Heating control method for air conditioner

Abstract

This invention relates to the field of air conditioning technology, specifically to a heating control method for an air conditioner. This application aims to solve the problem of how to meet the heating needs of two application scenarios: extreme cold and low temperature with high humidity. To this end, the air conditioner of this application has a variable capacity compressor with two compression cylinders. The air conditioner also includes a gas supply line, one end of which is connected to the refrigerant line between the throttling device and the outdoor heat exchanger inlet, and the other end is connected to the suction port of the variable capacity compressor. An adjustable valve is provided on the gas supply line. The heating control method includes: acquiring the outdoor ambient temperature; determining the operating mode of the variable capacity compressor based on the temperature range of the outdoor ambient temperature; during operation, determining the difference between the outdoor coil temperature and the dew point temperature corresponding to the outdoor ambient temperature; and based on the determination result, selectively performing defrosting or anti-frost operations. This air conditioner can be applied to multiple application scenarios simultaneously and can perform defrosting or anti-frost processing according to the frosting situation.

Description

Technical Field

[0001] This invention relates to the field of air conditioning technology, and more specifically to a heating control method for an air conditioner. Background Technology

[0002] my country has a vast territory with significant differences in climate across different regions. In the middle and lower reaches of the Yangtze River, the winter climate is characterized by low temperatures and high humidity, leading to severe frost buildup and frequent defrosting during air conditioning heating. This results in large fluctuations in room temperature, preventing the room from rising properly and causing a poor user experience. In contrast, the upper reaches of the Yangtze River are located in extremely cold regions with temperatures typically below -20°C in winter. This places higher demands on the reliability of the compressor, requiring it to handle high compression ratios for heating.

[0003] Accordingly, a new technical solution is needed in this field to solve the above problems. Summary of the Invention

[0004] To address at least one of the aforementioned problems in the prior art, namely, how to meet the heating requirements of both extremely cold and low-temperature, high-humidity application scenarios, this application provides a heating control method for an air conditioner. The air conditioner includes a variable-capacity compressor, an indoor heat exchanger, a throttling device, and an outdoor heat exchanger, connected sequentially via refrigerant piping. The variable-capacity compressor has two compression cylinders. The air conditioner also includes a gas supply piping, one end of which is connected to the refrigerant piping between the throttling device and the inlet of the outdoor heat exchanger, and the other end of which is connected to the suction port of the variable-capacity compressor. The gas supply piping is equipped with an adjustable valve. The heating control method includes:

[0005] Obtain the outdoor ambient temperature;

[0006] Based on the temperature range of the outdoor ambient temperature, the operating mode of the variable capacity compressor is determined, and the variable capacity compressor is controlled to operate according to the operating mode.

[0007] During operation, the outdoor coil temperature of the outdoor heat exchanger is obtained;

[0008] Determine the magnitude of the difference between the outdoor coil temperature and the dew point temperature corresponding to the outdoor ambient temperature;

[0009] Based on the judgment result, selectively perform defrosting or defrosting operations;

[0010] The variable capacity compressor operates in two modes: a dual-cylinder mode and a two-stage mode. In the dual-cylinder mode, the two compression cylinders of the variable capacity compressor compress the refrigerant individually. In the two-stage mode, the two compression cylinders of the variable capacity compressor compress the refrigerant sequentially.

[0011] In the preferred embodiment of the heating control method for the aforementioned air conditioner, the step of "determining the operating mode of the variable capacity compressor based on the temperature range of the outdoor ambient temperature" further includes:

[0012] If the outdoor ambient temperature is greater than or equal to the first temperature threshold, then the operating mode of the variable capacity compressor is determined to be two-stage mode.

[0013] In the preferred embodiment of the heating control method for the aforementioned air conditioner, the step of "selectively performing defrosting or defrosting operation based on the judgment result" further includes:

[0014] When the outdoor coil temperature is less than or equal to the dew point temperature and remains so for a first preset duration, the air conditioner is controlled to perform a defrost operation, including:

[0015] The variable capacity compressor is controlled to switch to the dual-cylinder mode, and the valve is controlled to open at a first preset opening speed until the outdoor coil temperature is greater than the dew point temperature and continues for a second preset duration, at which point the valve opening stops.

[0016] In a preferred embodiment of the heating control method for the aforementioned air conditioner, the heating control method further includes:

[0017] The variable capacity compressor is controlled by PID based on the indoor ambient temperature.

[0018] In the preferred embodiment of the heating control method for the aforementioned air conditioner, the step of "determining the operating mode of the variable capacity compressor based on the temperature range of the outdoor ambient temperature" further includes:

[0019] If the outdoor ambient temperature is less than the second temperature threshold, then the operating mode of the variable capacity compressor is determined to be the two-stage mode.

