A heat pump air conditioner and a defrosting operation control method thereof

Abstract

The present application relates to the technical field of heat pump air conditioners, and particularly relates to a heat pump air conditioner and a defrosting operation control method thereof. The control method can control the heat pump air conditioner to perform frost inhibition operation on the upper half and the lower half of the outdoor heat exchanger in sequence when frost formation on the outdoor heat exchanger is less and indoor heating load is small, and the outdoor ambient temperature is high at this time, thereby removing the frost attached to the surface of the outdoor heat exchanger without stopping the heating operation, and ensuring the thermal comfort of the indoor environment while inhibiting frost formation. In addition, the frost inhibition operation will increase the power consumption of the air conditioner and reduce the operation efficiency of the air conditioner. If the outdoor ambient temperature decreases and the frost inhibition effect cannot be guaranteed during the frost inhibition operation, the air conditioner stops the frost inhibition operation and switches to the normal heating operation mode, thereby avoiding the situation that the frost inhibition effect is poor and the operation efficiency of the air conditioner is reduced, and ensuring the thermal comfort of the indoor environment.

Description

Technical Field

[0001] This invention relates to the field of heat pump air conditioning technology, and in particular to a heat pump air conditioner and its defrosting operation control method. Background Technology

[0002] Heat pump air conditioners have been widely used in people's work and daily life.

[0003] When the outdoor ambient temperature is low, the outdoor heat exchanger of the heat pump air conditioner will frost up during the heating operation. When the frost on the outdoor heat exchanger reaches a certain level, the heat exchange efficiency of the outdoor heat exchanger drops sharply, and at this time, the outdoor heat exchanger needs to be defrosted.

[0004] During the defrosting process of the outdoor heat exchanger of the heat pump air conditioner, the heat pump air conditioner will switch to the cooling operation mode, which is the opposite of the heating operation mode. It uses the high-temperature refrigerant discharged by the compressor to defrost the outdoor heat exchanger. During the defrosting operation, the indoor unit of the heat pump air conditioner stops supplying heat, and the thermal comfort of the indoor environment where the heat pump air conditioner is located cannot be effectively guaranteed. Summary of the Invention

[0005] To address the aforementioned problems, the first objective of this invention is to provide a defrosting operation control method that can delay frost formation or control defrosting based on the frost formation status of the outdoor heat exchanger, thereby solving the problem that the thermal comfort of the indoor environment where the heat pump air conditioner is located cannot be effectively guaranteed during the defrosting operation of existing air conditioners. The second objective of this invention is to provide a heat pump air conditioner with the aforementioned defrosting operation control method.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A defrosting operation control method for a heat pump air conditioner, applied to a heat pump air conditioner including a controller, an indoor unit, and an outdoor unit; characterized in that:

[0008] The indoor unit includes an indoor heat exchanger, an indoor ambient temperature sensor, an indoor fan, and an indoor heat exchanger temperature sensor;

[0009] The outdoor unit includes a compressor, a four-way reversing valve, an outdoor heat exchanger, an outdoor fan, an outdoor throttling mechanism, a first temperature sensor for the outdoor heat exchanger, a second temperature sensor for the outdoor heat exchanger, and an outdoor ambient temperature sensor. The indoor and outdoor heat exchangers form a circuit through a first refrigerant connection pipe and a second refrigerant connection pipe. The compressor and the outdoor throttling mechanism are located in the aforementioned circuit. The four-way reversing valve is used to switch the valve port, enabling the air conditioner to operate in cooling and heating modes. The defrosting operation control method includes the following steps:

[0010] Step 1: The controller receives the operating parameter information set by the user, determines whether the operating mode set by the user is the heating operating mode, and if the operating mode is heating, obtains the set temperature set by the user and updates the set temperature Ts and the indoor ambient temperature Ti.

[0011] Step 2: The air conditioner is operating normally in heating mode. It checks whether the air conditioner has received a shutdown signal. If the air conditioner has received a shutdown signal, it checks whether the outdoor heat exchanger is frosted. If the outdoor heat exchanger is frosted, the controller controls the air conditioner to defrost until defrosting is complete.

