CN110749039A

CN110749039A - Control method and device of multi-split system, storage medium and multi-split system

Info

Publication number: CN110749039A
Application number: CN201910988631.1A
Authority: CN
Inventors: 刘杰; 华洪香; 孙燕佳; 覃琨; 陈代兵; 关福成; 刘雄
Original assignee: Gree Electric Appliances Inc of Zhuhai
Current assignee: Gree Electric Appliances Inc of Zhuhai
Priority date: 2019-10-17
Filing date: 2019-10-17
Publication date: 2020-02-04
Anticipated expiration: 2039-10-17
Also published as: CN110749039B

Abstract

The invention discloses a control method and a control device of a multi-split system, a storage medium and the multi-split system, wherein the method comprises the following steps: determining whether the multi-split system is in a load conversion stage; if the multi-split system is in the load conversion stage, determining whether the temperature of a coil of an operating indoor unit in the multi-split system is greater than or equal to the upper limit of the set heating overload temperature range; and if the temperature of the coil pipe of the running indoor unit in the multi-split air-conditioning system is greater than or equal to the upper limit of the set heating overload temperature range, controlling the opening of a refrigerant throttling device of the shutdown indoor unit in the multi-split air-conditioning system, so that part of the refrigerant which needs to flow to the running indoor unit is changed into the refrigerant which flows to the shutdown indoor unit and then flows back to the outdoor heat exchanger of the multi-split air-conditioning system. The scheme of the invention can solve the problem that the running reliability is influenced by the fact that the running indoor unit of the air-conditioning multi-connected unit is easy to overload and protect shutdown when the heating load is changed, and achieves the effect of improving the running reliability.

Description

Control method and device of multi-split system, storage medium and multi-split system

Technical Field

The invention belongs to the technical field of air conditioners, and particularly relates to a control method and device of a multi-split air-conditioning system, a storage medium and the multi-split air-conditioning system, in particular to a control method and device for preventing the multi-split air-conditioning system from being subjected to overheating protection, a storage medium and the multi-split air-conditioning system.

Background

Air conditioner multi-connected unit contains: at least two indoor units connected in parallel, one or more outdoor units connected in parallel, and a refrigerant circulation connection pipe between the outdoor unit and each indoor unit. Each indoor unit comprises an electronic expansion valve and an indoor heat exchanger, one end of the electronic expansion valve is connected to an exhaust pipe of the outer compressor through a refrigerant circulating pipe, the other end of the electronic expansion valve is connected with one end of the indoor heat exchanger, and the other end of the indoor heat exchanger is connected to an air suction pipe of the outer compressor through the refrigerant circulating pipe.

When the multi-connected unit operates in a heating mode, the temperature of a coil pipe of a heat exchanger of the indoor unit needs to reach a certain height so as to ensure the heating effect. However, when the temperature of the coil pipe is too hot, the gaseous refrigerant in the coil pipe cannot be liquefied by heat release, so that the pressure of the system is continuously increased, and the high-pressure fault of the air conditioning system is easy to occur.

The above is only for the purpose of assisting understanding of the technical aspects of the present invention, and does not represent an admission that the above is prior art.

Disclosure of Invention

The invention aims to provide a control method and device of a multi-connected unit system, a storage medium and the multi-connected unit system aiming at the defects, so as to solve the problem that when the heating load of an air-conditioning multi-connected unit in high-load heating operation is changed, the operation of an indoor unit is easy to overload to protect shutdown, and the operation reliability of the air-conditioning multi-connected unit is influenced, and achieve the effect of improving the operation reliability of the air-conditioning multi-connected unit.

The invention provides a control method of a multi-split system, which comprises the following steps: determining whether the multi-split system is in a load conversion stage; if the multi-split system is in the load conversion stage, determining whether the temperature of a coil of an operating indoor unit in the multi-split system is greater than or equal to the upper limit of the set heating overload temperature range; and if the temperature of the coil pipe of the running indoor unit in the multi-split air-conditioning system is greater than or equal to the upper limit of the set heating overload temperature range, controlling the opening of a refrigerant throttling device of the shutdown indoor unit in the multi-split air-conditioning system, so that part of the refrigerant which needs to flow to the running indoor unit is changed into the refrigerant which flows to the shutdown indoor unit and then flows back to the outdoor heat exchanger of the multi-split air-conditioning system.

Optionally, determining whether the multi-split system is in a load conversion stage includes: determining whether the multi-split system is operated in a heating mode; if the multi-split system operates in the heating mode, determining whether the whole multi-split system operates in an overload mode; if the whole multi-split system runs in an overload mode, determining whether the load of the multi-split system changes suddenly; and if the load of the multi-split system is suddenly changed, determining that the multi-split system is in a load conversion stage.

Optionally, the determining whether the entire multi-split system is in overload operation includes: determining whether the outdoor environment temperature of the environment to which the multi-split air-conditioning system belongs is within a set outdoor temperature range; if the outdoor environment temperature of the environment to which the multi-split air-conditioning system belongs is within the set outdoor temperature range, determining whether the set temperature of the running indoor unit of the multi-split air-conditioning system and the temperature difference value of the indoor environment temperature of the environment to which the multi-split air-conditioning system belongs are larger than or equal to a set temperature threshold value; if the temperature difference between the set temperature of the running internal machine of the multi-split air-conditioning system and the indoor environment temperature of the environment to which the multi-split air-conditioning system belongs is greater than or equal to the set temperature threshold, determining whether the continuous running time of the whole multi-split air-conditioning system is greater than or equal to the set time; if the continuous operation time of the complete machine of the multi-split system is longer than or equal to the set time, determining the complete machine of the multi-split system to operate in an overload mode; and/or, determining whether the load of the multi-split air conditioning system is mutated, comprising: determining whether the number of running internal machines of the multi-split air-conditioning system is reduced and is greater than or equal to the set minimum running number; and if the number of the running internal machines of the multi-split air-conditioning system is reduced and is greater than or equal to the set minimum running number, determining that the load of the multi-split air-conditioning system is suddenly changed.

Optionally, determining whether the coil temperature of the indoor unit operating in the multi-split air conditioning system is greater than or equal to the upper limit of the set heating overload temperature range includes: determining one running internal machine with the highest coil pipe temperature in all running internal machines in the multi-split air-conditioning system; determining whether the rate of change of the coil temperature of the one operating machine is greater than or equal to the upper limit of the set rate of change range; and if the change rate of the coil temperature of the one running indoor unit is greater than or equal to the upper limit of the set change rate range, determining that the coil temperature of the running indoor unit in the multi-split air-conditioning system is greater than or equal to the upper limit of the set heating overload temperature range.

Optionally, the controlling the opening degree of a refrigerant throttling device of a shutdown internal machine in the multi-split air conditioning system includes: determining the current change rate interval of the change rate of the coil temperature of the running internal machine within the set change rate range; according to a first set relation between a set change rate section and a set opening degree, determining the set opening degree corresponding to the set change rate section which is the same as the current change rate section in the first set relation, and the set opening degree is a first opening degree required to be increased by a refrigerant throttling device corresponding to the current change rate section; the current opening degree of a refrigerant throttling device of a shutdown internal machine in the multi-online system is adjusted to be the first opening degree; and/or determining the current temperature interval of the coil temperature of the running internal machine in the set heating overload temperature range; according to a second set relationship between the set temperature interval and the set opening degree, determining the set opening degree corresponding to the same set temperature interval as the current temperature interval in the second set relationship, and the set opening degree is the second opening degree required to be increased by the refrigerant throttling device corresponding to the current temperature interval; and the current opening degree of a refrigerant throttling device of the shutdown internal machine in the multi-online system is adjusted to the second opening degree.

Optionally, the method further comprises: after controlling the opening degree of a refrigerant throttling device of a shutdown indoor unit in the multi-split air conditioning system, determining whether the temperature of a coil pipe of the running indoor unit in the multi-split air conditioning system is reduced to be smaller than the lower limit of a set heating overload temperature range; if the temperature of a coil pipe of an operating indoor unit in the multi-split air-conditioning system is reduced to be smaller than the lower limit of the set heating overload temperature range, stopping controlling the opening of a refrigerant throttling device of a shutdown indoor unit in the multi-split air-conditioning system; wherein, shut down the refrigerant throttling arrangement of interior machine, include: an electronic expansion valve or a capillary tube.

In accordance with the above method, another aspect of the present invention provides a control apparatus for a multi-split air conditioning system, including: the determining unit is used for determining whether the multi-split system is in a load conversion stage; the determining unit is further used for determining whether the temperature of a coil of an operating indoor unit in the multi-split system is greater than or equal to the upper limit of the set heating overload temperature range or not if the multi-split system is in the load conversion stage; and the control unit is used for controlling the opening degree of a refrigerant throttling device of the shutdown indoor unit in the multi-split system if the temperature of the coil pipe of the running indoor unit in the multi-split system is greater than or equal to the upper limit of the set heating overload temperature range, so that part of the refrigerant which should flow to the running indoor unit is changed into the refrigerant which flows to the shutdown indoor unit and then flows back to the outdoor heat exchanger of the multi-split system.

