Method and system for adjusting input current of multi-connected air conditioner

Abstract

A method and system for adjusting the input current of a multi-connected air conditioner comprises the following steps that when the multi-connected air conditioner receives a control instruction, the target opening degree of each capillary tube in the control instruction is analyzed; the total target power of each valve controlled to the target opening degree is counted; acquiring input power of each valve as first power, and counting all the first power to obtain total actual power; and judging whether a difference value between the total actual power and the total target power is greater than a difference threshold value, if the difference value is greater than the difference threshold value, acquiring a bus voltage, and adjusting the input current based on the bus voltage. Through precise temperature control and stable system operation, a user can use the multi-connected air conditioner more conveniently and comfortably, frequent manual adjustment is not needed, and the use experience and the satisfaction degree of the user are greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioner control, and particularly to a method and system for regulating the input current of a multi-connected air conditioner. Background Art

[0002] The working principle of a multi-connected air conditioner is that one outdoor unit can deliver refrigerant liquid to several indoor units through pipelines. In a multi-connected air conditioner system, the outdoor unit can adjust the refrigerant circulation amount and the refrigerant flow rate entering each indoor heat exchanger in real time according to the indoor cooling and heating load requirements to achieve precise temperature control. However, since one outdoor unit usually controls multiple indoor units and the temperature requirements of each indoor unit are different, this requires fine differential control of each capillary valve connecting the indoor unit. To achieve this, it is necessary to independently control the valves of each indoor unit to ensure that the refrigerant flow rate of each indoor unit can be adjusted according to its specific temperature requirements.

[0003] However, in actual operation, the phase difference between the voltage and input current controlled by the compressor makes it possible that the refined control requirements may not be met when setting the input current initially. Specifically, when the voltage or current of the outdoor unit is adjusted improperly, it may cause uneven cooling effects of the entire system, thereby affecting the temperature control effect and energy efficiency performance. Therefore, how to accurately control the current and voltage of each capillary valve to achieve fine adjustment of the temperature requirements of each indoor unit has become a key issue in the multi-connected air conditioner system. Summary of the Invention

[0004] Aiming at the above defects, the purpose of the present invention is to provide a method and system for regulating the input current of a multi-connected air conditioner to solve the problem that the air conditioner temperature operation cannot be accurately controlled in a multi-connected air conditioner.

[0005] To achieve this purpose, the present invention adopts the following technical solutions: A method for regulating the input current of a multi-connected air conditioner includes the following steps:

[0006] Step S1: When the multi-connected air conditioner receives a control instruction, parse the target opening degrees of each capillary in the control instruction;

[0007] Step S2: Statistically calculate the total target power for controlling each valve to the target opening degree;

[0008] Step S3: Obtain the input power of each valve as the first power, and statistically calculate all the first powers to obtain the total actual power;

[0009] Step S4: Determine whether the difference between the total actual power and the total target power is greater than the difference threshold. If the difference is greater than the difference threshold, obtain the bus voltage and adjust the input current based on the bus voltage.

[0010] Preferably, the specific steps in step S2 are as follows:

[0011] Step S21: Obtain the adjusted opening degree based on the difference between the original valve opening degree and the target opening degree;

[0012] Step S22: Obtain the valve type coefficient, and obtain the motor torque required for this opening degree adjustment through the valve type coefficient and the adjusted opening degree;

[0013] Step S23: Obtain the rotational speed specification of the valve motor, and obtain the target power of the valve through the motor torque and the rotational speed specification;

[0014] Step S24: Statistically calculate the target power of all valves that need to be adjusted to obtain the total target power.

[0015] Preferably, the calculation formula for the motor torque is as follows:

[0016] T i = K * p * ΔD i * f;

[0017] Where K is the valve type coefficient, p is the pressure when the valve is at the target opening degree, ΔD i is the adjusted opening degree, and f is the friction coefficient;

[0018] The formula for obtaining the target power is as follows:

[0019]

[0020] Where T i is the motor torque of the i-th valve, n is the rotational speed specification, α is the annual coefficient, and β is the constant coefficient for unit conversion of power, torque, and rotational speed.

