阅读说明：本技术 回油控制方法、装置及空调 (Oil return control method and device and air conditioner ) 是由 吴娇娇 于 2021-06-25 设计创作，主要内容包括：本发明提供了一种回油控制方法、装置及空调,涉及空调器技术领域,为解决现有压缩机油量控制需要选择特殊的机型,不仅成本较高,而且,还存在与其他机型不匹配的问题而设计。该回油控制方法应用于空调器,空调器的压缩机的多余油排出管设置有第一温度传感器,该方法包括基于第一温度传感器检测多余油排出管的温度,得到多余油排出管温度；基于多余油排出管温度判断压缩机是否油量不足；如果是,控制压缩机进入回油阶段。本发明使得在压缩机选型时,无需选择内部配置有浮子开关和电容式传感器等油面高度检测装置的特殊压缩机,成本较低,且可通过其他机型实现通用化。(The invention provides an oil return control method, an oil return control device and an air conditioner, relates to the technical field of air conditioners, and aims to solve the problems that the existing compressor needs to select a special machine type for oil quantity control, the cost is high, and the existing compressor is not matched with other machine types. The oil return control method is applied to an air conditioner, a redundant oil discharge pipe of a compressor of the air conditioner is provided with a first temperature sensor, and the method comprises the steps of detecting the temperature of the redundant oil discharge pipe based on the first temperature sensor to obtain the temperature of the redundant oil discharge pipe; judging whether the oil quantity of the compressor is insufficient or not based on the temperature of the redundant oil discharge pipe; and if so, controlling the compressor to enter an oil return stage. The invention has the advantages that when the type of the compressor is selected, the special compressor which is internally provided with the oil level height detection devices such as the float switch and the capacitance sensor is not required to be selected, the cost is lower, and the generalization can be realized by other types.)

1. An oil return control method is characterized in that the method is applied to an air conditioner, and a redundant oil discharge pipe (54) of a compressor of the air conditioner is provided with a first temperature sensor (55); the method comprises the following steps: detecting the temperature of the excess oil discharge pipe (54) based on the first temperature sensor (55) to obtain the temperature of the excess oil discharge pipe;

judging whether the oil quantity of the compressor is insufficient or not based on the temperature of the excess oil discharge pipe;

and if so, controlling the compressor to enter an oil return stage.

2. The oil return control method according to claim 1, wherein the step of determining whether the amount of oil in the compressor is insufficient based on the excess oil discharge pipe temperature includes:

detecting the temperature of a discharge pipe of the compressor;

and when the difference value between the temperature of the exhaust pipe and the temperature of the redundant oil discharge pipe is smaller than or equal to a first preset temperature, determining that the oil amount of the compressor is insufficient.

3. The oil return control method according to claim 2, characterized by further comprising:

acquiring the temperature of a redundant oil discharge pipe when the compressor enters an oil return stage to obtain the temperature of a first discharge pipe; when the running time of the compressor entering the oil return stage reaches a first preset time, taking the current temperature of the excess oil discharge pipe as the temperature of a second discharge pipe;

when the second discharge pipe temperature is lower than the first discharge pipe temperature, or when the difference between the discharge pipe temperature and the second discharge pipe temperature is higher than the first preset temperature, the compressor is controlled to exit the oil return stage.

4. The oil return control method according to claim 1, wherein the step of determining whether the amount of oil in the compressor is insufficient based on the excess oil discharge pipe temperature includes:

when the temperature of the surplus oil discharge pipe is greater than or equal to a second preset temperature within a second preset time, determining that the compressor has insufficient oil; and the change value of the ambient temperature outside the chamber in the second preset time is smaller than the preset temperature threshold.

5. The oil return control method according to claim 4, further comprising:

when the running time of the compressor entering the oil return stage reaches a second preset time, acquiring a second temperature increment of the temperature of the redundant oil discharge pipe within a third preset time;

and when the second temperature increment is smaller than the second preset temperature or when the temperature decrement of the temperature of the redundant oil discharge pipe in a third preset time is larger than or equal to a third preset temperature, controlling the compressor to exit the oil return stage.

6. The oil return control method according to claim 1, wherein the step of the air conditioner controlling the compressor to enter the oil return stage includes:

and increasing the rotating speed of the compressor to a first preset rotating speed, and opening the electronic expansion valve to the maximum opening degree for operation.

7. The oil return control method of claim 1, wherein the step of controlling the compressor to enter an oil return phase comprises: when the air conditioner comprises a plurality of compressors, the compressor in an oil quantity insufficient state is used as a target compressor, the rotating speed of the target compressor is controlled to be reduced to a second preset rotating speed, the rotating speeds of other compressors except the target compressor are controlled to be increased to a first preset rotating speed, and the electronic expansion valve is opened to the maximum opening degree for operation.

