WO2022048131A1 - Air conditioning system - Google Patents

Abstract

Disclosed is an air conditioning system, comprising a compressor and a frequency converter, and further comprising: a processor module, configured to: respectively acquire the current operating frequency of the compressor and the current torque of the compressor, and calculate the efficiency α₀ of the frequency converter according to the current operating frequency and the current torque.

Description

Air Conditioning System

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority of the Chinese patent application with the application number 202010909922.X and the invention name "Air Conditioning System" filed with the China Patent Office on September 2, 2020, the entire contents of which are incorporated into this application by reference.

technical field

The present application relates to the technical field of household appliances, and in particular, to an air conditioning system with an online power consumption detection function.

Background technique

The basis of the application of intelligent control technology and Internet technology in the air conditioning system is the online real-time monitoring of its performance. Through the analysis of the actual operation performance test data, the deficiencies in the actual operation process of the product are found, the main factors leading to the poor performance of the unit are identified, and the direction for the optimal design of product structure and control strategy is pointed out, and the actual operation of the product can be realized. .

SUMMARY OF THE INVENTION

Embodiments of the present application provide an air conditioning system, including:

compressor;

Inverter

A processor module, which is configured to:

Obtain the current operating frequency of the compressor and the current torque of the compressor respectively;

The efficiency α ₀ of the inverter is calculated according to the current operating frequency and the current torque.

Description of drawings

In order to illustrate the technical solutions of the embodiments of the present application more clearly, the following briefly introduces the drawings used in the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can also be obtained from these drawings without any creative effort.

Figure 1 is a schematic diagram of the power consumption circuit of the air-conditioning system;

FIG. 2 is a schematic block diagram of an air conditioning system provided by some embodiments of the present application;

FIG. 3 is a flowchart of the configuration of a processor module of an air conditioning system provided by some embodiments of the present application;

Fig. 4 is the corresponding relation function curve of the torque of the compressor and the efficiency of the frequency converter fitted when the compressor is operated at 115 Hz according to the embodiment of the present application;

Fig. 5 is the corresponding relation function curve of the torque of the compressor and the efficiency of the frequency converter fitted when the compressor is operated at 110z provided by the embodiment of the present application;

FIG. 6 is a configuration flowchart of a processor module of another air conditioning system provided by an embodiment of the present application.

detailed description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the 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.

In this application, one of the important indicators of online performance monitoring is energy consumption, and the energy consumption of the compressor and its inverter accounts for about 85% of the energy consumption of the entire multi-line system. Therefore, the energy consumption test of the compressor and its inverter Particularly important. In the paper "Online Monitoring Method of Air Conditioning System Performance Based on Limited Measuring Points", Huaiyi Yang et al., in 2018, proposed a calculation scheme based on the application data fitting formula of limited measuring points. As shown in Figure 1, it is a schematic diagram of the electrical circuit. This paper calculates the power consumption of the entire indoor and outdoor units according to the current before point ①. The calculation method is as follows:

In the formula: I _all is the effective current, I' is the current of the outdoor measuring point, I _r is the current of the measuring point, PF is the corresponding power factor, and C ₁ to C ₅ are fitting coefficients.

This method does not distinguish the difference of indoor windshield switching, so the error is large, and the maximum error is 10.3%.

Example 1

The air conditioning system of the present embodiment executes the refrigeration cycle of the air conditioner by controlling the compressor, the condenser, the expansion valve and the evaporator through the processor module. The refrigeration cycle includes a series of processes involving compression, condensation, expansion, and evaporation, and supplies refrigerant to air that has been conditioned and heat-exchanged.

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.

The expansion valve expands the high-temperature and high-pressure liquid-phase refrigerant 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 the cooling effect by using the latent heat of evaporation of the refrigerant to exchange heat with the material to be cooled. Throughout the cycle, the air conditioner regulates the temperature of the indoor space.

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 may be provided in the indoor unit or the outdoor unit.

