Control method of air conditioning system

Abstract

This invention relates to the field of air conditioning systems, specifically providing a control method for an air conditioning system, aiming to solve the problem that existing air conditioning systems struggle to simultaneously achieve both high energy efficiency ratio and high heating performance. To this end, the control method of this application utilizes the difference between the intermediate temperature and the return air temperature as the basis for adjusting the opening of the electronic expansion valve when the air conditioning system meets the triggering conditions of the second operating mode. This accurately reflects the actual heat exchange efficiency of the refrigerant circulation, optimizes the dynamic matching relationship between the refrigerant circulation flow and the indoor heat load, and enables the air conditioning system to maintain stable heating output without changing the compressor operating frequency during heating. Simultaneously, it effectively reduces ineffective energy consumption caused by unreasonable refrigerant flow, thereby enabling the air conditioning system to simultaneously achieve excellent heating performance and a high energy efficiency ratio.

Description

Technical Field

[0001] This invention relates to the field of air conditioning system technology, and more specifically to a control method for an air conditioning system. Background Technology

[0002] With increasingly stringent energy conservation and environmental protection requirements, variable frequency air conditioning systems have been widely adopted. However, in the operation of existing air conditioning systems, it is often difficult to effectively balance energy efficiency ratio and heating effect: if the compressor operating frequency is reduced to pursue a higher energy efficiency ratio, the heating capacity will be significantly reduced; conversely, if the compressor operating frequency is increased to enhance the heating effect, the energy efficiency ratio will decrease significantly.

[0003] Accordingly, a new technical solution is needed in this field to solve the above problems. Summary of the Invention

[0004] This invention aims to solve the aforementioned technical problem, namely, the difficulty in simultaneously achieving high energy efficiency ratio and effective heating in existing air conditioning systems. Based on this, this application provides a control method for an air conditioning system, comprising: responding to a received heating command, controlling the air conditioning system to operate in a first operating mode; wherein the first operating mode is a normal operating mode; acquiring a first operating frequency f1 of the compressor in the air conditioning system; determining, based on the first operating frequency f1, whether the air conditioning system meets the triggering conditions for entering a second operating mode; when the triggering conditions are met, acquiring a first intermediate temperature K1 of the condenser and a first return gas temperature C1 of the compressor in the air conditioning system; calculating a first temperature difference ΔT1 between the first intermediate temperature K1 and the first return gas temperature C1; and controlling the opening degree of the electronic expansion valve in the air conditioning system according to the temperature difference range in which the first temperature difference ΔT1 is located.

[0005] In the preferred embodiment of the above control method, the step of "controlling the opening degree adjustment of the electronic expansion valve in the air conditioning system according to the temperature range where the first temperature difference ΔT1 is located" further includes: when ΔT1≥ΔT 1 When ΔT decreases, the opening of the electronic expansion valve is reduced while maintaining the operating frequency of the compressor unchanged; if ΔT 1 >ΔT1≥ΔT 2 At the same time, maintain the current target discharge temperature and operating frequency of the compressor unchanged; if ΔT1 < ΔT 2 At the same time, the opening degree of the electronic expansion valve is increased while the operating frequency of the compressor remains constant; wherein, ΔT 1 The first temperature difference threshold, ΔT 2 This is the second temperature difference threshold.

[0006] In the preferred embodiment of the above control method, after the step of "controlling the opening adjustment of the electronic expansion valve in the air conditioning system", the method further includes: after a first set time, acquiring the second intermediate temperature K2 and the second return air temperature C2; ​​calculating the second temperature difference ΔT2 between the second intermediate temperature K2 and the second return air temperature C2; ​​and comparing the second temperature difference ΔT2 with the first temperature difference threshold ΔT. 1 Second temperature difference threshold ΔT 2 The magnitude; when ΔT2 ≥ ΔT 1 If ΔT decreases, the opening of the electronic expansion valve is reduced while maintaining the operating frequency of the compressor unchanged; 1 >ΔT2≥ΔT 2 If the current target exhaust temperature and operating frequency of the compressor remain unchanged, then the compressor's current target exhaust temperature and operating frequency will remain unchanged; if ΔT2 < ΔT 2 If the opening of the electronic expansion valve is increased, the operating frequency of the compressor will remain unchanged; the above steps will be repeated until the air conditioning system exits the second operating mode.

[0007] In the preferred embodiment of the above control method, the step of "reducing the opening of the electronic expansion valve" specifically includes: obtaining a first target exhaust temperature; calculating the sum of the first target exhaust temperature and a preset temperature increment to obtain a second target exhaust temperature; and reducing the opening of the electronic expansion valve based on the second target exhaust temperature.

[0008] In a preferred embodiment of the above control method, before the step of "reducing the opening of the electronic expansion valve based on the second target exhaust temperature", the method further includes: comparing the second target exhaust temperature with a preset exhaust temperature; when the second target exhaust temperature is less than the preset exhaust temperature, reducing the opening of the electronic expansion valve based on the second target exhaust temperature; when the second target exhaust temperature is greater than or equal to the preset exhaust temperature, reducing the opening of the electronic expansion valve based on the preset exhaust temperature.

[0009] In the preferred embodiment of the above control method, the step of "increasing the opening of the electronic expansion valve" specifically includes: obtaining a first target exhaust temperature; calculating the difference between the first target exhaust temperature and the preset temperature reduction to obtain a third target exhaust temperature; and increasing the opening of the electronic expansion valve based on the third target exhaust temperature.

[0010] In a preferred embodiment of the above control method, after the step of controlling the opening adjustment of the electronic expansion valve, the method further includes: acquiring multiple first coil temperatures within the current adjustment cycle and multiple second coil temperatures within the previous adjustment cycle; calculating a first average value of the multiple first coil temperatures and a second average value of the multiple second coil temperatures; calculating the difference between the first average value and the second average value; comparing the difference with a preset difference; if the difference is less than the preset difference, counting is performed and the cumulative number of times is counted; if the cumulative number of times within a preset time period is greater than or equal to the preset number of times, the operation of reducing the opening of the electronic expansion valve is stopped; wherein, the preset difference is less than or equal to zero.