[0021] Preferably, the bus voltage includes an independent bus voltage and a shared bus voltage;

[0022] When the bus voltage is an independent bus voltage, obtain the weighted average value of the independent bus voltage to adjust the input current;

[0023] When the bus voltage is a shared bus voltage, use the shared bus voltage to adjust the input current.

[0024] Preferably, the formula for adjusting the input current based on the bus voltage in step S4 is as follows:

[0025]

[0026] Where P i is the target power, V d is the bus voltage, and k is the adjustment coefficient.

[0027] Preferably, the following steps are further included:

[0028] Step A1: Return the valve to its original position and re - execute the valve control instruction based on the adjusted current;

[0029] Step A2: Re - obtain the input power of the valve as the second power;

[0030] Step A3: And sum up all the second powers to obtain the corrected total actual power;

[0031] Step A4: Obtain the difference between the corrected total actual power and the total target power as the first difference;

[0032] Step A5: If the first difference is greater than the difference threshold, correct the adjustment coefficient through the PI controller and the first difference.

[0033] Preferably, the formula for correcting the adjustment coefficient in step A5 is as follows:

[0034]

[0035] where θ is a constant coefficient, K p and K i are the gain coefficients of the PI controller, e is the current first difference, is the average value of the historical first differences, and t is the number of corrections.

[0036] A regulation system for the input current of a multi - connected air conditioner, using the above - mentioned method for regulating the input current of a multi - connected air conditioner, includes an instruction parsing module, a first statistics module, a second statistics module, and a calculation and regulation module;

[0037] The instruction parsing module is used to parse the target opening degrees of each capillary in the control instruction when the multi - connected air conditioner receives the control instruction;

[0038] The first statistics module is used to sum up the total target powers of each valve controlled to the target opening degree;

[0039] The second statistics module is used to obtain the input power of each valve as the first power and sum up all the first powers to obtain the total actual power;

[0040] The calculation and regulation module is used to judge whether the difference between the total actual power and the total target power is greater than the difference threshold. If the difference is greater than the difference threshold, obtain the bus voltage and regulate the input current based on the bus voltage.

[0041] One of the above technical solutions has the following advantages or beneficial effects: The precise temperature control and stable system operation of the present invention enable users to use the multi-connected air conditioner more conveniently and comfortably, without the need for frequent manual adjustment, greatly improving the user experience and satisfaction. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 is a flowchart of an embodiment of the method of the present invention.

[0043] Figure 2 is a schematic structural diagram of an embodiment of the system of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0044] The following details the embodiments of the present invention. The examples of the embodiments are shown in the drawings, wherein the same or similar reference numerals denote the same or similar elements or elements with the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary only for explaining the present invention and should not be construed as limiting the present invention.

[0045] In the description of the embodiments of the present invention, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the embodiments of the present invention, "a plurality" means two or more unless otherwise specifically defined.

[0046] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise stated, "a plurality" means two or more. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0047] As Figures 1-2 shown, a method for adjusting the input current of a multi-connected air conditioner includes the following steps:

[0048] Step S1: When the multi-connected air conditioner receives a control instruction, parse the target opening degrees of each capillary in the control instruction;

[0049] Step S2: Statistically calculate the total target power for controlling each valve to the target opening degree;

[0050] Step S3: Obtain the input power of each valve as the first power, and statistically calculate all the first powers to obtain the total actual power;

[0051] Step S4: Determine whether the difference between the total actual power and the total target power is greater than the difference threshold. If the difference is greater than the difference threshold, obtain the bus voltage and adjust the input current based on the bus voltage.

[0052] In the actual application scenario of a multi-connected air conditioner, the environments where different indoor units are located are complex and diverse. For example, the room area size, orientation, heat insulation performance, personnel activities, and the external environmental temperature, etc. These factors will all have a significant impact on the cooling / heating effect of the air conditioner. Therefore, under the input current parameters set initially for the multi-connected air conditioner, it may not be able to accurately meet the corresponding target opening degrees of each capillary tube according to the actual needs, thereby resulting in the inability to precisely control the temperatures of each indoor unit, causing deviations in the indoor temperature and affecting the user's comfort experience.

