CN114396708A - Air conditioner and control method thereof - Google Patents

Air conditioner and control method thereof Download PDF

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Publication number
CN114396708A
CN114396708A CN202210216784.6A CN202210216784A CN114396708A CN 114396708 A CN114396708 A CN 114396708A CN 202210216784 A CN202210216784 A CN 202210216784A CN 114396708 A CN114396708 A CN 114396708A
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CN
China
Prior art keywords
pressure difference
air conditioner
control
condition
compressor
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Pending
Application number
CN202210216784.6A
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Chinese (zh)
Inventor
禹志强
丛辉
刘敬坤
吕振鹏
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Qingdao Hisense Hitachi Air Conditioning System Co Ltd
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Qingdao Hisense Hitachi Air Conditioning System Co Ltd
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Priority to CN202210216784.6A priority Critical patent/CN114396708A/en
Publication of CN114396708A publication Critical patent/CN114396708A/en
Pending legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F11/00—Control or safety arrangements
    • F24F11/30—Control or safety arrangements for purposes related to the operation of the system, e.g. for safety or monitoring
    • F24F11/41—Defrosting; Preventing freezing
    • F24F11/42—Defrosting; Preventing freezing of outdoor units
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F11/00—Control or safety arrangements
    • F24F11/62—Control or safety arrangements characterised by the type of control or by internal processing, e.g. using fuzzy logic, adaptive control or estimation of values
    • F24F11/63—Electronic processing
    • F24F11/64—Electronic processing using pre-stored data
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F11/00—Control or safety arrangements
    • F24F11/62—Control or safety arrangements characterised by the type of control or by internal processing, e.g. using fuzzy logic, adaptive control or estimation of values
    • F24F11/63—Electronic processing
    • F24F11/65—Electronic processing for selecting an operating mode
    • F24F11/67—Switching between heating and cooling modes
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F11/00—Control or safety arrangements
    • F24F11/70—Control systems characterised by their outputs; Constructional details thereof
    • F24F11/72—Control systems characterised by their outputs; Constructional details thereof for controlling the supply of treated air, e.g. its pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F11/00—Control or safety arrangements
    • F24F11/88—Electrical aspects, e.g. circuits
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F11/00—Control or safety arrangements
    • F24F11/89—Arrangement or mounting of control or safety devices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F2140/00—Control inputs relating to system states
    • F24F2140/10—Pressure

Abstract

The invention relates to an air conditioner and a control method thereof, wherein the air conditioner comprises a compressor, a four-way valve, an outdoor heat exchanger, a throttling device and an indoor heat exchanger, the air conditioner comprises a control module, the control module is configured to enter a front pressure difference control stage after acquiring a defrosting instruction in a heating mode, control the four-way valve to reverse to enter a defrosting control stage when a front pressure difference ending condition is met, enter a rear pressure difference control stage when the defrosting ending condition is met, and control the four-way valve to reverse to end defrosting control when the rear pressure difference ending condition is met. The air conditioner performs front pressure difference control after acquiring a defrosting instruction, enters back pressure difference control when meeting defrosting ending conditions, can reduce high-low pressure difference when the four-way valve is switched through the front pressure difference control and the back pressure difference control, has small impact force when the four-way valve is switched when the pressure difference is small, is more stable in the reversing process of the four-way valve, reduces the impact on a unit and prevents damage.

Description

Air conditioner and control method thereof
Technical Field
The invention relates to the technical field of air conditioner defrosting control, in particular to an air conditioner and a control method thereof.
Background
During the heating operation of the air conditioner in winter, the fin heat exchanger of the outdoor unit can frost. After frosting, the heat exchange capacity of the unit is reduced, and the heating capacity and the heating efficiency of the unit are reduced, so that the frosting is needed to be removed to a certain degree. The defrosting is realized by converting a unit heating mode into a refrigerating mode through the conversion of a four-way valve, and heating and defrosting are carried out on a fin heat exchanger of the outdoor unit. After defrosting and frosting, the refrigeration mode needs to be switched back to the heating mode through the conversion of the four-way valve, and heating operation is recovered.
According to the existing defrosting control technology of the air conditioner, a four-way valve is directly switched from a heating state to a cooling state in a defrosting process, and then is directly switched from the cooling state to the heating state after defrosting is finished. In one defrosting process, the four-way valve needs to be switched twice. Before the four-way valve is switched, the pressure difference between the evaporation side and the condensation side of the unit is large, the high pressure and the low pressure are balanced at the switching moment of the four-way valve, then the high pressure and the low pressure are reestablished, and the high pressure and the low pressure are changed violently in the process. The violent changes of high pressure and low pressure in the switching process of the four-way valve can cause the vibration of a unit and the exceeding of the stress of a pipeline, and can cause the damage of the four-way valve, the vibration leakage of the pipeline and the like repeatedly for a long time. Therefore, it is very important to develop a new defrosting control method for air conditioners to improve the reliability of the unit.
Disclosure of Invention
The invention provides an air conditioner and a control method thereof, and solves the technical problems of unit vibration, pipeline stress exceeding and four-way valve damage caused by severe high-low pressure change due to large high-low pressure difference before switching of a four-way valve, high-low pressure balance at the switching moment and reestablishment of high-low pressure after switching in the defrosting process or in the defrosting exiting process of the conventional air conditioner.
