CN116412464A - Multi-split air conditioner - Google Patents
Multi-split air conditioner Download PDFInfo
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- CN116412464A CN116412464A CN202310416378.9A CN202310416378A CN116412464A CN 116412464 A CN116412464 A CN 116412464A CN 202310416378 A CN202310416378 A CN 202310416378A CN 116412464 A CN116412464 A CN 116412464A
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- 238000005057 refrigeration Methods 0.000 claims abstract description 40
- 238000012790 confirmation Methods 0.000 claims description 6
- 230000000694 effects Effects 0.000 description 18
- 239000003507 refrigerant Substances 0.000 description 16
- 238000000034 method Methods 0.000 description 11
- 238000001816 cooling Methods 0.000 description 10
- 238000010586 diagram Methods 0.000 description 9
- 238000010438 heat treatment Methods 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 238000004378 air conditioning Methods 0.000 description 3
- 230000005494 condensation Effects 0.000 description 3
- 238000009833 condensation Methods 0.000 description 3
- 238000007791 dehumidification Methods 0.000 description 3
- 238000001514 detection method Methods 0.000 description 3
- 230000008030 elimination Effects 0.000 description 3
- 238000003379 elimination reaction Methods 0.000 description 3
- 239000007791 liquid phase Substances 0.000 description 3
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 2
- 238000004891 communication Methods 0.000 description 2
- 238000001704 evaporation Methods 0.000 description 2
- 230000008020 evaporation Effects 0.000 description 2
- 230000010354 integration Effects 0.000 description 2
- 238000009825 accumulation Methods 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 238000011217 control strategy Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 230000008092 positive effect Effects 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
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Classifications
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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
- F24F3/00—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems
- F24F3/06—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the arrangements for the supply of heat-exchange fluid for the subsequent treatment of primary air in the room units
- F24F3/065—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the arrangements for the supply of heat-exchange fluid for the subsequent treatment of primary air in the room units with a plurality of evaporators or condensers
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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
- F24F11/49—Control or safety arrangements for purposes related to the operation of the system, e.g. for safety or monitoring ensuring correct operation, e.g. by trial operation or configuration checks
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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
- F24F11/50—Control or safety arrangements characterised by user interfaces or communication
- F24F11/61—Control or safety arrangements characterised by user interfaces or communication using timers
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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
- F24F11/62—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
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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
- F24F11/70—Control systems characterised by their outputs; Constructional details thereof
- F24F11/80—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air
- F24F11/83—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air by controlling the supply of heat-exchange fluids to heat-exchangers
- F24F11/84—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air by controlling the supply of heat-exchange fluids to heat-exchangers using valves
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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
- F24F2110/00—Control inputs relating to air properties
- F24F2110/10—Temperature
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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
- F24F2140/00—Control inputs relating to system states
- F24F2140/10—Pressure
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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
- F24F2140/00—Control inputs relating to system states
- F24F2140/20—Heat-exchange fluid temperature
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]
- Y02B30/70—Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Signal Processing (AREA)
- Physics & Mathematics (AREA)
- Fuzzy Systems (AREA)
- Mathematical Physics (AREA)
- Human Computer Interaction (AREA)
- Air Conditioning Control Device (AREA)
Abstract
The invention discloses a multi-split air conditioner, which comprises an outdoor unit and a plurality of indoor units, wherein the indoor units are connected with the outdoor unit; the indoor unit comprises an indoor heat exchanger and an indoor machine electronic expansion valve; the indoor heat exchanger is connected with the outdoor unit through an internal motor expansion valve; the indoor heat exchanger comprises an inlet and a plurality of elbows; the indoor unit further comprises an indoor unit controller, an inlet temperature sensor, an elbow temperature sensor and an indoor temperature sensor which are connected with the indoor unit controller; the inlet temperature sensor and the elbow temperature sensor are respectively arranged at the inlet and one elbow and used for detecting the inlet temperature, the elbow temperature and the indoor temperature sensor and used for detecting the indoor temperature and transmitting the indoor temperature to the internal machine controller; the internal machine controller is configured to judge whether the internal machine electronic expansion valve is in a limit small opening state according to the inlet temperature, the elbow temperature and the indoor temperature; and if yes, controlling the valve to increase the opening degree; if not, the superheat control is kept executed. The invention detects and controls the opening state of the internal motor electronic expansion valve, and prevents the internal refrigeration from being ineffective.
Description
Technical Field
The invention relates to the technical field of air conditioning, in particular to a multi-connection air conditioner.
Background
In the traditional control of the expansion valve of the internal machine, the throttle degree can be adjusted by controlling the expansion valve of the internal machine to increase the opening degree or decrease the opening degree during refrigeration. As the control quantity increases, the switching error generated by control also increases, and the condition that the opening degree of the expansion valve of the internal machine is not reset due to long-time control is inaccurate, so that the temperature control efficiency is low, and the use experience of a user is influenced; when the opening degree of the expansion valve of the inner machine is smaller, even when the expansion valve of the inner machine is closed to 0 opening degree or the minimum opening degree, the inner machine loses the refrigerating capacity, and the use experience of a user is seriously affected.
In the prior art, whether the opening of the outdoor electronic expansion valve has errors or not is judged through the target exhaust temperature, the exhaust time and the operating frequency of the compressor, and when the errors exist, the air conditioning system is restarted to reset the outdoor electronic expansion valve, so that the use of a user is affected, the detection and the elimination of whether the errors exist in the outdoor electronic expansion valve are only solved, and the detection and the elimination of whether the errors exist in the electronic expansion valves of one or more indoor units in the multi-split air conditioner cannot be solved.
The above information disclosed in this background section is only for enhancement of understanding of the background section of the application and therefore it may not form the prior art that is already known to those of ordinary skill in the art.
Disclosure of Invention
Aiming at the problems pointed out in the background art, the opening state of the electronic expansion valve of the multi-split air conditioner internal machine is detected, a corresponding control strategy is adopted according to the detection condition, the inefficiency of internal machine refrigeration is avoided, the running reliability of the whole machine is improved, and the use experience of a user is improved.
