and connecting the shutdown indoor unit to the gas-liquid separator.

[0050] When the multi-connection operation mode is the high-capacity ratio heating and low-load operation mode, the multi-split control method switches the stopped indoor unit to cooling shutdown instead of the conventional heating shutdown, so that the electronic expansion valve corresponding to the stopped indoor unit can be closed, so that the refrigerant and refrigerant oil no longer flow into the stopped indoor unit, preventing the refrigerant and refrigerant oil from being stored in the stopped indoor unit, thereby ensuring that the system has sufficient refrigerant oil and reducing the risk of oil shortage in the compressor. In addition, since the electronic expansion valve of the stopped indoor unit is closed, the high-temperature and high-pressure gaseous refrigerant in the system will all flow into the indoor unit in heating operation, thereby increasing the refrigerant flow rate of the working indoor unit in heating operation, increasing the heat generation of the working indoor unit, and improving the comfort. At the same time, the system energy efficiency is improved, which is more energy-saving.

[0051] In one embodiment, the step of determining the operating mode of the multi-split unit includes: obtaining the total capacity A of the indoor units and the total capacity B of the outdoor units; when A / B≥C, determining that the multi-split unit is a high-capacity ratio heat recovery multi-split unit; when A / B<C, determining that the multi-split unit is a conventional capacity ratio heat recovery multi-split unit, wherein C≥110%; obtaining the total capacity D of the indoor units in heating operation; when D / B≤E, determining that the heat recovery multi-split unit is operating at a low load; when D / B>E, determining that the heat recovery multi-split unit is operating at a medium to high load, wherein E≤40%.

[0052] In this embodiment, the operation modes of the multi-split system are divided, and the high-capacity ratio heat recovery multi-split system and the conventional capacity ratio heat recovery multi-split system are distinguished according to the ratio relationship between the total capacity A of the indoor unit and the total capacity B of the outdoor unit. The high-capacity ratio heat recovery multi-split system and the conventional capacity ratio heat recovery multi-split system can be accurately defined, thereby providing an accurate control basis for the control of the multi-split system, ensuring that the control of the multi-split system is more accurate and the control efficiency is higher. In addition, this embodiment also uses the ratio relationship between the total capacity D of the indoor unit and the total capacity B of the outdoor unit during the heating start-up operation as a basis for judging whether the multi-split system is in high-load operation, thereby accurately defining the compliance state of the multi-split system, and then accurately dividing the high-load operation state and low-load operation state of the multi-split system, and realizing accurate control of the multi-split system.

[0053] In one embodiment, C = 135%, E = 30%. C and E may also take other values, which may be specifically selected according to the model and parameters of the multi-link unit.

[0054] Through the above method, the operation mode of the multi-split system can be divided into four types. In the first operation mode, A / B≥C and D / B≤E, the multi-split operation mode is a high capacity ratio heating and low load operation mode; in the second operation mode, A / B≥C and D / B>E, the multi-split operation mode is a high capacity ratio heating and high load operation mode; in the third operation mode, A / B<C and D / B≤E, the multi-split operation mode is a conventional capacity ratio heating and low load operation mode; in the fourth operation mode, A / B<C and D / B>E, the multi-split operation mode is a conventional capacity ratio heating and high load operation mode.

[0055] The control method of the present invention performs control based on the above four modes to optimize the operation of the multi-split system.

[0056] In one embodiment, the step of controlling the operating state of the multi-split system according to the operating mode of the multi-split system further includes: when A / B<C, controlling the heating of the working chamber to start, and controlling the heating of the stopping chamber to stop.

[0057] When A / B<C, there are two cases. One is D / B≤E. At this time, the multi-split operation mode is the conventional capacity ratio heating low-load operation mode; the other is D / B>E. At this time, the multi-split operation mode is the conventional capacity ratio heating high-load operation mode. In these two operation modes, the control method of the multi-split is the same, which is to control the working room mechanism to start heating and control the shutdown room mechanism to stop heating.