Optionally, the determining unit determines whether the multi-split system is in a load conversion stage, including: determining whether the multi-split system is operated in a heating mode; if the multi-split system operates in the heating mode, determining whether the whole multi-split system operates in an overload mode; if the whole multi-split system runs in an overload mode, determining whether the load of the multi-split system changes suddenly; and if the load of the multi-split system is suddenly changed, determining that the multi-split system is in a load conversion stage.

Optionally, the determining unit determines whether a complete machine of the multi-split system is running under overload, including: determining whether the outdoor environment temperature of the environment to which the multi-split air-conditioning system belongs is within a set outdoor temperature range; if the outdoor environment temperature of the environment to which the multi-split air-conditioning system belongs is within the set outdoor temperature range, determining whether the set temperature of the running indoor unit of the multi-split air-conditioning system and the temperature difference value of the indoor environment temperature of the environment to which the multi-split air-conditioning system belongs are larger than or equal to a set temperature threshold value; if the temperature difference between the set temperature of the running internal machine of the multi-split air-conditioning system and the indoor environment temperature of the environment to which the multi-split air-conditioning system belongs is greater than or equal to the set temperature threshold, determining whether the continuous running time of the whole multi-split air-conditioning system is greater than or equal to the set time; if the continuous operation time of the complete machine of the multi-split system is longer than or equal to the set time, determining the complete machine of the multi-split system to operate in an overload mode; and/or the determining unit determines whether the load of the multi-split air conditioning system is suddenly changed, and comprises the following steps: determining whether the number of running internal machines of the multi-split air-conditioning system is reduced and is greater than or equal to the set minimum running number; and if the number of the running internal machines of the multi-split air-conditioning system is reduced and is greater than or equal to the set minimum running number, determining that the load of the multi-split air-conditioning system is suddenly changed.

Optionally, the determining unit determines whether the coil temperature of the running indoor unit in the multi-split air-conditioning system is greater than or equal to the upper limit of the set heating overload temperature range, and includes: determining one running internal machine with the highest coil pipe temperature in all running internal machines in the multi-split air-conditioning system; determining whether the rate of change of the coil temperature of the one operating machine is greater than or equal to the upper limit of the set rate of change range; and if the change rate of the coil temperature of the one running indoor unit is greater than or equal to the upper limit of the set change rate range, determining that the coil temperature of the running indoor unit in the multi-split air-conditioning system is greater than or equal to the upper limit of the set heating overload temperature range.

Optionally, the controlling unit controls an opening degree of a refrigerant throttling device of a shutdown internal machine in the multi-split air conditioning system, and includes: determining the current change rate interval of the change rate of the coil temperature of the running internal machine within the set change rate range; according to a first set relation between a set change rate section and a set opening degree, determining the set opening degree corresponding to the set change rate section which is the same as the current change rate section in the first set relation, and the set opening degree is a first opening degree required to be increased by a refrigerant throttling device corresponding to the current change rate section; the current opening degree of a refrigerant throttling device of a shutdown internal machine in the multi-online system is adjusted to be the first opening degree; and/or determining the current temperature interval of the coil temperature of the running internal machine in the set heating overload temperature range; according to a second set relationship between the set temperature interval and the set opening degree, determining the set opening degree corresponding to the same set temperature interval as the current temperature interval in the second set relationship, and the set opening degree is the second opening degree required to be increased by the refrigerant throttling device corresponding to the current temperature interval; and the current opening degree of a refrigerant throttling device of the shutdown internal machine in the multi-online system is adjusted to the second opening degree.

Optionally, the method further comprises: the determining unit is further used for determining whether the temperature of a coil pipe of the running internal machine in the multi-split air-conditioning system is reduced to be smaller than the lower limit of the set heating overload temperature range after controlling the opening degree of a refrigerant throttling device of the shutdown internal machine in the multi-split air-conditioning system; the control unit is also used for stopping controlling the opening degree of a refrigerant throttling device of the shutdown indoor unit in the multi-split air-conditioning system if the temperature of a coil pipe of the running indoor unit in the multi-split air-conditioning system is reduced to be smaller than the lower limit of the set heating overload temperature range; wherein, shut down the refrigerant throttling arrangement of interior machine, include: an electronic expansion valve or a capillary tube.

In accordance with another aspect of the present invention, there is provided a multi-split system, including: the control device of the multi-split system is described above.

In accordance with the above method, a further aspect of the present invention provides a storage medium comprising: the storage medium has stored therein a plurality of instructions; the instructions are used for loading and executing the control method of the multi-split system by the processor.

In accordance with the above method, a further aspect of the present invention provides a multi-split system, including: a processor for executing a plurality of instructions; a memory to store a plurality of instructions; the instructions are stored in the memory, and loaded by the processor and execute the control method of the multi-split system.

According to the scheme of the invention, as long as the condition of closing the indoor unit is related to the heating mode operation of the multi-connected air conditioning unit, the opening of all the stopped electronic expansion valves is opened according to the fixed opening, so that additional indoor and outdoor unit refrigerant connecting pipelines are not required to be added, the existing indoor and outdoor unit refrigerant passages are utilized, the phenomenon of heating overload protection stopping is avoided easily occurring during multi-connected air conditioning unit load conversion in the heating mode and under an overload working condition, and the operation reliability of the multi-connected air conditioning unit is improved.

Furthermore, according to the scheme of the invention, the temperature of the coil pipe of the running indoor unit is reduced by adjusting the opening of the electronic expansion valve of the shutdown indoor unit, and the running reliability and the user experience of the air conditioner are improved.

Furthermore, according to the scheme of the invention, the opening of the electronic expansion valve of the indoor unit for stopping the multi-split air conditioner is controlled to be a certain opening on the basis of the original stopping opening, so that the reliability and the stability of the overheating protection are improved.

Furthermore, according to the scheme of the invention, when the heating load of the multi-connected air conditioner unit is converted, a part of refrigerant is distributed to the side of the shutdown indoor unit by using a pipeline for connecting the heat exchanger of the shutdown indoor unit with the compressor, so that the refrigerant circulation of the running indoor unit is quickly reduced in a short time, the effect of reducing the temperature of the inner pipe of the running indoor unit is achieved, the risk of shutdown of the running indoor unit under the condition of heat overload protection is reduced, the running reliability is good, and the user comfort level experience is good.

Furthermore, according to the scheme of the invention, when the load of the heating multi-split air-conditioning system is converted, the temperature of the coil pipe of the running indoor unit is suddenly increased, and at the moment, the electronic expansion valve of the shutdown indoor unit is opened, so that a part of high-temperature refrigerant which originally flows to the running indoor unit quickly flows to the shutdown indoor unit heat exchanger and then directly flows back to the outdoor heat exchanger, the temperature of the coil pipe of the running indoor unit can be quickly reduced, the problem that the running indoor unit is easy to overload to protect shutdown when the heating load is converted is effectively avoided, and the running reliability is.

Therefore, according to the scheme of the invention, when the temperature of the coil pipe of the running indoor unit is suddenly increased during the load conversion of the heating multi-connected unit system, a part of high-temperature refrigerant which originally flows to the running indoor unit quickly flows to the heat exchanger of the running indoor unit and then directly flows back to the outdoor heat exchanger by opening the electronic expansion valve of the shutdown indoor unit, so that the problems that the running indoor unit is easy to overload to protect shutdown and the running reliability of the air-conditioning multi-connected unit is influenced during the load conversion of the heating load of the high-load heating running air-conditioning multi-connected unit are solved, and the effect of improving the running reliability.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.

Drawings

Fig. 1 is a schematic flowchart illustrating a control method of a multi-split system according to an embodiment of the present invention;

fig. 2 is a schematic flow chart illustrating an embodiment of determining whether a multi-split system is in a load transfer phase according to the method of the present invention;

FIG. 3 is a schematic flow chart illustrating an embodiment of determining whether the overall multi-split system is operating under overload in the method of the present invention;

fig. 4 is a schematic flow chart of an embodiment of determining whether the load of the multi-split system has a sudden change in the method of the present invention;

FIG. 5 is a schematic flow chart illustrating one embodiment of the method of the present invention for determining whether the coil temperature of an operating indoor unit in a multiple split air conditioning system is greater than or equal to the upper limit of the set heating overload temperature range;

fig. 6 is a schematic flow chart illustrating an embodiment of controlling the opening of the refrigerant throttling device of the shutdown internal machine according to the temperature of the coil in the method of the present invention;

FIG. 7 is a flowchart illustrating an embodiment of controlling an opening of a refrigerant throttling device of a shutdown internal machine according to a rate of change of a temperature of a coil according to the method of the present invention;

fig. 8 is a schematic flow chart illustrating an embodiment of exit control of the opening degree of the refrigerant throttling device of the shutdown internal machine in the multiple on-line system according to the method of the present invention;

fig. 9 is a schematic structural diagram of an embodiment of a control apparatus of a multi-split system according to the present invention;

FIG. 10 is a schematic structural diagram of an embodiment of an air conditioning system of the present invention;

FIG. 11 is a schematic diagram of the overheat protection logic of an embodiment of the air conditioning system of the present invention;

FIG. 12 is a schematic diagram of the overheat protection logic for another embodiment of the air conditioning system of the present invention;

FIG. 13 is a logic diagram illustrating overall load determination for an air conditioning system according to an embodiment of the present invention;

FIG. 14 is a schematic diagram illustrating an indoor unit coil temperature determination logic according to an embodiment of the air conditioning system of the present invention;

FIG. 15 is a schematic view of the electronic expansion valve opening control during load shifting of an embodiment of the air conditioning system of the present invention;

fig. 16 is a schematic diagram of the opening control of the electronic expansion valve during load transfer according to another embodiment of the air conditioning system of the present invention.