In order to achieve the aim of the invention, the invention is realized by adopting the following technical scheme:
in some embodiments of the present application, a multi-split air conditioner is provided, including an outdoor unit and a plurality of indoor units; the indoor unit comprises an indoor heat exchanger and an indoor machine electronic expansion valve; the indoor heat exchanger is connected with the outdoor unit through the internal machine electronic expansion valve; the indoor heat exchanger comprises an inlet, an outlet and a plurality of elbows;
the indoor unit further comprises an indoor unit controller, an inlet temperature sensor, an elbow temperature sensor and an indoor temperature sensor which are respectively connected with the indoor unit controller; the inlet temperature sensor and the elbow temperature sensor are respectively arranged at the inlet and one of the elbows and used for detecting the inlet temperature and the elbow temperature and transmitting the inlet temperature and the elbow temperature to the internal machine controller; the indoor temperature sensor is used for detecting indoor temperature and transmitting the indoor temperature to the indoor unit controller;
The internal machine controller is configured to judge whether the internal machine electronic expansion valve is in a limit small opening state according to the inlet temperature, the elbow temperature and the indoor temperature; when the internal electronic expansion valve is in a limit small opening state, controlling the internal electronic expansion valve to increase the opening; and when the internal motor expansion valve is not in the limit small opening state, the superheat control is kept to be executed.
In a specific embodiment, the indoor unit further comprises an air suction superheat acquisition device and a pressure sensor, which are arranged on the outdoor unit, are respectively connected with the indoor unit controller, and are used for acquiring the air suction superheat and the low pressure of the outdoor unit and transmitting the air suction superheat and the low pressure to the indoor unit controller;
the internal machine controller is configured with a first temperature limit value, a second temperature limit value, a first opening limit value, a first low-pressure limit value, and a first time period, and is configured to determine whether an opening degree of the internal machine electronic expansion valve is lower than the first opening limit value, whether the low-pressure is lower than the first low-pressure limit value, and whether a difference between the inlet temperature and the suction superheat exceeds the first temperature limit value for the first time period or a difference between the elbow temperature and the suction superheat exceeds the first temperature limit value for the first time period or a difference between the indoor temperature and the second temperature limit value does not exceed the inlet temperature for the first time period or a difference between the indoor temperature and the second temperature limit value does not exceed the elbow temperature for the first time period;
When the conditions are judged to be yes, determining that the internal electronic expansion valve is in the limit small opening state; otherwise, the state is not the limit small opening state.
In a specific embodiment, the internal machine controller is further configured with an operation time limit value, and is configured to accumulate a duration of the refrigeration cycle temperature control mode, determine whether the duration of the refrigeration cycle temperature control mode reaches the operation time limit value or more, and if so, determine whether the internal machine electronic expansion valve is in the limit small opening state.
In a specific embodiment, the indoor unit controller is configured to end the increased opening degree control if the indoor unit ends the refrigeration cycle when executing the increased opening degree control;
and when the indoor unit finishes the refrigeration cycle or is switched to other operation modes, the duration of the refrigeration cycle temperature control mode is cleared.
In some specific embodiments, the internal machine controller is configured with an increased opening, a minimum opening, a second opening limit, a third temperature limit; the initial value of the minimum opening is 0; the second opening limit is greater than the first opening limit; the opening degree increase control includes:
Judging whether the minimum opening is 0; when the valve is 0, the internal electronic expansion valve is controlled to be closed;
after the internal electronic expansion valve is closed, the opening of the internal electronic expansion valve is increased at least once; judging whether the opening of the internal electronic expansion valve exceeds the second opening limit value after increasing the opening every time; if yes, controlling the internal electronic expansion valve to recover the superheat control; if not, judging whether the difference between the elbow temperature before increasing the opening degree and the elbow temperature after increasing the opening degree exceeds the third temperature limit value or whether the difference between the inlet temperature before increasing the opening degree and the inlet temperature after increasing the opening degree exceeds the third temperature limit value, and if so, judging that the internal electronic expansion valve is opened, performing minimum opening degree storage control and recovering the superheat degree control, and if not, controlling the internal electronic expansion valve to continuously increase the opening degree.
In some specific embodiments, the minimum opening degree storage control includes:
judging whether the low pressure is lower than the first low pressure limit value;
If yes, judging whether the current opening of the internal electronic expansion valve exceeds the first opening limit value, and if yes, storing the first opening limit value to the minimum opening and recovering the superheat degree control, and if not, storing the current opening of the internal electronic expansion valve to the minimum opening and recovering the superheat degree control;
if not, directly recovering the superheat control.
In some specific embodiments, the increasing opening degree control further includes:
judging whether the minimum opening is 0; when the opening degree is not 0, controlling the internal electronic expansion valve to be opened to the minimum opening degree;
after the internal electronic expansion valve is opened to the minimum opening, the opening of the internal electronic expansion valve is increased at least once; judging whether the opening of the internal electronic expansion valve exceeds the second opening limit value after increasing the opening every time; if yes, controlling the internal electronic expansion valve to recover the superheat control; if not, judging whether the difference between the elbow temperature before increasing the opening degree and the elbow temperature after increasing the opening degree exceeds the third temperature limit value or whether the difference between the inlet temperature before increasing the opening degree and the inlet temperature after increasing the opening degree exceeds the third temperature limit value, and if yes, judging that the internal motor expansion valve is opened, recovering the superheat degree control, and if not, performing closing confirmation judgment and control of the internal motor expansion valve.
In some specific embodiments, the determining and controlling of the closing confirmation of the internal electronic expansion valve includes:
judging whether the difference between the indoor temperature and the second temperature limit exceeds the inlet temperature and whether the difference between the indoor temperature and the second temperature limit exceeds the elbow temperature;
and if so, the internal electronic expansion valve resumes the superheat control, and if not, the opening degree of the internal electronic expansion valve is controlled to be continuously increased by the increased opening degree.
In some specific embodiments, the internal controller is configured with a second pressure limit that is less than the first pressure limit; the internal machine controller is configured to determine whether the low pressure is lower than the second pressure limit value when the internal machine electronic expansion valve is in the limit small opening state; and when the low pressure is lower than the second pressure limit value, controlling the opening of the internal electronic expansion valve to be increased to the second opening limit value, and recovering the superheat control.
In a specific embodiment, the system further comprises an outlet temperature sensor, which is arranged at the outlet, connected with the internal machine controller and used for detecting the outlet temperature and transmitting the outlet temperature to the internal machine controller; the inner machine controller is also configured with a superheat setting value; and the superheat degree control is to perform suction superheat degree PI control through the difference between the outlet temperature and the inlet temperature and the superheat degree set value, and is used for controlling the opening of the internal electronic expansion valve.
Compared with the prior art, the invention has the advantages and positive effects that:
according to the multi-split air conditioner, whether the indoor unit electronic expansion valve is in the limit small opening state or not is judged by collecting the inlet temperature, the elbow temperature and the indoor temperature of the indoor heat exchanger of the indoor unit, and opening increasing control or overheat maintaining control is carried out according to the judging conditions, so that the problem that the indoor unit is in the refrigeration cycle state and has no refrigeration effect due to the fact that the indoor unit electronic expansion valve is in the limit small opening state in the refrigeration cycle process of the multi-split air conditioner due to the error generated by the temperature control and adjustment of the indoor unit electronic expansion valve is prevented, and the reliability of the refrigeration operation of the multi-split air conditioner and the use experience of users are improved.
