CN107965853A - The outdoor unit and control method of three control multi-line systems - Google Patents

Abstract

The invention discloses an outdoor unit and a control method of a three-pipe multi-connection system. The outdoor unit is provided with a high-pressure liquid pipe, a low-pressure air pipe and a high-pressure air pipe. The outdoor unit includes: a compressor, a first reversing assembly, and a second reversing assembly , Outdoor heat exchanger, heating device and control device. The heating device heats the refrigerant flowing from the low-pressure air pipe to the air return port, and the control device is connected with the heating device to control the heating device to be turned on or off. According to the outdoor unit of the three-pipe multi-connection system of the present invention, by setting the heating device and the control device, the control device can control the heating device to heat the low-pressure air pipe, so that the liquid refrigerant in the low-pressure air pipe can be heated and vaporized into a gaseous refrigerant, effectively preventing It prevents the liquid refrigerant from entering the compressor and causing "liquid shock" to damage the compressor, improves the working performance of the compressor, and then improves the heat transfer performance of the outdoor unit.

Description

Outdoor unit and control method of three-control multi-connection system

technical field

The present invention relates to the technical field of household electrical appliances, in particular, to an outdoor unit and a control method of a three-control multi-connection system.

Background technique

In the related technology, when the outside air temperature of the air conditioner is low, the outdoor heat exchanger cannot form a condensing high pressure, so that it cannot generate an effective pressure difference to press the refrigerant from the outdoor unit to the inner unit side, which usually results in less refrigerant on the indoor side and less refrigerant on the indoor side. After absorbing heat, the refrigerant becomes superheated gas and exits the indoor unit, but because the temperature of the outdoor unit is too low, when a small amount of superheated gas meets the low outdoor temperature, it will be liquefied into a low-temperature supercooled liquid and returned to the low pressure of the outdoor compressor. tank, because the circulation volume of the system is too small, the state of the refrigerant returning to the outdoor unit is saturated with liquid, which will not only affect the life of the compressor, but also because the compressor will have wet compression protection and cannot effectively increase the frequency. The amount of refrigerant circulation cannot be increased, and the system enters a vicious circle.

Contents of the invention

The present invention aims to solve at least one of the technical problems existing in the prior art. Therefore, the present invention proposes an outdoor unit of a three-control multi-connection system, which has the advantages of simple structure and stable operation.

The present invention also proposes a three-control multi-connection system, the three-control multi-connection system includes the outdoor unit of the above-mentioned three-control multi-connection system.

The invention also proposes a control method of the three-control multi-line system, which has the advantages of convenient operation and stable operation.

According to the outdoor unit of the three-pipe multi-connection system of the embodiment of the present invention, the outdoor unit is provided with a high-pressure liquid pipe, a low-pressure air pipe and a high-pressure air pipe, and the outdoor unit includes: a compressor with an exhaust port and The air return port, the air return port is connected to the low-pressure air pipe; the first reversing assembly, the first reversing assembly includes a first valve port to a third valve port, and the first valve port is connected to the second valve port port and the third valve port are switched and communicated, the first valve port is connected with the exhaust port, and the second valve port is connected with the low-pressure air pipe; the second reversing assembly, the second reversing assembly The assembly includes a first port to a third port, the first port is switched to communicate with the second port and the third port, the first port is connected to the exhaust port, and the second port is connected to the The low-pressure air pipe is connected, the third port is connected with the high-pressure air pipe; the outdoor heat exchanger, the first end of the outdoor heat exchanger is connected with the third valve port, and the second port of the outdoor heat exchanger The end is connected with the high-pressure liquid pipe; the heating device for heating the refrigerant flowing from the low-pressure air pipe to the return air port; the control device, the control device is connected with the heating device to control the opening or closing of the heating device .

According to the outdoor unit of the three-pipe multi-connection system of the embodiment of the present invention, by setting the heating device and the control device, the control device can control the heating device to heat the low-pressure air pipe, so that the liquid refrigerant in the low-pressure air pipe can be heated and vaporized into a gaseous refrigerant. It effectively prevents the liquid refrigerant from entering the compressor to cause "liquid shock" and damages the compressor, improves the working performance of the compressor, and further improves the heat exchange performance of the outdoor unit.