8. The utility model provides a compressor oil mass controlling means which characterized in that is applied to the air conditioner, the device includes: the temperature detection module (151) is used for detecting the temperature of the redundant oil discharge pipe (54) based on the first temperature sensor (55) to obtain the temperature of the redundant oil discharge pipe;

the judging module (152) is used for judging whether the oil quantity of the compressor is insufficient or not based on the temperature of the redundant oil discharge pipe; and the control oil return module (153) is used for controlling the air conditioner to enter an oil return stage when the oil quantity of the compressor is insufficient.

9. An air conditioner comprising a computer readable storage medium storing a computer program and a processor, the computer program being read and executed by the processor to implement the method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that it stores a computer program which, when read and executed by a processor, implements the method according to any one of claims 1-7.

Technical Field

The invention relates to the technical field of air conditioners, in particular to an oil return control method and device and an air conditioner.

Background

When the air conditioner is connected with a long connecting pipe or a plurality of indoor units, the phenomenon of insufficient oil quantity of the compressor can be caused by oil retention in the pipeline or the indoor units. In addition, when the air conditioner comprises a plurality of compressors connected in parallel, the phenomenon of insufficient oil quantity of the compressors can be caused due to the problem of uneven oil distribution among the compressors. To this type of air conditioner, the accessible detects the high presumption compressor oil volume of oil level, then, carries out the oil return operation and realizes the impartial distribution of compressor oil volume in order to take back the compressor oil that pipeline and indoor machine are detained in or carry out the even oily operation to effectively prevent the not enough problem of compressor oil volume.

Fig. 1 is a schematic diagram of detecting an oil amount of a compressor provided in a first related art, and fig. 2 is a schematic diagram of detecting an oil amount of a compressor provided in a second related art. Conventionally, the oil level detection of the compressor is usually realized by disposing an oil level detection device such as a float switch 11 (shown in fig. 1) or a capacitive sensor 21 (shown in fig. 2) inside the compressor. Although the method can achieve the purpose of detecting the oil level height of the compressor, when the compressor is selected, the special compressor with the oil level height detection device arranged inside needs to be selected, so that the cost is high, and the universalization problem that the compressor is not matched with other models exists.

In addition, in other solutions adopted in the prior art, only the oil level height detection of the compressor of the air conditioner provided with the oil reservoir can be realized.

Disclosure of Invention

The invention solves the technical problems that the existing compressor oil quantity control needs to select a special machine type, not only the cost is higher, but also the generalization problem that the oil quantity control is not matched with other machine types exists.

In order to solve the problems, the invention provides an oil return control method which is applied to an air conditioner, wherein a first temperature sensor is arranged on an excess oil discharge pipe of a compressor of the air conditioner; the method comprises the following steps: detecting the temperature of the excess oil discharge pipe based on the first temperature sensor to obtain the temperature of the excess oil discharge pipe; judging whether the oil quantity of the compressor is insufficient or not based on the temperature of the excess oil discharge pipe; and if so, controlling the compressor to enter an oil return stage.

According to the oil return control method provided by the invention, the first temperature sensor is arranged on the redundant oil discharge pipe of the compressor, so that the temperature of the redundant oil discharge pipe can be detected in real time by using the first temperature sensor in the running process of the compressor, whether the oil quantity of the compressor is insufficient or not can be judged in real time according to the temperature of the redundant oil discharge pipe, and the compressor is timely controlled to return oil, so that the oil quantity in the compressor is kept sufficient.

The method has the advantages that when the type of the compressor is selected, the special compressor with the oil level height detection device such as a float switch and a capacitance sensor arranged inside is not required to be selected, the cost is low, and the generalization can be realized through other types. In addition, even if the oil reservoir is not arranged in the air conditioner, the oil level of the compressor can be detected.

Further, the step of determining whether the amount of oil in the compressor is insufficient based on the temperature of the excess oil discharge pipe includes: detecting the temperature of a discharge pipe of the compressor; and when the difference value between the temperature of the exhaust pipe and the temperature of the redundant oil discharge pipe is smaller than or equal to a first preset temperature, determining that the oil amount of the compressor is insufficient. This method for determining whether the amount of compressor oil is insufficient is simple and reliable.

