Control method of air conditioning system

Abstract

The invention relates to the technical field of air conditioning systems, particularly provides a control method of an air conditioning system, and aims to solve the problem of how to improve the anti-condensation effect. In order to achieve the purpose, the control method of the air conditioning system comprises the steps that the operation opening degree of a valve body is adjusted according to the first temperature difference between the internal temperature of a first frequency converter and the first refrigerant temperature, and the operation opening degree of the valve body is adjusted according to the second temperature difference between the internal temperature of a second frequency converter and the second refrigerant temperature; the difference value change rate between the two temperature differences is calculated, and the operation rotating speed of the compressor is adjusted according to the size relation between the difference value change rate and a preset change rate threshold value, so that the refrigerant flow and the circulating speed in the heat exchange pipe can be adjusted, the refrigerant temperature and the internal temperature of the frequency converter are changed, and the difference value between the internal temperature of the frequency converter and the refrigerant temperature is reduced; and the phenomenon that the surface of the heat exchange tube is condensed due to the fact that the temperature difference between the two is too large is avoided, and safety and reliability of an air conditioning system are enhanced.

Description

Technical Field

[0001] The present invention relates to the field of air-conditioning systems, and specifically provides a control method for an air-conditioning system. Background Art

[0002] As the core component of an air-conditioning system, the frequency converter plays a crucial role, and its stable operation is the basis for ensuring the efficient and reliable operation of the entire air-conditioning system. However, during operation, the frequency converter easily generates a large amount of heat energy. If this heat cannot be dissipated in time, it will lead to increased loss of internal components and even failures, affecting the stable operation of the air-conditioning system. To reduce the temperature of the frequency converter, heat exchange tubes are usually arranged inside the frequency converter, and the heat generated by the frequency converter is absorbed and carried away through the circulating flow of the refrigerant. However, when there is a large temperature difference between the refrigerant inside the heat exchange tube and the inside of the frequency converter, condensation is extremely likely to form on the surface of the heat exchange tube, making the frequency converter prone to short circuits.

[0003] To solve the problem of condensation on the surface of the condensation tube, a valve body is usually set at the inlet of the heat exchange tube into the frequency converter, and the opening degree of the valve body is adjusted to change the temperature of the refrigerant inside the condensation tube. Although this method can solve the problem of condensation on the heat exchange tube to a certain extent, the effect is not ideal.

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

[0005] To solve at least one problem in the prior art, that is, to solve the problem of how to improve the anti-condensation effect. The present application provides a control method for an air-conditioning system. The air-conditioning system includes a frequency converter and a heat exchange tube. The heat exchange tube penetrates through the frequency converter and a valve body is provided at its inlet located inside the frequency converter. The control method includes:

[0006] Adjust the operating opening degree of the valve body according to the first temperature difference between the internal temperature of the first frequency converter and the first refrigerant temperature at the inlet of the frequency converter;

[0007] After adjusting the operating opening degree of the valve body,

[0008] Obtain the second refrigerant temperature and the second internal temperature of the frequency converter at the inlet of the frequency converter, and calculate the second temperature difference between the two;

[0009] Calculate the difference change rate between the first temperature difference and the second temperature difference;

[0010] Compare the size of the difference change rate with a preset change rate threshold;

[0011] Based on the comparison result, selectively adjust the operating speed of the compressor.

[0012] In the preferred technical solution of the above control method, the step of "adjusting the operating opening of the valve body according to the first temperature difference between the internal temperature of the first frequency converter and the first refrigerant temperature at the inlet of the frequency converter" further includes:

[0013] When the first temperature difference is greater than or equal to a preset temperature difference, reduce the operating opening of the valve body.

[0014] In the preferred technical solution of the above control method, the step of "selectively adjusting the operating speed of the compressor based on the comparison result" further includes:

[0015] When the rate of change of the difference is greater than or equal to the preset rate-of-change threshold, reduce the operating speed of the compressor.

[0016] In the preferred technical solution of the above control method, before the step of "calculating the rate of change of the difference between the first temperature difference and the second temperature difference", it further includes:

[0017] Compare the second temperature difference with the preset temperature difference;

[0018] When the second temperature difference is greater than or equal to the preset temperature difference, calculate the rate of change of the difference between the first temperature difference and the second temperature difference.