[0011] In the preferred embodiment of the above control method, after or simultaneously with the step of "stopping the operation of reducing the opening of the electronic expansion valve", the method further includes: increasing the opening of the electronic expansion valve, or maintaining the target exhaust temperature unchanged.

[0012] In the preferred embodiment of the above control method, the triggering condition is that the compressor runs continuously at a first operating frequency f1 for a preset duration.

[0013] In a preferred embodiment of the above control method, after the air conditioning system enters the second operating mode, the control method further includes: obtaining the second operating frequency f2 of the compressor; determining whether the second operating frequency f2 is equal to the first operating frequency f1; and controlling the air conditioning system to switch to the first operating mode when the second operating frequency f2 is not equal to the first operating frequency f1.

[0014] Those skilled in the art will understand that the air conditioning system control method of this application, when the air conditioning system meets the triggering conditions of the second operating mode, uses the difference between the intermediate temperature and the return air temperature as the basis for adjusting the opening of the electronic expansion valve, thereby accurately reflecting the actual heat exchange efficiency of the refrigerant circulation, optimizing the dynamic matching relationship between the refrigerant circulation flow and the indoor heat load, so that the air conditioning system can maintain a stable heating output capacity without changing the compressor operating frequency during the heating process, while effectively reducing the ineffective energy consumption caused by unreasonable refrigerant flow, thus enabling the air conditioning system to simultaneously achieve excellent heating effect and high energy efficiency ratio.

[0015] Furthermore, by dividing the temperature difference into three intervals and adopting differentiated electronic expansion valve adjustment strategies for each temperature interval, the air conditioning system can further improve its energy efficiency ratio while ensuring stable heating output capacity.

[0016] Furthermore, by superimposing the first target exhaust temperature with the preset temperature increment to obtain a higher second target exhaust temperature, and using this to adjust the opening of the electronic expansion valve, the energy efficiency ratio can be improved while ensuring that the heating capacity does not decrease, so that the air conditioning system can effectively balance excellent heating effect and high energy efficiency ratio.

[0017] Furthermore, by setting the preset exhaust temperature as the upper limit of the second target exhaust temperature, it is possible to prevent abnormal increases in exhaust temperature, thereby avoiding the risk of decreased system energy efficiency and equipment damage.

[0018] Furthermore, by subtracting the first target exhaust temperature from the preset temperature to obtain a lower third target exhaust temperature, the opening of the electronic expansion valve is increased. This ensures stable system operation and improves the refrigerant circulation state by lowering the target exhaust temperature, thereby reducing the operating energy consumption of the air conditioning system.

[0019] Furthermore, by cyclically sampling and comparing the temperature difference every first set time after the initial adjustment of the electronic expansion valve opening, the opening of the electronic expansion valve is adjusted accordingly, thereby ensuring that the air conditioning system always achieves the best balance between heating effect and energy efficiency ratio.

[0020] Furthermore, by calculating the difference between the current average coil temperature and the average temperature of the previous adjustment cycle, and counting and accumulating the number of times when the difference is less than the preset difference, the operation of reducing the opening of the electronic expansion valve is stopped when the cumulative number of times reaches the preset number within the preset time period. On the one hand, this can avoid the risk of reduced heating capacity due to excessive valve closure, and on the other hand, it can prevent problems such as evaporator frosting caused by insufficient refrigerant flow, thereby improving the heating stability and operational reliability of the air conditioning system.

[0021] Furthermore, after or simultaneously with ceasing the operation of reducing the opening of the electronic expansion valve, increasing the opening of the electronic expansion valve or maintaining the target exhaust temperature can resolve the trend of decreasing coil temperature, restore refrigerant flow and heat exchange efficiency, and prevent the frosting from worsening due to throttling.

[0022] Furthermore, in the second operating mode, when a change in the compressor's operating frequency is detected, the air conditioning system automatically switches to the first operating mode, thereby avoiding adjustment disorder or system abnormality caused by frequency changes, and thus improving the operational reliability of the air conditioning system. Attached Figure Description

[0023] The preferred embodiments of the present invention are described below with reference to the accompanying drawings, in which: Figure 1 This is a logic diagram of one possible implementation of the control method for the air conditioning system of this application. Detailed Implementation

[0024] Preferred embodiments of this application will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of this application and are not intended to limit the scope of protection of this application.

[0025] The control method for the air conditioning system in this application includes:

[0026] S101. In response to the received heating command, control the air conditioning system to operate in a first operating mode; wherein, the first operating mode is a normal operating mode. For example, after receiving a heating command from the user via remote control or mobile terminal, the air conditioning system immediately starts and enters the first operating mode. In this mode, the compressor performs frequency conversion adjustment according to operating conditions such as indoor ambient temperature and set temperature: initially, the compressor operates at the maximum frequency allowed by the current operating conditions to achieve rapid heating; when the indoor temperature approaches the set temperature, the compressor's operating frequency decreases accordingly; if the indoor ambient temperature subsequently decreases, the frequency increases accordingly.

[0027] S102. Obtain the first operating frequency f1 of the compressor in the air conditioning system. For example, the air conditioning system is equipped with a frequency detection module and multiple temperature detection modules. The operating frequency of the compressor can be obtained through the frequency detection module.

[0028] S103. Based on the first operating frequency f1, determine whether the air conditioning system meets the trigger condition for entering the second operating mode. For example, the trigger condition could be that the compressor runs continuously at the first operating frequency f1 for a preset duration. When the system detects that the compressor has run continuously at the first operating frequency f1 for the preset duration, it determines that the trigger condition for entering the second operating mode is met. The determination logic for this trigger condition can be pre-stored in the controller of the air conditioning system.