The reference numbers in the embodiments of the present invention are as follows, in combination with the accompanying drawings:

102-a determination unit; 104-control unit.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the specific embodiments of the present invention and the accompanying drawings. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

According to an embodiment of the present invention, a method for controlling a multi-split system is provided, as shown in fig. 1, which is a schematic flow chart of an embodiment of the method of the present invention. The control method of the multi-split system may include: step S110 to step S130.

At step S110, it is determined whether the multi-split air conditioning system is in a load conversion phase. The load conversion stage refers to a situation that a load suddenly changes when the multi-split air conditioning system operates, for example, the situation that the load suddenly changes when an internal unit is turned off when the multi-split air conditioning system operates in a heating mode.

Optionally, a specific process of determining whether the multi-split air-conditioning system is in the load conversion stage in step S110, and steps S210 to S240, may be further described with reference to a flowchart of an embodiment of determining whether the multi-split air-conditioning system is in the load conversion stage in the method of the present invention shown in fig. 2.

Step S210, determining whether the multi-split system is operating in a heating mode.

For example: and confirming the mode. And judging whether the operation mode of the multi-connected air conditioning unit is the heating mode operation.

Step S220, if the multi-split air-conditioning system is operating in the heating mode, determining whether the whole multi-split air-conditioning system is operating in an overload mode.

More optionally, the specific process of determining whether the complete machine of the multi-split air-conditioning system is in the overload operation in step S220 may further be described with reference to a flowchart of an embodiment of determining whether the complete machine of the multi-split air-conditioning system is in the overload operation in the method shown in fig. 3, where the specific process may include: step S310 to step S340.

Step S310, determining whether the outdoor environment temperature of the environment to which the multi-split air conditioning system belongs is within the set outdoor temperature range.

Step S320, if the outdoor ambient temperature of the environment to which the multi-split air-conditioning system belongs is within the set outdoor temperature range, determining whether a temperature difference between the set temperature of the operating indoor unit of the multi-split air-conditioning system and the indoor ambient temperature of the environment to which the multi-split air-conditioning system belongs is greater than or equal to a set temperature threshold.

Step S330, if the temperature difference between the set temperature of the running internal machine of the multi-split air-conditioning system and the indoor environment temperature of the environment to which the multi-split air-conditioning system belongs is greater than or equal to the set temperature threshold, determining whether the continuous running time of the whole multi-split air-conditioning system is greater than or equal to the set time.

Step S340, if the continuous operation time of the whole multi-split system is longer than or equal to the set time, determining that the whole multi-split system is overloaded to operate.

Therefore, whether the complete machine of the multi-split air conditioning system runs in an overload mode or not is determined by sequentially judging the load of the external machine, the load of the internal machine and the running time of the multi-split air conditioning system, and the judgment on the overload running of the complete machine is accurate and reliable.

And step S230, if the whole multi-split system runs in an overload mode, determining whether the load of the multi-split system changes suddenly.

More optionally, the specific process of determining whether the load of the multi-split system is mutated in step S230 may further be described with reference to a schematic flow chart of an embodiment of determining whether the load of the multi-split system is mutated in the method shown in fig. 4, where the specific process may include: step S410 and step S420.

And step S410, determining whether the number of the running internal machines of the multi-split air-conditioning system is reduced and is greater than or equal to the set minimum running number.

Step S420, if the number of operating internal machines of the multi-split air-conditioning system is decreased and the number of operating internal machines is greater than or equal to the set minimum operating number, determining that the load of the multi-split air-conditioning system is suddenly changed, that is, determining that the multi-split air-conditioning system is in a load conversion stage. In addition, if the number of the running internal machines of the multi-split air conditioner system is not reduced or the number of the running internal machines is smaller than the set minimum running number, the opening degree of a refrigerant throttling device of the shutdown internal machine in the multi-split air conditioner system is stopped and controlled.

For example: because the air conditioner system is most easy to have the condition of sudden load change, the air conditioner system is under the condition that an internal machine is turned off and the whole air conditioner runs. By judging whether the closed indoor machine is used as a judgment condition for load conversion, the load is not changed more severely than the condition of shutdown in the running process of the whole machine. Such as: the five machines are 4 72 machines and 1 35 machines. All the internal machines are set to be in a maximum fan gear position, started and run at maximum load for heating for a period of time, 4 machines 72 are turned off at the moment, and the windshield of the 35 machine is adjusted to be in a low wind gear. At this time, the load of the whole machine can be judged to be suddenly changed.

For example: and (6) judging load conversion. The condition of severe load change of the air-conditioning multi-connected unit generally occurs when the indoor unit is turned on or turned off. When the condition of severe heating overload is met, when all the indoor units of the multi-connected air conditioning unit are started, a high windshield is set to stably run for more than 10MIN under the full load working condition (the indoor environment is 27 ℃, the outdoor environment is 24 ℃ and the indoor units are set to be 30 ℃), other indoor units are suddenly closed, and only one indoor unit with the minimum capacity is reserved and the lowest windshield is set to run. And determining whether the multi-connected air conditioner unit is in a load conversion state by judging whether the number of the running internal machines of the multi-connected air conditioner unit is reduced. For example: the air conditioning multi-connected unit drags N indoor units to heat and operate, any one or more of the N indoor units are closed, and at least one indoor unit needs to be kept to operate. And at the moment, the air conditioning multi-connected unit is judged to be in the load conversion stage.

Therefore, the sudden change of the load of the multi-split air-conditioning system is determined under the condition that the number of the running indoor units is reduced and is more than or equal to 1, so that the sudden change of the load is accurately and reliably determined.

And step S240, if the load of the multi-split air-conditioning system is suddenly changed, determining that the multi-split air-conditioning system is in a load conversion stage.

Therefore, under the condition that the whole multi-split system runs in an overload mode in the heating mode, if the load of the multi-split system changes suddenly, the multi-split system is determined to be in the load conversion stage, and the determination of the load conversion stage of the multi-split system is simple, convenient and reliable.

At step S120, if the multi-split air-conditioning system is in the load conversion stage, it is determined whether the coil temperature of the operating indoor unit in the multi-split air-conditioning system is greater than or equal to the upper limit of the set heating overload temperature range. In addition, if the multi-split air-conditioning system is not in the load conversion stage, the multi-split air-conditioning system is controlled to normally operate, and whether the multi-split air-conditioning system is in the load conversion stage or not is continuously determined.

Optionally, with reference to a flowchart of an embodiment of determining whether the coil temperature of the indoor unit operating in the multi-split air-conditioning system is greater than or equal to the upper limit of the set heating overload temperature range in the method of the present invention shown in fig. 5, a specific process of determining whether the coil temperature of the indoor unit operating in the multi-split air-conditioning system is greater than or equal to the upper limit of the set heating overload temperature range in step S120 may include: step S510 to step S530.

And step S510, determining the running internal machine with the highest coil temperature in all running internal machines in the multi-split air-conditioning system.

Step S520, determining the change rate of the coil temperature of the one running internal machine, determining the temperature range of the coil temperature of the one running internal machine in the set heating overload temperature range, and then determining whether the change rate of the coil temperature of the one running internal machine is greater than or equal to the upper limit of the set change rate range. Wherein, in the set heating overload temperature range, more than one temperature interval is divided according to the order of the temperature values. The upper limit of the range of the change rate may be set in correspondence with the upper limit of the range of the heating overload temperature.

Step S530, if the change rate of the coil temperature of the one running indoor unit is greater than or equal to the upper limit of the set change rate range, determining that the coil temperature of the running indoor unit in the multi-split air-conditioning system is greater than or equal to the upper limit of the set heating overload temperature range.

For example: and judging the temperature overload of the coil. In the load conversion stage of the air conditioning multi-connected unit, the temperature of a coil of an internal unit operated by the air conditioning multi-connected unit is read, and the relation between the temperature of the coil and a heating overload temperature threshold (such as the upper limit of a set heating overload temperature range) is judged.

Therefore, whether the coil temperature of the running inner machine in the multi-split air-conditioning system is larger than or equal to the upper limit of the set heating overload temperature range is determined by determining the relationship between the change rate of the coil temperature of the running inner machine with the highest coil temperature among all the running inner machines and the upper limit of the set change rate range, so that whether the coil temperature of the running inner machine is overheated or not is accurately and reliably determined.

In step S130, if the temperature of the coil of the operating indoor unit in the multi-split air-conditioning system is greater than or equal to the upper limit of the set heating overload temperature range, the opening of the refrigerant throttling device of the shutdown indoor unit in the multi-split air-conditioning system is controlled, so that part of the refrigerant that should flow to the operating indoor unit flows to the outdoor heat exchanger of the multi-split air-conditioning system after flowing to the shutdown indoor unit, that is, part of the high-temperature refrigerant that originally flows to the operating indoor unit flows to the shutdown indoor unit and then directly flows back to the outdoor heat exchanger, thereby reducing the temperature of the coil of the operating indoor unit in the multi-split air-conditioning system and avoiding the occurrence of heating overload protection shutdown due to the overhigh temperature of the. In addition, if the temperature of the coil of the running internal machine in the multi-split air conditioner system is smaller than the lower limit of the set heating overload temperature range, the multi-split air conditioner system is controlled to normally run, and whether the temperature of the coil of the running internal machine in the multi-split air conditioner system is larger than or equal to the upper limit of the set heating overload temperature range is continuously determined. The running indoor unit is an indoor unit running in a multi-split system. The shutdown indoor unit is an indoor unit which stops running in the multi-online system.