According to some embodiments of the present invention, a gas-liquid separator is also included, the gas-liquid separator includes an inlet and a gas outlet, the inlet is connected to the low-pressure gas pipe through a first refrigerant pipeline, and the gas outlet is connected through a second The refrigerant pipeline is connected with the air return port.

In some embodiments of the present invention, the heating device includes a first heating element provided on the gas-liquid separator.

According to some embodiments of the present invention, the first heating element is arranged on the outer wall of the shell of the gas-liquid separator.

In some embodiments of the present invention, the heating device includes a second heating element for heating the refrigerant in the first refrigerant pipeline.

According to some embodiments of the present invention, the heating device includes a third heating element for heating the refrigerant in the second refrigerant pipeline.

In some embodiments of the present invention, there are multiple outdoor heat exchangers, multiple first reversing assemblies, multiple outdoor heat exchangers and multiple first reversing assemblies Correspondingly, each of the first valve ports is connected to the exhaust port, each of the second valve ports is connected to the low-pressure air pipe, and each of the third valve ports is connected to the corresponding outdoor heat exchange port. connected to the device.

The three-control multi-connected system according to the embodiment of the present invention includes: an outdoor unit, the outdoor unit is the above-mentioned outdoor unit; a plurality of indoor units, each of which includes an indoor heat exchanger, and each of the The first end of the indoor heat exchanger is connected to the low-pressure air pipe through the first control valve, the first end of each indoor heat exchanger is connected to the high-pressure air pipe through the second control valve, and each indoor heat exchanger is connected to the high-pressure air pipe through the second control valve. The second end of the heater is connected with the high-pressure liquid pipe through a throttling element.

According to the three-pipe multi-connection system of the embodiment of the present invention, by setting the heating device and the control device, the control device can control the heating device to heat the low-pressure air pipe, so that the liquid refrigerant in the low-pressure air pipe can be heated and vaporized into a gaseous refrigerant, effectively preventing the The liquid refrigerant enters the compressor to cause "liquid shock" and damages the compressor, which improves the working performance of the compressor, thereby improving the working performance of the three-pipe multi-connected system.

According to the control method of the three-pipeline multi-connection system according to the embodiment of the present invention, the three-pipeline multi-connection system is the above-mentioned three-pipeline multi-connection system, and the control method includes the following steps: detecting the outdoor ambient temperature in cooling mode; When the outdoor environment temperature is lower than the set temperature, the heating device is controlled to be turned on to heat the refrigerant; when the outdoor environment temperature is higher than the set temperature, the heating device is controlled to be turned off.

According to the control method of the three-pipe multi-connected system of the embodiment of the present invention, when the liquid refrigerant content in the refrigerant returned to the compressor is high, the heating device can be turned on by the control device to heat the refrigerant, so that the liquid refrigerant can be vaporized into a gaseous refrigerant , to prevent "liquid shock" to the compressor; when the liquid refrigerant content in the refrigerant returned to the compressor is small, the heating device can be turned off through the control device, thereby reducing the heat waste of the heating device, saving energy and reducing consumption.

According to some embodiments of the present invention, the following steps are also included: when the heating device is turned on, detecting the low-pressure pressure on the low-pressure side of the outdoor heat exchanger, and calculating the degree of superheat of the return air; (the degree of superheat of the return air is obtained by detecting the return air pressure and the return air The calculation method is obtained by calculating the air temperature, and the calculation method is a conventional method) When the low-pressure pressure<the first predetermined value A or the degree of superheat of the return air<the first set value C, the heating device remains on; when the first predetermined value A≤low pressure When the pressure ≤ the second predetermined value B or the first set value C ≤ low pressure ≤ the second set value D, when the power supply voltage of the heating device is adjustable, reduce the power supply voltage of the heating device, and when the heating device When the power supply voltage of the device is not adjustable, the heating device is controlled to be turned on intermittently; when the low pressure > the second predetermined value B or the low pressure > the second set value D, the heating device is controlled to be turned off.

Additional aspects 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.

Description of drawings

The above and/or additional aspects and advantages of the present invention will become apparent and comprehensible from the description of the embodiments in conjunction with the following drawings, wherein:

Fig. 1 is a schematic structural diagram of a three-pipe multi-connection system according to an embodiment of the present invention, wherein the three-pipe multi-connection system is in cooling mode, and the direction indicated by the arrow is the refrigerant flow direction;

Fig. 2 is a schematic structural diagram of a three-pipe multi-connected system according to an embodiment of the present invention, wherein the three-pipe multi-connected system is in a heating mode, and the direction indicated by the arrow is the refrigerant flow direction.