[0020] In the preferred embodiment of the heating control method for the aforementioned air conditioner, the step of "selectively performing defrosting or defrosting operation based on the judgment result" further includes:

[0021] When the outdoor coil temperature is less than or equal to the dew point temperature and remains so for a third preset duration, the air conditioner is controlled to perform a defrost operation, including:

[0022] The variable capacity compressor is controlled to switch to the dual-cylinder mode, and the valve is controlled to open at a second preset opening speed until the outdoor coil temperature is greater than the dew point temperature and continues for a fourth preset time, at which point the valve opening stops.

[0023] In the preferred embodiment of the heating control method for the aforementioned air conditioner, the step of "determining the operating mode of the variable capacity compressor based on the temperature range of the outdoor ambient temperature" further includes:

[0024] If the outdoor ambient temperature is less than the first temperature threshold and greater than or equal to the second temperature threshold, then the operating mode of the variable capacity compressor is determined to be the dual-cylinder mode.

[0025] In the preferred embodiment of the heating control method for the aforementioned air conditioner, the step of "selectively performing defrosting or defrosting operation based on the judgment result" further includes:

[0026] When the outdoor coil temperature is less than or equal to the dew point temperature and remains so for a sixth preset duration, the air conditioner is controlled to perform a defrost operation, including:

[0027] The valve is controlled to open at a third preset opening speed until the outdoor coil temperature is greater than the dew point temperature and continues for a seventh preset duration, at which point the valve opening stops.

[0028] In the preferred embodiment of the heating control method for the above-mentioned air conditioner, after stopping the valve opening, the heating control method further includes:

[0029] After a fifth preset time interval, the outdoor coil temperature and dew point temperature are acquired again, and their magnitudes are determined.

[0030] When the outdoor coil temperature is greater than the dew point temperature, the valve is closed and the variable capacity compressor is switched back to the working mode before the defrosting operation.

[0031] When the outdoor coil temperature is less than or equal to the dew point temperature, the valve is controlled to continue to open.

[0032] In the preferred embodiment of the heating control method for the aforementioned air conditioner, the step of "selectively performing defrosting or defrosting operation based on the judgment result" further includes:

[0033] When the valve is opened to its maximum opening degree and the outdoor coil temperature is still less than or equal to the dew point temperature, the air conditioner is controlled to perform a defrosting operation.

[0034] The technical solution of this application uses a variable-capacity compressor, which can operate in dual-cylinder and dual-stage modes, automatically switching modes according to the operating load and environment. This allows for different operating modes in different environments and areas, enabling a single air conditioner to be used simultaneously in both extremely cold and low-temperature, high-humidity application scenarios. Furthermore, during operation, the system performs defrosting or anti-frost operations based on the outdoor coil temperature and dew point temperature. It can also perform defrosting or anti-frost treatment on the outdoor heat exchanger according to the degree of frost buildup, improving heating performance and reducing the frequency of defrosting. Attached Figure Description

[0035] The present application will now be described with reference to the accompanying drawings. In the drawings:

[0036] Figure 1 This is a system diagram (dual-cylinder mode) of the air conditioner of this application;

[0037] Figure 2 This is a system diagram (two-stage mode) of the air conditioner of this application;

[0038] Figure 3 This is a flowchart of the heating control method for the air conditioner according to this application;

[0039] Figure 4 This is a logic diagram of one possible implementation of the heating control method for the air conditioner of this application.

[0040] List of reference numerals

[0041] 1. Compressor; 11. First compression cylinder; 12. Second compression cylinder; 13. First port; 14. Second port; 15. Third port; 16. Fourth port; 17. Exhaust port; 2. Outdoor heat exchanger; 3. Throttling device; 4. Indoor heat exchanger; 5. Air supply line; 6. Valve; 7. First four-way valve; 8. Gas-liquid separator. Detailed Implementation

[0042] Preferred embodiments of this application will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of this application and are not intended to limit the scope of protection of this application. For example, although the steps are described in a sequential order in the following embodiments, those skilled in the art will understand that, in order to achieve the effects of this embodiment, different steps need not be executed in such an order; they can be executed simultaneously (in parallel) or in a reverse order. These simple variations are all within the scope of protection of this application.

[0043] It should be noted that in the embodiments of this application, the terms "first," "second," "third," and "fourth" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, "multiple" as described in the embodiments of this application refers to two or more.

[0044] It should also be noted that, in the description of this application, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0045] First refer to Figure 1 and Figure 2 The present application describes the air conditioner.