[0058] In this case, since there is no high capacity ratio mode, a large amount of refrigerant and refrigerant oil will not be stored in the indoor unit heat exchanger due to too many indoor units being shut down for heating, which will cause the compressor to face the risk of oil shortage. Therefore, you only need to control the multi-split unit in the usual way.

[0059] In one embodiment, the step of controlling the operating state of the multi-split system according to the operating mode of the multi-split system further includes: when A / B≥C and D / B>E, controlling the working room mechanism to heat up and start, and controlling the stopping room mechanism to heat up and stop.

[0060] In this embodiment, when A / B≥C, and D / B>E, the multi-split operation mode is a high-capacity ratio heating high-load operation mode, so there are fewer indoor units that are shut down for heating. Since most of the indoor units are running, the refrigerant and refrigeration oil stored in the shut-down indoor units are also small, which will not affect the operation of the multi-split system. The simultaneous operation of most of the indoor units can also make the refrigeration oil in the system fully circulate, ensure that the system has enough refrigeration oil, and avoid the risk of compressor oil shortage. Since most of the indoor units are in operation, only a small part of the high-temperature and high-pressure gaseous refrigerant bypasses these shut-down indoor units, and the refrigerant flow in the indoor units that need heating will not be greatly reduced, which can ensure the refrigerant flow in the indoor units for heating. Therefore, the heating capacity of the indoor units for heating in the room can be sufficient to ensure the comfort of users.

[0061] In one embodiment, when A / B≥C and D / B≤E, it is determined that the operation mode of the multi-split system is a high capacity ratio heating and low load operation mode.

[0062] In this embodiment, since the operation mode of the multi-split unit is a high-capacity ratio heating and low-load operation mode, it is necessary to optimize the operation of the multi-split unit. By controlling the shutdown indoor unit to switch to a cooling shutdown mode, the path for the high-temperature and high-pressure refrigerant to accumulate in the shutdown indoor unit is cut off, so that the shutdown indoor unit is connected to the air inlet end of the gas-liquid separator through a bypass pipeline. In this way, the refrigerant pressure of the shutdown indoor unit can be relatively low, and a large amount of refrigerant and refrigerant oil will not be stored inside the shutdown indoor unit. Therefore, it can be ensured that the refrigerant oil fully participates in the system operation and that the refrigerant more fully participates in the system heat exchange. On the basis of ensuring that the compressor has sufficient refrigerant oil, it is ensured that there is sufficient refrigerant in the working indoor unit, so that the working indoor unit can provide sufficient heating capacity for the room, improve the user's comfort, and ensure that the system heating capacity meets user needs, so that the compressor does not need to be operated at a high frequency to meet the user's heating needs, thereby effectively improving the system energy efficiency.

[0063] In one embodiment, the steps of controlling the shutdown indoor unit to switch to refrigeration shutdown, closing the shutdown indoor unit and the corresponding throttling device, and connecting the shutdown indoor unit with the gas-liquid separator include: closing the solenoid valve on the air pipe at the inlet end of the shutdown indoor unit and the throttling device at the outlet end; opening the solenoid valve on the bypass line connected to the suction port of the compressor, so that the shutdown indoor unit is connected to the gas-liquid separator through the bypass line.

[0064] The solenoid valve is used to control the on-off of the pipeline, which makes it easy to realize automatic control of the solenoid valve through the controller of the multi-connection system, and to realize overall control. The control structure is simpler, the control is more convenient, the degree of automation is higher, and the control efficiency is higher.

[0065] In one embodiment, before the step of controlling the shutdown indoor unit to switch to cooling shutdown, the step also includes: obtaining the shutdown indoor unit information; determining whether the shutdown indoor unit is a VIP indoor unit; the step of controlling the shutdown indoor unit to switch to cooling shutdown includes: when the shutdown indoor unit is a VIP indoor unit, controlling the VIP indoor unit to switch to heating shutdown, and switching other shutdown indoor units to cooling shutdown.