Reference signs:

High-pressure liquid pipe 110, low-pressure air pipe 120, high-pressure air pipe 130,

Compressor 20, exhaust port 210, air return port 220,

The first reversing assembly 30, the first valve port 310, the second valve port 320, the third valve port 330,

The second reversing assembly 40, the first port 410, the second port 420, the third port 430,

Outdoor heat exchanger 50,

heating device 60, a first heating element 610, a second heating element 620, a third heating element 630,

Gas-liquid separator 70, inlet 710, gas outlet 720, first refrigerant pipeline 730, second refrigerant pipeline 740,

Indoor unit 800, indoor heat exchanger 810, first control valve 811, second control valve 812,

Three control multi-line system 1000.

Detailed ways

Embodiments of the present invention are described in detail below, examples of which are shown in the drawings, wherein the same or similar reference numerals designate the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the figures are exemplary only for explaining the present invention and should not be construed as limiting the present invention.

In describing the present invention, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "bottom", "inner", "outer", etc. indicate The orientation or positional relationship is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation or be configured in a specific orientation. and operation, and therefore should not be construed as limiting the invention. In addition, the features defined as "first" and "second" may explicitly or implicitly include one or more of these features. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

In the description of the present invention, it should be noted that unless otherwise specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection. Connected, or integrally connected; it can be mechanically connected or electrically connected; it can be directly connected or indirectly connected through an intermediary, and it can be the internal communication of two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention in specific situations.

The outdoor unit of the three-control multi-split system 1000 according to the embodiment of the present invention will be described below with reference to FIG. 1 and FIG. 2 .

As shown in FIGS. 1 and 2 , the outdoor unit is provided with a high-pressure liquid pipe 110 , a low-pressure air pipe 120 and a high-pressure air pipe 130 . It should be noted that the "high-pressure liquid pipe 110, low-pressure air pipe 120, and high-pressure air pipe 130" mentioned here are defined according to the flow direction of the refrigerant in the three-pipe multi-line system 1000, not according to the specific value of the pressure when the refrigerant flows in the pipes. Defined. The outdoor unit includes: a compressor 20, a first reversing assembly 30, a second reversing assembly 40, an outdoor heat exchanger 50, a heating device 60 and a control device (not shown in the figure).

Specifically, as shown in FIGS. 1 and 2 , the compressor 20 is provided with an exhaust port 210 and an air return port 22 , and the air return port 220 is connected to the low-pressure air pipe 120 . Thus, the refrigerant can return to the compressor 20 from the air return port 220 to be compressed, and the high-temperature and high-pressure gaseous refrigerant compressed by the compressor 20 can be discharged from the compressor 20 through the exhaust port 210 .

The first reversing assembly 30 includes a first valve port 310 to a third valve port 330 , the first valve port 310 is switched and communicated with the second valve port 320 and the third valve port 330 , and the first valve port 310 is connected with the exhaust port 210 , the second valve port 320 is connected with the low-pressure air pipe 120 . Thus, through the first reversing assembly 30 to switch the on-off of the first valve port 310 to the third valve port 330, the flow direction of the switching refrigerant can be adjusted, so as to realize the three-pipe multi-connected system 1000 in the cooling mode and the heating mode. Demand for different flow directions of refrigerant.

The second reversing assembly 40 includes a first port 410 to a third port 430, the first port 410 is switched and communicated with the second port 420 and the third port 430, the first port 410 is connected with the exhaust port 210, and the second port 420 is connected with the exhaust port 430. The low-pressure air pipe 120 is connected, and the third port 430 is connected with the high-pressure air pipe 130 . Thus, through the second reversing assembly 40 to switch the on-off of the first port 410 to the third port 430, the flow direction of the switching refrigerant can be adjusted, so that the three-pipe multi-connected system 1000 can control the refrigerant in the cooling mode and the heating mode. different flow requirements.