[0029] S104. When the triggering condition is met, acquire the first intermediate temperature K1 of the condenser and the first return gas temperature C1 of the compressor in the air conditioning system. For example, an air conditioning system is typically equipped with multiple temperature sensors, which are used to detect the intermediate temperature of the condenser and the return gas temperature of the compressor, respectively. The intermediate temperature refers to the temperature of the two-phase region in the condenser.

[0030] S105. Calculate the first temperature difference ΔT1 between the first intermediate temperature K1 and the first return gas temperature C1. For example, after obtaining the first intermediate temperature and the first return gas temperature, calculate the difference between the first intermediate temperature and the first return gas temperature, and record this difference as the first temperature difference. This difference can be used to reflect the heat exchange efficiency or subcooling state of the condenser.

[0031] S106. Based on the temperature difference range where the first temperature difference value ΔT1 falls, control the opening degree of the electronic expansion valve in the air conditioning system. For example, one or more temperature difference thresholds can be preset in the air conditioning system to divide different temperature difference ranges, such as a first temperature difference range, a second temperature difference range, etc. Each temperature difference range corresponds to an opening degree control strategy for the electronic expansion valve, such as maintaining the opening degree, increasing the opening degree, or decreasing the opening degree. When the calculated first temperature difference value falls into a certain temperature difference range, adjust the opening degree of the electronic expansion valve according to the control strategy corresponding to that range.

[0032] This application utilizes the difference between the intermediate temperature and the return air temperature as the basis for adjusting the opening of the electronic expansion valve when the air conditioning system meets the triggering conditions of the second operating mode. This accurately reflects the actual heat exchange efficiency of the refrigerant circulation, optimizes the dynamic matching relationship between the refrigerant circulation flow and the indoor heat load, and enables the air conditioning system to maintain a stable heating output capacity without changing the compressor operating frequency during the heating process. At the same time, it effectively reduces the ineffective energy consumption caused by unreasonable refrigerant flow, thereby enabling the air conditioning system to simultaneously achieve excellent heating effect and high energy efficiency ratio.

[0033] The preferred embodiments of the air conditioning system control method of this application are described below.

[0034] In one embodiment, the triggering condition is that the compressor runs continuously at a first operating frequency f1 for a preset duration.

[0035] It should be noted that, in response to the heating command, the air conditioning system enters normal operation mode. In normal operation mode, the air conditioning system alternates between two stages: In the first stage, based on the indoor ambient temperature, the set temperature, and other operating conditions, it operates at the maximum allowed operating frequency (i.e., the first operating frequency) to rapidly bring the indoor ambient temperature close to the set temperature; in the second stage, when the indoor ambient temperature approaches the set temperature, the compressor's operating frequency is dynamically adjusted. The second operating mode requires the compressor's operating frequency to remain fixed, therefore it can only occur in the first stage. In the second stage, the indoor ambient temperature is already close to the set temperature, and the compressor is in a low-frequency, continuously dynamically adjusting state, which does not meet the conditions for the second operating mode, therefore the second operating mode does not occur in this stage. In this application, the first operating frequency generally refers to the compressor's operating frequency obtained in each of the first stages.

[0036] For example, let's define the duration (t) for which the compressor runs continuously at the first operating frequency (f1), with a preset duration (t0) of 6 minutes. The air conditioning system can accumulate the duration (t) for continuous operation at the first operating frequency (f1). When t ≥ 6 minutes, it is determined that the trigger condition for entering the second operating mode is met. When t < 6 minutes, it indicates that the air conditioning system does not meet the trigger condition for the second operating mode, and it needs to continue acquiring the first operating frequency and accumulating the duration for which the compressor runs continuously at the first operating frequency.

[0037] In one embodiment, the step of "controlling the opening degree of the electronic expansion valve in the air conditioning system according to the temperature range in which the first temperature difference ΔT1 is located" further includes: When ΔT1≥ΔT 1 At the same time, reduce the opening of the electronic expansion valve while maintaining the compressor's operating frequency unchanged; If ΔT 1 >ΔT1≥ΔT 2 At the same time, the compressor's current target discharge temperature and operating frequency remain unchanged; If ΔT1 < ΔT 2 At the same time, increase the opening of the electronic expansion valve while maintaining the compressor's operating frequency unchanged; Where, ΔT 1 The first temperature difference threshold, ΔT 2 This is the second temperature difference threshold.

[0038] It should be noted that "maintaining the target exhaust temperature unchanged" means stabilizing the exhaust temperature at the target value by adjusting the opening of the electronic expansion valve, rather than keeping the opening of the electronic expansion valve unchanged; "maintaining the compressor operating frequency unchanged" means keeping the compressor running at the first operating frequency.

[0039] For example, using the first temperature difference threshold ΔT 1 The second temperature difference threshold ΔT is 1℃. 2 The explanation is based on 0℃. When the air conditioning system meets the trigger conditions for entering the second operating mode, the first intermediate temperature K1 of the condenser and the first return gas temperature C1 of the compressor in the air conditioning system are obtained. The first temperature difference ΔT1 between the first intermediate temperature K1 and the first return gas temperature C1 is calculated. When ΔT1 ≥ 1℃, it indicates insufficient subcooling, and the condenser has not been able to exchange heat sufficiently, resulting in high condensing pressure. Therefore, it is necessary to reduce the opening of the electronic expansion valve, increase the throttling resistance, and reduce the refrigerant circulation flow rate to prolong the residence time of the refrigerant in the condenser, thereby enabling sufficient heat dissipation and establishing a reasonable subcooling. At the same time, maintaining the first operating frequency f1 of the compressor unchanged can effectively reduce the condensing pressure and compression ratio without affecting the heating capacity, restoring the air conditioning system from an unbalanced state of high energy consumption and low energy efficiency to a balanced state between heating output and energy consumption.

