Air conditioning system

Abstract

The present application discloses an air conditioning system, including a compressor and an inverter, further including: a processor module configured to: respectively obtain the current operating frequency of the compressor and the current torque of the compressor; calculate the efficiency of the inverter according to the current operating frequency and the current torque.

Description

[0001] Cross - reference to related applications

[0002] This application claims the priority of a Chinese patent application filed with the Chinese Patent Office on September 2, 2020, with the application number 202010909922.X and the invention title "Air Conditioning System", the entire content of which is incorporated herein by reference. Technical Field

[0003] This application relates to the technical field of household appliances, and particularly to an air conditioning system with an online power consumption detection function. Background Art

[0004] The basis for the application of intelligent control technology and Internet technology in an air conditioning system is the ability to perform online real-time monitoring of its performance. By analyzing the actual operation performance test data, the deficiencies existing in the product during actual operation can be found, the main factors leading to poor unit performance can be identified, which points the way for the optimized design of the product structure and control strategy, and realizes energy conservation during the actual operation of the product. Summary of the Invention

[0005] An embodiment of this application provides an air conditioning system, including:

[0006] A compressor;

[0007] An inverter

[0008] A processor module, which is configured to:

[0009] Obtain the current operating frequency and the current torque of the compressor respectively;

[0010] Calculate the efficiency α of the inverter according to the current operating frequency and the current torque 0 . Brief Description of the Drawings

[0011] In order to more clearly illustrate the technical solutions of the embodiments of this application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of this application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0012] Figure 1 It is a schematic diagram of the power consumption circuit of the air conditioning system;

[0013] Figure 2 It is a schematic block diagram of the principle of the air conditioning system provided by some embodiments of this application;

[0014] Figure 3 It is a flowchart of the configuration of the processor module of the air conditioning system provided by some embodiments of this application;

[0015] Figure 4 is the function curve of the corresponding relationship between the torque of the compressor and the efficiency of the frequency converter fitted when the compressor provided by the embodiment of the present application operates at 115 Hz;

[0016] Figure 5 is the function curve of the corresponding relationship between the torque of the compressor and the efficiency of the frequency converter fitted when the compressor provided by the embodiment of the present application operates at 110 Hz;

[0017] Figure 6 is the configuration flow chart of the processor module of another air conditioning system provided by the embodiment of the present application. Detailed implementation manners

[0018] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0019] In the present application, one of the important indicators of on-line performance monitoring is energy consumption, and the energy consumption of the compressor and its frequency converter accounts for about 85% of the energy consumption of the entire multi-connected air conditioner system. Therefore, the energy consumption test of the compressor and its frequency converter is particularly important. The paper "On-line Performance Monitoring Method of Air Conditioning System Based on Limited Measuring Points", Yang Huaiyi et al., proposed a calculation scheme based on the application of data fitting formula with limited measuring points in 2018. As Figure 1 shown, it is a schematic diagram of the electric circuit. According to the current before point ①, the power consumption of the entire indoor and outdoor units is calculated, and the calculation method is as follows:

[0020]

[0021] In the formula: I all is the effective current, I' is the current at the outdoor measuring point, I r is the measuring point current, PF is the corresponding power factor, C 1 ~C 5 are all fitting coefficients.

[0022] This method does not distinguish the difference in indoor air volume adjustment, so the error is relatively large, and the maximum error is 10.3%.

[0023] Embodiment 1

[0024] The air conditioning system in this embodiment controls the compressor, condenser, expansion valve and evaporator through the processor module to execute the refrigeration cycle of the air conditioner. The refrigeration cycle includes a series of processes, involving compression, condensation, expansion and evaporation, and supplies refrigerant to the air that has been conditioned and heat-exchanged.

[0025] The compressor compresses the refrigerant gas in a high-temperature and high-pressure state and discharges the compressed refrigerant gas. The discharged refrigerant gas flows into the condenser. The condenser condenses the compressed refrigerant into a liquid phase, and heat is released to the surrounding environment through the condensation process.

[0026] The expansion valve expands the liquid-phase refrigerant in a high-temperature and high-pressure state condensed in the condenser into a low-pressure liquid-phase refrigerant. The evaporator evaporates the refrigerant expanded in the expansion valve and returns the refrigerant gas in a low-temperature and low-pressure state to the compressor. The evaporator can achieve a refrigeration effect by using the latent heat of evaporation of the refrigerant for heat exchange with the material to be cooled. Throughout the cycle, the air conditioner can adjust the temperature of the indoor space.