Other features and advantages of the present invention will become apparent upon review of the detailed description of the invention in conjunction with the drawings.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions of the prior art, the drawings that are needed in the embodiments or the description of the prior art will be briefly described below, it will be obvious that the drawings in the following description are some embodiments of the present invention, and that other drawings can be obtained according to these drawings without inventive effort to a person skilled in the art.
FIG. 1 is a schematic diagram of a system according to an embodiment;
FIG. 2 is a control component connection schematic according to an embodiment;
FIG. 3 is a control component connection schematic according to another embodiment;
FIG. 4 is a control flow diagram according to an embodiment;
FIG. 5 is a control flow diagram according to an embodiment;
FIG. 6 is a schematic diagram of a decision condition I control flow according to an embodiment;
FIG. 7 is a schematic diagram of an indoor heat exchanger temperature acquisition flow in accordance with an embodiment;
FIG. 8 is a schematic diagram of an indoor heat exchanger temperature acquisition flow scheme according to another embodiment;
fig. 9 is a schematic diagram of a decision condition II control flow according to an embodiment;
FIG. 10 is a schematic diagram of a decision condition III control flow according to an embodiment;
fig. 11 is a schematic diagram of a decision condition IV control flow according to an embodiment.
Reference numerals:
1. an indoor unit; 11. an indoor heat exchanger; 111. an inlet; 112. an elbow; 113. an outlet; 12. an internal electronic expansion valve; 13. an internal machine controller; 14. an inlet temperature sensor; 15. an elbow temperature sensor; 16. an indoor temperature sensor; 2. an outdoor unit; 21. a compressor; 22. An external electronic expansion valve; 23. a pressure sensor; 24. an intake air temperature sensor; 25. and an external machine controller.
Description of the embodiments
The following description of the embodiments of the present application will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all, of the embodiments of the present application. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are within the scope of the present disclosure.
In the description of the present application, it should be understood that the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or an implicit indication of the number of technical features being indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present application, unless otherwise indicated, the meaning of "a plurality" is two or more.
In the description of the present application, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the terms in this application will be understood by those of ordinary skill in the art in a specific context.
The following disclosure provides many different embodiments, or examples, for implementing different features of the invention. In order to simplify the present disclosure, components and arrangements of specific examples are described below. They are, of course, merely examples and are not intended to limit the invention. Furthermore, the present invention may repeat reference numerals and/or letters in the various examples, which are for the purpose of brevity and clarity, and which do not themselves indicate the relationship between the various embodiments and/or arrangements discussed. In addition, the present invention provides examples of various specific processes and materials, but one of ordinary skill in the art will recognize the application of other processes and/or the use of other materials.
The air conditioner performs a refrigerating cycle of the air conditioner by using a compressor, a condenser, an expansion valve, and an evaporator. The refrigeration cycle includes a series of processes involving compression, condensation, expansion, and evaporation, and refrigerating or heating an indoor space.
The low-temperature low-pressure refrigerant enters the compressor, the compressor compresses the refrigerant gas into a high-temperature high-pressure state, and the compressed refrigerant gas is discharged. 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 expansion valve expands the liquid-phase refrigerant in a high-temperature and high-pressure state formed by condensation 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 may achieve a cooling effect by exchanging heat with a material to be cooled using latent heat of evaporation of a refrigerant. The air conditioner may adjust the temperature of the indoor space throughout the cycle.
An outdoor unit of an air conditioner refers to a portion of a refrigeration cycle including a compressor and an outdoor heat exchanger, an indoor unit of the air conditioner includes an indoor heat exchanger, and an expansion valve may be provided in the indoor unit or the outdoor unit.
The indoor heat exchanger and the outdoor heat exchanger function as a condenser or an evaporator. When the indoor heat exchanger is used as a condenser, the air conditioner is used as a heater of a heating mode, and when the indoor heat exchanger is used as an evaporator, the air conditioner is used as a cooler of a cooling mode.
Referring to fig. 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 and 11, the multi-split air conditioner of the present invention includes a plurality of indoor units 1 and outdoor units 2; the outdoor unit 2 includes a compressor 21, a condenser described in the above-described air conditioner principle; the indoor unit 1 includes an indoor heat exchanger 11 corresponding to an evaporator in the air conditioner; the expansion valve in the air conditioner principle description above includes a plurality of internal and external electronic expansion valves 12, 22 in this application.
The indoor heat exchangers 11 of the indoor units 1 are connected to the outdoor unit 2 through the indoor unit motor expansion valves 12 corresponding to the indoor units 1, respectively; that is, the indoor heat exchangers 11 of the indoor units 1 are connected in series with the indoor motor expansion valves 12 of the corresponding indoor units 1, respectively, and then connected to the same refrigerant pipe, and are connected to the condenser of the outdoor unit 2 via the refrigerant pipe; the outer machine electronic expansion valve 22 is arranged on a refrigerant pipe of the outdoor machine 2 and used for throttling the refrigerant; the respective indoor unit electronic expansion valves 12 throttle the refrigerant flowing into the respective indoor heat exchangers 11, thereby ensuring the cooling effect of the respective indoor units 1, and the opening degree of the respective indoor unit electronic expansion valves 12 is controlled to adjust the cooling effect of the respective indoor units 1.
The indoor heat exchanger 11 includes an inlet 111, an outlet 113, and a plurality of elbows 112; the indoor unit 1 further includes an indoor unit controller 13, an inlet temperature sensor 14, an elbow temperature sensor 15, and an indoor temperature sensor 16, which are connected to the indoor unit controller 13, respectively. An inlet temperature sensor 14 and an elbow temperature sensor 15 are respectively arranged at an inlet 111 of the indoor heat exchanger 11 and one elbow 112 of the indoor heat exchanger 11, and are used for detecting the inlet temperature and the elbow temperature of the indoor heat exchanger 11 and transmitting the inlet temperature and the elbow temperature to the indoor unit controller 13; the indoor temperature sensor 16 is used to detect the indoor temperature and transmit it to the indoor unit controller 13.
The internal machine controller 13 is configured to determine whether the internal machine electronic expansion valve 12 is in a limit small opening state according to the received inlet temperature, elbow temperature and indoor temperature; when the internal motor expansion valve 12 is judged to be in the limit small opening state, the internal motor expansion valve 12 is controlled to increase the opening; when it is determined that the internal motor expansion valve 12 is not in the limit small opening state, the superheat control is continued for the opening of the internal motor expansion valve 12.
