Heat pump system and control method and control device thereof

Abstract

The invention provides a heat pump system and a control method and device thereof. The heat pump system comprises a high-pressure-stage compressor, a low-pressure-stage compressor, an air side heat exchanger, a first throttling valve and a water side heat exchanger which are connected through a refrigerant main path. A first branch connected with the refrigerant main path in parallel is arranged between the water side heat exchanger and the first economizer, and the first branch flows through the first economizer and communicates with an air suction port of the high-pressure-stage compressor. A second branch which is connected with the refrigerant main path in parallel is arranged between the first economizer and the second economizer; the second branch flows through the second economizer and is communicated to an air supply port of the low-pressure-stage compressor; the first branch is provided with a second throttle valve, and the second branch is provided with a third throttle valve. The problem of insufficient heating capacity during low-environment operation can be well solved, the user experience is improved, meanwhile, the four operation modes can well accord with the operation working conditions of the whole heating season, and high-energy-efficiency operation of the whole heating season is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of electrical appliances, and particularly to a heat pump system, a control method thereof, and a control device thereof. Background Art

[0002] Traditional heat pump systems face challenges when operating at extremely low ambient temperatures. At this time, the evaporation temperature of the refrigerant is lower, resulting in a decrease in the density of the refrigerant. Consequently, the mass flow rate of the refrigerant inhaled by the compressor decreases, thereby affecting the output of the heating capacity and failing to meet the heating demands of users. This phenomenon is particularly prominent in extremely cold regions during winter, affecting the overall performance of the heat pump system and the heating experience of users. Summary of the Invention

[0003] The present invention provides a heat pump system, a control method thereof, and a control device thereof to solve the defects existing in the prior art and achieve the following technical effects: single compressor operation, gas injection enhanced enthalpy quasi two-stage operation of a single compressor, fully two-stage operation of two compressors, and gas injection enhanced enthalpy operation of two compressors and a low-pressure compressor can be realized. This solution can preferably solve the problem of insufficient heating capacity during low ambient temperature operation, improve the user experience. At the same time, the four operation modes can preferably match the operation conditions throughout the heating season, achieving high energy efficiency operation throughout the heating season.

[0004] The heat pump system according to the first aspect embodiment of the present invention includes a high-pressure stage compressor, a low-pressure stage compressor, an air-side heat exchanger, a first throttle valve, and a water-side heat exchanger connected through a main refrigerant circuit; The air-side heat exchanger is connected to the suction port of the low-pressure stage compressor. The discharge port of the low-pressure stage compressor is connected to the suction port of the high-pressure stage compressor. The discharge port of the high-pressure stage compressor is connected to the water-side heat exchanger. A first economizer and a second economizer are provided between the water-side heat exchanger and the air-side heat exchanger; Wherein, a first branch parallel to the main refrigerant circuit is provided between the water-side heat exchanger and the first economizer. The first branch flows through the first economizer and is connected to the suction port of the high-pressure stage compressor; a second branch parallel to the main refrigerant circuit is provided between the first economizer and the second economizer. The second branch flows through the second economizer and is connected to the gas injection port of the low-pressure stage compressor; and a second throttle valve is provided on the first branch, and a third throttle valve is provided on the second branch.

[0005] According to an embodiment of the present invention, a third branch is connected in parallel on both sides of the high-pressure stage compressor. A check valve is provided on the third branch, and the valve direction of the check valve is oriented along the direction from the suction port to the discharge port of the high-pressure stage compressor.

[0006] According to an embodiment of the present invention, the heat pump system further includes: Four-way valve, the four interfaces of the four-way valve are respectively connected to the exhaust port of the high-pressure stage compressor, the water-side heat exchanger, the air-side heat exchanger, and the suction port of the low-pressure stage compressor.

[0007] According to an embodiment of the present invention, the heat pump system further includes: Ambient temperature sensor and outlet water temperature sensor; Control device, connected to the ambient temperature sensor and the outlet water temperature sensor, for obtaining the ambient temperature and the outlet water temperature, and controlling and adjusting the working mode and its working parameters of the heat pump system according to the ambient temperature and the outlet water temperature.

[0008] According to the control method of the heat pump system based on the first aspect embodiment of the present invention in the second aspect embodiment of the present invention, it includes: Obtain the ambient temperature of the environment where the heat pump system is located; According to the ambient temperature, control and adjust the working mode of the heat pump system; In the current working mode, obtain the actual outlet water temperature of the heat pump system; According to the actual outlet water temperature, control and adjust the working parameters of the low-pressure stage compressor and / or the high-pressure stage compressor; Wherein, in different working modes, the opening and closing conditions of the first throttle valve, the second throttle valve, and the third throttle valve are different.

[0009] According to an embodiment of the present invention, the step of controlling and adjusting the working mode of the heat pump system according to the ambient temperature specifically includes: When the ambient temperature is greater than or equal to the first set temperature, control and adjust the heat pump system to enter the first heating mode in which the low-pressure stage compressor operates alone without increasing enthalpy; Wherein, in the first heating mode, control the high-pressure stage compressor to be closed and the low-pressure stage compressor to be opened, and control the second throttle valve and the third throttle valve to be closed and the first throttle valve to be opened.

[0010] According to an embodiment of the present invention, the step of controlling and adjusting the working mode of the heat pump system according to the ambient temperature specifically includes: When the ambient temperature is less than the first set temperature and greater than the second set temperature, control and adjust the heat pump system to enter the second heating mode in which the low-pressure stage compressor operates alone with enthalpy increase; Wherein, in the second heating mode, control the high-pressure stage compressor to be closed and the low-pressure stage compressor to be opened, and control the third throttle valve to be closed and the first throttle valve and the second throttle valve to be opened.

[0011] According to an embodiment of the present invention, the step of controlling and adjusting the operating parameters of the low-pressure stage compressor and / or the high-pressure stage compressor according to the actual water outlet temperature specifically includes: In the first heating mode or the second heating mode, according to the comparison result between the actual water outlet temperature and the target water outlet temperature, control and adjust the operating frequency of the low-pressure stage compressor so that the actual water outlet temperature is maintained at the target water outlet temperature.

[0012] According to an embodiment of the present invention, after the step of controlling and adjusting the operating parameters of the low-pressure stage compressor and / or the high-pressure stage compressor according to the actual water outlet temperature, it further includes: In the first heating mode, after the actual water outlet temperature is less than or equal to the target water outlet temperature and lasts for at least the first set duration, control the second throttle valve to open so that the heat pump system switches to the second heating mode.

[0013] According to an embodiment of the present invention, after the step of controlling and adjusting the operating parameters of the low-pressure stage compressor and / or the high-pressure stage compressor according to the actual water outlet temperature, it further includes: In the second heating mode, after the actual water outlet temperature is less than or equal to the target water outlet temperature and lasts for at least the second set duration, control the high-pressure stage compressor to start and the third throttle valve to open so that the heat pump system switches to the fourth heating mode; Wherein, the fourth heating mode is a heating mode in which the two-stage compressor operates simultaneously and the low-pressure stage compressor turns on the enthalpy increase.

[0014] According to an embodiment of the present invention, the step of controlling and adjusting the operating mode of the heat pump system according to the ambient temperature specifically includes: When the ambient temperature is less than the second set temperature, control and adjust the heat pump system to enter the third heating mode in which the two-stage compressor operates simultaneously and the low-pressure stage compressor does not turn on the enthalpy increase; Wherein, in the third heating mode, control both the high-pressure stage compressor and the low-pressure stage compressor to start, control the first throttle valve and the third throttle valve to open and the second throttle valve to close.