[0066] During the operation of the multi-split system, some indoor units will have the requirement of quick start. If the shutdown indoor unit is switched to cooling shutdown, although the storage of refrigerated oil and refrigerant inside the shutdown indoor unit can be reduced, the refrigerant temperature inside the shutdown indoor unit is also reduced. When the shutdown indoor unit is converted to a working indoor unit, the high-temperature and high-pressure refrigerant discharged from the compressor exhaust port will first heat the low-temperature and low-pressure refrigerant in the shutdown indoor unit when entering the shutdown indoor unit. The two will be neutralized. At this time, the low-temperature and low-pressure refrigerant will cause the high pressure of the shutdown indoor unit to rise slowly when it is converted to a working indoor unit, resulting in a longer startup time and poorer comfort for the converted working indoor unit. Therefore, in this case, the indoor units with rapid heating requirements can be pre-determined, and these indoor units can be used as VIP indoor units. When these VIP indoor units are operating normally When these VIP indoor units are shut down, they are controlled according to normal operation. When these VIP indoor units are shut down, these VIP indoor units continue to be processed separately, and are not switched to cooling shutdown together with other shut down indoor units, but remain in heating shutdown. In this way, due to the small number of VIP indoor units, a small number of VIP indoor units will not cause a large amount of refrigerant and refrigerating oil to be stored in the shut down indoor units, so that the system can still retain sufficient refrigerant and refrigerating oil. At the same time, since these VIP indoor units are shut down for heating, when these VIP indoor units are switched from the shutdown state to the working state, the VIP indoor units also store high-temperature and high-pressure gaseous refrigerant, which can make the refrigerant temperature in these VIP indoor units quickly reach the temperature required for heating operation, thereby realizing rapid heating of these VIP indoor units and improving user comfort.

[0067] In one embodiment, before the step of controlling the operating state of the multi-split system according to the operating mode of the multi-split system, the step also includes: setting a VIP indoor unit.

[0068] The VIP indoor station can be set by the users in each room or by the switchboard.

[0069] In one embodiment, the step of setting the VIP indoor unit includes: receiving VIP indoor unit request information; when the VIP indoor unit request information is obtained, determining a target indoor unit according to the request information; and setting the target indoor unit as the VIP indoor unit.

[0070] In this embodiment, the permission to request VIP setting can be given in each room, so that when the room user needs fast heating, he can request to set the indoor unit of the room as the VIP indoor unit. When the request is approved, the indoor unit will be recorded as a VIP indoor unit at the switchboard. When the multi-split system is running, the indoor unit will be controlled according to the control strategy of the VIP indoor unit in accordance with the aforementioned control method, so that the indoor unit of the room can achieve fast heating and meet the user's usage needs.

[0071] See also Figure 3 and Figure 4 As shown, the multi-split unit used in the multi-split unit control method of the present invention includes an outdoor unit part and an indoor unit part, wherein the outdoor unit part includes a compressor 2, an oil separator 3, a first one-way valve 4, a first four-way valve 5, a second one-way valve 6, a second four-way valve 7, an outdoor unit heat exchanger 8, a fan 9, a heating electronic expansion valve 10, a radiator 11, a subcooler 12, a subcooling electronic expansion valve 13, a high-pressure gas pipe stop valve 32, a low-pressure gas pipe stop valve 33, and a high-pressure liquid pipe stop valve 34. 4. Gas-liquid separator 35 and subcooler solenoid valve 36. The fan 9 is arranged corresponding to the outdoor unit heat exchanger 8. The air inlet end of the gas-liquid separator 35 is also connected to the air supply port of the compressor 2 through an enthalpy increase pipeline. The enthalpy increase pipeline is provided with a subcooler solenoid valve 36 and an enthalpy injection electronic expansion valve 1, wherein the subcooler solenoid valve 36 is arranged on the enthalpy increase pipeline between the subcooler 12 and the gas-liquid separator 35, and the enthalpy injection electronic expansion valve 1 is arranged on the enthalpy increase pipeline close to the air supply port of the compressor 2.