[0027] The outdoor unit of the air conditioner refers to the part of the refrigeration cycle including the compressor and the outdoor heat exchanger. The indoor unit of the air conditioner includes the indoor heat exchanger, and the expansion valve can be provided in the indoor unit or the outdoor unit.

[0028] The indoor heat exchanger and the outdoor heat exchanger serve as condensers or evaporators. When the indoor heat exchanger serves as a condenser, the air conditioner serves as a heater in the heating mode. When the indoor heat exchanger serves as an evaporator, the air conditioner serves as a cooler in the cooling mode.

[0029] The air-conditioning system of this embodiment, as Figure 2 shown, further includes a frequency converter, which controls and adjusts the rotational speed of the compressor in the air conditioner, so that the compressor is always in the best rotational speed state, thereby saving the energy consumption of the air conditioner.

[0030] With the application of intelligent control technology and Internet technology in the air-conditioning system, its basis is the ability to online real-time monitor the performance of the air-conditioning system. Through the analysis of the actual operation performance test data, the deficiencies existing in the actual operation process of the product are found, the main factors leading to poor unit performance are explored, which points the way for the optimized design of the product structure and the control strategy, and realizes the energy saving of the actual operation of the product.

[0031] In addition, with the increasing awareness of energy conservation and environmental protection in air conditioners and the continuous improvement of home intelligence, the concept of intelligent air conditioners is more popular. In terms of air-conditioning temperature setting, when the indoor temperature is within a certain range, there is almost no difference in human comfort. If the temperature is set lower or higher within this range, the human comfort does not change, but the energy consumption of the air conditioner increases, which is not conducive to reminding the user of the energy consumption of the air conditioner corresponding to the set temperature, not conducive to the long-term use of the air conditioner, and not conducive to environmental protection and energy conservation. Therefore, the demand for online monitoring of the energy consumption of the air-conditioning system is very urgent.

[0032] The processor module in this embodiment is configured to:

[0033] Obtain the current operating frequency of the compressor and the current torque of the compressor respectively;

[0034] Calculate the efficiency α of the frequency converter according to the current operating frequency and the current torque 0 ;.

[0035] In the air-conditioning system of this embodiment, the efficiency of the frequency converter is calculated based on the torque and operating frequency of the compressor. The operating frequency is a control output parameter and is easy to obtain without additional detection devices, which simplifies the test complexity. At the same time, test errors are not introduced due to external detection devices, improving the detection accuracy of the efficiency of the frequency converter.

[0036] Obtain the efficiency α of the frequency converter 0 After that, the input power P of the frequency converter can be calculated according to the efficiency α of the frequency converter 0 Calculate the input power P of the frequency converter r .

[0037] The input power P of the frequency converter r can be obtained by calculating the active power or by calculating the apparent power;

[0038] Among them, as Figure 3 shown, in this embodiment, the input power P of the frequency converter is calculated by the active power as an example, including: r For example, it is described as follows:

[0039] Obtain the output active power P of the frequency converter c ;

[0040] Calculate the input power P of the frequency converter r ∶P r =P c / α 0 .

[0041] The input power P of the frequency converter r is also the energy consumption of the compressor and its frequency converter.

[0042] The torque of the compressor is related to the exhaust temperature, exhaust pressure, suction temperature and suction pressure of the compressor, and the above parameters can be obtained through the air-conditioning system without additional detection devices.

[0043] Before obtaining the efficiency of the frequency converter, first obtain the efficiency curve of the frequency converter in the laboratory, that is, the corresponding relationship function between the torque of the compressor and the efficiency of the frequency converter.

[0044] In this embodiment, the method for obtaining the efficiency α of the frequency converter is: 0 as follows:

[0045] Control the compressor to operate at different operating frequencies, and respectively fit the corresponding relationship function between the torque of the compressor and the efficiency of the frequency converter when operating at each operating frequency.

[0046] In this embodiment, a limited number of operating frequencies are selected, and the corresponding relationship function between the torque of the compressor and the efficiency of the frequency converter when operating at each operating frequency is fitted in the laboratory. Therefore, for each of the limited number of operating frequencies selected, there is a corresponding relationship function between the torque of the compressor and the efficiency of the frequency converter.

[0047] The efficiency of the frequency converter at different torques and different frequencies is experimentally measured and a formula is fitted. Because of the stator-rotor tooling test, while using water cooling and air cooling for heat dissipation of the frequency converter, the measured efficiency will be higher than the actual efficiency, and it will be rechecked in later laboratory experiments.

[0048] Find the corresponding relationship function f 0 (n) between the torque of the compressor and the efficiency of the frequency converter corresponding to the current operating frequency, where n represents the torque of the compressor.

