Method and device for controlling initial opening degree of electronic expansion valve

Abstract

The application discloses an initial opening degree control method and device of an electronic expansion valve, and is applied to a multi-connected air conditioner system with the electronic expansion valve arranged in an outdoor unit. The method comprises the following steps: obtaining capacity information of a target indoor unit, indoor and outdoor environment temperatures; selecting a corresponding current coefficient set from a plurality of sets of preset coefficient sets according to the capacity information, wherein the set at least comprises main adjustment, inner loop temperature influence and outer loop temperature influence coefficients; and determining the initial opening degree of the electronic expansion valve through a predetermined calculation formula based on the selected coefficients and the obtained temperatures. The application solves the problem that a unified initial opening degree cannot accurately adapt to indoor units with different capacities, realizes differentiated initial flow distribution, and improves the operation reliability and energy efficiency of the system.

Description

Technical Field

[0001] This invention relates to the field of air conditioning technology, and more specifically, to a method and related device for controlling the initial opening degree of an electronic expansion valve in a multi-split air conditioning system. Background Technology

[0002] Multi-split air conditioning systems are widely used because they can flexibly meet the independent temperature control needs of different areas. In these systems, the electronic expansion valve, as a key throttling component, directly affects the refrigerant flow rate, thus impacting the system's cooling or heating performance and operational energy efficiency. Therefore, the initial opening setting of the electronic expansion valve is crucial to ensure that the system can quickly reach a stable and efficient operating state during startup or initial switching between operating conditions.

[0003] In some multi-split air conditioning system designs, to simplify the structure or reduce costs, the electronic expansion valve may be centrally located in the outdoor unit, and a uniform model of electronic expansion valve may be used to serve multiple indoor units connected to that outdoor unit. This configuration, especially in so-called "fixed-split" models, where each indoor unit does not have an independently adjustable electronic expansion valve but shares the same electronic expansion valve located on the outdoor unit for flow distribution, presents some challenges. Since different indoor units often have different cooling or heating capacity requirements, if a fixed initial opening degree, or the same initial opening degree based on simple logical calculations, is used for all refrigerant flow paths leading to indoor units of different capacities, it is difficult to accurately match the actual flow requirements of each indoor unit at the initial startup stage.

[0004] Specifically, when using the same initial opening degree, smaller capacity indoor units may receive excessive refrigerant flow, exceeding their evaporation or condensation capacity. This could lead to risks such as excessively high evaporation pressure during cooling and liquid return during heating, affecting the stable operation of the system and the lifespan of the compressor. Conversely, larger capacity indoor units may receive insufficient initial refrigerant flow, resulting in slow start-up of cooling or heating performance, reduced user comfort, and potentially causing the system to operate in a low-efficiency state for an extended period before reaching its target state.

[0005] Therefore, under the premise of fixed electronic expansion valve model and physical location, how to set a more reasonable and differentiated initial opening degree for different indoor units according to their actual capacity requirements, so as to improve the accuracy of flow distribution at the initial stage of system startup, avoid the above-mentioned problems, and improve the overall operational reliability, comfort and energy efficiency of the system, is a technical problem that urgently needs to be solved in the field of air conditioning control technology. Summary of the Invention

[0006] The main objective of this invention is to provide a method and apparatus for controlling the initial opening of an electronic expansion valve, aiming to solve the technical problem in the prior art where, when electronic expansion valves are installed on outdoor units of the same model, it is difficult to adapt to the needs of indoor units with different capacities by using a uniform initial opening, resulting in inaccurate flow distribution and affecting the stability and efficiency of system operation.

[0007] To achieve the above objectives, this invention provides a method for controlling the initial opening of an electronic expansion valve. This method is applied to multi-split air conditioning systems where the electronic expansion valve is located on the outdoor unit and all units are of the same model. The method first requires acquiring the capacity information of the target indoor unit, as well as the indoor and outdoor ambient temperatures of the target indoor unit and the outdoor unit. Next, based on the acquired capacity information of the target indoor unit, the system selects a set of coefficients corresponding to the current situation from at least two pre-set sets of coefficients. Each of these pre-set sets of coefficients includes at least one main control coefficient, an inner loop temperature influence coefficient related to the indoor ambient temperature, and an outer loop temperature influence coefficient related to the outdoor ambient temperature. After selecting a suitable set of coefficients, the initial opening of the electronic expansion valve is determined based on the coefficients in this set, combined with the acquired indoor and outdoor ambient temperatures, using a predetermined calculation formula. This calculated initial opening better adapts to the specific operating requirements of the target indoor unit, thereby achieving more precise initial flow control.