The first end of the outdoor heat exchanger 50 is connected to the third valve port 330 , and the second end of the outdoor heat exchanger 50 is connected to the high-pressure liquid pipe 110 . The heating device 60 heats the refrigerant flowing from the low-pressure air pipe 120 to the air return port 220, thus, the heating device 60 heats the refrigerant in the low-pressure air pipe 120, so that the liquid refrigerant in the low-pressure air pipe 120 can be vaporized into a gaseous refrigerant, preventing The entry of the liquid refrigerant into the compressor 20 causes a "liquid hammer" phenomenon of the compressor 20, which affects the working performance of the compressor 20.

The control device is connected with the heating device 60 to control the heating device 60 to be turned on or off. Thus, the heating device 60 can be controlled to be turned on or off by the control device. When there is liquid refrigerant in the low-pressure gas pipe 120, the heating device 60 can be turned on by the control device to heat the low-pressure gas pipe 120, so that the liquid refrigerant in the low-pressure gas pipe 120 can To prevent the liquid refrigerant from entering the compressor 20 and affecting the performance of the compressor 20; when there is no liquid refrigerant in the low-pressure air pipe 120 or the liquid refrigerant content is very small, the heating device 60 can be turned off by the control device, thereby saving consumption.

According to the outdoor unit of the three-pipe multi-connection system 1000 of the embodiment of the present invention, by setting the heating device 60 and the control device, the control device can control the heating device 60 to heat the low-pressure air pipe 120, so that the liquid refrigerant in the low-pressure air pipe 120 can be heated by the heated gas. Turning into a gaseous refrigerant effectively prevents the liquid refrigerant from entering the compressor 20 to cause wet compression of the compressor 20, improves the working performance of the compressor 20, and further improves the heat exchange performance of the outdoor unit.

According to some embodiments of the present invention, as shown in FIG. 1 and FIG. 2 , the outdoor unit may further include a gas-liquid separator 70 , the gas-liquid separator 70 includes an inlet 710 and a gas outlet 720 , and the inlet 710 passes through a first refrigerant pipeline 730 It is connected with the low-pressure gas pipe 120 , and the gas outlet 720 is connected with the gas return port 220 through the second refrigerant pipeline 740 . Thus, the refrigerant in the low-pressure gas pipe 120 can enter the gas-liquid separator 70 from the inlet 710 through the first refrigerant pipeline 730 for gas-liquid separation, and the gaseous refrigerant obtained after gas-liquid separation is discharged from the gas outlet 720 and passed through The second refrigerant pipeline 740 enters into the compressor 20 from the air return port 220 . Therefore, by providing the gas-liquid separator 70 , the content of the liquid refrigerant returned to the compressor 20 is effectively reduced, and the operation stability of the compressor 20 is improved.

In some embodiments of the present invention, the heating device 60 may include a first heating element 610 disposed on the gas-liquid separator 70 . Thus, the first heating element 610 can be used to heat the refrigerant inside the gas-liquid separator 70 and at the inlet 710 and the gas outlet 720 of the gas-liquid separator 70, effectively reducing the liquid refrigerant content returned to the compressor 20, The working performance of the compressor 20 is improved.

According to some embodiments of the present invention, the first heating element 610 is disposed on the outer wall of the housing of the gas-liquid separator 70 . Thereby, a fixed assembly of the first heating element 610 is facilitated. Moreover, by arranging the first heating element 610 on the outer peripheral wall of the shell of the gas-liquid separator 70 , the first heating element 610 can be used to directly heat the refrigerant in the gas-liquid separator 70 , reducing heat loss and waste.

In some embodiments of the present invention, the heating device 60 may include a second heating element 620 for heating the refrigerant in the first refrigerant pipeline 730 . Thus, by using the second heating element 620 to heat the refrigerant in the first refrigerant pipeline 730, the liquid refrigerant in the first refrigerant pipeline 730 is vaporized into a gaseous refrigerant, which reduces the pressure in the first refrigerant pipeline 730. The liquid refrigerant content improves the working performance of the compressor 20 .

According to some embodiments of the present invention, the heating device 60 includes a third heating element 630 for heating the refrigerant in the second refrigerant pipeline 740 . Thus, by using the third heating element 630 to heat the refrigerant in the second refrigerant pipeline 740, the liquid refrigerant in the second refrigerant pipeline 740 is vaporized into a gaseous refrigerant, reducing the pressure in the second refrigerant pipeline 740. The liquid refrigerant content improves the working performance of the compressor 20 .