[0012] If the air conditioner does not receive a shutdown signal, the controller checks whether the outdoor heat exchanger is slightly frosted. If the outdoor heat exchanger is slightly frosted, it checks whether the data of Ts and Ti satisfy Ts-Ti≤a. If Ts-Ti≤a, it obtains the outdoor ambient temperature To. Let D be the frosting suppression applicability flag. When D=0, it is marked that the current condition is suitable for the frosting suppression control mode. When D=1, it is marked that the current condition is not suitable for the frosting suppression control mode. It checks whether the value of To satisfies To≥b. If To≥b, it sets D=0; if Toa or the outdoor heat exchanger 203 is not slightly frosted, it sets D=1.

[0013] Step 3: The controller determines whether the air conditioner has received a shutdown signal. If the air conditioner has received a shutdown signal, step 2 applies. If no shutdown signal is received, the controller determines whether D equals 0. If D=0, the air conditioner operates in the first anti-frost control mode, the compressor operates at a higher frequency than in the normal heating mode, and the outdoor throttling mechanism has a greater throttling degree than in the normal heating mode. Let t=0.

[0014] If D=1, determine whether the air conditioner needs to defrost. If the air conditioner needs to defrost, it will defrost. If the air conditioner does not need to defrost, or if the defrosting is complete, it will operate normally in heating mode.

[0015] Step 4: The air conditioner operates in the first anti-frost control mode, and obtains the outdoor ambient temperature To. The controller judges whether the value of To satisfies To≥b. If To≥b, it obtains the temperature Tc2 detected by the second temperature sensor of the outdoor heat exchanger and judges whether Tc2 satisfies Tc2≥c. If Tc2≥c, it counts the time t and judges whether the time t satisfies t≥e. If t≥e, the air conditioner operates in the second anti-frost control mode. The compressor operates at a higher frequency than in the normal heating mode, and the throttling degree of the outdoor throttling mechanism is smaller than in the normal heating mode. Let t=0.

[0016] If To < b, let D = 1 and t = 0, the air conditioner will operate in normal heating mode.

[0017] If Tc2 < c or t < e, the controller needs to reacquire the outdoor ambient temperature To and compare it with b;

[0018] Step 5: When the air conditioner is operating in the second anti-frost control mode, the controller obtains the outdoor ambient temperature To and judges whether the value of To satisfies To≥b. If To≥b, the controller obtains the temperature Tc1 detected by the first temperature sensor of the outdoor heat exchanger and judges whether Tc1 satisfies Tc1≥c. If Tc1≥c, the controller counts the time t and judges whether the time t satisfies t≥e. If t≥e, the air conditioner continues to operate in the second anti-frost control mode.

[0019] If Tc1 < c or t < e, the controller needs to reacquire the outdoor ambient temperature To and compare it with b;

[0020] If To < b, let D = 1 and t = 0, the air conditioner will operate in normal heating mode.

[0021] Preferably, in step 1, if the operating mode is not heating, the controller directly determines whether the outdoor heat exchanger needs to be frosted. If not, the control ends; if so, the air conditioner performs defrosting operation.

[0022] 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.

[0023] Preferably, the outdoor heat exchanger is provided with a first interface and a second interface. When the heat pump air conditioner is in heating operation, the refrigerant flows in from the second interface and flows out from the first interface.

[0024] Preferably, the outdoor heat exchanger includes a defrosting section A and a frosting section B. A first temperature sensor of the outdoor heat exchanger is disposed on the side wall of the frosting section B and is suitable for detecting the temperature of the frosting section B. A second temperature sensor of the outdoor heat exchanger is disposed on the side wall of the defrosting section A and is suitable for detecting the temperature of the defrosting section A.

[0025] A heat pump air conditioner, which is applied to the defrosting operation control method of a heat pump air conditioner described in any one of the above.

[0026] In response to the problem that existing air conditioners stop supplying heat to the indoor unit when the outdoor unit is defrosting, thus failing to guarantee the thermal comfort of the indoor environment, the present invention adopts the above-mentioned technical solution, which can delay frost formation or control defrosting according to the frost formation of the outdoor heat exchanger, thereby effectively solving the above problems.

