Compressor oil level control method, system and air conditioner

Abstract

The application discloses a kind of compressor oil level control method, system and air conditioner, wherein the method comprises: when judging that compressor is running in preset operation interval, whether current operating frequency is in the normal operating frequency range that satisfies that compressor oil level is in safe position;If yes, keep the current operating frequency of compressor, otherwise, detect the running time of compressor at the current operating frequency, and when the running time is greater than or equal to the threshold value, adjust the operating frequency of the compressor according to the predetermined strategy until the compressor oil level is raised to the safe position, which can solve the problem of lack of oil in existing compressors without increasing oil separator in air conditioning system.

Description

Technical Field

[0001] This invention relates to the field of compressor oil level control technology, and in particular to a compressor oil level control method, system and air conditioner. Background Technology

[0002] The compressor is a crucial component of an air conditioner, accounting for a significant portion of its overall cost. To reduce the overall cost of air conditioners, small-displacement, high-speed compressors have become increasingly popular due to their lower cost. However, due to limitations in existing compressor design, a common and insurmountable problem exists: as the compressor's operating speed increases, its oil discharge rate gradually increases. After exceeding a certain threshold in the air conditioning system, the compressor's oil discharge rate may exceed its oil intake rate. At this point, the oil level in the compressor's oil sump gradually decreases until it reaches its lowest point.

[0003] In this situation, prolonged operation can lead to poor compressor lubrication, negatively impacting compressor and overall system reliability. To address this, existing technology involves adding an oil separator to the air conditioning system. This separator returns most of the lubricating oil discharged from the exhaust port directly to the compressor, overcoming the compressor's high oil discharge rate.

[0004] However, this method requires the addition of an oil separator and corresponding pipelines, which will increase the cost of the whole machine. It is a compromise solution. Furthermore, due to the limited efficiency of the oil separator, the oil return volume is always less than the oil discharge volume, and it cannot guarantee reliable lubrication of the compressor at high speeds.

[0005] Regarding the aforementioned technologies, the compressor requires an additional oil separator for oil return, but the oil return effect is still poor, leading to the potential for oil shortage. There is currently no effective solution to this technical problem. Summary of the Invention

[0006] The purpose of this invention is to overcome the above-mentioned technical deficiencies and provide a compressor oil level control method, system and air conditioner, which solves the problem of oil shortage in existing compressors without adding an oil separator to the air conditioning system.

[0007] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution:

[0008] According to one aspect of the present invention, a compressor oil level control method is provided, comprising:

[0009] When the compressor is operating within a preset operating range, determine whether the current operating frequency is within the normal operating frequency range that ensures the compressor oil level is at a safe position.

[0010] If so, maintain the compressor's current operating frequency; otherwise, detect the compressor's operating time at the current operating frequency, and if the operating time is greater than or equal to a threshold, adjust the compressor's operating frequency according to a predetermined strategy until the compressor oil level is raised to a safe position.

[0011] Optionally, the preset operating range includes: a high-temperature and high-pressure range where the compressor's system pressure is greater than a first pressure threshold and the exhaust temperature is greater than a temperature threshold;

[0012] The determination of whether the current operating frequency is within the normal operating frequency range that ensures the compressor oil level is at a safe position when the compressor is operating within the preset operating range specifically involves:

[0013] In the high temperature and high pressure range, if the current operating frequency is greater than or equal to the first frequency threshold, it is determined that the current operating frequency exceeds the normal operating frequency range that satisfies the requirement that the compressor oil level is in a safe position.

[0014] Optionally, adjusting the compressor's operating frequency according to a predetermined strategy until the compressor oil level reaches a safe position specifically involves:

[0015] The compressor's operating frequency is controlled to decrease to a first preset frequency, and it operates at the first preset frequency for a first preset time; wherein the first preset frequency is within the normal operating frequency range under the high temperature and high pressure range.

[0016] Optionally, the preset operating range includes: a high-temperature and sub-high-pressure range in which the system pressure of the compressor is less than or equal to a first pressure threshold and greater than a second pressure threshold, and the exhaust temperature is higher than a temperature threshold.

[0017] The determination of whether the current operating frequency is within the normal operating frequency range that ensures the compressor oil level is at a safe position when the compressor is operating within the preset operating range specifically involves:

[0018] In the high temperature and low pressure range, if the current operating frequency is greater than or equal to the first frequency threshold, it is determined that the current operating frequency exceeds the normal operating frequency range that satisfies the requirement that the compressor oil level is in a safe position.

[0019] Optionally, adjusting the compressor's operating frequency according to a predetermined strategy until the compressor oil level reaches a safe position specifically involves:

[0020] The compressor's operating frequency is controlled to decrease to a first preset frequency, and then operated at the first preset frequency for a second preset time; wherein the first preset frequency is within the normal operating frequency range under the high temperature and sub-high pressure range.