[0046] like Figure 1 and Figure 2 As shown, the air conditioner of this application includes a variable capacity compressor 1, an indoor heat exchanger 4, a throttling device 3, and an outdoor heat exchanger 2 connected by refrigerant piping. The connection methods and working principles of the above components are common knowledge in the art and will not be described in detail here. In particular, the air conditioner also includes a gas supply pipe 5. One end of the gas supply pipe 5 is connected to the refrigerant piping between the throttling device 3 and the inlet of the outdoor heat exchanger 2, and the other end of the gas supply pipe 5 is connected to the suction port of the variable capacity compressor 1. An adjustable valve 6 is provided on the gas supply pipe 5. Preferably, the valve 6 is a solenoid valve.

[0047] The variable displacement compressor 1 has two compression cylinders. Specifically, the variable displacement compressor 1 has a first compression cylinder 11 and a second compression cylinder 12 inside. The compressor 1 housing has four ports and one exhaust port 17. The first port 13 is connected to the air inlet of the first compression cylinder 11, the second port 14 is connected to the air outlet of the first compression cylinder 11, the third port 15 is connected to the air inlet of the second compression cylinder 12, the air outlet of the second compression cylinder 12 is connected to the exhaust port 17, and the fourth port 16 is connected to the exhaust port 17 through the inside of the housing.

[0048] The variable displacement compressor 1 is also equipped with a first four-way valve 7, which has four ports a, b, c, and d. Port a is connected to the fourth port 16, port b is connected to the second port 14, and port c is connected to the third port 15. A moving part is installed inside the four-way valve. When the four-way valve is energized or de-energized, the moving part moves within the four-way valve to connect or disconnect the different ports.

[0049] The outlet of the outdoor heat exchanger 2 is connected to two gas-liquid separators 8 via a distributor. The outlets of the two gas-liquid separators 8 are respectively connected to the two compression cylinders of the variable displacement compressor 1. One gas-liquid separator 8 has its outlet directly connected to the first port 13, while the other gas-liquid separator 8 has its outlet connected indirectly to the third port 15 via the fourth port d of the first four-way valve 7. One end of the air supply line 5 is connected to the inlet of one of the gas-liquid separators 8. Figure 1 and Figure 2 The diagram shows the connection to the inlet of the gas-liquid separator 8 on the right.

[0050] Under the above configuration, the variable displacement compressor 1 operates in two-cylinder and two-stage modes. See also... Figure 1When the first four-way valve 7 is de-energized, it operates in dual-cylinder mode. In this mode, the two compression cylinders of the variable-capacity compressor 1 compress the refrigerant independently. Specifically, a portion of the refrigerant discharged from the outdoor heat exchanger 2 passes through one of the gas-liquid separators 8 and enters the first compression cylinder 11 through the first port 13. After being compressed by the first compression cylinder 11, it is discharged through the second port 14, then passes through the second port b and the first port a of the first four-way valve 7 into the housing and is finally discharged through the exhaust port 17. The other portion of the refrigerant passes through the other gas-liquid separator 8 and then through the fourth port d and the third port c of the first four-way valve 7. It then enters the second compression cylinder 12 through the third port 15, is compressed by the second compression cylinder 12, and is discharged through the exhaust port 17.

[0051] See Figure 2 When the first four-way valve 7 is energized, it operates in two-stage mode. In this mode, the two compression cylinders of the variable capacity compressor 1 compress the refrigerant sequentially. Specifically, the first port a and the fourth port d of the first four-way valve 7 are separated by a moving part. The refrigerant discharged from the outdoor heat exchanger 2 passes through one of the gas-liquid separators 8 and then enters the first compression cylinder 11 through the first port 13. After being compressed by the first compression cylinder 11, it is discharged through the second port 14. Then, after passing through the second port b and the third port c of the first four-way valve 7, it enters the second compression cylinder 12 through the third port 15. After secondary compression by the second compression cylinder 12, it is discharged through the exhaust port 17.

[0052] Those skilled in the art will understand that the above-described configuration of the air conditioner is merely a preferred embodiment. They can adjust the structure of the air conditioner without departing from the principles of this application, making it applicable to more specific application scenarios. For example, the switching between the dual-cylinder mode and the two-stage mode of the variable-capacity compressor 1 can be achieved not through the first four-way valve 7, but by setting multiple valve groups 6, controlling the opening and closing of each valve 6 within each valve group. Furthermore, the specific structural form of the variable-capacity compressor 1 is not fixed. While enabling the switching between the dual-cylinder mode and the two-stage mode, those skilled in the art can adjust the structure of the variable-capacity compressor 1, such as changing the number, position, and connection relationship of ports. Furthermore, the inclusion of a gas-liquid separator 8 is not mandatory; those skilled in the art can select it according to specific needs. Moreover, the specific form of the valve 6 is not limited; any valve body capable of electrically controlled opening and closing is applicable to this application, such as an electronic expansion valve.

