Control method of heat pump system

Abstract

The invention relates to the technical field of heat pumps, in particular to a control method of a heat pump system, and aims to solve the problems that how to reasonably adjust the starting number of heating belts so as to solve the problems that inflammable objects such as a cotton quilt of a press are burnt out and oil liquid of the compressor is not sufficiently heated. In order to achieve the purpose, the environment temperature and the actual oil temperature of compressor oil are obtained, the target oil temperature of the compressor oil is determined according to the environment temperature, then the starting number of the heating belts is determined by calculating the first difference value between the target oil temperature and the actual oil temperature, and finally the corresponding number of heating belts are controlled to be started. Therefore, the opening number of the heating belts can be adjusted according to the environment temperature and the actual oil temperature, compressor oil liquid is prevented from being overheated or overcooled, and the problems that flammable objects such as press cotton quilts are burnt out, the flammable objects are layered with refrigerants due to insufficient oil liquid heating, the dissolution rate is reduced, liquid refrigerants boil to take away a large amount of oil due to insufficient oil temperature superheat degree, and an oil film is thinned are solved. And if the friction force is serious, the interior of the compressor is abraded until the compressor loses efficacy.

Description

Technical Field

[0001] The present invention relates to the field of heat pumps, and in particular provides a control method for a heat pump system. Background Art

[0002] When a heat pump system is started, due to the miscibility of the oil and refrigerant in the compressor, a large amount of refrigerant migration will dilute the compressor oil and even reduce its viscosity, significantly reducing its lubrication performance. If the compressor is started in a low-temperature environment at this time, a large amount of liquid refrigerant in the compressor oil will quickly enter the compressor, which can easily cause liquid hammer and even damage the compressor valves, bearings and other components, causing complete compressor failure.

[0003] To address this issue, multiple heating strips are typically installed on the compressor to heat the compressor oil before the compressor starts. However, the number of heating strips activated is fixed and cannot be adjusted. Excessive heating strips can burn flammable items such as press blankets, while insufficient heating strips can lead to insufficient heating of the compressor oil, causing stratification of the refrigerant and oil, a reduced solubility rate, and insufficient oil superheat, leading to the boiling of the liquid refrigerant, which removes a large amount of oil, thinning the oil film, and increasing friction in the compressor. In severe cases, this can even cause internal wear and tear of the compressor, leading to failure.

[0004] Therefore, this field needs a new technical solution to solve the above problems. Summary of the Invention

[0005] In order to solve at least one problem in the prior art, namely, how to reasonably adjust the number of heating belts activated to avoid burning of flammable items such as press quilts and insufficient heating of compressor oil, the present application provides a control method for a heat pump system, the heat pump system comprising a compressor and a plurality of heating belts provided on the compressor, the control method comprising:

[0006] Obtain the ambient temperature X1 and the actual oil temperature Z1 of the compressor oil;

[0007] Determining a target oil temperature Y1 of the compressor oil according to the ambient temperature X1;

[0008] Calculating a first difference T1' between the target oil temperature Y1 and the actual oil temperature Z1;

[0009] Determine the number of heating belts to be turned on according to the first difference T1';

[0010] Based on the number of activations, a corresponding number of the heating belts are controlled to activate.

[0011] In a preferred technical solution of the above control method, there is a positive correlation between the number of the heating belts turned on and the first difference T'.

[0012] In a preferred technical solution of the above control method, after the step of "controlling the start of the corresponding number of the heating tapes", the following steps are further included:

[0013] Every set time, obtain the ambient temperature X2 and the actual oil temperature Z2;

[0014] Determine the target oil temperature Y2 according to the ambient temperature X2;

[0015] Calculate the first difference T2' between the target oil temperature Y2 and the actual oil temperature Z2, and the second difference between the actual oil temperature Z2 at the current time and the actual oil temperature Z1 before the set time;

[0016] Calculate the ratio of the second difference to the actual oil temperature Z1 before the set time to obtain the temperature change rate P;

[0017] Adjust the number of the turned-on heating tapes according to the first difference T2' and the temperature change rate P.

[0018] In a preferred technical solution of the above control method, there is a positive correlation correspondence relationship between the first difference T2' and the temperature change rate P and the number of the turned-on heating tapes respectively.