[0021] Optionally, the preset operating range further includes: an atmospheric pressure range in which the system pressure of the compressor is less than or equal to the second pressure threshold and greater than the third pressure threshold;

[0022] The determination of whether the current operating frequency is within the normal operating frequency range that ensures the compressor oil level is at a safe position when the compressor is operating within the preset operating range specifically involves:

[0023] In the atmospheric pressure range, if the current operating frequency is less than or equal to the second frequency threshold, it is determined that the current operating frequency exceeds the normal operating frequency range that satisfies the requirement that the compressor oil level is in a safe position.

[0024] Optionally, adjusting the compressor's operating frequency according to a predetermined strategy until the compressor oil level reaches a safe position specifically involves:

[0025] The compressor's operating frequency is controlled to increase to a second preset frequency, and then operated at the second preset frequency for a third preset time; wherein the second preset frequency is within the normal operating frequency range under the normal pressure range.

[0026] Optionally, the preset operating range further includes: a low-pressure range where the system pressure of the compressor is less than or equal to a third pressure threshold and greater than a fourth pressure threshold;

[0027] The determination of whether the current operating frequency is within the normal operating frequency range that ensures the compressor oil level is at a safe position when the compressor is operating within the preset operating range specifically involves:

[0028] In the low-pressure range, if the current operating frequency is less than or equal to the third frequency threshold, it is determined that the current operating frequency exceeds the normal operating frequency range that satisfies the requirement that the compressor oil level is in a safe position.

[0029] Optionally, adjusting the compressor's operating frequency according to a predetermined strategy until the compressor oil level reaches a safe position specifically involves:

[0030] The compressor's operating frequency is controlled to increase to a second preset frequency, and then operated at the second preset frequency for a fourth preset time; wherein the second preset frequency is within the normal operating frequency range under the low-pressure range.

[0031] Optionally, the preset operating range further includes: a high pressure ratio range where the ratio of the compressor's system high pressure to its system low pressure is greater than a predetermined ratio;

[0032] The method further includes: controlling the compressor to stop running, and then controlling the compressor to restart after a predetermined time has elapsed since the compressor stopped running.

[0033] According to another aspect of the present invention, a compressor oil level control system is provided, comprising: an operating frequency determination unit and an operating frequency control unit;

[0034] The operating frequency determination unit is used to determine whether the current operating frequency is within the normal operating frequency range that ensures the compressor oil level is in a safe position when the compressor is operating in a preset operating range.

[0035] If so, the operating frequency control unit maintains the compressor's current operating frequency; otherwise, the operating frequency control unit detects the compressor's operating time at the current operating frequency, and when the operating time is greater than or equal to a threshold, adjusts the compressor's operating frequency according to a predetermined strategy until the compressor oil level is raised to a safe position.

[0036] According to another aspect of the present invention, an air conditioner is also provided, comprising a controller and a compressor, the controller being configured to perform the steps in the above-described method to control the oil level of the compressor.

[0037] The present invention provides a compressor oil level control method, system, and air conditioner that does not require an additional oil separator. Instead, it determines whether the compressor is within a preset operating frequency range that meets the safe oil level requirement. If it is determined to be outside the normal operating frequency range, the compressor operating frequency is adjusted to bring the oil level back to a safe position. The entire oil level control process does not require an oil separator and is achieved solely through a control strategy. This can solve the problem of oil shortage in existing compressors without the need for an additional oil separator in the air conditioning system. Attached Figure Description

[0038] Figure 1 A schematic flowchart of a compressor oil level control method provided in an embodiment of the present invention;

[0039] Figure 2 This is a schematic diagram of an air conditioning system structure to which a compressor oil level control method is applicable, provided in an embodiment of the present invention.

[0040] Figure 3 This is a diagram showing the relationship between preset intervals in a compressor oil level control method provided by an embodiment of the present invention.

[0041] Figure 4 This is a schematic diagram of the structure of a compressor oil level control device provided in an embodiment of the present invention;

[0042] Figure 5 This is a schematic diagram of the structure of an air conditioner provided in an embodiment of the present invention. Detailed Implementation

[0043] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0044] In related technologies, compressors require the addition of an oil separator for oil return, but the oil return effect is still unsatisfactory, leading to the potential for oil shortage. Currently, there is no effective solution.

[0045] To address the aforementioned problems, this invention proposes a compressor oil level control method, system, and air conditioner, which solves the oil shortage problem of existing compressors without adding an additional oil separator to the air conditioning system. A detailed description follows.