[0019] In the preferred technical solution of the above control method, the control method further includes:

[0020] When the second temperature difference is less than the preset temperature difference, increase the operating opening of the valve body.

[0021] In the preferred technical solution of the above control method, before, at the same time as, or after the step of "reducing the operating opening of the valve body", it further includes:

[0022] Increase the operating speed of the fan in the frequency converter.

[0023] In the preferred technical solution of the above control method, the control method further includes:

[0024] When the first temperature difference is less than the preset temperature difference, increase the operating opening of the valve body.

[0025] In the preferred technical solution of the above control method, the step of "selectively adjusting the operating speed of the compressor based on the comparison result" further includes:

[0026] When the rate of change of the difference is greater than or equal to the preset rate-of-change threshold, increase the operating speed of the compressor.

[0027] In the preferred technical solution of the above control method, after the step of "increasing the operating speed of the compressor", it includes:

[0028] Control the fan to stop working.

[0029] In a preferred technical solution of the above control method, before the step of "calculating the rate of change of the difference between the first temperature difference and the second temperature difference", the following steps are further included:

[0030] Compare the second temperature difference with the preset temperature difference;

[0031] When the second temperature difference is less than the preset temperature difference, calculate the rate of change of the difference between the first temperature difference and the second temperature difference.

[0032] In a preferred technical solution of the above control method, the control method further includes:

[0033] When the second temperature difference is greater than or equal to the preset temperature difference, reduce the operating opening of the valve body.

[0034] In a preferred technical solution of the above control method, before, at the same time as, or after the step of "increasing the operating opening of the valve body", the following steps are further included:

[0035] Reduce the operating speed of the fan.

[0036] Those skilled in the art can understand that the control method of the air conditioning system of the present application adjusts the operating opening of the valve body according to the first temperature difference between the internal temperature of the first frequency converter and the first refrigerant temperature, and calculates the rate of change of the difference between the two temperature differences according to the second temperature difference between the internal temperature of the second frequency converter and the second refrigerant temperature after the operating opening of the valve body is adjusted, and adjusts the operating speed of the compressor according to the magnitude relationship between the rate of change of the difference and the preset rate of change threshold, so as to be able to adjust the refrigerant flow rate and circulation speed in the heat exchange tube, change the refrigerant temperature and the internal temperature of the frequency converter, reduce the difference between the internal temperature of the frequency converter and the refrigerant temperature, improve the anti-condensation effect, avoid the condensation phenomenon on the surface of the heat exchange tube due to the too large temperature difference between the two, and enhance the safety and reliability of the air conditioning system.

[0037] Further, when the first temperature difference is greater than or equal to the preset temperature difference, by reducing the operating opening of the valve body, the refrigerant flow rate can be reduced, so that the temperature of the refrigerant is increased, which helps to reduce the difference between the internal temperature of the frequency converter and the refrigerant temperature and avoid condensation on the surface of the condensation tube.

[0038] Further, when the rate of change of the difference is greater than or equal to the preset rate of change threshold, by reducing the operating speed of the compressor, the refrigerant circulation rate can be reduced, so that the temperature of the refrigerant can be further increased, thereby enhancing the anti-condensation effect.

[0039] Further, before calculating the rate of change of the difference between the first temperature difference and the second temperature difference, it is first determined whether the second temperature difference is greater than or equal to a preset temperature difference, so as to determine whether there is a risk of condensation on the surface of the heat exchange tube. When the second temperature difference is greater than the preset temperature difference, the rate of change of the difference is calculated and compared with a preset rate-of-change threshold value, so as to determine whether it is necessary to adjust the operating speed of the compressor, so as to prevent condensation from occurring on the surface of the heat exchange tube, thereby improving the safety and reliability of the air-conditioning system.

[0040] Further, before, at the same time as, or after reducing the operating opening of the valve body, increasing the operating speed of the fan can reduce the internal temperature of the frequency converter, narrow the difference between the internal temperature of the frequency converter and the refrigerant temperature, and improve the anti-condensation effect.

[0041] Further, when the first temperature difference is less than the preset temperature difference, by increasing the operating opening of the valve body, the flow rate and pressure of the refrigerant can be increased, and the cooling effect of the frequency converter can be improved. In addition, further, when the first temperature difference is less than the preset temperature difference, by reducing the operating opening of the valve body, the flow rate of the refrigerant can be reduced, and condensation on the surface of the heat exchange tube can be avoided.