Further, still include: acquiring the temperature of a redundant oil discharge pipe when the compressor enters an oil return stage to obtain the temperature of a first discharge pipe; when the running time of the compressor entering the oil return stage reaches a first preset time, taking the current temperature of the excess oil discharge pipe as the temperature of a first discharge pipe; when the second discharge pipe temperature is lower than the first discharge pipe temperature, or when the difference between the discharge pipe temperature and the second discharge pipe temperature is higher than the first preset temperature, the compressor is controlled to exit the oil return stage. The condition that the compressor works abnormally due to the fact that the oil return amount of the compressor is large can be avoided by timely controlling the compressor to exit the oil return stage.

Further, the step of determining whether the amount of oil in the compressor is insufficient based on the temperature of the excess oil discharge pipe includes: when the temperature of the surplus oil discharge pipe is greater than or equal to a second preset temperature within a second preset time, determining that the compressor has insufficient oil; and the change value of the ambient temperature outside the chamber in the second preset time is smaller than the preset temperature threshold. According to the mode, the temperatures of the redundant oil discharge pipes at different moments are compared, the temperatures of other parts do not need to be acquired, and the cost is low.

Further, still include: when the running time of the compressor entering the oil return stage reaches a second preset time, acquiring a second temperature increment of the temperature of the redundant oil discharge pipe within a third preset time; and when the second temperature increment is smaller than the second preset temperature or when the temperature decrement of the temperature of the redundant oil discharge pipe in a third preset time is larger than or equal to a third preset temperature, controlling the compressor to exit the oil return stage. The mode of judging whether the compressor exits from the oil return operation can avoid the condition that the height of the oil level of the compressor cannot be normally detected due to the fluctuation of the exhaust temperature caused by the change of the external environment, and the detection result is accurate.

Further, the step of controlling the compressor to enter the oil return stage includes: and increasing the rotating speed of the compressor to a first preset rotating speed, and opening the electronic expansion valve to the maximum opening degree for operation. So set up, can make the quick oil return of compressor.

Further, the step of controlling the compressor to enter the oil return stage includes: when the air conditioner comprises a plurality of compressors, the compressor in an oil quantity insufficient state is used as a target compressor, the rotating speed of the target compressor is controlled to be reduced to a second preset rotating speed, the rotating speeds of other compressors except the target compressor are controlled to be increased to a first preset rotating speed, and the electronic expansion valve is opened to the maximum opening degree for operation. This way, when the air conditioner includes a plurality of compressors, the oil amount of each compressor can be controlled, so that the oil amount difference between the plurality of compressors can be eliminated.

The invention provides a compressor oil quantity control device, which is applied to an air conditioner, and comprises: the temperature detection module is used for detecting the temperature of the excess oil discharge pipe based on the first temperature sensor to obtain the temperature of the excess oil discharge pipe; the judging module is used for judging whether the oil quantity of the compressor is insufficient or not based on the temperature of the redundant oil discharge pipe; and the control oil return module is used for controlling the air conditioner to enter an oil return stage when the oil quantity of the compressor is insufficient.

The invention provides an air conditioner comprising a computer readable storage medium storing a computer program and a processor, the computer program being read and executed by the processor to implement the method as described above.

The invention provides a computer-readable storage medium, which stores a computer program, and when the computer program is read and operated by a processor, the oil return control method is realized.

The compressor oil amount control device, the air conditioner and the computer readable storage medium provided by the invention can achieve the same technical effects as the oil return control method, and therefore, the details are not repeated.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

FIG. 1 is a schematic diagram of the detection of compressor oil level as provided in the prior art;

fig. 2 is a schematic diagram illustrating the detection of the amount of oil in the compressor according to the second prior art;

fig. 3 is a schematic flow chart of an oil return control method according to an embodiment of the present invention;

fig. 4 is a schematic structural diagram of a compressor of an air conditioner according to an embodiment of the present invention;

fig. 5 is a schematic medium flow diagram of a compressor of an air conditioner according to an embodiment of the present invention in an operating state;

fig. 6 is a schematic diagram illustrating the flow of a medium when the amount of oil is large in a compressor of an air conditioner according to an embodiment of the present invention;

fig. 7 is a schematic diagram illustrating the flow of a medium when the amount of oil is small in a compressor of an air conditioner according to an embodiment of the present invention;

fig. 8 is a schematic flow chart illustrating a method for controlling oil return according to an embodiment of the present invention to determine whether the oil amount of the compressor is insufficient;

fig. 9 is a schematic flowchart illustrating a method for controlling oil return according to another embodiment of the present invention to determine whether the oil amount of the compressor is insufficient;

fig. 10 is a schematic flow chart of another oil return control method according to an embodiment of the present invention;

FIG. 11 is an exemplary plot of excess oil drain pipe temperature versus exhaust gas temperature for the oil return control method provided in FIG. 10;

fig. 12 is a schematic flow chart of another oil return control method according to an embodiment of the present invention;

FIG. 13 is an exemplary graph of excess oil drain temperature in the oil return control method provided in FIG. 12;

fig. 14 is a schematic structural diagram of a compressor oil amount control device according to an embodiment of the present invention.