[0040] When 1℃ > ΔT1 ≥ 0℃, it indicates that the subcooling and return superheat of the air conditioning system are both within a suitable range, and the refrigerant flow rate and condenser heat exchange capacity are well matched. At this time, the heating and energy consumption of the air conditioning system have reached a relatively optimal balance, and there is no need to actively intervene in the compressor operating frequency or the target value of the exhaust temperature. Therefore, by maintaining the target exhaust temperature of the compressor and the first operating frequency f1 of the compressor unchanged, the electronic expansion valve is allowed to automatically adjust around the target exhaust temperature to stabilize the exhaust temperature, so that the air conditioning system continues to operate at this optimal operating point.

[0041] When ΔT1 < 0℃, it indicates excessive subcooling, causing a large accumulation of liquid refrigerant in the downstream section of the condenser. This leads to excessive liquid supply to the evaporator, higher evaporation pressure, and decreased heating efficiency. Therefore, it is necessary to increase the opening of the electronic expansion valve, reduce throttling resistance, and increase the refrigerant circulation flow rate. This allows the refrigerant in the condenser to flow more rapidly to the evaporator, reducing subcooling. Simultaneously, maintaining the compressor's initial operating frequency f1 unchanged can effectively reduce condensing and evaporating pressures without affecting heating capacity. This restores the air conditioning system from a state of high energy consumption and low efficiency to a balanced state between heating output and energy consumption.

[0042] Furthermore, after the step of "controlling the opening adjustment of the electronic expansion valve in the air conditioning system", the following is also included: After a first set time, the second intermediate temperature K2 and the second return gas temperature C2 are obtained; Calculate the second temperature difference ΔT2 between the second intermediate temperature K2 and the second return gas temperature C2; Compare the second temperature difference ΔT2 and the first temperature difference threshold ΔT respectively. 1 Second temperature difference threshold ΔT 2 Size; When ΔT2≥ΔT 1 This reduces the opening of the electronic expansion valve while maintaining the compressor's operating frequency unchanged; If ΔT 1 >ΔT2≥ΔT 2 Then the compressor's current target discharge temperature and operating frequency will remain unchanged; If ΔT2 < ΔT 2 This increases the opening of the electronic expansion valve while maintaining the compressor's operating frequency unchanged; Repeat the above steps until the air conditioning system exits the second operating mode.

[0043] It should be noted that the above steps occur after the opening of the electronic expansion valve is adjusted within the temperature difference range where the first temperature difference value is located. After that, every first set time, the intermediate temperature and return gas temperature are collected again, and a new round of temperature difference range judgment and valve step adjustment is performed. This cycle repeats to form a continuous closed-loop control.

[0044] For example, with a first set time of 6 minutes and a first temperature difference threshold ΔT 1 The second temperature difference threshold ΔT is 1℃. 2 The temperature is set to 0℃. After adjusting the opening of the electronic expansion valve based on the temperature difference range where the first temperature difference ΔT1 falls, the second intermediate temperature K2 and the second return gas temperature C2 are obtained after 6 minutes. The second temperature difference ΔT2 is calculated. Subsequently, the second temperature difference ΔT2 is compared with the first temperature difference threshold ΔT. 1 Second temperature difference threshold ΔT 2 When ΔT2 ≥ 1℃, the opening of the electronic expansion valve is reduced while maintaining the compressor's first operating frequency f1 unchanged; when 1℃ > ΔT2 ≥ 0℃, the compressor's current target discharge temperature and first operating frequency f1 remain unchanged; when ΔT2 < 0℃, the opening of the electronic expansion valve is increased while maintaining the compressor's first operating frequency f1 unchanged. This cycle continues until the air conditioning system exits the second operating mode.

[0045] Furthermore, the steps of "reducing the opening of the electronic expansion valve" specifically include: Obtain the first target exhaust temperature; The second target exhaust temperature is obtained by summing the first target exhaust temperature and the preset temperature increment. Based on the second target exhaust temperature, reduce the opening of the electronic expansion valve.

[0046] It should be noted that the first target exhaust temperature varies depending on the operating stage of the air conditioning system in the second operating mode, and falls into two categories: The first category occurs when the air conditioning system has just entered the second operating mode (i.e., at the end of the first operating mode). In this case, the first target exhaust temperature is determined based on the operating status of the air conditioning system. The second category occurs during subsequent adjustments in the second operating mode. Regardless of whether the previous adjustment cycle executed a control action of decreasing the electronic expansion valve opening, increasing the electronic expansion valve opening, or maintaining the target exhaust temperature, after adjusting the electronic expansion valve opening once every first set time interval, the first target exhaust temperature used in the current adjustment cycle will continue from the target exhaust temperature of the previous adjustment cycle.

[0047] The adjustment cycle refers to the time interval from the start of one electronic expansion valve opening adjustment action to the end of the first set time.

[0048] It should also be noted that, based on the second target exhaust temperature, the opening of the electronic expansion valve is reduced. Specifically, this includes: reducing the opening of the electronic expansion valve based on the second target exhaust temperature until the exhaust temperature reaches the second target exhaust temperature; then, using the second target exhaust temperature as the adjustment target, controlling the opening of the electronic expansion valve to maintain the actual exhaust temperature at the second target exhaust temperature.

[0049] For example, using the first temperature difference threshold ΔT 1 Let P1 be the first target exhaust temperature and P2 be the second target exhaust temperature. The preset temperature increment ΔP1 is 1℃. The adjustment process for the air conditioning system upon startup and initial entry into the second operating mode is explained. When ΔT1 ≥ 1℃, the first target exhaust temperature P1 is obtained. The sum of the first target exhaust temperature P1 and the preset temperature increment ΔP1 (1℃) is calculated to obtain the second target exhaust temperature P2. Since the second target exhaust temperature P2 is 1℃ higher than the first target exhaust temperature, the opening of the electronic expansion valve is reduced based on the second target exhaust temperature, so that the actual exhaust temperature reaches the second target exhaust temperature P2. Subsequently, the opening of the electronic expansion valve is dynamically adjusted with the second target exhaust temperature P2 as the adjustment target to maintain the actual exhaust temperature at the second target exhaust temperature P2.

