Air conditioner heat pump unit shutdown control method and air conditioner heat pump unit

Abstract

The invention belongs to the technical field of air conditioners, and discloses a control method for shutdown of an air conditioner heat pump unit and the air conditioner heat pump unit. The control method for shutdown of the air conditioner heat pump unit comprises the steps that S1, the air conditioner heat pump unit comprises a compressor, and when a shutdown instruction or a mode switching instruction is received, the operation frequency of the compressor is reduced to the minimum operation frequency fmin, continuously running for a first time t1; s2, the air conditioner heat pump unit further comprises a reversing four-way valve, and the reversing four-way valve is controlled to reverse for a second time t2; and S3, the compressor is controlled to stop. By reducing the frequency of the compressor, 'pressure oscillation 'caused by the fact that refrigerants on the high-pressure side rapidly flow back to the low-pressure side due to sudden shutdown and impact on a reversing four-way valve during reversing are avoided, abnormal noise and vibration during shutdown are improved, the differential pressure balance speed is increased through reversing, the time for waiting for restarting is shortened, and the service life of the compressor is prolonged. And the use experience of the user is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioning, and in particular to a shutdown control method for an air conditioning heat pump unit and the air conditioning heat pump unit. Background Art

[0002] The heat pump unit is the core equipment of the air-conditioning system for both cooling and heating. Based on the principle of the reverse Carnot cycle, it regulates the indoor temperature by consuming a small amount of electricity to transport heat, and has the characteristics of high efficiency, energy saving, and two-way temperature control. In cooling mode, the compressor compresses the gaseous refrigerant, which then releases heat and liquefies in the condenser. The liquid refrigerant, which has been reduced in pressure and temperature by the expansion valve, absorbs heat and vaporizes in the evaporator. The vaporized refrigerant is then sucked into the compressor for circulation. The heating mode is achieved by changing the flow direction of the refrigerant through a four-way reversing valve. The heat pump unit is generally composed of components such as a compressor, condenser, evaporator, expansion valve, four-way reversing valve, refrigerant, and an electronic control system. These components work together to achieve temperature regulation of the indoor environment with low energy consumption. It is widely used in residential and commercial buildings.

[0003] However, when the air conditioner receives a shutdown command or a mode switching command, the compressor will shut down. However, due to the large pressure difference between the high and low pressures on both sides of the compressor, the compressor will produce obvious abnormal noise or vibration after shutdown. When restarting the compressor, it is necessary to wait for the pressure difference to be balanced by default before restarting. The waiting time for the natural pressure difference to be balanced is long, which results in a long waiting time for restart, resulting in a poor user experience.

[0004] Therefore, there is an urgent need for a control method for stopping an air-conditioning heat pump unit and an air-conditioning heat pump unit to solve the above problems. Summary of the Invention

[0005] The purpose of the present invention is to provide a control method for the shutdown of an air-conditioning heat pump unit and an air-conditioning heat pump unit, which improves the abnormal noise and vibration of the compressor during shutdown, accelerates the speed of pressure difference balance, shortens the waiting time for restart, and improves the user experience.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] On the one hand, a method for controlling the shutdown of an air-conditioning heat pump unit is provided. The method for controlling the shutdown of an air-conditioning heat pump unit is used to control the air-conditioning heat pump unit when the air conditioner receives a mode switching instruction or a shutdown instruction. The method for controlling the shutdown of the air-conditioning heat pump unit includes the following steps:

[0008] S1. The air conditioning heat pump unit includes a compressor. When receiving the shutdown command or the mode switching command, the operating frequency of the compressor is reduced to the minimum operating frequency f min , and continue to run for the first time t1;

[0009] S2, the air conditioning heat pump unit further includes a reversing four-way valve, controlling the reversing of the reversing four-way valve and lasting for a second time t2;

[0010] S3. Control the compressor to stop.

[0011] Optionally, in step S3, the following steps are further included:

[0012] S31, controlling the compressor to stop;

[0013] S32: The air conditioning heat pump unit further includes an electronic expansion valve, and the opening X of the electronic expansion valve is adjusted so that X ≥ 300 steps is satisfied;

[0014] S33: The air-conditioning heat pump unit further includes a fan, and the fan is made to continue to run for a third time t3 after the compressor stops, and then the fan is turned off.

[0015] Optionally, the third time t3 satisfies t3≥30s.