[0053] The following reference Figure 3 The control method described in this application is introduced.

[0054] like Figure 3 As shown, in order to meet the heating requirements of both extremely cold and low-temperature high-humidity application scenarios, the heating control method of this application includes:

[0055] S101, Obtain the outdoor ambient temperature. For example, the outdoor ambient temperature can be obtained using a temperature sensor installed outdoors.

[0056] S103 determines the operating mode of the variable capacity compressor based on the outdoor ambient temperature range and controls the compressor to operate according to that mode. For example, the compressor's operating modes include a two-cylinder mode and a two-stage mode. In the two-cylinder mode, the refrigerant flows through both cylinders of the compressor for compression. In the two-stage mode, the refrigerant flows through both cylinders sequentially for compression. The compressor's operating mode is selected based on the outdoor ambient temperature range to ensure that the compressor is compatible with the current heating load and heating environment.

[0057] S105, During operation, the outdoor coil temperature of the outdoor heat exchanger is acquired. For example, the outdoor coil temperature is acquired using a temperature sensor installed on the outdoor heat exchanger.

[0058] S107, determine the relationship between the outdoor coil temperature and the dew point temperature corresponding to the outdoor ambient temperature. For example, the dew point temperature can be determined based on the outdoor ambient temperature, such as using a lookup table of outdoor ambient temperature and dew point temperature, or by fitting a formula. After determining the dew point temperature corresponding to the current outdoor ambient temperature, the relationship between the outdoor coil temperature and the dew point temperature is determined by calculating the difference, ratio, etc.

[0059] S109, based on the judgment result, selectively perform defrosting or defrosting operations. For example, when the outdoor coil temperature is less than or equal to the dew point temperature, the outdoor unit is prone to frost formation. In this case, defrosting operation is performed first, and defrosting operation is performed if defrosting operation is ineffective. Alternatively, the degree of frost formation is determined based on the judgment result; defrosting operation is performed if the degree of frost formation is slight, and defrosting operation is performed if the degree of frost formation is severe, etc.

[0060] The technical solution of this application uses a variable-capacity compressor, which can operate in dual-cylinder and dual-stage modes, automatically switching modes according to the operating load and environment. This allows for different operating modes in different environments and areas, enabling a single air conditioner to be used simultaneously in both extremely cold and low-temperature, high-humidity application scenarios. Furthermore, during operation, the system performs defrosting or anti-frost operations based on the outdoor coil temperature and dew point temperature. It can also perform defrosting or anti-frost treatment on the outdoor heat exchanger according to the degree of frost buildup, improving heating performance and reducing the frequency of defrosting.

[0061] The preferred embodiments of the heating control method of this application are described below.

[0062] In one embodiment, the step of "determining the operating mode of the variable capacity compressor based on the temperature range of the outdoor ambient temperature" further includes: if the outdoor ambient temperature is greater than or equal to a first temperature threshold, then the operating mode of the variable capacity compressor is determined to be a two-stage mode; if the outdoor ambient temperature is less than the first temperature threshold but greater than or equal to a second temperature threshold, then the operating mode of the variable capacity compressor is determined to be a two-cylinder mode; if the outdoor ambient temperature is less than the second temperature threshold, then the operating mode of the variable capacity compressor is determined to be a two-stage mode.

[0063] Specifically, the first temperature threshold is any value between 4 and 10°C, and the second temperature threshold is any value between -10 and 0°C. In the following embodiments of this application, an example is given with a first temperature threshold of 7°C and a second temperature threshold of -5°C. When the outdoor ambient temperature is greater than or equal to 7°C, the indoor load is small. Controlling the compressor to operate in two-stage mode can reduce the compressor's operating frequency and noise, reduce heat loss, and achieve efficient and energy-saving operation. When the outdoor ambient temperature is less than 7°C but greater than or equal to -5°C, the outdoor temperature decreases, the indoor load increases, and a greater heating capacity is required. Controlling the compressor to operate in dual-cylinder mode allows for a larger discharge volume at the same frequency, thereby improving heating and cooling effects. When the outdoor ambient temperature is less than -5°C, the low outdoor temperature and large indoor load require a sufficiently high condensing temperature for heat exchange. Ordinary compressors in low-temperature environments increase the compression ratio to achieve this, but increasing the compression ratio does not significantly increase the discharge temperature and may lead to refrigerant leakage, thus reducing the heating effect. This application switches the compressor's operating mode to a two-stage mode, which can achieve a larger compression ratio at a lower operating frequency, thereby meeting the condensing temperature requirements.