[0027] The heat pump air conditioner of this invention, based on the frosting condition of the outdoor heat exchanger, controls the delay of frosting or defrosting during its heating operation according to the following scheme:

[0028] 1. When the actual indoor temperature is close to the user's target temperature, and the frost layer on the outdoor heat exchanger is not thick, the air conditioner enters the anti-frost operation mode:

[0029] ① Increase the compressor operating frequency to ensure that the indoor unit of the heat pump air conditioner can still provide sufficient heat during the anti-frost operation process;

[0030] ② Increase the throttling degree of the throttling mechanism to increase the superheat of the refrigerant in the outdoor heat exchanger, so that more of the refrigerant in the outdoor heat exchanger is in a superheated state above the freezing point, thus suppressing the frosting operation process and removing some of the frost adhering to the surface of the outdoor heat exchanger.

[0031] ③ After some of the frost adhering to the surface of the outdoor heat exchanger is removed, the heat pump air conditioner ends the anti-frost operation process, reduces the throttling degree of the throttling mechanism (the throttling degree is smaller than before entering the anti-frost operation process), and removes the remaining frost adhering to the outdoor heat exchanger.

[0032] ④ Once the frost adhering to the outdoor heat exchanger is cleaned, the heat pump air conditioner will resume normal heating operation.

[0033] 2. If the actual indoor temperature differs significantly from the target temperature set by the user, or if the frost layer on the outdoor heat exchanger reaches a certain thickness, and if the frost layer thickness has reached the point where defrosting is required, the heat pump air conditioner will enter normal defrosting operation.

[0034] The present invention adopts the above-described solution, and its specific beneficial effects are as follows:

[0035] When there is little frost on the outdoor heat exchanger and the indoor heating load is low, if the outdoor ambient temperature is high, the upper and lower parts of the outdoor heat exchanger can be operated sequentially to suppress frost formation. This removes the frost adhering to the surface of the outdoor heat exchanger without stopping the heating operation, thus suppressing frost formation while ensuring the thermal comfort of the indoor environment. In addition, since suppressing defrost operation increases the power consumption and reduces the operating efficiency of the air conditioner, if the outdoor ambient temperature decreases during the frost suppression operation and the frost suppression effect cannot be guaranteed, the air conditioner will stop the frost suppression operation and switch to normal heating operation mode. This avoids the situation where the frost suppression effect is poor and the air conditioner's operating efficiency is reduced, thereby ensuring the thermal comfort of the indoor environment. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the structure of the heat pump air conditioner involved in this invention.

[0037] Figure 2 This is a schematic diagram illustrating the defrosting effect of the outdoor heat exchanger of the heat pump air conditioner involved in this invention during the process of delaying frosting operation.

[0038] Figure 3 This is a schematic diagram of the control logic during the heating operation of the heat pump air conditioner involved in this invention. Detailed Implementation

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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:

[0044] like Figures 1-2 A heat pump air conditioner 1 is shown, including a controller, an indoor unit 10 and an outdoor unit 20;

[0045] The indoor unit 10 includes an indoor heat exchanger 101, an indoor ambient temperature sensor 102, an indoor fan 103, and an indoor heat exchanger temperature sensor.

[0046] The outdoor unit 20 includes a compressor 201, a four-way reversing valve 202, an outdoor heat exchanger 203, an outdoor fan 204, an outdoor throttling mechanism 205, a first temperature sensor 206 for the outdoor heat exchanger, a second temperature sensor 207 for the outdoor heat exchanger, and an outdoor ambient temperature sensor 208. The indoor heat exchanger 101 and the outdoor heat exchanger 203 form a circuit through a first refrigerant connection pipe 30 and a second refrigerant connection pipe 40. The compressor 201 and the outdoor throttling mechanism 205 are disposed in the above circuit. The four-way reversing valve 202 is used to switch the valve port so that the air conditioner has a cooling mode and a heating mode.

[0047] Furthermore, the controller includes an indoor control mechanism 104 and an outdoor control mechanism 209 that are capable of communicating with each other and controlling the indoor unit 10 and the outdoor unit 20 respectively.

[0048] Furthermore, the outdoor heat exchanger 203 is provided with a first interface 8 and a second interface 9. When the heat pump air conditioner is in heating operation, the refrigerant flows in from the second interface 9 and flows out from the first interface 8.