[0049] The current operating frequency can be directly obtained through the system.

[0050] Input the current torque of the compressor into f 0 (n) to obtain the efficiency α of the frequency converter. 0 .

[0051] If the current operating frequency exactly corresponds to the fitted corresponding relationship function f 0 (n) between the torque of the compressor and the efficiency of the frequency converter, after obtaining the torque of the compressor, substitute it into the function f 0 (n) to obtain the efficiency α of the frequency converter at this operating frequency and this torque. 0 .

[0052] Since the number of operating frequencies of the compressor for which the corresponding relationship function between the torque of the compressor and the efficiency of the frequency converter is fitted is discrete and finite, if the current operating frequency of the compressor does not correspond to the corresponding relationship function between the torque of the compressor and the efficiency of the frequency converter, then find the two corresponding relationship functions f 1 (n) and f 2 (n) between the torque of the compressor and the efficiency of the frequency converter that are adjacent to the current operating frequency.

[0053] That is, although the current operating frequency of the compressor does not correspond to the corresponding relationship function between the torque of the compressor and the efficiency of the frequency converter, if the current operating frequency of the compressor is not at both ends of the value, it must have two adjacent operating frequencies n1 and n2, and the two operating frequencies are respectively fitted with the corresponding relationship functions f 1 (n) and f 2(n). If the current operating frequency of the compressor is at either end of the numerical value, it has an adjacent operating frequency, and this operating frequency fits the corresponding relationship function f between the torque of the compressor and the efficiency of the frequency converter 1 (n). At the same time, take the operating frequency that is the second adjacent to the current operating frequency, and this operating frequency also fits the corresponding relationship function between the torque of the compressor and the efficiency of the frequency converter, denoted as f 2 (n).

[0054] Input the current torque of the compressor into f 1 (n) and f 2 (n), and obtain the efficiency α of the frequency converter 1 and α 2 ;

[0055] Interpolate to calculate α 0 , including: Calculate the efficiency α of the frequency converter corresponding to the current operating frequency by interpolation method according to α 1 and α 2 0 .

[0056] To simplify the calculation and reduce the amount of calculation, since the difference between n1 and n2 is small, that is, the change in the operating frequency is not large, when the torque is the same, the change in the efficiency of the frequency converter can be equivalent to a linear change. That is, in the step of interpolating to calculate α 0 , according to α 1 and α 2 Calculate the efficiency α of the frequency converter corresponding to the current operating frequency by linear interpolation method 0 .

[0057] The fitting method of the corresponding relationship function between the torque of the compressor and the efficiency of the frequency converter is:

[0058] Control the compressor to run at the set operating frequency;

[0059] Calculate the torque of the compressor at different times and measure the corresponding efficiency of the frequency converter, and several groups of torque-efficiency data can be obtained;

[0060] According to the torque of the compressor at different times and its corresponding efficiency of the frequency converter, fit the corresponding relationship function between the two when running at the set operating frequency.

[0061] As shown in Table 1 and Table 2, where Table 1 is the torque-efficiency correspondence table when the operating frequency is 115 hz, and Table 2 is the torque-efficiency correspondence table when the operating frequency is 110 hz.

[0062] 115 Torque (N.m) 17.5 16.34 15.48 14.48 13.68 12.68 11.81 10.94 9.81 8.81 115 Efficiency 0.9402 0.9409 0.9422 0.9435 0.9444 0.9444 0.9448 0.9452 0.94441 0.94471

[0063] Table 1

[0064] 110 Torque (N.m) 17.6 16.66 15.67 14.6 13.66 12.74 11.67 10.77 9.64 8.58 110 Efficiency 0.9422 0.9434 0.9439 0.9455 0.9463 0.9461 0.9462 0.9471 0.94755 0.94759

[0065] Table 2

[0066] The corresponding relationship function curve between the torque of the compressor and the efficiency of the frequency converter fitted according to Table 1 is as Figure 4 shown, and the corresponding relationship function curve between the torque of the compressor and the efficiency of the frequency converter fitted according to Table 2 is as Figure 5 shown.

[0067] In this embodiment, the corresponding relationship function between the torque of the compressor and the efficiency of the frequency converter is a quadratic function.

[0068] Taking the refrigeration of 450 as an example, when the torque is 16.28 N·m, the operating frequency of the compressor is 112 Hz, and the output power of the frequency converter is 11950 W, the calculation method of the input power of the frequency converter is as follows:

[0069] Since there is no corresponding relationship function between the torque of the compressor and the efficiency of the frequency converter for the operating frequency of 112 Hz, the functions of the two adjacent operating frequencies of 115 Hz and 110 Hz are used for calculation.