In order to achieve the purpose, the invention adopts the following technical scheme:
an air conditioner comprises a compressor, a four-way valve, an outdoor heat exchanger, a throttling device and an indoor heat exchanger, wherein the air conditioner comprises a control module, the control module is configured to enter a front pressure difference control stage after acquiring a defrosting instruction in a heating mode, and when a front pressure difference ending condition is met, the four-way valve is controlled to be reversed to enter a defrosting control stage, and when a defrosting ending condition is met, the four-way valve is controlled to be reversed to end defrosting control.
In some embodiments, the pre-differential pressure end condition and the post-differential pressure end condition comprise any one of:
the first condition is as follows: the high-low pressure difference of the air conditioner meets the condition that delta P is more than or equal to a and less than or equal to b, and the actual frequency of the compressor is more than or equal to H1;
and a second condition: the high-low pressure difference of the air conditioner satisfies b & ltdelta & gt & lt c & gt and the actual frequency of the compressor is less than H3;
and (3) carrying out a third condition: the high-low pressure difference of the air conditioner meets the condition that delta P is more than c, and the actual frequency of the compressor is equal to the minimum frequency and lasts for more than a first set time;
and a fourth condition: the differential pressure control time reaches a second set time;
wherein the first set time is less than the second set time.
In some embodiments, a is any value from 0.3MPa to 0.8 MPa, b is any value from 0.8 MPa to 1.3 MPa, and c is any value from 1.31 MPa to 1.8 MPa.
In some embodiments, in the front pressure difference control phase and the rear pressure difference control phase, the control module is configured to increase the frequency of the compressor at a first rate f1 when the pressure difference between high and low pressures of the air conditioner satisfies Δ P < b, decrease the frequency of the compressor at a second rate f2 when the pressure difference between high and low pressures of the air conditioner satisfies Δ P > c, and control the target frequency of the compressor to be H2 when the pressure difference between high and low pressures of the air conditioner satisfies b ≦ Δ P ≦ c, wherein H1 < H2 < H3.
In some embodiments, the first rate f1 is any value of 0.1Hz/s < f1 < 5Hz/s and the second rate f2 is any value of 0.1Hz/s < f1 < 5 Hz/s.
A control method of an air conditioner comprises a compressor, a four-way valve, an outdoor heat exchanger, a throttling device and an indoor heat exchanger, and comprises the following steps: and in the heating mode, after a defrosting instruction is acquired, the four-way valve enters a front pressure difference control stage, when a front pressure difference ending condition is met, the four-way valve is controlled to change direction to enter a defrosting control stage, when a defrosting ending condition is met, the four-way valve enters a rear pressure difference control stage, and when a rear pressure difference ending condition is met, the four-way valve is controlled to change direction to end defrosting control.
In some embodiments, the pre-differential pressure end condition and the post-differential pressure end condition comprise any one of:
the first condition is as follows: the high-low pressure difference of the air conditioner meets the condition that delta P is more than or equal to a and less than or equal to b, and the actual frequency of the compressor is more than or equal to H1;
and a second condition: the high-low pressure difference of the air conditioner satisfies b & ltdelta & gt & lt c & gt and the actual frequency of the compressor is less than H3;
and (3) carrying out a third condition: the high-low pressure difference of the air conditioner meets the condition that delta P is more than c, and the actual frequency of the compressor is equal to the minimum frequency and lasts for more than a first set time;
and a fourth condition: the differential pressure control time reaches a second set time;
wherein the first set time is less than the second set time.
In some embodiments, a is any value from 0.3MPa to 0.8 MPa, b is any value from 0.8 MPa to 1.3 MPa, and c is any value from 1.31 MPa to 1.8 MPa.
In some embodiments, the front pressure difference control phase and the rear pressure difference control phase are that when the pressure difference between high and low pressures of the air conditioner satisfies Δ P < b, the frequency of the compressor is increased at a first rate f1, when the pressure difference between high and low pressures of the air conditioner satisfies Δ P > c, the frequency of the compressor is decreased at a second rate f2, and when the pressure difference between high and low pressures of the air conditioner satisfies b ≦ Δ P ≦ c, the target frequency for controlling the compressor is H2, wherein H1 < H2 < H3.
In some embodiments, the first rate f1 is any value of 0.1Hz/s < f1 < 5Hz/s and the second rate f2 is any value of 0.1Hz/s < f1 < 5 Hz/s.
Compared with the prior art, the technical scheme of the invention has the following technical effects: the air conditioner comprises a compressor, a four-way valve, an outdoor heat exchanger, a throttling device and an indoor heat exchanger, wherein the air conditioner comprises a control module, the control module is configured to enter a front pressure difference control stage after acquiring a defrosting instruction in a heating mode, control the four-way valve to change direction to enter a defrosting control stage when a front pressure difference finishing condition is met, enter a rear pressure difference control stage when a defrosting finishing condition is met, and control the four-way valve to change direction to finish defrosting control when a rear pressure difference finishing condition is met. The air conditioner performs front pressure difference control after acquiring a defrosting instruction, enters back pressure difference control when meeting defrosting ending conditions, can reduce high-low pressure difference when the four-way valve is switched through the front pressure difference control and the back pressure difference control, has small impact force when the four-way valve is switched when the pressure difference is small, is more stable in the reversing process of the four-way valve, reduces the impact on a unit and prevents damage.