[0050] To illustrate further, let's take the first temperature difference threshold ΔT as an example. 1 The second temperature difference threshold ΔT is 1℃. 2 The initial temperature is 0℃, the first target exhaust temperature is P1, the second target exhaust temperature is P2, and the preset temperature increment ΔP1 is 1℃. The subsequent adjustment process after the air conditioning system enters the second operating mode is explained. When ΔT1 ≥ 1℃, the first target exhaust temperature P1 is obtained, and the sum of the first target exhaust temperature P1 and the preset temperature increment ΔP1 (1℃) is calculated to obtain the second target exhaust temperature P2. Based on the second target exhaust temperature P2, the opening of the electronic expansion valve is reduced. After 6 minutes, ΔT2 ≥ 1℃, then P2 from the previous adjustment cycle is used as the first target exhaust temperature P1 for the current adjustment cycle. The sum of this first target exhaust temperature P1 and the preset temperature increment ΔP1 (1℃) is calculated to obtain the new second target exhaust temperature P2. Based on this second target exhaust temperature P2, the opening of the electronic expansion valve is reduced so that the actual exhaust temperature reaches the second target exhaust temperature P2; subsequently, the opening of the electronic expansion valve is dynamically adjusted with the second target exhaust temperature P2 as the adjustment target to maintain the actual exhaust temperature at the second target exhaust temperature P2.

[0051] To illustrate further, let's take the first temperature difference threshold ΔT as an example. 1 The second temperature difference threshold ΔT is 1℃. 2The initial temperature is 0°C, the first target exhaust temperature is P1, the second target exhaust temperature is P2, and the preset temperature increment ΔP1 is 1°C. The subsequent adjustment process after the air-conditioning system enters the second operating mode will be described. When 1°C > ΔT1 ≥ 0°C, the target exhaust temperature of the air-conditioning system is controlled to remain unchanged. After 6 minutes, when ΔT2 ≥ 1°C, the target exhaust temperature of the previous adjustment cycle is used as the first target exhaust temperature P1 of the current adjustment cycle. Calculate the sum of this first target exhaust temperature P1 and the preset temperature increment ΔP1 (1°C) to obtain the second target exhaust temperature P2. Based on this second target exhaust temperature P2, reduce the opening degree of the electronic expansion valve so that the actual exhaust temperature reaches the second target exhaust temperature P2; subsequently, dynamically adjust the opening degree of the electronic expansion valve with the second target exhaust temperature P2 as the adjustment target to maintain the actual exhaust temperature at the second target exhaust temperature P2.

[0052] Furthermore, before the step of "reducing the opening degree of the electronic expansion valve based on the second target exhaust temperature", the following steps are also included: Compare the second target exhaust temperature with the preset exhaust temperature. When the second target exhaust temperature is less than the preset exhaust temperature, reduce the opening degree of the electronic expansion valve based on the second target exhaust temperature. When the second target exhaust temperature is greater than or equal to the preset exhaust temperature, reduce the opening degree of the electronic expansion valve based on the preset exhaust temperature.

[0053] It should be noted that the preset exhaust temperature is less than or equal to the maximum target exhaust temperature allowed by the air-conditioning system. There is a maximum exhaust temperature in the air-conditioning system, and the allowed maximum target exhaust temperature is less than the maximum exhaust temperature. The difference can be determined based on experiments or experience. For example, the allowed maximum target exhaust temperature can be set 2°C lower than the maximum exhaust temperature.

[0054] For example, taking the first target exhaust temperature as P1, the second target exhaust temperature as P2, the maximum exhaust temperature as A, and the preset exhaust temperature as the allowed maximum target exhaust temperature P max , P max which is A - 2 for illustration. After obtaining the second target exhaust temperature P2, compare the second target exhaust temperature P2 with the allowed maximum target exhaust temperature P max . When P2 < A - 2, reduce the opening degree of the electronic expansion valve based on the second target exhaust temperature P2. When P2 ≥ A - 2, use the allowed maximum target exhaust temperature A - 2 as the second target exhaust temperature P2, and reduce the opening degree of the electronic expansion valve based on the allowed maximum target exhaust temperature A - 2.

[0055] Furthermore, the step of "increasing the opening degree of the electronic expansion valve" specifically includes: Obtain the first target exhaust temperature. Calculate the difference between the first target exhaust temperature and the preset temperature reduction to obtain the third target exhaust temperature; Based on the third target exhaust temperature, increase the opening of the electronic expansion valve.

[0056] It should be noted that, based on the third target exhaust temperature, the opening of the electronic expansion valve is increased. Specifically, this includes: increasing the opening of the electronic expansion valve based on the third target exhaust temperature until the exhaust temperature reaches the third target exhaust temperature; then, using the third target exhaust temperature as the adjustment target, controlling the opening of the electronic expansion valve to maintain the actual exhaust temperature at the third target exhaust temperature.

[0057] For example, let's describe the adjustment process of an air conditioning system starting up and entering the second operating mode for the first time, with a first target exhaust temperature of P1, a third target exhaust temperature of P3, and a preset temperature reduction ΔP2 of 1℃. When ΔT1 < 0℃, the first target exhaust temperature P1 is obtained, and the difference between the first target exhaust temperature P1 and the preset temperature reduction ΔP2 (1℃) is calculated to obtain the third target exhaust temperature P3. Since the third target exhaust temperature P3 is 1℃ lower than the first target exhaust temperature P1, the opening of the electronic expansion valve is increased based on the third target exhaust temperature P3, so that the actual exhaust temperature reaches the third target exhaust temperature P3. Subsequently, the opening of the electronic expansion valve is dynamically adjusted with the third target exhaust temperature P3 as the adjustment target to maintain the actual exhaust temperature at the third target exhaust temperature P3.

