A gas supplementing and enthalpy increasing heat pump air conditioner and a refrigeration operation control method thereof

Abstract

The present application relates to the technical field of heat pump, especially to a kind of air injection enthalpy-increasing heat pump air conditioner and its refrigeration operation control method, in normal refrigeration operation process, reach the throttling state required when unit operation by two throttling of first throttling mechanism and second throttling mechanism, wherein second throttling mechanism exists non-air injection state basic operation opening degree when unit does not carry out air injection operation, second throttling mechanism exists air injection operation minimum operation opening degree when unit carries out air injection operation, wherein air injection operation minimum operation opening degree is less than non-air injection state basic operation opening degree (the throttling degree of second throttling mechanism in air injection state is greater);Air injection can be realized by the relative opening degree size of first throttling mechanism and second throttling mechanism when air injection, air injection operation or liquid injection operation.When compressor discharge temperature is too high and there is the possibility of reducing compressor operation reliability, air injection (or liquid injection) amount can be controlled, and the problem of being unable to effectively control air injection or liquid injection amount is solved.

Description

Technical Field

[0001] This invention relates to the field of heat pump technology, and in particular to a gas-injection enthalpy-increasing heat pump air conditioner and its refrigeration operation control method. Background Technology

[0002] Air conditioners are widely used in people's work and daily life, and some existing air conditioners use compressors with gas replenishment function. The main principle of a compressor with gas replenishment function is to set up a gas replenishment port (medium-pressure chamber) between the compressor's suction chamber and discharge chamber. By replenishing gaseous refrigerant or a small amount of liquid refrigerant into the gas replenishment port (medium-pressure chamber), the compressor's discharge temperature can be reduced in cooling mode.

[0003] In cooling operation mode, when the outdoor ambient temperature is high, the compressor discharge temperature is often set very high to allow the outdoor heat exchanger to release heat to the outside. When the compressor discharge temperature is too high (in some cases, it may exceed the compressor's normal operating range), the compressor's operational reliability will decrease. In this situation, by adding a small amount of liquid refrigerant to the compressor's inlet (intermediate pressure chamber), the liquid refrigerant evaporates inside the compressor, quickly absorbing heat from within and thus lowering the compressor discharge temperature. This method can quickly reduce the compressor's discharge temperature and improve the compressor's operational reliability.

[0004] In cooling mode, when liquid refrigerant is added to the gas inlet (intermediate pressure chamber) to reduce the compressor's discharge temperature, an unreasonable amount of refrigerant added can cause the following problems:

[0005] ① Excessive addition of liquid refrigerant: The liquid refrigerant entering the gas inlet (medium pressure chamber) cannot be completely evaporated into gaseous refrigerant, resulting in liquid compression inside the compressor, which affects the operating stability and service life of the compressor;

[0006] ② Insufficient liquid refrigerant: If too little liquid refrigerant enters the gas inlet (medium pressure chamber), the compressor cannot be reduced to the expected temperature, resulting in excessively high compressor discharge temperature and affecting the compressor's service life. Summary of the Invention

[0007] To address the aforementioned problems, the present invention aims to provide a gas-injection enthalpy-increasing heat pump air conditioner and its refrigeration operation control method. When the compressor exhaust temperature is too high and there is a possibility of reduced compressor operation reliability, the gas (or liquid) injection amount can be controlled, thus solving the problem that the gas or liquid injection amount cannot be effectively controlled when the heat pump air conditioner uses intermediate gas or liquid injection methods to reduce the compressor exhaust temperature.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] A method for controlling the cooling operation of a gas-injected enthalpy-increasing heat pump air conditioner, characterized in that it includes an application to the gas-injected enthalpy-increasing heat pump air conditioner, which includes a controller, an indoor unit, and an outdoor unit;

[0010] The indoor unit includes an indoor heat exchanger, an indoor ambient temperature sensor, an indoor heat exchanger temperature sensor, and an indoor fan;

[0011] The outdoor unit includes a compressor, a four-way reversing valve, an outdoor heat exchanger, an outdoor fan, a first throttling mechanism, a second throttling mechanism, a flash tank, a two-way valve, an exhaust temperature sensor, an outdoor ambient temperature sensor, and an outdoor heat exchanger temperature sensor.

[0012] The indoor unit and the outdoor unit form a loop through the first refrigerant connection pipe and the second refrigerant connection pipe;

[0013] The flash tank has a first port, a second port, and a third port. The first port is located near the bottom of the flash tank, the second port is located near the bottom of the flash tank, and the third port is located near the top of the flash tank. The compressor has a gas inlet. The first port is connected to the outdoor heat exchanger, and the pipe between the outdoor heat exchanger and the first port is equipped with the first throttling mechanism. The second port is connected to the indoor heat exchanger through the first refrigerant connection pipe, and the first refrigerant connection pipe is equipped with the second throttling mechanism. The third port is connected to the gas inlet, and the pipe between the third port and the gas inlet is equipped with the two-way valve.

[0014] When the heat pump air conditioner is in cooling mode, the first pipe is the refrigerant inlet, the second pipe is the refrigerant outlet, and the third pipe is the gas or liquid replenishment outlet; when the heat pump air conditioner is in heating mode, the second pipe is the refrigerant inlet, the first pipe is the refrigerant outlet, and the third pipe is the gas or liquid replenishment outlet.

[0015] The refrigeration operation control method includes the following steps:

[0016] S1: Set D as the first operation mark. The factory default is D=0. D=0 marks the first operation, and D=1 marks a non-first operation. Set the outdoor fan high-speed wind reference power to PRhs.