For example: when the heating load of the multi-connected air conditioning unit is converted, the temperature of a coil of the operating indoor unit is controlled by adjusting the opening of the shutdown indoor unit valve, so that shutdown is prevented from being protected due to overhigh temperature of the coil, and the reliability of the system and the experience of users are improved; the multi-split air conditioner can prevent the multi-split air conditioner from being protected from overheating by controlling the electronic expansion valve of the shutdown indoor unit, can solve the problem that high-voltage faults are easy to occur when the temperature of the coil is overheated during the heating operation of the multi-split air conditioner, can also solve the problem that other operating indoor units are easy to be protected from heating overload due to shutdown of part of the indoor units during the heating operation of the multi-split air conditioner, and improves the reliability of the system operation; meanwhile, the method can effectively solve the problems that the outer machine is easy to frost when the outer fan is stopped under heating overload, the outer fan is frequently started and stopped, and the comfort of the indoor machine is poor.

For example: when the load of the heating multi-split system is changed, the temperature of the coil pipe of the running indoor unit is suddenly increased, at the moment, the electronic expansion valve of the shutdown indoor unit is opened, so that a part of high-temperature refrigerant which originally flows to the running indoor unit rapidly flows to the shutdown indoor unit heat exchanger and then directly flows back to the outdoor heat exchanger, the temperature of the coil pipe of the running indoor unit can be rapidly reduced, and the problem that the running indoor unit is easy to overload to protect shutdown when the heating load is changed is effectively avoided. That is to say, when the heating load of the multi-connected air conditioner unit is switched (when part of the indoor units are shut down), part of the refrigerant is distributed to the side of the shutdown indoor unit by using the pipeline connecting the heat exchanger of the shut-down indoor unit and the compressor, so that the refrigerant circulation of the running indoor unit is quickly reduced in a short time, the effect of reducing the temperature of the inner pipe of the running indoor unit is achieved, and the risk of heat overload protection shutdown of the running indoor unit is reduced. Therefore, aiming at the phenomenon that the heating overload protection is shut down easily during the load conversion of the multi-split air conditioner in the heating mode and under the overload working condition, the existing internal and external machine refrigerant channel is utilized without adding an additional internal and external machine refrigerant connecting pipeline.

Therefore, under the condition that the temperature of the coil pipe of the indoor unit running in the heating mode of the multi-split air-conditioning system is determined to be larger than or equal to the upper limit of the heating overload temperature range, the opening degree of the refrigerant throttling device of the indoor unit running in the multi-split air-conditioning system is controlled, the temperature of the coil pipe of the indoor unit running in the multi-split air-conditioning system is reduced, the phenomenon that the heating overload protection is stopped due to the fact that the temperature of the coil pipe of the indoor unit running in the multi-split air-conditioning system is too high is avoided, the running reliability of the multi-split air-conditioning system.

Optionally, the controlling the opening degree of the refrigerant throttling device of the shutdown internal machine in the multi-split air conditioning system in step S130 may include: and determining the current change rate interval of the change rate of the coil temperature of the one running internal machine within the set change rate range, and/or determining the current temperature interval of the coil temperature of the one running internal machine within the set heating overload temperature range. And according to the current change rate interval and/or the current temperature interval, the current opening degree of a refrigerant throttling device of the shutdown internal machine in the multi-split system is adjusted to be a first opening degree and/or a second opening degree corresponding to the current change rate interval and/or the current temperature interval. That is to say, the process of controlling the opening degree of the refrigerant throttling device of the shutdown internal machine in the multi-split air-conditioning system may include a process of controlling the opening degree of the refrigerant throttling device of the shutdown internal machine according to the temperature of the coil pipe, and may also include a process of controlling the opening degree of the refrigerant throttling device of the shutdown internal machine according to the change rate of the temperature of the coil pipe, which may be specifically described in the following description.

For example: and controlling the opening of an electronic expansion valve of the indoor unit by load conversion shutdown.

For example: finding the indoor unit i with the highest coil pipe temperature for operating the indoor unit; calculating the change rate f of the highest coil temperature rise and the heating overload temperature threshold interval to which the coil temperature belongs; and comprehensively judging the opening of the electronic expansion valve of the shutdown indoor unit according to the change rate f and the temperature of the T coil. Such as: and controlling the opening of an electronic expansion valve of the indoor unit which stops running according to the calculated temperature change rate of the coil pipe and the overload temperature threshold interval, so that a part of refrigerant flows into the stopped indoor heat exchanger, and the refrigerant is reduced from flowing through the indoor heat exchanger of the running indoor unit.

The first control process: and controlling the opening of a refrigerant throttling device of the shutdown internal machine according to the temperature of the coil pipe.

The following further describes a specific process of controlling the opening degree of the refrigerant throttling device of the shutdown internal machine according to the temperature of the coil, with reference to a flow diagram of an embodiment of controlling the opening degree of the refrigerant throttling device of the shutdown internal machine according to the temperature of the coil in the method of the present invention shown in fig. 6, and the specific process may include: step S610 to step S630.

And step S610, determining the change rate of the coil temperature of the running internal machine, and determining the current change rate interval of the change rate of the coil temperature of the running internal machine within the set change rate range. In the set change rate range, more than one change rate interval is divided according to the size sequence of the change rate.

Step S620 is to determine, according to a first set relationship between a set change rate section and a set opening degree, a set opening degree corresponding to a set change rate section that is the same as the current change rate section in the first set relationship, and the set opening degree is a first opening degree to which the refrigerant throttling device corresponding to the current change rate section needs to be adjusted.

And step S630, the current opening degree of a refrigerant throttling device of the shutdown indoor unit in the multi-split system is adjusted to be the first opening degree.

For example: after the load of the whole machine is suddenly changed, the quantity of the sudden change can be judged according to the temperature of the coil pipe of the running internal machine. And controlling the opening of an electronic expansion valve of the indoor unit which stops running through the relationship between the temperature of the coil pipe and the heating overload temperature threshold value, so that a part of refrigerant flows into the stopped indoor heat exchanger and then directly enters the outdoor heat exchanger, and the refrigerant flowing through the indoor heat exchanger of the running indoor unit is reduced. Therefore, under the condition of sudden load change, the opening of the electronic expansion valve of the shutdown internal machine is controlled to realize the shunting of the refrigerant (instead of controlling the frequency of the compressor, the rotating speed of the outdoor fan, the rotating speed of the internal fan and the like), so that the stability and the balance of the system are realized, the reliability of the system is improved, and the comfort of a user is enhanced.

For example: controlling according to the highest coil temperature range: the temperature of the coil pipe is lower than 45 ℃ at 40 ℃, and the opening of an electronic expansion valve of the shutdown indoor unit is 50 p; the temperature of the coil pipe is lower than 45 ℃, and the opening of an electronic expansion valve of the shutdown indoor unit is 60 p; the temperature of the coil pipe is less than 55 ℃, and the opening of an electronic expansion valve of the shutdown indoor unit is 80 p; 55 ℃ is equal to the temperature of the coil pipe, and the opening of an electronic expansion valve of the shutdown indoor unit is equal to 100 p.

Therefore, the opening of the refrigerant throttling device of the shutdown internal machine is controlled according to the temperature of the coil pipe, the control mode is simple and convenient, and the control result is reliable.

The second control process: and controlling the opening of a refrigerant throttling device of the shutdown internal machine according to the change rate of the temperature of the coil pipe.

In the following, referring to a flow diagram of an embodiment of the method shown in fig. 7, which is used for controlling the opening degree of the refrigerant throttling device of the shutdown internal machine according to the change rate of the temperature of the coil, the specific process of controlling the opening degree of the refrigerant throttling device of the shutdown internal machine according to the change rate of the temperature of the coil is further described, and the specific process may include: step S710 to step S730.

And step S710, determining the current temperature interval of the coil temperature of the running indoor unit in the set heating overload temperature range.

And step S720, according to a second set relation between the set temperature interval and the set opening, determining the set opening corresponding to the same set temperature interval as the current temperature interval in the second set relation, and the second opening required to be adjusted by the refrigerant throttling device corresponding to the current temperature interval.

And step 730, adjusting the current opening degree of a refrigerant throttling device of the shutdown indoor unit in the multi-split system to the second opening degree.

For example: controlling according to the change rate: the faster the temperature of the coil rises and changes the rate f, the greater the opening of the electronic expansion valve of the shutdown indoor unit. f is more than or equal to 1 ℃/S, and the opening of the electronic expansion valve for shutdown is adjusted to be 100 p; f is less than 1 ℃/2S, and the opening of the electronic expansion valve for shutdown is adjusted to 80 p; f is less than 1 ℃/3S, and the opening of the electronic expansion valve for shutdown is adjusted to 60 p.