[0070] f 1 (n115) = 0.9320 + 0.002420 * n115 - 0.000113 * n115^2 (the formula is obtained by fitting Table 1)

[0071] = 0.9320 + 0.002420 * 16.28 - 0.000113115 * 16.28^2 = 0.9414

[0072] f 2 (n110) = 0.9463 + 0.000504 * n110 - 0.000040 * n110^2 (the formula is obtained by fitting Table 2)

[0073] = 0.9463 + 0.000504 * 16.28 - 0.000040 * 16.28^2 = 0.9439

[0074] f 1 (n115) is the efficiency of the frequency converter with an operating frequency of 115 Hz; f 2 (n110) is the efficiency of the frequency converter with an operating frequency of 110 Hz.

[0075] n115 is the torque of the compressor with an operating frequency of 115 Hz; n110 is the torque of the compressor with an operating frequency of 110 Hz.

[0076] The value between two acquisition points can be obtained by interpolation method and satisfies the following relationship:

[0077] (f 1 (n115)-α 0 ) / (α 0 -f 2 (n110))=(115 - 112) / (112 - 110)

[0078] It can be obtained that α 0 =(2 * 0.9414 + 3 * 0.9439) / 5 = 0.9429;

[0079] Therefore, the input power of the frequency converter is estimated to be 11950 / 0.9429 * α =12673.7 * α W

[0080] The deviation between the input power of the frequency converter obtained through measurement and calculation and the actual power is about 5%, which is greatly improved compared with the accuracy of the existing algorithm.

[0081] In a possible implementation manner, the calculation method of the torque of the compressor is as follows:

[0082] Obtain the outlet enthalpy value h 1 and the inlet enthalpy value h 2 ;

[0083] Obtain the density ρ of the refrigerant inhaled by the compressor and the rotational speed Rpm of the compressor;

[0084] The torque of the compressor = a * (h 1 -h 2 ) * ρ * Rpm * η / b / Rpm;

[0085] Wherein, η is the volumetric efficiency of the compressor, which is a fixed value, and a and b are fitting parameters.

[0086] The outlet enthalpy value h 1 is calculated according to the discharge temperature and discharge pressure of the compressor, and the enthalpy value h 2 is calculated according to the suction temperature and suction pressure of the compressor.

[0087] During the fitting process of the corresponding relationship function between the torque of the compressor and the efficiency of the frequency converter, the difference between two adjacent set operating frequencies is Δf, for example, a corresponding relationship function between the torque of the compressor and the efficiency of the frequency converter is fitted every 5 Hz.

[0088] The method for the active power P c output by the frequency converter is as follows:

[0089] Collect the output current I of the frequency converter and obtain the output voltage U of the frequency converter;

[0090] Calculate P c =I·U·F2i ;

[0091] Among them, F 2i is the output power factor of the frequency converter and can be directly obtained from the frequency converter.

[0092] The circuit board of the frequency converter contains a current sensor, which can collect the output current I of the frequency converter. The output voltage U is the output control quantity and can be directly obtained.

[0093] The efficiency α of the frequency converter 0 Another calculation method is:

[0094] Obtain the current operating frequency f of the compressor;

[0095] Calculate the efficiency α of the frequency converter according to the current operating frequency f of the compressor and the current torque n of the compressor 0 .

[0096] In a possible implementation, α 0 = a1*f + b1*n + c1*f*n + d1*f^2 + e1*n^2.

[0097] Among them, a1, b1, c1, d1, and e1 are constants and can be set according to the actual situation.

[0098] In this solution, by fitting the efficiency α of the frequency converter 0 into a surface of two factors, frequency and torque, the calculation becomes more concise.

[0099] Embodiment 2

[0100] The air-conditioning system of this embodiment can also calculate the input power of the frequency converter by outputting the apparent power S 2i . As shown in Figure 6 , the processor module of this embodiment is configured to:

[0101] Respectively obtain the current operating frequency of the compressor and the current torque of the compressor;

[0102] Calculate the efficiency α of the frequency converter according to the current operating frequency and the current torque 0 ;

[0103] Obtain the apparent power S on the output side of the frequency converter 2i ;

[0104] Obtain the power factor F on the output side of the frequency converter 2i ;

[0105] Calculate the input power P of the frequency converter r :

[0106] P r = S2i *F 2i / α 0 。

[0107] S 2i Calculated and output by the frequency converter, α 0 can be obtained by the solution described in Embodiment 1 and will not be elaborated here. F 2i is the output power factor of the frequency converter and can be directly obtained from the frequency converter.