[0053] In the solution proposed by the present invention, when the multi-connected air conditioner receives a control instruction, the system will immediately conduct an in-depth analysis of the control instruction. If the control instruction contains a temperature control command, the system will, based on the linear correspondence relationship established in advance between the temperature control command and the target opening degree of the indoor unit capillary tube, accurately obtain the target opening degrees of the capillary tubes corresponding to each indoor unit by looking up the detailed parameter table of this multi-connected air conditioner product. This precise matching based on product parameters ensures that the setting of the target opening degree conforms to the actual performance characteristics of the multi-connected air conditioner, laying a foundation for subsequent precise control.

[0054] Considering that in the actual use of a multi-connected air conditioner, there may be a situation where multiple indoor units send control instructions simultaneously, the system will comprehensively calculate the total target power required for all valves involved in this control instruction to be adjusted to the target opening degree.

[0055] After the multi-connected air conditioner receives a control instruction and starts to execute the control operation of the corresponding capillary valve, the system obtains the actual input power in real time through the high-precision sensors installed on each valve, and sums up these actual input powers to obtain the total actual power. By accurately judging the difference between the total actual power and the total target power, the system can timely detect possible error situations in the control process.

[0056] If the difference between the total actual power and the total target power is greater than the preset difference threshold, it indicates that the error in this adjustment process exceeds the reasonable control floating range, and there may be unreasonable parameter settings or other potential problems. At this time, the system will quickly obtain the bus voltage and, in combination with the difference between the total actual power and the total target power, precisely adjust the input current. Through this current adjustment method based on real-time data and intelligent algorithms, the system can quickly respond and adjust the operating state of the multi-connected air conditioner, making the capillary opening degrees of each indoor unit closer to the target opening degrees, thereby achieving precise control of the temperature of the multi-connected air conditioner.

[0057] The precise temperature control and stable system operation of the present invention enable users to use the multi-connected air conditioner more conveniently and comfortably, without the need for frequent manual adjustment, greatly improving the user experience and satisfaction.

[0058] Preferably, the specific steps in step S2 are as follows:

[0059] Step S21: Obtain the adjusted opening degree based on the difference between the original valve opening degree and the target opening degree;

[0060] Step S22: Obtain the valve type coefficient, and obtain the motor torque required for this opening degree adjustment through the valve type coefficient and the adjusted opening degree;

[0061] Step S23: Obtain the speed specification of the valve motor, and obtain the target power of the valve through the motor torque and the speed specification;

[0062] Step S24: Statistically calculate the target powers of all valves that need to be adjusted to obtain the total target power.

[0063] Preferably, the calculation formula for the motor torque is as follows:

[0064] T i = K * p * ΔD i * f;

[0065] Where K is the valve type coefficient, p is the pressure when the valve is at the target opening degree, ΔD i is the adjusted opening degree, and f is the friction coefficient;

[0066] The formula for obtaining the target power is as follows:

[0067]

[0068] Where T i is the motor torque of the i-th valve, n is the speed specification, α is the service life coefficient, and β is the constant coefficient for unit conversion of power, torque, and speed.

[0069] Since the input current can no longer effectively control the valve, the method of using voltage and current to obtain the target power can no longer be used. In the present invention, by obtaining the type of the valve, and then through the valve type coefficient and adjusting the opening degree, the torque required for the motor to adjust the valve to the target opening degree is obtained first. For different valves, the values of the valve type coefficients are different. For example, for gate valves, K = 0.15 - 0.3; for ball valves, K = 0.2 - 0.35; for butterfly valves, K = 0.1 - 0.2. The corresponding valve type coefficient can be obtained according to the specific type of each valve and experiments. After knowing the torque, the corresponding target power can be obtained through the rotational speed of the motor. When calculating the target power, the influence brought by the service life needs to be considered. Therefore, in the present invention, a service life coefficient is also added to the calculation of the target power, and the target power is adjusted through the service life coefficient to make the target power conform to the actual operation result.

[0070] Preferably, the bus voltage includes an independent bus voltage and a shared bus voltage;

[0071] When the bus voltage is an independent bus voltage, the weighted average value of the independent bus voltage is obtained to adjust the input current;

[0072] When the bus voltage is a shared bus voltage, the shared bus voltage is used to adjust the input current.

