A control method and device of a heat pump unit, the heat pump unit and a storage medium

Abstract

The application discloses a kind of control method, device, heat pump unit and storage medium of heat pump unit, the method includes: after heat pump unit starts and runs first set time, the current oil level of compressor is obtained, the current oil level of oil storage device is obtained, and the current gas pressure of oil storage device is obtained;Combining the current oil level of compressor and the current oil level of oil storage device, the frequency of compressor and / or the opening and closing of first switch are controlled to realize the first control to the oil level of compressor;And / or, according to the current gas pressure of oil storage device, the opening and closing of second switch is controlled, and the opening and closing of air supplement switch is controlled to realize the second control to the oil level of compressor.The scheme, by the oil level and gas pressure of oil storage tank, and the oil level of compressor, accurately control the oil level of compressor, ensure that compressor runs smoothly and safely, improve the comfort experience of user.

Description

Technical Field

[0001] This invention belongs to the technical field of heat pump units, specifically relating to a control method, device, heat pump unit, and storage medium for a heat pump unit, and particularly to a control method, device, heat pump unit, and storage medium for a compressor oil return system of a heat pump unit. Background Technology

[0002] For heat pump units, the compressor, as the heart of the entire refrigeration system, requires a sufficient and appropriate lubricating oil level to ensure stable and safe operation. However, in some solutions, controlling the compressor oil level is quite difficult, making it impossible to guarantee stable and safe operation and affecting the user's comfort experience.

[0003] The above content is only used to help understand the technical solution of the present invention and does not represent an admission that the above content is prior art. Summary of the Invention

[0004] The purpose of this invention is to provide a control method, device, heat pump unit, and storage medium for a heat pump unit, in order to solve the problem that in related solutions, the oil level control of the compressor is difficult, which cannot guarantee the stable and safe operation of the compressor and affects the user's comfort experience. The invention achieves the effect of accurately controlling the oil level of the compressor based on the oil level and gas pressure of the oil tank and the oil level of the compressor, avoiding the compressor from running at the oil return frequency when the oil level in the machine body is insufficient, ensuring the stable and safe operation of the compressor, and improving the user's comfort experience.

[0005] This invention provides a control method for a heat pump unit, wherein the heat pump unit includes: a compressor, a condenser, an evaporator, an oil storage device, and an oil-gas separator; the exhaust port of the compressor, after passing through the oil-gas separator, is connected to the inlet of the condenser; the outlet of the evaporator is connected to the suction port of the compressor; a first bypass pipeline is led out from the oil return port of the oil storage device and connected to the pipeline where the suction port of the compressor is located; a second bypass pipeline is led out from the gas return port of the oil storage device and connected to the pipeline where the outlet of the evaporator is located; a third bypass pipeline is led out from the pipeline between the outlet of the oil-gas separator and the inlet of the condenser and connected to the gas replenishment port of the oil storage device; a first switch is provided on the first bypass pipeline, a second switch is provided on the second bypass pipeline, and a third switch is provided on the third bypass pipeline. A gas supply switch is installed on the bypass pipeline; the control method of the heat pump unit includes: after the heat pump unit is started and running for a first set time, acquiring the oil level monitoring data of the compressor and recording it as the current oil level of the compressor; acquiring the oil level monitoring data of the oil storage device and recording it as the current oil level of the oil storage device; and acquiring the gas pressure monitoring data of the oil storage device and recording it as the current gas pressure of the oil storage device; combining the current oil level of the compressor and the current oil level of the oil storage device, controlling the frequency of the compressor and / or the opening and closing of the first switch to achieve the first control of the oil level of the compressor; and / or, according to the current gas pressure of the oil storage device, controlling the opening and closing of the second switch and controlling the opening and closing of the gas supply switch to achieve the second control of the oil level of the compressor.

[0006] In some embodiments, the compressor frequency and / or the opening and closing of the first switch are controlled by combining the current oil level of the compressor and the current oil level of the oil storage device to achieve first control of the oil level of the compressor, including: determining whether the current oil level of the oil storage device is less than a preset lower limit of the oil level of the oil storage device; if it is determined that the current oil level of the oil storage device is less than the preset lower limit of the oil level of the oil storage device, then controlling the compressor to run at a preset oil return frequency of the compressor for a second preset time; determining whether the current oil level of the oil storage device is greater than a preset median oil level of the oil storage device; the preset median oil level of the oil storage device is greater than the preset lower limit of the oil level of the oil storage device; if it is determined that the current oil level of the oil storage device is not greater than the preset median oil level of the oil storage device, then returning to the previous state to continue controlling the compressor to run at the preset oil return frequency of the compressor for a second preset time.

[0007] In some embodiments, the compressor frequency and / or the opening and closing of the first switch are controlled in combination with the current oil level of the compressor and the current oil level of the oil storage device to achieve the first control of the oil level of the compressor. This further includes: if it is determined that the current oil level of the oil storage device is less than a preset lower limit for the oil level of the oil storage device, then determining whether the current oil level of the compressor is less than a preset lower limit for the oil level of the compressor; if it is determined that the current oil level of the compressor is less than the preset lower limit for the oil level of the compressor, then controlling the opening and closing of the first switch to allow the oil storage device to fill the compressor with oil.

[0008] In some embodiments, controlling the opening and closing of the first switch to allow the oil storage device to fill the compressor with oil includes: controlling the first switch to open so that the oil storage device fills the compressor with oil for a third preset time; determining whether the current oil level of the compressor is greater than a preset upper limit of the compressor oil level; the preset upper limit of the compressor oil level is greater than a preset lower limit of the compressor oil level; if it is determined that the current oil level of the compressor is not greater than the preset upper limit of the compressor oil level, then returning to control the first switch to open again so that the oil storage device fills the compressor with oil for a third preset time; if it is determined that the current oil level of the compressor is greater than the preset upper limit of the compressor oil level, then controlling the compressor to continue operating normally, returning after a fourth preset time, to continue determining whether the current oil level of the oil storage device is less than the preset lower limit of the oil storage device oil level.

[0009] In some embodiments, the compressor frequency and / or the opening and closing of the first switch are controlled in combination with the current oil level of the compressor and the current oil level of the oil storage device to achieve the first control of the oil level of the compressor. This further includes: if it is determined that the current oil level of the oil storage device is greater than a preset median oil level of the oil storage device, or if it is determined that the current oil level of the compressor is less than a preset lower oil level limit of the compressor, then it is determined whether the current oil level of the oil storage device is greater than a preset upper oil level limit of the oil storage device; the preset upper oil level limit of the oil storage device is greater than the preset median oil level of the oil storage device; if it is determined that the current oil level of the oil storage device is greater than the preset upper oil level limit of the oil storage device, then the opening and closing of the first switch is controlled so that the oil storage device fills the compressor with oil; if it is determined that the current oil level of the oil storage device is not greater than the preset upper oil level limit of the oil storage device, then the compressor is controlled to continue normal operation, returning after a fourth preset time, to continue determining whether the current oil level of the oil storage device is less than the preset lower oil level limit of the oil storage device.

[0010] In some embodiments, the opening and closing of the second switch and the opening and closing of the gas replenishment switch are controlled according to the current gas pressure of the oil storage device to achieve a second control of the oil level of the compressor, including: determining whether the current gas pressure of the oil storage device is greater than a preset upper pressure limit of the oil storage device; if it is determined that the current gas pressure of the oil storage device is greater than the preset upper pressure limit of the oil storage device, then controlling the second switch to open and controlling the gas replenishment switch to close, for a fifth preset time; determining whether the current gas pressure of the oil storage device is less than a preset median pressure of the oil storage device; The preset median pressure of the oil storage device is less than the preset upper limit pressure of the oil storage device. If it is determined that the current gas pressure of the oil storage device is less than the preset median pressure of the oil storage device, the second switch is controlled to close, and the gas replenishment switch is kept closed. Then, the process returns to continue determining that the current gas pressure of the oil storage device is greater than the preset upper limit pressure of the oil storage device. If it is determined that the current gas pressure of the oil storage device is not less than the preset median pressure of the oil storage device, the process returns to continue controlling the second switch to open and controlling the gas replenishment switch to close, for a fifth preset time.

[0011] In some embodiments, the opening and closing of the second switch and the opening and closing of the gas replenishment switch are controlled according to the current gas pressure of the oil storage device to achieve a second control of the oil level of the compressor. This further includes: if it is determined that the current gas pressure of the oil storage device is not greater than a preset upper pressure limit of the oil storage device, then determining whether the current gas pressure of the oil storage device is greater than a preset lower pressure limit of the oil storage device; the preset median pressure of the oil storage device is greater than the preset lower pressure limit of the oil storage device; if it is determined that the current gas pressure of the oil storage device is greater than the preset lower pressure limit of the oil storage device, then the second switch is controlled to close, and the gas replenishment switch is controlled to open, for a fifth preset time. The system determines whether the current gas pressure of the oil storage device is less than the preset median pressure of the oil storage device; the preset median pressure of the oil storage device is less than the preset upper limit pressure of the oil storage device; if the current gas pressure of the oil storage device is determined to be less than the preset median pressure of the oil storage device, the second switch is controlled to close, and the gas replenishment switch is kept closed, then the process returns to continue determining whether the current gas pressure of the oil storage device is greater than the preset upper limit pressure of the oil storage device; if the current gas pressure of the oil storage device is determined not to be less than the preset median pressure of the oil storage device, the process returns to continue controlling the second switch to close, and controlling the gas replenishment switch to open, for a fifth preset time.

[0012] In conjunction with the above method, another aspect of the present invention provides a control device for a heat pump unit, the heat pump unit comprising: a compressor, a condenser, an evaporator, an oil storage device, and an oil-gas separator; the exhaust port of the compressor, after passing through the oil-gas separator, is connected to the inlet of the condenser; the outlet of the evaporator is connected to the suction port of the compressor; a first bypass pipeline is led out from the oil return port of the oil storage device and connected to the pipeline where the suction port of the compressor is located; a second bypass pipeline is led out from the gas return port of the oil storage device and connected to the pipeline where the outlet of the evaporator is located; a third bypass pipeline is led out from the pipeline between the outlet of the oil-gas separator and the inlet of the condenser and connected to the gas replenishment port of the oil storage device; a first switch is provided on the first bypass pipeline, a second switch is provided on the second bypass pipeline, and a third bypass pipeline is provided on the third bypass pipeline. A gas replenishment switch is installed on the pipeline; the control device of the heat pump unit includes: an acquisition unit configured to acquire oil level monitoring data of the compressor, and record it as the current oil level of the compressor, after the heat pump unit is turned on and running for a first set time; acquire oil level monitoring data of the oil storage device, and record it as the current oil level of the oil storage device; and acquire gas pressure monitoring data of the oil storage device, and record it as the current gas pressure of the oil storage device; a control unit configured to combine the current oil level of the compressor and the current oil level of the oil storage device to control the frequency of the compressor and / or the opening and closing of the first switch to achieve first control of the oil level of the compressor; and / or, according to the current gas pressure of the oil storage device, control the opening and closing of the second switch and control the opening and closing of the gas replenishment switch to achieve second control of the oil level of the compressor.

[0013] In some embodiments, the control unit, in conjunction with the current oil level of the compressor and the current oil level of the oil storage device, controls the frequency of the compressor and / or the opening and closing of the first switch to achieve first control of the oil level of the compressor, including: determining whether the current oil level of the oil storage device is less than a preset lower limit of the oil level of the oil storage device; if it is determined that the current oil level of the oil storage device is less than the preset lower limit of the oil level of the oil storage device, then controlling the compressor to run at a preset oil return frequency of the compressor for a second preset time; determining whether the current oil level of the oil storage device is greater than a preset median oil level of the oil storage device; the preset median oil level of the oil storage device is greater than the preset lower limit of the oil level of the oil storage device; if it is determined that the current oil level of the oil storage device is not greater than the preset median oil level of the oil storage device, then returning to the previous state to continue controlling the compressor to run at the preset oil return frequency of the compressor for a second preset time.

[0014] In some embodiments, the control unit, in conjunction with the current oil level of the compressor and the current oil level of the oil storage device, controls the frequency of the compressor and / or the opening and closing of the first switch to achieve first control of the oil level of the compressor, further includes: if it is determined that the current oil level of the oil storage device is less than a preset lower limit of the oil level of the oil storage device, then determining whether the current oil level of the compressor is less than the preset lower limit of the oil level of the compressor; if it is determined that the current oil level of the compressor is less than the preset lower limit of the oil level of the compressor, then controlling the opening and closing of the first switch to allow the oil storage device to fill the compressor with oil.

[0015] In some embodiments, the control unit controls the opening and closing of the first switch to allow the oil storage device to fill the compressor with oil, including: controlling the first switch to open so that the oil storage device fills the compressor with oil for a third preset time; determining whether the current oil level of the compressor is greater than a preset upper limit of the compressor oil level; the preset upper limit of the compressor oil level is greater than a preset lower limit of the compressor oil level; if it is determined that the current oil level of the compressor is not greater than the preset upper limit of the compressor oil level, then returning to control the first switch to open so that the oil storage device fills the compressor with oil for a third preset time; if it is determined that the current oil level of the compressor is greater than the preset upper limit of the compressor oil level, then controlling the compressor to continue operating normally, returning after a fourth preset time, to continue determining whether the current oil level of the oil storage device is less than the preset lower limit of the oil storage device oil level.

[0016] In some embodiments, the control unit, in conjunction with the current oil level of the compressor and the current oil level of the oil storage device, controls the frequency of the compressor and / or the opening and closing of the first switch to achieve first control of the oil level of the compressor. This further includes: if it is determined that the current oil level of the oil storage device is greater than a preset median oil level of the oil storage device, or if it is determined that the current oil level of the compressor is less than a preset lower oil level limit of the compressor, then determining whether the current oil level of the oil storage device is greater than a preset upper oil level limit of the oil storage device; the preset upper oil level limit of the oil storage device is greater than the preset median oil level of the oil storage device; if it is determined that the current oil level of the oil storage device is greater than the preset upper oil level limit of the oil storage device, then controlling the opening and closing of the first switch to allow the oil storage device to fill the compressor with oil; if it is determined that the current oil level of the oil storage device is not greater than the preset upper oil level limit of the oil storage device, then controlling the compressor to continue normal operation, returning after a fourth preset time, to continue determining whether the current oil level of the oil storage device is less than the preset lower oil level limit of the oil storage device.