[0072] The indoor unit part includes a first indoor unit 18, a second indoor unit 21, a third indoor unit 27, a first mode converter 14, a second mode converter 24 and a third mode converter 31. The first indoor unit 18 is connected in series with the first mode converter 14, the second indoor unit 21 is connected in series with the second mode converter 24, the third indoor unit 27 is connected in series with the third mode converter 31, and then the three series structures are connected in parallel. The first indoor unit 18 includes a first indoor unit heat exchanger 19 and a first electronic expansion valve 17, and the first electronic expansion valve 17 is a throttling device corresponding to the first indoor unit heat exchanger 19. The second indoor unit 21 includes a second indoor unit heat exchanger 25 and a second electronic expansion valve 20, and the second electronic expansion valve 20 is a throttling device corresponding to the second indoor unit heat exchanger 25. The third indoor unit 27 includes a third indoor unit heat exchanger 28 and a third electronic expansion valve 26, and the third electronic expansion valve 26 is a throttling device corresponding to the third indoor unit heat exchanger 28.

[0073] When A / B<C, the multi-connection operation process is shown in the system working principle Figure 3 As shown, at this time, it is assumed that the first indoor unit 18 is in heating mode, and the second indoor unit 21 and the third indoor unit 27 are in shutdown mode. The system operation process is as follows:

[0074] After the refrigerant flows out of the compressor 2, it flows through the oil separator 3, the first one-way valve 4, the second one-way valve 6, the second four-way valve 7, the high-pressure gas pipe stop valve 32, the second solenoid valve 16, the first indoor unit heat exchanger 19, the first electronic expansion valve 17, the high-pressure liquid pipe stop valve 34, the subcooler 12, the radiator 11, the heating electronic expansion valve 10, the outdoor unit heat exchanger 8, the first four-way valve 5, and the gas-liquid separator 35, and then flows back to the compressor 2 to complete the heating cycle.

[0075] A small amount of high-temperature and high-pressure gaseous refrigerant passes through the third solenoid valve 22 in the second mode converter 24 and the fifth solenoid valve 29 in the third mode converter 31, and is condensed into medium-temperature and high-pressure liquid in the second indoor unit heat exchanger 25 and the third indoor unit heat exchanger 28. At this time, the second electronic expansion valve 20 and the third electronic expansion valve 26 open a smaller step number, so that the refrigerant and refrigeration oil stored in the second indoor unit heat exchanger 25 and the third indoor unit heat exchanger 28 flow out of the indoor unit, and after passing through the second mode converter 24 and the third mode converter 31, flow back to the compressor 2 together with the refrigerant flowing out of the first mode converter 14.

[0076] When A / B≥C and D / B>E, the high capacity ratio heat recovery multi-unit heating system is running at medium to high load. The operation process is shown in the system working principle. Figure 3 As shown, at this time, it is assumed that the first indoor unit 18 is in heating mode, and the second indoor unit 21 and the third indoor unit 27 are in shutdown mode. The system operation process is as follows:

[0077] After the refrigerant flows out of the compressor 2, it flows through the oil separator 3, the first one-way valve 4, the second one-way valve 6, the second four-way valve 7, the high-pressure gas pipe stop valve 32, the second solenoid valve 16, the first indoor unit heat exchanger 19, the first electronic expansion valve 17, the high-pressure liquid pipe stop valve 34, the subcooler 12, the radiator 11, the heating electronic expansion valve 10, the outdoor unit heat exchanger 8, the first four-way valve 5, and the gas-liquid separator 35, and then flows back to the compressor 2 to complete the heating cycle.

[0078] A small amount of high-temperature and high-pressure gaseous refrigerant passes through the third solenoid valve 22 in the second mode converter 24 and the fifth solenoid valve 29 in the third mode converter 31, and is condensed into medium-temperature and high-pressure liquid in the second indoor unit heat exchanger 25 and the third indoor unit heat exchanger 28. At this time, the second electronic expansion valve 20 and the third electronic expansion valve 26 open a smaller step number, so that the refrigerant and refrigeration oil stored in the second indoor unit heat exchanger 25 and the third indoor unit heat exchanger 28 flow out of the indoor unit, and after passing through the second mode converter 24 and the third mode converter 31, flow back to the compressor 2 together with the refrigerant flowing out of the first mode converter 14.