[0015] According to an embodiment of the present invention, the step of controlling and adjusting the operating parameters of the low-pressure stage compressor and / or the high-pressure stage compressor according to the actual water outlet temperature specifically includes: In the third heating mode, according to the comparison result between the actual water outlet temperature and the target water outlet temperature, control and adjust the operating frequencies of the high-pressure stage compressor and the low-pressure stage compressor so that the actual water outlet temperature is maintained at the target water outlet temperature.

[0016] After the step of controlling and adjusting the operating parameters of the low-pressure stage compressor and / or the high-pressure stage compressor according to the actual water outlet temperature according to an embodiment of the present invention, the method further includes: In the third heating mode, after the actual water outlet temperature is less than or equal to the target water outlet temperature and lasts for at least a third set duration, control the second throttle valve to open so that the heat pump system switches to the fourth heating mode; Wherein, the fourth heating mode is a heating mode in which the two-stage compressor operates simultaneously and the low-pressure stage compressor is enthalpy-increasing.

[0017] The control device of the heat pump system according to the third aspect embodiment of the present invention based on the heat pump system according to the first aspect embodiment of the present invention includes: A first acquisition module for acquiring the ambient temperature of the environment where the heat pump system is located; A first control module for controlling and adjusting the operating mode of the heat pump system according to the ambient temperature; A second acquisition module for acquiring the actual water outlet temperature of the heat pump system in the current operating mode; A second control module for controlling and adjusting the operating parameters of the low-pressure stage compressor and / or the high-pressure stage compressor according to the actual water outlet temperature; Wherein, in different operating modes, the opening and closing conditions of the first throttle valve, the second throttle valve and the third throttle valve are different.

[0018] In summary, the heat pump system according to the embodiment of the present invention has at least the following advantages.

[0019] (1) Efficiently cope with low-temperature environments: Through the two-stage compression design and the gas injection and enthalpy-increasing technology, the problem of insufficient heat output of the heat pump in extremely cold weather is effectively solved, ensuring good heating efficiency at low ambient temperatures and improving the user experience in cold seasons.

[0020] (2) Flexible and diverse operating modes: The system has multiple modes such as single compressor operation, single compressor gas injection and enthalpy-increasing quasi two-stage operation, two compressors full two-stage operation, and two compressors and low-pressure stage compressor gas injection and enthalpy-increasing operation, which can be automatically switched according to actual environmental conditions to achieve high-efficiency operation throughout the heating season.

[0021] (3) Optimized system energy efficiency: Through the ingenious design of the first and second economizers, efficient heat exchange of the refrigerant is achieved. It not only effectively controls the suction temperature of the high-pressure stage compressor, avoiding the risk of overheating, but also improves the suction efficiency of the low-pressure stage compressor through gas injection and enthalpy-increasing, and overall improves the energy efficiency ratio of the system.

[0022] (4) Intelligent control strategy: By integrating the ambient temperature sensor and the water temperature sensor, the compressor frequency is automatically adjusted to ensure that the water temperature is maintained within the set range, which not only guarantees the heating effect but also maximizes the energy efficiency. At the same time, the operating mode is automatically switched according to the ambient temperature change, improving the system's intelligence level and user convenience.

[0023] (5) Enhancing system reliability: Through the design of mixing the refrigerant in the first branch with the exhaust gas of the low-pressure stage compressor to reduce the suction temperature of the high-pressure stage compressor, the risk of unstable operation or even damage of the high-pressure stage compressor caused by too high suction temperature is effectively avoided, improving the reliability and service life of the entire system.

[0024] (6) Expanding functions and compatibility: The present invention takes into account the expandability of the system. For example, by adding a four-way valve to achieve refrigeration and defrosting functions, as well as different economizer schemes and compressor parallel operation schemes, the versatility of the system and its adaptability in different application scenarios are enhanced. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0026] Figure 1 It is a schematic structural diagram of a heat pump system provided by an embodiment of the present invention.

[0027] Figure 2 It is a schematic structural diagram of a heat pump system provided by another embodiment of the present invention.

[0028] Figure 3 It is a schematic flow diagram of the control method of the heat pump system provided by the present invention.

[0029] Figure 4 It is a schematic structural diagram of the control device of the heat pump system provided by the present invention.

[0030] Figure 5 It is a schematic structural diagram of the electronic device provided by the present invention.

[0031] Description: 1. Low-pressure stage compressor; 2. High-pressure stage compressor; 3. Water-side heat exchanger; 4. Air-side heat exchanger; 5. Four-way valve; 6. First economizer; 7. Second economizer; 8. Main refrigerant circuit; 9. First branch; 10. Second branch; 11. Third branch; 12. First throttle valve; 13. Second throttle valve; 14. Third throttle valve; 15. Check valve; 110. First acquisition module; 120. First control module; 130. Second acquisition module; 140. Second control module. Detailed implementation manners

[0032] In the description of this specification, the descriptions with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the embodiments of the present invention. In this specification, the schematic representations of the above terms are not necessarily directed to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0033] The heat pump system proposed by the present invention, as well as the control method and control device based on the heat pump system, are given below with reference to the accompanying drawings.

[0034] As Figure 1 and 2 shown, the heat pump system according to the first aspect embodiment of the present invention includes a high-pressure stage compressor 2, a low-pressure stage compressor 1, an air-side heat exchanger 4, a first throttle valve 12, and a water-side heat exchanger 3 connected through a main refrigerant circuit 8.

[0035] The air-side heat exchanger 4 is communicated with the suction port of the low-pressure stage compressor 1, the discharge port of the low-pressure stage compressor 1 is communicated with the suction port of the high-pressure stage compressor 2, the discharge port of the high-pressure stage compressor 2 is communicated with the water-side heat exchanger 3, and a first economizer 6 and a second economizer 7 are arranged between the water-side heat exchanger 3 and the air-side heat exchanger 4.

[0036] Wherein, a first branch 9 parallel to the main refrigerant circuit 8 is provided between the water-side heat exchanger 3 and the first economizer 6. The first branch 9 flows through the first economizer 6 and is communicated with the suction port of the high-pressure stage compressor 2; a second branch 10 parallel to the main refrigerant circuit 8 is provided between the first economizer 6 and the second economizer 7. The second branch 10 flows through the second economizer 7 and is communicated with the gas supplement port of the low-pressure stage compressor 1; and a second throttle valve 13 is provided on the first branch 9, and a third throttle valve 14 is provided on the second branch 10.

[0037] The specific working principle and process of the heat pump system according to the embodiments of the present invention are as follows: In the heating mode of the heat pump system, the water-side heat exchanger 3 serves as the condenser, and the air-side heat exchanger 4 serves as the evaporator. The high-pressure medium-temperature refrigerant flowing out of the water-side heat exchanger 3 is divided into two parts. One part of the refrigerant enters the first branch 9 and passes through the second throttle valve 13 to become a low-temperature and low-pressure gas-liquid mixture, and the other part of the refrigerant enters the main refrigerant path 8 and passes through the first economizer 6. At this time, in the first economizer 6, the high-temperature and medium-pressure refrigerant in the main refrigerant path 8 exchanges heat with the low-temperature and low-pressure gas-liquid mixture in the first branch 9.

[0038] Among them, for the refrigerant in the main refrigerant path 8, since a part of the refrigerant in the main refrigerant path 8 will be separated after flowing out of the first economizer 6 to be replenished into the gas inlet of the low-pressure stage compressor 1 through the second branch 10, the existence of the first economizer 6 can make the gas-liquid mixture replenished into the low-pressure stage compressor 1 have a higher dryness, so as to avoid the risk of liquid hammer on the low-pressure stage compressor 1.