[0017] When the air conditioner is turned on, the controller receives the operating parameter information set by the user. Let t be a time statistics parameter, and let t=0.

[0018] The controller determines whether the current operating mode is cooling mode. If it is cooling mode, it checks the value of the initial operation marker D.

[0019] If D=0, set the outdoor fan speed to high speed, count the time t, compare the counted time t with the first time judgment threshold a. If t≥a, obtain the current outdoor fan high speed power PRh, set D=1, PRhs=PRh, t=0, and obtain the outdoor ambient temperature To.

[0020] If D=1, directly obtain the outdoor ambient temperature To;

[0021] S2: Set Tdtar to the target compressor exhaust temperature; set P2s to the reference opening degree of the second throttling mechanism in non-replenishment state;

[0022] The controller acquires P2s and Tdtar, causing the first throttling mechanism to operate automatically. The opening degree of the second throttling mechanism P2 is set to P2s. The air conditioner operates automatically according to the set parameters and acquires the compressor discharge temperature Td.

[0023] S3: Compare Td with the exhaust temperature judgment threshold b. If Td≥b, set the outdoor fan speed to the high-speed fan speed Rh, obtain the outdoor fan high-speed power PRh, calculate the actual power judgment coefficient △P=PRh / PRhs, obtain the exhaust temperature correction coefficient △T based on the value of △P, and record the current compressor power Pcom.

[0024] S4: Compare Td with the difference between the preset exhaust temperature judgment threshold b and ΔT, b-ΔT:

[0025] If Td≥b-△T, obtain the compressor frequency F and the second correction coefficient β of the second throttling mechanism opening, and make the first throttling mechanism run automatically. The opening P2 of the second throttling mechanism is adjusted to the product β×P2 of the current opening P2 and the second correction coefficient β of the second throttling mechanism opening.

[0026] If Td < b - △T, obtain the compressor frequency F and the first correction coefficient α of the second throttling mechanism opening, and make the first throttling mechanism run automatically. The opening P2 of the second throttling mechanism is adjusted to the product α × P2 of the current opening P2 and the first correction coefficient α of the second throttling mechanism opening.

[0027] S5: Obtain and record the current compressor discharge temperature Td, open the two-way valve, count the time t, compare the counted time t with the preset time judgment threshold d, if t≥d, set t=0, obtain the current compressor power Pcom' and the current discharge temperature Td', calculate the compressor power judgment coefficient △Pcom=Pcom' / Pcom, and calculate the discharge temperature change value △Td=Td-Td';

[0028] S6: Compare the calculated compressor power judgment coefficient ΔPcom with the preset compressor power judgment threshold e:

[0029] If △Pcom≥e, let both the first and second throttling mechanisms maintain their current operating state, and continue to compare the compressor discharge temperature Td with the discharge temperature judgment threshold g. If Td≤g, close the two-way valve and return to S1 to obtain the outdoor ambient temperature To.

[0030] If △Pcom < e, compare △Td with the preset exhaust temperature change judgment threshold f:

[0031] ① If △Td≥f, let both the first and second throttling mechanisms maintain their current operating state, and continue to compare the compressor discharge temperature Td with the discharge temperature judgment threshold g. If Td≤g, close the two-way valve and return to S1 to obtain the outdoor ambient temperature To.

[0032] ② If △Td<f, then compare the compressor exhaust temperature Td with the exhaust temperature judgment threshold g. If Td≤g, close the two-way valve and return to S1 to obtain the outdoor ambient temperature To; if Td>g, return to S3 to set the outdoor fan speed to the high-speed fan speed Rh and obtain the outdoor fan high-speed power PRh.

[0033] As a preferred option, in S3, if Td < b, return to S1 to obtain the outdoor ambient temperature To.

[0034] As a preferred option, in S5, if t < d, then continue to count time t until t ≥ d.

[0035] Preferably, in S6, if △Pcom≥e and Td>g, both the first throttling mechanism and the second throttling mechanism are kept in their current operating state until Td≤g.

[0036] Preferably, the controller includes an indoor control mechanism and an outdoor control mechanism that can communicate with each other and control the indoor unit and the outdoor unit respectively.

[0037] Preferably, the indoor control mechanism includes a user information receiving module, a first operation information acquisition module, a first operation status judgment module, a first operation status control module, a first operation status information storage module, a first time statistics module, and a first information sending / receiving module; wherein:

[0038] The user information receiving module is suitable for receiving the air conditioner operation status setting parameters set by the user;

[0039] The first operation information acquisition module is suitable for acquiring the operation status information of each component in the indoor unit;

[0040] The first operating status judgment module is suitable for judging the operating status of the indoor unit.

[0041] The first operating status control module is suitable for controlling the operating status of various components in the indoor unit;

[0042] The first operating status information storage module is suitable for storing the operating status information of the indoor unit;

[0043] The first-time statistics module is suitable for calculating the operating time of the indoor unit in various operating modes and states.

[0044] The first information sending / receiving module is suitable for communicating with the outdoor control mechanism.

[0045] Preferably, the outdoor control mechanism includes a second operating status acquisition module, a second operating status judgment module, a second operating status control module, a second operating status information storage module, a second time statistics module, and a second information sending / receiving module; wherein...

[0046] The second operating status acquisition module is suitable for acquiring the operating status information of various components in the outdoor unit;

[0047] The second operating status judgment module is suitable for judging the operating status of the outdoor unit.