[0049] Furthermore, the outdoor heat exchanger 203 includes a defrosting section A and a frosting section B. The first temperature sensor 206 of the outdoor heat exchanger is disposed on the side wall of the frosting section B and is adapted to detect the temperature of the frosting section B. The second temperature sensor 207 of the outdoor heat exchanger is disposed on the side wall of the defrosting section A and is adapted to detect the temperature of the defrosting section A. Example 2:

[0050] like Figure 3 The defrosting operation control method of the heat pump air conditioner shown above is as follows:

[0051] Step 1: The controller receives the operating parameter information set by the user, determines whether the operating mode set by the user is the heating operating mode, and if the operating mode is heating, obtains the set temperature set by the user and updates the set temperature Ts and the indoor ambient temperature Ti.

[0052] Step 2: The air conditioner is operating normally in heating mode. It checks whether the air conditioner has received a shutdown signal. If the air conditioner has received a shutdown signal, it checks whether the outdoor heat exchanger 203 is frosted. If the outdoor heat exchanger 203 is frosted, the controller controls the air conditioner to perform defrosting until defrosting is complete.

[0053] If the air conditioner does not receive a shutdown signal, the controller checks whether the outdoor heat exchanger 203 is slightly frosted. If the outdoor heat exchanger 203 is slightly frosted, it checks whether the data of Ts and Ti satisfy Ts-Ti≤a. If Ts-Ti≤a, it obtains the outdoor ambient temperature To. Let D be the frosting suppression applicability flag. When D=0, it is marked that the current condition is suitable for the frosting suppression control mode. When D=1, it is marked that the current condition is not suitable for the frosting suppression control mode. It checks whether the value of To satisfies To≥b. If To≥b, it sets D=0; if Toa or the outdoor heat exchanger 203 is not slightly frosted, it sets D=1.

[0054] Step 3: The controller determines whether the air conditioner has received a shutdown signal. If the air conditioner has received a shutdown signal, step 2 applies. If no shutdown signal is received, the controller determines whether D equals 0. If D=0, the air conditioner operates in the first anti-frost control mode, the compressor 201 operates at a higher frequency than in the normal heating mode, and the outdoor throttling mechanism 205 has a larger throttling degree than in the normal heating mode. Let t=0.

[0055] If D=1, determine whether the air conditioner needs to defrost. If the air conditioner needs to defrost, it will defrost. If the air conditioner does not need to defrost, or if the defrosting is complete, it will operate normally in heating mode.

[0056] Step 4: The air conditioner operates in the first anti-frost control mode, and obtains the outdoor ambient temperature To. The controller judges whether the value of To satisfies To≥b. If To≥b, it obtains the temperature Tc2 detected by the second temperature sensor 207 of the outdoor heat exchanger and judges whether Tc2 satisfies Tc2≥c. If Tc2≥c, it counts the time t and judges whether the time t satisfies t≥e. If t≥e, the air conditioner operates in the second anti-frost control mode. The operating frequency of the compressor 201 is higher than that in the normal heating operation mode, and the throttling degree of the outdoor throttling mechanism 205 is smaller than that in the normal heating operation mode. Let t=0.

[0057] If To < b, let D = 1 and t = 0, the air conditioner will operate in normal heating mode.

[0058] If Tc2 < c or t < e, the controller needs to reacquire the outdoor ambient temperature To and compare it with b;

[0059] Step 5: When the air conditioner is operating in the second anti-frost control mode, the controller obtains the outdoor ambient temperature To and judges whether the value of To satisfies To≥b. If To≥b, the controller obtains the temperature Tc1 detected by the first temperature sensor 206 of the outdoor heat exchanger and judges whether Tc1 satisfies Tc1≥c. If Tc1≥c, the controller counts the time t and judges whether the time t satisfies t≥e. If t≥e, the air conditioner continues to operate in the second anti-frost control mode.

[0060] If Tc1 < c or t < e, the controller needs to reacquire the outdoor ambient temperature To and compare it with b;

[0061] If To < b, let D = 1 and t = 0, the air conditioner will operate in normal heating mode.

[0062] Furthermore, in step 1, if the operating mode is not heating, the controller directly determines whether the outdoor heat exchanger 203 needs to be frosted. If not, the control ends; if so, the air conditioner performs defrosting operation.

[0063] It should be noted that heat pump air conditioners have the following four modes during heating operation:

[0064] ① Normal heating mode: The air conditioner operates automatically according to the operating parameters set by the user.