[0039] For the refrigerant in the first branch 9, after the refrigerant in the first branch 9 flows out of the first economizer 6, it will be mixed with the exhaust gas of the low-pressure stage compressor 1 and enter the suction port of the high-pressure stage compressor 2 together. At this time, the suction temperature of the high-pressure stage compressor 2 can be reduced. It can be understood that in order to ensure the reliable operation of the two-stage compression heat pump, the exhaust gas of the high-pressure stage compressor 2 cannot be too high and needs to be less than the maximum allowable exhaust value of the compressor. Therefore, it is necessary to cool the suction of the high-pressure stage compressor 2. The existence of the above-mentioned first branch 9 can use the low-temperature and low-pressure refrigerant to be mixed with the exhaust gas of the low-pressure stage compressor 1 to reduce the refrigerant temperature, and then reduce the suction temperature of the high-pressure stage compressor 2.

[0040] The refrigerant in the main refrigerant path 8 is divided into two parts again after being subcooled by the first economizer 6. Among them, one part of the refrigerant enters the second branch 10 and passes through the third throttle valve 14 to further cool down and reduce the pressure, and finally replenishes into the gas inlet of the low-pressure stage compressor 1, thereby playing a role in gas replenishment, while the other part of the high-temperature and medium-pressure refrigerant continues to flow through the main refrigerant path 8 and passes through the second economizer 7 to exchange heat with the refrigerant whose temperature and pressure are reduced in the second branch 10, thereby playing a role in enthalpy increase. After the refrigerant in the main refrigerant path 8 flows out of the second economizer 7, it passes through the first throttle valve 12 and finally enters the suction port of the low-pressure stage compressor 1.

[0041] In summary, the heat pump system according to the embodiments of the present invention has at least the following advantages.

[0042] (1) Efficiently cope with low-temperature environments: Through the two-stage compression design and the gas replenishment and enthalpy increase technology, the problem of insufficient heat output of the heat pump in extremely cold weather is effectively solved, ensuring good heating efficiency even at low ambient temperatures and improving the user experience in cold seasons.

[0043] (2) Flexible and diverse operation modes: The system has multiple modes such as single compressor operation, single compressor gas-injected enthalpy-increasing quasi-two-stage operation, two-compressor full two-stage operation, and two-compressor and low-pressure stage compressor gas-injected enthalpy-increasing operation. It can automatically switch according to the actual environmental conditions to achieve high-efficiency operation throughout the heating season.

[0044] (3) Optimized system energy efficiency: Through the ingenious design of the first and second economizers 7, efficient heat exchange of the refrigerant is achieved. It not only effectively controls the suction temperature of the high-pressure stage compressor 2, avoiding the risk of overheating, but also improves the suction efficiency of the low-pressure stage compressor 1 through gas-injected enthalpy-increasing, thereby overall improving the energy efficiency ratio of the system.

[0045] (4) Intelligent control strategy: Combining the ambient temperature sensor and the water temperature sensor, it automatically adjusts the compressor frequency to ensure that the water temperature is maintained within the set range. This not only guarantees the heating effect but also realizes the maximization of energy efficiency. At the same time, it automatically switches the operation mode according to the change of ambient temperature, improving the intelligent level and user convenience of the system.

[0046] (5) Enhanced system reliability: Through the design of mixing the refrigerant in the first branch 9 with the exhaust gas of the low-pressure stage compressor 1 to reduce the suction temperature of the high-pressure stage compressor 2, the risk of unstable operation or even damage of the high-pressure stage compressor 2 caused by too high suction temperature is effectively avoided, improving the reliability and service life of the entire system.

[0047] (6) Extended functions and compatibility: The present invention takes into account the scalability of the system. For example, by adding a four-way valve 5 to achieve refrigeration and defrosting functions, as well as different economizer schemes and compressor parallel operation schemes, the versatility of the system and its adaptability in different application scenarios are enhanced.

[0048] The heat pump system of the present invention, through innovative structural design and advanced control logic, not only significantly improves the heating performance of the heat pump in low-temperature environments, but also takes into account energy efficiency, reliability, intelligent control, and system flexibility, providing a new solution for the development of heat pump technology.

[0049] As Figure 1 and 2 shown, according to some embodiments of the present invention, a third branch 11 is connected in parallel on both sides of the high-pressure stage compressor 2. A check valve 15 is provided on the third branch 11, and the valve direction of the check valve 15 is oriented along the direction from the suction port to the exhaust port of the high-pressure stage compressor 2.

[0050] In this embodiment, when the high-pressure stage compressor 2 stops operating, the refrigerant discharged from the exhaust port of the low-pressure stage compressor 1 can pass through the third branch 11, and successively flow through the water-side heat exchanger 3, the first economizer 6, the second economizer 7, the first throttle valve 12, and finally return to the suction port of the low-pressure stage compressor 1, thus completing a normal heating cycle.

[0051] In this way, the presence of the third branch 11 enables the switching of whether the high-pressure stage compressor 2 stops or not, so that the heat pump system has multiple heating operation modes, facilitating users to select a suitable heating operation mode according to requirements and usage restrictions to meet the heating demand. The presence of the check valve 15 can avoid problems such as reverse flow and reflux of the refrigerant, ensuring the safe use of the system.

[0052] For the heat pump system of the present invention, two specific heat pump system structures are given in this embodiment.

[0053] As Figure 1 shown, the first is the heat pump system structure that can only heat. In the first structure, there is no four-way valve 5. Specifically, the heat pump system includes a low-pressure stage compressor 1, a high-pressure stage compressor 2, a water-side heat exchanger 3, a first economizer 6, a second economizer 7, and a throttle valve that are sequentially connected through a refrigerant main path 8. Among them, the first branch 9 is led out from the outlet of the water-side heat exchanger 3, and sequentially flows through the second throttle valve 13 and the first economizer 6 and finally converges into the suction port of the high-pressure stage compressor 2; the second branch 10 is led out from the outlet of the first economizer 6, and sequentially flows through the third throttle valve 14 and the second economizer 7 and finally converges into the gas supplement port of the low-pressure stage compressor 1. The third branch 11 with a check valve 15 is connected in parallel on both sides of the high-pressure stage compressor 2.

[0054] As Figure 2 shown, the second is the heat pump system structure that can both heat and cool. In the second structure, a four-way valve 5 is provided. Specifically, the four interfaces of the four-way valve 5 are respectively connected to the exhaust port of the high-pressure stage compressor 2, the water-side heat exchanger 3, the air-side heat exchanger 4, and the suction port of the low-pressure stage compressor 1. The high-pressure stage compressor 2 and the low-pressure stage compressor 1 are connected in series, and the water-side heat exchanger 3, the first economizer 6, the second economizer 7, the first throttle valve 12, and the air-side heat exchanger 4 are sequentially connected in series. Among them, the connection structures of the first branch 9, the second branch 10, and the third branch 11 are similar to those in the first heat pump system and will not be elaborated here.

[0055] According to some embodiments of the present invention, the heat pump system further includes an ambient temperature sensor, a water outlet temperature sensor, and a control device.

[0056] The control device is connected to the ambient temperature sensor and the water outlet temperature sensor, and is used to obtain the ambient temperature and the water outlet temperature, and control and adjust the working mode and working parameters of the heat pump system according to the ambient temperature and the water outlet temperature.