Description of reference numerals:

11-a float switch; 21-a capacitive sensor; 31-an oil reservoir; 32-a temperature sensor;

51-a body; 52-suction pipe; 53-exhaust pipe; 54-excess oil discharge pipe; 55-a first temperature sensor; 56-oil;

61-low temperature oil; 62-low temperature air suction refrigerant; 63-high temperature exhaust refrigerant;

151-temperature detection module; 152-a judgment module; 153-control oil return module.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Fig. 3 is a schematic flowchart of an oil return control method according to an embodiment of the present invention, and fig. 4 is a schematic structural diagram of a compressor of an air conditioner according to an embodiment of the present invention. As shown in fig. 3, the present embodiment provides an oil return control method applied to an air conditioner, and particularly, as shown in fig. 4, an excess oil discharge pipe 54 of a compressor of the air conditioner is provided with a first temperature sensor 55. The oil return control method comprises the following steps:

s42: the temperature of the excess oil discharge pipe 54 is detected based on the first temperature sensor 55, and the excess oil discharge pipe temperature is obtained.

Referring to fig. 4, a suction pipe 52 and a discharge pipe 53 are connected to a compressor body 51, oil 56 is provided in the compressor body 51, an excess oil discharge pipe 54 is connected between the compressor body 51 and the discharge pipe 53, and a first temperature sensor 55 is mounted on a pipe wall of the excess oil discharge pipe 54 to detect a temperature of the excess oil discharge pipe 54.

The first temperature sensor 55 is attached to the outer wall of the excess oil discharge pipe 54, and the temperature detection portion thereof extends into the excess oil discharge pipe 54. When the temperature of the medium inside the excessive oil discharge pipe 54 changes, the temperature detection unit of the first temperature sensor 55 detects the temperature value, and obtains the temperature of the excessive oil discharge pipe. The arrangement mode has the advantages that the change of the surplus oil discharge pipe 54 is small, and the change cost is low.

S44: and judging whether the oil quantity of the compressor is insufficient or not based on the temperature of the redundant oil discharge pipe.

Fig. 5 is a schematic medium flow diagram of a compressor of an air conditioner according to an embodiment of the present invention in an operating state. As shown in fig. 5, during the operation of the compressor, low temperature oil 61 of the compressor is sucked through the suction pipe 52 together with the low temperature suction refrigerant 62, and the temperature of the low temperature oil is lower than the discharge temperature, wherein the low temperature oil 61 is retained at the bottom of the body 51 to be retained low temperature oil, and the refrigerant is compressed in the compressor to form a high temperature discharge refrigerant 63 and discharged through the discharge pipe 53. For example, when the compressor is operated in a normal operation mode for cooling, the discharge temperature is about 95 ℃ and the suction temperature is about 20 ℃, at this time, the temperature of the oil sucked into the compressor by the suction pipe 52 and the suction temperature are about 20 ℃, but the temperature of the oil is about 80 ℃ after the discharge refrigerant in the compressor is overheated. Therefore, as described below, the temperature of the excessive oil discharge pipe 54 varies depending on the oil level.

Fig. 6 is a schematic diagram of a medium flow of a compressor of an air conditioner according to an embodiment of the present invention when the oil amount is large. As shown in fig. 6, when the amount of the compressor oil increases and the oil level rises, the oil is discharged through the discharge pipe 53 together with the refrigerant via the excess oil discharge pipe 54, and at this time, the low temperature oil 61 flows through the excess oil discharge pipe 54, so that the temperature detected by the excess oil discharge pipe 54 is lower than the discharge temperature, for example, the temperature of the excess oil discharge pipe becomes 80 ℃ lower than the discharge temperature (95 ℃) in the rated cooling operation condition.

Fig. 7 is a schematic diagram of a medium flow of a compressor of an air conditioner according to an embodiment of the present invention when the amount of oil is small. As shown in fig. 7, when the amount of the compressor oil is reduced and the oil level is lowered, the oil is not discharged through the excess oil discharge pipe 54, and at this time, only the high-temperature exhaust refrigerant 63 passes through the excess oil discharge pipe 54, and the detected temperature is the same as the exhaust temperature, for example, under the rated condition refrigeration operation, the temperature of the excess oil discharge pipe is the same as the exhaust temperature, and is 95 ℃.

Based on the method, the oil level height of the compressor is calculated by detecting the temperature of the redundant oil discharge pipe.

S46: and if so, controlling the compressor to enter an oil return stage.