[0046] According to an embodiment of the present invention, a compressor oil level control method is provided, comprising the following steps:

[0047] S101, determine whether the current operating frequency is within the normal operating frequency range that ensures the compressor oil level is in a safe position when the compressor is operating in the preset operating range;

[0048] S103, if yes, maintain the current operating frequency of the compressor; otherwise, detect the operating time of the compressor at the current operating frequency, and if the operating time is greater than or equal to a threshold, adjust the operating frequency of the compressor according to a predetermined strategy until the compressor oil level is raised to a safe position.

[0049] In step S101, the preset operating range can be set to multiple ranges according to the system pressure and / or exhaust temperature of the compressor. Under different ranges, the normal operating frequency range that can satisfy the compressor oil level to be in a safe position is different.

[0050] For example, it can be preset in the following way:

[0051] For the range where the compressor's system pressure is greater than the first pressure threshold and the exhaust temperature is higher than the temperature threshold, this range is set as the high temperature and high pressure range.

[0052] Furthermore, the range in which the compressor's system pressure is less than or equal to the first pressure threshold and greater than the second pressure threshold, and the exhaust temperature is higher than the temperature threshold, is defined as a high-temperature, sub-high-pressure range.

[0053] Furthermore, the range where the system pressure of the compressor is less than or equal to the second pressure threshold and greater than the third pressure threshold is set as the normal pressure range.

[0054] Furthermore, the range where the compressor's system pressure is less than or equal to the third pressure threshold and greater than the fourth pressure threshold is set as the low-pressure range.

[0055] As an example, in the above embodiment, the temperature threshold is set to 100℃, and the pressure thresholds can be expressed in terms of pressure. For example, the first pressure threshold can be set to 3.8 MPa, the second pressure threshold to 3.0 MPa, the third pressure threshold to 2.5 MPa, and the fourth pressure threshold to 1.1 MPa. The compressor system pressure at this time is the system high pressure, denoted as P. H Therefore, the specific pressure and temperature parameters for each of the above intervals are as follows:

[0056] A: High temperature and high pressure range (exhaust temperature above 100℃, P) H >3.8 MPa);

[0057] B: High temperature and sub-high pressure range (exhaust temperature above 100℃, 3.0 < P) H ≤3.8Mpa);

[0058] C: Normal pressure range (2.5 < P) H ≤3.0Mpa);

[0059] D: Low pressure range (1.1 < P) H ≤2.5Mpa).

[0060] Furthermore, in some embodiments, a high pressure ratio range can be set, in which the ratio of the system high pressure to the system low pressure of the compressor is greater than a predetermined ratio. For example, in this embodiment, a high pressure ratio range E is also set: (P H / P L >8). Among them, P H and P L These represent the system high pressure and system low pressure of the compressor, respectively.

[0061] By detecting the ambient temperature, exhaust temperature, and system pressure (obtained through temperature conversion or directly from sensors), it can be determined which specific operating range the compressor is currently in.

[0062] The calculation methods for the compressor's system high and low pressures are existing technologies and not improvements of this invention; they are only briefly described here. In existing technologies, under cooling mode operation, the system high pressure is generally considered to be a parameter related to the outdoor condenser pipe temperature and the outdoor ambient temperature, and can be estimated using these two parameter values. Under heating mode operation, the system high pressure is generally considered to be a parameter related to the indoor evaporator pipe temperature and the indoor ambient temperature, and can be estimated using these two parameter values. Of course, in some technical solutions, the system high and low pressures can also be directly detected by high and low pressure sensors, without the need for temperature conversion.

[0063] Taking a single-split inverter heat pump air conditioner as an example, combined with Figure 2 The air conditioning system includes at least a compressor, a four-way valve, a condenser, a throttling device (such as an electronic expansion valve), an evaporator, an indoor fan, and an outdoor fan. To meet the requirements for air conditioning system parameter detection and control, the system also includes indoor and outdoor return air temperature sensors, an outdoor heat exchanger temperature sensor, an indoor heat exchanger pipe temperature sensor, and a compressor exhaust temperature sensor (not shown in the figure), which can acquire evaporator pipe temperature, outdoor ambient temperature, indoor ambient temperature, exhaust temperature, etc.

[0064] In cooling mode, the system high pressure is generally considered to be related to the outdoor condenser tube temperature T. 外管 and outdoor ambient temperature T 外环 The relevant parameters can be estimated using these two parameter values, denoted as P. 冷H P 冷H =f1(T 外管 ,T 外环 The system low pressure is related to the evaporator tube temperature T. 内管 and indoor ambient temperature T 内环 The relevant parameters can be estimated using these two parameter values. Let P be the value of P. 冷L P 冷L =f2(T 内管 ,T 内环 ).

