CN113137715A - Control method for compressor frequency of multi-split air conditioner and multi-split air conditioner - Google Patents
Control method for compressor frequency of multi-split air conditioner and multi-split air conditioner Download PDFInfo
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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
- F24F11/30—Control or safety arrangements for purposes related to the operation of the system, e.g. for safety or monitoring
- F24F11/32—Responding to malfunctions or emergencies
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- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
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- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
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- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
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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
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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
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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
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Abstract
The invention relates to a control method for the compressor frequency of a multi-split air conditioner and the multi-split air conditioner using the control method. The control method comprises the following steps: detecting a real-time starting load KF of the multi-split air conditioner; based on real-time start-up burdenThe charge KF at least determines a first dynamic exhaust temperature threshold and a second dynamic exhaust temperature threshold smaller than the first dynamic exhaust temperature threshold; measuring real-time discharge temperature T of compressord(ii) a Will exhaust the temperature T in real timedComparing with first and second dynamic exhaust temperature thresholds, respectively; when real-time exhaust temperature TdWhen the temperature is greater than the first dynamic exhaust temperature threshold value, the compressor is stopped for a first preset time period; and when the real-time exhaust temperature T isdAnd when the temperature is less than or equal to the first dynamic exhaust temperature threshold and is greater than the second dynamic exhaust temperature threshold, reducing the frequency of the compressor, wherein the change directions of the first dynamic exhaust temperature threshold and the second dynamic exhaust temperature threshold are consistent with the change direction of the real-time startup load KF. The method can prevent the exhaust temperature frequency limiting program from failing under low load.
Description
Technical Field
The invention relates to an air conditioning system, in particular to a control method of compressor frequency of a multi-split air conditioner and the multi-split air conditioner.
Background
A multi-split air conditioner generally refers to an air conditioner having N (N is an integer greater than 1) indoor units. When the air conditioner is used, a user can randomly start one, two, three or N indoor units according to actual needs. For example, chinese patent CN106352611B discloses such a multi-split air conditioner. The multi-split air conditioner comprises an outdoor unit and at least two indoor heat exchangers (equivalent to two indoor units) which can form a refrigerating loop with the outdoor unit. The outdoor unit includes a compressor, a four-way valve, an outdoor heat exchanger, and an electronic expansion valve arranged in the same refrigeration circuit. The outdoor unit may also include more than one compressor to meet greater load demands.
When the air conditioner exhaust temperature is too high and reaches a certain temperature, the compressor of the air conditioner is subjected to protective shutdown. In order to avoid protective shutdown, in order to cooperate with the protection of overhigh exhaust temperature of the compressor, the frequency of the compressor needs to be controlled according to the exhaust temperature limit value, so that the exhaust temperature of the compressor is effectively controlled, and the normal operation of the air conditioning system is ensured. In the prior art, the exhaust temperature limit value (also referred to as "exhaust temperature threshold value") is a temperature value preset in the air conditioning system. These preset temperature values remain unchanged regardless of the actual load of the air conditioning system. Turning on different numbers of indoor units means that the power-on load is also different. With the change of the starting load, the relation between the exhaust temperature and the refrigerant pressure of the air conditioning system is changed correspondingly. In this case, the same exhaust temperature frequency limiting value may cause the exhaust temperature frequency limiting procedure to fail under low load, and thus the exhaust temperature frequency limiting function cannot be performed.
Accordingly, there is a need in the art for a new solution to the above problems.
Disclosure of Invention
In order to solve the above problems in the prior art, that is, to solve the technical problem that the frequency limiting procedure of the exhaust temperature under low load is invalid due to the existing frequency control method of the compressor, the invention provides a frequency control method of the compressor of the multi-split air conditioner. The multi-split air conditioner includes a variable frequency compressor, and the control method includes:
detecting a real-time starting load KF of the multi-split air conditioner;
at least determining a first dynamic exhaust temperature threshold and a second dynamic exhaust temperature threshold smaller than the first dynamic exhaust temperature threshold based on the real-time startup load KF;
measuring a real-time discharge temperature T of the compressord；
Setting the real-time exhaust temperature TdComparing with the first dynamic exhaust temperature threshold and the second dynamic exhaust temperature threshold, respectively;
when the real-time exhaust temperature TdGreater than the first dynamic discharge temperature threshold, the compressor is shutdown for a first predetermined period of time; and whenThe real-time exhaust temperature TdReducing the frequency of the compressor when the first dynamic discharge temperature threshold is less than or equal to the first dynamic discharge temperature threshold and greater than the second dynamic discharge temperature threshold,
and the change direction of the first dynamic exhaust temperature threshold and the second dynamic exhaust temperature threshold is consistent with the change direction of the real-time startup load KF.
It can be understood by those skilled in the art that, in the method for controlling the frequency of the compressor of the one-drive-many air conditioner of the present invention, the first dynamic discharge temperature threshold for controlling the shutdown of the compressor and the second dynamic discharge temperature threshold for controlling the down-conversion of the compressor are determined based on the real-time startup load and vary with the variation of the real-time startup load, and thus may be regarded as "dynamic". Further, the change direction of the first dynamic exhaust temperature threshold and the second dynamic exhaust temperature threshold is consistent with the change direction of the real-time startup load. That is, when the real-time startup load increases, both the first dynamic exhaust temperature threshold and the second dynamic exhaust temperature threshold increase accordingly; when the real-time startup load decreases, the first dynamic exhaust temperature threshold and the second dynamic exhaust temperature threshold are both decreased accordingly. Therefore, the control method can avoid the problem that the exhaust temperature frequency limiting program of the multi-split air conditioner fails under low load.
In a preferred embodiment of the method for controlling the frequency of the compressor of the multi-split air conditioner, the method further includes:
determining a third dynamic exhaust temperature threshold based on the real-time startup load KF, wherein the third dynamic exhaust temperature threshold is smaller than the second dynamic exhaust temperature threshold;
setting the real-time exhaust temperature TdComparing to the third dynamic exhaust temperature threshold;
when the real-time exhaust temperature TdGreater than the third dynamic discharge temperature threshold and less than or equal to the second dynamic discharge temperature threshold, maintaining the frequency of the compressor constant,
wherein the change direction of the third dynamic exhaust temperature threshold and the change direction of the real-time startup load KFAnd (5) the consistency is achieved. The third dynamic exhaust temperature threshold determined based on the real-time startup load KF is used to determine under what conditions the compressor frequency can be kept constant. Specifically, at real-time exhaust temperature TdThe compressor frequency may remain unchanged for conditions greater than the third dynamic discharge temperature threshold and less than or equal to the second dynamic discharge temperature threshold.