If the oil quantity of the compressor is insufficient, the fact that the oil quantity of the compressor is reduced and the oil level height is lowered is indicated, and at the moment, the compressor is controlled to enter an oil return stage to supplement oil to the compressor so as to guarantee normal operation of the compressor; if the oil quantity of the compressor is sufficient, the compressor is in a normal working state, and oil supplementing operation to the compressor is not needed.

Wherein, the comparison objects of the rise and the fall of the oil level are as follows: the connection height of the excessive oil discharge pipe 54 of the compressor. Generally, the connection height of the excessive oil discharge pipe 54 is lower than a specified oil amount (filling oil amount in the compressor factory) and higher than a critical oil amount height of the compressor (height that may cause an insufficient oil amount of the compressor).

According to the oil return control method provided by the invention, the first temperature sensor 55 is arranged on the excess oil discharge pipe 54 of the compressor, so that the temperature of the excess oil discharge pipe 54 can be detected in real time by using the first temperature sensor 55 in the running process of the compressor, whether the oil quantity of the compressor is insufficient or not can be judged in real time according to the temperature of the excess oil discharge pipe, and the oil return of the compressor is controlled in time, so that the oil quantity in the compressor is kept sufficient.

The method has the advantages that when the type of the compressor is selected, the special compressor with the oil level height detection device such as a float switch and a capacitance sensor arranged inside is not required to be selected, the cost is low, and the generalization can be realized through other types. In addition, even if the oil reservoir is not arranged in the air conditioner, the oil level of the compressor can be detected.

Fig. 8 is a schematic flowchart illustrating a method for controlling oil return according to an embodiment of the present invention to determine whether the oil amount of the compressor is insufficient. As shown in fig. 8, the step of determining whether the oil amount of the compressor is insufficient based on the temperature of the excess oil discharge pipe may include:

s92: the temperature of the discharge pipe of the compressor is detected.

Based on the above analysis, when the compressor oil amount increases and the oil level rises, the temperature detected by the extra oil discharge pipe 54 is lower than the discharge temperature, that is: the temperature of the excess oil discharge pipe is lower than that of the exhaust pipe; when the amount of the compressor oil decreases and the oil level decreases, the temperature detected by the excessive oil discharge pipe 54 is the same as the exhaust temperature, that is: the temperature of the excess oil discharge pipe is equal to that of the exhaust pipe. Therefore, the trend of the change of the oil quantity of the compressor can be obtained by detecting the temperature of the exhaust pipe of the compressor and comparing the temperature with the temperature of the redundant oil exhaust pipe.

In this embodiment, a second temperature sensor may be provided in the exhaust pipe 53, and the exhaust pipe temperature may be detected by the second temperature sensor.

S94: and when the difference value between the temperature of the exhaust pipe and the temperature of the redundant oil discharge pipe is less than or equal to a first preset temperature, determining that the oil amount of the compressor is insufficient.

Specifically, the decrease in the amount of compressor oil is continuous, and when the amount of oil in the compressor has just started to decrease, this may be caused by fluctuations in the amount of oil during operation of the compressor. As the amount of the compressor oil is continuously decreased, the amount of the oil introduced into the excessive oil discharge pipe 54 is also decreased, and accordingly, the temperature of the excessive oil discharge pipe 54 is gradually increased. When the temperature of the excess oil discharge pipe rises to a temperature that differs from the temperature of the exhaust pipe by less than or equal to a first preset temperature, it indicates that the amount of oil entering the excess oil discharge pipe 54 at this time is small, that is: the compressor oil amount is insufficient. This method for determining whether the amount of compressor oil is insufficient is simple and reliable.

Wherein the first preset temperature may be between 2 ℃ and 4 ℃, preferably 3 ℃.

Referring to fig. 3, the oil return control method further includes:

s461: acquiring the temperature of a redundant oil discharge pipe when the compressor enters an oil return stage to obtain the temperature of a first discharge pipe; and when the running time of the compressor entering the oil return stage reaches a first preset time, taking the current temperature of the excess oil discharge pipe as the temperature of the second discharge pipe.

That is, when the compressor enters the oil return stage and operates for a period of time, the oil amount of the compressor will gradually increase due to the oil return, the oil amount entering the excess oil discharge pipe 54 will also increase, and the temperature of the excess oil discharge pipe 54 will change, that is: the temperature of the excess oil discharge pipe will change from the first discharge pipe temperature to the second discharge pipe temperature.