[0065] Under heating mode operation, the system high pressure is generally considered to be related to the indoor evaporator tube temperature T. 内管 and indoor ambient temperature T 内环 The relevant parameters can be estimated using these two parameter values, denoted as P. 热H P 热H =f3(T 内管 ,T 内环 The system low pressure is related to the evaporator tube temperature T. 外管 and indoor ambient temperature T 外环 The relevant parameters can be estimated using these two parameter values, denoted as P. 热L P 热L =f4(T外管 ,T 外环 ).

[0066] Because the outdoor and indoor units have different heat exchanger sizes and airflow rates, the functions used to estimate the corresponding pressures differ, and the functions also differ between cooling and heating modes. As mentioned earlier, the specific function calculations are not within the scope of this invention and will not be described in detail.

[0067] Below, we will introduce the corresponding operating frequency determination steps and control strategies based on different preset operating ranges.

[0068] In the high temperature and high pressure range, step S101 specifically includes: if the current operating frequency is greater than or equal to the first frequency threshold, it is determined that it exceeds the normal operating frequency range;

[0069] Accordingly, in step S103, adjusting the operating frequency of the compressor according to a predetermined strategy until the compressor oil level is raised to a safe position includes:

[0070] The compressor's operating frequency is controlled to decrease to a first preset frequency, and it operates at the first preset frequency for a first preset time; wherein the first preset frequency is within the normal operating frequency range under the high temperature and high pressure range.

[0071] In high-temperature and high-pressure environments, the operating conditions are harsh, and compressor frequencies are typically high. Under normal conditions, higher compressor frequencies result in higher speeds, larger oil discharge volumes, and a greater likelihood of low oil levels. Therefore, when the current operating frequency exceeds a first preset frequency, it needs to be forcibly reduced. For example, in high-temperature and high-pressure environments, the upper limit of the normal operating frequency that ensures a safe oil level can be used as a benchmark, minus a predetermined frequency value. This subtracted frequency value becomes the adjusted operating frequency. Since the compressor operates below the upper limit of the normal operating frequency, the oil return volume is greater than the oil discharge volume, causing the oil level to gradually rise and return to a safe level. For instance, assuming the current operating frequency is higher than 70Hz, and the upper limit of the normal operating frequency is also 70Hz (i.e., the first frequency threshold), the frequency can be reduced to 60Hz (i.e., the upper limit minus 10Hz). Running at this frequency for a first preset time, such as 5 minutes, ensures that the compressor continues to run for at least 2 minutes after the oil level returns to a safe level, and then the compressor operation is controlled according to the normal frequency.

[0072] In the high temperature and low pressure range, step S101 specifically includes: if the current operating frequency is greater than or equal to the first frequency threshold, it is determined that it exceeds the normal operating frequency range;

[0073] Accordingly, step S103 specifically includes:

[0074] The compressor's operating frequency is controlled to decrease to the first preset frequency, and it operates at the first preset frequency for a second preset time; wherein the first preset frequency is also within the normal operating frequency range under the high temperature and low pressure range; in some embodiments, the second preset time is less than the first preset time.

[0075] In the high-temperature and low-pressure range, although the operating conditions are still relatively harsh, the system pressure is lower than that in the high-temperature and high-pressure range. Therefore, the control strategy can be basically the same as that in the high-temperature and high-pressure range. However, in some embodiments, the difference from the high-temperature and high-pressure range is that the running time at this time, i.e. the second preset time, can be slightly shorter than the first preset time in the high-temperature and high-pressure range. This is because the pressure is not very high at this time, and at the same operating frequency, it can recover to the safe oil level more quickly.

[0076] For example, assuming the current operating frequency is higher than 70Hz, and the upper limit of the normal operating frequency is also 70Hz (which is the same as the high temperature and high pressure range, and is also the first frequency threshold), the frequency can be reduced to 60Hz (that is, the upper limit of this range minus 10Hz). When running at this frequency for a second preset time, such as 3 minutes, it can be ensured that the compressor will continue to run for at least 2 minutes after the oil level returns to the safe oil level, and then the operation of the compressor can be controlled according to the normal frequency.

[0077] In the normal pressure range, step S101 specifically includes: if the current operating frequency is less than or equal to the second frequency threshold, it is determined that it exceeds the normal operating frequency range;

[0078] Accordingly, step S103 includes: controlling the operating frequency of the compressor to increase to a second preset frequency, and operating at the second preset frequency for a third preset time; wherein the second preset frequency is within the normal operating frequency range under the normal pressure range.