In a preferred embodiment of the method for controlling the frequency of the compressor of the multi-split air conditioner, the method further includes:
determining a fourth dynamic exhaust temperature threshold based on the real-time startup load KF, wherein the fourth dynamic exhaust temperature threshold is smaller than the third dynamic exhaust temperature threshold;
setting the real-time exhaust temperature TdComparing to the fourth dynamic exhaust temperature threshold;
when the real-time exhaust temperature TdWhen the temperature is greater than the fourth dynamic exhaust temperature threshold and less than or equal to the third dynamic exhaust temperature threshold, the multi-split air conditioner enters a compressor frequency automatic control mode; and when the real-time exhaust temperature T isdIncreasing the frequency of the compressor when the dynamic discharge temperature is less than or equal to a fourth dynamic discharge temperature threshold,
and the change direction of the fourth dynamic exhaust temperature threshold is consistent with the change direction of the real-time startup load KF. The fourth dynamic discharge temperature threshold determined based on the real-time startup load KF is used to determine under what conditions the compressor needs to be upscaled and under what conditions the compressor (and thus the multi-split air conditioner) can enter the normal control mode, i.e., the automatic control mode based on the indoor cooling/heating demand. Specifically, at real-time exhaust temperature TdUnder the condition that the temperature is greater than the fourth dynamic exhaust temperature threshold and less than or equal to the third dynamic exhaust temperature threshold, the current exhaust temperature is relatively suitable, so that the multi-split air conditioner can enter a compressor frequency automatic control mode according to indoor cooling/heating requirements. When real-time exhaust temperature TdAnd when the temperature is less than or equal to the fourth dynamic exhaust temperature threshold value, judging whether the frequency of the compressor needs to be increased or not according to the indoor cooling/heating requirement.
In a preferred embodiment of the method for controlling the frequency of the compressor of the multi-split air conditioner, the method further includes:
determining a second additional dynamic exhaust temperature threshold based on the real-time startup load KF, wherein the second additional dynamic exhaust temperature threshold is less than or equal to the first dynamic exhaust temperature threshold and greater than the second dynamic exhaust temperature threshold;
setting the real-time exhaust temperature TdComparing to the second additional dynamic exhaust temperature threshold;
when the real-time exhaust temperature TdWhen the temperature is greater than the second additional dynamic exhaust temperature threshold and less than or equal to the first dynamic exhaust temperature threshold, reducing the frequency of the compressor at a higher speed; and when the real-time exhaust temperature T isdGreater than the second dynamic discharge temperature threshold and less than or equal to the second additional dynamic discharge temperature threshold, reducing the frequency of the compressor at a slower speed,
and the change direction of the second additional dynamic exhaust temperature threshold is consistent with the change direction of the real-time startup load KF. A second additional dynamic exhaust temperature threshold determined based on the real-time startup load KF is used to control the compressor down-conversion speed. When real-time exhaust temperature TdAnd when the frequency of the compressor is greater than the second additional dynamic exhaust temperature threshold and less than or equal to the first dynamic exhaust temperature threshold, the frequency reduction speed of the compressor is relatively higher. When real-time exhaust temperature TdAnd when the frequency of the compressor is greater than the second dynamic exhaust temperature threshold and less than or equal to the second additional dynamic exhaust temperature threshold, the frequency reduction speed of the compressor is relatively slow. This allows for more accurate adjustment of the compressor downconversion process.
In the above preferred technical solution of the method for controlling the frequency of the compressor of the multi-split air conditioner, after the compressor is stopped for a first predetermined time period, the compressor is restarted and the real-time discharge temperature T is re-measureddAnd the current real-time exhaust temperature T is measureddComparing with the first dynamic exhaust temperature threshold if the real-time exhaust temperature TdGreater than the first dynamic discharge temperature threshold, the compressor is shutdown for a second predetermined period of timeThe second predetermined period of time is greater than the first predetermined period of time. The compressor is stopped and restarted after a first predetermined period of time. At this time, the real-time exhaust temperature T of the compressor needs to be measured againdAnd again the current real-time exhaust temperature TdAnd compared to a first dynamic exhaust temperature threshold. If the current real-time exhaust temperature TdThe frequency reduction speed of the compressor cannot achieve the effect of quickly reducing the exhaust temperature after the frequency reduction speed of the compressor is still larger than the first dynamic exhaust temperature threshold, which indicates that the frequency reduction speed needs to be increased to meet the requirement of stable operation of the system after the frequency reduction speed of the compressor reaches the second dynamic exhaust temperature threshold.
In a preferred embodiment of the method for controlling a frequency of a compressor of a multi-split air conditioner, after the compressor is stopped for a second predetermined period of time, the method further includes:
judging whether the restarting frequency of the compressor in a third preset time period is smaller than a preset frequency, wherein the preset frequency is not less than 3;
restarting the compressor and operating the compressor at a low frequency for a fourth predetermined period of time if the number of restarts is less than a predetermined number;
if the restart time is more than or equal to the preset time, sending a high-frequency exhaust fault alarm,
wherein the second predetermined period of time is greater than the first predetermined period of time and less than the third predetermined period of time. And after the compressor is stopped for the second time and a second preset time period elapses, judging whether the total starting times of the compressor are less than the preset times. If the total number of compressor restarts is less than the predetermined number, it is indicated that attempts may also be continued to reduce the real-time discharge temperature T of the compressor by stopping the compressord. If the total number of compressor restarts has reached a predetermined number, it indicates that a pure shutdown does not reduce the real-time discharge temperature T of the compressordA fault in the compressor or in the multi-split air conditioner that may cause high exhaust temperatures may be present, thus giving a high frequency exhaust fault alarm.
In a preferred embodiment of the method for controlling the frequency of the compressor of the multi-split air conditioner, after the frequency of the compressor is reduced, the fifth predetermined time is elapsedInterval of time, re-measuring said real-time exhaust temperature TdAnd the current real-time exhaust temperature T is measureddComparing with the second dynamic exhaust temperature threshold if the real-time exhaust temperature TdAnd if the second dynamic discharge temperature threshold is greater than the first dynamic discharge temperature threshold, repeating the step of reducing the frequency of the compressor. After a fifth preset time period after the frequency of the compressor is reduced, the real-time exhaust temperature T of the compressor is measured againdAnd the current real-time exhaust temperature T is measureddAnd a second dynamic exhaust temperature threshold. If the real-time exhaust temperature TdIf the temperature is still greater than the second dynamic exhaust temperature threshold and less than or equal to the first dynamic exhaust temperature threshold, it indicates that the previous frequency reduction process has not achieved the expected cooling effect, and therefore, the frequency of the compressor needs to be reduced again.