Indoor heat exchangers and outdoor heat exchangers are used as condensers or evaporators. When the indoor heat exchanger is used as a condenser, the air conditioner is used as a heater in a heating mode, and when the indoor heat exchanger is used as an evaporator, the air conditioner is used as a cooler in a cooling mode.

The air conditioning system of this embodiment, as shown in FIG. 2 , 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 an optimal rotational speed state, thereby saving the energy consumption of the air conditioner .

With the application of intelligent control technology and Internet technology in air-conditioning systems, the basis is the ability to monitor the performance of air-conditioning systems in real time online. Through the analysis of the actual operation performance test data, the deficiencies in the actual operation process of the product are found, the main factors leading to the poor performance of the unit are identified, and the direction for the optimal design of product structure and control strategy is pointed out, and the actual operation of the product can be realized. .

In addition, with the increasing awareness of energy conservation and environmental protection of air conditioners and the continuous improvement of home intelligence, the concept of intelligent air conditioners has become more popular. In terms of air-conditioning temperature setting, when the indoor temperature is within a certain range, there is almost no difference in the comfort of the human body. If the temperature is set to a lower or higher temperature within this range, the comfort of the human body does not change, but increases the performance of the air-conditioning. It is not conducive to reminding the energy consumption of the air conditioner corresponding to the temperature set by the user, it is not conducive to the long-term use of the air conditioner, and it is not conducive to environmental protection and energy saving. Therefore, there is an urgent need for on-line monitoring of energy consumption of air-conditioning systems.

The processor module in this embodiment is configured as:

Obtain the current operating frequency of the compressor and the current torque of the compressor respectively;

Calculate the efficiency α ₀ of the frequency converter according to the current operating frequency and the current torque.

In the air-conditioning system of this embodiment, the efficiency of the inverter is calculated according to the torque of the compressor and the operating frequency. The operating frequency is a control output parameter, which is easy to obtain. There is no need to set up additional detection devices, which simplifies the test complexity. The external detection device introduces test error, which improves the detection accuracy of the frequency converter's efficiency.

After the efficiency α ₀ of the inverter is obtained, the input power _Pr of the inverter can be calculated according to the efficiency α ₀ of the inverter.

The input power P _r of the inverter can be obtained by calculating the active power or by calculating the apparent power;

Wherein, as shown in FIG. 3 , in this embodiment, the calculation of the input power P _r of the inverter by using the active power is taken as an example for description, including:

Obtain the output active power P _c of the inverter;

Calculate the input power P _r of the inverter: P _r =P _c /α ₀ .

The input power _Pr of the frequency converter is the energy consumption of the compressor and its frequency converter.

The torque of the compressor is related to the discharge temperature, discharge 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.

Before obtaining the efficiency of the inverter, first obtain the efficiency curve of the inverter in the laboratory, that is, the corresponding relationship function between the torque of the compressor and the efficiency of the inverter.

The method for obtaining the efficiency α ₀ of the frequency converter in this embodiment is:

The compressor is controlled to run at different operating frequencies, and the corresponding relationship functions between the torque of the compressor and the efficiency of the inverter when running at each operating frequency are respectively fitted.

In this embodiment, a limited number of operating frequencies are selected, and a 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, among the selected limited number of operating frequencies, each operating frequency corresponds to a corresponding function between the torque of the compressor and the efficiency of the frequency converter.

The efficiency of the inverter at different torques and frequencies is experimentally measured, and the formula is fitted. Because the stator and rotor tooling test uses water cooling and air cooling for the inverter at the same time, the test efficiency will be higher than the actual efficiency, and the laboratory experiment will be checked later.

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

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

Input the current torque of the compressor into f ₀ (n) to obtain the efficiency α ₀ of the inverter.

If the current operating frequency just corresponds to the corresponding function f ₀ (n) of the fitted torque of the compressor and the efficiency of the inverter, after obtaining the torque of the compressor, bring it into the function f ₀ (n) Obtain the efficiency α ₀ of the inverter under this operating frequency and this torque.