[0042] Further, when the rate of change of the difference is greater than or equal to the preset rate-of-change threshold value, increasing the operating speed of the compressor can improve the cooling effect of the frequency converter and optimize the energy efficiency of the air-conditioning system. In addition, by controlling the fan on the frequency converter to stop working before, after, or at the same time as increasing the operating speed of the compressor, unnecessary energy consumption can be reduced while ensuring the cooling effect of the frequency converter, and the energy-saving effect of the air-conditioning system can be improved.

[0043] Further, before calculating the rate of change of the difference between the first temperature difference and the second temperature difference, it is first determined whether the second temperature difference is less than the preset temperature difference, so as to determine whether the frequency converter needs further cooling. When the second temperature difference is less than the preset temperature difference, the rate of change of the difference is calculated and compared with a preset rate-of-change threshold value, so as to determine whether it is necessary to adjust the operating speed of the compressor, and the cooling effect of the frequency converter can be enhanced.

[0044] Further, when the first temperature difference is less than the preset temperature difference, by reducing the operating opening of the valve body, the flow rate of the refrigerant can be reduced, and condensation on the surface of the heat exchange tube can be avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings, in which:

[0046] Figure 1 is a flowchart of the control method of the air-conditioning system of the present application;

[0047] Figure 2 is a system diagram of the air-conditioning system of the present application;

[0048] Figure 3It is a logic diagram of a possible implementation manner of the control method of the air conditioning system of the present application.

[0049] Description of the reference numerals:

[0050] 1. Frequency converter; 11. Frequency converter body; 111. Components; 112. Fan; 113. Air outlet; 114. Second temperature sensor; 2. Heat exchange tube; 21. Solenoid valve; 22. First temperature sensor 22; 3. Compressor; 4. Controller. Specific implementation manners

[0051] The preferred implementation manners of the present application will be described below with reference to the accompanying drawings. Those skilled in the art should understand that these implementation manners 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.

[0052] It should be noted that in the description of the present application, the terms indicating the direction or positional relationship such as "upper", "lower", "inner", "bottom", "end" are based on the direction or positional relationship shown in the drawings. This is only for the convenience of description and does not indicate or imply that the device or component must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0053] In addition, it should be noted that in the description of the present application, unless otherwise clearly specified and limited, the terms "set", "connected", "communicated" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, a direct connection, or an indirect connection through an intermediate medium, and it can be the communication inside two components. For those skilled in the art, the specific meanings of the above terms in the present application can be understood according to specific situations.

[0054] First, in combination with Figure 2 , the air conditioning system of the present application will be introduced.

[0055] The air conditioning system of the present application includes a frequency converter 1 and a heat exchange tube 2. The heat exchange tube 2 penetrates through the frequency converter 1 and a valve body is provided at the inlet of the frequency converter 1, so that the refrigerant in the heat exchange tube 2 can exchange heat with the internal temperature of the frequency converter, thereby achieving the purpose of cooling down the frequency converter 1.

[0056] Among them, the valve body can be a solenoid valve 21 or an electronic expansion valve.

[0057] Then refer to Figure 2, the frequency converter 1 includes a frequency converter body 11 and a plurality of components 111 arranged inside the frequency converter 1. The frequency converter body 11 is provided with an inlet and an outlet. One end of the heat exchange tube 2 is connected to the compressor 3 in the air-conditioning system, and the other end enters the frequency converter body 11 from the inlet and extends out of the frequency converter body 11 from the outlet, so that the refrigerant in the heat exchange tube 2 can absorb the heat of the frequency converter 1, thereby achieving the purpose of cooling the frequency converter 1 by using the refrigerant of the air conditioner itself. The heat exchange tube 2 located inside the frequency converter 1 is close to the component 111 to improve the cooling effect of the frequency converter 1. A valve body for controlling the refrigerant flow rate is installed at a position of the heat exchange tube 2 close to the inlet, and the valve body is an electromagnetic valve 21. The electromagnetic valve 21 is located outside the frequency converter 1, and the refrigerant flow rate in the heat exchange tube 2 is controlled by controlling the opening degree of the valve body, thereby cooling the frequency converter 1.