[0065] ② First anti-frost operation mode: In this mode, the air conditioner still operates in heating mode. The operating frequency of the compressor 201 is higher than that in the normal heating operation mode, and the throttling degree of the outdoor throttling mechanism 205 is greater than that in the normal heating operation mode. In this mode, the refrigerant in the upper part of the outdoor heat exchanger 203 is controlled to be in a state of superheating and above the freezing point. At this time, the upper part of the outdoor heat exchanger 203 is operated to suppress frosting.

[0066] ③ Second anti-frost operation mode. In this mode, the air conditioner still operates in heating mode. The operating frequency of the compressor 201 is higher than that in the normal heating operation mode, and the throttling degree of the outdoor throttling mechanism 205 is smaller than that in the normal heating operation mode. In this mode, the refrigerant in the lower half of the outdoor heat exchanger 203 is controlled to be in a state of superheating and above the freezing point. At this time, the lower half of the outdoor heat exchanger 203 is operated to suppress frosting.

[0067] ④ Defrosting mode: In this mode, the air conditioner stops heating and resumes heating after the defrosting operation is completed.

[0068] Specifically, the defrosting operation control logic described above is as follows:

[0069] Step S0: In step S0, the program starts, and then proceeds to step S1;

[0070] Step S1: In step S1, the air conditioner receives the operating parameter information set by the user, and then proceeds to step S2;

[0071] Step S2: In step S2, it is determined whether the operating mode set by the user is the heating operating mode. If the operating mode is heating, proceed to step S3; otherwise, proceed to step S6.

[0072] Step S3: In step S3, the user-set temperature is obtained and the set temperature Ts and indoor ambient temperature Ti are updated, and then the process proceeds to step S4.

[0073] Step S4: In step S4, the air conditioner operates normally in heating mode, and then proceeds to step S5;

[0074] Step S5: In step S5, it is determined whether the air conditioner has received a shutdown signal. If the air conditioner has received a shutdown signal, proceed to step S6; otherwise, proceed to step S9.

[0075] Step S6: In step S6, it is determined whether the outdoor heat exchanger 203 is frosted. If the outdoor heat exchanger 203 is frosted, proceed to step S7; otherwise, proceed to step S40.

[0076] Step S7: In step S7, the air conditioner performs defrosting operation, and then proceeds to step S8;

[0077] Step S8: In step S8, it is determined whether the outdoor heat exchanger 203 has been defrosted. If defrosting is completed, proceed to step S40; otherwise, proceed to step S7.

[0078] Step S9: In step S9, it is determined whether the outdoor heat exchanger 203 is slightly frosted. If the outdoor heat exchanger 203 is slightly frosted, proceed to step S10; otherwise, proceed to step S14.

[0079] Step S10: In step S10, it is determined whether the data of Ts and Ti satisfy Ts-Ti≤a. If Ts-Ti≤a, proceed to step S11; otherwise, proceed to step S14.

[0080] Step S11: In step S11, the outdoor ambient temperature To is obtained, and then proceed to step S12;

[0081] Step S12: In step S12, it is determined whether the value of To satisfies To≥b. If To≥b, proceed to step S13; otherwise, proceed to step S14.

[0082] Step S13: In step S13, set D=0, and then proceed to step S15;

[0083] Step S14: In step S14, let D=1, and then proceed to step S15;

[0084] Step S15: In step S15, it is determined whether the user has changed the setting parameters of the air conditioner. If the user has changed the setting parameters, proceed to step S1; otherwise, proceed to step S16.

[0085] Step S16: In step S16, it is determined whether the air conditioner has received a shutdown signal. If the air conditioner has received a shutdown signal, proceed to step S6; otherwise, proceed to step S17.

[0086] Step S17: In step S17, it is determined whether D is equal to 0. If D=0, proceed to step S21; otherwise, proceed to step S18.

[0087] Step S18: In step S18, it is determined whether the air conditioner needs to defrost. If the air conditioner needs to defrost, proceed to step S19; otherwise, proceed to step S4.

[0088] Step S19: In step S19, the air conditioner performs defrosting operation, and then proceeds to step S20;

[0089] Step S20: In step S20, it is determined whether the air conditioner has completed the defrosting operation. If the defrosting is completed, proceed to step S4; otherwise, proceed to step S19.

[0090] Step S21: In step S21, the air conditioner operates in the first anti-frost control mode. The operating frequency of the compressor 201 is higher than that in the normal heating operation mode, and the throttling degree of the outdoor throttling mechanism 205 is greater than that in the normal heating operation mode. Let t=0, and then proceed to step S22.