[0079] When A / B≥C and D / B≤E, the system is in low-load operation with high-capacity heat recovery multi-unit heat recovery system. The operation process is shown in the system working principle. Figure 4 At this time, assuming that the first indoor unit 18 is turned on for heating, and the second indoor unit 21 and the third indoor unit 27 are turned off for cooling, the system operation process is:

[0080] After the refrigerant flows out of the compressor 2, it flows through the oil separator 3, the first one-way valve 4, the first four-way valve 5, the second four-way valve 7, the high-pressure gas pipe stop valve 32, the second solenoid valve 16, the first indoor unit heat exchanger 19, the first electronic expansion valve 17, the high-pressure liquid pipe stop valve 34, the subcooler 12, the radiator 11, the heating electronic expansion valve 10, the outdoor unit heat exchanger 8, the first four-way valve 5, and the gas-liquid separator 35, and then flows back to the compressor 2 to complete the heating cycle. At this time, the first solenoid valve 15 of the first mode converter 14 is closed, and the first indoor unit heat exchanger 19 cannot be connected to the air inlet end of the gas-liquid separator 35 through the bypass pipeline.

[0081] At this time, the second indoor unit 21 and the third indoor unit 27, which are in the shutdown state, automatically switch to the refrigeration shutdown state, that is, the third solenoid valve 22 in the second mode converter 24 and the fifth solenoid valve 29 in the third mode converter 31 are closed, the fourth solenoid valve 23 in the second mode converter 24 and the sixth solenoid valve 30 in the third mode converter 31 are opened, the second electronic expansion valve 20 and the third electronic expansion valve 26 are closed, and the refrigerant is no longer circulated. In this case, the flow path of the high-temperature and high-pressure gaseous refrigerant to the second indoor unit heat exchanger 25 and the third indoor unit heat exchanger 28 is cut off, and the high-temperature and high-pressure gaseous refrigerant cannot flow into the second indoor unit heat exchanger 25 and the third indoor unit heat exchanger 28. Therefore, the high-temperature and high-pressure gaseous refrigerant passes through the second solenoid valve 16 of the first mode converter 14 and flows into the first indoor unit heat exchanger 19 of the first indoor unit 18.

[0082] In this state, the third solenoid valve 22 and the fifth solenoid valve 29 are closed, and the high-temperature and high-pressure gaseous refrigerant cannot flow into the second indoor unit 21 through the third solenoid valve 22, nor can it flow into the third indoor unit 27 through the fifth solenoid valve 29. At this time, the fourth solenoid valve 23 and the sixth solenoid valve 30 need to be opened, so that the second indoor unit heat exchanger 25 and the third indoor unit heat exchanger 28 can form a passage with the gas-liquid separator 35 to avoid dead zones in the system. The low-temperature gaseous refrigerant in the gas-liquid separator 35 will flow into the second indoor unit heat exchanger 25 through the fourth solenoid valve 23, and flow into the third indoor unit heat exchanger 28 through the sixth solenoid valve 30. It should be noted here that at this time, the second electronic expansion valve 20 and the third electronic expansion valve 26 of the indoor unit are closed, and the refrigerant state of the second electronic expansion valve 20 and the third electronic expansion valve 26 is the same, that is, the end of the electronic expansion valve away from the indoor unit heat exchanger is medium-temperature and high-pressure liquid refrigerant, and the end close to the indoor unit heat exchanger is low-temperature and low-pressure gaseous refrigerant. Since the refrigerants in the second indoor unit heat exchanger 25 and the third indoor unit heat exchanger 28 are both low-temperature and low-pressure gaseous refrigerants, a large amount of refrigerant will not be stored, so that the refrigerant can flow concentratedly to the first indoor unit 18 serving as the working indoor unit, making the utilization efficiency of the refrigerant higher and effectively improving the system energy efficiency.