[0058] It should be noted that the valve body can also be arranged on the heat exchange tube 2 near the inlet inside the frequency converter body 11.

[0059] Then refer to Figure 2 , a first temperature sensor 22 is installed at a position of the heat exchange tube 2 close to the inlet. The first temperature sensor 22 is arranged outside the frequency converter body 11, between the electromagnetic valve 21 and the frequency converter 1, and is used to detect the refrigerant temperature at the inlet of the frequency converter 1. A second temperature sensor 114 is installed inside the frequency converter body 11 and is used to detect the internal temperature of the frequency converter. An air outlet 113 is also arranged on the frequency converter body 11. The frequency converter 1 further includes a fan 112. The fan 112 is installed on the frequency converter body 11 and is used to blow air to the components 111 inside the frequency converter 1 and blow out from the air outlet 113, thereby achieving the purpose of auxiliary heat dissipation for the frequency converter 1.

[0060] It should be noted that the first temperature sensor 22 can also be arranged inside the frequency converter body 11 and close to the inlet to obtain the first refrigerant temperature at the inlet of the frequency converter 1.

[0061] Then refer to Figure 2 , the air-conditioning system further includes a controller 4. The controller 4 is respectively connected to the compressor 3, the electromagnetic valve 21, the first temperature sensor 22, the second temperature sensor 114, and the fan 112, so that it is beneficial for the air-conditioning system to intelligently adjust the opening degree of the electromagnetic valve 21, the fan speed, and the operating speed of the compressor 3 according to the refrigerant temperature and the internal temperature of the frequency converter obtained by the first temperature sensor 22 and the second temperature sensor 114.

[0062] Based on the above setting method, the control method of the air-conditioning system of the present application is described.

[0063] As Figure 1 shown, the control method of the air-conditioning system of the present application includes:

[0064] S101. Adjust the operating opening of the valve body according to the first temperature difference between the internal temperature of the first frequency converter and the first refrigerant temperature at the inlet of the frequency converter 1. For example, a first temperature sensor 22 is installed at a position close to the inlet of the heat exchange tube 2 to obtain the first refrigerant temperature. A second temperature sensor 114 is configured inside the frequency converter 1 to obtain the internal temperature of the first frequency converter. After obtaining the internal temperature of the first frequency converter and the first refrigerant temperature, the first temperature difference is obtained by taking the difference between the internal temperature of the first frequency converter and the first refrigerant temperature. By comparing the first temperature difference with a preset temperature difference, the operating opening of the valve body is adjusted.

[0065] S102. After adjusting the operating opening of the valve body, obtain the second refrigerant temperature at the inlet of the frequency converter 1 and the internal temperature of the second frequency converter, and calculate the second temperature difference between the two. For example, after obtaining the first temperature difference, the second refrigerant temperature is obtained through the first temperature sensor 22 and the internal temperature of the second frequency converter is obtained through the second temperature sensor 114, and the second temperature difference is obtained by taking the difference between the internal temperature of the second frequency converter and the second refrigerant temperature.

[0066] S103. Calculate the difference change rate between the first temperature difference and the second temperature difference. For example, after obtaining the first temperature difference and the second temperature difference, according to the difference change rate = |second temperature difference - first temperature difference| × 100% / first temperature difference, the difference change rate is obtained.

[0067] S104. Compare the size of the difference change rate with the preset change rate threshold. For example, after obtaining the difference change rate difference, compare the size of the difference change rate and the preset change rate threshold by comparing whether the difference change rate is greater than 0 or whether the ratio between the two is greater than 1.

[0068] S105. Based on the comparison result, selectively adjust the operating speed of the compressor 3. For example, after determining the size of the difference change rate and the preset change rate threshold, adjust the operating speed of the compressor 3 to avoid the problem of condensation on the surface of the heat exchange tube 2.

[0069] The preferred embodiments of the control method for the air conditioning system of the present application are introduced below.

[0070] In one embodiment, the step of "adjusting the operating opening of the valve body according to the first temperature difference between the internal temperature of the first frequency converter and the first refrigerant temperature at the inlet of the frequency converter 1" further includes:

[0071] When the first temperature difference is greater than or equal to the preset temperature difference, reduce the operating opening of the valve body.