[0091] Step S22: In step S22, the outdoor ambient temperature To is obtained, and then proceed to step S23;

[0092] Step S23: In step S23, it is determined whether the value of To satisfies To≥b. If To≥b, proceed to step S24; otherwise, proceed to step S32.

[0093] Step S24: In step S24, the temperature Tc2 detected by the second temperature sensor 207 of the outdoor heat exchanger is obtained and the process proceeds to step S25;

[0094] Step S25: In step S25, it is determined whether the user has changed the setting parameters of the air conditioner. If the user has changed the setting parameters, proceed to step S1; otherwise, proceed to step S26.

[0095] Step S26: In step S26, it is determined whether the air conditioner has received a shutdown signal. If the air conditioner has received a shutdown signal, proceed to step S6; otherwise, proceed to step S27.

[0096] Step S27: In step S27, it is determined whether the temperature Tc2 detected by the second temperature sensor 207 of the outdoor heat exchanger satisfies Tc2≥c. If Tc2≥c, proceed to step S28; otherwise, proceed to step S22.

[0097] Step S28: In step S28, time t is calculated, and then proceed to step S29;

[0098] Step S29: In step S29, it is determined whether time t satisfies t≥e. If t≥e, proceed to step S30; otherwise, proceed to step S22.

[0099] Step S30: In step S30, the air conditioner operates according to the second anti-frost control mode. The operating frequency of the compressor 201 is higher than that of the normal heating operation mode, and the throttling degree of the outdoor throttling mechanism 205 is smaller than that of the normal heating operation mode. Let t=0, and then proceed to step S31.

[0100] Step S31: In step S31, the outdoor ambient temperature To is obtained, and then proceed to step S33;

[0101] Step S32: In step S32, let D=1, t=0, the air conditioner operates in normal heating mode, and then proceed to step S18;

[0102] Step S33: In step S33, it is determined whether the value of To satisfies To≥b. If To≥b, proceed to step S34; otherwise, proceed to step S32.

[0103] Step S34: In step S34, the temperature Tc1 detected by the first temperature sensor 206 of the outdoor heat exchanger is obtained and the process proceeds to step S35.

[0104] Step S35: In step S35, it is determined whether the user has changed the setting parameters of the air conditioner. If the user has changed the setting parameters, proceed to step S1; otherwise, proceed to step S36.

[0105] Step S36: In step S36, it is determined whether the air conditioner has received a shutdown signal. If the air conditioner has received a shutdown signal, proceed to step S6; otherwise, proceed to step S37.

[0106] Step S37: In step S37, it is determined whether the temperature Tc1 detected by the first temperature sensor 206 of the outdoor heat exchanger satisfies Tc1≥c. If Tc1≥c, proceed to step S38; otherwise, proceed to step S31.

[0107] Step S38: In step S38, time t is calculated, and then proceed to step S39;

[0108] Step S39: In step S39, it is determined whether time t satisfies t≥e. If t≥e, proceed to step S30; otherwise, proceed to step S31.

[0109] Step S40: In step S40, the program ends.

[0110] The symbols are explained as follows: Ts: Set temperature; Ti: Indoor ambient temperature; To: Outdoor ambient temperature; Tc1: Temperature detected by the first temperature sensor 206 of the outdoor heat exchanger; Tc2: Temperature detected by the second temperature sensor 207 of the outdoor heat exchanger; a: Temperature difference judgment threshold, in °C, e.g., a is preset to 3 °C; b: Outdoor ambient temperature judgment temperature data, in °C, e.g., b is preset to 3 °C; c: Frost suppression operation end judgment temperature threshold, in °C, e.g., c is preset to 2 °C; D: Frost suppression applicability flag, D=0 indicates that the current condition is suitable for the frost suppression control mode, D=1 indicates that the current condition is not suitable for the frost suppression control mode; t: Time statistics parameter; e: Time statistics threshold, in seconds, e is preset to 30 seconds.

[0111] In this specific embodiment, the energy-saving heat pump air conditioner has four operating modes: normal heating mode, first anti-frost mode, second anti-frost mode, and defrost mode; wherein,

[0112] Specifically, in normal heating operation mode, the heat pump air conditioner automatically controls the compressor operating frequency and the throttling degree of the throttling mechanism according to the operating parameters set by the user.