[0058] To illustrate further, let's take a first set time of 6 minutes and a first temperature difference threshold ΔT. 1 The second temperature difference threshold ΔT is 1℃. 2 Taking an air conditioning system operating in its second mode as an example, with a target exhaust temperature of 0℃, a third target exhaust temperature of P3, a preset temperature increment ΔP1 of 1℃, and a preset temperature decrement ΔP2 of 1℃, the subsequent adjustment process is explained. When ΔT1 < 0℃, the first target exhaust temperature P1 is obtained, and the difference between the first target exhaust temperature P1 and the preset temperature decrement ΔP2 (1℃) is calculated to obtain the third target exhaust temperature P3. Based on the third target exhaust temperature, the opening of the electronic expansion valve is increased. After 6 minutes, when ΔT2 < 0℃, the third target exhaust temperature of the previous adjustment cycle is used as the first target exhaust temperature P1 for the current adjustment cycle. The difference between this first target exhaust temperature P1 and the preset temperature decrement ΔP2 (1℃) is calculated to obtain the new third target exhaust temperature P3. Based on this third target exhaust temperature P3, the opening of the electronic expansion valve is increased so that the actual exhaust temperature reaches the third target exhaust temperature P3. Subsequently, the opening of the electronic expansion valve is dynamically adjusted with the third target exhaust temperature P3 as the adjustment target to maintain the actual exhaust temperature at the third target exhaust temperature P3.

[0059] To illustrate further, let's take a first set time of 6 minutes and a first temperature difference threshold ΔT.1 The second temperature difference threshold ΔT is 1℃. 2 Taking an air conditioning system operating in its second mode as an example, with a target exhaust temperature of 0℃, a first target exhaust temperature of P1, a second target exhaust temperature of P2, a third target exhaust temperature of P3, a preset temperature increment ΔP1 of 1℃, and a preset temperature decrement ΔP2 of 1℃, the subsequent adjustment process is explained. When ΔT1 ≥ 1℃, the first target exhaust temperature P1 is obtained. The sum of the first target exhaust temperature P1 and the preset temperature increment ΔP1 (1℃) is calculated to obtain the second target exhaust temperature P2. Based on the second target exhaust temperature, the opening of the electronic expansion valve is reduced. After 6 minutes, when ΔT2 < 0℃, the second target exhaust temperature of the previous adjustment cycle is used as the first target exhaust temperature P1 of the current adjustment cycle. The difference between the first target exhaust temperature P1 and the preset temperature decrement ΔP2 (1℃) is calculated to obtain the third target exhaust temperature P3. Based on the third target exhaust temperature P3, the opening of the electronic expansion valve is increased so that the actual exhaust temperature reaches the third target exhaust temperature P3; then, the opening of the electronic expansion valve is dynamically adjusted with the third target exhaust temperature P3 as the adjustment target so that the actual exhaust temperature is maintained at the third target exhaust temperature P3.

[0060] To illustrate further, let's take a first set time of 6 minutes and a first temperature difference threshold ΔT. 1 The second temperature difference threshold ΔT is 1℃. 2 Taking a target exhaust temperature of 0℃, a first target exhaust temperature of P1, a third target exhaust temperature of P3, and a preset temperature reduction ΔP2 of 1℃ as an example, the subsequent adjustment process after the air conditioning system enters the second operating mode is explained. When 1℃ ≥ ΔT1 ≥ 0℃, the target exhaust temperature remains unchanged. After 6 minutes, when ΔT2 < 0℃, the target exhaust temperature of the previous adjustment cycle is used as the first target exhaust temperature P1 for the current adjustment cycle. The difference between this first target exhaust temperature P1 and the preset temperature reduction ΔP2 (1℃) is calculated to obtain the third target exhaust temperature P3. Based on this third target exhaust temperature P3, the opening of the electronic expansion valve is increased so that the actual exhaust temperature reaches the third target exhaust temperature P3. Subsequently, the opening of the electronic expansion valve is dynamically adjusted with the third target exhaust temperature P3 as the adjustment target to maintain the actual exhaust temperature at the third target exhaust temperature P3.

[0061] Furthermore, after the step of controlling the opening adjustment of the electronic expansion valve, the following is also included: Obtain multiple first coil temperatures within the current adjustment cycle and multiple second coil temperatures from the previous adjustment cycle; Calculate the first average value of the temperatures of multiple first coils and the second average value of the temperatures of multiple second coils; Calculate the difference between the first average and the second average; Compare the difference with the preset difference; If the difference is less than the preset difference, then count the number of times. If the cumulative number of times within the preset time period is greater than or equal to the preset number of times, the operation of reducing the opening of the electronic expansion valve will be stopped. The preset difference is less than or equal to zero.

[0062] It should be noted that, to simplify the calculation of the above average values, the highest and lowest values ​​of the coil temperature within each adjustment cycle can also be used directly. For example, the average value can be calculated using the highest and lowest values ​​of the coil temperature within each adjustment cycle, with a preset count of 3 and a preset difference of 0. Specifically: Obtain the highest and lowest values ​​of the coil temperature within the current adjustment cycle, as well as the highest and lowest values ​​of the coil temperature within the previous adjustment cycle. Then, calculate the first average value Pavg1 (i.e., the average of the highest and lowest values ​​within this adjustment cycle) for the current adjustment cycle and the second average value Pavg2 (i.e., the average of the highest and lowest values ​​within this adjustment cycle) for the previous adjustment cycle. Next, calculate the difference ΔP between the first average value Pavg1 and the second average value Pavg2, and compare the difference ΔP with the preset difference ΔP0. When ΔP < 0, count the occurrences and record the cumulative count. If the cumulative number of occurrences (n) reaches 3 or more within a preset time period, it indicates a risk of reduced heating capacity due to excessive valve closure and potential evaporator frosting due to insufficient refrigerant flow. Therefore, the operation of reducing the opening of the electronic expansion valve will be stopped. The coil temperature refers to the evaporator coil temperature.