In a preferred embodiment of the method for controlling the frequency of the compressor of the multi-split air conditioner, after the frequency of the compressor is increased, the real-time exhaust temperature T is measured again after the sixth predetermined period of time elapsesdAnd the current real-time exhaust temperature T is measureddComparing with the fourth dynamic exhaust temperature threshold if the real-time exhaust temperature TdAnd repeating the step of increasing the frequency of the compressor if the fourth dynamic discharge temperature threshold is less than or equal to. After the compressor is up-converted, if the measured real-time exhaust temperature T isdStill below the fourth dynamic discharge temperature threshold, indicating that the compressor frequency may be further increased to increase the discharge temperature of the compressor.
In a preferred embodiment of the method for controlling the frequency of the compressor of the multi-split air conditioner, the first dynamic discharge temperature threshold, the second additional dynamic discharge temperature threshold, the second dynamic discharge temperature threshold, the third dynamic discharge temperature threshold, and the fourth dynamic discharge temperature threshold are respectively calculated based on the following formulas:
the first dynamic exhaust gas temperature threshold is equal to the first reference temperature +10KF (1),
the second dynamic exhaust gas temperature threshold is equal to the second reference temperature +10KF (2),
the third dynamic exhaust gas temperature threshold is the third reference temperature +10KF (3),
the fourth dynamic exhaust gas temperature threshold is the fourth reference temperature +10KF (4),
the second additional dynamic exhaust temperature threshold is a second additional reference temperature +10KF (5),
wherein KF is the real-time starting load of the multi-split air conditioner, and the unit is,
the first reference temperature > the second additional reference temperature > the second reference temperature > the third reference temperature > the fourth reference temperature, and are all constant. Through the corresponding formula, each dynamic exhaust temperature threshold value can be ensured to be related to the real-time startup load KF and keep consistent with the change direction of the real-time startup load KF.
In order to solve the above problems in the prior art, i.e. to solve the technical problem that the prior one-drive-many air conditioner causes the failure of the frequency limiting procedure of the exhaust temperature under low load when implementing high exhaust temperature protection on the compressor, the invention also provides the one-drive-many air conditioner, wherein the one-drive-many air conditioner comprises a variable-frequency compressor, and the one-drive-many air conditioner controls the frequency of the compressor by using the control method according to any one of the above. By using the control method of the compressor frequency, the air conditioner with one drive and multiple compressors can overcome the technical problem that the exhaust temperature frequency limiting program fails under low load.
Drawings
Preferred embodiments of the present invention are described below with reference to the accompanying drawings, in which:
FIG. 1 is a system diagram of an embodiment of a multi-split air conditioner of the present invention;
FIG. 2 is a flow chart illustrating a method for controlling a frequency of a compressor of the multi-split air conditioner according to the present invention;
fig. 3 is a flowchart of a control method of a compressor frequency of a multi-split air conditioner according to a first embodiment of the present invention;
fig. 4 is a flowchart of a control method of a compressor frequency of a multi-split air conditioner according to a second embodiment of the present invention;
FIG. 5 is a first portion of a flow chart of a third embodiment of a method for controlling a compressor frequency of a multi-split air conditioner in accordance with the present invention;
fig. 6 is a second part of a flowchart of a method for controlling a frequency of a compressor of a multi-split air conditioner according to a third embodiment of the present invention.
Reference numerals:
1. a multi-split air conditioner; 11. an outdoor unit; 111. a compressor; 112. a gas-liquid separator; 113. an outdoor heat exchanger; 114. an outdoor heat exchanger fan; 115. a dispenser; 116. a four-way valve; 117. a liquid stop valve; 118. a gas shutoff valve; 119. a gaseous refrigerant header; 120. a liquid refrigerant header; 121a, a first filter; 121b, a second filter; 121c, a third filter; 121d, a fourth filter; 122a, a first electronic expansion valve; 122b, a second electronic expansion valve; 122c, a third electronic expansion valve; 122d, a fourth electronic expansion valve; 123a, a first gas pipe connecting branch; 123b, a second air pipe connecting branch; 123c, a third air pipe connecting branch; 123d, a fourth air pipe connecting branch; 124a, a first liquid pipe connecting branch; 124b, a second liquid pipe connecting branch; 124c, a third liquid pipe connecting branch; 124d, a fourth liquid pipe connecting branch; 125. an exhaust gas temperature sensor; 126. an outdoor heat exchanger temperature sensor; 127. a defrost sensor; 21. an indoor unit A; 211. an indoor heat exchanger; 212. an indoor heat exchanger fan; 213. indoor heat exchanger temperature sensor.
Detailed Description
Preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only for explaining the technical principle of the present invention, and are not intended to limit the scope of the present invention.
The invention provides a control method for the frequency of a compressor of a multi-split air conditioner, which aims to solve the technical problem that the existing multi-split air conditioner fails in the exhaust temperature frequency limiting program under low load. The multi-split air conditioner 1 comprises a variable frequency compressor, and the control method comprises the following steps:
detecting a real-time startup load KF of the multi-split air conditioner (step S1);
determining at least a first dynamic exhaust temperature threshold and a second dynamic exhaust temperature threshold that is less than the first dynamic exhaust temperature threshold based on the real-time startup load KF (step S2);
measuring real-time discharge temperature T of compressord(step S3);
will exhaust the temperature T in real timedComparing with a first dynamic exhaust temperature threshold and a second dynamic exhaust temperature threshold, respectively (step S4);
when real-time exhaust temperature TdWhen the temperature is greater than the first dynamic exhaust temperature threshold value, the compressor is stopped for a first preset time period; and when the real-time exhaust temperature T isdWhen the temperature is less than or equal to the first dynamic exhaust temperature threshold and greater than the second dynamic exhaust temperature threshold, the frequency of the compressor is reduced (step S5),
and the change direction of the first dynamic exhaust temperature threshold and the second dynamic exhaust temperature threshold is consistent with the change direction of the real-time startup load KF.