[0083] When the high-capacity ratio heat recovery multi-split heating system is running at low load, if the shut-down indoor unit of the refrigeration shutdown is to be converted to the start-up heating operation, taking the second indoor unit 21 that is shut down in the implementation scheme of the high-capacity ratio heat recovery multi-split heating system running at low load as an example, at this time, the fourth solenoid valve 23 in the second mode converter 24 is closed, and the third solenoid valve 22 is opened, and the high-temperature and high-pressure gaseous refrigerant flows into the second indoor unit 21 through the third solenoid valve 22. Since the second indoor unit heat exchanger 25 contains low-temperature and low-pressure gaseous refrigerant, the neutralization of the two will cause the high pressure of the second indoor unit 21 to rise slowly, and the temperature rise rate of the refrigerant will decrease, resulting in a prolonged start-up time of the second indoor unit 21 and poor room comfort. In order to improve this situation, when the heat recovery system is running at high-capacity ratio heating and low load, if a small number of shut-down indoor units need to be started quickly, the corresponding room can be set as a VIP room, and the indoor unit in the VIP room can be set as a VIP indoor unit, and the VIP indoor unit is still defaulted to heating shutdown. In this way, the rooms that need to be heated quickly and preferentially can be determined by marking or recording the indoor units, so that the heating of these VIP indoor units can be kept stopped, and the refrigerant stored in the indoor unit heat exchanger is a high-temperature and high-pressure gaseous refrigerant, so that the temperature difference between the refrigerant stored in the indoor unit heat exchanger and the high-temperature and high-pressure gaseous refrigerant discharged from the exhaust port of the compressor 2 is smaller. When the stopped indoor unit is switched to the working indoor unit, the influence of the refrigerant stored in the indoor unit heat exchanger on the high-temperature and high-pressure gaseous refrigerant can be reduced, thereby achieving rapid heating after the stopped indoor unit is switched to the working indoor unit.

[0084] For the shutdown indoor unit of the refrigeration shutdown mode, one end of the electronic expansion valve is medium-temperature and high-pressure liquid refrigerant, and the other end is low-temperature and low-pressure gaseous refrigerant. If the shutdown indoor unit needs to be switched to heating at this time, the fourth solenoid valve 23 and the sixth solenoid valve 30 need to be closed, and the third solenoid valve 22 and the fifth solenoid valve 29 need to be opened. The high-temperature and high-pressure gaseous refrigerant flows into the second indoor unit 21 through the third solenoid valve 22, and flows into the third indoor unit 27 through the fifth solenoid valve 29. Since there is low-temperature and low-pressure gaseous refrigerant in the shutdown indoor unit, the high-temperature and high-pressure gaseous refrigerant will release heat to the low-temperature and low-pressure gaseous refrigerant as soon as it comes in, resulting in a slower temperature rise in the second indoor unit heat exchanger 25 and the third indoor unit heat exchanger 28, and it takes a long time to reach the set target temperature. Therefore, the startup is slow and the user experience is not good. For users who require quick start of indoor units, the room is specially set as a VIP room, and the stopped indoor unit is set as a VIP indoor unit. The default setting is heating shutdown, so that a part of medium-temperature and high-pressure liquid refrigerant will be stored in the indoor unit heat exchanger. Refer to the system working principle Figure 4 The second indoor unit 21 and the third indoor unit 27 are switched on to heat the indoor unit. High-temperature and high-pressure gaseous refrigerant flows into the indoor unit heat exchanger. The temperature of the indoor unit heat exchanger rises to the set temperature quickly, so that the switched indoor unit can start immediately to achieve rapid heating.

[0085] According to an embodiment of the present invention, a multi-link system is provided, to which the multi-link system control method described above is applied.

[0086] According to an embodiment of the present invention, a storage medium is provided for storing the above-mentioned multi-connection control method.

[0087] The storage medium is, for example, a flash memory, a hard disk, etc.

[0088] The multi-connection control method in the embodiment of the present invention has the following advantages:

[0089] 1. A new multi-split control method is adopted. When the high-capacity heat recovery multi-split unit is running at low load, the stopped indoor unit is switched to cooling shutdown by controlling the mode converter and the electronic expansion valve of the stopped indoor unit. The electronic expansion valve of the stopped indoor unit is closed, and the refrigerant and refrigeration oil no longer flow into the stopped indoor unit, thereby ensuring that there is sufficient refrigeration oil in the system and reducing the risk of oil shortage in the compressor.