[0008] In one specific implementation, the aforementioned predetermined calculation formula can be expressed as follows: the initial opening degree of the electronic expansion valve is equal to the main control coefficient P multiplied by the expression within parentheses, then multiplied by the preset constant C2 and divided by the preset constant C3. The expression within parentheses is the preset constant C1 minus the product of the inner ring temperature influence coefficient K_inner ring and the indoor ambient temperature T_inner ring, plus the product of the outer ring temperature influence coefficient K_outer ring and the outdoor ambient temperature T_outer ring. In this formula, P represents the main control coefficient in the current coefficient set, K_inner ring represents the inner ring temperature influence coefficient in the current coefficient set, K_outer ring represents the outer ring temperature influence coefficient in the current coefficient set, T_inner ring is the obtained indoor ambient temperature, T_outer ring is the obtained outdoor ambient temperature, and C1, C2, and C3 are preset constants. As a preferred implementation, the value of the preset constant C1 can be set to 75, the value of the preset constant C2 can be set to 480, and the value of the preset constant C3 can be set to 100.

[0009] To more precisely match indoor units of different capacities, the at least two sets of preset coefficients can be designed to be pre-set for different preset capacity ranges where the capacity information of the target indoor unit falls. For example, these different preset capacity ranges can be specifically divided into: a first capacity range, whose capacity value is less than or equal to 12 standard capacity units; a second capacity range, whose capacity value is greater than 12 standard capacity units and less than or equal to 18 standard capacity units; and a third capacity range, whose capacity value is greater than 18 standard capacity units.

[0010] Accordingly, in a specific coefficient setting scheme, if the capacity information of the target indoor unit falls within the aforementioned first capacity range, the current coefficient set selected by the system will result in a main control coefficient P of 0.7, an inner loop temperature influence coefficient Kinner loop of 0.7, and an outer loop temperature influence coefficient Kouter loop of 1.9. If the capacity information of the target indoor unit falls within the second capacity range, the current coefficient set selected will result in a main control coefficient P of 0.8. If the capacity information of the target indoor unit falls within the third capacity range, the current coefficient set selected will result in a main control coefficient P of 0.9. In this way, indoor units with different capacities can automatically match different adjustment parameters, thereby calculating differentiated initial opening degrees.

[0011] Furthermore, to ensure that the actual opening degree of the electronic expansion valve is within a reasonable range, the method of the present invention may also include an opening degree limiting step. This involves comparing the initial opening degree determined by a predetermined calculation formula with a preset minimum initial opening degree value and a preset maximum initial opening degree value. If the calculated initial opening degree is less than the minimum initial opening degree value, the initial opening degree of the electronic expansion valve is ultimately set to the minimum initial opening degree value; conversely, if the calculated initial opening degree is greater than the maximum initial opening value, it is ultimately set to the maximum initial opening value.

[0012] Considering that multi-split air conditioning systems may operate in different modes, such as heating-only operation mode or heating-multiple operation mode, the method of this invention also allows for different coefficient strategies to be adopted for these different modes. Specifically, when the system is in heating-only operation mode, at least two preset coefficient sets used to select the current coefficient set can be defined as a first type of preset coefficient set; while when the system is in heating-multiple operation mode, a second type of preset coefficient set can be used. In these two types of preset coefficient sets, the values ​​of the corresponding coefficients for the same capacity range can be set to the same, or they can be set to different values ​​according to actual needs.