Fig. 1 is a system diagram of an embodiment of a multi-split air conditioner of the present invention. As shown in fig. 1, the one-drive-multiple air conditioner 1 includes an outdoor unit 11 (which is generally disposed in an outdoor environment) and a plurality of parallel-connected indoor units 21 (which are generally disposed in a room or a room) that are interconnectable into a refrigeration circuit that allows a refrigerant to flow therein. In one or more embodiments, the one-drive-multiple air conditioner 1 has four indoor units connected in parallel: indoor unit a, indoor unit B, indoor unit C, and indoor unit D. Fig. 1 shows only the indoor unit a, i.e., the indoor unit 21, and the remaining three indoor units are omitted. According to actual needs, the configuration of the four indoor units may be the same or different. Alternatively, the one-to-many air conditioner 1 may have two indoor units, three indoor units, or more than four indoor units.
As shown in fig. 1, in one or more embodiments, the outdoor unit 11 mainly includes a compressor 111, a gas-liquid separator 112, an outdoor heat exchanger 113, an outdoor heat exchanger fan 114, a four-way valve 116, and an electronic expansion valve. Due to the four-way valve 116, the multi-split air conditioner 1 at least has the functions of cooling and heating. Alternatively, the outdoor unit 11 may not include the four-way valve 116, which means that the one-to-many air conditioner does not have a heating function. In one or more embodiments, the compressor 111 is an inverter compressor. Alternatively, the compressor 111 may include two or more compressors in parallel. These compressors may be all inverter compressors or may include some inverter compressors. The compressor 111 has a suction port and a discharge port (not shown). An exhaust port of the compressor 111 is connected to a compressor connection port on the four-way valve 116 through a refrigerant pipe (i.e., a pipe allowing a refrigerant to flow therein). An exhaust temperature sensor 125 for measuring the exhaust temperature of the compressor 111 is disposed on the refrigerant pipe near the exhaust port of the compressor 111. A suction port of the compressor 111 is connected to an outlet port of the gas-liquid separator 112 through a refrigerant pipe, and an inlet port of the gas-liquid separator 112 is connected to a gas-liquid separator connection port of the four-way valve 116 through a refrigerant pipe. The four-way valve 116 is further provided with an outdoor heat exchanger connection port and an indoor heat exchanger connection port. One end of the outdoor heat exchanger 113 is connected to an outdoor heat exchanger connection port of the four-way valve 116 through a refrigerant pipe. The outdoor heat exchanger 113 may be, but is not limited to, a finned coil heat exchanger and a plate heat exchanger, and is provided with an outdoor heat exchanger fan 114. The other end of the outdoor heat exchanger 113 is connected to the distributor 115. An outdoor heat exchanger temperature sensor 126 and a defrost sensor 127 are also provided on the outdoor heat exchanger 113, respectively.
As shown in fig. 1, an indoor heat exchanger connection port of the four-way valve 116 is connected to a gaseous refrigerant header 119 through a refrigerant pipe, and a gas shutoff valve 118 is provided at the refrigerant pipe. The gaseous refrigerant header 119 is provided with four gas pipe connection branches: a first gas pipe connection branch 123a configured to be connectable to the indoor unit a; a second gas pipe connection branch 123B configured to be connectable to the indoor unit B; a third gas pipe connection branch 123C configured to be connectable to the indoor unit C; and a fourth air pipe connection branch 123D configured to be connectable to the indoor unit D. As shown in fig. 1, the distributor 115 is connected to a liquid refrigerant header 120 through a refrigerant pipe, and a liquid shutoff valve 117 is provided on the refrigerant pipe. The liquid refrigerant header 120 is provided with four liquid pipe connecting branches: a first liquid pipe connection branch 124a configured to be connectable to the indoor unit a; a second liquid pipe connection branch 124B configured to be connectable to the indoor unit B; a third pipe connection branch 124C configured to be connectable to the indoor unit C; and a fourth liquid pipe connection branch 124D configured to be connectable to the indoor unit D. A first filter 121a and a first electronic expansion valve 122a are disposed on the first liquid-pipe connection branch 124a, wherein the first filter 121a is located between the indoor unit a and the first electronic expansion valve 122 a. A second filter 121B and a second electronic expansion valve 122B are disposed on the second liquid pipe connection branch 124B, wherein the second filter 121B is located between the indoor unit B and the second electronic expansion valve 122B. A third filter 121C and a third electronic expansion valve 122C are disposed on the third liquid-pipe connection branch 124C, wherein the third filter 121C is located between the indoor unit C and the third electronic expansion valve 122C. A fourth filter 121D and a fourth electronic expansion valve 122D are disposed on the fourth liquid-pipe connection branch 124D, wherein the fourth filter 121D is located between the indoor unit D and the fourth electronic expansion valve 122D.
As shown in fig. 1, the indoor unit a21 includes an indoor heat exchanger 211, an indoor heat exchanger fan 212, and an indoor heat exchanger temperature sensor 213 that measures the temperature of the indoor heat exchanger 211. The indoor heat exchanger 211 includes, but is not limited to, a fin-and-tube type heat exchanger. Both ends of the indoor heat exchanger 211 may be connected to the first gas pipe connection branch 123a and the first liquid pipe connection branch 124a, respectively.
By means of the four-way valve 116, the multi-split air conditioner 1 can perform cooling and heating cycles. In the refrigeration cycle, the outdoor heat exchanger 113 functions as a condenser, and the indoor heat exchanger 211 functions as an evaporator. When the multi-split air conditioner receives a cooling command, the compressor 111 starts to be started, and the refrigerant (e.g., R410a) is compressed by the compressor 111 and then enters the outdoor heat exchanger 113 (which serves as a condenser) through the interconnected ports of the four-way valve 116 in the form of high-temperature and high-pressure gas. In the outdoor heat exchanger 113, the high-temperature and high-pressure gas refrigerant is condensed into a high-temperature and high-pressure liquid refrigerant by transferring heat to an air flow caused by the outdoor heat exchanger fan 114. The high-temperature and high-pressure liquid refrigerant flows through the distributor 115 and the liquid shutoff valve 117 in this order and enters the liquid refrigerant header 120. Then, the high-temperature and high-pressure liquid refrigerant is distributed to one or more of the first, second, third, and fourth liquid- pipe connection branches 124a, 124b, 124c, and 124d connected to the started indoor units, and is expanded into a low-temperature and low-pressure liquid refrigerant by the corresponding electronic expansion valves of the one or more liquid-pipe connection branches. The low-temperature and low-pressure liquid refrigerant then flows into the indoor heat exchangers of the activated indoor units, such as the indoor heat exchanger 211, respectively. The low-temperature and low-pressure liquid refrigerant is evaporated into a low-temperature and low-pressure gas refrigerant by absorbing heat of the indoor air, and the indoor air is cooled. The low-temperature and low-pressure gaseous refrigerant leaves the indoor heat exchanger 211, then flows through the corresponding gas pipe connecting branch, the gas pipe header 119, the gas stop valve 118, and the four-way valve 116 in sequence, and then enters the gas-liquid separator 112. The gas-liquid separated refrigerant gas is sucked into the compressor 111 through the suction port. A complete refrigeration cycle is completed and such refrigeration cycle can be performed without interruption in order to achieve the target refrigeration temperature. As shown by arrows in fig. 1, in the heating cycle, the flow direction of the refrigerant in the outdoor unit 11 and the indoor unit 21 is exactly opposite to the flow direction at the time of the cooling cycle, and the outdoor heat exchanger 113 functions as an evaporator and the indoor heat exchanger 211 functions as a condenser.