[0073] In the present invention, the regulation of the input current is achieved through the frequency converter module. In the use of the frequency converter, there is a situation where all the frequency converter modules share the same set of DC bus capacitors. At this time, the DC voltages of the frequency converters installed on each indoor unit come from the same bus, so the voltage value is a globally unified value. At this time, only the voltage on any circuit needs to be obtained.

[0074] However, there is also a situation where each frequency converter module has an independent DC bus capacitor, and the DC voltages of each module are isolated from each other, and the voltage values may vary significantly due to different loads. However, since the set input voltage is fixed, the difference in the bus voltage is not large. For the convenience of adjustment and control, when the bus voltage is an independent bus voltage, the weighted average value of the independent bus voltage is taken to adjust the input current. If the average value of the independent bus voltage is directly adopted, the difference in power contribution will be ignored, resulting in errors. By weighting each independent bus voltage and then dividing by the number of independent buses, the weighted average value of the independent bus voltage is obtained. Using the weighted average value of the independent bus voltage to adjust the input current makes the calculation result closer to the actual working condition.

[0075] Preferably, the formula for adjusting the input current based on the bus voltage in step S4 is as follows:

[0076]

[0077] Where P i is the target power, V d is the bus voltage, and k is the adjustment coefficient.

[0078] Preferably, the following steps are further included:

[0079] Step A1: Return the valve to its original position and re-execute the valve control command based on the adjusted current;

[0080] Step A2: Re-obtain the input power of the valve as the second power;

[0081] Step A3: Statistically sum all the second powers to obtain the corrected total actual power;

[0082] Step A4: Obtain the difference between the corrected total actual power and the total target power as the first difference;

[0083] Step A5: If the first difference is greater than the difference threshold, correct the adjustment coefficient through the PI controller and the first difference.

[0084] Preferably, the formula for correcting the adjustment coefficient in Step A5 is as follows:

[0085]

[0086] Where θ is a constant coefficient, K p and K i are the gain coefficients of the PI controller, e is the current first difference, is the average value of the historical first differences, and t is the number of corrections.

[0087] Since in the present invention, the input current is mainly adjusted by the adjustment coefficient k, and the initial value of the adjustment coefficient k is obtained through simulation experiments. However, in actual operation, it will be affected by different factors, resulting in the possibility that the adjusted input current still cannot meet the control requirements. Therefore, in the invention, the adjustment coefficient will also be updated and corrected.

[0088] After the input current is adjusted through step S4, since the input current obtained at this time is the input current required for the valve to be adjusted from the original opening degree to the target opening degree. In order to determine whether the corrected parameters meet the control requirements, it is necessary to return the valve to the original opening degree, then re-execute the control instruction of the valve based on the input current, and then continue to obtain its actual input power in real time through a high-precision sensor as the second power, and count all the second powers to obtain the total actual power after correction; the first difference between the total actual power after correction and the total target power can be used to determine whether the current input current can meet the control requirements. If the first difference is greater than the difference threshold, it means that the adjustment coefficient k at this time still cannot meet the control requirements. At this time, the first difference and the historical data of the first difference will be aligned for correction. By adding the average value of the historical first difference into the PI controller for adjustment, the long-term performance of the system can be evaluated. By using the average value of this historical first difference as the input feature of the PI controller, the PI controller can comprehensively consider the past adjustment situations. The PI controller can sense the change trend of the first difference, so as to adjust the adjustment coefficient k more flexibly.

[0089] A regulating system for the input current of a multi-connected air conditioner, using the above-mentioned method for regulating the input current of a multi-connected air conditioner, includes an instruction parsing module, a first statistics module, a second statistics module, and a calculation and adjustment module;

[0090] The instruction parsing module is used to parse the target opening degree of each capillary in the control instruction when the multi-connected air conditioner receives the control instruction;

[0091] The first statistics module is used to count the total target power of each valve controlled to the target opening degree;

[0092] The second statistics module is used to obtain the input power of each valve as the first power, and count all the first powers to obtain the total actual power;

[0093] The calculation and adjustment module is used to judge whether the difference between the total actual power and the total target power is greater than the difference threshold. If the difference is greater than the difference threshold, the bus voltage is obtained, and the input current is adjusted based on the bus voltage.