Therefore, the opening of the refrigerant throttling device of the shutdown internal machine is controlled according to the change rate of the temperature of the coil pipe, the control mode is simple and convenient, and the control result is reliable.

In an alternative embodiment, the method may further include: and exiting the process of controlling the opening of the refrigerant throttling device of the shutdown internal machine in the multi-split air conditioning system.

The following further describes a specific process of exiting and controlling the opening degree of the refrigerant throttling device of the shutdown internal machine in the multi-split air conditioning system, with reference to a flowchart of an embodiment of exiting and controlling the opening degree of the refrigerant throttling device of the shutdown internal machine in the multi-split air conditioning system in the method of the present invention shown in fig. 8, and the process may include: step S810 and step S820.

Step S810, after controlling the opening degree of a refrigerant throttling device of the shutdown indoor unit in the multi-split air-conditioning system, determining whether the temperature of a coil pipe of the running indoor unit in the multi-split air-conditioning system is reduced to be smaller than the lower limit of the set heating overload temperature range.

And step S810, if the temperature of the coil pipe of the running indoor unit in the multi-split air-conditioning system is reduced to be smaller than the lower limit of the set heating overload temperature range, stopping controlling the opening degree of a refrigerant throttling device of the shutdown indoor unit in the multi-split air-conditioning system. In addition, the temperature of the coil pipe of the running internal machine in the multi-split air conditioner system is not reduced to be smaller than the lower limit of the set heating overload temperature range, and the opening degree of the refrigerant throttling device of the shutdown internal machine in the multi-split air conditioner system is continuously controlled.

For example: and judging whether the opening of the electronic expansion valve for controlling the stop operation of the indoor unit is quitted or not according to the relationship between the temperature of the coil pipe and the heating overload temperature threshold.

Wherein, shut down the refrigerant throttling arrangement of interior machine, can include: an electronic expansion valve or a capillary tube.

For example: under the condition of not increasing hardware cost, the problem that the multi-connected unit of the air conditioner in high-load heating operation is easy to heat overload protection during load conversion is effectively solved, and the method can be widely applied to the field of control of the multi-connected unit air conditioner.

For example: in the overload of the multi-connected unit caused by the heating load conversion, the temperature of the coil pipe of the running indoor unit is reduced by adjusting the opening of the electronic expansion valve of the shutdown indoor unit. The opening control of the electronic expansion valve of the indoor unit for multi-split shutdown is to be a certain opening on the basis of the original shutdown opening, and the original opening may be 0P or the step number of other numerical values.

For example: and in the heating mode of the multi-connected air conditioner unit, as long as the condition of closing the indoor unit is concerned, the opening degree of all the stopped electronic expansion valves is increased according to the fixed opening degree.

Therefore, after the opening degree of the refrigerant throttling device of the shutdown inner machine in the multi-split system is controlled, the opening degree of the refrigerant throttling device of the shutdown inner machine in the multi-split system is quitted, the opening degree control of the refrigerant throttling device of the shutdown inner machine can be quitted after the temperature of the coil pipe of the operation inner machine in the heating mode is reduced, and the control is reliable and safe.

Through a large number of tests, the technical scheme of the embodiment is adopted, and all the electronic expansion valves for shutdown are opened according to a fixed opening degree as long as the condition of closing the indoor units is related to the operation of the heating mode of the multi-connected air conditioning unit, so that additional internal and external refrigerant connecting pipelines are not required to be added, the phenomenon of heating overload protection shutdown is avoided easily occurring under the overload working condition during the multi-connected air conditioning load conversion in the heating mode by using the existing internal and external refrigerant channels, and the operation reliability of the multi-connected air conditioning unit is improved.

According to an embodiment of the present invention, there is also provided a control apparatus of a multi-split system corresponding to the control method of the multi-split system. Referring to fig. 9, a schematic diagram of an embodiment of the apparatus of the present invention is shown. The control apparatus of the multi-split system may include: a determination unit 102 and a control unit 104.

In an alternative example, the determining unit 102 may be configured to determine whether the multi-split system is in a load conversion phase. The load conversion stage refers to a situation that a load suddenly changes when the multi-split air conditioning system operates, for example, the situation that the load suddenly changes when an internal unit is turned off when the multi-split air conditioning system operates in a heating mode. The specific function and processing of the determination unit 102 are referred to in step S110.

Optionally, the determining unit 102 determines whether the multiple online system is in a load conversion stage, which may include:

the determining unit 102 may be further configured to determine whether the multi-split air-conditioning system operates in a heating mode. The specific function and processing of the determination unit 102 are also referred to in step S210.

The determining unit 102 may be further configured to determine whether the entire multi-split air-conditioning system is in overload operation if the multi-split air-conditioning system operates in the heating mode. The specific function and processing of the determination unit 102 are also referred to in step S220.

More optionally, the determining unit 102 determines whether the entire multi-split system is running under overload, which may include:

the determining unit 102 may be further configured to determine whether an outdoor environment temperature of an environment to which the multi-split air conditioning system belongs is within a set outdoor temperature range. The specific function and processing of the determination unit 102 are also referred to in step S310.

The determining unit 102 may be further configured to determine whether a temperature difference between a set temperature of an operating indoor unit of the multi-split air-conditioning system and an indoor ambient temperature of an environment to which the multi-split air-conditioning system belongs is greater than or equal to a set temperature threshold value, if the outdoor ambient temperature of the environment to which the multi-split air-conditioning system belongs is within a set outdoor temperature range. The specific function and processing of the determination unit 102 are also referred to in step S320.

The determining unit 102 may be further configured to determine whether a continuous operation duration of the entire multi-split air-conditioning system is greater than or equal to a set duration if a temperature difference between a set temperature of an operating internal unit of the multi-split air-conditioning system and an indoor ambient temperature of an environment to which the multi-split air-conditioning system belongs is greater than or equal to a set temperature threshold. The specific function and processing of the determination unit 102 are also referred to in step S330.

The determining unit 102 may be further configured to determine that the complete multi-split air-conditioning system is overloaded and operates if the continuous operation time of the complete multi-split air-conditioning system is greater than or equal to the set time. The specific function and processing of the determination unit 102 are also referred to in step S340.

The determining unit 102 may be further configured to determine whether the load of the multi-split air-conditioning system changes suddenly if the entire multi-split air-conditioning system runs in an overload manner. The specific function and processing of the determination unit 102 are also referred to in step S230.

More optionally, the determining unit 102 determines whether the load of the multi-split system has a sudden change, which may include:

the determining unit 102 may be further configured to determine whether the number of running internal machines of the multi-split air-conditioning system is reduced, and the number of running internal machines is greater than or equal to the set minimum running number. The specific function and processing of the determination unit 102 are also referred to in step S410.

The determining unit 102 may be further specifically configured to determine that the load of the multi-split air-conditioning system changes suddenly, that is, determine that the multi-split air-conditioning system is in a load conversion stage, if the number of the operating internal machines of the multi-split air-conditioning system is reduced and is greater than or equal to the set minimum operating number. In addition, if the number of the running internal machines of the multi-split air conditioner system is not reduced or the number of the running internal machines is smaller than the set minimum running number, the opening degree of a refrigerant throttling device of the shutdown internal machine in the multi-split air conditioner system is stopped and controlled. The specific function and processing of the determination unit 102 are also referred to step S420.

The determining unit 102 may be further specifically configured to determine that the multi-split air-conditioning system is in a load conversion stage if the load of the multi-split air-conditioning system changes suddenly. The specific function and processing of the determination unit 102 are also referred to step S240.

In an optional example, the determining unit 102 may be further configured to determine whether a coil temperature of an operating indoor unit in the multi-split air-conditioning system is greater than or equal to an upper limit of a set heating overload temperature range if the multi-split air-conditioning system is in the load conversion stage. In addition, if the multi-split air-conditioning system is not in the load conversion stage, the multi-split air-conditioning system is controlled to normally operate, and whether the multi-split air-conditioning system is in the load conversion stage or not is continuously determined. The specific function and processing of the determination unit 102 are also referred to in step S120.

10. The apparatus according to claim 7, wherein the determining unit 102 determines whether the coil temperature of the indoor unit operating in the multi-split air conditioning system is greater than or equal to the upper limit of the set heating overload temperature range, and may include:

the determining unit 102 may be further specifically configured to determine one of all operating internal machines in the multi-split air conditioning system, where the coil temperature is the highest. The specific function and processing of the determination unit 102 are also referred to in step S510.

The determining unit 102 may be further configured to determine a change rate of the coil temperature of the one operating indoor unit, determine a temperature range of the coil temperature of the one operating indoor unit in the set heating overload temperature range, and then determine whether the change rate of the coil temperature of the one operating indoor unit is greater than or equal to an upper limit of the set change rate range. Wherein, in the set heating overload temperature range, more than one temperature interval is divided according to the order of the temperature values. The upper limit of the range of the change rate may be set in correspondence with the upper limit of the range of the heating overload temperature. The specific function and processing of the determination unit 102 are also referred to in step S520.