[0016] Optionally, the minimum operating frequency f of the compressor min , satisfying f min ≤30Hz.

[0017] Optionally, the first time t1 satisfies t1≥10s.

[0018] Optionally, the second time t2 satisfies t2≥10s.

[0019] Optionally, the air-conditioning heat pump unit further includes a first pressure detector and a second pressure detector, the first pressure detector being used to detect a first pressure P1 on the exhaust side of the compressor, and the second pressure detector being used to detect a second pressure P2 on the suction side of the compressor, the first pressure P1 and the second pressure P2 satisfying P1-P2≤0.2MPa.

[0020] On the other hand, an air-conditioning heat pump unit is provided, which executes the shutdown instruction or the mode switching instruction using the air-conditioning heat pump unit shutdown control method as described in any one of the above items.

[0021] Optionally, the air-conditioning heat pump unit also includes a first heat exchanger, a second heat exchanger, an electronic expansion valve and a gas-liquid separator, the reversing four-way valve is used to connect the exhaust side of the compressor with the inlet of the first heat exchanger and the suction side of the compressor with the outlet of the second heat exchanger, or the reversing four-way valve is used to connect the suction side of the compressor with the outlet of the first heat exchanger and the exhaust side of the compressor with the inlet of the second heat exchanger, the electronic expansion valve is connected between the first heat exchanger and the second heat exchanger, and the gas-liquid separator is arranged on the suction side of the compressor.

[0022] Optionally, the air-conditioning heat pump unit further includes a liquid reservoir connected between the electronic expansion valve and the second heat exchanger.

[0023] Beneficial effects of the present invention:

[0024] The present invention provides a control method for stopping an air-conditioning heat pump unit. When the compressor is stopped, the control method first reduces the operating frequency of the compressor to a minimum operating frequency in step S1. After running for a first time, the reversing four-way valve is used for reversing in step S2 and the reversing is continued for a second time. The reducing the operating frequency of the compressor in step S1 reduces the speed of the compressor and the circulation amount of the refrigerant, thereby gradually reducing the pressure difference between the high-pressure and low-pressure sides, thereby avoiding the rapid backflow of the high-pressure side refrigerant to the low-pressure side due to sudden shutdown, thereby preventing "pressure oscillation" caused by the sudden shutdown. On the other hand, since part of the system pressure has been balanced by frequency reduction, the residual pressure difference on the high-pressure side is low, thereby reducing the impact of the reversing four-way valve during reversing in step S2, thereby improving abnormal noise and vibration of the compressor during shutdown. In addition, the reversing four-way valve is used for reversing in step S2. On the one hand, a temporary pressure connection is achieved during the reversing, and on the other hand, the high and low pressure sides are swapped after the reversing. In this way, the pressure difference between the high and low pressure sides is actively intervened, the speed of pressure differential balancing is accelerated, the waiting time for restart is shortened, and the user experience is improved.

[0025] The present invention also provides an air-conditioning heat pump unit, which, by applying the above-mentioned control method, improves the abnormal noise and vibration of the compressor during shutdown when executing a shutdown command or a mode switching command, accelerates the speed of pressure difference balance, shortens the waiting time for restart, and improves the user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a flowchart of the steps of the control method for stopping the air-conditioning heat pump unit provided by the present invention;

[0027] Figure 2 This is a system principle diagram of the air-conditioning heat pump unit provided by the present invention.

[0028] In the picture:

[0029] 1. Compressor; 2. Reversing four-way valve; 3. Electronic expansion valve; 4. Fan; 5. First pressure detector; 6. Second pressure detector; 7. First heat exchanger; 8. Second heat exchanger; 9. Gas-liquid separator; 10. Liquid reservoir. DETAILED DESCRIPTION

[0030] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It will be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all structures.

[0031] In the description of the present invention, unless otherwise expressly specified or limited, the terms "connected," "connected," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention in specific circumstances.

[0032] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0033] In the description of this embodiment, the terms "upper," "lower," "right," and other orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely for ease of description and simplified operation. They do not indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are used solely for descriptive purposes and have no special meanings.