[0017] In some embodiments, the control unit controls the opening and closing of the second switch and the gas replenishment switch based on the current gas pressure of the oil storage device to achieve a second control of the oil level of the compressor, including: determining whether the current gas pressure of the oil storage device is greater than a preset pressure limit of the oil storage device; if the current gas pressure of the oil storage device is determined to be greater than the preset pressure limit of the oil storage device, then controlling the second switch to open and controlling the gas replenishment switch to close, for a fifth preset time; determining whether the current gas pressure of the oil storage device is less than a preset pressure limit of the oil storage device. The pressure of the oil storage device is preset to be less than the pressure limit of the oil storage device. If it is determined that the current gas pressure of the oil storage device is less than the preset pressure of the oil storage device, the second switch is controlled to close, and the gas replenishment switch is kept closed. Then, the process returns to continue determining that the current gas pressure of the oil storage device is greater than the preset pressure limit of the oil storage device. If it is determined that the current gas pressure of the oil storage device is not less than the preset pressure of the oil storage device, the process returns to continue controlling the second switch to open and controlling the gas replenishment switch to close, for a fifth preset time.

[0018] In some embodiments, the control unit controls the opening and closing of the second switch and the gas replenishment switch based on the current gas pressure of the oil storage device to achieve a second control of the oil level of the compressor. The control unit further includes: if it is determined that the current gas pressure of the oil storage device is not greater than a preset upper pressure limit of the oil storage device, then it determines whether the current gas pressure of the oil storage device is greater than a preset lower pressure limit of the oil storage device; the preset median pressure of the oil storage device is greater than the preset lower pressure limit of the oil storage device; if it is determined that the current gas pressure of the oil storage device is greater than the preset lower pressure limit of the oil storage device, then it controls the second switch to close and controls the gas replenishment switch to open, continuing for a fifth time. A set time is set; it is determined whether the current gas pressure of the oil storage device is less than the preset median pressure of the oil storage device; the preset median pressure of the oil storage device is less than the preset upper limit pressure of the oil storage device; if it is determined that the current gas pressure of the oil storage device is less than the preset median pressure of the oil storage device, the second switch is controlled to close, and the gas replenishment switch is kept closed, then the process is repeated to continue determining whether the current gas pressure of the oil storage device is greater than the preset upper limit pressure of the oil storage device; if it is determined that the current gas pressure of the oil storage device is not less than the preset median pressure of the oil storage device, the process is repeated to continue controlling the second switch to close, and controlling the gas replenishment switch to open, for a fifth set time.

[0019] In conjunction with the above-described device, the present invention further provides a heat pump unit, comprising: a control device for the heat pump unit described above.

[0020] In conjunction with the above method, the present invention further provides a storage medium comprising a stored program, wherein, when the program is executed, the device containing the storage medium is controlled to perform the control method of the heat pump unit described above.

[0021] Therefore, the solution of the present invention, for a heat pump unit consisting of a compressor, condenser, evaporator, oil-gas separator, and oil storage device (such as an oil storage tank), includes a first switch (such as a first solenoid valve) installed on the pipeline between the oil return port of the oil storage tank and the air intake port of the compressor; a second switch (such as a second solenoid valve) installed on the pipeline between the air return port of the oil storage tank and the outlet of the evaporator; and a gas supply switch (such as a one-way solenoid valve) installed on a bypass branch leading from the pipeline between the outlet of the oil-gas separator and the inlet of the condenser to the gas supply port of the oil storage tank. When the heat pump unit is running stably after startup, the time for the compressor to operate at the oil return frequency is controlled according to the oil level in the oil storage tank and the oil level in the compressor. The system controls the timing of oil replenishment from the oil tank to the compressor. When the compressor's oil level is normal, monitoring the oil level in the oil tank allows the compressor to replenish the oil tank at appropriate high frequencies. Based on the gas pressure in the oil tank, the system controls the opening and closing of the first solenoid valve, the second solenoid valve, and the one-way solenoid valve to ensure that the oil level, gas pressure, and compressor oil level are all within a reasonable range. Therefore, by jointly controlling the oil level, gas pressure, and compressor oil level, the system precisely controls the compressor's oil level, preventing the compressor from operating at insufficient oil levels and ensuring stable and safe operation, thus improving user comfort.

[0022] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention.

[0023] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0024] Figure 1 This is a schematic flowchart of an embodiment of the control method for the heat pump unit of the present invention;

[0025] Figure 2 This is a schematic flowchart of an embodiment of the first process of performing first control on the oil level of the compressor in the method of the present invention;

[0026] Figure 3This is a schematic flowchart of an embodiment of the second process of first controlling the oil level of the compressor in the method of the present invention;

[0027] Figure 4 This is a schematic flowchart of an embodiment of the method of the present invention for controlling the opening and closing of the first switch to inject oil into the compressor;

[0028] Figure 5 This is a schematic flowchart of an embodiment of the third process of first controlling the oil level of the compressor in the method of the present invention;

[0029] Figure 6 This is a schematic flowchart of an embodiment of the first process of performing a second control on the oil level of the compressor in the method of the present invention;

[0030] Figure 7 This is a schematic flowchart of an embodiment of the second process of performing a second control on the oil level of the compressor in the method of the present invention;

[0031] Figure 8 This is a schematic diagram of the structure of an embodiment of the control device for the heat pump unit of the present invention;

[0032] Figure 9 A schematic diagram of a structural embodiment of the compressor oil return system of a heat pump unit;

[0033] Figure 10 A table for monitoring the operating status of the heat pump unit under various operating conditions;

[0034] Figure 11 A flowchart illustrating an embodiment of the joint control logic for a compressor and an oil storage tank;

[0035] Figure 12 This is a flowchart illustrating an embodiment of the pressure control logic for an oil storage tank.

[0036] Referring to the accompanying drawings, the reference numerals in the embodiments of the present invention are as follows:

[0037] 1-First solenoid valve; 2-Second solenoid valve; 3-One-way solenoid valve; 4-Oil-gas separator; 5-Oil storage tank; 6-Compressor; 7-First oil level monitor; 8-Electronic pressure gauge; 9-Second oil level monitor; 102-Acquisition unit; 104-Control unit. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0039] In some solutions, most compressor oil return control systems detect insufficient oil level in compressor 6 and directly increase the compressor frequency to a higher oil return frequency. At this time, the oil level in compressor 6 is low, and high-frequency operation is more likely to cause wear or even damage to the compressor.

[0040] In other solutions, an oil storage device (such as oil tank 5) is used to inject oil into the compressor inlet to ensure the oil level of compressor 6. When using an oil storage device (such as oil tank 5) to inject oil into the compressor inlet to ensure the oil level of compressor 6, there are two scenarios: First, a power unit (such as a pump) is needed to ensure the oil level of compressor 6, but adding a pump or other power unit increases costs. Second, the gas pressure of the oil storage device (such as oil tank 5) is used to inject oil into compressor 6, but insufficient gas volume or low pressure will lead to difficulties in oil injection, while excessive gas volume or high pressure will make it difficult to control the oil level, resulting in an excessively high oil level, which will also damage the compressor. It is evident that when the compressor is injected with oil without a power unit, the pressure control of the oil storage device (such as oil tank 5) is unreasonable, leading to an inability to properly control the oil level of compressor 6. Therefore, a suitable compressor oil return system and control strategy for the heat pump unit are needed to ensure the normal oil level of compressor 6 without affecting the user experience.

[0041] Therefore, the present invention proposes a control method for a heat pump unit, specifically a control method for the compressor oil return system of a heat pump unit. This method involves setting an oil storage tank 5 as a buffer after the oil-gas separator 4, installing a one-way solenoid valve (e.g., one-way solenoid valve 3) between the condenser and the oil storage device (e.g., oil storage tank 5), and installing solenoid valves (e.g., first solenoid valve 1 and second solenoid valve 2) between the oil storage device (e.g., oil storage tank 5) and the compressor 6. Through a combined control strategy of monitoring the oil level of the compressor 6 and the oil level of the oil storage tank 5, the compressor 6 is prevented from operating at the oil return frequency when the oil level is insufficient. Through a reasonable system configuration and control strategy, the oil level and pressure of the oil storage device (e.g., oil storage tank 5) and the compressor 6 are reasonably controlled, ensuring that the oil level, gas pressure, and oil level of the oil storage device (e.g., oil storage tank 5) and the compressor 6 are within reasonable ranges. When the oil level of the compressor 6 is normal, monitoring the oil level of the oil storage tank 5 allows for timely high-frequency operation to replenish the oil in the oil storage tank 5, preventing damage to the compressor 6 caused by high-frequency operation when the oil level is insufficient.

[0042] According to embodiments of the present invention, a control method for a heat pump unit is provided, such as... Figure 1 The diagram shows a flow chart of an embodiment of the method of the present invention. The heat pump unit includes: a compressor 6, a condenser, an evaporator, an oil storage device, and an oil-gas separator 4. The oil storage device is, for example, an oil tank 5. The exhaust port of the compressor 6, after passing through the oil-gas separator 4, is connected to the inlet of the condenser. The outlet of the evaporator is connected to the suction port of the compressor 6. The bottom of the oil-gas separator 4 is connected to the top of the oil storage device via a return oil pipeline. A first bypass pipeline extends from the return oil port of the oil storage device, connecting to the pipeline where the suction port of the compressor 6 is located, i.e., connecting to the pipeline between the outlet of the evaporator and the suction port of the compressor 6, and close to the suction port of the compressor 6. A second bypass pipeline extends from the return oil port of the oil storage device. A pipeline connecting to the outlet of the evaporator, i.e., the pipeline connecting the outlet of the evaporator and the suction port of the compressor 6, and close to the outlet of the evaporator; a third bypass pipeline leading out from the pipeline between the outlet of the oil-gas separator 4 and the inlet of the condenser, connecting to the gas supply port of the oil storage device; a first switch, such as a first solenoid valve 1, is provided on the first bypass pipeline; a second switch, such as a second solenoid valve 2, is provided on the second bypass pipeline; a gas supply switch, such as a one-way solenoid valve 3, is provided on the third bypass pipeline, and the gas supply direction of the gas supply switch is from the pipeline between the outlet of the oil-gas separator 4 and the inlet of the condenser to the gas supply port of the oil storage device.

[0043] Specifically, Figure 9 This is a schematic diagram of an embodiment of the compressor oil return system of a heat pump unit. Figure 9The compressor oil return system of the heat pump unit shown includes: a first solenoid valve 1, a second solenoid valve 2, a one-way solenoid valve 3, an oil-gas separator 4, an oil tank 5, a compressor 6, an evaporator, a condenser, a first oil level monitor 7, an electronic pressure gauge 8, and a second oil level monitor 9. The exhaust port of the compressor 6, after passing through the oil-gas separator 4, is connected to the inlet of the condenser. The outlet of the evaporator is connected to the suction port of the compressor 6. A first pipeline is installed between the oil return port of the oil tank 5 and the suction port of the compressor 6. A second pipeline is installed between the gas return port of the oil tank 5 and the outlet of the evaporator. A third pipeline extends from the pipeline between the outlet of the oil-gas separator 4 and the inlet of the condenser to the gas replenishment port of the oil tank 5. The first solenoid valve 1 is installed on the first pipeline between the oil return port of the oil storage tank 5 and the air intake port of the compressor 6. The second solenoid valve 2 is installed on the second pipeline between the air return port of the oil storage tank 5 and the air intake port of the compressor 6. The one-way solenoid valve 3 is installed on the bypass branch (i.e., the third pipeline) leading from the pipeline between the outlet of the oil-gas separator 4 and the inlet of the condenser to the air replenishment port of the oil storage tank 5. An oil return pipe (e.g., a gravity-driven oil return pipe) is installed between the bottom of the oil-gas separator 4 and the top of the oil storage tank 5. Figure 9 The pipeline represented by the dashed line between the oil-gas separator 4 and the oil storage tank 5.

[0044] In the solution of the present invention, such as Figure 1 As shown, the control method of the heat pump unit includes steps S110 to S120.

[0045] In step S110, after the heat pump unit has been running for a first set time, the oil level monitoring data of the compressor 6 is acquired and recorded as the current oil level of the compressor 6, such as the oil level C of the compressor 6 monitored by the second oil level monitor 9 installed on the compressor; the oil level monitoring data of the oil storage device is acquired and recorded as the current oil level of the oil storage device, such as the oil level S of the oil storage tank 5 monitored by the first oil level monitor 7 installed on the oil storage tank 5; and the gas pressure monitoring data of the oil storage device is acquired and recorded as the current gas pressure of the oil storage device, such as the gas pressure P of the oil storage tank 5 measured by the electronic pressure gauge 8 installed on the oil storage tank 5. The first set time is, for example, time t.

[0046] In step S120, the frequency of the compressor 6 and / or the opening and closing of the first switch are controlled in combination with the current oil level of the compressor 6 and the current oil level of the oil storage device to achieve the first control of the oil level of the compressor 6; and / or, the opening and closing of the second switch and the opening and closing of the gas replenishment switch are controlled according to the current gas pressure of the oil storage device to achieve the second control of the oil level of the compressor 6.

[0047] The present invention addresses the problem that compressor 6 is more prone to wear, malfunction, or damage due to high-frequency oil return when the oil level in the compressor body is insufficient. An oil storage tank 5 is installed after the oil-gas separator 4 as a buffer. A one-way solenoid valve (e.g., one-way solenoid valve 3) is installed between the condenser and the oil storage device (e.g., oil storage tank 5), and solenoid valves (e.g., first solenoid valve 1 and second solenoid valve 2) are installed between the oil storage device (e.g., oil storage tank 5) and the compressor 6. Through a combined control strategy of monitoring the oil level of compressor 6 and oil level of oil storage tank 5, the compressor 6 is prevented from operating at a high oil return frequency when the oil level in the compressor body is insufficient. Through a reasonable system configuration and control strategy, the oil level and pressure of the oil storage device (e.g., oil storage tank 5) and compressor 6 are reasonably controlled, ensuring that the oil level, gas pressure, and oil level of the oil storage device (e.g., oil storage tank 5) and compressor 6 are within reasonable ranges. When the oil level of compressor 6 is normal, high-frequency operation is used to replenish oil in oil storage tank 5 as needed, preventing damage to compressor 6 caused by high-frequency operation when the oil level is insufficient.