[0064] Of course, the above-mentioned temperature range division and compressor operating mode selection are only preferred options. In other embodiments, those skilled in the art can adjust the temperature range division method, such as dividing more temperature ranges or reducing them to fewer temperature ranges, and then adjust the compressor operating mode specifically for each temperature range to achieve efficient and stable operation of the compressor.

[0065] In one embodiment, the control method further includes: when the outdoor ambient temperature is greater than or equal to a first temperature threshold, performing PID control on the variable capacity compressor based on the indoor ambient temperature. Specifically, when the outdoor ambient temperature is greater than or equal to 7°C, the indoor load is small, the compressor operates stably, and only PID control of the compressor based on the indoor ambient temperature is needed to fully meet the heating and warming needs.

[0066] Those skilled in the art will understand that using PID control to control the compressor frequency is merely a preferred technical solution, and they may choose other control methods.

[0067] In one embodiment, the dew point temperature is determined based on the outdoor ambient temperature. Preferably, the dew point temperature is determined based on the following formula:

[0068] Tes=C×Tao-α(1)

[0069] In formula (1), Tes is the dew point temperature, Tao is the outdoor ambient temperature, C is the temperature coefficient, and α is the correction constant. Of course, those skilled in the art can also use other methods to calculate the dew point temperature, such as a table comparing outdoor ambient temperature and dew point temperature.

[0070] In one embodiment, when the outdoor ambient temperature is greater than or equal to a first temperature threshold, the step of "selectively performing defrosting or defrosting operation based on the judgment result" further includes: when the outdoor coil temperature is less than or equal to the dew point temperature and lasts for a first preset duration, controlling the air conditioner to perform defrosting operation includes: controlling the variable capacity compressor to switch to dual-cylinder mode, and controlling the valve to perform valve opening operation according to a first preset valve opening speed, until the outdoor coil temperature is greater than the dew point temperature and lasts for a second preset duration, at which point the valve opening stops.

[0071] Specifically, the first preset duration is any value between 1 and 10 minutes; this application uses 5 minutes as an example. When the outdoor coil temperature is less than or equal to the dew point temperature and remains so for 5 minutes, the outdoor heat exchanger has already begun to frost or is about to form a frost layer under the current outdoor ambient temperature. At this time, it is necessary to promptly suppress the continued formation of the frost layer; therefore, the defrosting operation is initiated. The first preset valve opening speed is preferably 10 B / s, and the second preset duration is any value between 1 and 5 minutes, preferably 2 minutes. First, the variable-capacity compressor is switched to dual-cylinder mode, and then the valve is controlled to open at a valve opening speed of 10 B / s. Under the same discharge capacity, when the compressor operates in dual-cylinder mode, the discharge capacity is the sum of the discharge capacities of the upper and lower compression cylinders. The operating frequency is low, the compressor compression ratio is reduced, the high pressure of the air conditioning system becomes lower, and the low pressure becomes higher, delaying frost formation. Controlling the valve to open allows some refrigerant to return to the gas-liquid separator without being heat-exchanged in the outdoor heat exchanger, thereby further increasing the return gas pressure and delaying frost formation. The combined effect of these two factors can quickly achieve rapid defrosting of the outdoor heat exchanger. During the defrosting operation, the outdoor coil temperature is acquired in real time. When the outdoor coil temperature is higher than the dew point temperature and remains higher for 2 minutes, there is no risk of frost forming on the outdoor heat exchanger. At this time, the control valve stops opening.

[0072] Of course, the first preset duration, the second preset duration, and the first preset valve opening speed are merely illustrative examples and are not intended to limit the scope of protection of this application. Those skilled in the art can adjust the above values ​​based on specific application scenarios. Furthermore, the specific form of the defrosting operation is not unique. Those skilled in the art can perform only one of the above compressor switching mode and valve opening operation, but this will obviously affect the defrosting effect.

[0073] In one embodiment, when the outdoor ambient temperature is less than a second temperature threshold, the step of "selectively performing defrosting or defrosting operation based on the judgment result" further includes: when the outdoor coil temperature is less than or equal to the dew point temperature and lasts for a third preset duration, controlling the air conditioner to perform defrosting operation includes: controlling the variable capacity compressor to switch to dual-cylinder mode, and controlling the valve to perform valve opening operation according to a second preset valve opening speed, until the outdoor coil temperature is greater than the dew point temperature and lasts for a fourth preset duration, at which point the valve opening stops.