[0013] To implement the above method, the present invention also provides an initial opening control device for an electronic expansion valve. This device is also applied to multi-split air conditioning systems where the electronic expansion valve is located on the outdoor unit and of the same model. The device mainly includes an information acquisition module, a coefficient selection module, and an opening calculation module. The information acquisition module is responsible for acquiring the capacity information of the target indoor unit, as well as the indoor ambient temperature of the target indoor unit and the outdoor ambient temperature of the outdoor unit. The coefficient selection module, based on the capacity information of the target indoor unit acquired by the information acquisition module, selects a corresponding current coefficient set from at least two preset coefficient sets. The composition of these coefficient sets is consistent with that described in the aforementioned method. Finally, the opening calculation module, based on the coefficients in the current coefficient set selected by the coefficient selection module, and the indoor and outdoor ambient temperatures acquired by the information acquisition module, determines the initial opening of the electronic expansion valve using a predetermined calculation formula to adapt to the operating requirements of the target indoor unit. In a preferred embodiment, the predetermined calculation formula used by the opening calculation module is the same as the formula described in the aforementioned method, and the values ​​of the preset constants C1, C2, and C3 used therein are also consistent with the preferred values ​​in the aforementioned method.

[0014] By adopting the technical solution provided by this invention, a more precise initial opening degree of the electronic expansion valve can be dynamically calculated and set according to the specific capacity of each target indoor unit and the current indoor and outdoor ambient temperature. This not only effectively solves the problem of uneven flow distribution caused by fixed or simple initial opening degree strategies, avoiding situations where there is too much refrigerant in small-capacity indoor units and insufficient refrigerant in large-capacity indoor units, but also helps to improve the stability and rapid response capability of the system startup, and reduces potential operational risks caused by improper initial settings, such as liquid return, thereby comprehensively improving the operational reliability, user comfort, and overall energy efficiency of multi-split air conditioning systems. Attached Figure Description

[0015] Fig. 1 A flowchart illustrating an initial opening control method for an electronic expansion valve provided in this embodiment of the invention.

[0016] Fig. 2 A schematic block diagram of the structure of an electronic expansion valve initial opening control device provided in this embodiment of the invention. Detailed Implementation

[0017] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0018] Example 1.

[0019] This invention discloses a method and apparatus for controlling the initial opening of an electronic expansion valve, particularly suitable for multi-split air conditioning systems where the electronic expansion valves are centrally located on the outdoor unit and are of uniform model. In this system configuration, providing a suitable initial refrigerant flow rate at the start-up stage, based on the different capacity requirements of each indoor unit, is crucial for improving system performance.

[0020] Please see Fig. 1 This diagram illustrates a flowchart of an initial opening control method for an electronic expansion valve provided by an embodiment of the present invention. The method mainly includes the following steps: Step S101: Obtain the capacity information, indoor ambient temperature (T inner ring), and outdoor ambient temperature (T outer ring) of the target indoor unit. In a multi-split air conditioning system, when it is necessary to set the initial opening of the electronic expansion valve for one or more target indoor units, the control system first needs to accurately identify the design capacity of each target indoor unit. This capacity information can be a parameter pre-stored in the system, such as the rated capacity value in kW or HP. Simultaneously, the control system also needs to obtain the indoor ambient temperature of the space where the target indoor unit is located, and the outdoor ambient temperature of the environment where the outdoor unit is located, through corresponding temperature sensors. This information is crucial for subsequent calculations of differentiated initial openings.

[0021] Step S102: Based on the acquired capacity information of the target indoor unit, select a corresponding current coefficient set from at least two preset coefficient sets. A core idea of ​​this invention is to employ different adjustment strategies for indoor units with different capacities. To this end, the system presets multiple coefficient sets. As shown in Table 1, this logical relationship can be represented as a lookup table or a set of conditional judgments.

[0022] Indoor unit capacity k (standard capacity unit) Main adjustment coefficient (P) Inner loop temperature influence coefficient (Kinner loop) Outer loop temperature influence coefficient (Kouter loop) ≤12 0.7 0.7 1.9 > 12 and ≤ 18 0.8 (Example value: 0.7) (Example value: 1.9) >18 0.9 (Example value: 0.7) (Example value: 1.9) Table 1 For example, based on the indoor unit's capacity k, it is divided into different capacity ranges, each corresponding to a specific set of coefficients. Each preset set of coefficients includes at least one main control coefficient P, an inner loop temperature influence coefficient K_inner loop related to the indoor ambient temperature T_inner loop, and an outer loop temperature influence coefficient K_outer loop related to the outdoor ambient temperature T_outer loop. Unlike existing technologies that may use a single fixed coefficient or simply adjust linearly based on capacity, this invention introduces a combination of multi-dimensional coefficients. The selection of these coefficients is directly linked to the specific capacity range of the indoor unit, and the influence of indoor and outdoor ambient temperatures on the initial opening requirement is carefully considered to achieve more accurate initial flow matching.