[0079] Unlike the judgment logic for the high-temperature and high-pressure zone and the high-temperature and sub-high-pressure zone mentioned above, in the normal pressure zone, the judgment condition for exceeding the normal frequency is usually not based on exceeding a certain threshold. Instead, it is judged whether the current operating frequency is lower than a second frequency threshold. This is because, although the oil discharge volume of a normal compressor is small at low frequencies, the lubricating oil needs to flow with the refrigerant. When the frequency is too low, the refrigerant flow rate is small and the refrigerant flow speed is slow, which will also cause the discharged lubricating oil to not be carried back to the compressor in time with the suction. On the other hand, due to the special characteristics of some compressors, some have a particularly high oil discharge rate at high frequencies. The oil drawn back is immediately discharged, resulting in insufficient oil level in the compressor oil sump. Therefore, there will be a situation where the compressor oil level is insufficient at both low and high frequencies. The normal pressure zone set in this embodiment is aimed at the problem of insufficient compressor oil level at low frequencies. That is, when the current operating frequency is less than or equal to the second frequency threshold, it is determined to be outside the normal operating frequency range.

[0080] If the compressor's operating frequency is determined to be outside the normal operating frequency range, the compressor's operating frequency is increased to the normal operating frequency range. At this time, due to the increased frequency, the refrigerant flow rate and speed are accelerated, allowing the discharged lubricating oil to be promptly carried back to the compressor with the suction air, gradually raising the oil level to a safe position. The second preset frequency can be set to the upper limit of the normal operating frequency in the high-temperature, sub-high-pressure range. Operating at this upper limit allows for a faster return of the oil level to a safe value, while also preventing the adjusted operating frequency from being too high and thus lowering the oil level.

[0081] For example, if the compressor operating frequency is below 50Hz (i.e., the second frequency threshold), when the cumulative time is met, the compressor frequency is forced to rise to 70Hz (the upper limit of the normal operating frequency range in the high temperature and sub-high pressure range) and run for 3 minutes. Then, according to normal frequency control, this control strategy can ensure that the compressor oil sump runs at a safe oil level for more than 2 minutes during the frequency rise time.

[0082] In the low-voltage range, step S101 specifically includes: if the current operating frequency is less than or equal to the third frequency threshold, it is determined that it exceeds the normal operating frequency range;

[0083] Accordingly, step S103 specifically includes:

[0084] The compressor's operating frequency is controlled to increase to the second preset frequency, and then operated at the second preset frequency for a fourth preset time; wherein the second preset frequency is also within the normal operating frequency range under the low-pressure range;

[0085] In some embodiments, the third preset time is less than the fourth preset time.

[0086] In the low-pressure range, similar to the atmospheric pressure range, when the compressor operates at a low frequency, the refrigerant flow is small and the refrigerant flow speed is slow. This also means that the discharged lubricating oil cannot be carried back to the compressor with the suction in time. Therefore, it is necessary to increase the operating frequency to control the compressor oil level to rise to a safe position. However, in some embodiments, unlike the atmospheric pressure range, the low-pressure range corresponds to a lower system pressure. In cooling mode, this corresponds to low-temperature cooling operation when the outdoor ambient temperature is low, resulting in more severe compressor operating conditions. To improve compressor reliability, the oil return operation time is correspondingly increased, even if the fourth preset time is longer than the third preset time. Similarly, in heating mode, the indoor ambient temperature is low, also resulting in more severe operating conditions.

[0087] Similarly, the second preset frequency can also be the upper limit of the operating frequency range that can keep the compressor oil level at a safe position under high temperature and low pressure conditions, so as to achieve a similar effect to the normal pressure range, which will not be elaborated here.

[0088] For example, if the compressor operating frequency is below 60Hz (i.e., the third frequency threshold) and the system high pressure is low, once the cumulative time is met, the compressor frequency is forced to rise to 70Hz (the upper limit of the normal operating frequency range in the high-temperature, sub-high-pressure range) for 5 minutes, and then controlled according to the normal frequency. This control strategy can ensure that the compressor oil sump operates at a safe oil level for more than 2 minutes during the frequency rise time.

[0089] Furthermore, in the high pressure ratio range, since the operating conditions are at their worst, the method also includes: controlling the compressor to stop running, after a predetermined time of shutdown, fully returning oil to raise the oil level to a safe position, and then controlling the compressor to restart.

[0090] This embodiment pre-sets the compressor's operating range according to the compressor's system pressure and / or exhaust temperature, and determines whether the compressor is within the normal operating frequency range that meets the safe oil level requirement within the corresponding operating range. If it is determined that the operating frequency range is exceeded, the compressor's operating frequency is adjusted to bring its oil level back to a safe position. The entire oil level control process does not require an oil separator and is achieved simply by using a control strategy. This can solve the problem of oil shortage in existing compressors without adding an extra oil separator to the air conditioning system.

[0091] When setting the first, second, and third frequency thresholds mentioned above, as well as the adjusted first and second preset frequencies and the corresponding preset running time, these can be reasonably set based on the compressor characteristics and air conditioning system test data. Below, based on the five intervals A, B, C, D, and E mentioned above (the relationship between each interval and high and low pressure is as follows...),... Figure 3As shown in the figure, an exemplary method for dividing the compressor operating frequency and corresponding operating range is given, but it should be understood that this does not constitute a limitation on the scope of protection of the present invention.