[0048] In the solution of this invention, see Figure 9 In the example shown, the first oil level monitor 7 monitors the oil level S in the oil storage tank 5, and the oil level monitor 9 monitors the oil level C in the compressor 6. The output electrical signals of the first oil level monitor 7 and the second oil level monitor 9 are input into the control system. The control system controls the frequency of the compressor 6 and the on / off state (i.e., opening and closing) of the first solenoid valve 1. The electronic pressure gauge 8 monitors the gas pressure P in the oil storage tank 5, and the output electrical signal of the electronic pressure gauge 8 is input into the control system. The control system controls the on / off state (i.e., opening and closing) of the second solenoid valve 2 and the one-way solenoid valve 3. The first solenoid valve 1, the second solenoid valve 2, and the one-way solenoid valve 3 are all normally closed. The first solenoid valve 1 is used to control whether the oil tank 5 injects oil into the compressor 6. The second solenoid valve 2 controls the opening and closing of the hot gas bypass branch to ensure that the refrigerant gas can return to the inlet of the compressor 6 and prevent the pressure of the oil tank 5 from being too high. The one-way solenoid valve 3 is located at the outlet of the oil-gas separator 4 and the inlet of the condenser to ensure that high-pressure gas enters the oil tank 5 and prevents the pressure of the oil tank 5 from being too low, which would result in insufficient power for the oil tank 5 to inject oil into the compressor 6. It can also prevent the oil and gas in the oil tank 5 from flowing back into the condenser and thus into the system circulation, reducing the difficulty of oil return to the compressor 6.

[0049] The present invention comprises two control modules: a first control module and a second control module. The first control module executes a first control strategy, and the second control module executes a second control strategy. The first control module monitors the oil level in the oil storage tank 5 and the compressor 6 using a first oil level monitor 7 and a second oil level monitor 9, respectively. Based on the monitoring signals from the first and second oil level monitors 7 and 9, it controls the on / off (open / close) of the first solenoid valve 1 and whether the compressor 6 operates at the return oil frequency. The second control module monitors the gas pressure in the oil storage tank 5 using an electronic pressure gauge 8. Based on the monitoring signal from the electronic pressure gauge 8, it controls the on / off (open / close) of the second solenoid valve 2 and the one-way solenoid valve 3 to control the gas pressure in the oil storage tank 5. While the two control strategies influence each other, for ease of control, the present invention does not combine the two control strategies but instead separates them into two distinct control strategies.

[0050] Figure 11 This is a flowchart illustrating an embodiment of the joint control logic for compressor 6 and oil tank 5. Figure 12 This is a flowchart illustrating an embodiment of the pressure control logic for oil storage tank 5. See also... Figure 11 In the example shown, for the first control module, the oil level control range of compressor 6 is divided into 3 intervals, with the upper limit C of the oil level of compressor 6 as the starting point. u The lower limit of the oil level C of compressor 6 d The dividing point is defined as follows: the oil level C of compressor 6 is less than the lower limit C of the oil level of compressor 6. d The lower limit of the oil level C of compressor 6 d ≤ Oil level C of compressor 6 < Upper limit C of oil level of compressor 6 u The oil level C of compressor 6 is greater than or equal to the upper limit C of the oil level of compressor 6. u These are respectively named the oil level control range a, b, and c of compressor 6; the oil level control range of oil tank 5 is divided into 4 ranges, with the upper limit S of the oil level in oil tank 5 as the dividing line. u The median oil level S in oil storage tank 5 m The lower limit of the oil level S in oil storage tank 5 d The dividing point is when the oil level S in oil storage tank 5 is less than the lower limit S of the oil level in oil storage tank 5. d The lower limit of the oil level S in oil storage tank 5 d ≤ Oil level S in oil storage tank 5 < Oil level median S in oil storage tank 5 m The median oil level S in oil storage tank 5 m ≤ Oil level S in oil storage tank 5 < Upper limit S of oil level in oil storage tank 5 u The oil level S in oil storage tank 5 is greater than or equal to the upper limit S of the oil level in oil storage tank 5. uThese are respectively named as oil level control range 1, oil level control range 2, oil level control range 3, and oil level control range 4 for oil storage tank 5. Each operating condition range corresponds to the unit's operating strategy, such as... Figure 10 The table shows the operating status of various working conditions.

[0051] Figure 10 This is a table for monitoring the operating status of the heat pump unit under various operating conditions. Figure 10 In the diagram, the oil level control range 1, oil level control range 2, oil level control range 3, oil level control range 4 of oil storage tank 5, and the oil level control range a, oil level control range b, and oil level control range c of compressor 6 represent the oil level height monitoring range of oil storage tank 5 and the oil level monitoring range of compressor 6, respectively.

[0052] See Figure 12 In the example shown, for the second control module, the pressure control range of the oil storage tank 5 is divided into three intervals, with the upper pressure limit P of the oil storage tank 5 as the starting point. u The median pressure P of oil storage tank 5 m The lower pressure limit P of oil storage tank 5 d The dividing points are: the gas pressure P of oil storage tank 5 is less than the lower pressure limit P of oil storage tank 5. d The lower pressure limit P of oil storage tank 5 d ≤Gas pressure P of oil storage tank 5 <Median pressure P of oil storage tank 5 m The median pressure P of oil storage tank 5 m The gas pressure P of oil storage tank 5 is less than the upper pressure limit P of oil storage tank 5. u The gas pressure P of oil storage tank 5 is greater than or equal to the upper pressure limit P of oil storage tank 5. u .

[0053] In the solution of this invention, the control logic is as follows: Figure 11 , Figure 12 As shown. See also Figure 11 and Figure 12 In the example shown, compressor 6 starts, and the heat pump unit begins to operate according to the load power until it stabilizes after a period of time t. Here, time t is an empirical value, mainly related to the type of heat pump unit, and is approximately 60 seconds. The first oil level monitor 7 and the second oil level monitor 9 output electrical signals, and the first control module starts operating; the second control module outputs electrical signals from the first oil level monitor 7 and the second oil level monitor 9, and the second control module starts operating.

[0054] In some embodiments, step S120 combines the current oil level of the compressor 6 and the current oil level of the oil storage device to control the frequency of the compressor 6 and / or the opening and closing of the first switch to achieve the first control of the oil level of the compressor 6, including: a first process of performing the first control of the oil level of the compressor 6.

[0055] The following is combined with Figure 2 The flowchart shown is a schematic diagram of an embodiment of the first process of first controlling the oil level of the compressor 6 in the method of the present invention. The specific process of the first process of first controlling the oil level of the compressor 6 in step S120 is further explained, including steps S210 to S240.

[0056] Step S210: Under normal operation of the compressor 6, determine whether the current oil level of the oil storage device is lower than the preset lower limit of the oil level of the oil storage device.

[0057] Step S220: If, under normal operation of the compressor 6, the current oil level of the oil storage device is determined to be lower than a preset lower limit for the oil level of the oil storage device, then the compressor 6 is controlled to operate at a preset oil return frequency for a second preset time. The preset oil return frequency is, for example, oil return frequency f, and the second preset time is, for example, t. c time.

[0058] Step S230: When the compressor 6 is running normally and the current oil level of the oil storage device is less than the preset lower limit of the oil level of the oil storage device, after controlling the compressor 6 to run at the preset oil return frequency of the compressor 6 for a second preset time, determine whether the current oil level of the oil storage device is greater than the preset median oil level of the oil storage device; the preset median oil level of the oil storage device is greater than the preset lower limit of the oil level of the oil storage device.

[0059] Step S240: When the compressor 6 is running normally and the current oil level of the oil storage device is less than the preset lower limit of the oil level of the oil storage device, after controlling the compressor 6 to run at the preset oil return frequency of the compressor 6 for a second preset time, if it is determined that the current oil level of the oil storage device is not greater than the preset median oil level of the oil storage device, then return to the previous step to continue controlling the compressor 6 to run at the preset oil return frequency of the compressor 6 for a second preset time.

[0060] Specifically, see Figure 11In the example shown, after receiving the electrical signals output by the first oil level monitor 7 and the second oil level monitor 9, the first control module needs time t1 after completing each control process before it can process the electrical signals output by the first oil level monitor 7 and the second oil level monitor 9 again. This prevents frequent system control from causing frequent high-low frequency switching of the compressor 6. Here, time t1 is an empirical value. Figure 11 As shown, the control flow of the first control module, namely the joint control logic of compressor 6 and oil tank 5, includes:

[0061] Step 11: After the heat pump unit has been running for time t, input the electrical signals detected by the first oil level monitor 7 and the second oil level monitor 9. Then, execute step 12 to first determine whether the oil level S in the oil storage tank 5 is lower than the lower limit S of the oil level in the oil storage tank 5. d .

[0062] Step 12: First, determine whether the oil level S in oil storage tank 5 is lower than the lower limit S of the oil level in oil storage tank 5. d If the oil level S in oil storage tank 5 is less than the lower limit S of the oil level in oil storage tank 5. d If the oil level S in storage tank 5 is less than the lower limit S of the oil level in storage tank 5, then proceed to step 13; d Then proceed to step 15.

[0063] Step 13: If the oil level S in oil storage tank 5 is less than the lower limit S of the oil level in oil storage tank 5... d Then control compressor 6 to run at the oil return frequency f. c Time, then proceed to step 14.

[0064] Step 14: Determine whether the oil level S in oil storage tank 5 is greater than the median oil level S in oil storage tank 5. m If the oil level S in oil storage tank 5 is less than or equal to the median oil level S in oil storage tank 5 m Then compressor 6 operates at the oil return frequency f. c After a certain period of time, a second assessment will be conducted to determine whether the oil level S in storage tank 5 is greater than the median oil level S in storage tank 5. m If the oil level S in oil storage tank 5 is greater than the median oil level S in oil storage tank 5... m Then, it is further determined whether the oil level S in oil storage tank 5 is greater than the upper limit S of the oil level in oil storage tank 5. u That is, proceed to step 18.

[0065] In some embodiments, step S120 combines the current oil level of the compressor 6 and the current oil level of the oil storage device to control the frequency of the compressor 6 and / or the opening and closing of the first switch to achieve the first control of the oil level of the compressor 6, and further includes a second process of performing the first control of the oil level of the compressor 6.

[0066] The following is combined with Figure 3 The schematic diagram shows an embodiment of the second process of first controlling the oil level of the compressor 6 in the method of the present invention. It further illustrates the specific process of the second process of first controlling the oil level of the compressor 6 in step S120, including steps S310 to S320.

[0067] Step S310: If, under normal operation of the compressor 6, it is determined that the current oil level of the oil storage device is less than the preset lower limit of the oil level of the oil storage device, then it is determined whether the current oil level of the compressor 6 is less than the preset lower limit of the oil level of the compressor 6.

[0068] Step S320: When the compressor 6 is operating normally and the current oil level of the oil storage device is lower than the preset lower limit of the oil level of the oil storage device, if it is determined that the current oil level of the compressor 6 is lower than the preset lower limit of the oil level of the compressor 6, then the opening and closing of the first switch is controlled so that the oil storage device fills the compressor 6 with oil.

[0069] Specifically, such as Figure 11 As shown, the control flow of the first control module, namely the joint control logic of compressor 6 and oil tank 5, includes the following after step 11:

[0070] Step 15: Determine whether the oil level S in oil storage tank 5 is lower than the lower limit S of the oil level in oil storage tank 5. d At that time, the oil level S in oil storage tank 5 shall not be less than the lower limit S of the oil level in oil storage tank 5. d Then continue to determine whether the oil level C of compressor 6 is lower than the lower limit C of the oil level of compressor 6. d If the oil level C of compressor 6 is less than the lower limit C of the oil level of compressor 6. d If the oil level C of compressor 6 is not lower than the lower limit C of oil level C of compressor 6, then proceed to step 16; d Then, it is further determined whether the oil level S in oil storage tank 5 is greater than the upper limit S of the oil level in oil storage tank 5. u That is, proceed to step 18.

[0071] Step 16: If the oil level C of compressor 6 is less than the lower limit C of the oil level of compressor 6... d Then, control the oil storage tank 5 to inject oil into the compressor 6.

[0072] In some embodiments, the specific process of controlling the opening and closing of the first switch in step S320 to allow the oil storage device to inject oil into the compressor 6 is described in the following exemplary description.

[0073] The following is combined with Figure 4The diagram shows a flowchart of an embodiment of the method of the present invention, which controls the opening and closing of the first switch to inject oil into the compressor 6. The specific process of controlling the opening and closing of the first switch to inject oil into the compressor 6 in step S320 is further explained, including steps S410 to S440.

[0074] Step S410: Control the first switch to open, so that the oil storage device can inject oil into the compressor 6 for a third set time. The third set time is as follows: t s time.

[0075] Step S420: After controlling the first switch to open so that the oil storage device can inject oil into the compressor 6 for a third set time, determine whether the current oil level of the compressor 6 is greater than the preset upper limit of the oil level of the compressor 6; the preset upper limit of the oil level of the compressor 6 is greater than the preset lower limit of the oil level of the compressor 6.

[0076] Step S430: After controlling the first switch to open so that the oil storage device can fill the compressor 6 with oil for a third set time, if it is determined that the current oil level of the compressor 6 is not greater than the preset upper limit of the oil level of the compressor 6, then return to the previous step to continue controlling the first switch to open so that the oil storage device can fill the compressor 6 with oil for a third set time.

[0077] Step S440: After controlling the first switch to open so that the oil storage device can inject oil into the compressor 6 for a third set time, if it is determined that the current oil level of the compressor 6 is greater than the preset upper limit of the oil level of the compressor 6, the compressor is controlled to continue to operate normally. After a fourth set time, the process returns to determine whether the current oil level of the oil storage device is less than the preset lower limit of the oil level of the oil storage device while the compressor 6 is operating normally.

[0078] Specifically, such as Figure 11 As shown, the control flow of the first control module, namely the joint control logic of compressor 6 and oil tank 5, includes the following after step 16:

[0079] In step 16, controlling the oil tank 5 to inject oil into the compressor 6 specifically includes: controlling the first solenoid valve 1 to open (i.e., controlling the first solenoid valve 1 to be connected), so that the oil tank 5 injects oil into the compressor 6. s Time, then proceed to step 17.