When the compressor 111 is in operation, the discharge temperature needs to be controlled within a proper range, otherwise when the discharge temperature exceeds a certain temperature value, the compressor is prone to protective shutdown. Therefore, the multi-split air conditioner is provided with an exhaust temperature frequency limiting control program. In order to avoid the technical problem of exhaust temperature frequency limiting program failure under low load, the compressor frequency of the multi-split air conditioner adopts the following control method.
Fig. 2 is a flowchart of a method for controlling a frequency of a compressor of a multi-split air conditioner according to the present invention. As shown in fig. 2, the method for controlling the compressor frequency of the multi-split air conditioner starts, and then detects a real-time start-up load KF of the multi-split air conditioner in step S1. For example, a multi-split air conditioner has four indoor units, and the load powers of the four indoor units are 2.5KW, 3.5KW, and 5.0KW, respectively. When only 3.5KW indoor unit is turned on, the real-time turn-on load KF of the multi-split air conditioner 1 is: KF is 3.5/(2.5+2.5+3.5+5.0) 0.26 × 100% 26%. When two 2.5KW indoor units are turned on, the real-time power-on load KF is: KF ═ (2.5+2.5)/(2.5+2.5+3.5+5) ═ 37%. Thus, the real-time boot load KF varies. In step S2, a first dynamic exhaust temperature threshold and a second exhaust temperature threshold are determined based on the detected real-time startup load KF, wherein the second dynamic exhaust temperature threshold is smaller than the first dynamic exhaust temperature threshold. The first and second dynamic exhaust temperature thresholds are calculated using the following equations (1) and (2), respectively:
first dynamic exhaust temperature threshold +10KF, (1)
Second dynamic exhaust temperature threshold +10KF, (2)
The KF is a real-time starting load of the multi-split air conditioner, and the unit is that the first reference temperature is larger than the second reference temperature and is constant. For example, the first reference temperature is 95 ℃, and the second reference temperature is 85 ℃. For a multi-split air conditioner of different configurations, the first reference temperature and the second reference temperature constant in the formula may be changed, and thus may be other suitable temperature values, and each constant may be determined experimentally. In step S3, a real-time exhaust temperature T of a multi-split air conditioner is measuredd. Real-time exhaust temperature TdTypically measured at a location near the compressor discharge. After determining the first dynamic exhaust temperature threshold, the second dynamic exhaust temperature threshold, and the real-time exhaust temperature TdThereafter, control proceeds to step S4 to map the real-time exhaust temperature TdRespectively, with a first dynamic exhaust temperature threshold and a second dynamic exhaust temperature threshold. In step S5, when the real-time exhaust temperature T is lower than the predetermined valuedWhen the temperature is greater than the first dynamic exhaust temperature threshold value, the compressor is stopped for a first preset time period; and when the real-time exhaust temperature T isdAnd when the temperature is less than or equal to the first dynamic exhaust temperature threshold and greater than the second dynamic exhaust temperature threshold, reducing the frequency of the compressor. The first predetermined period of time is, for example, 1 minute, 2 minutes, or other suitable period of time. The first predetermined period of time may be determined experimentally. The control method is carried out repeatedly at certain time intervals.
Fig. 3 is a flowchart of a method for controlling a frequency of a compressor of a multi-split air conditioner according to a first embodiment of the present invention. As shown in fig. 3, in this embodiment, the control method detects a real-time startup load KF of the one-to-many air conditioner after the start (step S1). Control then proceeds to step S2a where a first dynamic exhaust temperature threshold, a second dynamic exhaust temperature threshold, and a third dynamic exhaust temperature threshold are determined based on the real-time startup load KF. The second dynamic exhaust temperature threshold is smaller than the first dynamic exhaust temperature threshold and larger than the third dynamic exhaust temperature threshold, and the change direction of the first dynamic exhaust temperature threshold, the second dynamic exhaust temperature threshold and the third dynamic exhaust temperature threshold is consistent with the change direction of the real-time startup load. The first dynamic exhaust temperature threshold and the second exhaust temperature threshold may be determined according to equations (1) and (2) above, respectively. The third dynamic exhaust temperature threshold is calculated according to the following equation:
third dynamic exhaust temperature threshold +10KF, (3)
The KF is the real-time starting load of the multi-split air conditioner, and the unit is that the third reference temperature is smaller than the first reference temperature and the second reference temperature and is also a constant. For example, the third reference temperature is 80 ℃ or other suitable temperature value. The third reference temperature in the formula may vary and may be determined experimentally for a multi-split air conditioner of different configurations. The control method measures a real-time exhaust temperature T of the multi-split air conditioner in step S3d. Then, the control method proceeds to step S4 a. In step S4a, the real-time exhaust temperature T is determineddRespectively, with a first dynamic exhaust temperature threshold, a second dynamic exhaust temperature threshold, and a third dynamic exhaust temperature threshold. Different control measures are implemented for the compressor frequency depending on the result of the comparison, and therefore the control method proceeds to step S5 a.
In step S5a, the following control measures are implemented for the compressor frequency. When real-time exhaust temperature TdAbove the first dynamic discharge temperature threshold, the compressor is shutdown for a first predetermined period of time. The first predetermined period of time is, for example, 1 minute, 2 minutes, or other suitable period of time. When real-time exhaust temperature TdAt or below the first dynamic discharge temperature threshold and above the second dynamic discharge temperature threshold, the frequency of the compressor is reduced, for example, toThe compressor frequency is reduced at 0.8Hz/s, 1Hz/s, 2Hz/s, or other suitable speed. When real-time exhaust temperature TdAnd when the temperature is less than or equal to the second dynamic exhaust temperature threshold and greater than the third dynamic exhaust temperature threshold, keeping the frequency of the compressor unchanged.