The control method of the air conditioner of the invention is as follows: and in the heating mode, after a defrosting instruction is acquired, the four-way valve enters a front pressure difference control stage, when a front pressure difference ending condition is met, the four-way valve is controlled to change direction to enter a defrosting control stage, when a defrosting ending condition is met, the four-way valve enters a rear pressure difference control stage, and when a rear pressure difference ending condition is met, the four-way valve is controlled to change direction to end defrosting control. The air conditioner performs front pressure difference control after acquiring a defrosting instruction, enters back pressure difference control when meeting defrosting ending conditions, can reduce high-low pressure difference when the four-way valve is switched through the front pressure difference control and the back pressure difference control, has small impact force when the four-way valve is switched when the pressure difference is small, is more stable in the reversing process of the four-way valve, reduces the impact on a unit and prevents damage.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
Fig. 1 is a schematic diagram of a refrigerant cycle of an air conditioner according to an embodiment of the present invention.
Fig. 2 is a schematic block diagram of an air conditioner according to an embodiment of the present invention.
Fig. 3 is a schematic block diagram of an air conditioner according to an embodiment of the present invention.
Fig. 4 is a schematic block diagram of an air conditioner according to an embodiment of the present invention.
Fig. 5 is a schematic block diagram of an air conditioner according to an embodiment of the present invention.
Fig. 6 is a control flowchart of an air conditioner according to an embodiment of the present invention.
Fig. 7 is a control flowchart of an air conditioner according to an embodiment of the present invention.
Fig. 8 is a control flowchart of an air conditioner according to an embodiment of the present invention.
Fig. 9 is a control flowchart of an air conditioner according to an embodiment of the present invention.
Fig. 10 is a control flowchart of an air conditioner according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
In the description of the present application, it is to be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience in describing the present application and simplifying the description, but do not indicate or imply that the referred device or element must have a particular orientation, be constructed in a particular orientation, and be operated, and thus should not be construed as limiting the present application.
The terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present application, "a plurality" means two or more unless otherwise specified.
In the description of the present application, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood in a specific case by those of ordinary skill in the art.
The air conditioner performs a refrigeration cycle of the air conditioner by using a compressor, a condenser, a throttle device, and an evaporator. The refrigeration cycle includes a series of processes involving compression, condensation, expansion, and evaporation, and supplies refrigerant to the air that has been conditioned and heat-exchanged.
The compressor compresses a refrigerant gas in a high-temperature and high-pressure state and discharges the compressed refrigerant gas. The discharged refrigerant gas flows into the condenser. The condenser condenses the compressed refrigerant into a liquid phase, and heat is released to the surrounding environment through the condensation process.
The throttling device expands the liquid-phase refrigerant in a high-temperature and high-pressure state condensed in the condenser into a low-pressure liquid-phase refrigerant. The evaporator evaporates the refrigerant expanded in the expansion valve and returns the refrigerant gas in a low-temperature and low-pressure state to the compressor. The evaporator can achieve a cooling effect by heat-exchanging with a material to be cooled using latent heat of evaporation of a refrigerant. The air conditioner can adjust the temperature of the indoor space throughout the cycle.
The outdoor unit of the air conditioner refers to a portion of a refrigeration cycle including a compressor and an outdoor heat exchanger, the indoor unit of the air conditioner includes an indoor heat exchanger, and the throttling device may be provided in the indoor unit or the outdoor unit.
The indoor heat exchanger and the outdoor heat exchanger serve as a condenser or an evaporator. When the indoor heat exchanger is used as a condenser, the air conditioner is used as a heater in a heating mode, and when the indoor heat exchanger is used as an evaporator, the air conditioner is used as a cooler in a cooling mode.
As shown in FIG. 1, the air conditioner includes a compressor 1, a four-way valve 2, an outdoor heat exchanger 3, and a throttle device
4 and an indoor heat exchanger 5.
The air conditioner switches the flow direction of the refrigerant through the four-way valve 2 so as to be in a heating mode or a cooling mode.
When the air conditioner is in a heating mode, the flow direction of the refrigerant in the air conditioner is as follows: compressor 1-four-way valve 2-indoor heat exchanger 5-throttling device 4-outdoor heat exchanger 3-four-way valve 1-compressor 1.
When the air conditioner is in a refrigeration mode, the flow direction of a refrigerant in the air conditioner is as follows: the system comprises a compressor 1, a four-way valve 2, an outdoor heat exchanger 3, a throttling device 4, an indoor heat exchanger 5, a four-way valve 1 and the compressor 1.
When the air conditioner is in a heating mode, because the outdoor heat exchanger 3 is an evaporator, in this case, generally in winter, the outdoor environment temperature is low, the outdoor heat exchanger 3 has a frosting risk, whether the outdoor heat exchanger 3 frosts is detected through the frosting detection module, and a defrosting instruction is generated when the outdoor heat exchanger 3 frosts.
The frosting detection module can be used for detecting whether the outdoor heat exchanger 3 is frosted or not by adopting the prior art, which is not the invention point of the scheme and is not described again here.
As shown in fig. 2, the air conditioner includes a control module configured to enter a front pressure difference control stage after acquiring a defrosting instruction in a heating mode, to enter a defrosting control stage by reversing a four-way valve when a front pressure difference end condition is satisfied, to enter a rear pressure difference control stage when a defrosting end condition is satisfied, and to end defrosting control by reversing the four-way valve when a rear pressure difference end condition is satisfied. According to the scheme, the front pressure difference control is carried out after the defrosting instruction is obtained, the rear pressure difference control is carried out when the defrosting ending condition is met, the high-low pressure difference when the four-way valve is switched can be reduced through the front pressure difference control and the rear pressure difference control, the impact force when the four-way valve is switched is small due to the small pressure difference, the four-way valve is more stable in the reversing process, and the impact on a unit and the damage to the unit are reduced.