Since the number of operating frequencies of the compressor fitted with the corresponding function between the torque of the compressor and the efficiency of the inverter is discrete and limited, if the current operating frequency of the compressor does not correspond to the torque of the compressor and the efficiency of the inverter The corresponding relationship function is to find out the corresponding relationship functions f ₁ (n) and f ₂ (n) between the torque of the two compressors adjacent to the current operating frequency and the efficiency of the inverter.

That is, although the current operating frequency of the compressor does not correspond to the corresponding function between the torque of the compressor and the efficiency of the inverter, if the current operating frequency of the compressor is not located at both ends of the value, it must have two adjacent operating frequencies. frequencies n1 and n2, and the two operating frequencies are respectively fitted with the corresponding relationship functions f ₁ (n) and f ₂ (n) of the torque of the compressor and the efficiency of the inverter. If the current operating frequency of the compressor is at both ends of the value, it has an adjacent operating frequency, and the operating frequency is fitted with a function f ₁ (n) corresponding to the torque of the compressor and the efficiency of the inverter. At the same time, the operation frequency adjacent to the current operation frequency is taken, and the operation frequency is also fitted with the corresponding relationship function between the torque of the compressor and the efficiency of the inverter, which is denoted as f ₂ (n).

Input the current torque of the compressor into f ₁ (n) and f ₂ (n) respectively to obtain the efficiencies α ₁ and α ₂ of the inverter;

The interpolation calculation α ₀ includes: calculating the efficiency α ₀ of the frequency converter corresponding to the current operating frequency by using the interpolation method according to α ₁ and α ₂ .

In order to simplify the calculation and reduce the amount of calculation, because the difference between n1 and n2 is small, that is, the operating frequency does not change much, and when the torque is the same, the change of the efficiency of the inverter can be equivalent to a linear change. That is, in the step of calculating α ₀ by interpolation, the efficiency α ₀ of the frequency converter corresponding to the current operating frequency is calculated according to α ₁ and α ₂ by using a linear interpolation method.

The fitting method of the correspondence function between the torque of the compressor and the efficiency of the inverter is:

Control the compressor to keep running at the set operating frequency;

By calculating the torque of the compressor at different times and measuring the efficiency of the corresponding inverter, several sets of torque-efficiency data can be obtained;

According to the torque of the compressor and the efficiency of the corresponding frequency converter at different times, the corresponding relationship function of the two when running at the set running frequency is fitted.

As shown in Table 1 and Table 2, among them, Table 1 is the torque-efficiency correspondence table when the operating frequency is 115hz, and Table 2 is the torque-efficiency correspondence table when the operating frequency is 110hz.

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

Table 1

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

Table 2

The corresponding function curve of the torque of the compressor and the efficiency of the inverter fitted according to Table 1 is shown in Figure 4, and the corresponding function curve of the torque of the compressor and the efficiency of the inverter fitted according to Table 2 is shown in Figure 5 Show.

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

Taking 450 cooling machine as an example, when the torque is 16.28N m, the operating frequency of the compressor is 112Hz, and the output power of the inverter is 11950W, the calculation method of the input power of the inverter is as follows:

Since the operating frequency of 112 Hz does not correspond to the corresponding function between the torque of the compressor and the efficiency of the inverter, the calculation is performed according to the functions of two operating frequencies adjacent to 112 Hz, 115 Hz and 110 Hz.

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

=0.9320+0.002420*16.28-0.000113 115*16.28^2=0.9414

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

=0.9463+0.000504*16.28-0.000040*16.28^2=0.9439

f ₁ (n115) is the efficiency of the inverter whose operating frequency is 115Hz; f ₂ (n110) is the efficiency of the inverter whose operating frequency is 110 Hz.

n115 is the torque of the compressor whose operating frequency is 115 Hz; n110 is the torque of the compressor whose operating frequency is 110 Hz.

The value between the two collection points can be obtained by interpolation, which satisfies the following relationship:

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

It can be concluded that α ₀ =(2*0.9414+3*0.9439)/5=0.9429;

Therefore, the input power of the inverter is calculated as 11950/0.9429*α=12673.7*αW

There is a deviation of about 5% between the input power of the inverter and the actual power obtained by measurement and calculation, which is greatly improved compared with the accuracy of the existing algorithm.