It should be noted that, the method for determining the first preset time period may be: and actually measuring the time for the oil to return to the compressor, or calculating according to the length of an air pipe, the length of a liquid pipe and the flow rate of a refrigerant, wherein the length of the air pipe and the length of the liquid pipe are calculated according to the maximum length of the specification of the air conditioner. The specific calculation method comprises the following steps: the first preset duration is equal to the length of the gas pipe/the flow rate of the gas pipe + the length of the liquid pipe/the flow rate of the liquid pipe, wherein the flow rate of the gas pipe is equal to the volume of the cylinder of the compressor, the rotating speed of the compressor, the density of the refrigerant/the cross-sectional area of the gas pipe, and the flow rate of the liquid pipe is equal to the volume of the cylinder of the compressor, the rotating speed of the compressor, the density of the refrigerant/the cross-sectional area of the liquid pipe.

In this embodiment, the first preset time period may be between 5min and 10min, and is preferably 8 min.

S462: and when the temperature of the second discharge pipe is lower than that of the first discharge pipe, or when the difference between the temperature of the discharge pipe and the temperature of the second discharge pipe is higher than a first preset temperature, controlling the compressor to exit the oil return stage.

Specifically, the second discharge pipe temperature may be compared with the first discharge pipe temperature, and when the second discharge pipe temperature is less than the first discharge pipe temperature, it indicates that the current temperature of the excess oil discharge pipe 54 is decreasing compared to its previous time, that is: the amount of oil currently entering the excess oil discharge pipe 54 increases, and the oil supplied by the compressor in the oil return phase meets the requirements, so that the oil return phase can be exited.

Alternatively, the second discharge pipe temperature may be compared with the exhaust pipe temperature, and when the difference between the exhaust pipe temperature and the second exhaust pipe temperature is greater than the first preset temperature, it indicates that the current temperature of the excess oil discharge pipe 54 is greatly different from the exhaust pipe temperature, that is: the current temperature of the excess oil discharge pipe 54 is low, the amount of oil currently entering the excess oil discharge pipe 54 is increased, the oil supplied by the compressor in the oil return stage meets the requirement, and the oil return stage can be exited.

The condition that the compressor works abnormally due to the fact that the oil return amount of the compressor is large can be avoided by timely controlling the compressor to exit the oil return stage.

Fig. 9 is a schematic flowchart illustrating a method for controlling oil return according to another embodiment of the present invention to determine whether the oil amount of the compressor is insufficient. As shown in fig. 9, the step of determining whether the oil amount of the compressor is insufficient based on the temperature of the excessive oil discharge pipe may include:

s102: when the first temperature increment of the temperature of the surplus oil discharge pipe in the second preset time period is greater than or equal to the second preset temperature, determining that the oil amount of the compressor is insufficient; and the change value of the ambient temperature outside the chamber in the second preset time is smaller than the preset temperature threshold.

During the period that the outdoor environment temperature is basically stable, when the temperature of the excess oil discharge pipe rises more, namely the first temperature increment is greater than or equal to the second preset temperature, the fact that the oil amount entering the excess oil discharge pipe 54 is less at the moment is shown, the fluid in the excess oil discharge pipe 54 is changed into the exhaust refrigerant from the oil, and the compressor is in the state of insufficient oil amount. In this way, the temperatures of the excess oil discharge pipe 54 at different times are compared, so that the temperatures of other parts do not need to be acquired, and the cost is low. When the change value of the outdoor environment temperature in the chamber is less than the preset temperature threshold value for the second preset time period, it indicates that the outdoor environment temperature is substantially stable, and specifically, the preset temperature threshold value may be 1 ℃ to 2 ℃.

In this embodiment, the second preset duration may be the same as the first preset duration; the second preset temperature may be between 3 ℃ and 7 ℃, preferably 5 ℃.

Referring to fig. 3, the oil return control method further includes:

s463: and when the running time of the compressor entering the oil return stage reaches a second preset time, acquiring a second temperature increment of the temperature of the excess oil discharge pipe within a third preset time.

After the compressor runs for a period of time after oil return, the temperature of the excess oil discharge pipe 54 can be continuously detected within a third preset time period, a second temperature increment of the temperature of the excess oil discharge pipe within the third preset time period is obtained, and whether the oil return stage can be exited or not is determined according to the change of the second temperature increment.

When the external environment temperature changes, the suction pressure, the suction temperature and the discharge pressure of the compressor change along with the change, so that the temperature of the discharge pipe changes. Therefore, the temperature of the excessive oil discharge pipe also changes according to the change in the external environment temperature. When the external environment temperature changes, the temperature of the redundant oil discharge pipe changes, so that the oil level height of the compressor cannot be normally detected. In summary, it is necessary to perform the comparison of the temperature of the excess oil discharge pipe in a time when the change in the external environmental temperature is very small, that is, in the third preset time period.