Specifically, in the heating mode of the air conditioner, the four-way valve is in a first conduction state, the frosting detection module acquires whether the outdoor heat exchanger is frosted or not, a defrosting instruction is generated when the outdoor heat exchanger is frosted, the control module is configured to control the air conditioner to enter a front pressure difference control stage after acquiring the defrosting instruction, the compressor frequency is controlled in the front pressure difference control, a high-pressure and low-pressure difference value is adjusted to prepare for switching of the four-way valve, the high-pressure and low-pressure difference value of the air conditioner is controlled to be gradually reduced, when a front pressure difference ending condition is met, the four-way valve is controlled to be reversed to be in a second conduction state, namely, the air conditioner enters the defrosting control stage, the outdoor heat exchanger is switched to be a condenser to melt frosting on the outdoor heat exchanger, the frosting detection module acquires whether the outdoor heat exchanger is defrosted or not, the air conditioner enters a rear pressure difference control stage when the defrosting ending condition is met, and the compressor frequency is controlled in the rear pressure difference control, and adjusting the high-low pressure difference value to prepare for switching of the four-way valve, controlling the high-low pressure difference of the air conditioner to be gradually reduced, controlling the four-way valve to be in a first conduction state by reversing when a rear pressure difference ending condition is met, ending the defrosting control, and switching to a heating mode. The above, the primary defrosting control is completed.
The front pressure difference end condition and the rear pressure difference end condition include any one of the following conditions:
the first condition is as follows: the high-low pressure difference of the air conditioner meets the condition that delta P is more than or equal to a and less than or equal to b, and the actual frequency of the compressor is more than or equal to H1;
and a second condition: the high-low pressure difference of the air conditioner satisfies b < delta P < c and the actual frequency of the compressor is less than H3;
and (3) carrying out a third condition: the high-low pressure difference of the air conditioner meets the condition that delta P is more than c, and the actual frequency of the compressor is equal to the minimum frequency and lasts for more than a first set time;
and a fourth condition: the differential pressure control time reaches a second set time;
wherein the first set time is less than the second set time.
In some embodiments, the front pressure differential end condition and the rear pressure differential end condition are condition one: the high-low pressure difference of the air conditioner satisfies that a is more than or equal to delta P and less than or equal to b, and the actual frequency of the compressor is more than or equal to H1. As shown in fig. 3, the air conditioner includes a high pressure detection module, a low pressure detection module, and a compressor frequency detection module.
The high pressure detection module detects a high pressure phigh.
The low pressure detection module detects that the low pressure P is low.
High-low pressure difference Δ P = pwow.
In some embodiments, the front pressure differential end condition and the rear pressure differential end condition are condition two: the high-low pressure difference of the air conditioner satisfies b < delta P < c and the actual frequency of the compressor is less than H3; as shown in fig. 3, the air conditioner includes a high pressure detection module, a low pressure detection module, and a compressor frequency detection module.
The high pressure detection module detects a high pressure phigh.
The low pressure detection module detects that the low pressure P is low.
High-low pressure difference Δ P = pwow.
In some embodiments, the front and rear pressure differential end conditions are condition three: the high-low pressure difference of the air conditioner meets the condition that delta P is more than c, and the actual frequency of the compressor is equal to the minimum frequency and lasts for more than a first set time; as shown in fig. 4, the air conditioner includes a high pressure detection module, a low pressure detection module, a compressor frequency detection module, and a timer.
The high pressure detection module detects a high pressure phigh.
The low pressure detection module detects that the low pressure P is low.
High-low pressure difference Δ P = pwow.
The timer is used to equal the minimum frequency duration for the compressor actual frequency.
In some embodiments, the front pressure differential end condition and the rear pressure differential end condition are condition four: the differential pressure control time reaches a second set time; as shown in fig. 5, the air conditioner includes a high pressure detection module, a low pressure detection module, and a timer.
A test module and a timer.
The high pressure detection module detects a high pressure phigh.
The low pressure detection module detects that the low pressure P is low.
High-low pressure difference Δ P = pwow.
The timer is used for timing the differential pressure control time.
Wherein a is an arbitrary value of 0.3MPa to 0.8 MPa, b is an arbitrary value of 0.8 MPa to 1.3 MPa, and c is an arbitrary value of 1.31 MPa to 1.8 MPa.
In the front pressure difference control stage and the rear pressure difference control stage, the control module is configured to increase the frequency of the compressor at a first rate f1 when the high-low pressure difference of the air conditioner satisfies that delta P is less than b, decrease the frequency of the compressor at a second rate f2 when the high-low pressure difference of the air conditioner satisfies that delta P is greater than c, and control the target frequency of the compressor to be H2 when the high-low pressure difference of the air conditioner satisfies that b is less than or equal to delta P is less than or equal to c, wherein H1 is less than H2 and H3.
Wherein the first speed f1 is any value of 0.1Hz/s < f1 < 5Hz/s, and the second speed f2 is any value of 0.1Hz/s < f1 < 5 Hz/s.