[0090] 2. Since the electronic expansion valve of the shut-down indoor unit is closed, all the high-temperature and high-pressure gaseous refrigerant in the system will flow into the working indoor unit in heating operation, increasing the refrigerant flow of the working indoor unit in heating operation, increasing the heat generation of the working indoor unit, and improving the comfort. At the same time, it improves the energy efficiency of the system and saves more energy.

[0091] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0092] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A multi-link control method, characterized in that: include: Determine the operation mode of the multi-link; Controlling the operating state of the multi-link according to the operating mode of the multi-link; When the multi-split operation mode is high capacity ratio heating and low load operation mode, Control the normal operation of the indoor unit; Control the shutdown indoor unit to switch to cooling shutdown, turn off the shutdown indoor unit and the corresponding throttling device, and connect the shutdown indoor unit with the gas-liquid separator; The steps for determining the operation mode of the multi-link system include: Obtain the total capacity A of the indoor unit and the total capacity B of the outdoor unit; When A / B≥C, the multi-link system is judged to be a high-capacity ratio heat recovery multi-link system; When A / B<C, the VRF is judged to be a conventional capacity ratio heat recovery VRF, where C≥110%; Get the total capacity D of the indoor units in heating mode. When D / B≤E, it is judged that the heat recovery multi-connected mechanism is operating at low load; When D / B>E, it is judged that the heat recovery multi-unit heating machine is operating at medium to high load, wherein E≤40%.

2. The multi-link control method according to claim 1, characterized in that: The step of controlling the operating state of the multi-link according to the operating mode of the multi-link also includes: When A / B<C, the working room mechanism is controlled to start heating, and the shutdown room mechanism is controlled to stop heating.

3. The multi-link control method according to claim 1, characterized in that: The step of controlling the operating state of the multi-link according to the operating mode of the multi-link also includes: When A / B≥C and D / B>E, the working room mechanism is controlled to start heating, and the shutdown room mechanism is controlled to stop heating.

4. The multi-link control method according to claim 1, characterized in that: When A / B≥C and D / B≤E, the operation mode of the multi-split system is determined to be a high capacity ratio heating and low load operation mode.

5. The multi-link control method according to claim 4, characterized in that: The steps of controlling the shutdown indoor unit to switch to cooling shutdown, closing the shutdown indoor unit and the corresponding throttling device, and connecting the shutdown indoor unit with the gas-liquid separator include: closing the solenoid valve on the gas pipe at the inlet end and the throttling device at the outlet end of the shutdown indoor unit; The solenoid valve on the bypass pipeline connected to the air intake of the compressor is opened, so that the stopped indoor unit is connected to the gas-liquid separator through the bypass pipeline.

6. The multi-link control method according to claim 1, characterized in that: The step of controlling the shutdown indoor unit to switch to cooling shutdown also includes: Get the information of the stopped indoor unit; Determine whether the stopped indoor unit is a VIP indoor unit; The steps of controlling the shutdown indoor unit to switch to cooling shutdown include: When the stopped indoor unit is a VIP indoor unit, the VIP indoor unit is controlled to switch to heating shutdown, and other stopped indoor units are switched to cooling shutdown.

7. The multi-link control method according to claim 6, characterized in that: Before the step of controlling the operating state of the multi-link according to the operating mode of the multi-link, the method further includes: Set up VIP indoor unit.

8. The multi-link control method according to claim 7, characterized in that: The steps of setting the VIP indoor station include: receiving VIP indoor station request information; When the VIP indoor unit request information is obtained, the target indoor unit is determined according to the request information; Set the target indoor unit as the VIP indoor unit.

9. The multi-link control method according to claim 1, characterized in that: C=135%, E=30%.

10. A multi-link system, characterized in that: The multi-connection control method according to any one of claims 1 to 9 is applied.

11. A storage medium, characterized in that: Used to store the multi-connection control method described in any one of claims 1 to 9.

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