That is, during the refrigeration cycle, the indoor unit controller 13 of the indoor unit 1 controls the superheat degree of the corresponding indoor unit electronic expansion valve 12. That is, during the refrigeration cycle, the indoor unit controller 13 controls the opening degree of the indoor unit electronic expansion valve 12 in accordance with the suction superheat degree of the outdoor unit 2 so as to achieve the refrigeration capacity for adjusting the temperature in the installation room. The method comprises the steps of receiving the inlet temperature, the elbow temperature and the indoor temperature of the corresponding indoor heat exchanger 11 in the process of performing superheat control on the indoor machine electronic expansion valve 12, judging the state of the indoor machine electronic expansion valve 12 corresponding to the indoor machine 1 according to the received inlet temperature, elbow temperature and indoor temperature, judging whether the state is in a limit small opening state or not, and judging whether the opening control of the indoor machine electronic expansion valve 12 at the moment has errors or not, and whether the existing errors influence the refrigerating effect of the indoor machine 1 or not. Judging the inlet temperature, the elbow temperature and the indoor temperature according to the received judgment, namely judging the judgment condition I; the limit small opening state is a state in which the opening of the indoor unit electronic expansion valve 12 is smaller due to a control error, and the opening of the state makes the indoor unit 1 unable to normally cool. When the internal machine controller 13 judges that the internal machine electronic expansion valve 12 is in the limit small opening state, the corresponding internal machine electronic expansion valve 12 is controlled to increase the opening degree, so that the opening degree of the internal machine electronic expansion valve 12 is increased; when the internal machine controller 13 determines that the internal machine electronic expansion valve 12 is not in the limit small opening state, the superheat control is kept.
The multi-split air conditioner of the invention judges whether the control error of the indoor unit electronic expansion valve 12 of the corresponding indoor unit 1 has affected the refrigerating effect of the indoor unit 1 by collecting the inlet temperature and the elbow temperature of the indoor heat exchanger 11 of the corresponding indoor unit 1 and the indoor temperature of the corresponding indoor unit 1 and by the inlet temperature, the elbow temperature and the indoor temperature of the corresponding indoor unit 1. When the control error of the internal machine electronic expansion valve 12 has affected the refrigerating effect of the indoor machine 1, the corresponding internal machine electronic expansion valve 12 is controlled to execute opening degree increasing control, so that the refrigerating effect is prevented from being reduced due to the control error of the internal machine electronic expansion valve 12, and the use experience of a user is improved; according to the invention, the accuracy of the temperature judgment at the inlet of the indoor heat exchanger 11 is ensured through mutual evidence judgment or alternative judgment of the inlet temperature and the elbow temperature, so that the accuracy of the opening state judgment of the internal motor expansion valve 12 is improved; the accuracy of judging the opening state of the internal electronic expansion valve 12 is further ensured through the supplementary judgment of the indoor temperature; and when the opening degree is increased, the refrigerating effect of the indoor unit 1 is ensured, the running reliability of the multi-split air conditioner is improved, and the use experience of a user is improved.
The control and principle of the multi-split air conditioner of the invention are described in detail below through specific embodiments.
In a specific embodiment, referring to fig. 1, 2, 3, 5 and 6, the multi-split air conditioner further includes an intake superheat obtaining device and a pressure sensor 23, which are disposed on the outdoor unit 2 and respectively connected to the indoor unit controller 13, and are used for obtaining the intake superheat and the low pressure of the outdoor unit 2 and transmitting the obtained air superheat and low pressure to the indoor unit controller 13.
The internal machine controller 13 is configured with a first temperature limit value, a second temperature limit value, a first opening limit value, a first low pressure limit value, and a first duration, and is configured to determine whether the opening degree of the internal machine electronic expansion valve 12 is lower than the first opening limit value, whether the low pressure is lower than the first low pressure limit value, and whether a difference between the inlet temperature and the suction superheat exceeds the first temperature limit value for the first duration or a difference between the elbow temperature and the suction superheat exceeds the first temperature limit value for the first duration or a difference between the indoor temperature and the second temperature limit value does not exceed the inlet temperature for the first duration or a difference between the indoor temperature and the second temperature limit value does not exceed the elbow temperature for the first duration.
When the indoor unit controller 13 determines that the conditions of the indoor units 1 are yes, determining that the indoor unit electronic expansion valve 12 is in a limit small opening state; otherwise, the state is not in a limit small opening state.
That is, when the internal machine controller 13 determines that the opening degree of the internal machine electronic expansion valve 12 does not exceed the first opening degree limit value, the low pressure does not exceed the first low pressure limit value, and the difference between the inlet temperature and the suction superheat exceeds the first temperature limit value for the first duration, the difference between the elbow temperature and the suction superheat exceeds the first temperature limit value for the first duration, the difference between the indoor temperature and the second temperature limit value does not exceed the inlet temperature for the first duration, and the difference between the indoor temperature and the second temperature limit value does not exceed the elbow temperature for any one or more of four determinations of the first duration are established, the internal machine electronic expansion valve 12 is determined to be in the limit small opening state. Otherwise, when the internal machine controller 13 determines that the opening degree of the internal machine electronic expansion valve 12 exceeds the first opening degree limit value and the low pressure exceeds any one or two of the first low pressure limit values, it is determined that the internal machine electronic expansion valve 12 is not in the limit small opening state; or the internal motor expansion valve 12 is not in the limit small opening state when all of the four determinations including the difference between the inlet temperature and the suction superheat exceeding the first temperature limit for the first duration, the difference between the elbow temperature and the suction superheat exceeding the first temperature limit for the first duration, the difference between the indoor temperature and the second temperature limit not exceeding the inlet temperature for the first duration, and the difference between the indoor temperature and the second temperature limit not exceeding the elbow temperature for the first duration are not satisfied.
The first opening limit value is the minimum opening of the internal motor expansion valve 12 at the time of superheat control.
The multi-split air conditioner of the embodiment makes the judgment of the state of the limit small opening degree of the internal machine electronic expansion valve 12 more accurate and has no missing condition by judging the relation between the difference value of the inlet temperature, the elbow temperature and the air suction superheat degree and the set first temperature limit value and by complementarily judging the state of the internal machine electronic expansion valve 12 by the relation between the indoor temperature and the inlet temperature and the relation between the indoor temperature and the elbow temperature, ensures the refrigerating effect of the indoor machine 1 and improves the use experience of users.