In some embodiments of the present invention, as shown in FIG. 1 and FIG. 2, there may be multiple outdoor heat exchangers 50, multiple first reversing assemblies 30, multiple outdoor heat exchangers 50 and multiple second A reversing assembly 30 is provided in one-to-one correspondence, each first valve port 310 is connected to the exhaust port 210, each second valve port 320 is connected to the low-pressure air pipe 120, and each third valve port 330 is connected to the corresponding outdoor heat exchange Device 50 is connected. It can be understood that by arranging multiple outdoor heat exchangers 50 , the effective heat exchange area of the outdoor heat exchangers 50 is increased, thereby improving the heat exchange performance of the outdoor heat exchangers 50 . By setting a plurality of first reversing assemblies 30 corresponding to a plurality of outdoor heat exchangers 50 one-to-one, the corresponding first reversing assemblies 30 can be used to control and adjust the flow direction of the refrigerant, so as to realize the three-pipe multi-connected system 1000 in refrigeration and Different flow requirements of refrigerant in heating mode.

According to the three-control multi-connection system 1000 of the embodiment of the present invention, the three-control multi-connection system 1000 includes: an outdoor unit and a plurality of indoor units 800 .

Wherein, the outdoor unit is the above-mentioned outdoor unit, and each indoor unit 800 includes an indoor heat exchanger 810 , and the first end of each indoor heat exchanger 810 is connected to the low-pressure air pipe 120 through a first control valve 811 . Thus, the connection between the indoor heat exchanger 810 and the low-pressure air pipe 120 can be controlled through the first control valve 811 . The first end of each indoor heat exchanger 810 is connected to the high-pressure air pipe 130 through the second control valve 812 , thus, the connection between the indoor heat exchanger 810 and the high-pressure air pipe 130 can be controlled through the second control valve 812 . The second end of each indoor heat exchanger 810 is connected to the high-pressure liquid pipe 110 through a throttling element. Thus, by providing the throttling element, the refrigerant flowing through the throttling element can be throttled and decompressed, and the flow parameters of the refrigerant can be adjusted.

According to the three-pipe multi-line system 1000 of the embodiment of the present invention, by setting the heating device 60 and the control device, the control device can control the heating device 60 to heat the low-pressure air pipe 120, so that the liquid refrigerant in the low-pressure air pipe 120 can be heated and vaporized into a gaseous state The refrigerant effectively prevents the liquid refrigerant from entering the compressor 20 to cause "liquid shock" and damages the compressor 20, improves the working performance of the compressor 20, and further improves the heat exchange performance of the outdoor unit.

According to the control method of the three-control multi-connection system 1000 according to the embodiment of the present invention, the three-control multi-connection system 1000 is the above-mentioned three-control multi-connection system 1000, and the control method includes the following steps:

Detect the outdoor ambient temperature in cooling mode;

When the outdoor ambient temperature is lower than the set temperature, the heating device is controlled to be turned on to heat the refrigerant. Thus, the heating device is used to heat the refrigerant to vaporize the liquid refrigerant into a gaseous refrigerant, effectively avoiding the problem that the liquid refrigerant enters the compressor and affects the performance of the compressor.

When the outdoor ambient temperature is higher than the set temperature, the control heating device is turned off. Thereby, the heat waste of the heating device can be reduced, saving energy and reducing consumption.

According to the control method of the three-pipe multi-connection system 1000 of the embodiment of the present invention, when the liquid refrigerant content in the refrigerant returned to the compressor 20 is high, the heating device 60 can be turned on by the control device to heat the refrigerant to vaporize the liquid refrigerant It is a gaseous refrigerant to prevent "liquid shock" to the compressor 20; when the liquid refrigerant content in the refrigerant returned to the compressor 20 is small, the heating device 60 can be turned off by the control device, thereby reducing the heat waste of the heating device 60 and saving energy Reduce consumption.

According to some embodiments of the present invention, the following steps may also be included: when the heating device is turned on, detecting the low-pressure pressure on the low-pressure side of the outdoor heat exchanger and calculating the degree of superheat of the return air. It should be noted that the "return air superheat" mentioned here is calculated by detecting the return air pressure and return air temperature, and the calculation method is a conventional method, which will not be repeated here.

When the low-pressure pressure<the first predetermined value A or the degree of superheat of the return air<the first set value C, the heating device remains on. Thus, the liquid refrigerant can be heated to vaporize the liquid refrigerant into a gaseous refrigerant, preventing the liquid refrigerant from entering the compressor and causing a "liquid hammer" phenomenon.