[0057] Among them, the heat pump system of the present invention can change the working mode by changing the opening and closing conditions of the first throttle valve 12, the second throttle valve 13, and the third throttle valve 14, and by changing the opening and closing conditions of the two compressors.

[0058] Specifically, as Figure 1 shown, taking the first heat pump structure that can only heat as an example of the heat pump system, the working modes of the heat pump system are introduced as follows: (1) First heating mode: The low-pressure stage compressor 1 operates alone without enthalpy increase.

[0059] In the first heating mode, the high-pressure stage compressor 2 is closed and the low-pressure stage compressor 1 is turned on. The second throttle valve 13 and the third throttle valve 14 are closed and the first throttle valve 12 is opened.

[0060] The refrigerant flow path in the first heating mode is as follows: For the main refrigerant path 8, the refrigerant flowing out of the exhaust port of the low-pressure stage compressor 1 enters the third branch 11, and flows through the check valve 15 to the water-side heat exchanger 3. After flowing out of the water-side heat exchanger 3, the refrigerant passes through the first economizer 6, the second economizer 7 and the first throttle valve 12 in sequence, and enters the air-side heat exchanger 4. Finally, the refrigerant flowing out of the air-side heat exchanger 4 enters the suction port of the low-pressure stage compressor 1 to complete a heating cycle.

[0061] For the first branch 9 and the second branch 10, since the second throttle valve 13 and the third throttle valve 14 are closed, there is no refrigerant flow in the first branch 9 and the second branch 10.

[0062] (2) Second heating mode: The low-pressure stage compressor 1 operates alone with enthalpy increase.

[0063] In the first heating mode, the high-pressure stage compressor 2 is closed and the low-pressure stage compressor 1 is turned on. The second throttle valve 13 is closed and the first throttle valve 12 and the third throttle valve 14 are opened.

[0064] The refrigerant flow path in the second heating mode is as follows: For the main refrigerant path 8, the refrigerant flowing out of the exhaust port of the low-pressure stage compressor 1 enters the third branch 11, and flows through the check valve 15 to the water-side heat exchanger 3. After flowing out of the water-side heat exchanger 3, the refrigerant passes through the first economizer 6, the second economizer 7 and the first throttle valve 12 in sequence, and enters the air-side heat exchanger 4. Finally, the refrigerant flowing out of the air-side heat exchanger 4 enters the suction port of the low-pressure stage compressor 1 to complete a heating cycle.

[0065] For the first branch 9, since the second throttle valve 13 is closed, there is no refrigerant flow in the first branch 9.

[0066] For the second branch 10, part of the refrigerant flowing out of the first economizer 6 enters the second branch 10, and after throttling, cooling and pressure reduction by the second throttle valve 13, finally enters the gas injection port of the low-pressure stage compressor 1.

[0067] (3) Third heating mode: The two-stage compressor operates simultaneously and the low-pressure stage compressor 1 does not turn on the enthalpy increase.

[0068] In the third heating mode, both the high-pressure stage compressor 2 and the low-pressure stage compressor 1 are turned on, the first throttle valve 12 and the third throttle valve 14 are turned on and the second throttle valve 13 is closed.

[0069] The refrigerant flow path in the third heating mode is as follows: For the main refrigerant path 8, the refrigerant flowing out of the exhaust port of the low-pressure stage compressor 1 is mixed with the refrigerant in the first branch 9 to cool down. The cooled refrigerant enters the suction port of the high-pressure stage compressor 2. The refrigerant flowing out of the exhaust port of the high-pressure stage compressor 2 continues to flow to the water-side heat exchanger 3. After flowing out of the water-side heat exchanger 3, the refrigerant passes through the first economizer 6, the second economizer 7 and the first throttle valve 12 in sequence, and enters the air-side heat exchanger 4. Finally, the refrigerant flowing out of the air-side heat exchanger 4 enters the suction port of the low-pressure stage compressor 1 to complete a heating cycle.

[0070] For the first branch 9, a part of the refrigerant flowing out of the water-side heat exchanger 3 enters the first branch 9, is throttled by the second throttle valve 13 to cool down and reduce the pressure, and the cooled and pressure-reduced refrigerant continues to pass through the first branch 9 to be mixed with the exhaust of the low-pressure stage compressor 1 to reduce the suction temperature of the high-pressure stage compressor 2. It can be understood that in order to ensure the reliable operation of the two-stage compression heat pump, the exhaust of the high-pressure stage compressor 2 cannot be too high and needs to be less than the maximum allowable exhaust value of the compressor. Therefore, it is necessary to cool down the suction of the high-pressure stage compressor 2.

[0071] For the second branch 10, due to the closing of the third throttle valve 14, there is no refrigerant flowing in the second branch 10.

[0072] (4) Fourth heating mode: The two-stage compressor operates simultaneously and the low-pressure stage compressor 1 turns on the enthalpy increase.

[0073] In the fourth heating mode, both the high-pressure stage compressor 2 and the low-pressure stage compressor 1 are turned on, and the first throttle valve 12, the second throttle valve 13 and the third throttle valve 14 are turned on.

[0074] The refrigerant flow path in the fourth heating mode is as follows: For the main refrigerant path 8, the refrigerant flowing out of the exhaust port of the low-pressure stage compressor 1 is mixed with the refrigerant in the first branch 9 to cool down. The cooled refrigerant enters the suction port of the high-pressure stage compressor 2. The refrigerant flowing out of the exhaust port of the high-pressure stage compressor 2 continues to flow to the water-side heat exchanger 3. After flowing out of the water-side heat exchanger 3, the refrigerant passes through the first economizer 6, the second economizer 7 and the first throttle valve 12 in sequence, and enters the air-side heat exchanger 4. Finally, the refrigerant flowing out of the air-side heat exchanger 4 enters the suction port of the low-pressure stage compressor 1 to complete a heating cycle.

[0075] For the first branch 9, part of the refrigerant flowing out of the water-side heat exchanger 3 enters the first branch 9, is throttled by the second throttle valve 13 to reduce the temperature and pressure, and the refrigerant after reducing the temperature and pressure continues to mix with the exhaust gas of the low-pressure stage compressor 1 through the first branch 9, reducing the suction temperature of the high-pressure stage compressor 2.

[0076] For the second branch 10, part of the refrigerant flowing out of the first economizer 6 enters the second branch 10, is throttled by the second throttle valve 13 to reduce the temperature and pressure, and finally enters the gas supplement port of the low-pressure stage compressor 1.

[0077] In summary, for the heat pump system according to the embodiment of the present invention, by adopting the gas injection enthalpy increase circuit, single-compressor operation, gas injection enthalpy increase quasi-two-stage operation of a single compressor, fully two-stage operation of two compressors, and gas injection enthalpy increase operation of two compressors and a low-pressure compressor can be realized. This solution can better solve the problem of insufficient heating capacity during low ambient operation, improve the user experience, and at the same time, the four heating operation modes can better fit the operating conditions of the entire heating season, meeting the high energy efficiency operation of the entire heating season.

[0078] Next, the control method, control device and heat pump system of the heat pump system proposed by the present invention will be described with reference to the accompanying drawings. Among them, before the embodiments of the present invention are described in detail, the entire application scenario will be described first. The control method, control device, electronic device and computer-readable storage medium of the heat pump system according to the embodiments of the present invention can be applied not only to the local heat pump system, but also to the cloud platform in the Internet field, or the cloud platform in other types of Internet fields, or can also be applied to third-party devices. Among them, the third-party devices may include various different types such as mobile phones, tablet computers, notebooks, in-vehicle computers and other intelligent terminals.