[0019] In a preferred technical solution of the above control method, after the step of "controlling the start of the corresponding number of the heating tapes", the following steps are further included:

[0020] In response to the received heating instruction, obtain the inlet water temperature T of the condenser

[0021] ,

[0020] , in , , in , ,

[0024] ,

[0023] ,

[0022] , , , in ,

[0027] , in ,

[0026] , , in ,

[0025] , , , and the actual oil temperature Z3;

[0021] According to the inlet water temperature T in and the actual oil temperature Z3, selectively control the start of the compressor.

[0022] In a preferred technical solution of the above control method, the step of "selectively controlling the start of the compressor according to the inlet water temperature T in and the actual oil temperature Z3" further includes:

[0023] Compare the inlet water temperature T in with the first preset inlet water temperature T1;

[0024] When T in > T1, determine the oil temperature superheat degree D according to the actual oil temperature Z3;

[0025] Compare the oil temperature superheat degree D with the first preset oil temperature superheat degree T2;

[0026] When D > T2, control the start of the compressor, and at the same time turn off the turned-on heating tapes.

[0027] In the preferred technical solution of the above control method, the step of "selectively controlling the start of the compressor according to the inlet water temperature T" in and the actual oil temperature Z3 further includes:

[0028] When T in ≤ T1, determine the oil temperature superheat D according to the actual oil temperature Z3;

[0029] Compare the oil temperature superheat D with the second preset oil temperature superheat T3;

[0030] When D > T3, control the start of the compressor, and at the same time turn off the heating belt that has been turned on.

[0031] In the preferred technical solution of the above control method, after the step of "controlling the start of the corresponding number of heating belts", it further includes:

[0032] In response to the received refrigeration instruction, obtain the inlet water temperature T of the condenser in and the actual oil temperature Z3;

[0033] According to the inlet water temperature T in and the actual oil temperature Z3, selectively control the start of the compressor.

[0034] In the preferred technical solution of the above control method, the step of "selectively controlling the start of the compressor according to the inlet water temperature T" in and the actual oil temperature Z3 further includes:

[0035] Compare the inlet water temperature T in with the second preset inlet water temperature T4;

[0036] When T in > T4, determine the oil temperature superheat D according to the actual oil temperature Z3;

[0037] Compare the oil temperature superheat D with the third preset oil temperature superheat T5;

[0038] When D > T5, control the start of the compressor, and at the same time turn off the heating belt that has been turned on.

[0039] In the preferred technical solution of the above control method, the step of "selectively controlling the start of the compressor according to the inlet water temperature T" in and the actual oil temperature Z3 further includes:

[0040] When T ≤ T4, determine the oil temperature superheat D according to the actual oil temperature Z3;

[0041] Compare the oil temperature superheat D with the fourth preset oil temperature superheat T6;

[0042] When D>T6, control the compressor to start and simultaneously turn off the heating belts that have been turned on.

[0043] Those skilled in the art can understand that the control method of the heat pump system of the present application obtains the ambient temperature and the actual oil temperature of the compressor oil, determines the target oil temperature of the compressor oil according to the ambient temperature, calculates the first difference between the target oil temperature and the actual oil temperature, determines the number of heating belts to be turned on according to the first difference, and finally controls the corresponding number of heating belts to start based on the number of heating belts turned on. Thus, it can adjust the number of heating belts according to the ambient temperature and the actual oil temperature of the compressor oil, reduce unnecessary energy consumption, optimize the operating cost, and at the same time prevent the compressor oil from overheating or overcooling, protect the quality and stability of the compressor oil, improve the stability of the entire system, and thus solve the problems that flammable items such as press quilts are burned, and due to insufficient heating of the oil, the oil is stratified from the refrigerant, the dissolution rate is reduced, and the superheat degree of the oil temperature is insufficient, resulting in a large amount of oil being carried away by the boiling of the liquid refrigerant, thinning the oil film, increasing the friction force, and in severe cases, even causing internal wear of the compressor until it fails.

[0044] Further, by setting a positive correlation between the number of heating belts turned on and the first difference, the number of heating belts turned on directly reflects the real-time demand of the compressor, reducing unnecessary energy consumption.

[0045] Further, by adjusting the number of heating belts turned on through the first difference and the temperature change rate, the problems that flammable items such as press quilts are burned or the compressor oil is insufficiently heated are solved, and at the same time, the situation of overheating or overcooling of the compressor oil can be avoided, thus ensuring the safe operation of the compressor.