In some embodiments, in the heating mode of the air conditioner, the four-way valve is in a first conduction state, the frost formation detection module acquires whether the outdoor heat exchanger is frosted, and generates a defrosting instruction when the outdoor heat exchanger is frosted, the control module is configured to acquire the defrosting instruction and then control the air conditioner to enter a front pressure difference control stage, when the high-low pressure difference of the air conditioner satisfies delta P > c, the frequency of the compressor is reduced at a second rate f2, when the high-low pressure difference of the air conditioner satisfies b < delta P < c, the target frequency of the compressor is controlled to be H2, so that the high-low pressure difference of the air conditioner is controlled to be gradually reduced, when a front pressure difference ending condition (condition one or condition two or condition three or condition four) is satisfied, the four-way valve is controlled to be in a second conduction state, that is, the air conditioner enters the defrosting control stage, the outdoor heat exchanger is switched to be a condenser, so as to melt the frost formation on the outdoor heat exchanger, the defrosting detection module acquires whether the outdoor heat exchanger finishes defrosting, enters a post-pressure difference control stage when the defrosting finish condition is met, when the high-pressure and low-pressure difference of the air conditioner meets delta P & gt c, the frequency of the compressor is reduced at a second speed f2, when the high-pressure and low-pressure difference of the air conditioner meets b & ltSUB & gt & ltSUB & gt & lt/SUB & gt c & ltSUB & gt & ltSUB & lt & gt & lt & gt & lt & gt & lt & gt & lt & gt & lt & gt & lt/L & gt & lt & gt & lt/L & gt & lt & gt & lt/L & gt & lt & gt & lt & gt & lt/L & gt & lt/L & gt & lt/L & gt & lt/L & gt & lt/L & gt & lt/L & gt &. The above, the primary defrosting control is completed.
A control method of an air conditioner comprises the following steps: and in the heating mode, after a defrosting instruction is acquired, the front pressure difference control stage is started, when the front pressure difference ending condition is met, the four-way valve is controlled to change direction to start the defrosting control stage, when the defrosting ending condition is met, the rear pressure difference control stage is started, when the rear pressure difference ending condition is met, the four-way valve is controlled to change direction to end the defrosting control. According to the scheme, the front pressure difference control is carried out after the defrosting instruction is obtained, the rear pressure difference control is carried out when the defrosting ending condition is met, the high-low pressure difference when the four-way valve is switched can be reduced through the front pressure difference control and the rear pressure difference control, the impact force when the four-way valve is switched is small due to the small pressure difference, the four-way valve is more stable in the reversing process, and the impact on a unit and the damage to the unit are reduced.
As shown in fig. 6, the control method includes the steps of:
and S1, starting.
And S2, acquiring a defrosting control command.
S3, and a front pressure difference control stage.
And S4, meeting the front pressure difference ending condition.
And S5, reversing by the four-way valve.
S6, defrosting control phase.
And S7, meeting the defrosting ending condition.
S8, and a post differential pressure control stage.
And S9, meeting the rear differential pressure ending condition.
And S10, finishing defrosting, and reversing the four-way valve. A heating mode is entered.
Specifically, in the heating mode of the air conditioner, the four-way valve is in a first conduction state to acquire whether an outdoor heat exchanger is frosted or not, a defrosting instruction is generated when the outdoor heat exchanger is frosted, the air conditioner is controlled to enter a front pressure difference control stage after the defrosting instruction is acquired, the frequency of a compressor is controlled in the front pressure difference control, a high-pressure and low-pressure difference value is adjusted to prepare for switching of the four-way valve, the high-pressure and low-pressure difference value of the air conditioner is controlled to be gradually reduced, when a front pressure difference ending condition is met, the four-way valve is controlled to be in a second conduction state in a reversing mode, namely, the air conditioner enters the defrosting control stage, the outdoor heat exchanger is switched to a condenser to melt frosting on the outdoor heat exchanger to acquire whether the defrosting of the outdoor heat exchanger is ended or not, when a defrosting ending condition is met, the rear pressure difference control stage is performed in the rear pressure difference control to control the frequency of the compressor, and the high-low-pressure difference value is adjusted, and preparing for switching the four-way valve, controlling the high-low pressure difference of the air conditioner to be gradually reduced, controlling the four-way valve to be in a first conduction state when a rear pressure difference ending condition is met, ending the defrosting control, and switching to a heating mode. The above, the primary defrosting control is completed.
The front pressure difference end condition and the rear pressure difference end condition include any one of the following conditions:
the first condition is as follows: the high-low pressure difference of the air conditioner meets the condition that delta P is more than or equal to a and less than or equal to b, and the actual frequency of the compressor is more than or equal to H1;
and a second condition: the high-low pressure difference of the air conditioner satisfies b < delta P < c and the actual frequency of the compressor is less than H3;
and (3) carrying out a third condition: the high-low pressure difference of the air conditioner meets the condition that delta P is more than c, and the actual frequency of the compressor is equal to the minimum frequency and lasts for more than a first set time;
and a fourth condition: the differential pressure control time reaches a second set time;
wherein the first set time is less than the second set time.
Wherein a is an arbitrary value of 0.3MPa to 0.8 MPa, b is an arbitrary value of 0.8 MPa to 1.3 MPa, and c is an arbitrary value of 1.31 MPa to 1.8 MPa.
The front differential pressure control stage and the rear differential pressure control stage are as follows: when the high-low pressure difference of the air conditioner meets the requirement that delta P is less than b, the frequency of the compressor is increased at a first speed f1, when the high-low pressure difference of the air conditioner meets the requirement that delta P is more than c, the frequency of the compressor is decreased at a second speed f2, and when the high-low pressure difference of the air conditioner meets the requirement that delta P is more than or equal to b and less than or equal to c, the target frequency of the compressor is controlled to be H2, wherein H1 is more than H2 and more than H3.