In a possible implementation, the calculation method of the torque of the compressor is:

Obtain the outlet enthalpy value h ₁ and the inlet enthalpy value h ₂ of the compressor respectively;

Obtain the density ρ of the refrigerant sucked by the compressor and the rotational speed Rpm of the compressor;

Torque of compressor=a*(h ₁ -h ₂ )*ρ*Rpm*η/b/Rpm;

Among them, η is the volumetric efficiency of the compressor, which is a fixed value, and a and b are fitting parameters.

The outlet enthalpy value h ₁ is calculated from the discharge temperature and discharge pressure of the compressor, and the enthalpy value h ₂ is calculated from the suction temperature and suction pressure of the compressor.

During the fitting process of the corresponding relationship function between the torque of the compressor and the efficiency of the inverter, the difference between the two adjacent set operating frequencies is Δf. Efficiency correspondence function.

The method of outputting active power P _c of the inverter is:

Collect the output current I of the inverter, and obtain the output voltage U of the inverter;

Calculate P _c =I·U·F _2i ;

Among them, F _2i is the output power factor of the inverter, which can be obtained directly from the inverter.

The circuit board of the inverter contains a current sensor, which can collect the output current I of the inverter, and the output voltage U is the output control value, which can be obtained directly.

Another calculation method of the efficiency α ₀ of the frequency converter is:

Get the current operating frequency f of the compressor;

The efficiency α ₀ of the frequency converter is calculated according to the current operating frequency f of the compressor and the current torque n of the compressor.

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

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

In this scheme, the efficiency α ₀ of the frequency converter is fitted to the surface of the two factors of frequency and torque, which makes the calculation more concise.

Embodiment 2

The air conditioning system of this embodiment can also calculate the input power of the inverter by outputting the apparent power S _2i . As shown in FIG. 6 , the processor module of this embodiment is configured as:

Obtain the current operating frequency of the compressor and the current torque of the compressor respectively;

Calculate the efficiency α ₀ of the inverter according to the current operating frequency and the current torque;

Obtain the apparent power S _2i of the output side of the inverter;

Obtain the output side power factor F _2i of the inverter;

Calculate the input power P _r of the inverter:

P _r =S _2i *F _2i /α ₀ .

S _2i is calculated and output by the frequency converter, and α ₀ can be obtained by the solution described in the first embodiment, which will not be repeated here. F _2i is the output power factor of the inverter, which can be obtained directly from the inverter.

In the air-conditioning system of this embodiment, the efficiency of the inverter is calculated according to the torque of the compressor and the operating frequency. The operating frequency is a control output parameter, which is easy to obtain. The output power factor of the inverter can be directly obtained from the inverter without additional settings. The detection device simplifies the test complexity, and at the same time does not introduce test errors due to external detection devices, thus improving the efficiency and detection accuracy of the frequency converter.

This embodiment solves the technical problems that the on-line energy consumption monitoring of the compressor frequency converter needs to set multiple measurement points to collect parameters, resulting in the use of many test devices, complex test solutions, and the introduction of many errors, resulting in low accuracy. The air conditioning system of the present application , which calculates the efficiency of the inverter according to the torque and operating frequency of the compressor, without the need to set up external test devices, which simplifies the test complexity and improves the detection accuracy of the inverter's efficiency.

The above are only specific embodiments of the present application, but the protection scope of the present 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 the present application shall be covered. within the scope of protection of this application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims (14)

1. An air-conditioning system, comprising a compressor and a frequency converter, is characterized in that, further comprising:

   A processor module, which is configured to:

   Obtain the current operating frequency of the compressor and the current torque of the compressor respectively;

   The efficiency α ₀ of the inverter is calculated according to the current operating frequency and the current torque.
2. The air-conditioning system according to claim 1, wherein the method for obtaining the efficiency α0 of the frequency converter is _:

   Control the compressor to run at different operating frequencies, and respectively fit the corresponding function between the torque of the compressor and the efficiency of the inverter when running at each operating frequency;

