CN113944990A

CN113944990A - Air conditioner and control method

Info

Publication number: CN113944990A
Application number: CN202010679208.6A
Authority: CN
Inventors: 李达君; 尹发展; 由秀玲
Original assignee: Hisense Shandong Air Conditioning Co Ltd
Current assignee: Hisense Shandong Air Conditioning Co Ltd
Priority date: 2020-07-15
Filing date: 2020-07-15
Publication date: 2022-01-18
Anticipated expiration: 2040-07-15
Also published as: CN113944990B

Abstract

The invention discloses an air conditioner and a control method, wherein a controller is configured to acquire the exhaust superheat degree of the air conditioner in the current regulation period and generate a deviation value corresponding to the regulation period according to the exhaust superheat degree and a preset target exhaust superheat degree; determining a variation value between the deviation value corresponding to the adjusting period and the deviation value corresponding to the previous adjusting period; searching a result value corresponding to the deviation value and the change value in a fuzzy control table, wherein the fuzzy control table is generated according to a preset membership function; determining a coefficient according to the ambient temperature of the outdoor side of the air conditioner; generating an adjustment step number according to the result value and the coefficient; the expansion valve is adjusted based on the adjusting step number, so that the air conditioner can adapt to system adjusting requirements under different environmental temperatures and different loads, and the system can reach a balance state by quickly adjusting the expansion valve.

Description

Air conditioner and control method

Technical Field

The present disclosure relates to the field of air conditioner control technologies, and more particularly, to an air conditioner and a control method.

Background

The expansion valve is a key part of the air conditioning system, and the adjusting speed and stability of the expansion valve are related to the stability of the air conditioning system and the cooling and heating effects, so that the comfort of a user is indirectly influenced. When the stability of the system is poor, long-term fluctuation can occur, and the service life of the air conditioner can be further influenced. Therefore, the regulation of the expansion valve is of critical importance in air conditioning systems.

However, in the prior art, because the PID control is currently used in the unit machine system, the PID control mode has slow response speed and is easy to overshoot so as to cause system pressure fluctuation. And when the P, I, D coefficient is determined, the coefficient can not change along with the change of the working environment of the system, and the adaptivity is poor.

Therefore, how to provide a control method with strong adaptability for an air conditioner, which can make the air conditioner adapt to system adjustment requirements under different environmental temperatures and different loads, and can make the system reach a balanced state by quickly adjusting an expansion valve is a technical problem to be solved at present.

Disclosure of Invention

Because the prior art has the problems that the self-adaptability of an expansion valve in the air conditioner is poor and the expansion valve cannot change along with the change of the working environment of the system, the invention provides an air conditioner, which comprises:

the refrigerant circulation loop circulates the refrigerant in a loop formed by the compressor, the condenser, the expansion valve, the evaporator, the four-way valve and the pressure reducer;

the compressor is used for compressing low-temperature and low-pressure refrigerant gas into high-temperature and high-pressure refrigerant gas and discharging the high-temperature and high-pressure refrigerant gas to the condenser;

one of the outdoor heat exchanger and the indoor heat exchanger works for the condenser, and the other works for the evaporator;

the indoor coil temperature sensor is used for detecting the temperature of the indoor coil;

the outdoor coil temperature sensor is used for detecting the temperature of the outdoor coil;

an outdoor environment temperature sensor for detecting an outdoor environment temperature;

the four-way valve is used for controlling the flow direction of the refrigerant in the refrigerant loop so as to switch the outdoor heat exchanger and the indoor heat exchanger between the condenser and the evaporator;

an exhaust temperature sensor for detecting an exhaust temperature;

in some embodiments, the controller is configured to:

acquiring the exhaust superheat degree of the air conditioner in the current regulation period, and generating a deviation value corresponding to the regulation period according to the exhaust superheat degree and a preset target exhaust superheat degree;

determining a variation value between the deviation value corresponding to the adjusting period and the deviation value corresponding to the previous adjusting period;

searching a result value corresponding to the deviation value and the change value in a fuzzy control table, wherein the fuzzy control table is generated according to a preset membership function;

determining a coefficient according to the ambient temperature of the outdoor side of the air conditioner;

generating an adjustment step number according to the result value and the coefficient;

adjusting the expansion valve based on the adjustment steps.