Wherein the first speed f1 is any value of 0.1Hz/s < f1 < 5Hz/s, and the second speed f2 is any value of 0.1Hz/s < f1 < 5 Hz/s.
In some embodiments, in the heating mode of the air conditioner, the four-way valve is in a first conduction state to acquire whether the outdoor heat exchanger is frosted or not, a defrosting instruction is generated when the outdoor heat exchanger is frosted, the air conditioner is controlled to enter a front pressure difference control stage after the defrosting instruction is acquired, when the high-low pressure difference of the air conditioner meets delta P & gt c, the frequency of the compressor is reduced at a second speed f2, when the high-low pressure difference of the air conditioner meets b & ltltoreq & gt & ltoreq & gtdelta P & ltoreq & gtc, the target frequency of the compressor is controlled to be H2 to control the high-low pressure difference of the air conditioner to be gradually reduced, when a front pressure difference end condition (condition one or condition two or condition three or condition four) is met, the four-way valve is controlled to be in a second conduction state in a reversing manner, namely, the air conditioner enters the defrosting control stage, the outdoor heat exchanger is switched to a condenser to melt frosting on the outdoor heat exchanger, the frosting detection module acquires whether the defrosting end of the outdoor heat exchanger, entering a post-pressure difference control stage when a defrosting ending condition is met, when the high-pressure difference and the low-pressure difference of the air conditioner meet delta P & gt c, reducing the frequency of the compressor at a second speed f2, when the high-pressure difference and the low-pressure difference of the air conditioner meet b & ltltoreq & gt & ltDELTA P & gtc & ltltoreq & gt, controlling the target frequency of the compressor to be H2 to control the high-pressure difference and the low-pressure difference of the air conditioner to be gradually reduced, and when the post-pressure difference ending condition (condition one or condition two or condition three or condition four) is met, controlling the four-way valve to be in a first conduction state in a reversing mode, ending the defrosting control, and switching to a heating mode. The above, the primary defrosting control is completed.
In some embodiments, as shown in fig. 7, the control method includes the steps of:
and S1, starting.
And S2, acquiring a defrosting control command.
S3, and a front pressure difference control stage.
When the high-low pressure difference of the air conditioner meets the requirement that delta P is larger than c, the frequency of the compressor is reduced at a second speed f2, and when the high-low pressure difference of the air conditioner meets the requirement that b is larger than or equal to delta P and is smaller than or equal to c, the target frequency of the compressor is controlled to be H2, so that the high-low pressure difference of the air conditioner is controlled to be gradually reduced.
And S4, acquiring the high pressure, the low pressure and the actual frequency of the compressor, and meeting the first condition of the end of the front pressure difference.
The first condition is as follows: the high-low pressure difference of the air conditioner satisfies that a is more than or equal to delta P and less than or equal to b, and the actual frequency of the compressor is more than or equal to H1.
And S5, reversing by the four-way valve.
S6, defrosting control phase.
And S7, meeting the defrosting ending condition.
S8, and a post differential pressure control stage.
When the high-low pressure difference of the air conditioner meets the requirement that delta P is larger than c, the frequency of the compressor is reduced at a second speed f2, and when the high-low pressure difference of the air conditioner meets the requirement that b is larger than or equal to delta P and is smaller than or equal to c, the target frequency of the compressor is controlled to be H2, so that the high-low pressure difference of the air conditioner is controlled to be gradually reduced.
And S9, acquiring the high pressure, the low pressure and the actual frequency of the compressor, and meeting the first pressure difference ending condition.
The first condition is as follows: the high-low pressure difference of the air conditioner satisfies that a is more than or equal to delta P and less than or equal to b, and the actual frequency of the compressor is more than or equal to H1.
And S10, finishing defrosting, and reversing the four-way valve. A heating mode is entered.
In some embodiments, as shown in fig. 8, the control method includes the steps of:
and S1, starting.
And S2, acquiring a defrosting control command.
S3, and a front pressure difference control stage.
When the high-low pressure difference of the air conditioner meets the requirement that delta P is larger than c, the frequency of the compressor is reduced at a second speed f2, and when the high-low pressure difference of the air conditioner meets the requirement that b is larger than or equal to delta P and is smaller than or equal to c, the target frequency of the compressor is controlled to be H2, so that the high-low pressure difference of the air conditioner is controlled to be gradually reduced.
And S4, acquiring the high pressure, the low pressure and the actual frequency of the compressor, and meeting the second condition of the end of the front pressure difference.
And a second condition: the high-low pressure difference of the air conditioner satisfies b < delta P < c and the actual frequency of the compressor is less than H3.
And S5, reversing by the four-way valve.
S6, defrosting control phase.
And S7, meeting the defrosting ending condition.
S8, and a post differential pressure control stage.
When the high-low pressure difference of the air conditioner meets the requirement that delta P is larger than c, the frequency of the compressor is reduced at a second speed f2, and when the high-low pressure difference of the air conditioner meets the requirement that b is larger than or equal to delta P and is smaller than or equal to c, the target frequency of the compressor is controlled to be H2, so that the high-low pressure difference of the air conditioner is controlled to be gradually reduced.