[0092] Table 1. Correspondence between compressor operating frequency and operating range.

[0093]

[0094] Table 1 divides the compressor's operating frequency into different intervals. In this example, frequencies below 50Hz form one interval, frequencies above 100Hz form another, and other frequencies are divided into intervals of 10Hz each. There are no restrictions on the number of intervals or frequency values; the actual frequency should be determined based on the compressor's characteristics and the air conditioning system's testing. This table is for illustrative purposes only.

[0095] The cumulative time t is the cumulative continuous time of the compressor in each frequency range and the corresponding operating range of the system. It is expressed in minutes.

[0096] The intervals marked with " / " in Table 1 can be considered as the compressor operating within the normal range with a safe oil level. The compressor's operating time is not recorded, and oil level control is not required. The meanings of A, B, C, D, and E are the same as above and will not be explained again.

[0097] At this time, the compressor oil level control methods include:

[0098] Scenario 1: Running time t in interval A A Greater than the preset value t A0

[0099] At this point, the compressor's operating frequency is higher than 70Hz. Once the accumulated time is met, the compressor frequency is forced to decrease to 60Hz (10Hz less than the upper limit frequency of interval A where time is not counted) for 5 minutes, and then controlled according to the normal frequency. This time can also be other values, depending on the specific compressor and air conditioning system, ensuring that the compressor oil sump remains at a safe oil level for more than 2 minutes during the frequency reduction period.

[0100] Scenario 2: Running time t in interval B B Greater than the preset value t B0

[0101] At this point, the compressor's operating frequency is higher than 70Hz, but the system high pressure is not high. When the accumulated time is met, the compressor frequency is forced to decrease to 60Hz (10Hz less than the upper limit frequency of the B range where time is not counted) for 3 minutes, and then controlled according to the normal frequency. This time can also be other values, which need to be confirmed according to different compressors and different air conditioning systems, ensuring that the compressor oil sump stays at the safe oil level for more than 2 minutes during the frequency reduction period. Generally, the forced running time in the B range is set to be less than that in the A range.

[0102] Scenario 3: Running time t in interval C C Greater than the preset value t C0

[0103] At this point, the compressor's operating frequency is below 50Hz. Once the cumulative time is met, the compressor frequency is forced to rise to 70Hz (the upper limit frequency for which time is not counted in range B) and run for 3 minutes, then controlled according to the normal frequency. This time can also be other values, depending on the specific compressor and air conditioning system, ensuring that the compressor oil sump remains at a safe oil level for more than 2 minutes during the frequency increase period.

[0104] Scenario 4: Running time t in interval D D Greater than the preset value t D0

[0105] At this point, the compressor operating frequency is below 60Hz, and the system high pressure is low. Once the cumulative time is met, the compressor frequency is forced to rise to 70Hz (the upper limit frequency for which time is not counted in section B) and run for 5 minutes. This time can then be controlled according to the normal frequency, or it can be other values. The specific value needs to be confirmed based on different compressors and different air conditioning systems, ensuring that the compressor oil sump stays at the safe oil level for more than 2 minutes during the frequency increase period. Generally, the forced running time in section C is set to be less than that in section D.

[0106] Scenario 5: Running time t in interval E E Greater than the preset value t E0

[0107] When the cumulative time is met, the compressor is forced to stop for 3 minutes, and then controlled according to the normal frequency.

[0108] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods according to the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk), and includes several instructions to cause a terminal device (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in the various embodiments of this application.

[0109] Example 2

[0110] According to an embodiment of the present invention, a compressor oil level control system is provided, combined with Figure 4 It includes: an operating frequency determination unit 21 and an operating frequency control unit 23. Wherein:

[0111] The operating frequency determination unit 21 is used to determine whether the current operating frequency is within the normal operating frequency range that satisfies the requirement that the compressor oil level is in a safe position when the compressor is operating in a preset operating range.

[0112] If so, the operating frequency control unit 23 maintains the current operating frequency of the compressor; otherwise, the operating frequency control unit 23 detects the operating time of the compressor at the current operating frequency, and when the operating time is greater than or equal to a threshold, adjusts the operating frequency of the compressor according to a predetermined strategy until the compressor oil level is raised to a safe position.

[0113] Optionally, the preset operating range includes: a high-temperature and high-pressure range where the compressor's system pressure is greater than a first pressure threshold and the exhaust temperature is greater than a temperature threshold;

[0114] The operating frequency determination unit 21 is specifically used for:

[0115] In the high temperature and high pressure range, if the current operating frequency is greater than or equal to the first frequency threshold, it is determined that the current operating frequency exceeds the normal operating frequency range that satisfies the requirement that the compressor oil level is in a safe position.