[0080] Step 17: Determine whether the oil level C of compressor 6 is greater than the upper limit C of the oil level of compressor 6. u If the oil level C of compressor 6 is less than or equal to the upper limit Cu of oil level in compressor 6, then continue adding oil. sTime; if the oil level C of compressor 6 is greater than the upper limit Cu of oil level of compressor 6, then control compressor 6 to operate under normal load.

[0081] In some embodiments, step S120 combines the current oil level of the compressor 6 and the current oil level of the oil storage device to control the frequency of the compressor 6 and / or the opening and closing of the first switch to achieve the first control of the oil level of the compressor 6, and also includes a third process of performing the first control of the oil level of the compressor 6.

[0082] The following is combined with Figure 5 The schematic diagram shows an embodiment of the third process of first controlling the oil level of the compressor 6 in the method of the present invention. It further illustrates the specific process of the third process of first controlling the oil level of the compressor 6 in step S120, including steps S510 to S530.

[0083] Step S510: When the compressor 6 is operating normally and the current oil level of the oil storage device is less than the preset lower limit of the oil level of the oil storage device, after controlling the compressor 6 to run at the preset oil return frequency of the compressor 6 for a second preset time, if it is determined that the current oil level of the oil storage device is greater than the preset middle level of the oil storage device, or, when the compressor 6 is operating normally and the current oil level of the oil storage device is less than the preset lower limit of the oil level of the oil storage device, if it is determined that the current oil level of the compressor 6 is less than the preset lower limit of the oil level of the compressor 6, then it is determined whether the current oil level of the oil storage device is greater than the preset upper limit of the oil level of the oil storage device; the preset upper limit of the oil level of the oil storage device is greater than the preset middle level of the oil level of the oil storage device.

[0084] Step S520: When the compressor 6 is operating normally and the current oil level of the oil storage device is less than the preset lower limit of the oil level of the oil storage device, after controlling the compressor 6 to run at the preset oil return frequency for a second preset time, if the current oil level of the oil storage device is greater than the preset median oil level of the oil storage device; or, when the compressor 6 is operating normally and the current oil level of the oil storage device is less than the preset lower limit of the oil level of the oil storage device, if it is determined that the current oil level of the compressor 6 is less than the preset lower limit of the oil level of the compressor 6, and if it is determined that the current oil level of the oil storage device is greater than the preset upper limit of the oil level of the oil storage device, then the opening and closing of the first switch is controlled so that the oil storage device fills the compressor 6 with oil. The process of controlling the opening and closing of the first switch in step S520 to fill the compressor 6 with oil can be found in the description of step S320, specifically: controlling the first switch to open so that the oil storage device fills the compressor 6 with oil for a third preset time, such as t. s Time. After controlling the first switch to open so that the oil storage device can fill the compressor 6 with oil for a third set time, it is determined whether the current oil level of the compressor 6 is greater than the preset upper limit of the oil level of the compressor 6; the preset upper limit of the oil level of the compressor 6 is greater than the preset lower limit of the oil level of the compressor 6. After controlling the first switch to open so that the oil storage device can fill the compressor 6 with oil for a third set time, if it is determined that the current oil level of the compressor 6 is not greater than the preset upper limit of the oil level of the compressor 6, the process returns to the previous state to continue controlling the first switch to open so that the oil storage device can fill the compressor 6 with oil for a third set time. After controlling the first switch to open so that the oil storage device can fill the compressor 6 with oil for a third set time, if it is determined that the current oil level of the compressor 6 is greater than the preset upper limit of the oil level of the compressor 6, the compressor continues to operate normally, and after a fourth set time, the process returns to the previous state to continue determining whether the current oil level of the oil storage device is less than the preset lower limit of the oil level of the oil storage device while the compressor 6 is operating normally.

[0085] Step S530: When the compressor 6 is operating normally and the current oil level of the oil storage device is less than the preset lower limit of the oil level of the oil storage device, after controlling the compressor 6 to run at the preset oil return frequency for a second preset time, if the current oil level of the oil storage device is greater than the preset median oil level of the oil storage device; or, when the compressor 6 is operating normally and the current oil level of the oil storage device is less than the preset lower limit of the oil level of the oil storage device, if it is determined that the current oil level of the compressor 6 is less than the preset lower limit of the oil level of the compressor 6, and if it is determined that the current oil level of the oil storage device is not greater than the preset upper limit of the oil level of the oil storage device, then the compressor is controlled to continue operating normally, and returns after a fourth preset time, so as to continue to determine whether the current oil level of the oil storage device is less than the preset lower limit of the oil level of the oil storage device while the compressor 6 is operating normally.

[0086] Specifically, such as Figure 11 As shown, the control flow of the first control module, namely the joint control logic of compressor 6 and oil tank 5, further includes the following after step 14 or step 15:

[0087] Step 18: Determine whether the oil level S in oil storage tank 5 is greater than the upper limit S of the oil level in oil storage tank 5. u If this condition is met, then oil tank 5 will inject oil t into compressor 6. s If the time condition is not met, then proceed to step 17; if the condition is not met, then control compressor 6 to operate under normal load, and then proceed to step 19.

[0088] Step 19: After the compressor 6 is running under normal load, after time t1, the control loop is entered, and the control strategy is run again to process the electrical signals output by the first oil level monitor 7 and the second oil level monitor 9. This completes the control flow of the first control module.

[0089] The present invention addresses the problem that if the oil return process cannot be accurately controlled, resulting in excessively frequent oil return, high-frequency operation of the heat pump unit will affect user comfort, cause additional power consumption, and affect the compressor's lifespan. This is achieved by setting an oil storage tank 5 after the oil-gas separator 4 as a buffer, reducing the number of times the compressor 6 operates at the oil return frequency. Furthermore, through oil level monitoring and related control strategies in the oil storage tank 5, the oil level in the tank is rationally controlled to ensure sufficient oil level when the tank 5 injects oil into the compressor 6.

[0090] In some embodiments, step S120 controls the opening and closing of the second switch and the opening and closing of the gas replenishment switch according to the current gas pressure of the oil storage device, so as to realize the second control of the oil level of the compressor 6, including: a first process of performing the second control of the oil level of the compressor 6.

[0091] The following is combined with Figure 6 The schematic diagram shows an embodiment of the first process of performing a second control on the oil level of the compressor 6 in the method of the present invention. It further illustrates the specific process of the first process of performing a second control on the oil level of the compressor 6 in step S120, including steps S610 to S650.

[0092] Step S610: Under normal operation of the compressor 6, determine whether the current gas pressure of the oil storage device is greater than the preset pressure limit of the oil storage device.

[0093] Step S620: If, under normal operation of the compressor 6, it is determined that the current gas pressure of the oil storage device is greater than the preset pressure limit of the oil storage device, then the second switch is opened and the gas replenishment switch is closed, continuing for a fifth preset time. The fifth preset time is t. p time.

[0094] Step S630: When the compressor 6 is operating normally and the current gas pressure of the oil storage device is greater than the preset upper pressure limit of the oil storage device, after controlling the second switch to open and the gas supply switch to close for a fifth preset time, it is determined whether the current gas pressure of the oil storage device is less than the preset median pressure of the oil storage device; the preset median pressure of the oil storage device is less than the preset upper pressure limit of the oil storage device.

[0095] In step S640, when the compressor 6 is operating normally and the current gas pressure of the oil storage device is greater than the preset upper limit of the oil storage device pressure, after controlling the second switch to open and the gas supply switch to close for a fifth preset time, if it is determined that the current gas pressure of the oil storage device is less than the preset median pressure of the oil storage device, then the second switch is controlled to close and the gas supply switch is kept closed, and then the process returns to the previous step to continue determining that the current gas pressure of the oil storage device is greater than the preset upper limit of the oil storage device pressure while the compressor 6 is operating normally.

[0096] In step S650, when the compressor 6 is operating normally and the current gas pressure of the oil storage device is greater than the preset upper limit of the oil storage device pressure, after controlling the second switch to open and the gas supply switch to close for a fifth preset time, if it is determined that the current gas pressure of the oil storage device is not less than the preset median pressure of the oil storage device, then return to the previous step to continue controlling the second switch to open and the gas supply switch to close for a fifth preset time.

[0097] Specifically, such as Figure 12 As shown, the pressure control logic for oil storage tank 5 includes:

[0098] Step 21: The second control module determines whether the pressure P of the oil storage tank 5 is greater than the upper pressure limit P of the oil storage tank 5 based on the electrical signal input from the first oil level monitor 7 and the second oil level monitor 9. u If the pressure P of oil storage tank 5 is greater than the upper pressure limit P of oil storage tank 5. u If the pressure P of oil storage tank 5 is too high, then step 22 is executed; if the pressure P of oil storage tank 5 is not greater than the upper pressure limit P of oil storage tank 5, then... u Then proceed to step 24.

[0099] Step 22: Control the opening of the second solenoid valve 2 and the closing of the one-way solenoid valve 3, for a continuous period of time. p After a period of time, it is then determined whether the pressure P of oil storage tank 5 is less than the median pressure P of oil storage tank 5. m That is, proceed to step 23.

[0100] Step 23: Determine whether the pressure P of oil storage tank 5 is less than the median pressure P of oil storage tank 5. m If the pressure P of oil storage tank 5 is less than the median pressure P of oil storage tank 5... m If the pressure in oil tank 5 is still considered high, return to step 22 to continue the operation of opening the second solenoid valve 2 and closing the one-way solenoid valve 3; if the pressure P in oil tank 5 is less than the median pressure P in oil tank 5... m Then, control the closing of the second solenoid valve 2 and the one-way solenoid valve 3, and then return to step 21.

[0101] In some embodiments, step S120, based on the current gas pressure of the oil storage device, controls the opening and closing of the second switch and the opening and closing of the gas replenishment switch to achieve the second control of the oil level of the compressor 6, and further includes: a second process of performing the second control of the oil level of the compressor 6.

[0102] The following is combined with Figure 7 The schematic diagram shows an embodiment of the second process of performing a second control on the oil level of the compressor 6 in the method of the present invention. It further illustrates the specific process of the second process of performing a second control on the oil level of the compressor 6 in step S120, including steps S710 to S750.

[0103] Step S710: If, under normal operation of the compressor 6, it is determined that the current gas pressure of the oil storage device is not greater than the preset upper pressure limit of the oil storage device, then it is determined whether the current gas pressure of the oil storage device is greater than the preset lower pressure limit of the oil storage device; the preset median pressure of the oil storage device is greater than the preset lower pressure limit of the oil storage device.

[0104] In step S720, if the compressor 6 is operating normally and the current gas pressure of the oil storage device is not greater than the preset upper pressure limit of the oil storage device, and it is determined that the current gas pressure of the oil storage device is greater than the preset lower pressure limit of the oil storage device, then the second switch is controlled to close and the gas replenishment switch is controlled to open, for a fifth preset time.

[0105] Step S730: When the compressor 6 is operating normally and the current gas pressure of the oil storage device is not greater than the preset upper pressure limit of the oil storage device, after controlling the second switch to close and the gas replenishment switch to open for a fifth preset time, it is determined whether the current gas pressure of the oil storage device is less than the preset median pressure of the oil storage device; the preset median pressure of the oil storage device is less than the preset upper pressure limit of the oil storage device.

[0106] In step S740, when the compressor 6 is operating normally and the current gas pressure of the oil storage device is not greater than the preset upper pressure limit of the oil storage device, after controlling the second switch to open and the gas supply switch to close for a fifth preset time, if it is determined that the current gas pressure of the oil storage device is less than the preset median pressure of the oil storage device, then the second switch is controlled to close and the gas supply switch is kept closed. Then the process returns to the previous step, so as to continue to determine that the current gas pressure of the oil storage device is greater than the preset upper pressure limit of the oil storage device while the compressor 6 is operating normally.

[0107] In step S750, when the compressor 6 is operating normally and the current gas pressure of the oil storage device is not greater than the preset upper limit of the oil storage device pressure, after controlling the second switch to open and the gas replenishment switch to close for a fifth preset time, if it is determined that the current gas pressure of the oil storage device is not less than the preset median pressure of the oil storage device, then return to the previous step to continue controlling the second switch to close and the gas replenishment switch to open for a fifth preset time.

[0108] Specifically, such as Figure 12 As shown, the pressure control logic for oil storage tank 5, after step 21, also includes:

[0109] Step 24: If the pressure P of oil storage tank 5 is not greater than the upper pressure limit P of oil storage tank 5 u Then determine whether the pressure P of oil storage tank 5 is less than the lower pressure limit P of oil storage tank 5. d If the pressure P of oil storage tank 5 is less than the lower pressure limit P of oil storage tank 5. d If the pressure P of oil storage tank 5 is less than the lower pressure limit P of oil storage tank 5, then proceed to step 25; d Then close the second solenoid valve 2 and the one-way solenoid valve 3, and then return to step 21.

[0110] Step 25: Close the second solenoid valve 2, open the one-way solenoid valve 3, and continue for t. p After a certain time, continue to determine whether the pressure P of oil storage tank 5 is greater than the median pressure P of oil storage tank 5. m That is, proceed to step 26.

[0111] Step 26: Determine whether the pressure P of oil storage tank 5 is greater than the median pressure P of oil storage tank 5. m If the pressure P of oil storage tank 5 is not greater than the median pressure P of oil storage tank 5... m Then return to step 25 to continue closing the second solenoid valve 2 and opening the one-way solenoid valve 3 for t. p Time; if the pressure P of oil storage tank 5 is greater than the median pressure P of oil storage tank 5. m If the second solenoid valve 2 and the one-way solenoid valve 3 are closed, then return to step 21. The entire control process is completed.

[0112] The present invention addresses the problems of insufficient gas and low pressure in the oil storage tank 5, making it difficult to inject oil into the compressor 6 without a driving device (such as a pump); and excessive gas pressure in the oil storage tank 5, making it difficult to control the oil injection level. By controlling the pressure of the oil storage tank 5 without installing a return oil driving device, stable oil injection into the compressor is achieved. No power device is needed; the oil storage device (such as the oil storage tank 5) is used to inject oil into the compressor. A one-way solenoid valve (such as one-way solenoid valve 3) is installed between the condenser and the oil storage device (such as the oil storage tank 5), and solenoid valves (such as the first solenoid valve 1 and the second solenoid valve 2) are installed between the oil storage device (such as the oil storage tank 5) and the compressor 6. These are used to replenish or return gas to the oil storage device (such as the oil storage tank 5) to maintain its pressure. Through the gas replenishment device, the return gas bypass device, and the pressure monitoring and related control strategies of the oil storage tank 5, the pressure and volume of the oil storage tank 5 are controlled to ensure sufficient power for the oil storage tank 5 to inject oil into the compressor 6.