[0048] The second operating status control module is suitable for controlling the operating status of various components in the outdoor unit;

[0049] The second operating status information storage module is suitable for storing the operating status information of the outdoor unit;

[0050] The second time statistics module is suitable for calculating the operating time of the outdoor unit in various operating modes and operating states.

[0051] The second information sending / receiving module is suitable for communicating with the indoor control mechanism.

[0052] A gas-injection enthalpy-increasing heat pump air conditioner, characterized in that: it applies the cooling operation control method of a gas-injection enthalpy-increasing heat pump air conditioner described in any one of the above.

[0053] The present invention, by adopting the above technical solution, has the following beneficial effects:

[0054] ① The present invention divides the outdoor ambient temperature into multiple control zones and implements different control methods in each control zone.

[0055] ② During normal refrigeration operation, the unit achieves the required throttling state through two throttling mechanisms: the first and second throttling mechanisms. The second throttling mechanism has a basic operating opening when the unit is not in gas replenishment mode, and a minimum operating opening when the unit is in gas replenishment mode. The minimum operating opening for gas replenishment mode is smaller than the basic operating opening for non-gas replenishment mode (the throttling degree of the second throttling mechanism is greater in gas replenishment mode). During gas replenishment, gas replenishment or liquid replenishment mode can be achieved by adjusting the relative opening of the first and second throttling mechanisms.

[0056] ③ During refrigeration operation, when it is necessary to replenish gas or liquid to reduce the compressor discharge temperature, the lower the compressor frequency (the lower the compressor frequency, the worse the compressor operation is at this time), the more steps the second throttling mechanism closes, and the first throttling mechanism will open simultaneously. After passing through the first throttling mechanism, the refrigerant dryness (the proportion of gaseous refrigerant after passing through the first throttling mechanism) decreases, and the more liquid refrigerant is contained in the replenished gas. The discharge temperature is quickly reduced by replenishing the gas-liquid two-phase refrigerant.

[0057] ④ When the compressor frequency is high and the compressor operating conditions are not severe (when the exhaust temperature is not reduced by lowering the compressor frequency), the exhaust temperature can be slightly reduced by adding gaseous refrigerant.

[0058] ⑤ During normal refrigeration operation, when the unit is not in operation with gas replenishment, the basic opening of the second throttling mechanism in the non-gas replenishment state is related to the compressor operating frequency. The lower the compressor operating frequency, the smaller the basic opening of the second throttling mechanism in the non-gas replenishment state.

[0059] ⑥ The degree of gas replenishment can be judged by the rate of decrease in exhaust temperature or the proportion of increase in compressor power after entering the gas replenishment operation. When the rate of decrease in exhaust temperature or the proportion of increase in compressor power reaches a certain level, the throttling mechanism maintains the current opening; otherwise, the throttling mechanism continues to adjust.

[0060] ⑦ During the gas replenishment operation, when the exhaust temperature reaches the first gas replenishment temperature, the exhaust temperature is reduced by replenishing gaseous refrigerant; when the exhaust temperature reaches the second gas replenishment temperature, the exhaust temperature is reduced by replenishing liquid refrigerant.

[0061] ⑧ The control of gas or liquid replenishment is reflected in the values ​​of α and β. The smaller the values ​​of α and β, the more liquid refrigerant and the less gaseous refrigerant is replenished, and vice versa.

[0062] ⑨ By comparing the actual operating power of the outdoor fan with the fan power during the initial operation, the exhaust temperature for which the air supply control is initiated is corrected based on the comparison results. During the initial operation of the unit, the power of the outdoor fan at high speed can be recorded. This recorded power is the standard operating power of the fan and can be used to correct the exhaust temperature control during subsequent air supply control. This avoids the occurrence of untimely air supply control and exhaust protection shutdown due to dirt or blockage of the outdoor heat exchanger.

[0063] ⑩ When the exhaust temperature drops below a certain value, stop the gas (liquid) replenishment control. Attached Figure Description

[0064] Figure 1 This is a schematic diagram of the structure of the gas-injection enthalpy-increasing heat pump air conditioner involved in this invention.

[0065] Figure 2 This is a schematic diagram of the control mechanism involved in the present invention.

[0066] Figure 3 This is a schematic diagram showing the target exhaust temperature of the air conditioner involved in this invention under various operating conditions.

[0067] Figure 4 This is a schematic diagram illustrating the basic opening degree of the second throttling mechanism involved in the present invention in the non-air replenishment state.

[0068] Figure 5 This is a schematic diagram showing the value of the control coefficient α of the second throttling mechanism involved in this invention during air replenishment operation.

[0069] Figure 6 This is a schematic diagram showing the values ​​of the exhaust temperature correction coefficient involved in this invention.

[0070] Figure 7 This is a schematic diagram of the control logic during the cooling operation of the gas-injection enthalpy-increasing type heat pump air conditioner involved in this invention. Detailed Implementation

[0071] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0072] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0073] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more, unless explicitly defined otherwise.

[0074] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., 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 invention according to the specific circumstances.

[0075] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature. Example 1:

[0076] like Figures 1-2 The illustrated gas-injection enthalpy-increasing heat pump air conditioner includes a gas-injection enthalpy-increasing heat pump air conditioner 1, which includes a controller, an indoor unit 10, and an outdoor unit 20; the indoor unit 10 includes an indoor heat exchanger 101, an indoor ambient temperature sensor 102, an indoor heat exchanger temperature sensor 103, and an indoor fan 104.

[0077] The outdoor unit 20 includes a compressor 201, a four-way reversing valve 202, an outdoor heat exchanger 203, an outdoor fan 204, a first throttling mechanism 205, a second throttling mechanism 206, a flash tank 207, a two-way valve 208, an exhaust temperature sensor 209, an outdoor ambient temperature sensor 210, and an outdoor heat exchanger temperature sensor 211.