Of course, the intake superheat and the low pressure can be obtained by the internal controller 13 via the external controller 25 in communication with the internal. That is, the outdoor unit 2 includes an outdoor unit controller 25, and the suction superheat acquisition device, the pressure sensor 23, and the respective indoor unit controllers 13 are connected to the outdoor unit controller 25; the external machine controller 25 receives the suction superheat degree obtained by the suction superheat degree obtaining device and the low pressure measured by the pressure sensor 23, and transmits the suction superheat degree and the low pressure received by the external machine controller to the internal machine controller 13.
In a specific embodiment, referring to fig. 4, 5 and 6, the indoor unit controller 13 is further configured with an operation time limit value, and configured to count up the duration of the refrigeration cycle temperature control operation of the indoor unit 1 and determine whether the duration of the refrigeration cycle temperature control operation reaches the operation time limit value; if so, a determination is made as to whether or not the internal motor expansion valve 12 is in the limit small opening state.
That is, when the temperature control operation integrated time of the multi-split refrigeration cycle reaches the operation time limit value or more, it is determined whether or not there is a control error in the opening degree of the internal motor expansion valve 12, and the control error affects the refrigeration effect. The refrigeration cycle temperature control operation accumulation time is the mode operation duration of the refrigeration cycle such as the refrigeration mode or the dehumidification mode, and is cleared when the operation mode is switched from the refrigeration cycle temperature control mode to other non-refrigeration cycle modes.
That is, the cooling mode temperature control operation time and the dehumidifying mode temperature control operation time are accumulated, and when the operation mode is switched from the cooling mode or the dehumidifying mode to other modes such as the heating mode and the air supply mode, the accumulated cooling cycle temperature control operation duration is cleared.
That is, the operation time in the temperature control mode is not accumulated in the cooling mode and in the dehumidifying mode; that is, in the cooling mode or the dehumidification mode, there is no temperature control operation, that is, there is no control of the internal electronic expansion valve 12, and there is no error in the internal electronic expansion valve 12.
The multi-split air conditioner of the embodiment prescribes judgment of the accumulated time length of the temperature control operation of the refrigeration cycle, reduces invalid judgment, prolongs the judgment period, reduces the judgment frequency, reduces occupied software and hardware resources, and improves the control efficiency.
In a specific embodiment, referring to fig. 5 and 6, the determination of the opening state of the internal motor expansion valve 12 is performed by determining whether the determination condition I is satisfied S2. The judging and judging condition I specifically comprises the following steps:
s21, judging whether the temperature control duration of the refrigeration cycle reaches the operation time limit or not; if so, a judgment of S22 is performed,
s22, judging whether the opening degree of the internal motor expansion valve 12 does not exceed a first opening degree limit value, and if so, executing the judgment of S23;
s23, judging whether the low pressure does not exceed a first low pressure limit value; if not, executing the judgment of S22; if yes, executing the judgment of S24;
s24, judging whether the difference between the inlet temperature and the suction superheat exceeds a first temperature limit value for a first duration or whether the difference between the elbow temperature and the suction superheat exceeds the first temperature limit value for the first duration; if yes, S3, opening degree increasing control is carried out; if not, executing the judgment of S25;
s25, judging whether the difference between the indoor temperature and the second temperature limit value does not exceed the inlet temperature for a first duration or whether the difference between the indoor temperature and the second temperature limit value does not exceed the elbow temperature for the first duration; if yes, executing S3 opening degree increasing control; if not, the judgment of S22 is performed.
In a specific embodiment, referring to fig. 4, 5, and 6, the indoor unit controller 13 is configured to end the opening degree increase control when the indoor unit 1 ends the refrigeration cycle. That is, when the indoor unit 1 determines that the indoor unit electronic expansion valve 12 is in the limit small opening state S2 and performs the opening increase control S3, if the indoor unit 1 switches the refrigeration cycle to another cycle S4, for example, when the cooling mode or the dehumidification mode is switched to the heating mode or the air blowing mode, S5 is performed to terminate the opening increase control. At this time, the accumulated refrigeration cycle temperature control mode duration is also cleared S6.
In some specific embodiments, referring to fig. 5, 6, 7, 8, 9, 10, and 11, the internal machine controller 13 is configured with an increased opening, a minimum opening, a delay time, a second opening limit, and a third temperature limit; the initial value of the minimum opening is set to 0; the second opening limit is greater than the first opening limit.
The opening degree increase control S3 includes the steps of:
s31, judging whether the minimum opening is 0 value; when the minimum opening is judged to be 0 value, S32 is executed;
s32, controlling the internal motor expansion valve 12 to be closed to 0 opening; s33 is performed in a stable delay time after the internal electronic expansion valve 12 is closed;
s33, acquiring an inlet temperature and an elbow temperature, and storing the acquired inlet temperature and elbow temperature;
S34, increasing the opening of the internal electronic expansion valve 12 at least once by the step number of increasing the opening; and executing S35 after increasing the number of steps of increasing the opening at a time;
s35, judging whether the opening degree of the internal motor expansion valve 12 exceeds a second opening degree limit value;
if yes, that is, if the opening degree of the internal electronic expansion valve 12 reaches the second opening degree limit value or more, the opening degree control of the internal electronic expansion valve 12 is performed S7 to return to the superheat degree control;
if not, that is, if the opening degree of the internal motor expansion valve 12 does not reach the second opening degree limit value, the judgment of the judgment condition II is performed S37 after the delay time; in particular to a special-shaped ceramic tile,
s37, judging whether the difference between the elbow temperature before increasing the opening degree and the elbow temperature after increasing the opening degree exceeds a third temperature limit value or whether the difference between the inlet temperature before increasing the opening degree and the inlet temperature after increasing the opening degree exceeds the third temperature limit value; and if yes, determining that the internal electronic expansion valve 12 is opened, and executing the judgment of the S38 minimum opening storage judgment condition III, the S1 minimum opening storage control and the S7 return superheat degree control; if not, the electronic expansion valve 12 is controlled to increase the opening degree by continuing to execute S34 control on the opening degree of the electronic expansion valve 12.
That is, when the opening degree of the internal motor expansion valve 12 does not reach the second opening degree limit value, starting to count time after increasing the opening degree from the opening degree of the internal motor expansion valve 12, and when the count time reaches the delay time, acquiring the inlet temperature and the elbow temperature, wherein the inlet temperature and the elbow temperature are the inlet temperature and the elbow temperature after increasing the opening degree; the inlet temperature and the elbow temperature are more stable after the delay time, the opening state of the electronic expansion valve of the indoor unit 1 after the opening is increased can be reflected, the accuracy is improved, and the judgment accuracy is further improved.