In some embodiments, the membership function comprises at least:

the air conditioner comprises a maximum positive value and a minimum negative value of an allowable deviation value in the operation process of the air conditioner, a maximum positive value and a minimum negative value of an allowable change value in the operation process of the air conditioner, an output quantity of a membership function when the deviation value reaches the maximum positive value, and an output quantity of the membership function when the change value reaches the maximum positive value.

In some embodiments, the controller is configured to:

and setting the coefficient as a numerical value corresponding to the temperature interval according to the temperature interval of the environment temperature.

In some embodiments, generating the adjustment step number according to the result value and the coefficient specifically includes:

Result＝Result＇/K；

wherein Result is the adjustment step number, Result' is the Result value, and K is the coefficient.

In some embodiments, the controller is further specifically configured to:

if the adjusting step number is larger than 0, opening the expansion valve based on the adjusting step number;

if the adjustment step number is less than 0, closing the expansion valve based on the adjustment step number;

and if the adjusting step number is 0, keeping the current opening degree of the expansion valve.

Correspondingly, the invention also provides an air conditioner control method, which is applied to an air conditioner comprising a refrigerant circulation loop, a compressor, an outdoor heat exchanger, an indoor coil temperature sensor, an outdoor environment temperature sensor, a four-way valve, an exhaust temperature sensor and a controller, and comprises the following steps:

adjusting the expansion valve based on the adjustment steps.

In some embodiments, the membership function comprises at least:

In some embodiments, the determining the coefficient according to the ambient temperature of the outdoor side of the air conditioner includes:

Result＝Result＇/K；

wherein Result is the adjustment step number, Result' is the Result value, and K is the coefficient. In some embodiments, the adjusting the expansion valve based on the number of adjusting steps includes:

Through the technical scheme, the exhaust superheat degree of the air conditioner in the current regulation period is obtained, and a deviation value corresponding to the regulation period is generated according to the exhaust superheat degree and a preset target exhaust superheat degree; determining a variation value between the deviation value corresponding to the adjusting period and the deviation value corresponding to the previous adjusting period; searching a result value corresponding to the deviation value and the change value in a fuzzy control table, wherein the fuzzy control table is generated according to a preset membership function; determining a coefficient according to the ambient temperature of the outdoor side of the air conditioner; generating an adjustment step number according to the result value and the coefficient; the expansion valve is adjusted based on the adjusting step number, so that the air conditioner can adapt to system adjusting requirements under different environmental temperatures and different loads, and the system can reach a balance state by quickly adjusting the expansion valve.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a perspective view showing an external appearance of an air conditioner of an embodiment;

fig. 2 is a circuit diagram showing an outline of the structure of the air conditioner of the embodiment;

fig. 3 is a block diagram showing an outline of the configuration of a control system of an air conditioner;

fig. 4 is a schematic structural diagram illustrating an air conditioner according to an embodiment of the present invention;

fig. 5 is a flowchart illustrating an air conditioner control method according to an embodiment of the present invention;

FIG. 6 is a diagram illustrating a membership function according to an embodiment of the present invention;

fig. 7 is a flowchart illustrating another air conditioner control method according to an embodiment of the present invention.

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, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

In the description of the present application, it is to be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience in describing the present application and simplifying the description, but do not indicate or imply that the referred device or element must have a particular orientation, be constructed in a particular orientation, and be operated, and thus should not be construed as limiting the present application.

The terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present application, "a plurality" means two or more unless otherwise specified.

In the description of the present application, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood in a specific case by those of ordinary skill in the art.

The air conditioner performs a refrigeration cycle of the air conditioner by using a compressor, a condenser, an expansion valve, and an evaporator. 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.

The compressor compresses a 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 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 cooling effect by heat-exchanging with a material to be cooled using latent heat of evaporation of a refrigerant. The air conditioner can adjust the temperature of the indoor space throughout the cycle.

The outdoor unit of the air conditioner refers to a portion of a refrigeration cycle including a compressor and an outdoor heat exchanger, the indoor unit of the air conditioner includes an indoor heat exchanger, and an expansion valve may be provided in the indoor unit or the outdoor unit.