[0078] The indoor unit 10 and the outdoor unit 20 form a circuit through the first refrigerant connection pipe 30 and the second refrigerant connection pipe 40;

[0079] The flash tank 207 has a first port 7a, a second port 7b, and a third port 7c. The first port 7a is located near the bottom of the flash tank 207, the second port 7b is located near the bottom of the flash tank 207, and the third port 7c is located near the top of the flash tank 207. The compressor 201 has a gas supply port 1a. The first port 7a is connected to the outdoor heat exchanger 203, and the pipe between the outdoor heat exchanger 203 and the first port 7a is provided with the first throttling mechanism 205. The second port 7b is connected to the indoor heat exchanger 101 through the first refrigerant connection pipe 30, and the first refrigerant connection pipe 30 is provided with the second throttling mechanism 206. The third port 7c is connected to the gas supply port 1a, and the pipe between the third port 7c and the gas supply port 1a is provided with the two-way valve 208.

[0080] The first throttling mechanism 205 and the second throttling mechanism 206 involved in this invention can be flow-adjustable electronic expansion valves (or other flow-adjustable throttling mechanisms). During refrigeration operation, the throttling mechanism automatically adjusts according to the actual operating state of the unit, and its adjustment method can be controlled according to the target exhaust temperature, target exhaust superheat, etc. In this invention, the throttling mechanism is described in terms of an electronic expansion valve, and the electronic expansion valve is described in terms of target exhaust temperature control.

[0081] The two-way valve 208 involved in this invention has two states: open and closed. When the two-way valve 208 is open, refrigerant can flow inside it; when the two-way valve 208 is closed, refrigerant cannot flow inside it.

[0082] When the heat pump air conditioner is in cooling operation, the first port 7a is the refrigerant inlet, the second port 7b is the refrigerant outlet, and the third port 7c is the gas or liquid replenishment outlet; when the heat pump air conditioner is in heating operation, the second port 7b is the refrigerant inlet, the first port 7a is the refrigerant outlet, and the third port 7c is the gas or liquid replenishment outlet.

[0083] Furthermore, the controller includes an indoor control mechanism 105 and an outdoor control mechanism 212 that are capable of communicating with each other and controlling the indoor unit 10 and the outdoor unit 20 respectively.

[0084] Further, the indoor control mechanism 105 includes a user information receiving module 1051, a first operation information acquisition module 1052, a first operation status judgment module 1053, a first operation status control module 1054, a first operation status information storage module 1055, a first time statistics module 1056, and a first information sending / receiving module 1057; wherein:

[0085] User information receiving module 1051 is adapted to receive air conditioner operation status setting parameters set by the user;

[0086] The first operation information acquisition module 1052 is adapted to acquire the operation status information of each component in the indoor unit 10.

[0087] The first operating status judgment module 1053 is suitable for judging the operating status of the indoor unit 10 (such as the difference between the indoor temperature and the set temperature, the indoor heating or cooling rate, etc.).

[0088] The first operating status control module 1054 is suitable for controlling the operating status of each component in the indoor unit 10.

[0089] The first operating status information storage module 1055 is adapted to store the operating status information of the indoor unit 10.

[0090] The first-time statistics module 1056 is suitable for calculating the operating time of the indoor unit 10 in various operating modes and operating states.

[0091] The first information sending / receiving module 1057 is adapted to communicate with the outdoor control mechanism 212.

[0092] Furthermore, the outdoor control mechanism 212 includes a second operating status acquisition module 2121, a second operating status judgment module 2122, a second operating status control module 2123, a second operating status information storage module 2124, a second time statistics module 2125, and a second information sending / receiving module 2126; wherein,

[0093] The second operating status acquisition module 2121 is adapted to acquire the operating status information of each component in the outdoor unit 20.

[0094] The second operating status judgment module 2122 is suitable for judging the operating status of the outdoor unit 20 (such as whether the compressor exhaust temperature exceeds the limit).

[0095] The second operating status control module 2123 is suitable for controlling the operating status of each component in the outdoor unit 20.

[0096] The second operating status information storage module 2124 is suitable for storing the operating status information of the outdoor unit 20;

[0097] The second time statistics module 2125 is suitable for statistics of the operating time of the outdoor unit in various operating modes and operating states.

[0098] The second information sending / receiving module 2126 is adapted to communicate with the indoor control mechanism 105. Example 2:

[0099] like Figures 3-7 The cooling operation control method of a gas-injection enthalpy-increasing heat pump air conditioner shown includes the following steps:

[0100] S1: Set D as the first operation mark. The factory default is D=0. D=0 marks the first operation, and D=1 marks a non-first operation. Set the outdoor fan high-speed wind reference power to PRhs.

[0101] When the air conditioner is turned on, the controller receives the operating parameter information set by the user. Let t be a time statistics parameter, and let t=0.

[0102] The controller determines whether the current operating mode is cooling mode. If it is cooling mode, it checks the value of the initial operation marker D.

[0103] If D=0, set the outdoor fan speed to high speed, count the time t, compare the counted time t with the first time judgment threshold a. If t≥a, obtain the current outdoor fan high speed power PRh, set D=1, PRhs=PRh, t=0, and obtain the outdoor ambient temperature To.