The determining unit 102 may be further specifically configured to determine that the coil temperature of the operating indoor unit in the multi-split air-conditioning system is greater than or equal to the upper limit of the set heating overload temperature range if the change rate of the coil temperature of the operating indoor unit is greater than or equal to the upper limit of the set change rate range. The specific function and processing of the determination unit 102 are also referred to in step S530. For example: and judging the temperature overload of the coil. In the load conversion stage of the air conditioning multi-connected unit, the temperature of a coil of an internal unit operated by the air conditioning multi-connected unit is read, and the relation between the temperature of the coil and a heating overload temperature threshold (such as the upper limit of a set heating overload temperature range) is judged.

In an optional example, the control unit 104 may be configured to control an opening degree of a refrigerant throttling device of the shutdown indoor unit in the multi-split air-conditioning system, if the temperature of the coil pipe of the operation indoor unit in the multi-split air-conditioning system is greater than or equal to an upper limit of a set heating overload temperature range, so that part of the refrigerant that should flow to the operation indoor unit becomes the refrigerant that flows to the shutdown indoor unit and then flows back to the outdoor heat exchanger of the multi-split air-conditioning system, that is, part of the high-temperature refrigerant that originally flows to the operation indoor unit flows to the shutdown indoor unit and then directly flows back to the outdoor heat exchanger, thereby reducing the temperature of the coil pipe of the operation indoor unit in the multi-split air-conditioning system and avoiding the occurrence of heating overload protection. In addition, if the temperature of the coil of the running internal machine in the multi-split air conditioner system is smaller than the lower limit of the set heating overload temperature range, the multi-split air conditioner system is controlled to normally run, and whether the temperature of the coil of the running internal machine in the multi-split air conditioner system is larger than or equal to the upper limit of the set heating overload temperature range is continuously determined. The running indoor unit is an indoor unit running in a multi-split system. The shutdown indoor unit is an indoor unit which stops running in the multi-online system. The specific function and processing of the control unit 104 are shown in step S130.

Optionally, the controlling unit 104 controls an opening degree of a refrigerant throttling device of a shutdown internal machine in the multi-split air conditioning system, and may include: and determining the current change rate interval of the change rate of the coil temperature of the one running internal machine within the set change rate range, and/or determining the current temperature interval of the coil temperature of the one running internal machine within the set heating overload temperature range. And according to the current change rate interval and/or the current temperature interval, the current opening degree of a refrigerant throttling device of the shutdown internal machine in the multi-split system is adjusted to be a first opening degree and/or a second opening degree corresponding to the current change rate interval and/or the current temperature interval. That is to say, the process of controlling the opening degree of the refrigerant throttling device of the shutdown internal machine in the multi-split air-conditioning system may include a process of controlling the opening degree of the refrigerant throttling device of the shutdown internal machine according to the temperature of the coil pipe, and may also include a process of controlling the opening degree of the refrigerant throttling device of the shutdown internal machine according to the change rate of the temperature of the coil pipe, which may be specifically described in the following description.

The control unit 104 may be further configured to determine a change rate of the coil temperature of the one operating indoor unit, and determine a current change rate interval of the change rate of the coil temperature of the one operating indoor unit within a set change rate range. In the set change rate range, more than one change rate interval is divided according to the size sequence of the change rate. The specific functions and processes of the control unit 104 are also referred to in step S610.

The control unit 104 may be further configured to determine, according to a first set relationship between a set change rate section and a set opening degree, a set opening degree corresponding to a set change rate section that is the same as the current change rate section in the first set relationship, and adjust the set opening degree to a first opening degree required by the refrigerant throttling device corresponding to the current change rate section. And the current opening degree of a refrigerant throttling device of the shutdown internal machine in the multi-online system is adjusted to the first opening degree. The specific functions and processes of the control unit 104 are also referred to in step S620.

The control unit 104 may be further configured to determine a current temperature range of the coil temperature of the one operating indoor unit in the set heating overload temperature range. The specific functions and processes of the control unit 104 are also referred to in step S710.

The control unit 104 may be further configured to determine, according to a second set relationship between the set temperature interval and the set opening degree, a set opening degree corresponding to a set temperature interval that is the same as the current temperature interval in the second set relationship, and adjust the set opening degree to a second opening degree required by the refrigerant throttling device corresponding to the current temperature interval. And the current opening degree of a refrigerant throttling device of the shutdown internal machine in the multi-online system is adjusted to the second opening degree. The specific functions and processes of the control unit 104 are also referred to in step S720.

The determining unit 102 may be further configured to determine whether the temperature of a coil of the indoor unit in the multi-split air conditioning system has been reduced to be less than a lower limit of the set heating overload temperature range after controlling the opening degree of the refrigerant throttling device of the indoor unit in the multi-split air conditioning system. The specific function and processing of the determination unit 102 are also referred to in step S810.

The control unit 104 may be further configured to stop controlling the opening of the refrigerant throttling device of the shutdown indoor unit in the multi-split air-conditioning system if the temperature of the coil pipe of the running indoor unit in the multi-split air-conditioning system is reduced to be less than the lower limit of the set heating overload temperature range. In addition, the temperature of the coil pipe of the running internal machine in the multi-split air conditioner system is not reduced to be smaller than the lower limit of the set heating overload temperature range, and the opening degree of the refrigerant throttling device of the shutdown internal machine in the multi-split air conditioner system is continuously controlled. The specific function and processing of the control unit 104 are also referred to in step S820.

Since the processes and functions implemented by the apparatus of this embodiment substantially correspond to the embodiments, principles and examples of the method shown in fig. 1 to 8, the description of this embodiment is not detailed, and reference may be made to the related descriptions in the foregoing embodiments, which are not repeated herein.

Through a large number of tests, the technical scheme of the invention is adopted to reduce the temperature of the coil pipe of the running indoor unit by adjusting the opening of the electronic expansion valve of the shutdown indoor unit, and improve the running reliability and user experience of the air conditioner.

According to an embodiment of the present invention, there is also provided a multi-split system corresponding to a control apparatus of the multi-split system. The multi-split system may include: the control device of the multi-split system is described above.

In order to control the coil temperature of the indoor heat exchanger not to be too high, the rotating speed of the outdoor fan is reduced or stopped by increasing or maintaining the rotating speed of the indoor fan, and the rotating speed of the compressor is reduced or stopped until the coil temperature of the indoor fan is reduced to be within a reliable operation range.

For the multi-connected unit, when the heating operation in part of the multi-connected unit causes the compressor to be subjected to frequency reduction or shutdown due to overhigh temperature of the coil, the fan is subjected to speed reduction or shutdown, and some problems exist. For example: firstly, the heating effect of other running internal machines is reduced, and the comfort is influenced; secondly, the noise problem is caused by frequent starting and stopping of the outer fan and the compressor or the rise and fall of the rotating speed; thirdly, the outdoor unit is easy to frost on the heat exchanger because the outdoor unit is stopped for too long or the rotating speed is too low.

In addition, when the load of the multi-connected unit in high-load heating operation is switched (part of the indoor units are turned off), the refrigerant which originally flows to the shutdown indoor unit can quickly flow to the running indoor unit, so that the temperature of a coil pipe for running the indoor unit is rapidly increased, and the problem of shutdown protection due to heating overload is caused.

In an optional embodiment, the invention provides a control scheme for preventing the multiple air-conditioner multiple on-line overheating protection, which can enable the multiple on-line to prevent the multiple air-conditioner multiple on-line overheating protection by controlling the electronic expansion valve of the shutdown indoor unit.

Specifically, the scheme of the invention provides a control method and a control device for multi-connected air conditioner overheating protection, which can solve the problem that high-voltage faults are easily caused by overheating of the coil pipe during the heating operation of the multi-connected air conditioner, can also solve the problem that other operating indoor units are easily subjected to heating overload protection due to shutdown of part of the indoor units during the heating operation of the multi-connected air conditioner, and improve the reliability of the operation of the system; meanwhile, the method can effectively solve the problems that the outer machine is easy to frost when the outer fan is stopped under heating overload, the outer fan is frequently started and stopped, and the comfort of the indoor machine is poor.

In an optional example, the scheme of the invention provides a control method and a control device for multi-connected air conditioner overheating protection, so as to solve the problem that when the load of a multi-connected air conditioner unit in high-load heating operation is converted, an operating indoor unit is easy to heat, overload, protect and shut down.

According to the scheme of the invention, when the load of the heating multi-split system is converted, the temperature of the coil pipe of the running indoor unit is suddenly increased, and at the moment, the electronic expansion valve of the shutdown indoor unit is opened, so that a part of high-temperature refrigerant originally flowing to the running indoor unit rapidly flows to the shutdown indoor unit heat exchanger and then directly flows back to the outdoor heat exchanger, the temperature of the coil pipe of the running indoor unit can be rapidly reduced, and the problem that the running indoor unit is easy to overload to protect shutdown when the heating load is converted is effectively avoided.

That is to say, when the heating load of the multi-connected air conditioner unit is switched (when part of the indoor units are shut down), part of the refrigerant is distributed to the side of the shutdown indoor unit by using the pipeline connecting the heat exchanger of the shut-down indoor unit and the compressor, so that the refrigerant circulation of the running indoor unit is quickly reduced in a short time, the effect of reducing the temperature of the inner pipe of the running indoor unit is achieved, and the risk of heat overload protection shutdown of the running indoor unit is reduced. Therefore, aiming at the phenomenon that the heating overload protection is shut down easily under the overload working condition during the load conversion of the multi-split air conditioner in the heating mode, the scheme of the invention can solve the problem by utilizing the existing internal and external refrigerant passage without adding an additional internal and external refrigerant connecting pipeline. If the opening of the electronic expansion valve of the shut-down internal unit is adjusted to be large when the internal unit is in heating operation, the aim of the invention can be achieved.