[0074] Specifically, the third preset duration is any value between 1 and 5 minutes; this application uses 2 minutes as an example. When the outdoor coil temperature is less than or equal to the dew point temperature and remains so for 2 minutes, the outdoor heat exchanger has already begun to frost or is about to form a frost layer under the current outdoor ambient temperature. At this time, it is necessary to promptly suppress the continued formation of the frost layer; therefore, the defrosting operation is initiated. The second preset valve opening speed is preferably 10 B / s, and the fourth preset duration is any value between 1 and 5 minutes, preferably 2 minutes. First, the variable-capacity compressor is switched to dual-cylinder mode, and then the valve is controlled to open at a valve opening speed of 10 B / s. Under the same discharge capacity, when the compressor operates in dual-cylinder mode, the discharge capacity is the sum of the discharge capacities of the upper and lower compression cylinders. The operating frequency is low, the compressor compression ratio is reduced, the high pressure of the air conditioning system becomes lower, and the low pressure becomes higher, delaying frost formation. Controlling the valve to open allows some refrigerant to return to the gas-liquid separator without being heat-exchanged by the outdoor heat exchanger, thereby further increasing the return gas pressure and delaying frost formation. The combined effect of these two factors can quickly achieve rapid defrosting of the outdoor heat exchanger. During the defrosting operation, the outdoor coil temperature is acquired in real time. When the outdoor coil temperature is higher than the dew point temperature and remains higher for 2 minutes, there is no risk of frost forming on the outdoor heat exchanger. At this time, the control valve stops opening.

[0075] Of course, the third preset duration, the fourth preset duration, and the second preset valve opening speed are merely illustrative examples and are not intended to limit the scope of protection of this application. Those skilled in the art can adjust the above values ​​based on specific application scenarios. Furthermore, the specific form of the defrosting operation is not unique. Those skilled in the art can perform only one of the above compressor switching mode and valve opening operation, but this will obviously affect the defrosting effect.

[0076] In one embodiment, when the outdoor ambient temperature is less than a first temperature threshold and greater than or equal to a second temperature threshold, the step of "selectively performing defrosting or defrosting operation based on the judgment result" further includes: when the outdoor coil temperature is less than or equal to the dew point temperature and lasts for a sixth preset duration, controlling the air conditioner to perform defrosting operation includes: controlling the valve to perform valve opening operation at a third preset valve opening speed until the outdoor coil temperature is greater than the dew point temperature and lasts for a seventh preset duration, then stopping the valve opening.

[0077] Specifically, the sixth preset duration is any value between 1 and 6 minutes; this application uses 3 minutes as an example. When the outdoor coil temperature is less than or equal to the dew point temperature and remains so for 3 minutes, the outdoor heat exchanger has already begun to frost or is about to form a frost layer under the current outdoor ambient temperature. At this time, it is necessary to promptly suppress the continued formation of the frost layer; therefore, the defrosting operation is initiated. The third preset valve opening speed is preferably 10 B / s, and the seventh preset duration is any value between 1 and 5 minutes, preferably 2 minutes. Since the compressor is already in dual-cylinder mode, there is no need to switch modes. Then, the control valve opens at a valve opening speed of 10 B / s. Under the same discharge capacity, when the compressor operates in dual-cylinder mode, the discharge capacity is the sum of the discharge capacities of the upper and lower compression cylinders. The operating frequency is low, the compressor's compression ratio decreases, the high pressure of the air conditioning system decreases, the low pressure increases, and frost formation is delayed. The control valve opening allows some refrigerant to return to the gas-liquid separator without being heated by the outdoor heat exchanger, thereby further increasing the return gas pressure and delaying frost formation. The combined effect of these two factors can quickly achieve rapid defrosting of the outdoor heat exchanger. During the defrosting operation, the outdoor coil temperature is acquired in real time. When the outdoor coil temperature is higher than the dew point temperature and remains higher for 2 minutes, there is no risk of frost forming on the outdoor heat exchanger. At this time, the control valve stops opening.

[0078] Of course, the sixth preset duration, the seventh preset duration, and the third preset valve opening speed are merely illustrative examples and are not intended to limit the scope of protection of this application. Those skilled in the art can adjust the above values ​​based on specific application scenarios.