[0104] If D=1, directly obtain the outdoor ambient temperature To;

[0105] S2: Set Tdtar to the target compressor exhaust temperature; set P2s to the reference opening degree of the second throttling mechanism in non-replenishment state;

[0106] The controller acquires P2s and Tdtar, causing the first throttling mechanism to operate automatically. The opening degree of the second throttling mechanism P2 is set to P2s. The air conditioner operates automatically according to the set parameters and acquires the compressor discharge temperature Td.

[0107] S3: Compare Td with the exhaust temperature judgment threshold b. If Td≥b, set the outdoor fan speed to the high-speed fan speed Rh, obtain the outdoor fan high-speed power PRh, calculate the actual power judgment coefficient △P=PRh / PRhs, obtain the exhaust temperature correction coefficient △T based on the value of △P, and record the current compressor power Pcom.

[0108] S4: Compare Td with the difference between the preset exhaust temperature judgment threshold b and ΔT, b-ΔT:

[0109] If Td≥b-△T, obtain the compressor frequency F and the second correction coefficient β of the second throttling mechanism opening, and make the first throttling mechanism run automatically. The opening P2 of the second throttling mechanism is adjusted to the product β×P2 of the current opening P2 and the second correction coefficient β of the second throttling mechanism opening.

[0110] If Td < b - △T, obtain the compressor frequency F and the first correction coefficient α of the second throttling mechanism opening, and make the first throttling mechanism run automatically. The opening P2 of the second throttling mechanism is adjusted to the product α × P2 of the current opening P2 and the first correction coefficient α of the second throttling mechanism opening.

[0111] S5: Obtain and record the current compressor discharge temperature Td, open the two-way valve, count the time t, compare the counted time t with the preset time judgment threshold d, if t≥d, set t=0, obtain the current compressor power Pcom' and the current discharge temperature Td', calculate the compressor power judgment coefficient △Pcom=Pcom' / Pcom, and calculate the discharge temperature change value △Td=Td-Td';

[0112] S6: Compare the calculated compressor power judgment coefficient ΔPcom with the preset compressor power judgment threshold e:

[0113] If △Pcom≥e, let both the first and second throttling mechanisms maintain their current operating state, and continue to compare the compressor discharge temperature Td with the discharge temperature judgment threshold g. If Td≤g, close the two-way valve and return to S1 to obtain the outdoor ambient temperature To.

[0114] If △Pcom < e, compare △Td with the preset exhaust temperature change judgment threshold f:

[0115] ① If △Td≥f, let both the first and second throttling mechanisms maintain their current operating state, and continue to compare the compressor discharge temperature Td with the discharge temperature judgment threshold g. If Td≤g, close the two-way valve and return to S1 to obtain the outdoor ambient temperature To.

[0116] ② If △Td<f, then compare the compressor exhaust temperature Td with the exhaust temperature judgment threshold g. If Td≤g, close the two-way valve and return to S1 to obtain the outdoor ambient temperature To; if Td>g, return to S3 to set the outdoor fan speed to the high-speed fan speed Rh and obtain the outdoor fan high-speed power PRh.

[0117] Furthermore, in S3, if Td < b, return to S1 to obtain the outdoor ambient temperature To.

[0118] Furthermore, in S5, if t < d, then the time t is counted until t ≥ d.

[0119] Furthermore, in S6, if △Pcom≥e and Td>g, both the first and second throttling mechanisms are kept in their current operating state until Td≤g.

[0120] like Figure 7 The specific control logic of the cooling operation control method for a gas-injection enthalpy-increasing heat pump air conditioner is as follows:

[0121] S1: Start the program, then proceed to step S2;

[0122] S2: Determine whether the air conditioner has received the power-on signal set by the user. If the power-on signal is received, proceed to step S3; otherwise, proceed to step S32.

[0123] S3: Receive the operating parameter information set by the user, set t=0, and then proceed to step S4;

[0124] S4: Determine whether the current operating mode is cooling mode. If the current mode is cooling mode, proceed to step S5; otherwise, proceed to step S32.

[0125] S5: Determine the value of the initial operation marker D. If D=0, proceed to step S6; otherwise, proceed to step S9.

[0126] S6: Set the outdoor fan speed to high speed, record the time t, and then proceed to step S7;

[0127] S7: Compare the statistical time t with the preset time judgment threshold a. If t≥a, proceed to step S8; otherwise, proceed to step S6.

[0128] S8: Obtain the current outdoor fan power PRh, set D=1, PRhs=PRh, t=0, and then proceed to step S9;

[0129] S9: Obtain the outdoor ambient temperature To, and then proceed to step S10;

[0130] S10: Obtain P2s and Tdtar, then proceed to step S11;

[0131] S11: The first throttling mechanism operates automatically, the opening degree P2 of the second throttling mechanism is set to P2s, and then proceed to step S12;

[0132] S12: The air conditioner operates automatically according to the set parameters, and then proceeds to step S13;

[0133] S13: Obtain the compressor discharge temperature Td, and then proceed to step S14;

[0134] S14: Compare Td with the preset exhaust temperature judgment threshold b. If Td≥b, proceed to step S15; otherwise, proceed to step S9.

[0135] S15: Set the outdoor fan speed to the high-speed fan speed Rh, obtain the outdoor fan high-speed power PRh, and then proceed to step S16;

[0136] S16: Calculate △P, obtain △T, record Pcom, and then proceed to step S17;

[0137] S17: Compare Td with the difference b-ΔT between the preset exhaust temperature judgment threshold b and ΔT. If Td≥b-ΔT, proceed to step S18; otherwise, proceed to step S20.