[0072] For example, taking the preset temperature difference ΔT0 as 10 °C, the first temperature difference as ΔT1, and the valve body as the solenoid valve 21 for illustration. After obtaining the internal temperature T1 of the first frequency converter and the first refrigerant temperature T`1, calculate the difference between the two to obtain the first temperature difference ΔT1. When ΔT1 ≥ 10 °C, it indicates that the difference between the internal temperature of the frequency converter and the refrigerant temperature is too large, and condensation is likely to form on the surface of the heat exchange tube 2. Therefore, reduce the operating opening of the solenoid valve 21, so that the refrigerant flow rate in the heat exchange tube 2 decreases and the refrigerant temperature increases, thereby facilitating the reduction of the first temperature difference.

[0073] Further, before, at the same time as, or after the step of "reducing the operating opening of the valve body", it further includes:

[0074] Increase the operating speed of the fan 112 in the frequency converter 1.

[0075] It should be noted that in order to further reduce the difference between the refrigerant temperature and the internal temperature of the frequency converter, the operating speed of the fan 112 can be increased to facilitate the reduction of the internal temperature of the frequency converter.

[0076] In one embodiment, before the step of "calculating the rate of change of the difference between the first temperature difference and the second temperature difference", it further includes:

[0077] Compare the second temperature difference with the preset temperature difference;

[0078] When the second temperature difference is greater than or equal to the preset temperature difference, calculate the rate of change of the difference between the first temperature difference and the second temperature difference.

[0079] It should be noted that before calculating the rate of change of the difference between the first temperature difference and the second temperature difference, it is necessary to first compare the second temperature difference with the preset temperature difference to determine whether there is still a problem of condensation on the heat exchange tube 2.

[0080] For example, taking the preset temperature difference ΔT0 as 10 °C and the second temperature difference as ΔT2 for illustration. After obtaining the internal temperature T2 of the second frequency converter and the second refrigerant temperature T`2, calculate the difference between the internal temperature T2 of the second frequency converter and the second refrigerant temperature T`2 to obtain the second temperature difference ΔT2. When ΔT2 ≥ 10 °C, it indicates that the difference between the internal temperature of the frequency converter and the refrigerant temperature is still relatively large, and condensation is still likely to form on the surface of the heat exchange tube 2. Therefore, when ΔT2 ≥ 10 °C, calculate the rate of change of the difference between the first temperature difference ΔT1 and the second temperature difference ΔT2.

[0081] Furthermore, the control method further includes:

[0082] When the second temperature difference is less than the preset temperature difference, increase the operating opening of the valve body

[0083] For example, taking the preset temperature difference ΔT0 as 10 °C, the second temperature difference as ΔT2, and the valve body as the solenoid valve 21 for illustration. After obtaining the internal temperature T2 of the second frequency converter and the second refrigerant temperature T`2, calculate the difference between the internal temperature T2 of the second frequency converter and the second refrigerant temperature T`2 to obtain the second temperature difference ΔT2. When ΔT2 < 10 °C, it indicates that after the operating opening of the solenoid valve 21 is reduced, the difference between the internal temperature of the frequency converter and the refrigerant temperature becomes smaller, and there is no problem of condensation on the surface of the heat exchange tube 2. At this time, in order to increase the refrigeration effect of the air-conditioning system, the operating opening of the solenoid valve 21 can be increased.

[0084] In one embodiment, the step of "selectively adjusting the operating speed of the compressor 3 based on the comparison result" further includes:

[0085] When the difference change rate is greater than or equal to the preset change rate threshold, or the difference increase rate is greater than or equal to the preset increase rate threshold, reduce the operating speed of the compressor 3.

[0086] It should be noted that after adjusting the operating opening of the valve body, since the flow rate of the refrigerant will change, the temperature of the refrigerant and the internal temperature of the frequency converter 1 inside the frequency converter will also change accordingly. Therefore, it is necessary to continue to obtain the second refrigerant temperature and the second internal temperature of the frequency converter. After calculating the second temperature difference, calculate the difference change rate between the first temperature difference and the second temperature difference. By comparing the difference change rate with the preset change rate threshold, it is possible to illustrate the change situation of the refrigerant temperature and the internal temperature of the frequency converter, and accordingly adjust the operating speed of the compressor 3, which can not only improve the refrigeration effect of the air-conditioning system, but also improve the energy efficiency of the air-conditioning system.