Fig. 4 is a flowchart of a method for controlling a frequency of a compressor of a multi-split air conditioner according to a second embodiment of the present invention. As shown in fig. 4, in this embodiment, the control method similarly detects the real-time startup load KF of the one-drive-multiple air conditioner after the start (step S1). Control then proceeds to step S2b where a first dynamic exhaust temperature threshold, a second dynamic exhaust temperature threshold, a third dynamic exhaust temperature threshold, and a fourth dynamic exhaust temperature threshold are determined based on the real-time startup load KF. The second dynamic exhaust temperature threshold is less than the first dynamic exhaust temperature threshold and greater than a third dynamic exhaust temperature threshold, which is greater than a fourth dynamic exhaust temperature threshold. The change direction of each of the first dynamic exhaust temperature threshold, the second dynamic exhaust temperature threshold, the third dynamic exhaust temperature threshold and the fourth dynamic exhaust temperature threshold is consistent with the change direction of the real-time startup load KF. The first, second, and third dynamic exhaust temperature thresholds may be determined according to equations (1), (2), and (3) above, respectively. The fourth dynamic exhaust temperature threshold is calculated according to the following equation:
fourth dynamic exhaust temperature threshold +10KF, (4)
The KF is a real-time starting load of the multi-split air conditioner, and the unit is that the fourth reference temperature is smaller than the fourth reference temperature and is also a constant. For example, the fourth reference temperature is 75 ℃ or other suitable temperature value. The fourth reference temperature in the formula may vary and may be determined experimentally for a multi-split air conditioner of different configurations. The control method then proceeds to step S3. The real-time exhaust temperature T of the multi-split air conditioner is measured in step S3d. Then, the control method proceeds to step S4 b. In step S4b, the real-time exhaust temperature T is determineddRespectively corresponding to the first dynamic exhaust temperature threshold value and the second dynamic exhaust temperatureThe degree threshold, the third dynamic exhaust temperature threshold, and the fourth dynamic exhaust temperature threshold are compared. Different control measures are implemented for the compressor frequency depending on the result of the comparison, and therefore the control method proceeds to step S5 b.
In step S5b, the following control measures are implemented for the compressor frequency. When real-time exhaust temperature TdAbove the first dynamic discharge temperature threshold, the compressor is shutdown for a first predetermined period of time. The first predetermined period of time is, for example, 1 minute, 2 minutes, or other suitable period of time. When real-time exhaust temperature TdLess than or equal to the first dynamic discharge temperature threshold and greater than the second dynamic discharge temperature threshold, the frequency of the compressor is decreased, such as at 0.8Hz/s, 1Hz/s, 2Hz/s, or other suitable rate. When real-time exhaust temperature TdAnd when the temperature is less than or equal to the second dynamic exhaust temperature threshold and greater than the third dynamic exhaust temperature threshold, keeping the frequency of the compressor unchanged. When real-time exhaust temperature TdAnd when the temperature is less than or equal to the third dynamic exhaust temperature threshold and is greater than the fourth dynamic exhaust temperature threshold, the multi-split air conditioner enters a compressor frequency automatic control mode, namely the multi-split air conditioner enters the compressor frequency automatic control mode based on the indoor cooling/heating requirement.
Fig. 5 is a first part of a flowchart of a third embodiment of a control method of a compressor frequency of a multi-split air conditioner according to the present invention, and fig. 6 is a second part of a flowchart of a third embodiment of a control method of a compressor frequency of a multi-split air conditioner according to the present invention. As shown in fig. 5, in this embodiment, the control method also detects the real-time startup load KF of the multi-split air conditioner after the start (step S1). Then, the control method proceeds to step S2 c. In step S2c, a first dynamic exhaust temperature threshold T is determined based on the real-time startup load KFt1Second additional dynamic exhaust temperature threshold Tt2A second dynamic exhaust temperature threshold Tt3A third dynamic exhaust temperature threshold Tt4And a fourth dynamic exhaust temperature threshold Tt5. First dynamic exhaust temperature threshold Tt1Second additional dynamic exhaust temperature threshold Tt2A second dynamic exhaust temperature threshold Tt3A third dynamic exhaust temperature threshold Tt4And a fourth dynamic exhaust temperature threshold Tt5The size sequence of (A) is as follows:
Tt1>Tt2>Tt3>Tt4>Tt5，
the change direction of each of the first dynamic exhaust temperature threshold, the second additional dynamic exhaust temperature threshold, the second dynamic exhaust temperature threshold, the third dynamic exhaust temperature threshold and the fourth dynamic exhaust temperature threshold is consistent with the change direction of the real-time startup load KF. The first, second, third, and fourth dynamic exhaust temperature thresholds may be determined according to equations (1), (2), (3), and (4) above, respectively. The second additional dynamic exhaust temperature threshold is calculated according to the following equation:
second additional dynamic exhaust temperature threshold +10KF, (5)
The KF is a real-time starting load of the multi-split air conditioner, and the unit is that the second additional reference temperature is a constant which is smaller than the first reference temperature and larger than the second reference temperature. For example, the second additional reference temperature is 90 ℃ or other suitable temperature value. The second additional reference temperature in the formula may vary and may be determined experimentally for a different configuration of a multi-split air conditioner. The control method then proceeds to step S3. The real-time exhaust temperature T of the multi-split air conditioner is measured in step S3d. The control method then proceeds to step S41.
As shown in fig. 5, in step S41, the real-time exhaust temperature T is setdAnd a first dynamic exhaust temperature threshold Tt1A comparison is made. If the real-time exhaust temperature TdLess than or equal to the first dynamic exhaust temperature threshold Tt1Control proceeds to step S42. If the real-time exhaust temperature TdGreater than a first dynamic exhaust temperature threshold Tt1Control proceeds to step S51 to shutdown the compressor. After a first predetermined period of time, such as 2 minutes or other suitable period of time, has elapsed after the compressor shutdown, control proceeds to step 61, where the compressor is restarted and the actual values are remeasuredTime exhaust temperature Td. Control then continues to step S71 to determine the current TdAnd a first dynamic exhaust temperature threshold Tt1A comparison is made. If T is currently obtaineddLess than or equal to the first dynamic exhaust temperature threshold Tt1Control proceeds to step S42. If T is currently obtaineddStill greater than the first dynamic exhaust temperature threshold Tt1Control proceeds to step S81 to again shutdown the compressor for a second predetermined period of time, e.g., 3 minutes or other suitable period of time, longer than the first predetermined period of time. After the second predetermined period of time has elapsed, control proceeds to step S91 where it is determined whether the number of restarts of the compressor during a third predetermined period of time (e.g., 1 hour or other suitable time) is less than a predetermined number of times, e.g., 3 times. The third predetermined period of time is longer than the second predetermined period of time. If the number of times of restarting the compressor has reached the predetermined number of times, the control method proceeds to step S121 to issue a malfunction alert, which indicates that a high frequency exhaust malfunction exists in the multi-split air conditioner. If the number of restarts of the compressor is less than the predetermined number, the control method proceeds to step S101 to restart the compressor and then operate the compressor at a preset low frequency for a fourth predetermined period of time, for example, 3 minutes or other suitable period of time (step S111). After the compressor low frequency operation continues for the fourth predetermined period of time, control returns to step S1.