[0116] Optionally, the operating frequency control unit 23 is specifically used for:

[0117] The compressor's operating frequency is controlled to decrease to a first preset frequency, and it operates at the first preset frequency for a first preset time; wherein the first preset frequency is within the normal operating frequency range under the high temperature and high pressure range.

[0118] Optionally, the preset operating range includes: a high-temperature and sub-high-pressure range in which the system pressure of the compressor is less than or equal to a first pressure threshold and greater than a second pressure threshold, and the exhaust temperature is higher than a temperature threshold.

[0119] The operating frequency determination unit 21 is specifically used for:

[0120] In the high temperature and low pressure range, if the current operating frequency is greater than or equal to the first frequency threshold, it is determined that the current operating frequency exceeds the normal operating frequency range that satisfies the requirement that the compressor oil level is in a safe position.

[0121] Optionally, the operating frequency control unit 23 is specifically used for:

[0122] The compressor's operating frequency is controlled to decrease to a first preset frequency, and then operated at the first preset frequency for a second preset time; wherein the first preset frequency is within the normal operating frequency range under the high temperature and sub-high pressure range.

[0123] Optionally, the preset operating range further includes: an atmospheric pressure range in which the system pressure of the compressor is less than or equal to the second pressure threshold and greater than the third pressure threshold;

[0124] The operating frequency determination unit 21 is specifically used for:

[0125] In the atmospheric pressure range, if the current operating frequency is less than or equal to the second frequency threshold, it is determined that the current operating frequency exceeds the normal operating frequency range that satisfies the requirement that the compressor oil level is in a safe position.

[0126] Optionally, the operating frequency control unit 23 is specifically used for:

[0127] The compressor's operating frequency is controlled to increase to a second preset frequency, and then operated at the second preset frequency for a third preset time; wherein the second preset frequency is within the normal operating frequency range under the normal pressure range.

[0128] Optionally, the preset operating range further includes: a low-pressure range where the system pressure of the compressor is less than or equal to a third pressure threshold and greater than a fourth pressure threshold;

[0129] The operating frequency determination unit 21 is specifically used for:

[0130] In the low-pressure range, if the current operating frequency is less than or equal to the third frequency threshold, it is determined that the current operating frequency exceeds the normal operating frequency range that satisfies the requirement that the compressor oil level is in a safe position.

[0131] Optionally, the operating frequency control unit 23 is specifically used for:

[0132] The compressor's operating frequency is controlled to increase to a second preset frequency, and then operated at the second preset frequency for a fourth preset time; wherein the second preset frequency is within the normal operating frequency range under the low-pressure range.

[0133] Optionally, the preset operating range further includes a high pressure ratio range where the ratio of the system high pressure to the system low pressure of the compressor is greater than a predetermined ratio. The system further includes a forced stop unit for controlling the compressor to stop running and then controlling the compressor to restart after a predetermined time of stopping.

[0134] Optionally, specific examples in this embodiment can refer to the examples described in the above embodiments, and will not be repeated here.

[0135] It should be noted that the examples and application scenarios implemented by the above modules and corresponding steps are the same, but are not limited to the content disclosed in the above embodiments. It should also be noted that the above modules, as part of the device, can run in a corresponding hardware environment, and can be implemented through software or hardware, wherein the hardware environment includes a network environment.

[0136] Figure 5 This is a structural block diagram of an air conditioner according to an embodiment of this application, such as... Figure 5 As shown, the air conditioner may include a compressor and a controller: the controller includes one or more (only one is shown) processors 101 and memory 103.

[0137] The memory 103 can be used to store software programs and modules, such as the program instructions / modules corresponding to the methods and apparatus in this embodiment. The processor 101 executes various functional applications and data processing by running the software programs and modules stored in the memory 103, thereby implementing the above-described methods. The memory 103 may include high-speed random access memory, and may also include non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some instances, the memory 103 may further include memory remotely located relative to the processor 101, and these remote memories can be connected to the terminal via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0138] Specifically, memory 103 is used to store application programs.

[0139] The processor 101 can execute the following steps by calling the application stored in the memory 103: determining whether the current operating frequency is within the normal operating frequency range that satisfies the requirement that the compressor oil level is at a safe position when the compressor is operating in a preset operating range; if so, maintaining the current operating frequency of the compressor; otherwise, detecting the operating time of the compressor at the current operating frequency, and adjusting the operating frequency of the compressor according to a predetermined strategy when the operating time is greater than or equal to a threshold, until the compressor oil level is raised to a safe position.

[0140] Optionally, specific examples in this embodiment can refer to the examples described in the above embodiments, and will not be repeated here.