[0046] Further, by setting the first difference and the temperature change rate to be in a positive correlation with the number of heating belts turned on respectively, the real-time demand of the compressor can be directly reflected, and the problems that flammable items such as press quilts are burned or the compressor oil is insufficiently heated can be avoided.

[0047] Further, in response to heating and cooling, when the inlet water temperature is greater than the first preset inlet water temperature and the oil temperature superheat degree is greater than the first preset oil temperature superheat degree, control the compressor to start and operate in the heating mode, which can improve the heating effect, avoid the problem of internal wear of the compressor caused by low compressor oil temperature, and improve the service life.

[0048] Further, by controlling the compressor to start and operate in the heating mode when the inlet water temperature is less than or equal to the first preset inlet water temperature and the oil temperature superheat degree is greater than the second preset oil temperature superheat degree, the heating effect can also be improved.

[0049] Further, in response to a refrigeration instruction, when the inlet water temperature is greater than the second preset inlet water temperature and the oil temperature superheat is greater than the third preset oil temperature superheat, controlling the compressor to start running in the refrigeration mode can improve the refrigeration effect, avoid the problem of internal wear of the compressor caused by low oil temperature of the compressor oil, and improve the service life.

[0050] Further, by controlling the compressor to start running in the refrigeration mode when the inlet water temperature is less than the second preset inlet water temperature and the oil temperature superheat is greater than the fourth preset oil temperature superheat, the refrigeration effect can be improved, the problem of internal wear of the compressor caused by low oil temperature of the compressor oil can be avoided, and the service life can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. In the drawings:

[0052] Figure 1 is a flowchart of the control method of the heat pump system of the present application;

[0053] Figure 2 is a logic diagram of another possible implementation manner of the control method of the heat pump system of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0054] The preferred embodiments of the present application will be described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principle of the present application and are not intended to limit the protection scope of the present application. For example, although the following embodiments describe the various steps in a sequential manner, those skilled in the art can understand that in order to achieve the effects of this embodiment, the different steps do not have to be executed in such an order, and they can be executed simultaneously (in parallel) or in a reversed order, and these simple changes are all within the protection scope of the present application.

[0055] First, refer to Figure 1 , and describe the control method of the heat pump system of the present application. Among them, Figure 1 is a flowchart of the control method of the heat pump system of the present application.

[0056] As Figure 1 shown, in order to solve the problem of how to reasonably adjust the number of heating belts turned on, avoid burning of flammable items such as press quilts, and insufficient heating of the compressor oil, the heat pump system of the present application includes a compressor and a plurality of heating belts provided on the compressor, and each heating belt can be independently controlled to be turned on or off.

[0057] As Figure 1 shown, on the premise of the above setting method, the control method of the heat pump system of the present application includes:

[0058] S101. Obtain the ambient temperature X1 and the actual oil temperature Z1 of the compressor oil. For example, a first temperature sensor for obtaining the ambient temperature and a second temperature sensor for obtaining the actual oil temperature of the compressor oil may be configured, and the ambient temperature and the actual oil temperature of the compressor oil may be detected by the first temperature sensor and the second temperature sensor.

[0059] S102. Determine a target oil temperature Y1 of the compressor oil based on the ambient temperature X1. For example, after obtaining the ambient temperature, the target oil temperature of the compressor oil can be determined based on a relationship between the ambient temperature and the target oil temperature of the compressor oil, such as a comparison table or an empirical formula. For example, when the ambient temperature is high, the target oil temperature of the compressor oil is high, and when the ambient temperature is low, the target oil temperature of the compressor oil is low.

[0060] S103 , calculating a first difference T1 ′ between the target oil temperature Y1 and the actual oil temperature Z1 ; for example, after obtaining the target oil temperature and the actual oil temperature, the first difference is obtained by calculating the difference between the target oil temperature and the actual oil temperature.

[0061] S104. Determine the number of heating belts to be turned on based on the first difference T1'. For example, after obtaining the first difference, the number of heating belts to be turned on is determined based on a correspondence between the first difference and the number of heating belts to be turned on, such as a comparison table or an empirical formula. For example, when the first difference is large, the number of heating belts to be turned on is large, and when the first difference is small, the number of heating belts to be turned on is small.

[0062] Based on the number of heaters that are turned on, a corresponding number of heaters are controlled to start. For example, after determining the number of heaters that are turned on, a corresponding number of heaters are controlled to start to heat the compressor oil.