[0023] Step S103: Based on the coefficients in the selected current coefficient set, the obtained indoor ambient temperature, and the outdoor ambient temperature, the initial opening degree of the electronic expansion valve is determined using a predetermined calculation formula. After determining the coefficient set to be used by the current target indoor unit, these coefficients, along with the T inner ring and T outer ring values ​​obtained in step S101, can be substituted into a predetermined calculation formula. In a preferred embodiment of the present invention, this predetermined calculation formula can be specifically expressed as follows: The initial opening of the electronic expansion valve = P × (C1 - K inner ring × T inner ring + K outer ring × T outer ring) × C2 / C3.

[0024] C1, C2, and C3 are preset constants. For example, C1 can be 75, C2 can be 480, and C3 can be 100. This formula structure is not a simple linear superposition, but comprehensively considers the basic offset (represented by C1), temperature compensation (represented by K inner loop × T inner loop and K outer loop × T outer loop), and the main regulating effect of the capacity level (represented by P), and performs overall scaling through C2 / C3. This multi-factor, non-simple linear combination calculation method, compared with some technical solutions that only consider capacity and a single ambient temperature for linear interpolation or simple product regulation (such as some solutions that may only look up an initial opening degree and a capacity regulation coefficient based on outdoor operating conditions and then perform linear calculations), can more comprehensively and meticulously reflect the optimal initial opening degree under different operating conditions and different capacity requirements, thereby achieving higher precision control.

[0025] Specifically, in one possible implementation, the capacity of the indoor unit can be divided into multiple intervals. For example, the first capacity interval can be defined as a capacity value less than or equal to 12 standard capacity units; the second capacity interval is defined as a capacity value greater than 12 standard capacity units and less than or equal to 18 standard capacity units; and the third capacity interval is defined as a capacity value greater than 18 standard capacity units. Different combinations of coefficients can be set for these different capacity intervals. For example, when the capacity information of the target indoor unit is in the first capacity interval, the selected current coefficient set can make the value of the main adjustment coefficient P 0.7, the value of the inner loop temperature influence coefficient K_inner loop 0.7, and the value of the outer loop temperature influence coefficient K_outer loop 1.9. When the capacity information of the target indoor unit is in the second capacity interval, the value of the main adjustment coefficient P can be adjusted to 0.8, while the values ​​of the inner and outer loop temperature influence coefficients can be adjusted accordingly based on experimental data or design experience or remain unchanged. Similarly, when in the third capacity interval, the value of the main adjustment coefficient P can be further adjusted to 0.9. By employing this segmented and coefficient-based refined adjustment strategy, this invention ensures that indoor units of different capacities can achieve an initial opening degree that better matches their own characteristics, even under the same ambient temperature. Compared to some existing technologies that may use the same set of basic opening parameters and adjustment logic for all capacities, scaling only proportionally based on capacity, this invention offers greater adaptability and accuracy, and better avoids the problems of "oversupply" for small-capacity indoor units and "undersupply" for large-capacity indoor units.

[0026] To further optimize control, the method of the present invention may also include an opening limitation step (not included in...). Fig. 1 (This is shown separately, but can be considered as a follow-up process to step S103). That is, the initial opening calculated using the above formula is compared with a preset minimum initial opening value (e.g., to prevent the valve from closing completely or the flow rate from being too low) and a preset maximum initial opening value (e.g., to prevent the flow rate from being too high or exceeding the system's capacity). If the calculated value is less than the minimum value, the minimum value is ultimately adopted; if the calculated value is greater than the maximum value, the maximum value is ultimately adopted. This ensures that the initial opening is always within a safe and effective operating range.