[0034] The heat pump unit is the core equipment of the air-conditioning system for both cooling and heating. Based on the principle of the reverse Carnot cycle, it regulates the indoor temperature by consuming a small amount of electricity to transport heat, and has the characteristics of high efficiency, energy saving, and two-way temperature control. In cooling mode, the compressor compresses the gaseous refrigerant, which then releases heat and liquefies in the condenser. The liquid refrigerant, which has been reduced in pressure and temperature by the expansion valve, absorbs heat and vaporizes in the evaporator. The vaporized refrigerant is then sucked into the compressor for circulation. The heating mode is achieved by changing the flow direction of the refrigerant through a four-way reversing valve. The heat pump unit is generally composed of components such as a compressor, condenser, evaporator, expansion valve, four-way reversing valve, refrigerant, and an electronic control system. These components work together to achieve temperature regulation of the indoor environment with low energy consumption. It is widely used in residential and commercial buildings.

[0035] However, when the air conditioner receives a shutdown command or a mode switching command, the compressor will shut down. However, due to the large pressure difference between the high and low pressures on both sides of the compressor, the compressor will produce obvious abnormal noise or vibration after shutdown. When restarting the compressor, it is necessary to wait for the pressure difference to be balanced by default before restarting. The waiting time for the natural pressure difference to be balanced is long, which results in a long waiting time for restart, resulting in a poor user experience.

[0036] Therefore, in order to improve the abnormal noise and vibration of the compressor when it is shut down, accelerate the speed of pressure difference balance, shorten the waiting time for restart, and improve the user experience, this embodiment provides a control method for the shutdown of an air-conditioning heat pump unit. The control method for the shutdown of an air-conditioning heat pump unit is used to control the air-conditioning heat pump unit when the air conditioner receives a mode switching instruction or a shutdown instruction.

[0037] like Figures 1 to 2 As shown, the control method for stopping the air-conditioning heat pump unit includes the following steps:

[0038] S1. The air conditioning heat pump unit includes a compressor 1. When receiving a shutdown command or a mode switching command, the operating frequency of the compressor 1 is reduced to the minimum operating frequency f min , and continue to run for the first time t1;

[0039] S2, the air conditioning heat pump unit further includes a reversing four-way valve 2, which controls the reversing of the reversing four-way valve 2 and lasts for a second time t2;

[0040] S3. Control compressor 1 to stop.

[0041] When the compressor 1 is stopped by the control method, the operating frequency of the compressor 1 is first reduced to the minimum operating frequency in step S1. After running for a first time, the reversing four-way valve 2 is used to perform reversing in step S2 and the reversing is continued for a second time. The reduction of the operating frequency of the compressor 1 in step S1, on the one hand, reduces the speed of the compressor 1 and reduces the circulation amount of the refrigerant, thereby gradually reducing the pressure difference between the high-pressure and low-pressure sides, avoiding the rapid backflow of the high-pressure side refrigerant to the low-pressure side due to sudden shutdown, causing "pressure shock". On the other hand, since part of the system pressure has been balanced by frequency reduction, the residual pressure difference on the high-pressure side is low, reducing the impact of the reversing four-way valve 2 during reversing in step S2, thereby improving the abnormal noise and vibration of the compressor 1 during shutdown. In addition, the reversing of the four-way valve 2 in step S2, on the one hand, achieves a brief pressure connection during reversing, and on the other hand, achieves the role exchange of the high and low pressure sides after reversing, thereby actively intervening in the pressure difference between the high and low pressure sides, accelerating the speed of pressure differential balancing, shortening the waiting time for restart, and improving the user experience.

[0042] Optionally, in step S3, the following steps are further included:

[0043] S31, controlling compressor 1 to stop;

[0044] S32, the air conditioning heat pump unit further includes an electronic expansion valve 3, and the opening X of the electronic expansion valve 3 is adjusted to satisfy X ≥ 300 steps;

[0045] S33: The air conditioning heat pump unit further includes a fan 4. The fan 4 is operated for a third time t3 after the compressor 1 is shut down, and then the fan 4 is turned off.

[0046] Since the refrigerant is still in a flowing state after the compressor 1 is shut down, step S32 is used to increase the opening of the electronic expansion valve 3 to avoid the impact of the refrigerant on the electronic expansion valve 3, further reduce noise and protect the electronic expansion valve 3; and after the compressor 1 is shut down, some refrigerant heat still remains in the heat pump unit (such as when the heating is shut down, the indoor condenser temperature is high). At this time, step S33 is used to blow this heat into the room by continuing to run the fan 4, avoiding energy waste. It is particularly suitable for "waste heat utilization" before the heating mode is shut down. On the other hand, after the compressor 1 is shut down, the temperature distribution of the components in the heat pump unit is uneven (such as high temperature of the condenser and low temperature of the evaporator). The continuous operation of the fan 4 can reduce the temperature difference through air circulation, avoiding leakage of the pipeline interface or deformation of the components due to thermal expansion and contraction.