[0063] The present application obtains the ambient temperature and the actual oil temperature of the compressor oil, determines the target oil temperature of the compressor oil based on the ambient temperature, calculates the first difference between the target oil temperature and the actual oil temperature, and determines the number of heating belts to be turned on based on the first difference. Finally, based on the number of turning on, the corresponding number of heating belts are controlled to start, so that the number of heating belts can be adjusted according to the ambient temperature and the actual oil temperature of the compressor oil, thereby reducing unnecessary energy consumption and optimizing operating costs. At the same time, it can also prevent the compressor oil from overheating or overcooling, protect the quality and stability of the oil, and improve the stability of the entire system, thereby solving the problems of flammable items such as compressor quilts being burned, and the problem of insufficient heating of the oil causing it to stratify with the refrigerant, reduced solubility, and insufficient oil superheat causing the liquid refrigerant to boil and take away a large amount of oil, making the oil film thinner and the friction greater. In severe cases, it may even cause internal wear of the compressor until failure.

[0064] The preferred implementation of the control method of the heat pump system of the present application is introduced below.

[0065] In one implementation, there is a positive correlation between the number of heating belts turned on and the first difference T1'.

[0066] It should be noted that a larger first difference T1' indicates a larger difference between the target oil temperature Y1 of the compressor oil and its actual oil temperature Z1, and a lower actual oil temperature Z1 of the compressor oil. At this time, a larger number of heating belts need to be turned on to heat the compressor oil. When the first difference T1' is small, it means that the difference between the target oil temperature Y1 of the compressor oil and its actual oil temperature Z1 is small, and the actual oil temperature Z1 of the compressor oil is relatively high. At this time, a small number of heating belts need to be turned on to heat the compressor oil.

[0067] For example, taking the number of heating belts as 3 as an example. When T1'≥10°C, it means that the actual oil temperature Z1 of the compressor oil is low. At this time, control 3 heating belts to be turned on simultaneously to heat the compressor oil. When 10°C>T1'≥5°C, it means that the actual oil temperature Z1 of the compressor oil is relatively high. At this time, 2 heating belts can be controlled to be turned on to heat the compressor oil. When 5°C>T1'≥1°C, it means that the actual oil temperature Z1 of the compressor is high. At this time, 1 heating belt can be controlled to be turned on to heat the compressor oil. When T1'<1°C, it means that the actual oil temperature Z1 of the compressor oil is close to the target temperature Y1, and the compressor oil reaches the starting temperature. At this time, there is no need to turn on the heating belt.

[0068] In one implementation, after the step of "controlling the start of the corresponding number of heating belts", it further includes:

[0069] Every set time, obtain the ambient temperature X2 and the actual oil temperature Z2;

[0070] Determine the target oil temperature Y2 according to the ambient temperature X2;

[0071] Calculate the first difference T2' between the target oil temperature Y2 and the actual oil temperature Z2, and the second difference between the actual oil temperature Z2 at the current time and the actual oil temperature Z1 before the set time;

[0072] Calculate the ratio of the second difference to the actual oil temperature Z1 before the set time to obtain the temperature change rate P;

[0073] Adjust the number of heating belts turned on according to the first difference T2' and the temperature change rate P.

[0074] Since the ambient temperature and the actual oil temperature are constantly changing, it is necessary to re-obtain the ambient temperature and the actual oil temperature at every set time interval, calculate the first difference T2' and the temperature change rate P, and accordingly adjust the number of heating belts turned on to avoid overheating or overcooling of the compressor oil, and solve the problems that flammable items such as compressor quilts are burned, or due to insufficient oil heating, the oil is stratified from the refrigerant, the dissolution rate is reduced, and the superheat of the oil temperature is insufficient, resulting in the boiling of the liquid refrigerant and carrying away a large amount of oil, thinning the oil film, increasing the friction, and in severe cases, even causing internal wear of the compressor until it fails.

[0075] It should be noted that there is no limitation on the set time in this application. It can be 5 minutes, 10 minutes or other time, as long as the number of heating belts turned on can be adjusted according to the first difference T2' and the temperature change rate P before the compressor starts. Taking the set time of 10 minutes as an example, the actual oil temperature Z2 at the current time and the actual oil temperature Z1 before the set time are described. The actual oil temperature Z2 at the current time refers to the actual oil temperature obtained after 10 minutes of the set time, and the actual oil temperature Z1 before the set time refers to the actual oil temperature obtained 10 minutes ago without the 10-minute set time. In addition, the temperature change rate can directly be the ratio of the second difference to the actual oil temperature Z1 before the set time, or it can also be the value of the ratio multiplied by 100%.