[0063] Furthermore, the step of "stopping the operation of reducing the opening of the electronic expansion valve" may include, or be performed simultaneously with, the following: Increase the opening of the electronic expansion valve, or maintain the target exhaust temperature.

[0064] It should be noted that, within a preset time period, if the difference between the average coil temperature in the current adjustment cycle and the average coil temperature in the previous adjustment cycle is less than a preset difference, and the cumulative number of such differences reaches a preset number, then after stopping the step of reducing the opening of the electronic expansion valve, or simultaneously, the opening of the electronic expansion valve is increased, or the target exhaust temperature is maintained unchanged. This can eliminate the risk of evaporator frosting caused by reduced heating capacity and insufficient refrigerant flow due to excessive valve closure. The steps of increasing the opening of the electronic expansion valve or maintaining the target exhaust temperature unchanged are as described above and will not be repeated here.

[0065] In one embodiment, after the air conditioning system enters the second operating mode, the control method further includes: Obtain the compressor's second operating frequency f2; Determine whether the second operating frequency f2 is equal to the first operating frequency f1; When the second operating frequency f2 is not equal to the first operating frequency f1, the air conditioning system is switched to the first operating mode.

[0066] It should be noted that the second operating mode requires the compressor operating frequency to be stable. When the compressor operating frequency changes, the air conditioning system exits the second operating mode to avoid regulation disturbances or system malfunctions. Once the compressor operating frequency stabilizes and the conditions for entering the second operating mode are met again, the air conditioning system can re-enter the second operating mode.

[0067] For example, let's consider a second set time of 2 minutes and a third set time of 6 minutes. After the air conditioning system starts operating in the second mode, it acquires the second operating frequency f2 every 2 minutes and determines whether the second operating frequency f2 is equal to the first operating frequency f1. When the second operating frequency f2 equals the first operating frequency f1, it acquires the second operating frequency f2 again after a 2-minute interval, and repeats the above process. When the second operating frequency f2 is not equal to the first operating frequency f1, the air conditioning system switches back to the first operating mode. After the air conditioning system exits the second operating mode, it acquires the first operating frequency f1 every 6 minutes and re-determines whether the trigger conditions for entering the second operating mode are met.

[0068] The following is combined Figure 1 A brief description of one possible operating process of the air conditioning system of this application is provided.

[0069] like Figure 1 As shown, in one possible operation:

[0070] S201, in response to the received heating command, control the air conditioning system to operate in the first operating mode, and then execute S202.

[0071] S202, obtain the compressor's first operating frequency f1, and then execute S203.

[0072] S203, record the duration t of the compressor running at the first operating frequency f1, and then execute S204.

[0073] S204, determine if t≥6min is true? If true, execute S205; otherwise, if false, execute S202.

[0074] S205, the air conditioning system meets the trigger conditions for entering the second operating mode, and then S206 is executed.

[0075] S206, obtain the first intermediate temperature K1, the first return gas temperature C1 of the compressor and the first target exhaust temperature P1, and then execute S207.

[0076] S207, calculate the first temperature difference ΔT1 between the first middle road temperature K1 and the first return air temperature C1, and then execute S208.

[0077] S208, determine whether ΔT1≥1℃ holds? If it holds, execute S209; otherwise, if it does not hold, execute S213.

[0078] S209, calculate the sum of the first target exhaust temperature P1 and the preset temperature increment ΔP1 (1℃) as the second target exhaust temperature P2, and then execute S210.

[0079] S210, determine whether P2<A - 2 holds? If it holds, execute S211; otherwise, if it does not hold, execute S212.

[0080] S211, based on the second target exhaust temperature P2, reduce the opening of the electronic expansion valve while maintaining the first operating frequency f1 unchanged, and then execute S217 and S223.

[0081] S212, based on the maximum target exhaust temperature A - 2, reduce the opening of the electronic expansion valve while maintaining the first operating frequency f1 unchanged, and then execute S217 and S223.

[0082] S213, determine whether 1℃>ΔT1≥0℃ holds? If it holds, execute S214; otherwise, if it does not hold, execute S215.

[0083] S214, maintain the current target exhaust temperature of the compressor and the first operating frequency f1 unchanged, and then execute S217 and S223.

[0084] S215, calculate the difference between the first target exhaust temperature P1 and the preset temperature reduction ΔP2 (1℃) to obtain the third target exhaust temperature P3, and then execute S216.

[0085] S216, based on the third target exhaust temperature P3, increase the opening of the electronic expansion valve while maintaining the first operating frequency f1 unchanged, and then execute S217 and S223.

[0086] S217, after 6 minutes, obtain the second middle road temperature K2 and the second return air temperature C2, and then execute S218.

[0087] S218, calculate the second temperature difference ΔT2 between the second middle road temperature K2 and the second return air temperature C2, and then execute S219.

[0088] S219, determine whether ΔT2<0℃ holds? If it holds, execute S220; otherwise, if it does not hold, execute S221.

[0089] S220, take the target exhaust temperature of the previous adjustment cycle as the first target exhaust temperature P1 of the current adjustment cycle, and then execute S215.

[0090] S221, determine whether 1℃>ΔT2≥0℃ is true? If true, execute S214; otherwise, if false, execute S222.

[0091] S222, take the target exhaust temperature of the previous adjustment cycle as the first target exhaust temperature P1 of the current adjustment cycle, and then execute S209.

[0092] S223: Obtain the highest and lowest values ​​of the coil temperature in the current adjustment cycle, as well as the highest and lowest values ​​of the coil temperature in the previous adjustment cycle, and then execute S224.