[0138] S18: Obtain the compressor frequency F and the second correction coefficient β of the second throttling mechanism opening, and then proceed to step S19;

[0139] S19: The first throttling mechanism operates automatically, and the opening degree P2 of the second throttling mechanism is adjusted to the product of the current opening degree P2 and the second correction coefficient β of the opening degree of the second throttling mechanism, β×P2, and then proceed to step S22;

[0140] S20: Obtain the compressor frequency F and the first correction coefficient α of the second throttling mechanism opening, and then proceed to step S21;

[0141] S21: The first throttling mechanism operates automatically, and the opening degree P2 of the second throttling mechanism is adjusted to the product of the current opening degree P2 and the first correction coefficient α of the opening degree of the second throttling mechanism, α×P2, and then proceed to step S22.

[0142] S22: Obtain and record the current compressor discharge temperature Td, and then proceed to step S23;

[0143] S23: Open the two-way valve, record the time t, and then proceed to step S24;

[0144] S24: Compare the statistical time t with the preset time judgment threshold d. If t≥d, proceed to step S25; otherwise, proceed to step S23.

[0145] S25: Let t=0, obtain the current compressor power Pcom', obtain the current exhaust temperature Td', calculate the compressor power judgment coefficient △Pcom (△Pcom=Pcom' / Pcom), calculate the exhaust temperature change value △Td (△Td=Td-Td'), and then proceed to step S26;

[0146] S26: Compare the calculated compressor power judgment coefficient △Pcom with the preset compressor power judgment threshold e. If △Pcom≥e, proceed to step S27; otherwise, proceed to step S29.

[0147] S27: Both the first throttling mechanism and the second throttling mechanism maintain their current operating state, and then proceed to step S28;

[0148] S28: Compare the compressor discharge temperature Td with the discharge temperature judgment threshold g. If Td≤g, proceed to step S31; otherwise, proceed to step S27.

[0149] S29: Compare △Td with the preset exhaust temperature change value judgment threshold f. If △Td≥f, proceed to step S27; otherwise, proceed to step S30.

[0150] S30: Compare the compressor discharge temperature Td with the discharge temperature judgment threshold g. If Td≤g, proceed to step S31; otherwise, proceed to step S15.

[0151] S31: Close the two-way valve, and then proceed to step S9;

[0152] S32: End program

[0153] Symbol explanation:

[0154] To: Outdoor ambient temperature, °C;

[0155] Td: Compressor discharge temperature, °C;

[0156] Td': Compressor discharge temperature, °C;

[0157] Tdtar: Target compressor discharge temperature, °C;

[0158] P1: First throttling mechanism opening, step;

[0159] P2: Opening degree of the second throttling mechanism, step;

[0160] P2s: Reference opening degree of the second throttling mechanism in non-replenishment state, step;

[0161] F: Compressor operating frequency, Hz;

[0162] D: First-time operation mark. The factory default is D=0. D=0 marks the first operation, and D=1 marks a non-first operation.

[0163] R: Outdoor fan speed, rpm;

[0164] Rh: High-speed fan speed of outdoor fan, rpm;

[0165] PRh: High-speed wind power of outdoor fan, in W;

[0166] PRhs: Outdoor fan high-speed wind reference power, W;

[0167] Pcom: Current compressor power, W;

[0168] Pcom': Current compressor power, W;

[0169] t: Time statistics parameter, seconds;

[0170] α: First correction factor for the opening degree of the second throttling mechanism;

[0171] β: Second correction factor for the opening degree of the second throttling mechanism;

[0172] a: Preset time threshold, such as a preset to 20s;

[0173] b: Exhaust temperature judgment threshold, such as b preset to 100℃;

[0174] c: Exhaust temperature judgment threshold, such as c preset to 108℃;

[0175] d: Preset time threshold for judgment, such as d preset to 10s;

[0176] e: Compressor power judgment threshold, e is preset to 1.1;

[0177] f: Threshold for judging exhaust temperature change, such as f preset to 1℃;

[0178] g: Exhaust temperature judgment threshold, such as g preset to 97℃;

[0179] △P: Actual power judgment coefficient of the wind turbine, △P=PRh / PRhs

[0180] △T: Exhaust temperature correction factor, °C;

[0181] △Pcom: Compressor power judgment coefficient, △Pcom=Pcom' / Pcom

[0182] △Td: Exhaust temperature change, △Td = Td - Td'

[0183] In this specific embodiment, in response to the problem that existing gas-injection enthalpy-increasing heat pump air conditioners cannot effectively control the amount of gas or liquid injection, the above solution divides the outdoor ambient temperature into multiple control zones and implements different control methods in each control zone.

[0184] During normal refrigeration operation, the unit achieves the required throttling state through two throttling mechanisms: the first and second throttling mechanisms. The second throttling mechanism has a basic operating opening when the unit is not in gas-replenishing operation, and a minimum operating opening when the unit is in gas-replenishing operation. The minimum operating opening for gas-replenishing operation is smaller than the basic operating opening for non-gas-replenishing operation (the throttling degree of the second throttling mechanism is greater in gas-replenishing operation). During gas replenishment, gas-replenishing operation or liquid-replenishing operation can be achieved by adjusting the relative opening of the first and second throttling mechanisms.

[0185] During refrigeration operation, when it is necessary to replenish gas or liquid to reduce the compressor discharge temperature, the lower the compressor frequency (the lower the compressor frequency, the worse the compressor operation is at this time), the more steps the second throttling mechanism closes, and the first throttling mechanism will open simultaneously. After passing through the first throttling mechanism, the refrigerant dryness (the proportion of gaseous refrigerant after passing through the first throttling mechanism) decreases, and the amount of liquid refrigerant contained in the replenished gas also increases. The discharge temperature is quickly reduced by replenishing the gas-liquid two-phase refrigerant.