[0113] Specifically, in the first anti-frost operation mode or the second anti-frost operation mode, the heat pump air conditioner can adjust the operating frequency of the compressor and the throttling degree of the outdoor throttling mechanism to make the temperature of the refrigerant flowing in the upper half or lower half of the outdoor heat exchanger be in a superheated state above the freezing point.

[0114] Specifically, the anti-frost operation mode can only be entered when the outdoor heat exchanger is slightly frosted, the indoor heating load is small, and the outdoor ambient temperature meets specific conditions.

[0115] Specifically, in the first anti-frost operation mode, the compressor operates at a higher frequency than in the normal heating operation mode under the current environmental conditions; the throttling degree of the outdoor throttling mechanism is greater than that during the conventional heating operation under the current environmental conditions.

[0116] Specifically, the air conditioner can only enter the second anti-frost operation mode after it has been in the first anti-frost operation mode for a period of time.

[0117] Specifically, after the heat pump air conditioner completes the anti-frost operation on the upper part of the outdoor heat exchanger, it enters the second anti-frost operation mode.

[0118] Specifically, in the second anti-frost operation mode, the compressor operates at a higher frequency than in the normal heating operation mode under the current environmental conditions; the throttling degree of the outdoor throttling mechanism is smaller than that during conventional heating operation under the current environmental conditions.

[0119] Specifically, when the air conditioner is in the second anti-frost operation mode and the lower half of the outdoor heat exchanger has completed the anti-frost operation, it can normally exit the second anti-frost operation mode.

[0120] Specifically, when the air conditioner is operating in the first anti-frost mode or the second anti-frost mode, if the outdoor ambient temperature does not meet the conditions for entering the first anti-frost mode or the second anti-frost mode, the air conditioner will immediately exit the anti-frost mode and enter the normal heating mode.

[0121] Therefore, when there is little frost on the outdoor heat exchanger, the indoor heating load is low, and the outdoor ambient temperature is high, this heat pump air conditioner can sequentially perform frost suppression operation on the upper and lower parts of the outdoor heat exchanger. This removes the frost adhering to the surface of the outdoor heat exchanger without stopping heating, thus suppressing frost while ensuring indoor thermal comfort. Furthermore, since frost suppression operation increases the air conditioner's power consumption and reduces its operating efficiency, if the outdoor ambient temperature decreases during the frost suppression operation and the frost suppression effect cannot be guaranteed, the air conditioner will stop frost suppression operation and switch to normal heating operation mode. This avoids situations where frost suppression is ineffective and the air conditioner's operating efficiency is reduced, thereby ensuring indoor thermal comfort.

[0122] 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.