When a control error exists in the internal machine electronic expansion valve 12 and the control error affects the refrigerating effect, if the minimum opening has no stored non-zero value, the internal machine electronic expansion valve 12 is controlled to be closed to 0 opening for resetting, then the internal machine electronic expansion valve is gradually opened, whether the internal machine electronic expansion valve is opened to a normal state is judged by an inlet temperature difference or an elbow temperature difference between the internal machine electronic expansion valve and the opening before the opening is increased, the refrigerating effect is recovered, and the reliability and the accuracy for solving the problem that the control error of the internal machine electronic expansion valve 12 affects the refrigerating effect are improved.
In some specific embodiments, referring to fig. 7, the opening degree increase control S3 is specifically performed in the following steps:
S32, when the minimum opening is judged to be 0, the internal motor expansion valve 12 is closed;
s33, acquiring an inlet temperature and an elbow temperature for storage after delay time after the internal machine electronic expansion valve 12 is closed;
s34, controlling the opening degree of the internal motor expansion valve 12 to be increased to increase the opening degree;
s35, judging whether the opening degree of the internal motor expansion valve 12 exceeds a second opening degree limit value;
s36, after increasing the opening, obtaining and storing the inlet temperature and the elbow temperature after delay time;
s37 determines whether or not the determination condition II is satisfied.
In some specific embodiments, referring to fig. 9, the specific steps of determining condition II at S37 are as follows,
s371, judging whether the difference between the elbow temperature before increasing the opening and the elbow temperature after increasing the opening exceeds a third temperature limit value, and if so, performing minimum opening storage control; if not, then the determination of S372 is performed;
s372, judging whether the difference between the inlet temperature before increasing the opening degree and the inlet temperature after increasing the opening degree exceeds a third temperature limit value; if yes, determining that the internal motor expansion valve 12 is opened, and performing minimum opening storage control and return superheat control S7; if not, the opening degree increase control of the internal motor expansion valve 12 is continued.
In some specific embodiments, referring to fig. 5, 6, 7, 8, 9, 10, and 11, the minimum opening degree storage control includes:
s381, judging whether the low pressure is lower than a first low pressure limit value;
if yes, storing the minimum opening; and executing S11 to store the first opening limit value as the minimum opening and restore to the superheat degree control S7 when the opening of the current internal-machine electronic expansion valve 12 exceeds the control small opening limit value in the judgment S382; executing S12 to store the opening of the current internal electronic expansion valve 12 as the minimum opening and restore to superheat control S7 when the opening of the current internal electronic expansion valve 12 is judged not to exceed the control small opening limit value S382;
if not, the process returns to the superheat control S7.
The minimum opening in the indoor unit controller 13 of the multi-split air conditioner of the embodiment is stored only once, the non-zero stored value does not exceed the control small opening limit value, the minimum opening value is determined according to the actual running condition, the refrigeration is not stopped when the control error of the indoor unit expansion valve 12 after the minimum opening is stored is eliminated, the refrigeration effect of the indoor unit 1 is ensured, and the elimination efficiency of the error is improved.
In some specific embodiments, referring to fig. 5, 6, 7, 8, 9, 10, and 11, the increasing opening degree control S3 further includes:
S31, judging whether the minimum opening is 0 value; when the minimum opening is a non-zero value, S320 is performed;
s320, controlling the internal motor expansion valve 12 to be opened to a minimum opening degree;
s33, acquiring the inlet temperature and the elbow temperature after the internal electronic expansion valve 12 is closed and stabilizing the delay time, and storing the acquired inlet temperature and elbow temperature;
s34, increasing the opening of the internal electronic expansion valve 12 at least once by the step number of increasing the opening; and after increasing the number of steps of increasing the opening degree once, S35 is executed to determine whether the opening degree of the internal electronic expansion valve 12 exceeds the second opening degree limit value;
if yes, that is, if the opening degree of the internal electronic expansion valve 12 reaches the second opening degree limit value or more, the opening degree control of the internal electronic expansion valve 12 is restored to the superheat degree control S7;
if not, that is, the opening degree of the internal motor expansion valve 12 does not reach the second opening degree limit value, the determination is performed after the delay time whether the condition II is satisfied;
specifically, whether the difference between the elbow temperature before increasing the opening degree and the elbow temperature after increasing the opening degree exceeds a third temperature limit value or whether the difference between the inlet temperature before increasing the opening degree and the inlet temperature after increasing the opening degree exceeds the third temperature limit value is determined; and if yes, it is determined that the internal motor expansion valve 12 is opened, the operation returns to the superheat control S7, and if no, the internal motor expansion valve 12 is closed, and the determination and control S39 are performed.
The multi-split air conditioner of the embodiment improves the efficiency of eliminating the control error of the internal machine electronic expansion valve 12 by configuring the control method for increasing the opening of the internal machine electronic expansion valve 12 when the non-zero minimum opening is satisfied, recovers the refrigerating effect of the indoor machine 1 as soon as possible, and improves the user experience.
In some specific embodiments, referring to fig. 8, the opening degree increase control is specifically performed in the following steps:
s320, when the minimum opening is judged to be a value other than 0, resetting the internal machine electronic expansion valve 12 to the minimum opening;
s33, acquiring an inlet temperature and an elbow temperature for storage after the internal machine electronic expansion valve 12 is reset to the minimum opening and the delay time is passed;
s34, controlling the opening degree of the internal motor expansion valve 12 to be increased to increase the opening degree;
s35, judging whether the opening degree of the internal motor expansion valve 12 exceeds a second opening degree limit value;
s36, after increasing the opening, obtaining and storing the inlet temperature and the elbow temperature after delay time;
s37 determines whether or not the determination condition II is satisfied.
In some specific embodiments, referring to fig. 5 and 11, the determining of the closing confirmation of the electronic expansion valve 12 in S39, i.e., the control determining condition IV, includes:
s391, judging whether the difference between the indoor temperature and the second temperature limit exceeds the inlet temperature or not, and judging whether the difference between the indoor temperature and the second temperature limit exceeds the elbow temperature or not in S392;
If so, the internal motor expansion valve 12 returns to the superheat control S7; if not, the internal electronic expansion valve 12 is controlled to execute the next S34 increase in the increase opening degree.
When the increase opening control is completed, the operation time limit value is cleared S6.
When the multi-split air conditioner of the embodiment determines that the electronic expansion valve 12 of the indoor unit is in the closed state through the determination of the inlet temperature variation and the elbow temperature variation, the opening state of the electronic expansion valve 12 of the indoor unit is additionally determined through the difference value between the indoor temperature and the inlet temperature and the difference value between the indoor temperature and the elbow temperature, so that the opening state of the electronic expansion valve 12 of the indoor unit is more accurately determined, the accuracy and the reliability of the state determination of the electronic expansion valve 12 of the indoor unit are improved, the refrigerating effect of the indoor unit 1 is ensured, and the use experience of a user is improved.