[0079] In one embodiment, after stopping the valve opening, the heating control method further includes: after a fifth preset time interval, acquiring the outdoor coil temperature and dew point temperature again, and determining their magnitudes; when the outdoor coil temperature is greater than the dew point temperature, controlling the valve to close and controlling the variable capacity compressor to switch back to the working mode before the defrosting operation; when the outdoor coil temperature is less than or equal to the dew point temperature, controlling the valve to continue opening.

[0080] Specifically, the fifth preset duration is any value between 10 and 20 minutes; this application uses 15 minutes as an example. After 15 minutes of valve opening being stopped, the outdoor coil temperature and dew point temperature are acquired again, and their values ​​are compared. If the outdoor coil temperature is greater than the dew point temperature, it proves that the outdoor heat exchanger has no risk of frosting. At this time, the control valve is closed, and the variable capacity compressor is controlled to return to the heating mode before switching. That is, if the variable capacity compressor is operating in two-stage mode in heating mode, it switches back to two-stage mode; if it is operating in dual-cylinder mode in heating mode, no switching is required, and the current mode continues to be maintained. Conversely, if the outdoor coil temperature is less than or equal to the dew point temperature, the control valve continues to open, and defrosting operation is performed on the outdoor heat exchanger.

[0081] Those skilled in the art will understand that the specific value of the fifth preset duration is not unique and can be adjusted. Furthermore, the above steps are not mandatory, and those skilled in the art can choose whether to adopt the above steps based on the specific application scenario.

[0082] In one embodiment, the step of "selectively performing defrosting or defrosting operation based on the judgment result" further includes: controlling the air conditioner to perform defrosting operation when the valve is opened to the maximum degree and the outdoor coil temperature is still less than or equal to the dew point temperature.

[0083] Specifically, the valve has an opening range. During the defrosting operation, when the valve opening reaches its maximum and cannot be opened further, if the outdoor coil temperature is still lower than the dew point temperature, it proves that the valve opening operation can no longer suppress frost formation on the outdoor heat exchanger. At this time, the air conditioner is controlled to perform a defrosting operation. The specific form of the defrosting operation is not limited in this application; it can be reverse circulation defrosting, or shutdown defrosting, etc.

[0084] The following is combined Figure 4 This paper briefly describes one possible operating process of the air conditioner according to this application. Figure 4 As shown, in one possible operation:

[0085] S201, obtain the outdoor ambient temperature Tout, and then execute S202.

[0086] S202, determine if Tout≤29℃ is true? If true, execute S204; otherwise, if false, execute S203.

[0087] S203, further determine whether Tout < -5℃ is true? If true, then execute S206; otherwise, if false, then execute S205.

[0088] S204 controls the compressor to operate in a two-stage mode and performs PID control on the compressor frequency based on the indoor ambient temperature.

[0089] S205 controls the compressor to operate in dual-cylinder mode.

[0090] S206 controls the compressor to operate in two-stage mode.

[0091] S207, obtain the outdoor coil temperature Tp, and then execute S208.

[0092] S208. Determine if TP≤Tes and this condition is met for 2 minutes. If it is met, proceed to S209; otherwise, if it is not met, return to S207. Here, Tes is the dew point temperature corresponding to the outdoor ambient temperature.

[0093] S209, Perform defrosting operation. This includes switching the compressor to dual-cylinder mode (no switching is needed if it's already in dual-cylinder mode), and controlling the valve to open at a rate of 10 B / s. During valve opening, the outdoor coil temperature is continuously acquired and compared with the dew point temperature. If the outdoor coil temperature is less than or equal to the dew point temperature, valve opening continues; otherwise, it stops. After stopping valve opening for 15 minutes, the outdoor coil temperature is acquired again and compared with the dew point temperature. If the outdoor coil temperature is less than or equal to the dew point temperature, valve opening continues; otherwise, it closes the valve and controls the compressor to switch back to the heating mode.

[0094] S210, During the defrosting operation, determine whether the valve is opened to its maximum opening. If yes, execute S211; otherwise, return to continue executing the defrosting operation.

[0095] S211, Perform defrosting operation on the outdoor heat exchanger.

[0096] It should be noted that although the detailed steps of the method of this application have been described in detail above, those skilled in the art can combine, split and rearrange the above steps without departing from the basic principles of this application. Such modified technical solutions do not change the basic concept of this application and therefore fall within the protection scope of this application.

[0097] Those skilled in the art will understand that although some embodiments described herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of this application and form different embodiments. For example, any of the claimed embodiments in the claims of this application can be used in any combination.

[0098] It should be noted that although the detailed steps of the method of this application have been described in detail above, those skilled in the art can combine, split and rearrange the above steps without departing from the basic principles of this application. Such modified technical solutions do not change the basic concept of this application and therefore fall within the protection scope of this application.