[0087] For example, taking the preset change rate threshold Δδ as 30%, the difference change rate as δ, the first temperature difference as ΔT1, and the second temperature difference as ΔT2 for illustration. After obtaining the first temperature difference ΔT1 and the second temperature difference ΔT2, calculate the difference change rate δ. When δ ≥ 30%, it indicates that the change situation of the temperature difference between the internal temperature of the frequency converter and the refrigerant temperature is relatively obvious. At this time, if the compressor 3 is still maintained at the original operating speed, it will not only reduce the refrigeration effect of the air-conditioning system, but also increase the energy consumption of the air-conditioning system, and may even cause the compressor 3 to malfunction or be damaged frequently in severe cases. Therefore, when δ ≥ 30%, reducing the operating speed of the compressor 3 can not only solve the above problems caused by maintaining the original operating speed of the compressor 3, but also reduce the circulation speed of the refrigerant, thereby further increasing the refrigerant temperature in the heat exchange tube 2 to facilitate solving the problem of condensation on the surface of the heat exchange tube 2. When δ < 30%, it indicates that the change of the temperature difference between the internal temperature of the frequency converter and the refrigerant temperature is relatively not obvious. In this case, adjusting the operating speed of the compressor 3 may affect the air-conditioning refrigeration effect, so there is no need to adjust the operating speed of the compressor 3.

[0088] In one embodiment, the control method further includes:

[0089] When the first temperature difference is less than the preset temperature difference, increase the operating opening of the valve body.

[0090] It should be noted that when the first temperature difference is much less than the preset temperature difference, it indicates that the heat exchange tube 2 cannot achieve a good cooling effect on the frequency converter 1. Therefore, it is necessary to increase the operating opening of the valve body to increase the flow rate of the refrigerant in the heat exchange tube 2, thereby enhancing the cooling effect on the frequency converter 1.

[0091] For example, taking the preset temperature difference ΔT0 as 10 °C, the first temperature difference as ΔT1, and the valve body as the solenoid valve 21 for illustration. After obtaining the internal temperature T1 of the first frequency converter and the first refrigerant temperature T`2, calculate the difference between the two to obtain the first temperature difference ΔT1. When ΔT1 < 10 °C, it indicates that the difference between the internal temperature of the frequency converter and the refrigerant temperature is small. Although condensation will not form on the surface of the heat exchange tube 2, the heat exchange tube 2 cannot achieve a good cooling effect on the frequency converter 1. Therefore, increase the operating opening of the solenoid valve 21 to increase the refrigerant flow rate in the heat exchange tube 2 to improve the cooling effect of the frequency converter 1.

[0092] Furthermore, before, at the same time as, or after the step of "increasing the operating opening of the valve body", it also includes:

[0093] Reduce the operating speed of the fan 112 in the frequency converter 1.

[0094] It should be noted that in order to avoid excessive cooling effect of the frequency converter 1 and reduce energy consumption, before, after, or at the same time as increasing the operating opening of the valve body, the operating speed of the fan 112 can also be reduced.

[0095] Furthermore, before the step of "calculating the rate of change of the difference between the first temperature difference and the second temperature difference", it also includes:

[0096] Compare the size of the second temperature difference and the preset temperature difference;

[0097] When the second temperature difference is less than the preset temperature difference, calculate the rate of change of the difference between the first temperature difference and the second temperature difference.

[0098] It should be noted that before calculating the rate of change of the difference between the first temperature difference and the second temperature difference, it is necessary to first compare the size of the second temperature difference and the preset temperature difference to determine whether the frequency converter 1 still needs to be cooled down.

[0099] For example, taking the preset temperature difference ΔT0 as 10°C, the second temperature difference as ΔT2, and the valve body as the solenoid valve 21 for illustration. After obtaining the internal temperature T2 of the second frequency converter and the second refrigerant temperature T`2, calculate the difference between the internal temperature T2 of the second frequency converter and the second refrigerant temperature T`2 to obtain the second temperature difference ΔT2. When ΔT2 < 10°C, it indicates that after the operating opening of the solenoid valve 21 increases, the difference between the internal temperature of the frequency converter and the refrigerant temperature is still relatively small, and the frequency converter 1 still needs to be cooled down. At this time, the rate of change of the difference between the first temperature difference ΔT1 and the second temperature difference ΔT2 can be calculated.