[0186] When the compressor frequency is high and the compressor operating conditions are not severe (if the discharge temperature is not reduced by lowering the compressor frequency), the discharge temperature can be slightly reduced by adding gaseous refrigerant.

[0187] During normal refrigeration operation, when the unit is not in operation with gas replenishment, the basic opening of the second throttling mechanism in the non-gas replenishment state is related to the compressor operating frequency. The lower the compressor operating frequency, the smaller the basic opening of the second throttling mechanism in the non-gas replenishment state.

[0188] The degree of gas replenishment can be judged by the rate of decrease in exhaust temperature or the proportion of increase in compressor power after entering the gas replenishment operation. When the rate of decrease in exhaust temperature or the proportion of increase in compressor power reaches a certain level, the throttling mechanism maintains the current opening; otherwise, the throttling mechanism continues to adjust.

[0189] During the gas replenishment process, when the exhaust temperature reaches the first gas replenishment temperature, gaseous refrigerant is added to lower the exhaust temperature; when the exhaust temperature reaches the second gas replenishment temperature, liquid refrigerant is added to lower the exhaust temperature.

[0190] The control of gas or liquid replenishment is reflected in the values ​​of α and β. The smaller the values ​​of α and β, the more liquid refrigerant and the less gaseous refrigerant is replenished, and vice versa.

[0191] By comparing the actual operating power of the outdoor fan with the fan power during initial operation, the exhaust temperature for which the air supply control is initiated is adjusted based on the comparison results. During the initial operation, the power of the outdoor fan at high speed can be recorded. This recorded power is the standard operating power of the fan and can be used to correct the exhaust temperature control during subsequent air supply control. This avoids untimely air supply control and exhaust protection shutdowns caused by dirt or blockage in the outdoor heat exchanger.

[0192] When the exhaust temperature drops below a certain value, the gas (liquid) replenishment control is stopped.

[0193] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0194] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. A method for controlling the refrigeration operation of a gas-injection enthalpy-increasing heat pump air conditioner, characterized in that: This includes an air-fuel-injection enthalpy-increasing heat pump air conditioner (1), which includes a controller, an indoor unit (10), and an outdoor unit (20). The indoor unit (10) includes an indoor heat exchanger (101), an indoor ambient temperature sensor (102), an indoor heat exchanger temperature sensor (103), and an indoor fan (104). The outdoor unit (20) includes a compressor (201), a four-way reversing valve (202), an outdoor heat exchanger (203), an outdoor fan (204), a first throttling mechanism (205), a second throttling mechanism (206), a flash tank (207), a two-way valve (208), an exhaust temperature sensor (209), an outdoor ambient temperature sensor (210), and an outdoor heat exchanger temperature sensor (211). The indoor unit (10) and the outdoor unit (20) form a circuit through the first refrigerant connection pipe (30) and the second refrigerant connection pipe (40); The flash tank (207) has a first port (7a), a second port (7b), and a third port (7c). The first port (7a) is located near the bottom of the flash tank (207), the second port (7b) is located near the bottom of the flash tank (207), and the third port (7c) is located near the top of the flash tank (207). The compressor (201) has a gas supply port (1a). The first port (7a) is connected to the outdoor heat exchanger (203). Furthermore, the outdoor heat exchanger (203) and the first port (7a) are provided with the first throttling mechanism (205); the second port (7b) is connected to the indoor heat exchanger (101) through the first refrigerant connection pipe (30), and the first refrigerant connection pipe (30) is provided with the second throttling mechanism (206); the third port (7c) is connected to the air supply port (1a), and the pipe between the third port (7c) and the air supply port (1a) is provided with the two-way valve (208). When the heat pump air conditioner is in cooling operation, the first pipe port (7a) is the refrigerant inlet, the second pipe port (7b) is the refrigerant outlet, and the third pipe port (7c) is the gas or liquid replenishment outlet; when the heat pump air conditioner is in heating operation, the second pipe port (7b) is the refrigerant inlet, the first pipe port (7a) is the refrigerant outlet, and the third pipe port (7c) is the gas or liquid replenishment outlet. The refrigeration operation control method includes the following steps: S1: Set D as the first operation mark. The factory default is D=0. D=0 marks the first operation, and D=1 marks a non-first operation. Set the outdoor fan high-speed wind reference power to PRhs. When the air conditioner is turned on, the controller receives the operating parameter information set by the user. Let t be a time statistics parameter, and let t=0. The controller determines whether the current operating mode is cooling mode. If it is cooling mode, it checks the value of the initial operation marker D. If D=0, set the outdoor fan speed to high speed, count the time t, compare the counted time t with the first time judgment threshold a. If t≥a, obtain the current outdoor fan high speed power PRh, set D=1, PRhs=PRh, t=0, and obtain the outdoor ambient temperature To. If D=1, directly obtain the outdoor ambient temperature To; S2: Set Tdtar to the target compressor exhaust temperature; P2s is set as the reference opening degree of the second throttling mechanism in the non-replenishment state; The controller acquires P2s and Tdtar, causing the first throttling mechanism to operate automatically. The opening degree of the second throttling mechanism P2 is set to P2s. The air conditioner operates automatically according to the set parameters and acquires the compressor discharge temperature Td. S3: Compare Td with the exhaust temperature judgment threshold b. If Td≥b, set the outdoor fan speed to the high-speed fan speed Rh, obtain the outdoor fan high-speed power PRh, calculate the actual power judgment coefficient △P=PRh / PRhs, obtain the exhaust temperature correction coefficient △T based on the value of △P, and record the current compressor power Pcom. S4: Compare Td with the difference between the preset exhaust temperature judgment threshold b and ΔT, b-ΔT: If Td≥b-△T, obtain the compressor frequency F and the second correction coefficient β of the second throttling mechanism opening, and make the first throttling mechanism run automatically. The opening P2 of the second throttling mechanism is adjusted to the product β×P2 of the current opening P2 and the second correction coefficient β of the second throttling mechanism opening. If Td < b - △T, obtain the compressor frequency F and the first correction coefficient α of the second throttling mechanism opening, and make the first throttling mechanism run automatically. The opening P2 of the second throttling mechanism is adjusted to the product α × P2 of the current opening P2 and the first correction coefficient α of the second throttling mechanism opening. S5: Obtain and record the current compressor discharge temperature Td, open the two-way valve, count the time t, compare the counted time t with the preset time judgment threshold d, if t≥d, set t=0, obtain the current compressor power Pcom' and the current discharge temperature Td', calculate the compressor power judgment coefficient △Pcom=Pcom' / Pcom, and calculate the discharge temperature change value △Td=Td-Td'; S6: Compare the calculated compressor power judgment coefficient ΔPcom with the preset compressor power judgment threshold e: If △Pcom≥e, let both the first and second throttling mechanisms maintain their current operating state, and continue to compare the compressor discharge temperature Td with the discharge temperature judgment threshold g. If Td≤g, close the two-way valve and return to S1 to obtain the outdoor ambient temperature To. If △Pcom < e, compare △Td with the preset exhaust temperature change judgment threshold f: ① If △Td≥f, let both the first and second throttling mechanisms maintain their current operating state, and continue to compare the compressor discharge temperature Td with the discharge temperature judgment threshold g. If Td≤g, close the two-way valve and return to S1 to obtain the outdoor ambient temperature To. ② If △Td<f, then compare the compressor exhaust temperature Td with the exhaust temperature judgment threshold g. If Td≤g, close the two-way valve and return to S1 to obtain the outdoor ambient temperature To; if Td>g, return to S3 to set the outdoor fan speed to the high-speed fan speed Rh and obtain the outdoor fan high-speed power PRh.