[0113] After the control process of the second control module is completed, it processes the electrical signal of the electronic pressure gauge 8 in real time without any interval. Among these processes, the upper limit C of the oil level in the compressor 6 is... u The lower limit of the oil level C of compressor 6d The upper limit of the oil level S in oil storage tank 5 u The median oil level S in oil storage tank 5 m The lower limit of the oil level S in oil storage tank 5 d The upper pressure limit P of oil storage tank 5 u The median pressure P of oil storage tank 5 m The lower pressure limit P of oil storage tank 5 d Oil return frequency f, time t, time t1, time t c Time t p Time t s All of these are related to the type of heat pump unit; time t, time t1, and time t2 are set according to actual needs. c Time t p Time t s The recommended values ​​are 60s, 120s, 40s, 30s, and 10s.

[0114] In the present invention, the gas pressure and volume control logic of the oil storage device (such as oil storage tank 5) is as follows: the gas volume and gas pressure are monitored by the oil level monitoring device (such as the first oil level monitor 7) and the pressure monitoring device (such as the electronic pressure gauge 8) of the oil storage tank 5, and a suitable control process is used to ensure that the tank volume and pressure meet the operating requirements. The oil return and oil injection control logic of the compressor 6 is as follows: the oil level monitoring device (such as the second oil level monitor 9) of the compressor 6 and the oil level monitoring device (such as the first oil level monitor 7) of the oil storage tank 5 are used to determine the operating range of the system and perform oil return, oil injection, or normal load operation processing. Oil storage tank gas injection bypass: a bypass pipe is set between the oil-gas separation device (such as the oil-gas separator 4) and the condenser inlet, and connected to the oil storage tank 5 through the gas injection switch (such as the one-way solenoid valve 3) to inject gas, ensuring that the internal pressure of the oil storage tank 5 is not lower than the set lower limit pressure. By monitoring the oil level of oil tank 5 and compressor 6 and implementing related control strategies, the oil level of oil tank 5 can be reasonably controlled to ensure sufficient oil level when oil tank 5 injects oil into compressor 6, thus avoiding oil shortage in the heat pump unit and damage to compressor 6. The effect is obvious.

[0115] The technical solution of this embodiment, for a heat pump unit consisting of a compressor (e.g., compressor 6), a condenser, an evaporator, an oil-gas separator (e.g., oil-gas separator 4), and an oil storage device (e.g., oil storage tank 5), includes a first switch (e.g., a first solenoid valve 1) installed on the pipeline between the oil return port of the oil storage tank 5 and the suction port of the compressor 6; a second switch (e.g., a second solenoid valve 2) installed on the pipeline between the gas return port of the oil storage tank 5 and the outlet of the evaporator; and a gas supply switch (e.g., a one-way solenoid valve 3) installed on a bypass branch leading from the pipeline between the outlet of the oil-gas separator 4 and the inlet of the condenser to the gas supply port of the oil storage tank 5. When the heat pump unit is running stably after startup, the compressor 6 is controlled according to the oil level in the oil storage tank 5 and the oil level in the compressor 6, based on the oil return frequency. The system controls the operating time and the oil tank 5 to replenish the compressor 6 with oil. When the compressor 6 has a normal oil level, the system monitors the oil level in the oil tank 5 and ensures that the compressor 6 operates at a high frequency to replenish the oil tank 5 as needed. Based on the gas pressure in the oil tank 5, the system controls the opening and closing of the first solenoid valve 1, the second solenoid valve 2, and the one-way solenoid valve 3 to ensure that the oil level, gas pressure, and compressor 6 are all within a reasonable range. Therefore, by jointly controlling the oil level and gas pressure in the oil tank 5 and the oil level in the compressor 6, the system precisely controls the oil level of the compressor 6, preventing it from operating at a low oil return frequency when the oil level is insufficient. This ensures stable and safe operation of the compressor and improves user comfort.

[0116] According to an embodiment of the present invention, a control device for a heat pump unit corresponding to a control method for a heat pump unit is also provided. See also Figure 8The diagram shows a structural schematic of an embodiment of the device of the present invention. The heat pump unit includes: a compressor 6, a condenser, an evaporator, an oil storage device, and an oil-gas separator 4. The oil storage device is, for example, an oil tank 5. The exhaust port of the compressor 6, after passing through the oil-gas separator 4, is connected to the inlet of the condenser. The outlet of the evaporator is connected to the suction port of the compressor 6. The bottom of the oil-gas separator 4 is connected to the top of the oil storage device via a return oil pipeline. A first bypass pipeline extends from the return oil port of the oil storage device, connecting to the pipeline where the suction port of the compressor 6 is located, i.e., connecting to the pipeline between the outlet of the evaporator and the suction port of the compressor 6, and close to the suction port of the compressor 6. A second bypass pipeline extends from the return oil port of the oil storage device. A pipeline connecting to the outlet of the evaporator, i.e., the pipeline connecting the outlet of the evaporator and the suction port of the compressor 6, and close to the outlet of the evaporator; a third bypass pipeline leading out from the pipeline between the outlet of the oil-gas separator 4 and the inlet of the condenser, connecting to the gas supply port of the oil storage device; a first switch, such as a first solenoid valve 1, is provided on the first bypass pipeline; a second switch, such as a second solenoid valve 2, is provided on the second bypass pipeline; a gas supply switch, such as a one-way solenoid valve 3, is provided on the third bypass pipeline, and the gas supply direction of the gas supply switch is from the pipeline between the outlet of the oil-gas separator 4 and the inlet of the condenser to the gas supply port of the oil storage device.

[0117] Specifically, Figure 9 This is a schematic diagram of an embodiment of the compressor oil return system of a heat pump unit. Figure 9 The compressor oil return system of the heat pump unit shown includes: a first solenoid valve 1, a second solenoid valve 2, a one-way solenoid valve 3, an oil-gas separator 4, an oil tank 5, a compressor 6, an evaporator, a condenser, a first oil level monitor 7, an electronic pressure gauge 8, and a second oil level monitor 9. The exhaust port of the compressor 6, after passing through the oil-gas separator 4, is connected to the inlet of the condenser. The outlet of the evaporator is connected to the suction port of the compressor 6. A first pipeline is installed between the oil return port of the oil tank 5 and the suction port of the compressor 6. A second pipeline is installed between the gas return port of the oil tank 5 and the outlet of the evaporator. A third pipeline extends from the pipeline between the outlet of the oil-gas separator 4 and the inlet of the condenser to the gas replenishment port of the oil tank 5. The first solenoid valve 1 is installed on the first pipeline between the oil return port of the oil storage tank 5 and the air intake port of the compressor 6. The second solenoid valve 2 is installed on the second pipeline between the air return port of the oil storage tank 5 and the air intake port of the compressor 6. The one-way solenoid valve 3 is installed on the bypass branch (i.e., the third pipeline) leading from the pipeline between the outlet of the oil-gas separator 4 and the inlet of the condenser to the air replenishment port of the oil storage tank 5. An oil return pipe (e.g., a gravity-driven oil return pipe) is installed between the bottom of the oil-gas separator 4 and the top of the oil storage tank 5. Figure 9 The pipeline represented by the dashed line between the oil-gas separator 4 and the oil storage tank 5.

[0118] In the solution of the present invention, such as Figure 8 As shown, the control device of the heat pump unit includes: an acquisition unit 102 and a control unit 104.

[0119] The acquisition unit 102 is configured to acquire, after the heat pump unit has been running for a first set time, the following: acquiring the oil level monitoring data of the compressor 6, recorded as the current oil level of the compressor 6 (e.g., the oil level C monitored by the second oil level monitor 9 on the compressor); acquiring the oil level monitoring data of the oil storage device, recorded as the current oil level of the oil storage device (e.g., the oil level S monitored by the first oil level monitor 7 on the oil storage tank 5); and acquiring the gas pressure monitoring data of the oil storage device, recorded as the current gas pressure of the oil storage device (e.g., the gas pressure P of the oil storage tank 5 as measured by the electronic pressure gauge 8 on the oil storage tank 5). The specific functions and processing of the acquisition unit 102 are described in step S110. The first set time is, for example, time t.

[0120] The control unit 104 is configured to, in conjunction with the current oil level of the compressor 6 and the current oil level of the oil storage device, control the frequency of the compressor 6 and / or the opening and closing of the first switch to achieve first control of the oil level of the compressor 6; and / or, based on the current gas pressure of the oil storage device, control the opening and closing of the second switch and the opening and closing of the gas replenishment switch to achieve second control of the oil level of the compressor 6. The specific functions and processing of this control unit 104 are described in step S120.

[0121] The present invention addresses the problem that compressor 6 is more prone to wear, malfunction, or damage due to high-frequency oil return when the oil level in the compressor body is insufficient. An oil storage tank 5 is installed after the oil-gas separator 4 as a buffer. A one-way solenoid valve (e.g., one-way solenoid valve 3) is installed between the condenser and the oil storage device (e.g., oil storage tank 5), and solenoid valves (e.g., first solenoid valve 1 and second solenoid valve 2) are installed between the oil storage device (e.g., oil storage tank 5) and the compressor 6. Through a combined control strategy of monitoring the oil level of compressor 6 and oil level of oil storage tank 5, the compressor 6 is prevented from operating at a high oil return frequency when the oil level in the compressor body is insufficient. Through a reasonable system configuration and control strategy, the oil level and pressure of the oil storage device (e.g., oil storage tank 5) and compressor 6 are reasonably controlled, ensuring that the oil level, gas pressure, and oil level of the oil storage device (e.g., oil storage tank 5) and compressor 6 are within reasonable ranges. When the oil level of compressor 6 is normal, high-frequency operation is used to replenish oil in oil storage tank 5 as needed, preventing damage to compressor 6 caused by high-frequency operation when the oil level is insufficient.

[0122] In the solution of this invention, see Figure 9 In the example shown, the first oil level monitor 7 monitors the oil level S in the oil storage tank 5, and the oil level monitor 9 monitors the oil level C in the compressor 6. The output electrical signals of the first oil level monitor 7 and the second oil level monitor 9 are input into the control system. The control system controls the frequency of the compressor 6 and the on / off state (i.e., opening and closing) of the first solenoid valve 1. The electronic pressure gauge 8 monitors the gas pressure P in the oil storage tank 5, and the output electrical signal of the electronic pressure gauge 8 is input into the control system. The control system controls the on / off state (i.e., opening and closing) of the second solenoid valve 2 and the one-way solenoid valve 3. The first solenoid valve 1, the second solenoid valve 2, and the one-way solenoid valve 3 are all normally closed. The first solenoid valve 1 is used to control whether the oil tank 5 injects oil into the compressor 6. The second solenoid valve 2 controls the opening and closing of the hot gas bypass branch to ensure that the refrigerant gas can return to the inlet of the compressor 6 and prevent the pressure of the oil tank 5 from being too high. The one-way solenoid valve 3 is located at the outlet of the oil-gas separator 4 and the inlet of the condenser to ensure that high-pressure gas enters the oil tank 5 and prevents the pressure of the oil tank 5 from being too low, which would result in insufficient power for the oil tank 5 to inject oil into the compressor 6. It can also prevent the oil and gas in the oil tank 5 from flowing back into the condenser and thus into the system circulation, reducing the difficulty of oil return to the compressor 6.

[0123] The present invention comprises two control modules: a first control module and a second control module. The first control module executes a first control strategy, and the second control module executes a second control strategy. The first control module monitors the oil level in the oil storage tank 5 and the compressor 6 using a first oil level monitor 7 and a second oil level monitor 9, respectively. Based on the monitoring signals from the first and second oil level monitors 7 and 9, it controls the on / off (open / close) of the first solenoid valve 1 and whether the compressor 6 operates at the return oil frequency. The second control module monitors the gas pressure in the oil storage tank 5 using an electronic pressure gauge 8. Based on the monitoring signal from the electronic pressure gauge 8, it controls the on / off (open / close) of the second solenoid valve 2 and the one-way solenoid valve 3 to control the gas pressure in the oil storage tank 5. While the two control strategies influence each other, for ease of control, the present invention does not combine the two control strategies but instead separates them into two distinct control strategies.

[0124] Figure 11 This is a flowchart illustrating an embodiment of the joint control logic for compressor 6 and oil tank 5. Figure 12 This is a flowchart illustrating an embodiment of the pressure control logic for oil storage tank 5. See also... Figure 11 In the example shown, for the first control module, the oil level control range of compressor 6 is divided into 3 intervals, with the upper limit C of the oil level of compressor 6 as the starting point. u The lower limit of the oil level C of compressor 6 d The dividing point is defined as follows: the oil level C of compressor 6 is less than the lower limit C of the oil level of compressor 6. dThe lower limit of the oil level C of compressor 6 d ≤ Oil level C of compressor 6 < Upper limit C of oil level of compressor 6 u The oil level C of compressor 6 is greater than or equal to the upper limit C of the oil level of compressor 6. u These are respectively named the oil level control range a, b, and c of compressor 6; the oil level control range of oil tank 5 is divided into 4 ranges, with the upper limit S of the oil level in oil tank 5 as the dividing line. u The median oil level S in oil storage tank 5 m The lower limit of the oil level S in oil storage tank 5 d The dividing point is when the oil level S in oil storage tank 5 is less than the lower limit S of the oil level in oil storage tank 5. d The lower limit of the oil level S in oil storage tank 5 d ≤ Oil level S in oil storage tank 5 < Oil level median S in oil storage tank 5 m The median oil level S in oil storage tank 5 m ≤ Oil level S in oil storage tank 5 < Upper limit S of oil level in oil storage tank 5 u The oil level S in oil storage tank 5 is greater than or equal to the upper limit S of the oil level in oil storage tank 5. u These are respectively named as oil level control range 1, oil level control range 2, oil level control range 3, and oil level control range 4 for oil storage tank 5. Each operating condition range corresponds to the unit's operating strategy, such as... Figure 10 The table shows the operating status of various working conditions.