[0094] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0095] Although embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the claims and their equivalents.

Claims

1. A method for adjusting input current of a multi-connected air conditioner, characterized in that: The steps include: Step S1: When the multi-split air conditioner receives a control instruction, the target opening and closing degrees of each capillary in the control instruction are analyzed; Step S2: Counting the total target power of each valve controlled to the target opening and closing degree; Step S3: obtaining the input power of each valve as the first power, and counting all the first powers to obtain the total actual power; Step S4: determine whether the difference between the total actual power and the total target power is greater than a difference threshold; if the difference is greater than the difference threshold, obtain the bus voltage and adjust the input current based on the bus voltage.

2. A method for adjusting input current of a multi-connected air conditioner according to claim 1, characterized in that: The specific steps in step S2 are as follows: Step S21: obtaining an adjusted opening degree based on a difference between an original valve opening degree and a target opening degree; Step S22: obtaining a valve type coefficient, and obtaining the motor torque required for the current opening and closing degree adjustment through the valve type coefficient and the adjustment opening and closing degree; Step S23: obtaining the speed specification of the valve motor, and obtaining the target power of the valve through the motor torque and the speed specification; Step S24: Count the target powers of all valves that need to be adjusted to obtain the total target power.

3. A method for adjusting input current of a multi-connected air conditioner according to claim 2, characterized in that: The calculation formula of the motor torque is as follows: T i =K*p*ΔD i *f; Where K is the valve type coefficient, p is the pressure when the valve is at the target opening and closing degree, ΔD i is to adjust the opening and closing degree, f is the friction coefficient; The formula for obtaining the target power is as follows: Where T i is the motor torque of the ith valve, n is the speed specification, α is the age coefficient, and β is the constant coefficient for converting power, torque and speed units.

4. A method for adjusting input current of a multi-connected air conditioner according to claim 3, characterized in that: The bus voltage includes an independent bus voltage and a shared bus voltage; When the bus voltage is an independent bus voltage, a weighted average value of the independent bus voltage is obtained to adjust the input current; When the bus voltage is a shared bus voltage, the shared bus voltage is used to regulate the input current.

5. A method for adjusting input current of a multi-connected air conditioner according to claim 4, characterized in that: The formula for adjusting the input current based on the bus voltage in step S4 is as follows: Where P i is the target power, V d is the bus voltage and k is the regulation coefficient.

6. A method for adjusting input current of a multi-connected air conditioner according to claim 5, characterized in that: Also includes the following steps: Step A1: Return the valve to its original position and re-execute the valve control instruction based on the adjusted current; Step A2: reacquiring the input power of the valve as the second power; Step A3: Count all the second powers to obtain the corrected total actual power; Step A4: obtaining a difference between the corrected total actual power and the total target power as a first difference; Step A5: If the first difference is greater than the difference threshold, the adjustment coefficient is corrected through the PI controller and the first difference.

7. A method for adjusting input current of a multi-connected air conditioner according to claim 6, characterized in that: The formula for correcting the adjustment coefficient in step A5 is as follows: Where θ is a constant coefficient, K p and K i is the gain coefficient of the PI controller, e is the current first difference, is the average of the historical first differences, and t is the number of corrections.

8. A multi-connected air conditioner input current regulation system, characterized in that: A method for adjusting the input current of a multi-split air conditioner according to any one of claims 1 to 7, comprising an instruction parsing module, a first statistical module, a second statistical module and a calculation and adjustment module; The instruction parsing module is used to parse the target opening and closing degree of each capillary in the control instruction when the multi-connected air conditioner receives the control instruction; The first statistical module is used to count the total target power of each valve controlled to a target opening or closing degree; The second statistical module is used to obtain the input power of each valve as the first power, and count all the first powers to obtain the total actual power; The calculation and regulation module is used to determine whether the difference between the total actual power and the total target power is greater than a difference threshold. If the difference is greater than the difference threshold, the bus voltage is obtained and the input current is regulated based on the bus voltage.

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