When the first predetermined value A≤low pressure≤the second predetermined value B or the first set value C≤low pressure≤the second set value D, when the power supply voltage of the heating device is adjustable, the power supply voltage of the heating device is reduced, When the power supply voltage of the heating device is not adjustable, the heating device is controlled to be turned on intermittently. Thereby, the heat waste of the heating device can be reduced, saving energy and reducing consumption.

When the low pressure > the second predetermined value B or the low pressure > the second set value D, the control heating device is turned off. It has been verified by experiments that when the following conditions are met: low pressure > the second predetermined value B or low pressure > the second set value D , The liquid refrigerant content in the refrigerant returned to the compressor is very small. Thus, turning off the heating device can reduce the heat waste of the heating device, saving energy and reducing consumption.

The cooling working mode and heating working mode of the three-pipe multi-connected system 1000 according to the embodiment of the present invention will be described in detail below with reference to FIG. 1 and FIG. 2 in a specific embodiment.

As shown in Figure 1, when the three-pipe multi-connected system 1000 is in the cooling mode, the high-temperature and high-pressure gaseous refrigerant discharged from the compressor 20 flows to the first reversing assembly 30, and the first valve port 310 communicates with the third valve port 330. The high-pressure gaseous refrigerant enters the outdoor heat exchanger 50 through the first valve port 310 and the third valve port 330 in sequence. It flows into the high-pressure liquid pipe 110 and enters the indoor heat exchanger 810, where it evaporates and absorbs heat in the indoor heat exchanger 810, thereby realizing the indoor cooling function. The refrigerant after heat exchange in the indoor heat exchanger 810 enters the low-pressure gas pipe 120, and the refrigerant in the low-pressure gas pipe 120 enters the gas-liquid separator 70 from the inlet 710. The outlet 720 flows out of the gas-liquid separator 70 and returns to the compressor 20 from the air return port 220 to complete the refrigeration cycle of the refrigerant. Wherein, when the refrigerant flows through the first refrigerant pipeline 730, the gas-liquid separator 70 and the second refrigerant pipeline 740, the second heating element 620, the first heating element 610 and the third heating element 630 respectively heat it, so that The liquid refrigerant is vaporized into a gaseous refrigerant, which further reduces the content of the liquid refrigerant, prevents the compressor 20 from “liquid hammering”, and improves the performance of the compressor 20.

As shown in Figure 2, when the three-pipe multi-connected system 1000 is in the heating mode, the high-temperature and high-pressure gaseous refrigerant discharged from the compressor 20 flows to the second reversing assembly 40, and the first port 410 communicates with the third port 430. The gaseous refrigerant enters the indoor heat exchanger 810 through the first port 410 and the third port 430 in sequence, and the high-temperature and high-pressure gaseous refrigerant releases heat in the indoor heat exchanger 810 to realize the indoor heating function. The refrigerant after heat exchange becomes a high-pressure liquid refrigerant, and the high-pressure liquid refrigerant flows into the high-pressure liquid pipe 110 and enters the outdoor heat exchanger 50 , where heat exchange is performed. The refrigerant after heat exchange in the outdoor heat exchanger 50 enters the low-pressure air pipe 120, and the refrigerant in the low-pressure air pipe 120 enters the gas-liquid separator 70 from the inlet 710. The outlet 720 flows out of the gas-liquid separator 70 and returns to the compressor 20 from the air return port 220 to complete the heating cycle of the refrigerant.

Thus, by setting the heating device 60 and the control device, the control device can control the heating device 60 to heat the low-pressure gas pipe 120, so that the liquid refrigerant in the low-pressure gas pipe 120 can be heated and vaporized into a gaseous refrigerant, effectively preventing the liquid refrigerant from entering the compressed air. The compressor 20 is damaged due to the phenomenon of "liquid hammer" in the compressor 20, which improves the working performance of the compressor 20 and further improves the heat exchange performance of the outdoor unit.

In the description of this specification, references to the terms "one embodiment," "some embodiments," "exemplary embodiments," "example," "specific examples," or "some examples" are intended to mean that the implementation A specific feature, structure, material, or characteristic described by an embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Although the embodiments of the present invention have been shown and described, those skilled in the art can understand that various changes, modifications, substitutions and modifications can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the invention is defined by the claims and their equivalents.