Specifically, the following steps may be included:

step 1, judging whether an operation mode of an air conditioning multi-connected unit is a heating mode operation; if yes, executing step 2; otherwise, continue to wait at step 1.

Step 2, judging whether the number of the running internal machines of the air conditioning multi-connected unit is reduced, namely whether the internal machines are shut down; if yes, executing step 3; otherwise, continue to wait at step 2.

In step 2, the air conditioner system is most likely to have sudden load change, which is the case when the internal machine is turned off and the whole machine is running. The scheme of the invention judges whether the closed indoor unit is used as a judgment condition for load conversion or not. The load is not changed violently compared with the shutdown condition in the running process of the whole machine.

For example: the five machines are 4 72 machines and 1 35 machines. All the internal machines are set to be in a maximum fan gear position, started and run at maximum load for heating for a period of time, 4 machines 72 are turned off at the moment, and the windshield of the 35 machine is adjusted to be in a low wind gear. At this time, the load of the whole machine can be judged to be suddenly changed.

And 3, reading the temperature of a coil of an indoor unit operated by the multi-connected air conditioning unit, and judging the relationship between the temperature of the coil and a heating overload temperature threshold value.

In step 3, after the load of the whole machine suddenly changes, the quantity of sudden change can be judged according to the temperature of the coil pipe of the running internal machine.

And 4, controlling the opening of an electronic expansion valve of the indoor unit which stops running through the relationship between the temperature of the coil pipe and the heating overload temperature threshold value, so that a part of refrigerant flows into the stopped indoor heat exchanger and then directly enters the outdoor heat exchanger, and reducing the refrigerant flowing through the indoor heat exchanger which runs the indoor unit.

In step 4, under the condition of sudden load change, the opening of the electronic expansion valve of the shutdown internal machine is controlled to realize the distribution of the refrigerant (instead of controlling the frequency of the compressor, the rotating speed of the outdoor fan, the rotating speed of the internal fan and the like), so that the stability and balance of the system are realized, the reliability of the system is improved, and the comfort of users is enhanced.

And 5, judging whether the opening of the electronic expansion valve for controlling the stop operation of the indoor unit is quitted or not according to the relationship between the temperature of the coil pipe and the heating overload temperature threshold.

Therefore, compared with the traditional method of adding an additional connecting pipeline, the method and the device for controlling the multi-connected air conditioner overheating protection effectively solve the problem that the multi-connected air conditioner unit in high-load heating operation is easy to heat and overload and protect when the load of the multi-connected air conditioner unit is converted under the condition of not increasing the hardware cost, and can be widely applied to the field of control of the multi-connected air conditioner unit.

In an alternative embodiment, reference may be made to the examples shown in fig. 10 to 16 to illustrate a specific implementation process of the scheme of the present invention.

According to the scheme provided by the invention, the temperature of the coil pipe of the operating indoor unit is controlled by adjusting the opening of the shutdown indoor unit valve when the heating load of the multi-connected air conditioning unit is converted, the shutdown is prevented from being protected due to overhigh coil pipe temperature, and the reliability of the system and the experience of users are improved.

Specific embodiments may be as follows:

the first step is as follows: and confirming the mode. And judging whether the operation mode of the multi-connected air conditioning unit is the heating mode operation.

The second step is as follows: and (6) judging load conversion. The condition of severe load change of the air-conditioning multi-connected unit generally occurs when the indoor unit is turned on or turned off. When the condition of severe heating overload is met, when all the indoor units of the multi-connected air conditioning unit are started, a high windshield is set to stably run for more than 10MIN under the full load working condition (the indoor environment is 27 ℃, the outdoor environment is 24 ℃ and the indoor units are set to be 30 ℃), other indoor units are suddenly closed, and only one indoor unit with the minimum capacity is reserved and the lowest windshield is set to run. And determining whether the multi-connected air conditioner unit is in a load conversion state by judging whether the number of the running internal machines of the multi-connected air conditioner unit is reduced. For example: the air conditioning multi-connected unit drags N indoor units to heat and operate, any one or more of the N indoor units are closed, and at least one indoor unit needs to be kept to operate. And at the moment, the air conditioning multi-connected unit is judged to be in the load conversion stage.

The third step: and judging the temperature overload of the coil. And in the load conversion stage of the air conditioning multi-connected unit, reading the temperature of a coil of an indoor unit operated by the air conditioning multi-connected unit, and judging the relationship between the temperature of the coil and a heating overload temperature threshold value. For example, the following judgment is specifically made:

1) and finding the indoor unit i with the highest coil temperature for operating the indoor unit.

2) And calculating the change rate f of the highest coil temperature rise and the heating overload temperature threshold interval to which the coil temperature belongs.

The fourth step: and controlling the opening of an electronic expansion valve of the indoor unit by load conversion shutdown. And C, controlling the opening of an electronic expansion valve of the indoor unit which stops running according to the temperature change rate of the coil pipe calculated in the step three and the overload temperature threshold interval, so that a part of refrigerant flows into the stopped indoor heat exchanger, and the refrigerant is reduced from flowing through the indoor heat exchanger of the running indoor unit. For example, it can be controlled as follows:

1) controlling according to the change rate: the faster the temperature of the coil rises and changes the rate f, the greater the opening of the electronic expansion valve of the shutdown indoor unit. f is more than or equal to 1 ℃/S, and the opening of the electronic expansion valve for shutdown is adjusted to be 100 p; f is less than 1 ℃/2S, and the opening of the electronic expansion valve for shutdown is adjusted to 80 p; f is less than 1 ℃/3S, and the opening of the electronic expansion valve for shutdown is adjusted to 60 p.

2) Controlling according to the highest coil temperature range: the temperature of the coil pipe is lower than 45 ℃ at 40 ℃, and the opening of an electronic expansion valve of the shutdown indoor unit is 50 p; the temperature of the coil pipe is lower than 45 ℃, and the opening of an electronic expansion valve of the shutdown indoor unit is 60 p; the temperature of the coil pipe is less than 55 ℃, and the opening of an electronic expansion valve of the shutdown indoor unit is 80 p; 55 ℃ is equal to the temperature of the coil pipe, and the opening of an electronic expansion valve of the shutdown indoor unit is equal to 100 p.

3) And comprehensively judging the opening of the electronic expansion valve of the shutdown indoor unit according to the change rate f and the temperature of the T coil.

The fifth step: and exiting load conversion shutdown of the indoor unit by opening control of the electronic expansion valve. And judging whether the opening of the electronic expansion valve for controlling the stop operation of the indoor unit is quitted or not according to the third step.

For example: and when the change rate f is equal to 0, exiting the opening control of the electronic expansion valve of the load conversion shutdown indoor unit. T40 ℃ and the maximum coil temperature, and the opening control of the electronic expansion valve of the indoor unit of the load conversion shutdown machine is quitted.

It should be noted that, in an overload of the multi-connected unit caused by the heating load conversion, as long as the control method for reducing the temperature of the coil of the operating indoor unit by adjusting the opening of the electronic expansion valve of the stopped indoor unit is involved, the control method is within the protection scope of the scheme of the present invention.

The opening control of the electronic expansion valve of the indoor unit for the multi-split shutdown is to be a certain opening on the basis of the original shutdown opening. The original opening may be 0P or other number of steps.

In addition, in order to simplify the control scheme, the heating mode of the multi-connected air conditioner unit is operated by opening all the electronic expansion valves for shutdown according to a fixed opening as long as the condition of closing the indoor units is concerned.

Since the processing and functions implemented by the multi-split system of the present embodiment substantially correspond to the embodiment, the principle and the example of the apparatus shown in fig. 9, the description of the present embodiment is not detailed, and reference may be made to the related description in the foregoing embodiments, which is not repeated herein.

Through a large number of tests, the technical scheme of the invention is adopted, and the opening of the electronic expansion valve of the indoor unit for multi-online shutdown is controlled to be a certain opening on the basis of the original shutdown opening, so that the reliability and the stability of overheat protection are improved.

According to an embodiment of the present invention, there is also provided a storage medium corresponding to a control method of a multi-split system. The storage medium may include: the storage medium has stored therein a plurality of instructions; the instructions are used for loading and executing the control method of the multi-split system by the processor.

Since the processing and functions implemented by the storage medium of this embodiment substantially correspond to the embodiments, principles, and examples of the methods shown in fig. 1 to 8, the description of this embodiment is not detailed, and reference may be made to the related descriptions in the foregoing embodiments, which are not described herein again.

Through a large number of tests, the technical scheme of the invention is adopted, when the heating load of the multi-connected air conditioner unit is converted, a part of refrigerant is distributed to the side of the shutdown indoor unit by utilizing a pipeline connected with the heat exchanger and the compressor of the shutdown indoor unit, so that the refrigerant circulation of the running indoor unit is quickly reduced in a short time, the effect of reducing the temperature of the inner pipe of the running indoor unit is achieved, the risk of shutdown of the running indoor unit under the condition of heat overload protection is reduced, the running reliability is good, and the user comfort level experience is good.