In this embodiment, the third preset time period may be 4min to 6min, preferably 5 min. In the process, the temperature of the external environment is basically kept stable, and the oil level rising or falling is more accurate according to the temperature change of the excess oil discharge pipe.

S464: and when the second temperature increment is less than the second preset temperature or the temperature decrement of the temperature of the redundant oil discharge pipe within a third preset time is more than or equal to the third preset temperature, controlling the compressor to exit the oil return stage.

Specifically, when the second temperature increment of the excess oil discharge pipe 54 within the third preset time period in which the external environment temperature is substantially stable is smaller, it indicates that after a period of oil return, the temperature rise of the excess oil discharge pipe 54 is smaller, and the temperature of the excess oil discharge pipe 54 has already tended to be stable, at this time, the amount of oil in the excess oil discharge pipe 54 is sufficient, and the oil return stage can be exited.

Or, when the temperature of the excess oil discharge pipe is within a third preset time period in which the temperature of the external environment is basically stable, the temperature decrement is greater than or equal to the third preset temperature, which indicates that the temperature of the excess oil discharge pipe 54 drops greatly after a period of oil return, and the temperature drop can be used to estimate that the fluid in the excess oil discharge pipe 54 changes from the exhaust refrigerant to oil and the amount of oil in the excess oil discharge pipe 54 is large, so that the level of the oil surface of the compressor can be determined to be in the rising state, and the oil return stage can be exited.

The mode of judging whether the compressor exits from the oil return operation can avoid the condition that the height of the oil level of the compressor cannot be normally detected due to the fluctuation of the exhaust temperature caused by the change of the external environment, and the detection result is accurate.

Wherein the third preset temperature may be between 3 ℃ and 7 ℃, preferably 5 ℃.

Note that, when the air conditioner includes a plurality of compressors, the excessive oil discharge pipe 54 of each compressor is provided with a first temperature sensor 55. With this arrangement, the respective detection of the temperature of the excessive oil discharge pipe of each compressor can be realized by the respective first temperature sensors 55, thereby facilitating the independent control of the oil amount of each compressor.

With reference to fig. 3, specifically, the step of controlling the compressor to enter the oil return stage may include:

s465: and increasing the rotating speed of the compressor to a first preset rotating speed, and opening the electronic expansion valve to the maximum opening degree for operation.

By increasing the rotation speed of the compressor to the first preset rotation speed, oil stagnation in an air pipe connecting the outdoor unit and the indoor unit can be prevented. When the rotating speed of the compressor is low, the flow rate of the gaseous refrigerant is reduced, oil is retained in an air pipe connecting the outdoor unit and the indoor unit and cannot normally return to the compressor, and therefore the rotating speed of the compressor needs to be increased in oil return operation. In the process of oil return operation, the outdoor unit continues normal cooling or heating operation except the compressor, and the indoor unit which performs cooling or heating operation continues fan operation to maintain heating or cooling operation. Because the rotating speed of the compressor is increased and the electronic expansion valve of the indoor unit is opened, the situation of insufficient refrigerating and heating capacity can not occur.

S466: when the air conditioner comprises a plurality of compressors, the compressor with insufficient oil is taken as a target compressor, the rotating speed of the target compressor is controlled to be reduced to a second preset rotating speed, the rotating speeds of other compressors except the target compressor are controlled to be increased to a first preset rotating speed, and the electronic expansion valve is opened to the maximum opening degree for operation.

In the oil return operation, all the compressors need to be operated, and at this time, the compressor refrigerating machine oil having a high oil level flows to the excessive oil discharge pipe 54, and therefore, the discharge pipe discharges a large amount of oil. However, in the compressor having a low oil level, the excess oil discharge pipe 54 passes only the refrigerant, and therefore, the oil discharged from the discharge pipe is small. And the oil returning to the suction duct 52 of the compressor via the indoor unit is uniformly distributed to the compressors. In summary, by reducing the rotation speed of the compressor with a low oil level and increasing the rotation speed of the compressor with a high oil level, the oil level of the compressor with a high oil level can be reduced and the oil level of the compressor with a low oil level can be increased, so that the oil amount difference between the plurality of compressors can be eliminated.

When the temperature is up or the indoor unit is down, the fan is stopped to pass through the refrigerant. Because the indoor unit can not discharge air, the indoor unit can not carry out refrigeration or heating, and after the oil return operation, the normal refrigeration or heating operation is recovered. Specifically, the rotation speed of the compressor is recovered to the rotation speed before oil return operation, and the opening degree of the electronic expansion valve is also recovered to the opening degree before oil return operation.