[0093] S224, calculate the first average value Pavg1 of the highest and lowest values ​​of the coil temperature in the current adjustment cycle and the second average value Pavg2 of the highest and lowest values ​​of the coil temperature in the previous adjustment cycle, and then execute S225.

[0094] S225, calculate the difference ΔP between the first average value Pavg1 and the second average value Pavg2, and then execute S226.

[0095] S226, Determine if the difference ΔP < 0℃ is true. If true, execute S227; otherwise, execute S223.

[0096] S227, count the number of times n is accumulated, and then execute S228.

[0097] S228, Determine if the condition is true for n≥3 times within a preset time period. If true, execute S229; otherwise, execute S223.

[0098] S229, stop the operation of reducing the opening of the electronic expansion valve, and then execute S214.

[0099] Those skilled in the art will understand that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of this application and form different embodiments. For example, any of the claimed embodiments in the claims of this application can be used in any combination.

[0100] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, 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 scope of protection of the present invention.

Claims

1. A control method for an air conditioning system, characterized in that, The control method includes: In response to a received heating command, the air conditioning system is controlled to operate in a first operating mode; wherein, the first operating mode is a normal operating mode; Obtain the first operating frequency f1 of the compressor in the air conditioning system; Based on the first operating frequency f1, determine whether the air conditioning system meets the triggering conditions for entering the second operating mode; When the triggering condition is met, the first intermediate temperature K1 of the condenser and the first return gas temperature C1 of the compressor in the air conditioning system are obtained. Calculate the first temperature difference ΔT1 between the first intermediate temperature K1 and the first return gas temperature C1; The opening degree of the electronic expansion valve in the air conditioning system is controlled according to the temperature difference range in which the first temperature difference ΔT1 is located.

2. The control method according to claim 1, characterized in that, The step of "controlling the opening degree of the electronic expansion valve in the air conditioning system according to the temperature range in which the first temperature difference ΔT1 is located" further includes: When ΔT1≥ ΔT 1 the opening degree of the electronic expansion valve is reduced while the operating frequency of the compressor is maintained unchanged. If ΔT 1 >ΔT1≥ΔT 2 At the same time, the current target exhaust temperature and operating frequency of the compressor are maintained unchanged; If ΔT1 < ΔT 2 At the same time, the opening of the electronic expansion valve is increased while the operating frequency of the compressor remains constant; Where, ΔT 1 The first temperature difference threshold, ΔT 2 This is the second temperature difference threshold.

3. The control method according to claim 2, characterized in that, The step of "controlling the opening adjustment of the electronic expansion valve in the air conditioning system" further includes: After a first set time, the second intermediate temperature K2 and the second return gas temperature C2 are obtained; Calculate the second temperature difference ΔT2 between the second intermediate temperature K2 and the second return gas temperature C2; Compare the second temperature difference ΔT2 and the first temperature difference threshold ΔT respectively. 1 Second temperature difference threshold ΔT 2 Size; When ΔT2≥ΔT 1 If the opening of the electronic expansion valve is reduced, the operating frequency of the compressor will remain unchanged. If ΔT 1 >ΔT2≥ΔT 2 Then the current target exhaust temperature and operating frequency of the compressor will remain unchanged; If ΔT2 < ΔT 2 If the opening of the electronic expansion valve is increased, the operating frequency of the compressor will remain unchanged. Repeat the above steps until the air conditioning system exits the second operating mode.

4. The control method according to claim 2 or 3, characterized in that, The step of "reducing the opening of the electronic expansion valve" specifically includes: Obtain the first target exhaust temperature; The second target exhaust temperature is obtained by summing the first target exhaust temperature and the preset temperature increment. Based on the second target exhaust temperature, the opening of the electronic expansion valve is reduced.

5. The control method according to claim 4, characterized in that, The step of "reducing the opening of the electronic expansion valve based on the second target exhaust temperature" includes the following: Compare the second target exhaust temperature with the preset exhaust temperature; When the second target exhaust temperature is lower than the preset exhaust temperature, the opening of the electronic expansion valve is reduced based on the second target exhaust temperature. When the second target exhaust temperature is greater than or equal to the preset exhaust temperature, the opening of the electronic expansion valve is reduced based on the preset exhaust temperature.

6. The control method according to claim 2 or 3, characterized in that, The specific steps of "increasing the opening degree of the electronic expansion valve" include: Obtain the first target exhaust temperature; Calculate the difference between the first target exhaust temperature and the preset temperature reduction to obtain the third target exhaust temperature; Based on the third target exhaust temperature, the opening of the electronic expansion valve is increased.

7. The control method according to claim 2 or 3, characterized in that, The step of controlling the opening adjustment of the electronic expansion valve further includes: Obtain multiple first coil temperatures within the current adjustment cycle and multiple second coil temperatures from the previous adjustment cycle; Calculate the first average temperature of the plurality of first coils and the second average temperature of the plurality of second coils; Calculate the difference between the first average and the second average; Compare the difference with a preset difference. If the difference is less than a preset difference, then a count is performed and the cumulative number of counts is recorded; If the cumulative number of times within the preset time period is greater than or equal to the preset number of times, the operation of reducing the opening of the electronic expansion valve will be stopped. Wherein, the preset difference is less than or equal to zero.

8. The control method according to claim 7, characterized in that, The steps of "stopping the operation of reducing the opening of the electronic expansion valve" may include, or be performed simultaneously with, the following: Increase the opening of the electronic expansion valve, or maintain the target exhaust temperature unchanged.

9. The control method according to claim 1, characterized in that, The triggering condition is that the compressor runs continuously at a first operating frequency f1 for a preset duration.

10. The control method according to claim 1, characterized in that, After the air conditioning system enters the second operating mode, the control method further includes: Obtain the second operating frequency f2 of the compressor; Determine whether the second operating frequency f2 is equal to the first operating frequency f1; When the second operating frequency f2 is not equal to the first operating frequency f1, the air conditioning system is controlled to switch to the first operating mode.

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