[0027] Furthermore, considering that the initial opening requirements of an air conditioning system may differ under different operating modes (such as heating on-only or heating on-multiple modes), the method of this invention allows for the configuration of different preset coefficient sets (first type and second type preset coefficient sets) for different operating modes. This means that even for the same indoor unit, the coefficients used to calculate the initial opening may differ under different operating modes, thereby achieving more comprehensive adaptability to operating conditions.

[0028] Please see Fig. 2This diagram illustrates a schematic block diagram of an electronic expansion valve initial opening control device 200 provided in an embodiment of the present invention. The device 200 can be integrated into the outdoor unit controller of a multi-split air conditioning system. The device 200 includes: The information acquisition module 201, corresponding to step S101 in the method flow, is used to acquire the capacity information, indoor ambient temperature (T inner ring), and outdoor ambient temperature (T outer ring) of the target indoor unit. This module may include interfaces with sensors and system storage units.

[0029] The coefficient selection module 202 corresponds to step S102 in the method flow. This module internally stores or can access multiple preset coefficient sets, and selects the coefficient set to be used based on the indoor unit capacity information provided by the information acquisition module 201.

[0030] The opening calculation module 203 corresponds to step S103 in the method flow. This module receives temperature information from the information acquisition module 201 and the current coefficient set from the coefficient selection module 202, and uses a predetermined calculation formula (as described above) to calculate the initial opening of the electronic expansion valve.

[0031] Optionally, the device may also include an opening adjustment and output module (not shown separately) for performing opening limit logic and sending the final determined initial opening command to the drive mechanism of the electronic expansion valve.

[0032] The method and apparatus provided by this invention significantly improve the setting accuracy of the initial opening degree of the electronic expansion valve in multi-split air conditioning systems with fixed outdoor unit models. Its core advantage lies in its innovative approach: it not only considers the indoor unit capacity itself, but also segments the indoor unit capacity and assigns a unique parameter combination to each segment, including the main control coefficient, the inner loop temperature influence coefficient, and the outer loop temperature influence coefficient. This, combined with the actual indoor and outdoor ambient temperatures, is used to determine the initial opening degree through a comprehensive calculation formula. This multi-dimensional and refined control strategy can more effectively address the specific needs of indoor units of different capacities under different environmental conditions, ensuring that each indoor unit receives near-ideal refrigerant flow at startup. This effectively avoids the problems of excessive flow in small-capacity indoor units and insufficient flow in large-capacity indoor units under traditional fixed opening or simple proportional adjustment methods. The resulting technical effects include smoother system startup, faster achievement of set conditions, more reliable operation (e.g., reduced risk of liquid return), higher user comfort, and potential energy efficiency improvements. Compared to some schemes that rely solely on indoor unit capacity and a single external operating condition (such as outdoor temperature) to look up a table or perform simple linear calculations to obtain an adjustment coefficient and a basic opening degree before making adjustments, the multi-parameter (main control, inner loop temperature influence, outer loop temperature influence) adaptive calculation method based on capacity segmentation adopted in this invention has significant improvements in control precision and adaptability to complex operating conditions.

[0033] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for controlling the initial opening degree of an electronic expansion valve, applied to a multi-split air conditioning system where the electronic expansion valve is installed in the outdoor unit and the models are the same, characterized in that... Includes the following steps: The system acquires the capacity information of the target indoor unit; acquires the indoor ambient temperature of the environment where the target indoor unit is located and the outdoor ambient temperature of the environment where the outdoor unit is located; based on the acquired capacity information of the target indoor unit, it selects a corresponding current coefficient set from at least two preset coefficient sets, wherein each preset coefficient set contains at least one main control coefficient, one inner loop temperature influence coefficient related to the indoor ambient temperature, and one outer loop temperature influence coefficient related to the outdoor ambient temperature; based on the coefficients in the selected current coefficient set, the acquired indoor ambient temperature, and the acquired outdoor ambient temperature, it determines the initial opening of the electronic expansion valve through a predetermined calculation formula to adapt to the operating requirements of the target indoor unit.