And S9, acquiring high pressure, low pressure and actual frequency of the compressor, and meeting the second pressure difference ending condition.
And a second condition: the high-low pressure difference of the air conditioner satisfies b < delta P < c and the actual frequency of the compressor is less than H3.
And S10, finishing defrosting, and reversing the four-way valve. A heating mode is entered.
In some embodiments, as shown in fig. 9, the control method includes the steps of:
and S1, starting.
And S2, acquiring a defrosting control command.
S3, and a front pressure difference control stage.
When the high-low pressure difference of the air conditioner meets the requirement that delta P is larger than c, the frequency of the compressor is reduced at a second speed f2, and when the high-low pressure difference of the air conditioner meets the requirement that b is larger than or equal to delta P and is smaller than or equal to c, the target frequency of the compressor is controlled to be H2, so that the high-low pressure difference of the air conditioner is controlled to be gradually reduced.
And S4, acquiring the actual frequency of the high pressure, the low pressure and the compressor, and timing by a timer, wherein the three conditions of the end of the front pressure difference are met.
And (3) carrying out a third condition: the high-low pressure difference of the air conditioner satisfies that delta P is more than c, and the actual frequency of the compressor is equal to the minimum frequency for more than a first set time.
And S5, reversing by the four-way valve.
S6, defrosting control phase.
And S7, meeting the defrosting ending condition.
S8, and a post differential pressure control stage.
When the high-low pressure difference of the air conditioner meets the requirement that delta P is larger than c, the frequency of the compressor is reduced at a second speed f2, and when the high-low pressure difference of the air conditioner meets the requirement that b is larger than or equal to delta P and is smaller than or equal to c, the target frequency of the compressor is controlled to be H2, so that the high-low pressure difference of the air conditioner is controlled to be gradually reduced.
And S9, acquiring the actual frequency of the high pressure, the low pressure and the compressor, timing by a timer, and meeting the third condition of ending the pressure difference.
And (3) carrying out a third condition: the high-low pressure difference of the air conditioner satisfies that delta P is more than c, and the actual frequency of the compressor is equal to the minimum frequency for more than a first set time.
And S10, finishing defrosting, and reversing the four-way valve. A heating mode is entered.
In some embodiments, as shown in fig. 10, the control method includes the steps of:
and S1, starting.
And S2, acquiring a defrosting control command.
S3, and a front pressure difference control stage.
When the high-low pressure difference of the air conditioner meets the requirement that delta P is larger than c, the frequency of the compressor is reduced at a second speed f2, and when the high-low pressure difference of the air conditioner meets the requirement that b is larger than or equal to delta P and is smaller than or equal to c, the target frequency of the compressor is controlled to be H2, so that the high-low pressure difference of the air conditioner is controlled to be gradually reduced.
And S4, timing the differential pressure control time by a timer, and meeting the fourth condition of the previous differential pressure ending.
And a fourth condition: the differential pressure control time reaches a second set time.
And S5, reversing by the four-way valve.
S6, defrosting control phase.
And S7, meeting the defrosting ending condition.
S8, and a post differential pressure control stage.
When the high-low pressure difference of the air conditioner meets the requirement that delta P is larger than c, the frequency of the compressor is reduced at a second speed f2, and when the high-low pressure difference of the air conditioner meets the requirement that b is larger than or equal to delta P and is smaller than or equal to c, the target frequency of the compressor is controlled to be H2, so that the high-low pressure difference of the air conditioner is controlled to be gradually reduced.
And S9, timing the differential pressure control time by a timer, and meeting the fourth condition of ending the differential pressure.
And a fourth condition: the differential pressure control time reaches a second set time.
And S10, finishing defrosting, and reversing the four-way valve. A heating mode is entered.
According to the scheme, the control mode of the defrosting process of the variable frequency air conditioner is optimized, and the defrosting control process is divided into three stages of front pressure difference, defrosting middle pressure difference and defrosting rear pressure difference. The high-low pressure difference of the air conditioner before the conversion of the four-way valve is adjusted to the optimal operation range by controlling the frequency and the duration time of the compressor at the front pressure difference stage and the rear pressure difference stage, so that the conversion process of the four-way valve is stable, the impact on a unit is reduced, and the damage is prevented.
The solution provided by the scheme has wide applicability, and parameters can be flexibly changed according to the actual condition of the unit.
The control idea of the scheme can be expanded to the application of the constant-speed compressor, and the defrosting control process of the constant-speed compressor can still be divided into three stages of front pressure difference, defrosting neutralization and rear pressure difference. In the stage of front pressure difference and rear pressure difference, the operation of the compressor can be stopped in the stage of front pressure difference and rear pressure difference to reduce the high-low pressure difference when the four-way valve is switched, so that the switching process is stable.
The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims (10)

1. The air conditioner comprises a compressor, a four-way valve, an outdoor heat exchanger, a throttling device and an indoor heat exchanger and is characterized by comprising a control module, wherein the control module is configured to enter a front pressure difference control stage after acquiring a defrosting instruction in a heating mode, control the four-way valve to change direction to enter the defrosting control stage when a front pressure difference finishing condition is met, enter a rear pressure difference control stage when the defrosting finishing condition is met, control the four-way valve to change direction to finish defrosting control when the rear pressure difference finishing condition is met.