[0079] Next, only the control method applicable to the heat pump system will be used as an example for illustration. It should be understood that the control method of the embodiments of the present invention can also be applied to the cloud platform and third-party devices.

[0080] As Figure 3 shown, the control method of the heat pump system according to the second aspect embodiment of the present invention includes: Step S1, obtaining the ambient temperature of the environment where the heat pump system is located; Step S2, controlling and adjusting the working mode of the heat pump system according to the ambient temperature; Step S3, obtaining the actual water outlet temperature of the heat pump system in the current working mode; Step S4, controlling and adjusting the working parameters of the low-pressure stage compressor 1 and / or the high-pressure stage compressor 2 according to the actual water outlet temperature.

[0081] Among them, in different working modes, the opening and closing conditions of the first throttle valve 12, the second throttle valve 13 and the third throttle valve 14 are different.

[0082] The control method of the heat pump system according to the embodiment of the present invention has the following specific working process: The system uses an ambient temperature sensor (Ta) to continuously monitor the temperature of the surrounding environment. Ambient temperature is one of the key factors determining the operating mode and efficiency of the heat pump. Especially under extreme weather conditions, accurately grasping the ambient temperature is crucial for the performance of the heat pump system.

[0083] The system determines the most suitable working mode based on the detected ambient temperature (Ta). For example, when the ambient temperature is relatively high (Ta≥Ta1), only the low-pressure stage compressor 1 may be required for heating; when the temperature is moderate (Ta2<Ta<Ta1), the boosting enthalpy operation of the low-pressure stage compressor 1 is enabled; and at extremely low temperatures (Ta<Ta2), it switches to the two-stage series heating mode. Such dynamic adjustment ensures the efficient operation of the system under various climate conditions.

[0084] In step S3, a water temperature sensor (Tw) is used to monitor the temperature of the water discharged from the heat pump system in real time. This is a direct indicator of the heat pump's heating efficiency and an important basis for adjusting the system. If the water outlet temperature deviates from the set target temperature (Tw0±△T), the system will take measures for correction.

[0085] When it is detected that the actual water outlet temperature deviates from the set target range, the system will adjust the operating parameters of the low-pressure stage compressor 1 and / or the high-pressure stage compressor 2, such as changing the frequencies (f1, f2) of the compressors to adjust the flow rate and pressure of the refrigerant, thereby controlling the heat output and ensuring that the water outlet temperature is stabilized within the desired range. This immediate feedback mechanism can quickly respond to changes in external conditions and maintain the efficient and stable operation of the system.

[0086] It should be explained that in different working modes, the opening and closing conditions of the first throttle valve 12, the second throttle valve 13, and the third throttle valve 14 will be different to adapt to the requirements of the refrigerant circulation path in different modes. For example, in the heating mode with only the low-pressure stage compressor 1, the second throttle valve 13 and the third throttle valve 14 may need to be closed; while in the two-stage series heating mode, these valves need to be opened to achieve effective boosting enthalpy and temperature regulation of the refrigerant. This dynamic valve control strategy is an important part of the efficient operation of the heat pump system, and by finely regulating the refrigerant flow, the purpose of optimizing the system performance is achieved.

[0087] In an embodiment of the present invention, the step of controlling and adjusting the working mode of the heat pump system according to the ambient temperature specifically includes: When the ambient temperature is greater than or equal to the first set temperature, control and adjust the heat pump system to enter the first heating mode in which the low-pressure stage compressor 1 operates alone without boosting enthalpy.

[0088] Among them, in the first heating mode, the high-pressure stage compressor 2 is controlled to be closed and the low-pressure stage compressor 1 is controlled to be turned on, and the second throttle valve 13 and the third throttle valve 14 are controlled to be closed and the first throttle valve 12 is controlled to be turned on.

[0089] In this embodiment, considering that when the ambient temperature is relatively high, there is no need for the additional boosting capacity provided by the two-stage compression to improve the heating efficiency, the system will turn off the high-pressure stage compressor 2. This can reduce unnecessary energy consumption and lower the system operation cost. At the same time, the low-pressure stage compressor 1 operates alone, responsible for the refrigerant cycle of the entire system. This simplifies the circulation path, reduces energy loss, and also simplifies the system control logic.

[0090] In addition, to match the needs of the low-pressure stage compressor 1 operating alone, the second throttle valve 13 and the third throttle valve 14 will be closed. This means that the refrigerant will not pass through these two branches for gas replenishment or additional heat exchange, but directly circulate through the main path. And the first throttle valve 12 is turned on. It is located in the main path and is responsible for regulating the refrigerant flow rate and pressure to ensure the normal suction of the low-pressure stage compressor 1 and the efficient circulation of the system.

[0091] In this way, through the above measures, when the ambient temperature is relatively suitable, the heat pump system adopts a more concise and efficient operation strategy, aiming to maximize the coefficient of performance, reduce energy consumption, and maintain stable heating performance at the same time.

[0092] In another embodiment of the present invention, the steps of controlling and adjusting the working mode of the heat pump system according to the ambient temperature specifically include: When the ambient temperature is less than the first set temperature and greater than the second set temperature, control and adjust the heat pump system to enter the second heating mode in which the low-pressure stage compressor 1 operates alone and the enthalpy is increased.

[0093] Among them, in the second heating mode, the high-pressure stage compressor 2 is controlled to be closed and the low-pressure stage compressor 1 is controlled to be turned on, and the third throttle valve 14 is controlled to be closed and the first throttle valve 12 and the second throttle valve 13 are controlled to be turned on.

[0094] In this embodiment, when it is detected that the ambient temperature is lower than the first set temperature but higher than the second set temperature, the control system automatically switches to the second heating mode. In this mode, the high-pressure stage compressor 2 still remains closed, and only the low-pressure stage compressor 1 undertakes the main work of the heat pump cycle. The purpose of this is to save energy and simplify the operation process without the need for two-stage compression.

[0095] Compared with the first heating mode, in this mode, the low-pressure stage compressor 1 turns on the function of gas replenishment and enthalpy increase. Gas replenishment and enthalpy increase can ensure sufficient heating efficiency even at a lower ambient temperature by increasing the refrigerant circulation volume and raising the enthalpy value of the refrigerant. The realization of gas replenishment and enthalpy increase depends on specific control strategies and valve adjustments.

[0096] Among them, in order to achieve air replenishment and enthalpy increase, the first throttle valve 12 and the second throttle valve 13 are opened at the same time, while the third throttle valve 14 remains closed. The first throttle valve 12 adjusts the refrigerant flow rate of the main circuit to ensure the normal intake of the low-pressure stage compressor 1. After the second throttle valve 13 is opened, part of the refrigerant after the condenser is allowed to be throttled and mixed with the exhaust gas of the low-pressure stage compressor 1, and replenished into the low-pressure stage compressor 1 to achieve the purpose of enthalpy increase. The closure of the third throttle valve 14 means that the air replenishment operation of the second branch 10 is not performed, because at this time it is only necessary to increase the heating efficiency of the low-pressure stage compressor 1 by air replenishment and enthalpy increase.

[0097] In this way, when facing a medium to low temperature environment, the heat pump system of the present invention can flexibly adjust to a suitable operating mode through precise temperature sensing and intelligent control strategies, which not only ensures efficient heating of the system but also avoids excessive energy consumption, reflecting its design concept of optimizing energy efficiency ratio and improving user experience under different working conditions.