[0099] The technical solutions of this application have been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of this application is obviously not limited to these specific embodiments. Without departing from the principles of this application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of this application.

Claims

1. A heating control method of an air conditioner, characterized by, The air conditioner includes a variable-capacity compressor, an indoor heat exchanger, a throttling device, and an outdoor heat exchanger connected sequentially via refrigerant piping. The variable-capacity compressor has two compression cylinders. The air conditioner also includes a gas supply line, one end of which is connected to the refrigerant piping between the throttling device and the inlet of the outdoor heat exchanger, and the other end of which is connected to the suction port of the variable-capacity compressor. The gas supply line is equipped with an adjustable valve. The heating control method includes: Obtain the outdoor ambient temperature; Based on the temperature range of the outdoor ambient temperature, the operating mode of the variable capacity compressor is determined, and the variable capacity compressor is controlled to operate according to the operating mode. During operation, the outdoor coil temperature of the outdoor heat exchanger is obtained; Determine the magnitude of the difference between the outdoor coil temperature and the dew point temperature corresponding to the outdoor ambient temperature; Based on the judgment result, selectively perform defrosting or defrosting operations; The variable capacity compressor has two operating modes: a dual-cylinder mode and a two-stage mode. In the dual-cylinder mode, the two compression cylinders of the variable capacity compressor compress the refrigerant individually. In the two-stage mode, the two compression cylinders of the variable capacity compressor compress the refrigerant sequentially. The step of "determining the operating mode of the variable capacity compressor based on the outdoor ambient temperature range" further includes: If the outdoor ambient temperature is greater than or equal to the first temperature threshold, then the operating mode of the variable capacity compressor is determined to be two-stage mode; The step of "selectively performing defrosting or refrost-reducing operations based on the judgment result" further includes: When the outdoor coil temperature is less than or equal to the dew point temperature and remains so for a first preset duration, the air conditioner is controlled to perform a defrost operation, including: The variable capacity compressor is controlled to switch to the dual-cylinder mode, and the valve is controlled to open at a first preset opening speed until the outdoor coil temperature is greater than the dew point temperature and continues for a second preset duration, at which point the valve opening stops. The step of "determining the operating mode of the variable capacity compressor based on the outdoor ambient temperature range" further includes: If the outdoor ambient temperature is less than the second temperature threshold, then the operating mode of the variable capacity compressor is determined to be the two-stage mode; If the outdoor ambient temperature is less than the first temperature threshold and greater than or equal to the second temperature threshold, then the operating mode of the variable capacity compressor is determined to be the dual-cylinder mode.

2. The heating control method of the air conditioner according to claim 1, wherein The heating control method further includes: The variable capacity compressor is controlled by PID based on the indoor ambient temperature.

3. The heating control method for an air conditioner according to claim 1, characterized in that, The step of "selectively performing defrosting or refrost-reducing operations based on the judgment result" further includes: When the outdoor coil temperature is less than or equal to the dew point temperature and remains so for a third preset duration, the air conditioner is controlled to perform a defrost operation, including: The variable capacity compressor is controlled to switch to the dual-cylinder mode, and the valve is controlled to open at a second preset opening speed until the outdoor coil temperature is greater than the dew point temperature and continues for a fourth preset time, at which point the valve opening stops.

4. The heating control method for an air conditioner according to claim 1, characterized in that, The step of "selectively performing defrosting or refrost-reducing operations based on the judgment result" further includes: When the outdoor coil temperature is less than or equal to the dew point temperature and remains so for a sixth preset duration, the air conditioner is controlled to perform a defrost operation, including: The valve is controlled to open at a third preset opening speed until the outdoor coil temperature is greater than the dew point temperature and continues for a seventh preset duration, at which point the valve opening stops.

5. The heating control method for an air conditioner according to claim 1, 3, or 4, characterized in that, After the valve opening is stopped, the heating control method further includes: After a fifth preset time interval, the outdoor coil temperature and dew point temperature are acquired again, and their magnitudes are determined. When the outdoor coil temperature is greater than the dew point temperature, the valve is closed and the variable capacity compressor is switched back to the working mode before the defrosting operation. When the outdoor coil temperature is less than or equal to the dew point temperature, the valve is controlled to continue to open.

6. The heating control method for an air conditioner according to claim 1, 3, or 4, characterized in that, The step of "selectively performing defrosting or refrost-reducing operations based on the judgment result" further includes: When the valve is opened to its maximum opening degree and the outdoor coil temperature is still less than or equal to the dew point temperature, the air conditioner is controlled to perform a defrosting operation.

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