[0125] Figure 10 This is a table for monitoring the operating status of the heat pump unit under various operating conditions. Figure 10 In the diagram, the oil level control range 1, oil level control range 2, oil level control range 3, oil level control range 4 of oil storage tank 5, and the oil level control range a, oil level control range b, and oil level control range c of compressor 6 represent the oil level height monitoring range of oil storage tank 5 and the oil level monitoring range of compressor 6, respectively.

[0126] See Figure 12 In the example shown, for the second control module, the pressure control range of the oil storage tank 5 is divided into three intervals, with the upper pressure limit P of the oil storage tank 5 as the starting point. u The median pressure P of oil storage tank 5 m The lower pressure limit P of oil storage tank 5 d The dividing points are: the gas pressure P of oil storage tank 5 is less than the lower pressure limit P of oil storage tank 5. d The lower pressure limit P of oil storage tank 5 d ≤Gas pressure P of oil storage tank 5 <Median pressure P of oil storage tank 5 m The median pressure P of oil storage tank 5 m The gas pressure P of oil storage tank 5 is less than the upper pressure limit P of oil storage tank 5.u The gas pressure P of oil storage tank 5 is greater than or equal to the upper pressure limit P of oil storage tank 5. u .

[0127] In the solution of this invention, the control logic is as follows: Figure 11 , Figure 12 As shown. See also Figure 11 and Figure 12 In the example shown, compressor 6 starts, and the heat pump unit begins to operate according to the load power until it stabilizes after a period of time t. Here, time t is an empirical value, mainly related to the type of heat pump unit, and is approximately 60 seconds. The first oil level monitor 7 and the second oil level monitor 9 output electrical signals, and the first control module starts operating; the second control module outputs electrical signals from the first oil level monitor 7 and the second oil level monitor 9, and the second control module starts operating.

[0128] In some embodiments, the control unit 104, in conjunction with the current oil level of the compressor 6 and the current oil level of the oil storage device, controls the frequency of the compressor 6 and / or the opening and closing of the first switch to achieve first control of the oil level of the compressor 6, including: a first process of first controlling the oil level of the compressor 6, specifically as follows:

[0129] The control unit 104 is further configured to determine whether the current oil level of the oil storage device is lower than a preset lower limit for the oil level of the oil storage device when the compressor 6 is operating normally. The specific functions and processing of the control unit 104 are further described in step S210.

[0130] The control unit 104 is further configured to, when the compressor 6 is operating normally, if it is determined that the current oil level of the oil storage device is lower than a preset lower limit of the oil level of the oil storage device, control the compressor 6 to run at a preset oil return frequency for a second preset time. The specific functions and processing of this control unit 104 are further described in step S220. The preset oil return frequency is, for example, the oil return frequency f, and the second preset time is, for example, t. c time.

[0131] The control unit 104 is further configured to, when the compressor 6 is operating normally and the current oil level of the oil storage device is less than a preset lower limit for the oil level of the oil storage device, determine whether the current oil level of the oil storage device is greater than a preset median oil level of the oil storage device after controlling the compressor 6 to operate at a preset oil return frequency for a second preset time; the preset median oil level of the oil storage device is greater than the preset lower limit for the oil level of the oil storage device. The specific functions and processing of this control unit 104 are further described in step S230.

[0132] The control unit 104 is further configured to, when the compressor 6 is operating normally and the current oil level of the oil storage device is lower than a preset lower limit for the oil level of the oil storage device, after controlling the compressor 6 to run at a preset oil return frequency for a second preset time, if it is determined that the current oil level of the oil storage device is not greater than a preset median oil level of the oil storage device, then return to continue controlling the compressor 6 to run at the preset oil return frequency for a second preset time. The specific functions and processing of this control unit 104 are further described in step S240.

[0133] Specifically, see Figure 11 In the example shown, after receiving the electrical signals output by the first oil level monitor 7 and the second oil level monitor 9, the first control module needs time t1 after completing each control process before it can process the electrical signals output by the first oil level monitor 7 and the second oil level monitor 9 again. This prevents frequent system control from causing frequent high-low frequency switching of the compressor 6. Here, time t1 is an empirical value. Figure 11 As shown, the control flow of the first control module, namely the joint control logic of compressor 6 and oil tank 5, includes:

[0134] Step 11: After the heat pump unit has been running for time t, input the electrical signals detected by the first oil level monitor 7 and the second oil level monitor 9. Then, execute step 12 to first determine whether the oil level S in the oil storage tank 5 is lower than the lower limit S of the oil level in the oil storage tank 5. d .

[0135] Step 12: First, determine whether the oil level S in oil storage tank 5 is lower than the lower limit S of the oil level in oil storage tank 5. d If the oil level S in oil storage tank 5 is less than the lower limit S of the oil level in oil storage tank 5. d If the oil level S in storage tank 5 is less than the lower limit S of the oil level in storage tank 5, then proceed to step 13; d Then proceed to step 15.

[0136] Step 13: If the oil level S in oil storage tank 5 is less than the lower limit S of the oil level in oil storage tank 5... d Then control compressor 6 to run at the oil return frequency f. c Time, then proceed to step 14.

[0137] Step 14: Determine whether the oil level S in oil storage tank 5 is greater than the median oil level S in oil storage tank 5. m If the oil level S in oil storage tank 5 is less than or equal to the median oil level S in oil storage tank 5 m Then compressor 6 operates at the oil return frequency f. c After a certain period of time, a second assessment will be conducted to determine whether the oil level S in storage tank 5 is greater than the median oil level S in storage tank 5. mIf the oil level S in oil storage tank 5 is greater than the median oil level S in oil storage tank 5... m Then, it is further determined whether the oil level S in oil storage tank 5 is greater than the upper limit S of the oil level in oil storage tank 5. u That is, proceed to step 18.

[0138] In some embodiments, the control unit 104, in conjunction with the current oil level of the compressor 6 and the current oil level of the oil storage device, controls the frequency of the compressor 6 and / or the opening and closing of the first switch to achieve first control of the oil level of the compressor 6. The control unit further includes a second process for performing the first control of the oil level of the compressor 6, as follows:

[0139] The control unit 104 is further configured to, when the compressor 6 is operating normally, determine whether the current oil level of the compressor 6 is lower than the preset lower limit of the oil level of the oil storage device. The specific functions and processing of this control unit 104 are further described in step S310.

[0140] The control unit 104 is further configured to, when the compressor 6 is operating normally and the current oil level of the oil storage device is lower than a preset lower limit for the oil level of the oil storage device, if it is determined that the current oil level of the compressor 6 is lower than the preset lower limit for the oil level of the compressor 6, control the opening and closing of the first switch so that the oil storage device fills the compressor 6 with oil. The specific functions and processing of this control unit 104 are further described in step S320.

[0141] Specifically, such as Figure 11 As shown, the control flow of the first control module, namely the joint control logic of compressor 6 and oil tank 5, includes the following after step 11:

[0142] Step 15: Determine whether the oil level S in oil storage tank 5 is lower than the lower limit S of the oil level in oil storage tank 5. d At that time, the oil level S in oil storage tank 5 shall not be less than the lower limit S of the oil level in oil storage tank 5. d Then continue to determine whether the oil level C of compressor 6 is lower than the lower limit C of the oil level of compressor 6. d If the oil level C of compressor 6 is less than the lower limit C of the oil level of compressor 6. d If the oil level C of compressor 6 is not lower than the lower limit C of oil level C of compressor 6, then proceed to step 16; d Then, it is further determined whether the oil level S in oil storage tank 5 is greater than the upper limit S of the oil level in oil storage tank 5. u That is, proceed to step 18.

[0143] Step 16: If the oil level C of compressor 6 is less than the lower limit C of the oil level of compressor 6... dThen, control the oil storage tank 5 to inject oil into the compressor 6.

[0144] In some embodiments, the control unit 104 controls the opening and closing of the first switch to allow the oil storage device to inject oil into the compressor 6, including:

[0145] The control unit 104 is further configured to control the first switch to open, so that the oil storage device can inject oil into the compressor 6 for a third set time. The specific functions and processing of the control unit 104 are further described in step S410. The third set time is as follows: t s time.

[0146] The control unit 104 is further configured to, after controlling the first switch to open so that the oil storage device can inject oil into the compressor 6 for a third set time, determine whether the current oil level of the compressor 6 is greater than a preset upper limit of the oil level of the compressor 6; the preset upper limit of the oil level of the compressor 6 is greater than a preset lower limit of the oil level of the compressor 6. The specific functions and processing of this control unit 104 are further described in step S420.

[0147] The control unit 104 is further configured to, after controlling the first switch to open so that the oil storage device can fill the compressor 6 with oil for a third set time, if it is determined that the current oil level of the compressor 6 is not greater than the preset upper limit of the oil level of the compressor 6, return to the previous state to continue controlling the first switch to open so that the oil storage device can fill the compressor 6 with oil for a third set time. The specific functions and processing of this control unit 104 are also described in step S430.

[0148] The control unit 104 is further configured to, after controlling the first switch to open so that the oil storage device can fill the compressor 6 with oil for a third set time, if it is determined that the current oil level of the compressor 6 is greater than the preset upper limit of the oil level of the compressor 6, then control the compressor to continue operating normally, and return after a fourth set time, so as to continue to determine whether the current oil level of the oil storage device is less than the preset lower limit of the oil level of the oil storage device while the compressor 6 is operating normally. The specific functions and processing of this control unit 104 are also described in step S440.

[0149] Specifically, such as Figure 11 As shown, the control flow of the first control module, namely the joint control logic of compressor 6 and oil tank 5, includes the following after step 16:

[0150] In step 16, controlling the oil tank 5 to inject oil into the compressor 6 specifically includes: controlling the first solenoid valve 1 to open (i.e., controlling the first solenoid valve 1 to be connected), so that the oil tank 5 injects oil into the compressor 6.s Time, then proceed to step 17.

[0151] Step 17: Determine whether the oil level C of compressor 6 is greater than the upper limit C of the oil level of compressor 6. u If the oil level C of compressor 6 is less than or equal to the upper limit Cu of oil level in compressor 6, then continue adding oil. s Time; if the oil level C of compressor 6 is greater than the upper limit Cu of oil level of compressor 6, then control compressor 6 to operate under normal load.

[0152] In some embodiments, the control unit 104, in conjunction with the current oil level of the compressor 6 and the current oil level of the oil storage device, controls the frequency of the compressor 6 and / or the opening and closing of the first switch to achieve first control of the oil level of the compressor 6. The control unit further includes a third process for first control of the oil level of the compressor 6, as follows:

[0153] The control unit 104 is further configured to, when the compressor 6 is operating normally and the current oil level of the oil storage device is less than a preset lower limit for the oil level of the oil storage device, after controlling the compressor 6 to operate at a preset oil return frequency for a second preset time, determine whether the current oil level of the oil storage device is greater than a preset middle level for the oil storage device; or, when the compressor 6 is operating normally and the current oil level of the oil storage device is less than the preset lower limit for the oil level of the oil storage device, determine whether the current oil level of the oil storage device is greater than a preset upper limit for the oil level of the oil storage device; the preset upper limit for the oil level of the oil storage device is greater than the preset middle level for the oil level of the oil storage device. The specific functions and processing of this control unit 104 are further described in step S510.

[0154] The control unit 104 is further configured to, when the compressor 6 is operating normally and the current oil level of the oil storage device is less than a preset lower limit for the oil level of the oil storage device, after controlling the compressor 6 to run at a preset oil return frequency for a second preset time, if the current oil level of the oil storage device is greater than a preset median oil level of the oil storage device; or, when the compressor 6 is operating normally and the current oil level of the oil storage device is less than the preset lower limit for the oil level of the oil storage device, if it is determined that the current oil level of the compressor 6 is less than the preset lower limit for the oil level of the compressor 6, and if it is determined that the current oil level of the oil storage device is greater than a preset upper limit for the oil level of the oil storage device, then control the opening and closing of the first switch so that the oil storage device fills the compressor 6 with oil. The specific functions and processing of this control unit 104 are also described in step S520. The control unit 104 controls the opening and closing of the first switch to allow the oil storage device to fill the compressor 6 with oil. Specifically, the control unit 104 controls the first switch to open so that the oil storage device fills the compressor 6 with oil for a third set time, such as t. s Time. After controlling the first switch to open so that the oil storage device can fill the compressor 6 with oil for a third set time, the control unit 104 determines whether the current oil level of the compressor 6 is greater than the preset upper limit of the oil level of the compressor 6; if the preset upper limit of the oil level of the compressor 6 is greater than the preset lower limit of the oil level of the compressor 6, the control unit 104, after controlling the first switch to open so that the oil storage device can fill the compressor 6 with oil for a third set time, if it determines that the current oil level of the compressor 6 is not greater than the preset upper limit of the oil level of the compressor 6, then returns to the previous state to continue controlling the first switch to open so that the oil storage device can fill the compressor 6 with oil for a third set time. After the control unit 104 controls the first switch to open so that the oil storage device can fill the compressor 6 with oil for a third set time, if it determines that the current oil level of the compressor 6 is greater than the preset upper limit of the oil level of the compressor 6, it controls the compressor to continue to operate normally. After a fourth set time, it returns to determine whether the current oil level of the oil storage device is less than the preset lower limit of the oil level of the oil storage device while the compressor 6 is operating normally.

[0155] The control unit 104 is further configured to, when the compressor 6 is operating normally and the current oil level of the oil storage device is less than a preset lower limit for the oil level of the oil storage device, after controlling the compressor 6 to run at a preset oil return frequency for a second preset time, if the current oil level of the oil storage device is greater than a preset median oil level of the oil storage device; or, when the compressor 6 is operating normally and the current oil level of the oil storage device is less than the preset lower limit for the oil level of the oil storage device, if it is determined that the current oil level of the compressor 6 is less than the preset lower limit for the oil level of the compressor 6, and if it is determined that the current oil level of the oil storage device is not greater than the preset upper limit for the oil level of the oil storage device, then control the compressor to continue operating normally, and return after a fourth preset time, so as to continue to determine whether the current oil level of the oil storage device is less than the preset lower limit for the oil level of the oil storage device while the compressor 6 is operating normally. The specific functions and processing of this control unit 104 are also described in step S530.