[0076] Furthermore, the control method further includes:

[0077] There is a positive correlation correspondence relationship between the first difference T2' and the temperature change rate P and the number of heating belts turned on respectively.

[0078] It should be noted that a relatively large first difference T2' indicates that the target oil temperature Y2 and the actual oil temperature Z2 have a relatively large difference, and the actual oil temperature is still relatively low after the set time. A relatively large temperature change rate P indicates that the temperature of the compressor oil has risen significantly after the set time. Therefore, when the values of both the first difference T2' and the temperature change rate P are relatively large, some additional heating belts can be started on the basis of the originally turned-on heating belts to heat the compressor oil, avoiding problems such as the oil being stratified from the refrigerant, the dissolution rate being reduced, and the superheat of the oil temperature being insufficient, resulting in the boiling of the liquid refrigerant and carrying away a large amount of oil, thinning the oil film, increasing the friction, and in severe cases, even causing internal wear of the compressor until it fails. When the first difference T2' is relatively small, it indicates that after the set time, the actual oil temperature Z2 of the compressor oil quickly approaches the target oil temperature Y2. A relatively small temperature change rate P indicates that after the set time, the temperature of the compressor oil rises slowly and the actual oil temperature Z2 reaches a certain level. Therefore, in order to avoid burning of flammable items such as compressor quilts, when the values of both the first difference T2' and the temperature change rate P are relatively small, some of the originally turned-on heating belts can be turned off.

[0079] For example, taking the set time as 10 min and the number of heating tapes as 3 as an example for illustration. After controlling 2 heating tapes to start for 10 min, continue to obtain the ambient temperature X2 and the actual oil temperature Z2, and determine the target oil temperature Y2 according to the ambient temperature X2. Calculate the first difference T2' between the target oil temperature Y2 and the actual oil temperature Z2, and the second difference between the actual oil temperature Z2 at the current time and the actual oil temperature Z1 before the set time. Calculate the ratio of the second difference to the actual oil temperature Z1 before the set time to obtain the temperature change rate P. When T2' > 5°C and P > 50%, it indicates that the values of both the first difference T2' and the temperature change rate P are relatively large, and the temperature of the compressor oil is still relatively low after the set time. At this time, another heating tape can be started, that is, 3 heating tapes are turned on simultaneously to heat the compressor oil. When T2' > 5°C and P ≤ 50%, or T2' ≤ 5°C and P > 50%, 2 heating tapes can continue to be started to heat the compressor oil. When 5°C ≥ T2' > 2°C and 50% ≥ P > 20%, it indicates that the values of the first difference T2' and the temperature change rate P are relatively low, and the temperature of the compressor oil is relatively high and can quickly reach the target temperature. At this time, one heating tape can be turned off, that is, 1 heating tape remains on to continue heating the compressor oil. When 5°C ≥ T2' > 2°C and P ≤ 20%, or T2' ≤ 2°C and 50% ≥ P > 20%, or T2' ≤ 2°C and P ≤ 20%, it indicates that the value of the first difference T2' and / or the temperature change rate P is small, and the compressor has reached the starting temperature, and all heating tapes can be controlled to turn off.

[0080] In one implementation, after the step of "controlling the start of the corresponding number of heating tapes", it further includes:

[0081] In response to the received heating instruction, obtain the inlet water temperature T of the condenser in and the actual oil temperature Z3;

[0082] According to the inlet water temperature T in and the actual oil temperature Z3, selectively control the start of the compressor.

[0083] It should be noted that when the heat pump system receives the heating instruction, it is necessary to determine at this time whether the inlet water temperature T in and the actual oil temperature Z3 meet the conditions for starting the compressor, and selectively control the start of the compressor according to the judgment result.

[0084] Furthermore, the step of "selectively controlling the start of the compressor according to the inlet water temperature T in and the actual oil temperature Z3" further includes:

[0085] Compare the inlet water temperature T in with the first preset inlet water temperature T1;

[0086] When T in > T1, determine the oil temperature superheat D according to the actual oil temperature Z3;

[0087] Compare the oil temperature superheat D with the first preset oil temperature superheat T2;

[0088] When D > T2, control the compressor to start, and at the same time turn off the heated belt that has been turned on.