[0123] 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 defrosting operation control method for a heat pump air conditioner, applied to a heat pump air conditioner (1), the heat pump air conditioner (1) comprising a controller, an indoor unit (10) and an outdoor unit (20); characterized in that: The indoor unit (10) includes an indoor heat exchanger (101), an indoor ambient temperature sensor (102), an indoor fan (103), and an indoor heat exchanger temperature sensor; The outdoor unit (20) includes a compressor (201), a four-way reversing valve (202), an outdoor heat exchanger (203), an outdoor fan (204), an outdoor throttling mechanism (205), a first temperature sensor (206) for the outdoor heat exchanger, a second temperature sensor (207) for the outdoor heat exchanger, and an outdoor ambient temperature sensor (208). The indoor heat exchanger (101) and the outdoor heat exchanger (203) form a circuit through a first refrigerant connection pipe (30) and a second refrigerant connection pipe (40). The compressor (201) and the outdoor throttling mechanism (205) are located in the above circuit. The four-way reversing valve (202) is used to switch the valve port so that the air conditioner has a cooling mode and a heating mode. The defrosting operation control method has the following steps: Step 1: The controller receives the operating parameter information set by the user, determines whether the operating mode set by the user is the heating operating mode, and if the operating mode is heating, obtains the set temperature set by the user and updates the set temperature Ts and the indoor ambient temperature Ti. Step 2: The air conditioner is operating normally in heating mode. It is determined whether the air conditioner has received a shutdown signal. If the air conditioner has received a shutdown signal, it is determined whether the outdoor heat exchanger (203) is frosted. If the outdoor heat exchanger (203) is frosted, the controller controls the air conditioner to perform defrosting operation until defrosting is completed. If the air conditioner does not receive a shutdown signal, the controller judges whether the outdoor heat exchanger (203) is slightly frosted. If the outdoor heat exchanger (203) is slightly frosted, it judges whether the data of Ts and Ti satisfy Ts-Ti≤a. If Ts-Ti≤a, it obtains the outdoor ambient temperature To. Let D be the applicability flag for suppressing frost. When D=0, it is marked that the current condition is suitable for the frost suppression control method. When D=1, it is marked that the current condition is not suitable for the frost suppression control method. It judges whether the value of To satisfies To≥b. If To≥b, it sets D=0. If To a or the outdoor heat exchanger 203 does not have slight frost, then let D = 1; Step 3: The controller determines whether the air conditioner has received a shutdown signal. If the air conditioner has received a shutdown signal, step 2 applies. If no shutdown signal is received, the controller determines whether D is equal to 0. If D=0, the air conditioner operates in the first anti-frost control mode. The compressor (201) operates at a higher frequency than in the normal heating mode, and the outdoor throttling mechanism (205) has a larger throttling degree than in the normal heating mode. Let t=0. If D=1, determine whether the air conditioner needs to defrost. If the air conditioner needs to defrost, then the air conditioner will defrost. If the air conditioner does not need to defrost, or if the defrosting process is complete, the air conditioner will operate normally in heating mode. Step 4: The air conditioner operates in the first anti-frost control mode, and obtains the outdoor ambient temperature To. The controller judges whether the value of To satisfies To≥b. If To≥b, it obtains the temperature Tc2 detected by the second temperature sensor (207) of the outdoor heat exchanger, and judges whether Tc2 satisfies Tc2≥c. If Tc2≥c, it counts the time t and judges whether the time t satisfies t≥e. If t≥e, the air conditioner operates in the second anti-frost control mode. The operating frequency of the compressor (201) is higher than that of the normal heating operation mode, and the throttling degree of the outdoor throttling mechanism (205) is smaller than that of the normal heating operation mode. Let t=0. If To < b, let D = 1 and t = 0, the air conditioner will operate in normal heating mode. If Tc2 < c or t < e, the controller needs to reacquire the outdoor ambient temperature To and compare it with b; Step 5: When the air conditioner is operating in the second anti-frost control mode, the controller obtains the outdoor ambient temperature To and judges whether the value of To satisfies To≥b. If To≥b, the controller obtains the temperature Tc1 detected by the first temperature sensor (206) of the outdoor heat exchanger and judges whether Tc1 satisfies Tc1≥c. If Tc1≥c, the controller counts the time t and judges whether the time t satisfies t≥e. If t≥e, the air conditioner continues to operate in the second anti-frost control mode. If Tc1 < c or t < e, the controller needs to reacquire the outdoor ambient temperature To and compare it with b; If To < b, let D = 1 and t = 0, the air conditioner will operate in normal heating mode.

2. The defrosting operation control method for a heat pump air conditioner according to claim 1, characterized in that: In step 1, if the operating mode is not heating, the controller directly determines whether the outdoor heat exchanger (203) needs to be frosted. If not, the control ends; if so, the air conditioner performs defrosting operation.

3. The defrosting operation control method for a heat pump air conditioner according to claim 1, characterized in that: The controller includes an indoor control mechanism (104) and an outdoor control mechanism (209) that are capable of communicating with each other and controlling the indoor unit (10) and the outdoor unit (20) respectively.

4. The defrosting operation control method for a heat pump air conditioner according to claim 1, characterized in that: The outdoor heat exchanger (203) is provided with a first interface (8) and a second interface (9). When the heat pump air conditioner is in heating operation, the refrigerant flows in from the second interface (9) and flows out from the first interface (8).

5. The defrosting operation control method for a heat pump air conditioner according to claim 4, characterized in that: The outdoor heat exchanger (203) includes a defrosting section A and a frosting section B. The first temperature sensor (206) of the outdoor heat exchanger is disposed on the side wall of the frosting section B and is suitable for detecting the temperature of the frosting section B. The second temperature sensor (207) of the outdoor heat exchanger is disposed on the side wall of the defrosting section A and is suitable for detecting the temperature of the defrosting section A.

6. A heat pump air conditioner, characterized in that: The defrosting operation control method for a heat pump air conditioner as described in any one of claims 1 to 5 above.

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