Claims (10)

1. An outdoor unit of a three-pipe multi-connection system, characterized in that the outdoor unit is provided with a high-pressure liquid pipe, a low-pressure air pipe and a high-pressure air pipe, and the outdoor unit includes: A compressor, the compressor is provided with an exhaust port and an air return port, and the air return port is connected to the low-pressure air pipe; A first reversing assembly, the first reversing assembly includes a first valve port to a third valve port, the first valve port is switched and communicated with the second valve port and the third valve port, and the first valve port is switched and communicated with the second valve port and the third valve port. A valve port is connected to the exhaust port, and the second valve port is connected to the low-pressure air pipe; A second reversing assembly, the second reversing assembly includes a first port to a third port, the first port is in switching communication with the second port and the third port, and the first port is connected to the third port The exhaust port is connected, the second port is connected with the low-pressure air pipe, and the third port is connected with the high-pressure air pipe; An outdoor heat exchanger, the first end of the outdoor heat exchanger is connected to the third valve port, and the second end of the outdoor heat exchanger is connected to the high-pressure liquid pipe; a heating device for heating the refrigerant flowing from the low-pressure air pipe to the air return port; A control device, the control device is connected with the heating device to control the heating device to be turned on or off. 2. The outdoor unit of the three-pipe multi-line system according to claim 1, further comprising a gas-liquid separator, the gas-liquid separator includes an inlet and a gas outlet, and the inlet passes through the first refrigerant pipeline It is connected with the low-pressure gas pipe, and the gas outlet is connected with the gas return port through the second refrigerant pipeline. 3. The outdoor unit of the three-pipe multi-split system according to claim 2, wherein the heating device comprises a first heating element provided on the gas-liquid separator. 4. The outdoor unit of the three-pipe multi-line system according to claim 3, wherein the first heating element is arranged on the outer wall of the shell of the gas-liquid separator. 5. The outdoor unit of the three-pipe multi-split system according to claim 2, wherein the heating device comprises a second heating element for heating the refrigerant in the first refrigerant pipeline. 6. The outdoor unit of the three-pipe multi-split system according to claim 2, wherein the heating device comprises a third heating element for heating the refrigerant in the second refrigerant pipeline. 7. The outdoor unit of the three-control multi-connection system according to any one of claims 1-6, characterized in that there are multiple outdoor heat exchangers, multiple first reversing components, multiple Each of the outdoor heat exchangers is arranged in one-to-one correspondence with a plurality of the first reversing assemblies, each of the first valve ports is connected to the exhaust port, and each of the second valve ports is connected to the low pressure port. The air pipes are connected, and each of the third valve ports is connected with the corresponding outdoor heat exchanger. 8. A three-control multi-connection system, characterized in that it comprises: An outdoor unit, the outdoor unit is the outdoor unit according to any one of claims 1-7; A plurality of indoor units, each of which includes an indoor heat exchanger, the first end of each of the indoor heat exchangers is connected to the low-pressure air pipe through a first control valve, and each of the indoor heat exchangers The first end is connected with the high-pressure air pipe through the second control valve, and the second end of each indoor heat exchanger is connected with the high-pressure liquid pipe through a throttling element. 9. A control method for a three-control multi-connection system, the three-control multi-connection system is the three-control multi-connection system according to claim 8, wherein the control method comprises the following steps: Detect the outdoor ambient temperature in cooling mode; When the outdoor environment temperature is lower than the set temperature, the heating device is controlled to be turned on to heat the refrigerant; when the outdoor environment temperature is higher than the set temperature, the heating device is controlled to be turned off. 10. The control method of the three-control multi-line system according to claim 9, further comprising the steps of: When the heating device is turned on, detect the low pressure on the low pressure side of the outdoor heat exchanger and calculate the superheat of the return air; When the low pressure is less than the first predetermined value A or the degree of superheat of the return gas is less than the first set value C, the heating device remains on; When the first predetermined value A ≤ low pressure ≤ second predetermined value B or the first set value C ≤ low pressure ≤ second set value D, when the power supply voltage of the heating device is adjustable, reduce the heating device The power supply voltage of the heating device is controlled to turn on the heating device intermittently when the power supply voltage of the heating device is not adjustable; When the low pressure>the second predetermined value B or the low pressure>the second set value D, the heating device is controlled to be turned off.