[0089] For example, take the first preset inlet water temperature T1 as 30 °C and the first preset oil temperature superheat T2 as 5 °C for illustration. When T in > 30 °C, it indicates that the inlet water temperature T of the condenser in is relatively high, and the inlet water temperature T in has a positive correlation with the oil temperature superheat when the compressor is running. And the oil temperature superheat is the difference between the actual oil temperature and the saturation temperature of the exhaust pressure. Therefore, there is a positive correlation between the actual oil temperature of the compressor and the oil temperature superheat. When T in > 30 °C, it is necessary to compare the actual oil temperature Z3 with the first preset oil temperature superheat T2. When D > 5 °C, it indicates that the superheat of the compressor oil is relatively high, meeting the starting conditions of the compressor, and control the compressor to start and operate in the heating mode. In addition, since the compressor meets the starting conditions, when controlling the compressor to start, control the heated belt that has been turned on to turn off, which can avoid burning of flammable items such as the compressor quilt, and at the same time can also avoid the performance of the compressor oil being affected by the too high oil temperature of the compressor and the normal operation of the compressor.

[0090] In one embodiment, the step of "selectively controlling the compressor to start according to the inlet water temperature T in and the actual oil temperature Z3" further includes:

[0091] When T in ≤ T1, determine the oil temperature superheat D according to the actual oil temperature Z3;

[0092] Compare the oil temperature superheat D with the second preset oil temperature superheat T3;

[0093] When D > T3, control the compressor to start, and at the same time turn off the heated belt that has been turned on.

[0094] For example, take the first preset inlet water temperature T1 as 30 °C and the second preset oil temperature superheat T3 as 3 °C for illustration. When T in ≤ 30 °C, it indicates that the inlet water temperature T of the condenser in is relatively low, and the lower the inlet water temperature T in is, the lower the oil temperature superheat D when starting the compressor. Therefore, T inIf it is ≤ 30°C, the oil temperature superheat D is determined according to the actual oil temperature Z3, and the size of the oil temperature superheat D and the second preset oil temperature superheat T3 is compared. When D > 3°C and the compressor starting condition is satisfied, the compressor is controlled to start and operate in the heating mode. In addition, when controlling the start of the compressor, it is also necessary to control the turned-on heating belts to turn off to avoid energy waste and the problem of burning of flammable items such as the compressor cotton quilt.

[0095] In one embodiment, in response to the received refrigeration instruction, after the step of "controlling the start of the corresponding number of heating belts", it further includes:

[0096] Obtain the inlet water temperature T of the condenser in and the actual oil temperature Z3;

[0097] According to the inlet water temperature T in and the actual oil temperature Z3, selectively control the start of the compressor.

[0098] It should be noted that when the heat pump system receives a refrigeration instruction, it is necessary to determine whether the inlet water temperature T in and the actual oil temperature Z3 meet the compressor starting condition, and selectively control the start of the compressor according to the judgment result.

[0099] In one embodiment, the step of "selectively controlling the start of the compressor according to the inlet water temperature T in and the actual oil temperature Z3" further includes:

[0100] Compare the inlet water temperature T in with the second preset inlet water temperature T4;

[0101] When T in > T4, determine the oil temperature superheat D according to the actual oil temperature Z3;

[0102] Compare the oil temperature superheat D with the third preset oil temperature superheat T5;

[0103] When D > T5, control the compressor to start.

[0104] For example, taking the second preset inlet water temperature T4 as 15°C and the third preset oil temperature superheat T5 as 5°C as an example. When T in > 15°C, it indicates that the inlet water temperature T of the condenser in is relatively high, and the higher the inlet water temperature T in , the higher the oil temperature superheat D when starting the compressor to operate. Therefore, when T inWhen the temperature is higher than 15°C, determine the superheat degree D of the oil temperature according to the actual oil temperature Z3, and compare the superheat degree D of the oil temperature with the third preset superheat degree T5 of the oil temperature. When D > 5°C, it indicates that the superheat degree of the oil temperature is relatively high, and the compressor meets the starting condition, then control the compressor to start and operate in the refrigeration mode. Additionally, when controlling the compressor to start, it is necessary to control the turned-on heating belt to turn off to avoid energy waste.