In this embodiment, the first preset rotation speed may be 80% of the maximum rotation speed of the compressor, and the second preset rotation speed may be 30% of the maximum rotation speed of the compressor.

When the temperature of the redundant oil discharge pipes of all the compressors is judged to be low, the oil level height of each compressor is high, the oil quantity of each compressor is sufficient, and at the moment, each compressor can be controlled to exit the oil return stage. The mode of controlling the plurality of compressors to exit the oil return stage has simple control strategy and is easy to realize.

Fig. 10 is a schematic flow chart of another oil return control method according to an embodiment of the present invention, and as shown in fig. 10, the method includes:

s111: and starting.

S112: cooling operation or heating operation.

S113: the excess oil drain pipe temperature Top is detected.

S114: the exhaust temperature Td is detected.

S115: judging whether the Td-Top is less than 3 ℃, if so, executing S116; if not, the process returns to step S113.

S116: and (5) oil return operation.

S117: judging whether to continue the cooling operation or the heating operation, if so, executing S118; if not, the process returns to step S113.

S118: and (6) ending.

Fig. 11 is an exemplary graph of excess oil discharge pipe temperature and discharge air temperature in the oil return control method provided in fig. 10. As shown in fig. 11, when the difference between the excess oil discharge pipe temperature and the exhaust gas temperature is less than 3 ℃, it indicates that the amount of oil entering the excess oil discharge pipe 54 is reduced, that is: the oil amount of the compressor is reduced, the oil level of the compressor is lowered, and the compressor needs to be operated in an oil return mode.

Fig. 12 is a schematic flow chart of another oil return control method according to an embodiment of the present invention, and as shown in fig. 12, the method includes:

s130: and starting.

S131: cooling operation or heating operation.

S132: the elapsed time Tr is 0.

S133: detecting temperature Top of excess oil discharge pipe₀。

S134: judging whether Tr is greater than 5min, if yes, executing S135; if not, continuously judging whether Tr is larger than 5 min.

S135: detecting temperature Top of excess oil discharge pipe₁。

S136: judging whether to Top₁-Top₀>If yes, executing S137; if not, the process returns to the step S132.

S137: and (5) oil return operation.

S138: and judging whether the cooling operation or the heating operation is continued, if so, executing S139, otherwise, returning to the step of executing S132.

Fig. 13 is an exemplary graph of the temperature of the excess oil discharge pipe in the oil return control method provided in fig. 12. As shown in fig. 13, when the temperature rise of the excessive oil discharge pipe 54 is more than 5 ℃, it indicates that the amount of oil entering the excessive oil discharge pipe 54 is reduced, that is: the oil amount of the compressor is reduced, the oil level of the compressor is lowered, and the compressor needs to be operated in an oil return mode.

Fig. 14 is a schematic structural diagram of a compressor oil amount control device according to an embodiment of the present invention, the compressor oil amount control device is applied to an air conditioner, and as shown in fig. 14, the compressor oil amount control device includes:

a temperature detection module 151 for detecting the temperature of the excess oil discharge pipe 54 based on the first temperature sensor 55 to obtain the temperature of the excess oil discharge pipe;

a judging module 152, configured to judge whether the oil amount of the compressor is insufficient based on the temperature of the excess oil discharge pipe;

and the control oil return module 153 is used for controlling the air conditioner to enter an oil return stage when the oil quantity of the compressor is insufficient.

The oil quantity control device of the compressor can detect the temperature of the excess oil discharge pipe 54 in real time in the running process of the compressor, and judge whether the oil quantity of the compressor is insufficient or not in real time according to the temperature of the excess oil discharge pipe, so that the compressor is controlled to return oil in time, the oil quantity in the compressor is kept sufficient, the problem that a special machine type needs to be selected for oil quantity control of the compressor in the prior art is effectively solved, the cost is high, the universalization problem that the oil quantity of the compressor is not matched with other machine types exists, and the cost of an air conditioner is reduced.

The embodiment of the invention also provides an air conditioner, which comprises a computer readable storage medium and a processor, wherein the computer readable storage medium is used for storing a computer program, and the computer program is read by the processor and runs to realize the compressor frequency control method.

The embodiment of the present invention further provides a computer-readable storage medium, where the computer-readable storage medium stores a computer program, and when the computer program is read and executed by a processor, the method provided in the foregoing embodiment is implemented, and the same technical effect can be achieved, and in order to avoid repetition, details are not repeated here.

Although the present invention is disclosed above, the present invention is not limited thereto. Various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

The functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.

Finally, it should also be noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. The compressor oil amount control device and the air conditioner disclosed by the embodiment correspond to the oil return control method disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the method part for description.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.