[0100] Further, the control method further includes:

[0101] When the second temperature difference is greater than or equal to the preset temperature difference, reduce the operating opening of the valve body.

[0102] For example, taking the preset temperature difference ΔT0 as 10°C, the second temperature difference as ΔT2, and the valve body as the solenoid valve 21 for illustration. After obtaining the internal temperature T2 of the second frequency converter and the second refrigerant temperature T`2, calculate the difference between the internal temperature T2 of the second frequency converter and the second refrigerant temperature T`2 to obtain the second temperature difference ΔT2. When ΔT2 ≥ 10°C, it indicates that after the operating opening of the solenoid valve 21 increases, the difference between the internal temperature of the frequency converter and the refrigerant temperature becomes larger, and there is a problem of condensation on the surface of the heat exchange tube 2. At this time, in order to avoid condensation on the surface of the heat exchange tube 2, the operating opening of the solenoid valve 21 can be reduced.

[0103] The step of "selectively adjusting the operating speed of the compressor 3 based on the comparison result" further includes:

[0104] When the rate of change of the difference is greater than or equal to the preset rate-of-change threshold, increase the operating speed of the compressor 3.

[0105] For example, taking the preset rate-of-change threshold Δδ as 30%, the rate of change of the difference as δ, the first temperature difference as ΔT1, and the second temperature difference as ΔT2 for illustration. After obtaining the rate of change of the difference δ, compare the size of the rate of change of the difference δ greater than or equal to the preset rate-of-change threshold Δδ. When δ ≥ 30%, it indicates that the change in the temperature difference between the internal temperature of the frequency converter and the refrigerant temperature is relatively obvious, and the cooling effect of the heat exchange tube 2 is obvious. At this time, if the compressor 3 is still maintained at the original operating speed, not only will the refrigeration effect of the air-conditioning system and the pressure of the compressor 3 increase, but also the energy consumption of the air-conditioning system will increase. Therefore, when δ ≥ 30%, increasing the operating speed of the compressor 3 can not only solve the above problems caused by maintaining the operating speed of the compressor 3, but also improve the circulation speed of the refrigerant, thereby improving the cooling effect of the frequency converter 1. When δ < 30%, it indicates that the change in the temperature difference between the internal temperature of the frequency converter and the refrigerant temperature is relatively not obvious. In this case, adjusting the operating speed of the compressor 3 may affect the air-conditioning refrigeration effect, so there is no need to adjust the operating speed of the compressor 3.

[0106] Further, after the step of "increasing the operating speed of the compressor 3", it includes:

[0107] Controlling the fan 112 in the frequency converter 1 to stop working.

[0108] It should be noted that by increasing the operating opening degree of the valve body and the operating speed of the compressor 3, the frequency converter 1 can already obtain a good heat dissipation effect. At this time, the continuous operation of the fan 112 not only has an insignificant cooling effect, but also increases unnecessary energy consumption. Therefore, in this case, controlling the fan 112 to stop running can achieve a better energy-saving effect.

[0109] Next, in combination with Figure 3 a possible operating process of the control method of the air-conditioning system of the present application will be briefly described. Figure 3 It is a logic diagram of a possible implementation manner of the control method of the air-conditioning system of the present application.

[0110] S201. Obtain the internal temperature T1 of the first frequency converter and the first refrigerant temperature T`1 at the inlet of the frequency converter 1, and then execute S202.

[0111] S202. Calculate the first temperature difference ΔT1 between the internal temperature T1 of the first frequency converter and the first refrigerant temperature T`1, and then execute S203.

[0112] S203. Determine whether ΔT1≥10°C? If yes, execute S203; otherwise execute S211.

[0113] S204. Reduce the operating opening degree of the solenoid valve 21 and increase the operating speed of the fan 112 at the same time.

[0114] S205. Then obtain the internal temperature T2 of the second frequency converter and the second refrigerant temperature T`2 at the inlet of the frequency converter 1, and then execute S206.

[0115] S206. Calculate the second temperature difference ΔT2 between the internal temperature T2 of the second frequency converter and the second refrigerant temperature T`2, and then execute S207.

[0116] S207. Determine whether ΔT2≥10°C? If yes, execute S208; otherwise execute S211.

[0117] S208. Calculate the difference change rate δ between the first temperature difference ΔT1 and the second temperature difference ΔT2, and then execute S209.