[0047] Optionally, the third time t3 satisfies t3≥30s. By limiting the third time t3 to satisfy t3≥30s, the running time of the fan 4 is ensured, thereby preventing the fan 4 from running too short after the compressor 1 stops, resulting in failure to achieve the expected effect.

[0048] Optionally, the minimum operating frequency f of the compressor 1 min , satisfying f min ≤30Hz. By adjusting the minimum operating frequency f of compressor 1 min Restrict it to satisfy f min ≤30Hz, which changes the shutdown process of compressor 1 from "hard interruption" to "soft transition". Its essence is to achieve noise control and improve pressure balance efficiency through the gradient attenuation of speed-load-pressure.

[0049] Optionally, the first time t1 satisfies t1 ≥ 10s. By limiting the first time t1 to satisfy t1 ≥ 10s, the compressor 1 is ensured to have sufficient time to operate at a low frequency, thereby minimizing the pressure difference between the high-pressure and low-pressure sides before reversing, thereby avoiding impact on the reversing four-way valve 2 during reversing, reducing vibration, and reducing noise.

[0050] Optionally, the second time t2 satisfies t2 ≥ 10s. By limiting the second time t2 to satisfy t2 ≥ 10s, sufficient time for switching is ensured, thereby ensuring that after the second time ends, the pressure difference between the high-pressure and low-pressure sides is reduced as much as possible, so that the pressure difference on both sides of the compressor 1 tends to be balanced, thereby shortening the waiting time when the compressor 1 is restarted and improving the user experience.

[0051] Optionally, the air conditioning heat pump unit further includes a first pressure detector 5 and a second pressure detector 6. The first pressure detector 5 is used to detect a first pressure P1 on the exhaust side of the compressor 1, and the second pressure detector 6 is used to detect a second pressure P2 on the suction side of the compressor 1. The first pressure P1 and the second pressure P2 satisfy P1-P2≤0.2MPa. By providing the first pressure detector 5 and the second pressure detector 6, the pressure values on the exhaust side and the suction side of the compressor 1 are measured, and the pressure difference between the two sides is limited to satisfy P1-P2≤0.2MPa, thereby avoiding a long waiting time when restarting due to an excessively large pressure difference.

[0052] In this embodiment, if Figure 2As shown, an air conditioning heat pump unit is also provided. The air conditioning heat pump unit uses the above-mentioned control method for air conditioning heat pump units to execute a shutdown command or a mode switching command. By applying the above-mentioned control method, the air conditioning heat pump unit can improve the abnormal noise and vibration of the compressor 1 during shutdown when executing the shutdown command or the mode switching command, accelerate the speed of pressure difference balance, shorten the waiting time for restart, and improve the user experience.

[0053] Optionally, the air conditioning heat pump unit further includes a first heat exchanger 7, a second heat exchanger 8, an electronic expansion valve 3 and a gas-liquid separator 9. The reversing four-way valve 2 is used to connect the exhaust side of the compressor 1 with the inlet of the first heat exchanger 7 and the suction side of the compressor 1 with the outlet of the second heat exchanger 8, or the reversing four-way valve 2 is used to connect the suction side of the compressor 1 with the outlet of the first heat exchanger 7 and the exhaust side of the compressor 1 with the inlet of the second heat exchanger 8. The electronic expansion valve 3 is connected between the first heat exchanger 7 and the second heat exchanger 8, and the gas-liquid separator 9 is provided on the suction side of the compressor 1. Due to the moment when the compressor 1 stops, the high-pressure gas on the exhaust side may flow back to the suction side through the valve plate gap, causing the suction pressure to rise suddenly. If liquid refrigerant exists in the system (e.g., refrigerant that has not been completely evaporated by the evaporator), the backflowing airflow may carry liquid droplets and quickly enter the suction port of the compressor 1. Therefore, a gas-liquid separator 9 is provided on the suction side of the compressor 1 as a "liquid buffer" on the suction side to store the migrated liquid refrigerant, thereby reducing the impact of the refrigerant on the compressor 1. In this embodiment, the first heat exchanger 7 is a fin heat exchanger, and the second heat exchanger 8 is a plate heat exchanger.