   Find the corresponding relationship function f ₀ (n) between the torque of the compressor corresponding to the current operating frequency and the efficiency of the inverter, where n represents the torque of the compressor;

   Input the current torque of the compressor into f ₀ (n) to obtain the efficiency α ₀ of the inverter;

   or,

   Get the current operating frequency of the compressor;

   The efficiency α ₀ of the inverter is calculated according to the current operating frequency of the compressor and the current torque of the compressor.
3. The air-conditioning system according to claim 2, wherein if the current operating frequency does not correspond to a corresponding function between the torque of the compressor and the efficiency of the frequency converter, then find out two adjacent to the current operating frequency. Corresponding relationship functions f ₁ (n) and f ₂ (n) between the torque of the compressor and the efficiency of the inverter;

   Input the current torque of the compressor into f ₁ (n) and f ₂ (n) respectively to obtain the efficiencies α ₁ and α ₂ of the inverter;

   The interpolation calculation α ₀ includes: calculating the efficiency α ₀ of the frequency converter corresponding to the current operating frequency by using the interpolation method according to α ₁ and α ₂ .
4. The air conditioning system according to claim 3, characterized in that, in the step of calculating α ₀ by interpolation, the efficiency α ₀ of the frequency converter corresponding to the current operating frequency is calculated according to α ₁ and α ₂ by linear interpolation.
5. The air-conditioning system according to claim 2, wherein the fitting method of the corresponding relationship function between the torque of the compressor and the efficiency of the frequency converter is:

   Control the compressor to keep running at the set operating frequency;

   Calculate the torque of the compressor at different times and measure the efficiency of the corresponding inverter;

   According to the torque of the compressor and the efficiency of the corresponding frequency converter at different times, the corresponding relationship function of the two when running at the set running frequency is fitted.
6. The air-conditioning system according to claim 5, wherein the calculation method of the torque of the compressor is:

   Obtain the outlet enthalpy value h ₁ and the inlet enthalpy value h ₂ of the compressor respectively;

   Obtain the density ρ of the refrigerant sucked by the compressor and the rotational speed Rpm of the compressor;

   Torque of compressor=a*(h ₁ -h ₂ )*ρ*Rpm*η/b/Rpm;

   Among them, η is the volumetric efficiency of the compressor, which is a fixed value, and a and b are fitting parameters.
7. The air conditioning system according to claim ₆ , wherein the outlet enthalpy value _h1 is calculated and obtained according to the discharge temperature and discharge pressure of the compressor, and the inlet enthalpy value h2 is obtained according to the suction temperature and the discharge pressure of the compressor. Inspiratory pressure is calculated.
8. The air-conditioning system according to claim 5, wherein in 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.
9. The air-conditioning system according to claim 2, wherein the corresponding function between the torque of the compressor and the efficiency of the inverter is a quadratic function.
10. The air-conditioning system according to any one of claims 1-9, characterized in that,

    Calculate the input power _Pr of the frequency converter according to the efficiency α ₀ of the frequency converter;
11. The air conditioning system of claim 10, wherein:

    The input power Pr of the inverter is calculated from the active power or the input power _Pr of the inverter is calculated from the _apparent power.
12. The air conditioning system of claim 11, wherein:

    Among them, calculating the input power P _r of the inverter through the active power includes:

    Obtain the output active power P _c of the inverter;

    Calculate the input power P _r of the inverter: P _r =P _c /α ₀ .
13. The air conditioning system of claim 11, wherein:

    Calculating the input power P _r of the inverter through the apparent power includes:

    Obtain the output apparent power S _2i of the inverter;

    Obtain the output power factor F _2i of the inverter;

    Calculate the input power P _r of the inverter:

    P _r =S _2i *F _2i /α ₀
14. The air conditioning system of claim 12, wherein:

    The method of outputting active power P _c of the inverter is:

    Collect the output current I of the inverter, and obtain the output voltage U of the inverter;

    Calculate P _c =I·U·F _2i ;

    Among them, F _2i is the output power factor of the frequency converter.

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