[0108] For the air-conditioning system of this embodiment, its efficiency of the frequency converter is calculated based on the torque and operating frequency of the compressor. The operating frequency is a control output parameter and is easily obtained. The output power factor of the frequency converter can be directly obtained from the frequency converter without additionally setting detection devices, simplifying the complexity of the test. At the same time, test errors are not introduced due to external detection devices, improving the detection accuracy of the efficiency of the frequency converter.

[0109] This embodiment solves the technical problems that online energy consumption monitoring of the compressor frequency converter requires setting multiple measuring points to collect parameters, resulting in a large number of test devices, a complex test scheme, and low accuracy due to more introduced errors. For the air-conditioning system of this application, its efficiency of the frequency converter is calculated based on the torque and operating frequency of the compressor without setting external test devices, simplifying the complexity of the test and improving the detection accuracy of the efficiency of the frequency converter at the same time.

[0110] The above is only the specific implementation manner of this application, but the protection scope of this application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed in this application should be covered by the protection scope of this application. Therefore, the protection scope of this application should be subject to the protection scope of the claims.

Claims

1. An air conditioning system, comprising a compressor and an inverter, Characterized in that, It further comprises: A processor module, which is configured to: Obtain the current operating frequency of the compressor and the current torque of the compressor respectively; Calculate the efficiency α of the frequency converter according to the current operating frequency and the current torque 0 ; Efficiency α of the frequency converter 0 Before obtaining, first obtain the function of the correspondence between the torque of the compressor and the efficiency of the frequency converter; The calculation method of the torque of the compressor is: Obtain the outlet enthalpy value h of the compressor separately 1 and the inlet enthalpy value h 2 ; Obtain the density ρ of the refrigerant sucked by the compressor and the rotational speed Rpm of the compressor; Torque of the compressor = a * (h 1 - h 2 ) * ρ * Rpm * η / b / Rpm; Where η is the volumetric efficiency of the compressor, which is a fixed value, and a and b are fitting parameters; According to the efficiency α of the frequency converter 0 Calculate the input power Pr of the frequency converter; Before obtaining the efficiency of the frequency converter, first obtain the efficiency curve of the frequency converter in the laboratory, that is, the function of the correspondence between the torque of the compressor and the efficiency of the frequency converter; The efficiency α of the frequency converter 0 is obtained by the following method: Control the compressor to operate at different operating frequencies, and respectively fit the corresponding relationship function between the torque of the compressor and the efficiency of the inverter when operating at each operating frequency; Find the corresponding relationship function f between the torque of the compressor corresponding to the current operating frequency and the efficiency of the frequency converter 0 (n), where n represents the torque of the compressor; Input the current torque of the compressor f 0 (n) to obtain the efficiency α of the frequency converter 0 .

2. The air conditioning system according to claim 1, Characterized in that, If there is no corresponding relationship function between the torque of the compressor and the efficiency of the frequency converter for the current operating frequency, then find the two corresponding relationship functions f 1 (n) and f 2 (n); Input the current torque of the compressor into f 1 (n) and f 2 (n) respectively to obtain the efficiency α 1 of the frequency converter and α 2 ; Interpolation calculation of α 0 , including: according to α 1 and α 2 Using the interpolation method to calculate the efficiency α of the frequency converter corresponding to the current operating frequency 0 .

3. The air conditioning system according to claim 2, Characterized in that, Interpolation calculation of α 0 In the step of 1 and α 2 the efficiency α of the frequency converter corresponding to the current operating frequency is calculated by using the linear interpolation method 0 .

4. The air conditioning system according to claim 1, Characterized in that, The fitting method of the corresponding relationship function between the torque of the compressor and the efficiency of the inverter is: Control the compressor to maintain operation at a set operating frequency; Calculate the torque of the compressor at different times and measure the corresponding efficiency of the inverter; According to the torque of the compressor at different times and the corresponding efficiency of the inverter, fit the corresponding relationship function between the two when operating at the set operating frequency.

5. The air conditioning system according to claim 1, Characterized in that, The outlet enthalpy value h 1 is calculated based on the discharge temperature and discharge pressure of the compressor, and the inlet enthalpy value h 2 is calculated based on the suction temperature and suction pressure of the compressor.

6. The air conditioning system according to claim 4, Characterized in that, During the fitting process of the corresponding relationship function between the torque of the compressor and the efficiency of the inverter, the difference between two adjacent set operating frequencies is Δf.

7. The air conditioning system according to claim 1, Characterized in that, The corresponding relationship function between the torque of the compressor and the efficiency of the inverter is a quadratic function.

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