In some specific embodiments, referring to fig. 5 and 11, the determination of the closing confirmation of the electronic expansion valve 12 and the control or determining condition IV in S39 is performed according to the following steps:
s391, judging whether the difference between the indoor temperature and the second temperature limit exceeds the inlet temperature, if so, executing S392; if not, returning to the control of increasing the opening degree;
s392, judging whether the difference between the indoor temperature and the second temperature limit exceeds the elbow temperature;
If so, the internal motor expansion valve 12 returns to the superheat control S7; if not, the internal electronic expansion valve 12 is controlled to execute the next round S34 to increase the opening degree.
In a specific embodiment, referring to fig. 7 and 8, when the electronic expansion valve 12 of the indoor unit is reset to the opening value of 0 and to the minimum opening value of non-zero, a delay time is required to make the indoor unit 1 stable, in particular to make the inlet temperature and the elbow temperature stable; and obtaining the inlet temperature and the elbow temperature.
After the opening degree increasing control is performed on the internal machine electronic expansion valve 12, the system, the inlet temperature and the elbow temperature after the opening degree increasing of the internal machine electronic expansion valve 12 is performed are stabilized through time delay, and the inlet temperature and the elbow temperature are obtained.
The multi-split air conditioner of the embodiment acquires the inlet temperature and the elbow temperature after the delay time after resetting and increasing the opening, improves the accuracy of the inlet temperature and the elbow temperature, and further improves the accuracy and the reliability of the control of the opening of the internal machine electronic expansion valve 12.
In some specific embodiments, the internal controller 13 is configured with a second pressure limit that is less than the first pressure limit; the internal machine controller 13 is configured to determine whether the low pressure is lower than a second pressure limit value when the internal machine electronic expansion valve 12 is in a limit small opening state; and when the low pressure is lower than the second pressure limit value, the opening degree of the electronic expansion valve 12 is controlled to be increased to the second opening limit value at one time, and the superheat degree control is restored.
The multi-split air conditioner of the embodiment confirms that the opening error of the electronic expansion valve of the indoor unit 1 has reached the extent that the operation of the air conditioning system is affected by judging whether the low pressure is lower than the second pressure limit value, so that the control of the electronic expansion valve 12 of the indoor unit is increased to the control of the large opening limit value once, the low pressure of the system is recovered as soon as possible, the normal refrigeration of the whole system of the multi-split air conditioner is ensured, and the stability, reliability and refrigeration effect of the operation of the multi-split air conditioner are improved.
In a specific embodiment, the superheat obtaining device includes an intake air temperature sensor 24 and a second pressure sensor, which are respectively disposed at the air intake of the compressor 21, connected to the inner machine controller 13 or the outer machine controller 25, and used for detecting the intake air temperature and the intake air pressure and transmitting the detected intake air temperature and the detected intake air pressure to the inner machine controller 13 or the outer machine controller 25; the internal unit controller 13 or the external unit controller 25 calculates the suction superheat degree from the suction temperature and the suction pressure.
The suction temperature and suction pressure are transmitted to the external machine controller 25, and the external machine controller 25 calculates the suction superheat degree according to the saturation temperature corresponding to the suction temperature and suction pressure reduced by the suction superheat degree and transmits the suction superheat degree to the internal machine controller 13.
In a specific embodiment, the indoor unit 1 further includes an outlet temperature sensor, which is disposed at the outlet 113 of the indoor heat exchanger 11, connected to the indoor unit controller 13, and used for detecting the outlet temperature and transmitting to the indoor unit controller 13; the internal machine controller 13 is further provided with a superheat setting value, and PI control is performed on the internal machine expansion valve 12 based on the difference between the outlet temperature and the inlet temperature and the difference between the superheat setting value.
Specifically, the deviation E (n) = [ Tout (n) -Tin (n) ] -SH;
the maximum value of the deviation E (n) is sh×2; when n in parentheses is 0, E (n) is 0.
SH is a superheat degree set value, namely a target superheat degree, and different values are set according to the refrigerant type and different operation stages of the multi-split air conditioner;
tout (n): the outlet temperature of the indoor heat exchanger 11 sampled n times, i.e., the outlet temperature detected by the outlet temperature sensor;
tin (n): the inlet temperature of the indoor heat exchanger 11 sampled n times, that is, the lower temperature of the inlet temperature and the elbow temperature detected by the inlet temperature sensor 14 and the elbow sensor.
The opening degree variation value Δp of the superheat-controlled internal-motor expansion valve 12 is calculated by the following equation:
ΔP=Pfb（n）max/100×{Kp×[ΔE（n）+ΔT/Ti×E（n）]}+G×[ANS（n）-ANS（n-1）]；
ΔE（n）=E（n）-E（n-1）；
in the method, in the process of the invention,
e (n-1) for the first time at the start of the superheat control is 0.
Pfb (n) max is the maximum opening of the internal electronic expansion valve 12;
kp is a proportional value, and is set according to the opening section where the internal motor expansion valve 12 is positioned and the model, and increases along with the increase of the opening section, so that overshoot is prevented;
delta T is the sampling time;
ti is the integration time;
DeltaT/Ti×E (n) is a variable of time integration;
g is the distinction of machine types, and machine types of different capacity sections are assigned differently;
ANS (n) is a frequency feedback value of the compressor 21, and a trend of the frequency of the compressor 21 when the frequency is increased or decreased is fed back to the internal expansion valve, so that the opening degree of the internal electronic expansion valve 12 is controlled in consideration of the amount of change in the frequency of the compressor 21, thereby preventing excessive control.
The multi-split air conditioner of the embodiment enables the superheat degree control of the electronic expansion valve 12 of the inner machine to be more accurate, and further the indoor temperature is finely controlled.
In the description of the above embodiments, particular features, structures, materials, or characteristics may be combined in any suitable manner in any one or more embodiments or examples.
The foregoing is merely illustrative of the present invention, and the present invention is not limited thereto, and any changes or substitutions easily contemplated by those skilled in the art within the scope of the present invention should be included in the scope of the present invention. Therefore, the protection scope of the invention is subject to the protection scope of the claims.