As shown in fig. 5, if the real-time exhaust temperature T isdLess than or equal to the first dynamic exhaust temperature threshold Tt1Control proceeds to step S42. In step S42, the real-time exhaust temperature T is setdAnd a second additional dynamic exhaust temperature threshold Tt2A comparison is made. If the real-time exhaust temperature TdLess than or equal to a second additional dynamic exhaust temperature threshold Tt2Control proceeds to step S43. If the real-time exhaust temperature TdGreater than a second supplemental dynamic exhaust temperature threshold Tt2Control proceeds to step S52 to decrease the frequency of the compressor at a higher rate, such as 2 Hz/S. After the compressor has been down-clocked for a fifth predetermined period of time, e.g., 10 seconds, 20 seconds, or otherAfter an appropriate period of time, control proceeds to step S62 to re-measure the real-time exhaust temperature Td. Control then continues to step S72 to determine the current TdAnd a second additional dynamic exhaust temperature threshold Tt2A comparison is made. If T is currently obtaineddLess than or equal to a second additional dynamic exhaust temperature threshold Tt2Control proceeds to step S43. If T is currently obtaineddStill greater than the second supplemental dynamic exhaust temperature threshold Tt2Control returns to step S52 to re-implement the frequency reduction measure.
As shown in fig. 6, if the real-time exhaust temperature T isdLess than or equal to a second additional dynamic exhaust temperature threshold Tt2Control proceeds to step S43. In step S43, the real-time exhaust temperature T is setdAnd a second dynamic exhaust temperature threshold Tt3A comparison is made. If the real-time exhaust temperature TdLess than or equal to the second dynamic exhaust temperature threshold Tt3Control proceeds to step S44. If the real-time exhaust temperature TdGreater than a second dynamic exhaust temperature threshold Tt3Control proceeds to step S53. In step S53, the frequency of the compressor is decreased at a lower speed, for example, at a speed of 1 Hz/S. After the compressor has been down-cycled for a fifth predetermined period of time, such as 10 seconds, 20 seconds, or other suitable period of time, control proceeds to step S63 where the real-time discharge temperature T is re-measuredd. Control then continues to step S73 to determine the current TdAnd a second dynamic exhaust temperature threshold Tt3A comparison is made. If T is currently obtaineddLess than or equal to a second additional dynamic exhaust temperature threshold Tt2Control proceeds to step S44. If T is currently obtaineddStill greater than the second dynamic exhaust temperature threshold Tt3Control returns to step S53 to re-implement the frequency reduction measure.
As shown in fig. 6, if the real-time exhaust temperature T isdLess than or equal to the second dynamic exhaust temperature threshold Tt3Control proceeds to step S44. In step S44, the real-time exhaust temperature is adjustedTdAnd a third dynamic exhaust temperature threshold Tt4A comparison is made. If the real-time exhaust temperature TdLess than or equal to a third dynamic exhaust temperature threshold Tt4Control proceeds to step S45. If the real-time exhaust temperature TdGreater than a third dynamic exhaust temperature threshold Tt4The control method proceeds to step S54 to keep the frequency of the compressor constant.
As shown in fig. 6, if the real-time exhaust temperature T isdLess than or equal to a third dynamic exhaust temperature threshold Tt4Control proceeds to step S45. In step S45, the real-time exhaust temperature T is setdAnd a fourth dynamic exhaust temperature threshold Tt5A comparison is made. If the real-time exhaust temperature TdGreater than a fourth dynamic exhaust temperature threshold Tt5The control method proceeds to step S56 where the multi-split air conditioner enters a normal control mode, i.e., enters an automatic compressor frequency control based on the indoor cooling/heating demand. If the real-time exhaust temperature TdLess than or equal to a fourth dynamic exhaust temperature threshold Tt5Control proceeds to step S55. In step S55, the frequency of the compressor is increased at a predetermined rate, for example, decreased at 1Hz/S or other suitable rate. After the compressor has been upscaled for a sixth predetermined period of time, such as 10 seconds, 20 seconds, or other suitable period of time, control proceeds to step S65 where the real-time discharge temperature T is re-measuredd. Control then continues to step S75 to determine the current TdAnd a fourth dynamic exhaust temperature threshold Tt5A comparison is made. If T is currently obtaineddGreater than a fourth dynamic exhaust temperature threshold Tt5The control method proceeds to step S56 and the multi-split air conditioner enters the normal control mode. If T is currently obtaineddStill less than or equal to the fourth dynamic exhaust temperature threshold Tt3Control returns to step S55 to re-implement the frequency boosting.
So far, the technical solutions of the present invention have been described in connection with the preferred embodiments shown in the drawings, but it is easily understood by those skilled in the art that the scope of the present invention is obviously not limited to these specific embodiments. Equivalent changes or substitutions of related technical features can be made by those skilled in the art without departing from the principle of the invention, and the technical scheme after the changes or substitutions can fall into the protection scope of the invention.
Claims (10)
1. A method for controlling a frequency of a compressor of a multi-split air conditioner, wherein the multi-split air conditioner includes a variable frequency compressor, and the method comprises:
detecting a real-time starting load KF of the multi-split air conditioner;
at least determining a first dynamic exhaust temperature threshold and a second dynamic exhaust temperature threshold smaller than the first dynamic exhaust temperature threshold based on the real-time startup load KF;
measuring a real-time discharge temperature T of the compressord；
Setting the real-time exhaust temperature TdComparing with the first dynamic exhaust temperature threshold and the second dynamic exhaust temperature threshold, respectively;
when the real-time exhaust temperature TdGreater than the first dynamic discharge temperature threshold, the compressor is shutdown for a first predetermined period of time; and when the real-time exhaust temperature T isdReducing the frequency of the compressor when the first dynamic discharge temperature threshold is less than or equal to the first dynamic discharge temperature threshold and greater than the second dynamic discharge temperature threshold,
and the change direction of the first dynamic exhaust temperature threshold and the second dynamic exhaust temperature threshold is consistent with the change direction of the real-time startup load KF.