[0156] Specifically, such as Figure 11 As shown, the control flow of the first control module, namely the joint control logic of compressor 6 and oil tank 5, further includes the following after step 14 or step 15:

[0157] Step 18: Determine whether the oil level S in oil storage tank 5 is greater than the upper limit S of the oil level in oil storage tank 5. u If this condition is met, then oil tank 5 will inject oil t into compressor 6. s If the time condition is not met, then proceed to step 17; if the condition is not met, then control compressor 6 to operate under normal load, and then proceed to step 19.

[0158] Step 19: After the compressor 6 is running under normal load, after time t1, the control loop is entered, and the control strategy is run again to process the electrical signals output by the first oil level monitor 7 and the second oil level monitor 9. This completes the control flow of the first control module.

[0159] The present invention addresses the problem that if the oil return process cannot be accurately controlled, resulting in excessively frequent oil return, high-frequency operation of the heat pump unit will affect user comfort, cause additional power consumption, and affect the compressor's lifespan. This is achieved by setting an oil storage tank 5 after the oil-gas separator 4 as a buffer, reducing the number of times the compressor 6 operates at the oil return frequency. Furthermore, through oil level monitoring and related control strategies in the oil storage tank 5, the oil level in the tank is rationally controlled to ensure sufficient oil level when the tank 5 injects oil into the compressor 6.

[0160] In some embodiments, the control unit 104 controls the opening and closing of the second switch and the opening and closing of the gas replenishment switch according to the current gas pressure of the oil storage device, so as to realize the second control of the oil level of the compressor 6, including: a first process of performing the second control of the oil level of the compressor 6, specifically as follows:

[0161] The control unit 104 is further configured to determine whether the current gas pressure of the oil storage device is greater than the preset pressure limit of the oil storage device when the compressor 6 is operating normally. The specific functions and processing of the control unit 104 are further described in step S610.

[0162] The control unit 104 is further configured to, under normal operation of the compressor 6, if it is determined that the current gas pressure of the oil storage device is greater than the preset pressure limit of the oil storage device, control the second switch to open and control the gas replenishment switch to close, for a fifth preset time. The specific functions and processing of this control unit 104 are further described in step S620. The fifth preset time is as follows: t p time.

[0163] The control unit 104 is further configured to, when the compressor 6 is operating normally and the current gas pressure of the oil storage device is greater than a preset upper pressure limit of the oil storage device, after controlling the second switch to open and the gas replenishment switch to close for a fifth preset period of time, determine whether the current gas pressure of the oil storage device is less than a preset median pressure of the oil storage device; the preset median pressure of the oil storage device is less than the preset upper pressure limit of the oil storage device. The specific functions and processing of this control unit 104 are further described in step S630.

[0164] The control unit 104 is further configured to, when the compressor 6 is operating normally and the current gas pressure of the oil storage device is greater than a preset upper pressure limit of the oil storage device, after controlling the second switch to open and the gas replenishment switch to close for a fifth preset time, if it is determined that the current gas pressure of the oil storage device is less than a preset median pressure of the oil storage device, then control the second switch to close and keep the gas replenishment switch closed, and then return to the previous state to continue determining that the current gas pressure of the oil storage device is greater than the preset upper pressure limit of the oil storage device while the compressor 6 is operating normally. The specific functions and processing of this control unit 104 are also described in step S640.

[0165] The control unit 104 is further configured to, when the compressor 6 is operating normally and the current gas pressure of the oil storage device is greater than a preset upper pressure limit of the oil storage device, after controlling the second switch to open and the gas replenishment switch to close for a fifth preset time, if it is determined that the current gas pressure of the oil storage device is not less than a preset median pressure of the oil storage device, then return to the previous state to continue controlling the second switch to open and the gas replenishment switch to close for another fifth preset time. The specific functions and processing of this control unit 104 are further described in step S650.

[0166] Specifically, such as Figure 12 As shown, the pressure control logic for oil storage tank 5 includes:

[0167] Step 21: The second control module determines whether the pressure P of the oil storage tank 5 is greater than the upper pressure limit P of the oil storage tank 5 based on the electrical signal input from the first oil level monitor 7 and the second oil level monitor 9. u If the pressure P of oil storage tank 5 is greater than the upper pressure limit P of oil storage tank 5. u If the pressure P of oil storage tank 5 is too high, then step 22 is executed; if the pressure P of oil storage tank 5 is not greater than the upper pressure limit P of oil storage tank 5, then... u Then proceed to step 24.

[0168] Step 22: Control the opening of the second solenoid valve 2 and the closing of the one-way solenoid valve 3, for a continuous period of time. p After a period of time, it is then determined whether the pressure P of oil storage tank 5 is less than the median pressure P of oil storage tank 5. m That is, proceed to step 23.

[0169] Step 23: Determine whether the pressure P of oil storage tank 5 is less than the median pressure P of oil storage tank 5. m If the pressure P of oil storage tank 5 is less than the median pressure P of oil storage tank 5... m If the pressure in oil tank 5 is still considered high, return to step 22 to continue the operation of opening the second solenoid valve 2 and closing the one-way solenoid valve 3; if the pressure P in oil tank 5 is less than the median pressure P in oil tank 5... m Then, control the closing of the second solenoid valve 2 and the one-way solenoid valve 3, and then return to step 21.

[0170] In some embodiments, the control unit 104 controls the opening and closing of the second switch and the opening and closing of the gas replenishment switch according to the current gas pressure of the oil storage device, so as to realize the second control of the oil level of the compressor 6. The control unit also includes a second process for performing the second control of the oil level of the compressor 6, as follows:

[0171] The control unit 104 is further configured to, under normal operation of the compressor 6, if it is determined that the current gas pressure of the oil storage device is not greater than the preset upper pressure limit of the oil storage device, then determine whether the current gas pressure of the oil storage device is greater than the preset lower pressure limit of the oil storage device; the preset median pressure of the oil storage device is greater than the preset lower pressure limit of the oil storage device. The specific functions and processing of this control unit 104 are further described in step S710.

[0172] The control unit 104 is further configured to, when the compressor 6 is operating normally and the current gas pressure of the oil storage device is not greater than the preset upper pressure limit of the oil storage device, if it is determined that the current gas pressure of the oil storage device is greater than the preset lower pressure limit of the oil storage device, then control the second switch to close and control the gas replenishment switch to open, for a fifth preset time. The specific functions and processing of this control unit 104 are further described in step S720.

[0173] The control unit 104 is further configured to, when the compressor 6 is operating normally and the current gas pressure of the oil storage device is not greater than a preset upper pressure limit of the oil storage device, after controlling the second switch to close and the gas replenishment switch to open for a fifth preset time, determine whether the current gas pressure of the oil storage device is less than a preset median pressure of the oil storage device; the preset median pressure of the oil storage device is less than the preset upper pressure limit of the oil storage device. The specific functions and processing of this control unit 104 are further described in step S730.

[0174] The control unit 104 is further configured to, when the compressor 6 is operating normally and the current gas pressure of the oil storage device is not greater than a preset upper pressure limit of the oil storage device, after controlling the second switch to open and the gas replenishment switch to close for a fifth preset time, if it is determined that the current gas pressure of the oil storage device is less than a preset median pressure of the oil storage device, then control the second switch to close and keep the gas replenishment switch closed, and then return to the previous state to continue determining that the current gas pressure of the oil storage device is greater than the preset upper pressure limit of the oil storage device while the compressor 6 is operating normally. The specific functions and processing of this control unit 104 are also described in step S740.

[0175] The control unit 104 is further configured to, when the compressor 6 is operating normally and the current gas pressure of the oil storage device is not greater than the preset upper pressure limit of the oil storage device, after controlling the second switch to open and the gas replenishment switch to close for a fifth preset time, if it is determined that the current gas pressure of the oil storage device is not less than the preset median pressure of the oil storage device, then return to the previous state to continue controlling the second switch to close and the gas replenishment switch to open for a fifth preset time. The specific functions and processing of this control unit 104 are further described in step S750.

[0176] Specifically, such as Figure 12 As shown, the pressure control logic for oil storage tank 5, after step 21, also includes:

[0177] Step 24: If the pressure P of oil storage tank 5 is not greater than the upper pressure limit P of oil storage tank 5 u Then determine whether the pressure P of oil storage tank 5 is less than the lower pressure limit P of oil storage tank 5. d If the pressure P of oil storage tank 5 is less than the lower pressure limit P of oil storage tank 5. d If the pressure P of oil storage tank 5 is less than the lower pressure limit P of oil storage tank 5, then proceed to step 25; d Then close the second solenoid valve 2 and the one-way solenoid valve 3, and then return to step 21.

[0178] Step 25: Close the second solenoid valve 2, open the one-way solenoid valve 3, and continue for t. p After a certain time, continue to determine whether the pressure P of oil storage tank 5 is greater than the median pressure P of oil storage tank 5. m That is, proceed to step 26.

[0179] Step 26: Determine whether the pressure P of oil storage tank 5 is greater than the median pressure P of oil storage tank 5. m If the pressure P of oil storage tank 5 is not greater than the median pressure P of oil storage tank 5... m Then return to step 25 to continue closing the second solenoid valve 2 and opening the one-way solenoid valve 3 for t. p Time; if the pressure P of oil storage tank 5 is greater than the median pressure P of oil storage tank 5. m If the second solenoid valve 2 and the one-way solenoid valve 3 are closed, then return to step 21. The entire control process is completed.

[0180] The present invention addresses the problems of insufficient gas and low pressure in the oil storage tank 5, making it difficult to inject oil into the compressor 6 without a driving device (such as a pump); and excessive gas pressure in the oil storage tank 5, making it difficult to control the oil injection level. By controlling the pressure of the oil storage tank 5 without installing a return oil driving device, stable oil injection into the compressor is achieved. No power device is needed; the oil storage device (such as the oil storage tank 5) is used to inject oil into the compressor. A one-way solenoid valve (such as one-way solenoid valve 3) is installed between the condenser and the oil storage device (such as the oil storage tank 5), and solenoid valves (such as the first solenoid valve 1 and the second solenoid valve 2) are installed between the oil storage device (such as the oil storage tank 5) and the compressor 6. These are used to replenish or return gas to the oil storage device (such as the oil storage tank 5) to maintain its pressure. Through the gas replenishment device, the return gas bypass device, and the pressure monitoring and related control strategies of the oil storage tank 5, the pressure and volume of the oil storage tank 5 are controlled to ensure sufficient power for the oil storage tank 5 to inject oil into the compressor 6.

[0181] After the control process of the second control module is completed, it processes the electrical signal of the electronic pressure gauge 8 in real time without any interval. Among these processes, the upper limit C of the oil level in the compressor 6 is... u The lower limit of the oil level C of compressor 6 d The upper limit of the oil level S in oil storage tank 5 u The median oil level S in oil storage tank 5 m The lower limit of the oil level S in oil storage tank 5 d The upper pressure limit P of oil storage tank 5 u The median pressure P of oil storage tank 5 m The lower pressure limit P of oil storage tank 5 d Oil return frequency f, time t, time t1, time t c Time t p Time t s All of these are related to the type of heat pump unit; time t, time t1, and time t2 are set according to actual needs. c Time t p Time t s The recommended values ​​are 60s, 120s, 40s, 30s, and 10s.

[0182] In the present invention, the gas pressure and volume control logic of the oil storage device (such as oil storage tank 5) is as follows: the gas volume and gas pressure are monitored by the oil level monitoring device (such as the first oil level monitor 7) and the pressure monitoring device (such as the electronic pressure gauge 8) of the oil storage tank 5, and a suitable control process is used to ensure that the tank volume and pressure meet the operating requirements. The oil return and oil injection control logic of the compressor 6 is as follows: the oil level monitoring device (such as the second oil level monitor 9) of the compressor 6 and the oil level monitoring device (such as the first oil level monitor 7) of the oil storage tank 5 are used to determine the operating range of the system and perform oil return, oil injection, or normal load operation processing. Oil storage tank gas injection bypass: a bypass pipe is set between the oil-gas separation device (such as the oil-gas separator 4) and the condenser inlet, and connected to the oil storage tank 5 through the gas injection switch (such as the one-way solenoid valve 3) to inject gas, ensuring that the internal pressure of the oil storage tank 5 is not lower than the set lower limit pressure. By monitoring the oil level of oil tank 5 and compressor 6 and implementing related control strategies, the oil level of oil tank 5 can be reasonably controlled to ensure sufficient oil level when oil tank 5 injects oil into compressor 6, thus avoiding oil shortage in the heat pump unit and damage to compressor 6. The effect is obvious.

[0183] Since the processing and functions implemented by the device in this embodiment are basically the same as the embodiments, principles and examples of the aforementioned methods, any details not covered in the description of this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0184] The technical solution of this invention, for a heat pump unit consisting of a compressor (e.g., compressor 6), a condenser, an evaporator, an oil-gas separator (e.g., oil-gas separator 4), and an oil storage device (e.g., oil storage tank 5), includes a first switch (e.g., a first solenoid valve 1) installed on the pipeline between the oil return port of the oil storage tank 5 and the suction port of the compressor 6; a second switch (e.g., a second solenoid valve 2) installed on the pipeline between the gas return port of the oil storage tank 5 and the outlet of the evaporator; and a gas supply switch (e.g., a one-way solenoid valve 3) installed on a bypass branch leading from the pipeline between the outlet of the oil-gas separator 4 and the inlet of the condenser to the gas supply port of the oil storage tank 5. When the heat pump unit is running stably after startup, the gas supply is adjusted according to the oil storage tank 5. The system controls the oil level of compressor 6 and the oil level of compressor 6, regulates the time compressor 6 operates at the oil return frequency, and controls the time oil tank 5 replenishes oil to compressor 6. When the oil level of compressor 6 is normal, monitoring the oil level of oil tank 5 allows compressor 6 to operate at high frequency to replenish oil in oil tank 5 as needed. Based on the gas pressure of oil tank 5, the system controls the opening and closing of the first solenoid valve 1, the second solenoid valve 2, and the one-way solenoid valve 3 to ensure that the oil level and gas pressure of oil tank 5, as well as the oil level of compressor 6, are within a reasonable range. This effectively controls the oil level of oil tank 5, ensuring sufficient oil for compressor 6 replenishment and preventing oil shortages that could damage the heat pump unit.