[0105] Further, the step of "selectively controlling the compressor to start according to the inlet water temperature T in and the actual oil temperature Z3" further includes:

[0106] When T in ≤ T4, determine the superheat degree D of the oil temperature according to the actual oil temperature Z3;

[0107] Compare the superheat degree D of the oil temperature with the fourth preset superheat degree T6 of the oil temperature;

[0108] When D > T6, control the compressor to start.

[0109] Wherein, the inlet water temperature T in has a positive correlation with the superheat degree D of the oil temperature when the compressor operates. Here, the fourth preset superheat degree T6 of the oil temperature can be less than the second preset superheat degree T5 of the oil temperature, or can be equal to the second preset superheat degree T5 of the oil temperature. As long as the superheat degree D of the oil temperature is greater than the fourth preset superheat degree T6, the compressor meets the starting condition.

[0110] For example, taking the second preset inlet water temperature T4 as 15°C and the fourth preset superheat degree T6 of the oil temperature as 3°C as an example for illustration. When T in ≤ 15°C, it indicates that the inlet water temperature T of the condenser in is relatively low, and when the inlet water temperature T in is low, the superheat degree D of the oil temperature when the compressor operates is low. Therefore, when T in ≤ 15°C, determine the superheat degree D of the oil temperature according to the actual oil temperature Z3, and compare the superheat degree D of the oil temperature with the fourth preset superheat degree T6 of the oil temperature. When D > 3°C, it indicates that the compressor meets the starting condition, and at this time, control the compressor to start. Additionally, when controlling the compressor to start, it is necessary to control the turned-on heating belt to turn off to avoid burning of flammable items such as the compressor cotton quilt.

[0111] Next, in combination with Figure 2 , a possible operation process of the control method of the heat pump system of the present application will be briefly described. Figure 2 is a logic diagram of a possible implementation manner of the control method of the heat pump system of the present application.

[0112] S201. In response to the received heating instruction, obtain the ambient temperature X1 and the actual oil temperature Z1 of the compressor oil, and then execute S202.

[0113] S202. Determine the target oil temperature Y1 of the compressor oil based on the ambient temperature X1, and then execute S203.

[0114] S203. Calculate the first difference T1' between the target oil temperature Y1 and the actual oil temperature Z1, and execute S205.

[0115] S204. Determine the number of heating belts to be turned on according to the positive correlation between the first difference T1' and the number of heating belts turned on, and then execute S210.

[0116] S205. Based on the number of heating belts turned on, control the corresponding number of heating belts to start, and then execute S206.

[0117] S206. Obtain the start time of the heating belt, and then execute S207.

[0118] S207. Compare the start time with the set time; if the start time is greater than or equal to the set time, execute S208, otherwise execute S206.

[0119] S208. Obtain the ambient temperature X2 and the actual oil temperature Z2, and then execute S209.

[0120] S209. Determine the target oil temperature Y2 according to the ambient temperature X2, and then execute S210.

[0121] S210. Calculate the first difference T2' between the target oil temperature Y2 and the actual oil temperature Z2, and the second difference between the actual oil temperature Z2 at the current time and the actual oil temperature Z1 before the set time, and execute S211.

[0122] S211. Calculate the ratio of the second difference to the actual oil temperature Z1 before the set time to obtain the temperature change rate P, and then execute S212.

[0123] S212. Adjust the number of heating belts according to the positive correlation between the first difference T2' and the temperature change rate P and the number of heating belts turned on, and then execute S213.

[0124] S213. Obtain the inlet water temperature T of the condenser in and the actual oil temperature Z3, and then execute S214.

[0125] S214. Judge whether T in > 30°C holds; if it holds, execute S214, otherwise execute S215.

[0126] S215. Determine the oil temperature superheat D according to the actual oil temperature Z3, and then execute S216.

[0127] S216. Determine whether D > 5°C holds; if it holds, execute S217, otherwise execute S212.

[0128] S217. Control the compressor to start running in the heating mode, and at the same time turn off the already - turned - on heating belt.

[0129] S218. Determine the oil - temperature superheat D according to the actual oil temperature Z3, and then execute S219.

[0130] S219. Determine whether D > 3°C holds; if it holds, execute S217, otherwise execute S212.