[0098] Further, the step of controlling and adjusting the working parameters of the low-pressure stage compressor 1 and / or the high-pressure stage compressor 2 according to the actual outlet water temperature specifically includes: In the first heating mode or the second heating mode, the operating frequency of the low-pressure stage compressor 1 is controlled and adjusted according to the comparison result of the actual outlet water temperature and the target outlet water temperature so that the actual outlet water temperature is maintained at the target outlet water temperature.

[0099] The specific working process of the above-mentioned adjustment of the compressor frequency is as follows: The water temperature sensor (Tw) integrated in the system continuously monitors the temperature of the heat pump outlet water and compares it with the preset target water temperature (Tw0) in real time. The target water temperature is usually set according to user needs or system design standards to ensure the comfort and efficiency of heating or domestic hot water supply.

[0100] If the actual water outlet temperature (Tw) deviates from the target water temperature (Tw0) and exceeds the set allowable range (such as ±△T, recommended to be 1 to 2°C), the system will trigger the adjustment mechanism.

[0101] Once the deviation is identified, the control system will adjust the operating frequency (f1) of the low-pressure compressor 1 according to the deviation size and direction (high or low). If the actual outlet water temperature is lower than the target temperature, indicating insufficient heating, the system will appropriately increase the frequency of the low-pressure compressor 1, speed up the refrigerant circulation speed, and increase the heating capacity; conversely, if the actual outlet water temperature is higher than the target temperature, the compressor frequency will be reduced, the circulation speed will be slowed down, and the heating capacity will be reduced to maintain the stability of the outlet water temperature.

[0102] This adjustment process is continuous and dynamic. The system will periodically repeat the monitoring and comparison process to ensure that the actual outlet water temperature always remains near the target temperature. By making high-frequency fine-tuning instead of large-scale on-off control, not only the accuracy of temperature control is improved, but also the smooth operation of the system and the economy of energy use are guaranteed.

[0103] For example, assume that at a certain low ambient temperature, the system is in the second heating mode (the low-pressure stage compressor 1 operates alone and the enthalpy-increasing function is turned on), the target outlet water temperature is set at 50 °C, and the allowable deviation range is ±1 °C. The currently actually monitored outlet water temperature is 48.5 °C, which is 1.5 °C lower than the target value. The system then automatically adjusts the operating frequency of the low-pressure stage compressor 1, moderately increases the frequency f1, so that the refrigerant circulation accelerates, the refrigerant carries more heat, until the actual outlet water temperature rises back near the target temperature, such as 49.8 °C, and continues to be finely tuned and maintained stable in subsequent cycles.

[0104] In this way, through this refined temperature control mechanism, the present invention not only improves the heating efficiency and stability of the heat pump system, but also optimizes the user experience, ensuring efficient and reliable heat energy supply under different environments and working conditions.

[0105] In some specific embodiments, after the step of controlling and adjusting the operating parameters of the low-pressure stage compressor 1 and / or the high-pressure stage compressor 2 according to the actual outlet water temperature, it further includes: In the first heating mode, after the actual outlet water temperature is less than or equal to the target outlet water temperature and lasts for at least the first set duration, control the second throttle valve 13 to open, so that the heat pump system switches to the second heating mode.

[0106] It can be understood that the working principle of the above embodiments is as follows: When the system is operating in the first heating mode, that is, the low-pressure stage compressor 1 works alone but the enthalpy-increasing function is not turned on, the system continuously monitors the difference between the actual outlet water temperature (Tw) and the target outlet water temperature (Tw0). If it is found that the actual outlet water temperature is lower than or equal to the target temperature, and this situation lasts for the preset first set duration (such as more than 5 minutes), this usually indicates that the current heating capacity is insufficient to meet the demand, especially in the case of relatively low ambient temperature.

[0107] At this time, the system will take measures to control the second throttle valve 13 to open. The opening of the second throttle valve 13 means introducing the air-increasing enthalpy mechanism, that is, part of the refrigerant after the condenser passes through the throttle and is mixed with the exhaust gas of the low-pressure stage compressor 1 and replenished into the low-pressure stage compressor 1. This process increases the mass flow rate of the refrigerant inhaled by the low-pressure stage compressor 1 and increases the enthalpy value of the refrigerant, thereby improving the heating efficiency of the system without increasing the burden on the high-pressure stage compressor 2.

[0108] With the opening of the second throttle valve 13, the system actually automatically transitions from the first heating mode that relies only on the operation of the low-pressure compressor 1 to the second heating mode in which the low-pressure compressor 1 starts the enthalpy increase function. This conversion mechanism ensures that when the ambient temperature gradually decreases or the heat load demand increases, the heat pump system can adjust the operation strategy in time to maintain a stable heating effect and water temperature, improve the flexibility and adaptability of the system, and optimize the energy efficiency performance to ensure user comfort.

[0109] In some other specific embodiments, after the step of controlling and adjusting the working parameters of the low-pressure stage compressor 1 and / or the high-pressure stage compressor 2 according to the actual outlet water temperature, the method further includes: In the second heating mode, after the actual outlet water temperature is less than or equal to the target outlet water temperature and lasts for at least the second set time, the high-pressure compressor 2 is controlled to open and the third throttle valve 14 is controlled to open, so that the heat pump system switches to the fourth heating mode.

[0110] Among them, the fourth heating mode is a heating mode in which the two-stage compressors are running simultaneously and the low-pressure stage compressor 1 is turned on to increase enthalpy.

[0111] It can be understood that the working principle of the above embodiment is as follows: when the system is in the second heating mode, that is, the low-pressure stage compressor 1 is running alone and the enthalpy increase function is turned on, if it is detected that the actual water outlet temperature still cannot reach or remain above the target temperature, and this state below the target temperature continues for at least the second set time (this set time may be longer than the first set time to confirm that a higher level of heating capacity is indeed required), the system will take more powerful measures to improve the heating efficiency.

[0112] Specifically, the control system will start the high-pressure compressor 2 and open the third throttle valve 14 at the same time. This action marks the transition of the system from the second heating mode to the fourth heating mode, that is, the two-stage compressors are running at the same time, and the low-pressure compressor 1 still maintains the enthalpy increase operation state. In the fourth heating mode, the refrigerant not only undergoes the initial compression of the low-pressure compressor 1, but also undergoes the secondary compression of the high-pressure compressor 2, which significantly enhances the enthalpy value of the refrigerant and the heating capacity of the system, especially suitable for extremely low ambient temperatures, and can effectively solve the problem of insufficient heating capacity.

[0113] By opening the third throttle valve 14, part of the refrigerant is further cooled and depressurized by the second economizer 7 before being fed into the low-pressure compressor 1. This process of adding air and increasing enthalpy, combined with two-stage compression, not only improves the circulation efficiency of the refrigerant, but also ensures that the suction temperature of the high-pressure compressor 2 will not be too high, thereby ensuring the stable and efficient operation of the entire system. This control strategy demonstrates the ability of the heat pump system to flexibly adjust according to external environmental conditions and system operating conditions to achieve the best heating effect and energy efficiency ratio, providing users with a reliable and comfortable heat source supply.

[0114] In yet another embodiment of the present invention, the step of controlling and adjusting the operating mode of the heat pump system according to the ambient temperature specifically includes: When the ambient temperature is lower than the second set temperature, control and adjust the heat pump system to enter the third heating mode in which the two-stage compressor operates simultaneously and the low-pressure stage compressor 1 does not turn on the enthalpy-increasing function.