2. The method for controlling a frequency of compressors of a multi-split air conditioner according to claim 1, further comprising:
determining a third dynamic exhaust temperature threshold based on the real-time startup load KF, wherein the third dynamic exhaust temperature threshold is smaller than the second dynamic exhaust temperature threshold;
setting the real-time exhaust temperature TdAnd the third dynamic exhaustComparing the temperature thresholds;
when the real-time exhaust temperature TdGreater than the third dynamic discharge temperature threshold and less than or equal to the second dynamic discharge temperature threshold, maintaining the frequency of the compressor constant,
and the change direction of the third dynamic exhaust temperature threshold value is consistent with the change direction of the real-time startup load KF.
3. The method for controlling a frequency of compressors of a multi-split air conditioner according to claim 2, further comprising:
determining a fourth dynamic exhaust temperature threshold based on the real-time startup load KF, wherein the fourth dynamic exhaust temperature threshold is smaller than the third dynamic exhaust temperature threshold;
setting the real-time exhaust temperature TdComparing to the fourth dynamic exhaust temperature threshold;
when the real-time exhaust temperature TdWhen the temperature is greater than the fourth dynamic exhaust temperature threshold and less than or equal to the third dynamic exhaust temperature threshold, the multi-split air conditioner enters a compressor frequency automatic control mode; and when the real-time exhaust temperature T isdIncreasing the frequency of the compressor when the dynamic discharge temperature is less than or equal to a fourth dynamic discharge temperature threshold,
and the change direction of the fourth dynamic exhaust temperature threshold is consistent with the change direction of the real-time startup load KF.
4. The method for controlling a frequency of compressors of a multi-split air conditioner according to claim 3, further comprising:
determining a second additional dynamic exhaust temperature threshold based on the real-time startup load KF, wherein the second additional dynamic exhaust temperature threshold is less than or equal to the first dynamic exhaust temperature threshold and greater than the second dynamic exhaust temperature threshold;
setting the real-time exhaust temperature TdComparing to the second additional dynamic exhaust temperature threshold;
when the real-time exhaust temperature TdWhen the temperature is greater than the second additional dynamic exhaust temperature threshold and less than or equal to the first dynamic exhaust temperature threshold, reducing the frequency of the compressor at a higher speed; and when the real-time exhaust temperature T isdGreater than the second dynamic discharge temperature threshold and less than or equal to the second additional dynamic discharge temperature threshold, reducing the frequency of the compressor at a slower speed,
and the change direction of the second additional dynamic exhaust temperature threshold is consistent with the change direction of the real-time startup load KF.
5. A control method of compressor frequency of a multi-split air conditioner as claimed in any one of claims 1 to 4, wherein after the compressor is stopped for a first predetermined period of time, the compressor is restarted and the real time discharge temperature T is re-measureddAnd the current real-time exhaust temperature T is measureddComparing with the first dynamic exhaust temperature threshold if the real-time exhaust temperature TdGreater than the first dynamic discharge temperature threshold, the compressor is shutdown for a second predetermined period of time, the second predetermined period of time being greater than the first predetermined period of time.
6. The method for controlling a frequency of compressors of a multi-split air conditioner according to claim 5, wherein after the compressor is stopped for a second predetermined period of time, the method further comprises:
judging whether the restarting frequency of the compressor in a third preset time period is smaller than a preset frequency, wherein the preset frequency is not less than 3;
restarting the compressor and operating the compressor at a low frequency for a fourth predetermined period of time if the number of restarts is less than a predetermined number;
if the number of restarts reaches the predetermined number, issuing a high frequency exhaust fault alert,
wherein the second predetermined period of time is greater than the first predetermined period of time and less than the third predetermined period of time.
7. The method as set forth in claim 1, wherein the real-time discharge temperature Td is re-measured and the current real-time discharge temperature T is measured after a fifth predetermined period of time after the frequency of the compressor is lowereddComparing with the second dynamic exhaust temperature threshold if the real-time exhaust temperature TdAnd if the second dynamic discharge temperature threshold is greater than the first dynamic discharge temperature threshold, repeating the step of reducing the frequency of the compressor.
8. The method as set forth in claim 3, wherein the real-time discharge temperature Td is re-measured and the current real-time discharge temperature Td is measured after a sixth predetermined period of time after the frequency of the compressor is increased, and the current real-time discharge temperature T is measureddComparing with the fourth dynamic exhaust temperature threshold if the real-time exhaust temperature TdAnd repeating the step of increasing the frequency of the compressor if the fourth dynamic discharge temperature threshold is less than or equal to.
9. The method for controlling a compressor frequency of a multi-split air conditioner according to claim 4, wherein the first dynamic discharge temperature threshold, the second additional dynamic discharge temperature threshold, the second dynamic discharge temperature threshold, the third dynamic discharge temperature threshold, and the fourth dynamic discharge temperature threshold are calculated based on the following formulas, respectively:
the first dynamic exhaust gas temperature threshold is equal to the first reference temperature +10KF (1),
the second dynamic exhaust gas temperature threshold is equal to the second reference temperature +10KF (2),
the third dynamic exhaust gas temperature threshold is the third reference temperature +10KF (3),
the fourth dynamic exhaust gas temperature threshold is the fourth reference temperature +10KF (4),
the second additional dynamic exhaust temperature threshold is the second additional reference temperature +10KF (5), wherein KF is the real-time starting load of the multi-split air conditioner, and the unit is,
the first reference temperature > the second additional reference temperature > the second reference temperature > the third reference temperature > the fourth reference temperature, and are all constant.
10. A multi-split air conditioner characterized in that the multi-split air conditioner includes a variable frequency compressor, and the multi-split air conditioner controls the frequency of the compressor using the control method according to any one of claims 1 to 9.
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| PCT/CN2022/081225 WO2022194218A1 (en) | 2021-03-16 | 2022-03-16 | Method for controlling frequency of compressor of multi-split air conditioner, and multi-split air conditioner |
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| WO2022194218A1 (en) * | 2021-03-16 | 2022-09-22 | 青岛海尔空调电子有限公司 | Method for controlling frequency of compressor of multi-split air conditioner, and multi-split air conditioner |
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