2. The air conditioner according to claim 1, wherein the front pressure difference end condition and the rear pressure difference end condition include any one of the following conditions:
the first condition is as follows: the high-low pressure difference of the air conditioner meets the condition that delta P is more than or equal to a and less than or equal to b, and the actual frequency of the compressor is more than or equal to H1;
and a second condition: the high-low pressure difference of the air conditioner satisfies b & ltdelta & gt & lt c & gt and the actual frequency of the compressor is less than H3;
and (3) carrying out a third condition: the high-low pressure difference of the air conditioner meets the condition that delta P is more than c, and the actual frequency of the compressor is equal to the minimum frequency and lasts for more than a first set time;
and a fourth condition: the differential pressure control time reaches a second set time;
wherein the first set time is less than the second set time.
3. The air conditioner according to claim 2, wherein a is any value of 0.3MPa to 0.8 MPa, b is any value of 0.8 MPa to 1.3 MPa, and c is any value of 1.31 MPa to 1.8 MPa.
4. The air conditioner as claimed in claim 2, wherein in the front and rear pressure difference control stages, the control module is configured to increase the frequency of the compressor at a first rate f1 when the pressure difference between high and low pressures of the air conditioner satisfies Δ P < b, decrease the frequency of the compressor at a second rate f2 when the pressure difference between high and low pressures of the air conditioner satisfies Δ P > c, and control the target frequency of the compressor to be H2 when the pressure difference between high and low pressures of the air conditioner satisfies b ≦ Δ P ≦ c, wherein H1 < H2 < H3.
5. The air conditioner as claimed in claim 4, wherein the first rate f1 is any value of 0.1Hz/s < f1 < 5Hz/s, and the second rate f2 is any value of 0.1Hz/s < f1 < 5 Hz/s.
6. A control method of an air conditioner comprises a compressor, a four-way valve, an outdoor heat exchanger, a throttling device and an indoor heat exchanger, and is characterized in that the control method of the air conditioner comprises the following steps: and in the heating mode, after a defrosting instruction is acquired, the four-way valve enters a front pressure difference control stage, when a front pressure difference ending condition is met, the four-way valve is controlled to change direction to enter a defrosting control stage, when a defrosting ending condition is met, the four-way valve enters a rear pressure difference control stage, and when a rear pressure difference ending condition is met, the four-way valve is controlled to change direction to end defrosting control.
7. The control method of an air conditioner according to claim 1, wherein the front pressure difference end condition and the rear pressure difference end condition include any one of the following conditions:
the first condition is as follows: the high-low pressure difference of the air conditioner meets the condition that delta P is more than or equal to a and less than or equal to b, and the actual frequency of the compressor is more than or equal to H1;
and a second condition: the high-low pressure difference of the air conditioner satisfies b & ltdelta & gt & lt c & gt and the actual frequency of the compressor is less than H3;
and (3) carrying out a third condition: the high-low pressure difference of the air conditioner meets the condition that delta P is more than c, and the actual frequency of the compressor is equal to the minimum frequency and lasts for more than a first set time;
and a fourth condition: the differential pressure control time reaches a second set time;
wherein the first set time is less than the second set time.
8. The method of claim 2, wherein a is 0.3 to 0.8 MPa, b is 0.8 to 1.3 MPa, and c is 1.31 to 1.8 MPa.
9. The air conditioner as claimed in claim 2, wherein the front and rear pressure difference control stages are that a compressor frequency is increased at a first rate f1 when a high-low pressure difference of the air conditioner satisfies Δ P < b, a compressor frequency is decreased at a second rate f2 when the high-low pressure difference of the air conditioner satisfies Δ P > c, and a target frequency for controlling the compressor is H2 when the high-low pressure difference of the air conditioner satisfies b ≦ Δ P ≦ c, wherein H1 < H2 < H3.
10. The control method of an air conditioner according to claim 4, wherein the first rate f1 is any value of 0.1Hz/s < f1 < 5Hz/s, and the second rate f2 is any value of 0.1Hz/s < f1 < 5 Hz/s.
CN202210216784.6A 2022-03-07 2022-03-07 Air conditioner and control method thereof Pending CN114396708A (en)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6244057B1 (en) * 1998-09-08 2001-06-12 Hitachi, Ltd. Air conditioner
CN103968494A (en) * 2013-01-25 2014-08-06 珠海格力电器股份有限公司 Control method of air-conditioning system and air-conditioning system
CN104930637A (en) * 2014-03-18 2015-09-23 珠海格力电器股份有限公司 Four-way valve reversing control method, four-way valve reversing device and air conditioning system
CN110486891A (en) * 2019-08-22 2019-11-22 海信（山东）空调有限公司 A kind of defrosting control method and air conditioner
CN112432404A (en) * 2020-11-04 2021-03-02 珠海格力电器股份有限公司 Defrosting control method and device for heat pump air conditioning unit, controller and air conditioning system

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6244057B1 (en) * 1998-09-08 2001-06-12 Hitachi, Ltd. Air conditioner
CN103968494A (en) * 2013-01-25 2014-08-06 珠海格力电器股份有限公司 Control method of air-conditioning system and air-conditioning system
CN104930637A (en) * 2014-03-18 2015-09-23 珠海格力电器股份有限公司 Four-way valve reversing control method, four-way valve reversing device and air conditioning system
CN110486891A (en) * 2019-08-22 2019-11-22 海信（山东）空调有限公司 A kind of defrosting control method and air conditioner
CN112432404A (en) * 2020-11-04 2021-03-02 珠海格力电器股份有限公司 Defrosting control method and device for heat pump air conditioning unit, controller and air conditioning system

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