[0054] Optionally, the air conditioning heat pump unit further includes a liquid accumulator 10, which is connected between the electronic expansion valve 3 and the second heat exchanger 8. By providing the liquid accumulator 10, the liquid refrigerant that has not been completely evaporated is stored, thereby avoiding impact on the compressor 1, reducing abnormal noise generated by the impact, and enhancing protection for the compressor 1.

[0055] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention and are not intended to limit the embodiments of the present invention. A person skilled in the art would be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A method for controlling the shutdown of an air-conditioning heat pump unit, characterized in that: The air conditioner heat pump unit shutdown control method is used to control the air conditioner heat pump unit when the air conditioner receives a mode switching instruction or a shutdown instruction. The air conditioner heat pump unit shutdown control method includes the following steps: S1. The air-conditioning heat pump unit includes a compressor (1). When receiving the shutdown instruction or the mode switching instruction, the operating frequency of the compressor (1) is reduced to the minimum operating frequency f min , and continue to run for the first time t1; S2, the air conditioning heat pump unit further comprises a reversing four-way valve (2), which controls the reversing of the reversing four-way valve (2) and lasts for a second time t2; S3, controlling the compressor (1) to stop.

2. The method for controlling shutdown of an air-conditioning heat pump unit according to claim 1, characterized in that: In step S3, the following steps are also included: S31, controlling the compressor (1) to stop; S32, the air conditioning heat pump unit further includes an electronic expansion valve (3), and the opening X of the electronic expansion valve (3) is adjusted to satisfy X≥300 steps; S33: The air-conditioning heat pump unit further includes a fan (4), and the fan (4) is operated continuously for a third time t3 after the compressor (1) stops, and then the fan (4) is turned off.

3. The method for controlling shutdown of an air-conditioning heat pump unit according to claim 2, characterized in that: The third time t3 satisfies t3≥30s.

4. The method for controlling shutdown of an air-conditioning heat pump unit according to claim 1, characterized in that: The minimum operating frequency f of the compressor (1) min , satisfying f min ≤30Hz.

5. The method for controlling shutdown of an air-conditioning heat pump unit according to claim 1, characterized in that: The first time t1 satisfies t1≥10s.

6. The method for controlling shutdown of an air-conditioning heat pump unit according to claim 1, characterized in that: The second time t2 satisfies t2≥10s.

7. The method for controlling shutdown of an air-conditioning heat pump unit according to claim 1, characterized in that: The air-conditioning heat pump unit further comprises a first pressure detector (5) and a second pressure detector (6), wherein the first pressure detector (5) is used to detect a first pressure P1 on the exhaust side of the compressor (1), and the second pressure detector (6) is used to detect a second pressure P2 on the suction side of the compressor (1), wherein the first pressure P1 and the second pressure P2 satisfy P1-P2≤0.2MPa.

8. Air conditioning heat pump unit, characterized in that, The air conditioning heat pump unit executes the shutdown instruction or the mode switching instruction using the air conditioning heat pump unit shutdown control method according to any one of claims 1 to 7.

9. The air conditioning heat pump unit according to claim 8, characterized in that: The air-conditioning heat pump unit further comprises a first heat exchanger (7), a second heat exchanger (8), an electronic expansion valve (3) and a gas-liquid separator (9); the reversing four-way valve (2) is used to connect the exhaust side of the compressor (1) with the inlet of the first heat exchanger (7) and the intake side of the compressor (1) with the outlet of the second heat exchanger (8); or the reversing four-way valve (2) is used to connect the intake side of the compressor (1) with the outlet of the first heat exchanger (7) and the exhaust side of the compressor (1) with the inlet of the second heat exchanger (8); the electronic expansion valve (3) is connected between the first heat exchanger (7) and the second heat exchanger (8); and the gas-liquid separator (9) is provided on the intake side of the compressor (1).

10. The air conditioning heat pump unit according to claim 9, characterized in that: The air-conditioning heat pump unit further comprises a liquid reservoir (10), and the liquid reservoir (10) is connected between the electronic expansion valve (3) and the second heat exchanger (8).

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