[0115] Wherein, in the third heating mode, control the high-pressure stage compressor 2 and the low-pressure stage compressor 1 to be both turned on, control the first throttle valve 12 and the third throttle valve 14 to be turned on and the second throttle valve 13 to be turned off.

[0116] In this embodiment, in the third heating mode, the system turns on the high-pressure stage compressor 2 and the low-pressure stage compressor 1 simultaneously, and uses the synergistic effect of two-stage compression to confront the heating challenge in an extremely low-temperature environment. In this mode, after the refrigerant is preliminarily compressed in the low-pressure stage compressor 1, it then enters the high-pressure stage compressor 2 for secondary compression, significantly increasing the temperature and pressure of the refrigerant, so that sufficient heating capacity can be generated even at a lower evaporation temperature.

[0117] Wherein, in order to adapt to the operation of two-stage compression, the first throttle valve 12 and the third throttle valve 14 are turned on, while the second throttle valve 13 is turned off. The function of the first throttle valve 12 is to adjust the high-pressure medium-temperature liquid of the main-circuit refrigerant after passing through the condenser, so that it cools down after passing through the economizer 1, preparing for the subsequent two-stage compression. The opening of the third throttle valve 14 is to introduce part of the refrigerant processed by the economizer 1 into the low-pressure stage compressor 1 to achieve refrigerant gas injection. However, in the third heating mode, the low-pressure stage compressor 1 does not turn on the enthalpy-increasing function, aiming to concentrate efforts on improving the heating capacity through two-stage compression.

[0118] The design of this mode aims to cope with extremely low-temperature environments, directly enhancing the heating capacity of the system under low-temperature conditions through two-stage compression without overly relying on enthalpy-increasing technology. This can not only ensure sufficient heating capacity but also optimize the energy efficiency ratio of the system. At the same time, by precisely controlling the opening and closing of the valves, the efficient circulation of the refrigerant in the system is ensured, reducing energy loss and improving the reliability and energy efficiency of the entire system.

[0119] Furthermore, the step of controlling and adjusting the operating parameters of the low-pressure stage compressor 1 and / or the high-pressure stage compressor 2 according to the actual water outlet temperature specifically includes: In the third heating mode, according to the comparison result between the actual water outlet temperature and the target water outlet temperature, control and adjust the operating frequencies of the high-pressure stage compressor 2 and the low-pressure stage compressor 1 so that the actual water outlet temperature remains at the target water outlet temperature.

[0120] In this embodiment, when the deviation between the actual outlet water temperature and the target outlet water temperature exceeds a predetermined range (e.g., ±1°C), the control system responds immediately. If the actual outlet water temperature is lower than the target value, indicating insufficient heating, the control system will appropriately increase the operating frequencies (f1, f2) of the high-pressure stage compressor 2 and the low-pressure stage compressor 1, accelerate the refrigerant circulation rate, enhance the heating effect, and increase the outlet water temperature; conversely, if the actual outlet water temperature is higher than the target value, indicating excessive heating capacity, the system will correspondingly reduce the operating frequency of the compressor, slow down the refrigerant circulation speed, reduce the heating capacity, and lower the outlet water temperature to keep it within the target range.

[0121] Through this precise temperature control logic, the present invention not only enhances the adaptability and reliability of the heat pump system under extreme conditions, but also improves the user experience and ensures the efficient and energy-saving operation of the system during the annual heating season.

[0122] Further, after the step of controlling and adjusting the operating parameters of the low-pressure stage compressor 1 and / or the high-pressure stage compressor 2 according to the actual outlet water temperature, the following is also included: In the third heating mode, after the actual outlet water temperature is less than or equal to the target outlet water temperature and lasts for at least the third set duration, control the second throttle valve 13 to open so that the heat pump system switches to the fourth heating mode.

[0123] Among them, the fourth heating mode is a heating mode in which the two-stage compressor operates simultaneously and the low-pressure stage compressor 1 turns on the enthalpy increase.

[0124] Specifically, when the system is operating in the third heating mode (the two-stage compressor operates simultaneously, but the low-pressure stage compressor 1 does not turn on the enthalpy increase), if it is monitored that the actual outlet water temperature fails to reach or continuously remains lower than the target outlet water temperature, and this state lasts for at least the third set duration, the system will take further adjustment measures.

[0125] The system will control the second throttle valve 13 to open, and this operation marks the conversion of the heat pump system from the third heating mode to the fourth heating mode. In the fourth heating mode, not only does the two-stage compressor continue to work simultaneously to cope with the low-temperature environment, but the low-pressure stage compressor 1 also starts to implement the enthalpy increase operation. During the enthalpy increase process, by supplementing gas, the density and enthalpy value of the refrigerant are increased, further enhancing the heating capacity of the system in the extremely low-temperature environment, ensuring that the outlet water temperature can be effectively increased under harsh conditions, and meeting the user's demand for heat energy.

[0126] Through this dynamic response mechanism, when the heat pump system detects that the actual performance does not match the target performance, it can automatically adjust the operating strategy, changing from the two-stage non-enthalpy-increase mode to the two-stage enthalpy-increase mode. This transformation not only reflects the flexibility of the system design, but also ensures that the heat pump can continue to operate efficiently under the complex and changeable external environment, achieve the established heating goal, and maintain the optimization of energy efficiency.

[0127] As Figure 4 shown, the control device of the heat pump system according to the embodiment of the third aspect of the present invention includes: A first acquisition module 110, configured to acquire the ambient temperature of the environment where the heat pump system is located; A first control module 120, configured to control and adjust the working mode of the heat pump system according to the ambient temperature; A second acquisition module 130, configured to acquire the actual water outlet temperature of the heat pump system in the current working mode; A second control module 140, configured to control and adjust the working parameters of the low-pressure stage compressor 1 and / or the high-pressure stage compressor 2 according to the actual water outlet temperature.

[0128] Wherein, in different working modes, the opening and closing conditions of the first throttle valve 12, the second throttle valve 13, and the third throttle valve 14 are different.

[0129] Figure 5 Illustrates a schematic diagram of the physical structure of an electronic device. As Figure 5 shown, the electronic device may include: a processor 810, a communication interface 820, a memory 830, and a communication bus 840. Among them, the processor 810, the communication interface 820, and the memory 830 complete mutual communication through the communication bus 840. The processor 810 can call the logic instructions in the memory 830 to execute the control method of the heat pump system, including: acquiring the ambient temperature of the environment where the heat pump system is located; controlling and adjusting the working mode of the heat pump system according to the ambient temperature; acquiring the actual water outlet temperature of the heat pump system in the current working mode; controlling and adjusting the working parameters of the low-pressure stage compressor 1 and / or the high-pressure stage compressor 2 according to the actual water outlet temperature; wherein, in different working modes, the opening and closing conditions of the first throttle valve 12, the second throttle valve 13, and the third throttle valve 14 are different.

[0130] In addition, when the logical instructions in the above-mentioned memory 830 are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or a part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods according to the various embodiments of the present invention. The aforementioned storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memories (ROM, Read-Only Memory), random access memories (RAM, Random Access Memory), magnetic disks, or optical discs that can store program codes.

[0131] On the other hand, the present invention also provides a computer program product. The computer program product includes a computer program that can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the control method of the heat pump system provided by the above-mentioned various methods, including: obtaining the ambient temperature of the environment where the heat pump system is located; controlling and adjusting the working mode of the heat pump system according to the ambient temperature; in the current working mode, obtaining the actual water outlet temperature of the heat pump system; controlling and adjusting the working parameters of the low-pressure stage compressor 1 and / or the high-pressure stage compressor 2 according to the actual water outlet temperature; wherein, in different working modes, the opening and closing conditions of the first throttle valve 12, the second throttle valve 13, and the third throttle valve 14 are different.