[0141] In the above embodiments of this application, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0142] In the embodiments provided in this application, the described device embodiments are merely illustrative. For example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual couplings, direct couplings, or communication connections may be through some interfaces, indirect couplings, or communication connections between units or modules, and may be electrical or other forms.

[0143] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0144] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0145] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A compressor oil level control method, characterized in that, include: When the compressor is operating within a preset operating range, determine whether the current operating frequency is within the normal operating frequency range that ensures the compressor oil level is at a safe position. If so, maintain the compressor's current operating frequency; otherwise, detect the compressor's operating time at the current operating frequency, and if the operating time is greater than or equal to a threshold, adjust the compressor's operating frequency according to a predetermined strategy until the compressor oil level is raised to a safe position. For the range where the compressor's system pressure is greater than the first pressure threshold and the exhaust temperature is higher than the temperature threshold, this range is set as the high temperature and high pressure range. For the compressor, the range where the system pressure is less than or equal to the first pressure threshold and greater than the second pressure threshold, and the exhaust temperature is higher than the temperature threshold, is set as the high temperature and low pressure range. For the compressor system pressure range that is less than or equal to the second pressure threshold and greater than the third pressure threshold, it is set as the normal pressure range. For the compressor system pressure range that is less than or equal to the third pressure threshold and greater than the fourth pressure threshold, it is set as the low pressure range. In the high temperature and high pressure range, if the current operating frequency is greater than or equal to the first frequency threshold, it is determined that the current operating frequency exceeds the normal operating frequency range that satisfies the requirement that the compressor oil level is in a safe position; the operating frequency of the compressor is adjusted according to a predetermined strategy until the compressor oil level is raised to a safe position, specifically: the operating frequency of the compressor is controlled to be reduced to a first preset frequency, and the compressor is operated at the first preset frequency for a first preset time; wherein, the first preset frequency is within the normal operating frequency range under the high temperature and high pressure range; In the high-temperature, sub-high-pressure range, if the current operating frequency is greater than or equal to the first frequency threshold, it is determined that the current operating frequency exceeds the normal operating frequency range that satisfies the requirement for the compressor oil level to be at a safe position; the operating frequency of the compressor is adjusted according to a predetermined strategy until the compressor oil level is raised to a safe position, specifically: the operating frequency of the compressor is controlled to decrease to the first preset frequency, and the compressor is operated at the first preset frequency for a second preset time; wherein, the first preset frequency is within the normal operating frequency range under the high-temperature, sub-high-pressure range, and the second preset time is less than the first preset time; In the atmospheric pressure range, if the current operating frequency is less than or equal to the second frequency threshold, it is determined that the current operating frequency exceeds the normal operating frequency range that satisfies the requirement that the compressor oil level is in a safe position; the operating frequency of the compressor is adjusted according to a predetermined strategy until the compressor oil level is raised to a safe position, specifically: the operating frequency of the compressor is controlled to rise to a second preset frequency, and the compressor is operated at the second preset frequency for a third preset time; wherein, the second preset frequency is within the normal operating frequency range under the atmospheric pressure range; In the low-pressure range, if the current operating frequency is less than or equal to the third frequency threshold, it is determined that the current operating frequency exceeds the normal operating frequency range that satisfies the requirement for the compressor oil level to be in a safe position; the operating frequency of the compressor is adjusted according to a predetermined strategy until the compressor oil level is raised to a safe position, specifically: the operating frequency of the compressor is controlled to rise to the second preset frequency, and the compressor is operated at the second preset frequency for a fourth preset time; wherein, the second preset frequency is within the normal operating frequency range under the low-pressure range, and the third preset time is less than the fourth preset time.

2. The compressor oil level control method according to claim 1, characterized in that, The preset operating range also includes: a high pressure ratio range in which the ratio of the compressor's system high pressure to its system low pressure is greater than a predetermined ratio; The method further includes: if the pressure ratio range is within the range, controlling the compressor to stop running, and then controlling the compressor to restart after a predetermined time has elapsed since the stop running.

3. A compressor oil level control system, characterized in that, The method applicable to any one of claims 1-2 includes: an operating frequency determination unit and an operating frequency control unit; The operating frequency determination unit is used to determine whether the current operating frequency is within the normal operating frequency range that ensures the compressor oil level is in a safe position when the compressor is operating in a preset operating range. If so, the operating frequency control unit maintains the compressor's current operating frequency; otherwise, the operating frequency control unit detects the compressor's operating time at the current operating frequency, and when the operating time is greater than or equal to a threshold, adjusts the compressor's operating frequency according to a predetermined strategy until the compressor oil level is raised to a safe position.

4. An air conditioner, comprising a controller and a compressor, the controller being configured to perform the steps of the method as described in any one of claims 1-2 to control the oil level of the compressor.

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