According to an embodiment of the present invention, there is also provided a multi-split system corresponding to a control method of the multi-split system. The multi-split system may include: a processor for executing a plurality of instructions; a memory to store a plurality of instructions; the instructions are stored in the memory, and loaded by the processor and execute the control method of the multi-split system.

Since the processing and functions implemented by the multi-split system of the present embodiment substantially correspond to the embodiments, principles and examples of the methods shown in fig. 1 to fig. 8, reference may be made to the related descriptions in the foregoing embodiments for details which are not described in the description of the present embodiment, and thus are not described herein again.

Through a large number of tests, the technical scheme of the invention is adopted, when the load of the heating multi-split system is converted, the temperature of the coil pipe of the running indoor unit is suddenly increased, at the moment, the electronic expansion valve of the shutdown indoor unit is opened, so that a part of high-temperature refrigerant originally flowing to the indoor unit during running rapidly flows to the heat exchanger of the shutdown indoor unit and then directly flows back to the outdoor heat exchanger, the temperature of the coil pipe of the running indoor unit can be rapidly reduced, the problem that the running indoor unit is easy to overload to protect shutdown during the conversion of the heating load is effectively avoided, and the running reliability.

In summary, it is readily understood by those skilled in the art that the advantageous modes described above can be freely combined and superimposed without conflict.

The above description is only an example of the present invention, and is not intended to limit the present invention, and it is obvious to those skilled in the art that various modifications and variations can be made in the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A method for controlling a multi-split system, comprising:

determining whether the multi-split system is in a load conversion stage;

if the multi-split system is in the load conversion stage, determining whether the temperature of a coil of an operating indoor unit in the multi-split system is greater than or equal to the upper limit of the set heating overload temperature range;

and if the temperature of the coil pipe of the running indoor unit in the multi-split air-conditioning system is greater than or equal to the upper limit of the set heating overload temperature range, controlling the opening of a refrigerant throttling device of the shutdown indoor unit in the multi-split air-conditioning system, so that part of the refrigerant which needs to flow to the running indoor unit is changed into the refrigerant which flows to the shutdown indoor unit and then flows back to the outdoor heat exchanger of the multi-split air-conditioning system.

2. The method of claim 1, wherein determining whether the multi-split air conditioning system is in a load transfer phase comprises:

determining whether the multi-split system is operated in a heating mode;

if the multi-split system operates in the heating mode, determining whether the whole multi-split system operates in an overload mode;

if the whole multi-split system runs in an overload mode, determining whether the load of the multi-split system changes suddenly;

and if the load of the multi-split system is suddenly changed, determining that the multi-split system is in a load conversion stage.

3. The method of claim 2, wherein,

determining whether the whole machine of the multi-split system runs in an overload mode or not, wherein the determining step comprises the following steps:

determining whether the outdoor environment temperature of the environment to which the multi-split air-conditioning system belongs is within a set outdoor temperature range;

if the outdoor environment temperature of the environment to which the multi-split air-conditioning system belongs is within the set outdoor temperature range, determining whether the set temperature of the running indoor unit of the multi-split air-conditioning system and the temperature difference value of the indoor environment temperature of the environment to which the multi-split air-conditioning system belongs are larger than or equal to a set temperature threshold value;

if the temperature difference between the set temperature of the running internal machine of the multi-split air-conditioning system and the indoor environment temperature of the environment to which the multi-split air-conditioning system belongs is greater than or equal to the set temperature threshold, determining whether the continuous running time of the whole multi-split air-conditioning system is greater than or equal to the set time;

if the continuous operation time of the complete machine of the multi-split system is longer than or equal to the set time, determining the complete machine of the multi-split system to operate in an overload mode;

and/or the presence of a gas in the gas,

determining whether the load of the multi-split system is suddenly changed, comprising the following steps:

determining whether the number of running internal machines of the multi-split air-conditioning system is reduced and is greater than or equal to the set minimum running number;

and if the number of the running internal machines of the multi-split air-conditioning system is reduced and is greater than or equal to the set minimum running number, determining that the load of the multi-split air-conditioning system is suddenly changed.

4. The method of claim 1, wherein determining whether a coil temperature of an operating indoor unit in the multi-split air conditioning system is greater than or equal to an upper limit of a set heating overload temperature range comprises:

determining one running internal machine with the highest coil pipe temperature in all running internal machines in the multi-split air-conditioning system;

determining whether the rate of change of the coil temperature of the one operating machine is greater than or equal to the upper limit of the set rate of change range;

and if the change rate of the coil temperature of the one running indoor unit is greater than or equal to the upper limit of the set change rate range, determining that the coil temperature of the running indoor unit in the multi-split air-conditioning system is greater than or equal to the upper limit of the set heating overload temperature range.

5. The method as claimed in claim 1, wherein controlling the opening degree of a refrigerant throttling device of a shutdown indoor unit in the multi-split air conditioning system comprises:

determining the current change rate interval of the change rate of the coil temperature of the running internal machine within the set change rate range;

according to a first set relation between a set change rate section and a set opening degree, determining the set opening degree corresponding to the set change rate section which is the same as the current change rate section in the first set relation, and the set opening degree is a first opening degree required to be increased by a refrigerant throttling device corresponding to the current change rate section;

the current opening degree of a refrigerant throttling device of a shutdown internal machine in the multi-online system is adjusted to be the first opening degree;

and/or the presence of a gas in the gas,

determining the current temperature interval of the coil temperature of the running internal machine in the set heating overload temperature range;

according to a second set relationship between the set temperature interval and the set opening degree, determining the set opening degree corresponding to the same set temperature interval as the current temperature interval in the second set relationship, and the set opening degree is the second opening degree required to be increased by the refrigerant throttling device corresponding to the current temperature interval;

and the current opening degree of a refrigerant throttling device of the shutdown internal machine in the multi-online system is adjusted to the second opening degree.

6. The method of any one of claims 1 to 5, further comprising:

after controlling the opening degree of a refrigerant throttling device of a shutdown indoor unit in the multi-split air conditioning system, determining whether the temperature of a coil pipe of the running indoor unit in the multi-split air conditioning system is reduced to be smaller than the lower limit of a set heating overload temperature range;

if the temperature of a coil pipe of an operating indoor unit in the multi-split air-conditioning system is reduced to be smaller than the lower limit of the set heating overload temperature range, stopping controlling the opening of a refrigerant throttling device of a shutdown indoor unit in the multi-split air-conditioning system;

wherein, shut down the refrigerant throttling arrangement of interior machine, include: an electronic expansion valve or a capillary tube.

7. A control device of a multi-split system, comprising:

the determining unit is used for determining whether the multi-split system is in a load conversion stage;

the determining unit is further used for determining whether the temperature of a coil of an operating indoor unit in the multi-split system is greater than or equal to the upper limit of the set heating overload temperature range or not if the multi-split system is in the load conversion stage;

and the control unit is used for controlling the opening degree of a refrigerant throttling device of the shutdown indoor unit in the multi-split system if the temperature of the coil pipe of the running indoor unit in the multi-split system is greater than or equal to the upper limit of the set heating overload temperature range, so that part of the refrigerant which should flow to the running indoor unit is changed into the refrigerant which flows to the shutdown indoor unit and then flows back to the outdoor heat exchanger of the multi-split system.

8. The apparatus of claim 7, wherein the determining unit determines whether the multi-split air conditioning system is in a load transfer phase, comprising:

determining whether the multi-split system is operated in a heating mode;

9. The apparatus of claim 8, wherein,

the determining unit determines whether the whole multi-split system runs in an overload mode or not, and comprises the following steps:

and/or the presence of a gas in the gas,

the determining unit determines whether the load of the multi-split air conditioning system is suddenly changed, and comprises the following steps:

10. The apparatus of claim 7, wherein the determining unit determines whether the coil temperature of the indoor unit operating in the multi-split air conditioning system is greater than or equal to the upper limit of the set heating overload temperature range, and comprises:

11. The device as claimed in claim 7, wherein the control unit controls the opening degree of a refrigerant throttling device of the shutdown internal machine in the multi-split air conditioning system, and comprises:

and/or the presence of a gas in the gas,

12. The apparatus of any one of claims 7 to 11, further comprising:

the determining unit is further used for determining whether the temperature of a coil pipe of the running internal machine in the multi-split air-conditioning system is reduced to be smaller than the lower limit of the set heating overload temperature range after controlling the opening degree of a refrigerant throttling device of the shutdown internal machine in the multi-split air-conditioning system;

the control unit is also used for stopping controlling the opening degree of a refrigerant throttling device of the shutdown indoor unit in the multi-split air-conditioning system if the temperature of a coil pipe of the running indoor unit in the multi-split air-conditioning system is reduced to be smaller than the lower limit of the set heating overload temperature range;

13. A multiple on-line system, comprising: a control device of a multi-split system as defined in any one of claims 7 to 12;

alternatively, the first and second electrodes may be,

the method comprises the following steps:

a processor for executing a plurality of instructions;

a memory to store a plurality of instructions;

wherein the plurality of instructions are stored by the memory, and loaded and executed by the processor to perform the method of controlling a multi-split system as set forth in any one of claims 1 to 6.

14. A storage medium having a plurality of instructions stored therein; the plurality of instructions for loading and executing the control method of the multi-online system as recited in any one of claims 1 to 6 by a processor.