2. The method for controlling the refrigeration operation of a gas-injection enthalpy-increasing heat pump air conditioner according to claim 1, characterized in that: In S3, if Td < b, return to S1 to obtain the outdoor ambient temperature To.

3. The method for controlling the refrigeration operation of a gas-injection enthalpy-increasing heat pump air conditioner according to claim 1, characterized in that: In S5, if t < d, then continue to count time t until t ≥ d.

4. The method for controlling the refrigeration operation of a gas-injection enthalpy-increasing heat pump air conditioner according to claim 1, characterized in that: In S6, if △Pcom≥e and Td>g, let both the first and second throttling mechanisms maintain their current operating state until Td≤g.

5. The method for controlling the refrigeration operation of a gas-injection enthalpy-increasing heat pump air conditioner according to claim 1, characterized in that: The controller includes an indoor control mechanism (105) and an outdoor control mechanism (212) that are capable of communicating with each other and controlling the indoor unit (10) and the outdoor unit (20) respectively.

6. The method for controlling the refrigeration operation of a gas-injection enthalpy-increasing heat pump air conditioner according to claim 5, characterized in that: The indoor control mechanism (105) includes a user information receiving module (1051), a first operation information acquisition module (1052), a first operation status judgment module (1053), a first operation status control module (1054), a first operation status information storage module (1055), a first time statistics module (1056), and a first information sending / receiving module (1057); wherein: The user information receiving module (1051) is adapted to receive the air conditioner operation status setting parameters set by the user. The first operation information acquisition module (1052) is adapted to acquire the operation status information of each component in the indoor unit (10); The first operating status judgment module (1053) is adapted to judge the operating status of the indoor unit (10). The first operating status control module (1054) is suitable for controlling the operating status of each component in the indoor unit (10). The first operating status information storage module (1055) is suitable for storing the operating status information of the indoor unit (10); The first time statistics module (1056) is suitable for statistics of the operating time of the indoor unit (10) in various operating modes and operating states. The first information sending / receiving module (1057) is adapted to communicate with the outdoor control mechanism (212).

7. The method for controlling the refrigeration operation of a gas-injection enthalpy-increasing heat pump air conditioner according to claim 6, characterized in that: The outdoor control mechanism (212) includes a second operating status acquisition module (2121), a second operating status judgment module (2122), a second operating status control module (2123), a second operating status information storage module (2124), a second time statistics module (2125), and a second information sending / receiving module (2126); wherein, The second operating status acquisition module (2121) is adapted to acquire the operating status information of each component in the outdoor unit (20); The second operating status judgment module (2122) is suitable for judging the operating status of the outdoor unit (20); The second operating status control module (2123) is suitable for controlling the operating status of each component in the outdoor unit (20); The second operating status information storage module (2124) is suitable for storing the operating status information of the outdoor unit (20); The second time statistics module (2125) is suitable for calculating the operating time of the outdoor unit in various operating modes and operating states. The second information sending / receiving module (2126) is adapted to communicate with the indoor control mechanism (105).

8. A gas-injection enthalpy-increasing type heat pump air conditioner, characterized in that: The method for controlling the cooling operation of a gas-injection enthalpy-increasing heat pump air conditioner as described in any one of claims 1 to 7 above.

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