[0132] In yet another aspect, the present invention also provides a non-transitory computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, it is implemented to execute the control method of the heat pump system provided by the above-mentioned various methods, including: obtaining the ambient temperature of the environment where the heat pump system is located; controlling and adjusting the working mode of the heat pump system according to the ambient temperature; in the current working mode, obtaining the actual water outlet temperature of the heat pump system; controlling and adjusting the working parameters of the low-pressure stage compressor 1 and / or the high-pressure stage compressor 2 according to the actual water outlet temperature; wherein, in different working modes, the opening and closing conditions of the first throttle valve 12, the second throttle valve 13, and the third throttle valve 14 are different.

[0133] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art can understand and implement it without creative efforts.

[0134] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on such an understanding, the essence of the above technical solution, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods of each embodiment or some parts of the embodiments.

[0135] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of each embodiment of the present invention.

Claims

1. A heat pump system, characterized in that, It includes a high-pressure stage compressor, a low-pressure stage compressor, an air-side heat exchanger, a first throttle valve, and a water-side heat exchanger connected through a main refrigerant circuit; The air-side heat exchanger is connected to the suction port of the low-pressure stage compressor, the discharge port of the low-pressure stage compressor is connected to the suction port of the high-pressure stage compressor, the discharge port of the high-pressure stage compressor is connected to the water-side heat exchanger, and a first economizer and a second economizer are arranged between the water-side heat exchanger and the air-side heat exchanger; Wherein, a first branch parallel to the main refrigerant circuit is provided between the water-side heat exchanger and the first economizer, the first branch flows through the first economizer and is connected to the suction port of the high-pressure stage compressor; a second branch parallel to the main refrigerant circuit is provided between the first economizer and the second economizer, the second branch flows through the second economizer and is connected to the gas supplement port of the low-pressure stage compressor; and a second throttle valve is provided on the first branch, and a third throttle valve is provided on the second branch.

2. The heat pump system according to claim 1, characterized in that, It further includes: An ambient temperature sensor and a water outlet temperature sensor; A control device, connected to the ambient temperature sensor and the water outlet temperature sensor, for obtaining the ambient temperature and the water outlet temperature, and controlling and adjusting the working mode and its working parameters of the heat pump system according to the ambient temperature and the water outlet temperature; Preferably, a third branch is connected in parallel on both sides of the high-pressure stage compressor, a check valve is provided on the third branch, and the valve direction of the check valve is oriented along the direction from the suction port to the discharge port of the high-pressure stage compressor.

3. A control method for a heat pump system according to any one of claims 1 to 2, characterized in that, It includes: Obtaining the ambient temperature of the environment where the heat pump system is located; Controlling and adjusting the working mode of the heat pump system according to the ambient temperature; Under the current working mode, obtaining the actual water outlet temperature of the heat pump system; Controlling and adjusting the working parameters of the low-pressure stage compressor and / or the high-pressure stage compressor according to the actual water outlet temperature; wherein, under different working modes, the opening and closing conditions of the first throttle valve, the second throttle valve, and the third throttle valve are different.

4. The control method of the heat pump system according to claim 3, wherein The step of controlling and adjusting the working mode of the heat pump system according to the ambient temperature specifically includes: When the ambient temperature is greater than or equal to a first set temperature, controlling and adjusting the heat pump system to enter a first heating mode in which the low-pressure stage compressor operates alone without increasing enthalpy; Wherein, in the first heating mode, controlling the high-pressure stage compressor to be closed and the low-pressure stage compressor to be opened, and controlling the second throttle valve and the third throttle valve to be closed and the first throttle valve to be opened; Or, when the ambient temperature is less than the first set temperature and greater than a second set temperature, controlling and adjusting the heat pump system to enter a second heating mode in which the low-pressure stage compressor operates alone with increasing enthalpy; Wherein, in the second heating mode, controlling the high-pressure stage compressor to be closed and the low-pressure stage compressor to be opened, and controlling the third throttle valve to be closed and the first throttle valve and the second throttle valve to be opened.

5. The control method of the heat pump system according to claim 4, characterized in that The step of controlling and adjusting the working parameters of the low-pressure stage compressor and / or the high-pressure stage compressor according to the actual water outlet temperature specifically includes: In the first heating mode or the second heating mode, according to the comparison result between the actual water outlet temperature and the target water outlet temperature, control and adjust the operating frequency of the low-pressure stage compressor so that the actual water outlet temperature is maintained at the target water outlet temperature.

6. The control method of the heat pump system according to claim 5, characterized in that, After the step of controlling and adjusting the operating parameters of the low-pressure stage compressor and / or the high-pressure stage compressor according to the actual water outlet temperature, it further includes: in the first heating mode, after the actual water outlet temperature is less than or equal to the target water outlet temperature and lasts for at least a first set duration, control the second throttle valve to open so that the heat pump system switches to the second heating mode; Alternatively, in the second heating mode, after the actual water outlet temperature is less than or equal to the target water outlet temperature and lasts for at least a second set duration, control the high-pressure stage compressor to start and the third throttle valve to open so that the heat pump system switches to the fourth heating mode; Wherein, the fourth heating mode is a heating mode in which the two-stage compressor operates simultaneously and the low-pressure stage compressor enables enthalpy increase.

7. The control method of the heat pump system according to claim 3, characterized in that The step of controlling and adjusting the operating mode of the heat pump system according to the ambient temperature specifically includes: When the ambient temperature is less than the second set temperature, control and adjust the heat pump system to enter the third heating mode in which the two-stage compressor operates simultaneously and the low-pressure stage compressor does not enable enthalpy increase; Wherein, in the third heating mode, control both the high-pressure stage compressor and the low-pressure stage compressor to start, control the first throttle valve and the third throttle valve to open and the second throttle valve to close.

8. The control method of the heat pump system according to claim 7, wherein The step of controlling and adjusting the operating parameters of the low-pressure stage compressor and / or the high-pressure stage compressor according to the actual water outlet temperature specifically includes: In the third heating mode, according to the comparison result between the actual water outlet temperature and the target water outlet temperature, control and adjust the operating frequencies of the high-pressure stage compressor and the low-pressure stage compressor so that the actual water outlet temperature is maintained at the target water outlet temperature.

9. The control method of the heat pump system according to claim 8, wherein After the step of controlling and adjusting the operating parameters of the low-pressure stage compressor and / or the high-pressure stage compressor according to the actual water outlet temperature, it further includes: in the third heating mode, after the actual water outlet temperature is less than or equal to the target water outlet temperature and lasts for at least a third set duration, control the second throttle valve to open so that the heat pump system switches to the fourth heating mode; Wherein, the fourth heating mode is a heating mode in which the two-stage compressor operates simultaneously and the low-pressure stage compressor enables enthalpy increase.

10. A control device for a heat pump system according to any one of claims 1 to 2, characterized in that, It includes: A first acquisition module for acquiring the ambient temperature of the environment where the heat pump system is located; A first control module for controlling and adjusting the operating mode of the heat pump system according to the ambient temperature; A second acquisition module for acquiring the actual water outlet temperature of the heat pump system in the current operating mode; A second control module for controlling and adjusting the operating parameters of the low-pressure stage compressor and / or the high-pressure stage compressor according to the actual water outlet temperature; Wherein, in different operating modes, the opening and closing conditions of the first throttle valve, the second throttle valve and the third throttle valve are different.

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