[0118] S209. Determine whether δ≥30%? If yes, execute S210; otherwise execute S205.

[0119] S210. Reduce the operating speed of the compressor 3, and then execute S201.

[0120] S211. Increase the operating opening of the solenoid valve 21, and then execute S212.

[0121] S212. Then obtain the internal temperature T2 of the second frequency converter and the second refrigerant temperature T`2 at the inlet of the frequency converter 1, and then execute S213.

[0122] S213. Calculate the second temperature difference ΔT2 between the internal temperature T2 of the second frequency converter and the second refrigerant temperature T`2, and then execute S214.

[0123] S214. Determine whether ΔT2 < 10°C? If yes, execute S215; otherwise, execute S204.

[0124] S215. Calculate the difference change rate δ between the first temperature difference ΔT1 and the second temperature difference ΔT2, and then execute S216.

[0125] S216. Determine whether δ ≥ 30%? If yes, execute S217; otherwise, execute S212.

[0126] S217. While reducing the operating speed of the compressor 3, control the fan 112 to stop working, and then execute S201.

[0127] 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.

[0128] So far, the technical solutions of this application have been described in conjunction with the preferred embodiments shown in the accompanying 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 all fall within the protection scope of this application.

Claims

1. A control method for an air conditioning system, characterized in that, The air conditioning system includes an inverter and a heat exchange tube. The heat exchange tube passes through the inverter, and a valve body is provided at the inlet of the inverter. The control method includes: Adjust the operating opening of the valve body according to a first temperature difference between the internal temperature of the first inverter and the first refrigerant temperature at the inlet of the inverter; After adjusting the operating opening of the valve body, obtain the second refrigerant temperature and the second internal temperature of the inverter at the inlet of the inverter, and calculate a second temperature difference between the two; Calculate a difference change rate between the first temperature difference and the second temperature difference; Compare the size of the difference change rate with a preset change rate threshold; Based on the comparison result, selectively adjust the operating speed of the compressor.

2. The control method according to claim 1, wherein The step of "adjusting the operating opening of the valve body according to a first temperature difference between the internal temperature of the first inverter and the first refrigerant temperature at the inlet of the inverter" further includes: When the first temperature difference is greater than or equal to a preset temperature difference, reduce the operating opening of the valve body.

3. The control method according to claim 2, wherein The step of "selectively adjusting the operating speed of the compressor based on the comparison result" further includes: When the difference change rate is greater than or equal to the preset change rate threshold, reduce the operating speed of the compressor.

4. The control method according to claim 2 or 3, characterized in that Before the step of "calculating a difference change rate between the first temperature difference and the second temperature difference", it further includes: Compare the size of the second temperature difference with the preset temperature difference; When the second temperature difference is greater than or equal to the preset temperature difference, calculate a difference change rate between the first temperature difference and the second temperature difference.

5. The control method according to claim 4, characterized in that The control method further includes: When the second temperature difference is less than the preset temperature difference, increase the operating opening of the valve body.

6. The control method according to claim 2, wherein Before, at the same time as, or after the step of "reducing the operating opening of the valve body", it further includes: Increase the operating speed of the fan in the inverter.

7. The control method according to claim 2, characterized in that The control method further includes: When the first temperature difference is less than the preset temperature difference, increase the operating opening of the valve body; Preferably, before, at the same time as, or after the step of "increasing the operating opening of the valve body", it further includes: Reduce the operating speed of the fan.

8. The control method according to claim 7, wherein The step of "selectively adjusting the operating speed of the compressor based on the comparison result" further includes: When the difference change rate is greater than or equal to the preset change rate threshold, increase the operating speed of the compressor; Preferably, before, at the same time as, or after the step of "increasing the operating speed of the compressor", it further includes: Control the fan to stop working.

9. The control method according to any one of claims 7-8, characterized in that, Before the step of "calculating a difference change rate between the first temperature difference and the second temperature difference", it further includes: Compare the size of the second temperature difference with the preset temperature difference; When the second temperature difference is less than the preset temperature difference, calculate a difference change rate between the first temperature difference and the second temperature difference.

10. The control method according to claim 9, characterized in that, The control method further includes: When the second temperature difference is greater than or equal to the preset temperature difference, reduce the operating opening of the valve body.

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