[0185] According to an embodiment of the present invention, a heat pump unit corresponding to a control device for a heat pump unit is also provided. This heat pump unit may include the control device for the heat pump unit described above.

[0186] Since the processing and functions implemented by the heat pump unit in this embodiment are basically the same as those in the embodiments, principles and examples of the aforementioned devices, any details not covered in this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0187] The technical solution of this invention, for a heat pump unit consisting of a compressor (e.g., compressor 6), a condenser, an evaporator, an oil-gas separator (e.g., oil-gas separator 4), and an oil storage device (e.g., oil storage tank 5), includes a first switch (e.g., a first solenoid valve 1) installed on the pipeline between the oil return port of the oil storage tank 5 and the suction port of the compressor 6; a second switch (e.g., a second solenoid valve 2) installed on the pipeline between the gas return port of the oil storage tank 5 and the outlet of the evaporator; and a gas supply switch (e.g., a one-way solenoid valve 3) installed on a bypass branch leading from the pipeline between the outlet of the oil-gas separator 4 and the inlet of the condenser to the gas supply port of the oil storage tank 5. When the heat pump unit is running stably after startup, the system controls the oil level based on the oil level in the oil storage tank 5 and the oil level in the compressor 6. The compressor 6 operates at the oil return frequency for a specified period, and the oil tank 5 is controlled to replenish the compressor 6 with oil. This is achieved by monitoring the oil level in the oil tank 5 when the compressor 6 has a normal oil level, allowing the compressor 6 to operate at high frequency as needed to replenish the oil in the oil tank 5. Based on the gas pressure in the oil tank 5, the opening and closing of the first solenoid valve 1, the second solenoid valve 2, and the one-way solenoid valve 3 are controlled to ensure that the oil level in the oil tank 5, the gas pressure in the oil tank 5, and the oil level in the compressor 6 are all within a reasonable range. This ensures that the compressor 6, when the oil level is normal, replenishes the oil in the oil tank 5 by operating at high frequency as needed, preventing damage to the compressor 6 due to insufficient oil level and ensuring the safe operation of the compressor 6.

[0188] According to an embodiment of the present invention, a storage medium corresponding to a control method for a heat pump unit is also provided, the storage medium including a stored program, wherein, when the program is executed, the device where the storage medium is located is controlled to execute the control method for the heat pump unit described above.

[0189] Since the processing and functions implemented by the storage medium in this embodiment are basically the same as the embodiments, principles and examples of the aforementioned methods, any details not covered in this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0190] The technical solution of this invention, for a heat pump unit consisting of a compressor (e.g., compressor 6), a condenser, an evaporator, an oil-gas separator (e.g., oil-gas separator 4), and an oil storage device (e.g., oil storage tank 5), includes a first switch (e.g., a first solenoid valve 1) installed on the pipeline between the oil return port of the oil storage tank 5 and the suction port of the compressor 6; a second switch (e.g., a second solenoid valve 2) installed on the pipeline between the gas return port of the oil storage tank 5 and the outlet of the evaporator; and a gas supply switch (e.g., a one-way solenoid valve 3) installed on a bypass branch leading from the pipeline between the outlet of the oil-gas separator 4 and the inlet of the condenser to the gas supply port of the oil storage tank 5. When the heat pump unit is running stably after startup, the oil level in the oil storage tank 5 and the compressor... The system monitors the oil level of compressor 6, controls the time during which compressor 6 operates at the oil return frequency, and controls the time during which oil tank 5 replenishes oil to compressor 6. This ensures that, when the oil level of compressor 6 is normal, monitoring the oil level of oil tank 5 allows compressor 6 to replenish oil to oil tank 5 at appropriate high frequencies. Based on the gas pressure in oil tank 5, the system controls the opening and closing of the first solenoid valve 1, the second solenoid valve 2, and the one-way solenoid valve 3 to ensure that the oil level and gas pressure in oil tank 5, as well as the oil level of compressor 6, are within a reasonable range. Thus, through this combined control strategy of monitoring the oil level of compressor 6 and oil tank 5, the system avoids compressor 6 operating at the oil return frequency when the oil level in the compressor body is insufficient, ensuring the safe operation of compressor 6.

[0191] In summary, it is readily understood by those skilled in the art that, without conflict, the aforementioned advantageous methods can be freely combined and superimposed.

[0192] The above description is merely an embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A control method for a heat pump unit, characterized in that, The heat pump unit includes: a compressor (6), a condenser, an evaporator, an oil storage device, and an oil-gas separator (4); the exhaust port of the compressor (6) is connected to the inlet of the condenser after passing through the oil-gas separator (4); the outlet of the evaporator is connected to the suction port of the compressor (6); a first bypass pipe is led out from the oil return port of the oil storage device and connected to the pipe where the suction port of the compressor (6) is located; a second bypass pipe is led out from the oil return port of the oil storage device and connected to the evaporator. The outlet pipeline; a third bypass pipeline is led out from the pipeline between the outlet of the oil-gas separator (4) and the inlet of the condenser, and connected to the gas supply port of the oil storage device; a first switch is provided on the first bypass pipeline, a second switch is provided on the second bypass pipeline, and a gas supply switch is provided on the third bypass pipeline; the oil storage device is provided as a buffer after the oil-gas separator (4), and a one-way valve is provided between the condenser and the oil storage device; the control method of the heat pump unit includes: After the heat pump unit is turned on and runs for a first set time, the oil level monitoring data of the compressor (6) is obtained and recorded as the current oil level of the compressor (6); the oil level monitoring data of the oil storage device is obtained and recorded as the current oil level of the oil storage device; and the gas pressure monitoring data of the oil storage device is obtained and recorded as the current gas pressure of the oil storage device. By combining the current oil level of the compressor (6) and the current oil level of the oil storage device, the frequency of the compressor (6) and / or the opening and closing of the first switch are controlled to achieve the first control of the oil level of the compressor (6); and / or, according to the current gas pressure of the oil storage device, the opening and closing of the second switch and the opening and closing of the gas replenishment switch are controlled to achieve the second control of the oil level of the compressor (6).

2. The control method for a heat pump unit according to claim 1, characterized in that, By combining the current oil level of the compressor (6) and the current oil level of the oil storage device, controlling the frequency of the compressor (6) and / or the opening and closing of the first switch, a first control of the oil level of the compressor (6) is achieved, including: Determine whether the current oil level of the oil storage device is lower than the preset lower limit of the oil level of the oil storage device; If it is determined that the current oil level of the oil storage device is less than the preset lower limit of the oil level of the oil storage device, then the compressor (6) is controlled to run for a second preset time at the preset oil return frequency of the compressor (6); Determine whether the current oil level of the oil storage device is greater than the preset median oil level of the oil storage device; the preset median oil level of the oil storage device is greater than the preset lower limit oil level of the oil storage device. If it is determined that the current oil level of the oil storage device is not greater than the preset median oil level of the oil storage device, then return to continue controlling the compressor (6) to run for a second preset time at the preset oil return frequency of the compressor (6).

3. The control method for a heat pump unit according to claim 2, characterized in that, Combining the current oil level of the compressor (6) and the current oil level of the oil storage device, controlling the frequency of the compressor (6) and / or the opening and closing of the first switch to achieve first control of the oil level of the compressor (6), further comprising: If it is determined that the current oil level of the oil storage device is less than the preset lower limit of the oil level of the oil storage device, then it is determined whether the current oil level of the compressor (6) is less than the preset lower limit of the oil level of the compressor (6). If it is determined that the current oil level of the compressor (6) is less than the preset lower limit of the oil level of the compressor (6), the opening and closing of the first switch is controlled so that the oil storage device can inject oil into the compressor (6).

4. The control method for a heat pump unit according to claim 3, characterized in that, Controlling the opening and closing of the first switch to allow the oil storage device to inject oil into the compressor (6) includes: The first switch is turned on so that the oil storage device injects oil into the compressor (6) for a third set time. Determine whether the current oil level of the compressor (6) is greater than the preset upper limit of the oil level of the compressor (6); the preset upper limit of the oil level of the compressor (6) is greater than the preset lower limit of the oil level of the compressor (6); If it is determined that the current oil level of the compressor (6) is not greater than the preset upper limit of the oil level of the compressor (6), then return to continue to control the first switch to open so that the oil storage device can inject oil into the compressor (6) for a third set time. If it is determined that the current oil level of the compressor (6) is greater than the preset upper limit of the oil level of the compressor (6), the compressor is controlled to continue to operate normally. After a fourth set time, the process returns to continue to determine whether the current oil level of the oil storage device is less than the preset lower limit of the oil level of the oil storage device.

5. The control method for a heat pump unit according to claim 3 or 4, characterized in that, Combining the current oil level of the compressor (6) and the current oil level of the oil storage device, controlling the frequency of the compressor (6) and / or the opening and closing of the first switch to achieve first control of the oil level of the compressor (6), further comprising: If it is determined that the current oil level of the oil storage device is greater than the preset median oil level of the oil storage device, or if it is determined that the current oil level of the compressor (6) is less than the preset lower limit of the oil level of the compressor (6), then it is determined whether the current oil level of the oil storage device is greater than the preset upper limit of the oil level of the oil storage device; the preset upper limit of the oil level of the oil storage device is greater than the preset median oil level of the oil storage device. If it is determined that the current oil level of the oil storage device is greater than the preset upper limit of the oil level of the oil storage device, the opening and closing of the first switch is controlled so that the oil storage device can inject oil into the compressor (6); If it is determined that the current oil level of the oil storage device is not greater than the preset upper limit of the oil level of the oil storage device, the compressor is controlled to continue to operate normally. After a fourth preset time, the process returns to continue to determine whether the current oil level of the oil storage device is less than the preset lower limit of the oil level of the oil storage device.

6. The control method for a heat pump unit according to claim 1, characterized in that, Based on the current gas pressure of the oil storage device, the opening and closing of the second switch and the opening and closing of the gas replenishment switch are controlled to achieve a second control of the oil level of the compressor (6), including: Determine whether the current gas pressure of the oil storage device is greater than the preset pressure limit of the oil storage device; If it is determined that the current gas pressure of the oil storage device is greater than the preset pressure limit of the oil storage device, then the second switch is controlled to open and the gas replenishment switch is controlled to close, for a fifth preset time. Determine whether the current gas pressure of the oil storage device is less than the preset median pressure of the oil storage device; the preset median pressure of the oil storage device is less than the preset upper limit pressure of the oil storage device. If it is determined that the current gas pressure of the oil storage device is less than the preset median pressure of the oil storage device, the second switch is controlled to close, and the gas replenishment switch is kept closed. Then the process is repeated to determine that the current gas pressure of the oil storage device is greater than the preset upper limit pressure of the oil storage device. If it is determined that the current gas pressure of the oil storage device is not less than the preset median pressure of the oil storage device, then return to continue controlling the second switch to open and the gas replenishment switch to close, for a fifth preset time.

7. The control method for a heat pump unit according to claim 6, characterized in that, Based on the current gas pressure of the oil storage device, the opening and closing of the second switch and the opening and closing of the gas replenishment switch are controlled to achieve a second control of the oil level of the compressor (6), and the method further includes: If it is determined that the current gas pressure of the oil storage device is not greater than the preset upper pressure limit of the oil storage device, then it is determined whether the current gas pressure of the oil storage device is greater than the preset lower pressure limit of the oil storage device; the preset median pressure of the oil storage device is greater than the preset lower pressure limit of the oil storage device. If it is determined that the current gas pressure of the oil storage device is greater than the preset lower limit of the oil storage device pressure, then the second switch is controlled to close and the gas replenishment switch is controlled to open, for a fifth preset time. Determine whether the current gas pressure of the oil storage device is less than the preset median pressure of the oil storage device; the preset median pressure of the oil storage device is less than the preset upper limit pressure of the oil storage device. If it is determined that the current gas pressure of the oil storage device is less than the preset median pressure of the oil storage device, the second switch is controlled to close, and the gas replenishment switch is kept closed. Then the process is repeated to determine that the current gas pressure of the oil storage device is greater than the preset upper limit pressure of the oil storage device. If it is determined that the current gas pressure of the oil storage device is not less than the preset median pressure of the oil storage device, then return to continue controlling the second switch to be closed and controlling the gas replenishment switch to be opened, for a fifth preset time.

8. A control device for a heat pump unit, characterized in that, The heat pump unit includes: a compressor (6), a condenser, an evaporator, an oil storage device, and an oil-gas separator (4); the exhaust port of the compressor (6) is connected to the inlet of the condenser after passing through the oil-gas separator (4); the outlet of the evaporator is connected to the suction port of the compressor (6); a first bypass pipe is led out from the oil return port of the oil storage device and connected to the pipe where the suction port of the compressor (6) is located; a second bypass pipe is led out from the oil return port of the oil storage device and connected to the evaporator. The outlet pipeline; a third bypass pipeline is led out from the pipeline between the outlet of the oil-gas separator (4) and the inlet of the condenser, and connected to the gas supply port of the oil storage device; a first switch is provided on the first bypass pipeline, a second switch is provided on the second bypass pipeline, and a gas supply switch is provided on the third bypass pipeline; the oil storage device is provided as a buffer after the oil-gas separator (4), and a one-way valve is provided between the condenser and the oil storage device; the control device of the heat pump unit includes: The acquisition unit is configured to acquire, after the heat pump unit is turned on and running for a first set time, acquire the oil level monitoring data of the compressor (6) and record it as the current oil level of the compressor (6); acquire the oil level monitoring data of the oil storage device and record it as the current oil level of the oil storage device; and acquire the gas pressure monitoring data of the oil storage device and record it as the current gas pressure of the oil storage device. The control unit is configured to combine the current oil level of the compressor (6) and the current oil level of the oil storage device to control the frequency of the compressor (6) and / or the opening and closing of the first switch to achieve a first control of the oil level of the compressor (6); and / or, based on the current gas pressure of the oil storage device, to control the opening and closing of the second switch and the opening and closing of the gas replenishment switch to achieve a second control of the oil level of the compressor (6).

9. A heat pump unit, characterized in that, include: The control device for the heat pump unit as described in claim 8.

10. A storage medium, characterized in that, The storage medium includes a stored program, wherein, when the program is executed, it controls the device containing the storage medium to perform the control method of the heat pump unit as described in any one of claims 1 to 7.

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