2. The method according to claim 1, characterized in that, The predetermined calculation formula is as follows: Initial opening of the electronic expansion valve = P × (C1 - K inner ring × T inner ring + K outer ring × T outer ring) × C2 / C3; where P is the main control coefficient in the current coefficient set; K inner ring is the inner ring temperature influence coefficient in the current coefficient set; K outer ring is the outer ring temperature influence coefficient in the current coefficient set; T inner ring is the obtained indoor ambient temperature; T outer ring is the obtained outdoor ambient temperature; C1, C2 and C3 are preset constants.

3. The method according to claim 2, characterized in that, The preset constant C1 has a value of 75, the preset constant C2 has a value of 480, and the preset constant C3 has a value of 100.

4. The method according to claim 2, characterized in that, The at least two sets of preset coefficients are preset for different preset capacity ranges where the capacity information of the target indoor unit is located.

5. The method according to claim 4, characterized in that, The different preset capacity ranges include: a first capacity range, the capacity value of which is less than or equal to 12 standard capacity units; a second capacity range, the capacity value of which is greater than 12 standard capacity units and less than or equal to 18 standard capacity units; and a third capacity range, the capacity value of which is greater than 18 standard capacity units.

6. The method according to claim 5, characterized in that: If the capacity information of the target indoor unit is within the first capacity range, then the selected current coefficient set makes the value of the main adjustment coefficient P 0.7, the value of the inner ring temperature influence coefficient K_inner ring 0.7, and the value of the outer ring temperature influence coefficient K_outer ring 1.9; if the capacity information of the target indoor unit is within the second capacity range, then the selected current coefficient set makes the value of the main adjustment coefficient P 0.

8. If the capacity information of the target indoor unit is within the third capacity range, then the selected current coefficient set makes the value of the main adjustment coefficient P 0.

9.

7. The method according to claim 1, characterized in that, The method further includes: comparing the initial opening determined by the predetermined calculation formula with a preset minimum initial opening value and a preset maximum initial opening value; and if the calculated initial opening is less than the minimum initial opening value, then the initial opening of the electronic expansion valve is finally set to the minimum initial opening value; or, if the calculated initial opening is greater than the maximum initial opening value, then the initial opening of the electronic expansion valve is finally set to the maximum initial opening value.

8. The method according to claim 1, characterized in that, When the multi-split air conditioning system is in heating single-operation mode, at least two preset coefficient sets of the current coefficient set are selected as a first type of preset coefficient set; when the multi-split air conditioning system is in heating multi-operation mode, at least two preset coefficient sets of the current coefficient set are selected as a second type of preset coefficient set; the values ​​of the corresponding coefficients for the corresponding capacity range in the first type of preset coefficient set and the second type of preset coefficient set are set to be the same or different.

9. An initial opening control device for an electronic expansion valve, applied in a multi-split air conditioning system where the electronic expansion valve is installed in the outdoor unit and the models are the same, characterized in that, The device includes: an information acquisition module for acquiring capacity information of the target indoor unit, indoor ambient temperature of the environment where the target indoor unit is located, and outdoor ambient temperature of the environment where the outdoor unit is located; a coefficient selection module for selecting a corresponding current coefficient set from at least two preset coefficient sets based on the acquired capacity information of the target indoor unit, wherein each preset coefficient set includes at least one main control coefficient, one inner loop temperature influence coefficient related to the indoor ambient temperature, and one outer loop temperature influence coefficient related to the outdoor ambient temperature; and an opening degree calculation module for determining the initial opening degree of the electronic expansion valve based on each coefficient in the selected current coefficient set, the acquired indoor ambient temperature, and the acquired outdoor ambient temperature, using a predetermined calculation formula to adapt to the operating requirements of the target indoor unit.

10. The apparatus according to claim 9, characterized in that, The predetermined calculation formula used by the opening calculation module is: Initial opening of the electronic expansion valve = P × (C1 - K inner ring × T inner ring + K outer ring × T outer ring) × C2 / C3; where P is the main control coefficient in the current coefficient set; K inner ring is the inner ring temperature influence coefficient in the current coefficient set; K outer ring is the outer ring temperature influence coefficient in the current coefficient set; T inner ring is the obtained indoor ambient temperature; T outer ring is the obtained outdoor ambient temperature; C1, C2 and C3 are preset constants; the value of the preset constant C1 is 75, the value of the preset constant C2 is 480, and the value of the preset constant C3 is 100.

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