[0131] Those skilled in the art can understand that although some of the embodiments described herein include certain features included in other embodiments rather than other features, the combination of the features of different embodiments means that it is within the scope of this application and forms different embodiments. For example, in the claims of this application, any one of the claimed embodiments can be used in any combination.

[0132] So far, the technical solutions of this application have been described in conjunction with the preferred embodiments shown in the drawings. However, it is easy for those skilled in the art to understand that the protection scope of this application is obviously not limited to these specific embodiments. Without departing from the principle of this application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of this application.

Claims

1. A control method for a heat pump system, characterized in that, The heat pump system includes a compressor and a plurality of heating belts provided on the compressor. The control method includes: Obtain the ambient temperature X1 and the actual oil temperature Z1 of the compressor oil. Determine the target oil temperature Y1 of the compressor oil according to the ambient temperature X1. Calculate the first difference T1' between the target oil temperature Y1 and the actual oil temperature Z1. Determine the number of activated heating belts according to the first difference T1'. Based on the number of activations, control the activation of the corresponding number of the heating belts.

2. The control method according to claim 1, wherein There is a positive correlation corresponding relationship between the number of activated heating belts and the first difference T1'.

3. The control method according to claim 1, wherein After the step of "controlling the activation of the corresponding number of the heating belts", it further includes: Every set time, obtain the ambient temperature X2 and the actual oil temperature Z2. Determine the target oil temperature Y2 according to the ambient temperature X2. Calculate the first difference T2' between the target oil temperature Y2 and the actual oil temperature Z2, and the second difference between the actual oil temperature Z2 at the current time and the actual oil temperature Z1 before the set time. Calculate the ratio of the second difference to the actual oil temperature Z1 before the set time to obtain the temperature change rate P. Adjust the number of activated heating belts according to the first difference T2' and the temperature change rate P.

4. The control method according to claim 3, wherein There are positive correlation corresponding relationships between the first difference T2' and the temperature change rate P and the number of activated heating belts respectively.

5. The control method according to claim 1, characterized in that After the step of "controlling the activation of the corresponding number of the heating belts", it further includes: In response to the received heating instruction, obtain the inlet water temperature T of the condenser in and the actual oil temperature Z3; According to the inlet water temperature T in and the actual oil temperature Z3, selectively control the start of the compressor.

6. The control method according to claim 5, characterized in that, "According to the inlet water temperature T in and the actual oil temperature Z3, selectively controlling the startup of the compressor" further includes the steps of: Compare the inlet water temperature T in with the first preset inlet water temperature T1; When T in > T1, the oil temperature superheat degree D is determined according to the actual oil temperature Z3; Compare the oil temperature superheat D with the first preset oil temperature superheat T2. When D>T2, control the start of the compressor and at the same time turn off the activated heating belts.

7. The control method according to claim 6, characterized in that, "According to the inlet water temperature T in and the actual oil temperature Z3, selectively controlling the startup of the compressor", the steps further include: When T in ≤ T1, determine the oil temperature superheat degree D according to the actual oil temperature Z3; Compare the oil temperature superheat D with the second preset oil temperature superheat T3. When D>T3, control the start of the compressor and at the same time turn off the activated heating belts.

8. The control method according to claim 1, wherein After the step of "controlling the activation of the corresponding number of the heating belts", it further includes: In response to the received refrigeration instruction, obtain the inlet water temperature T of the condenser in and the actual oil temperature Z3; According to the inlet water temperature T in and the actual oil temperature Z3, selectively control the startup of the compressor.

9. The control method according to claim 8, characterized in that "According to the inlet water temperature T in and the actual oil temperature Z3, the step of selectively controlling the start of the compressor further includes: Compare the inlet water temperature T in with the second preset inlet water temperature T4; When T in > T4, determine the oil temperature superheat D according to the actual oil temperature Z3; Compare the oil temperature superheat D with the third preset oil temperature superheat T5. When D>T5, control the start of the compressor and at the same time turn off the activated heating belts.

10. The control method according to claim 9, characterized in that, "According to the inlet water temperature T in and the actual oil temperature Z3, selectively controlling the start of the compressor" further includes the steps of: When T≤T4, determine the oil temperature superheat D according to the actual oil temperature Z3. Compare the oil temperature superheat D with the fourth preset oil temperature superheat T6. When D>T6, control the start of the compressor and at the same time turn off the activated heating belts.

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