Claims (10)
1. A multi-split air conditioner is characterized by comprising an outdoor unit and a plurality of indoor units; the indoor unit comprises an indoor heat exchanger and an indoor machine electronic expansion valve; the indoor heat exchanger is connected with the outdoor unit through the internal machine electronic expansion valve; the indoor heat exchanger comprises an inlet, an outlet and a plurality of elbows;
The indoor unit further comprises an indoor unit controller, an inlet temperature sensor, an elbow temperature sensor and an indoor temperature sensor which are respectively connected with the indoor unit controller; the inlet temperature sensor and the elbow temperature sensor are respectively arranged at the inlet and one of the elbows and used for detecting the inlet temperature and the elbow temperature and transmitting the inlet temperature and the elbow temperature to the internal machine controller; the indoor temperature sensor is used for detecting indoor temperature and transmitting the indoor temperature to the indoor unit controller;
the internal machine controller is configured to judge whether the internal machine electronic expansion valve is in a limit small opening state according to the inlet temperature, the elbow temperature and the indoor temperature; when the internal electronic expansion valve is in a limit small opening state, controlling the internal electronic expansion valve to increase the opening; and when the internal motor expansion valve is not in the limit small opening state, the superheat control is kept to be executed.
2. The multi-split air conditioner according to claim 1, further comprising an intake superheat obtaining device and a pressure sensor, which are arranged on the outdoor unit, respectively connected with the indoor unit controller, and are used for obtaining the intake superheat and the low pressure of the outdoor unit and transmitting the obtained intake superheat and the low pressure to the indoor unit controller;
The internal machine controller is configured with a first temperature limit value, a second temperature limit value, a first opening limit value, a first low-pressure limit value, and a first time period, and is configured to determine whether an opening degree of the internal machine electronic expansion valve is lower than the first opening limit value, whether the low-pressure is lower than the first low-pressure limit value, and whether a difference between the inlet temperature and the suction superheat exceeds the first temperature limit value for the first time period or a difference between the elbow temperature and the suction superheat exceeds the first temperature limit value for the first time period or a difference between the indoor temperature and the second temperature limit value does not exceed the inlet temperature for the first time period or a difference between the indoor temperature and the second temperature limit value does not exceed the elbow temperature for the first time period;
when the conditions are judged to be yes, determining that the internal electronic expansion valve is in the limit small opening state; otherwise, the state is not the limit small opening state.
3. The multi-split air conditioner according to claim 2, wherein the internal machine controller is further configured with an operation time limit value and is configured to accumulate a refrigeration cycle temperature control mode duration, determine whether the refrigeration cycle temperature control mode duration reaches the operation time limit value or more, and if so, determine whether the internal machine electronic expansion valve is in the limit small opening state.
4. The multi-split air conditioner of claim 3, wherein the indoor unit controller is configured to end the increased opening degree control if the indoor unit ends a refrigeration cycle when executing the increased opening degree control;
and when the indoor unit finishes the refrigeration cycle or is switched to other operation modes, the duration of the refrigeration cycle temperature control mode is cleared.
5. The multi-split air conditioner according to any one of claims 1 to 4, wherein the indoor unit controller is configured with an increased opening degree, a minimum opening degree, a second opening degree limit value, and a third temperature limit value; the initial value of the minimum opening is 0; the second opening limit is greater than the first opening limit; the opening degree increase control includes:
judging whether the minimum opening is 0; when the valve is 0, the internal electronic expansion valve is controlled to be closed;
after the internal electronic expansion valve is closed, the opening of the internal electronic expansion valve is increased at least once; judging whether the opening of the internal electronic expansion valve exceeds the second opening limit value after increasing the opening every time; if yes, controlling the internal electronic expansion valve to recover the superheat control; if not, judging whether the difference between the elbow temperature before increasing the opening degree and the elbow temperature after increasing the opening degree exceeds the third temperature limit value or whether the difference between the inlet temperature before increasing the opening degree and the inlet temperature after increasing the opening degree exceeds the third temperature limit value, and if so, judging that the internal electronic expansion valve is opened, performing minimum opening degree storage control and recovering the superheat degree control, and if not, controlling the internal electronic expansion valve to continuously increase the opening degree.
6. The multi-split air conditioner of claim 5, wherein the minimum opening storage control includes:
judging whether the low pressure is lower than the first low pressure limit value;
if yes, judging whether the current opening of the internal electronic expansion valve exceeds the first opening limit value, and if yes, storing the first opening limit value to the minimum opening and recovering the superheat degree control, and if not, storing the current opening of the internal electronic expansion valve to the minimum opening and recovering the superheat degree control;
if not, directly recovering the superheat control.
7. The multi-split air conditioner of claim 6, wherein the increasing opening degree control further comprises:
judging whether the minimum opening is 0; when the opening degree is not 0, controlling the internal electronic expansion valve to be opened to the minimum opening degree;
after the internal electronic expansion valve is opened to the minimum opening, the opening of the internal electronic expansion valve is increased at least once; judging whether the opening of the internal electronic expansion valve exceeds the second opening limit value after increasing the opening every time; if yes, controlling the internal electronic expansion valve to recover the superheat control; if not, judging whether the difference between the elbow temperature before increasing the opening degree and the elbow temperature after increasing the opening degree exceeds the third temperature limit value or whether the difference between the inlet temperature before increasing the opening degree and the inlet temperature after increasing the opening degree exceeds the third temperature limit value, and if yes, judging that the internal motor expansion valve is opened, recovering the superheat degree control, and if not, performing closing confirmation judgment and control of the internal motor expansion valve.
8. The multi-split air conditioner of claim 7, wherein the internal motor expansion valve closing confirmation judging and controlling includes:
judging whether the difference between the indoor temperature and the second temperature limit exceeds the inlet temperature and whether the difference between the indoor temperature and the second temperature limit exceeds the elbow temperature;
and if so, the internal electronic expansion valve resumes the superheat control, and if not, the opening degree of the internal electronic expansion valve is controlled to be continuously increased by the increased opening degree.
9. The multi-split air conditioner of claim 8, wherein the indoor unit controller is configured with a second pressure limit that is less than the first pressure limit; the internal machine controller is configured to determine whether the low pressure is lower than the second pressure limit value when the internal machine electronic expansion valve is in the limit small opening state; and when the low pressure is lower than the second pressure limit value, controlling the opening of the internal electronic expansion valve to be increased to the second opening limit value, and recovering the superheat control.
10. The multi-split air conditioner of claim 1, further comprising an outlet temperature sensor disposed at the outlet, connected to the internal controller, for detecting the outlet temperature and transmitting to the internal controller; the inner machine controller is also configured with a superheat setting value; and the superheat degree control is to perform suction superheat degree PI control through the difference between the outlet temperature and the inlet temperature and the superheat degree set value, and is used for controlling the opening of the internal electronic expansion valve.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202310416378.9A CN116412464A (en) | 2023-04-18 | 2023-04-18 | Multi-split air conditioner |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202310416378.9A CN116412464A (en) | 2023-04-18 | 2023-04-18 | Multi-split air conditioner |
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