The indoor heat exchanger and the outdoor heat exchanger serve as a condenser or an evaporator. 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 conditioner 1 shown in fig. 1 includes: the indoor unit 3 is exemplified by an indoor unit (shown in the figure), and the indoor unit is usually mounted on an indoor wall surface WL or the like. For another example, an indoor cabinet (not shown) is also an indoor unit of the indoor unit.

The outdoor unit 2 is generally installed outdoors and used for heat exchange in an indoor environment. In the illustration of fig. 1, the outdoor unit 2 is indicated by a broken line because the outdoor unit 2 is located outdoors on the opposite side of the indoor unit 3 with respect to the wall surface WL.

Fig. 2 shows a circuit configuration of an air conditioner 1, and the air conditioner 1 includes a refrigerant circuit 10, and is capable of executing a vapor compression refrigeration cycle by circulating a refrigerant in the refrigerant circuit 10. The indoor unit 3 and the outdoor unit 2 are connected by a connecting pipe 4 to form a refrigerant circuit 10 in which a refrigerant circulates.

Further, as shown in fig. 3, the air conditioner 1 is provided with a control unit 50 for controlling the operation of each component in the air conditioner inside so that each component of the air conditioner 1 operates to realize each predetermined function of the air conditioner. The air conditioner 1 is further provided with a remote controller 5, and the remote controller 5 has a function of communicating with the control unit 50 using, for example, infrared rays or other communication methods. The remote controller 5 is used for various controls of the air conditioner by a user, and interaction between the user and the air conditioner is realized.

To further describe the solution of the present application, as shown in fig. 4, a schematic structural diagram of an air conditioner provided in the embodiment of the present application is specifically:

and an exhaust gas temperature sensor 101 for detecting the exhaust gas temperature.

The controller 102 is configured such that it is,

adjusting the expansion valve based on the adjustment steps.

In order to control the expansion valve more accurately, in the preferred embodiment of the application, the invention provides a control method which can be applied to the expansion valve of the air conditioner. The exhaust superheat degree is used as the target exhaust superheat degree for adjustment, the heat exchange requirement of the air conditioner can be reflected more truly, the opening degree of the expansion valve is adjusted according to the requirement, then the purpose of meeting the requirements of room refrigeration and heating is achieved by adjusting the flow of the refrigerant, in addition, the change of the exhaust superheat degree in the global environment temperature range is much smaller than the change of the exhaust temperature, the calculation and the determination can be simple and convenient, and the control precision is high.

It should be noted that the solution of the above preferred embodiment is only a specific implementation solution proposed in the present application, and only the exhaust temperature sensor and the coil temperatures of the internal machine and the external machine are needed, and it is within the protection scope of the present application to obtain the exhaust superheat degree and the coil temperature in other manners.

In order to more simply obtain the result value for controlling the expansion valve, in the preferred embodiment of the present application, research shows that different processing needs to be performed on the adjustment result of the opening of the expansion valve according to different ambient temperatures, so that the adjustment result needs to be calculated by a fuzzy algorithm, and the purpose of stably adjusting the opening of the expansion valve can still be achieved under the working conditions of the temperatures in all fields. And the unitary quadratic function is used as the membership function, wherein the unitary quadratic function is used as a basic function model, the calculation is relatively simple, and then the unitary quadratic function is converted into the function model, so that the convergence speed is high when the calculation result has large deviation, and the function model is more shock-resistant when the deviation value is small.

The membership function utilized in the present invention to control an expansion valve is shown in figure 6,

where Ψ e is the positive allowed maximum value of the deviation value e, which represents the maximum positive value that the controller can handle during operation, and which will be truncated by the controller when the actual control parameter exceeds this value. ζ e is the exact value of the output when the deviation e is an element of the kernel of the fuzzy set P, i.e. the output corresponding to the maximum positive value of the deviation e. Ω e is the negative allowed maximum value (absolute value) of the deviation e, - Ω e represents the minimum negative value that the controller can handle during operation, and will be truncated by the controller when the actual control parameter exceeds this value. η e is the exact value of the output when the deviation e is the element of the kernel of the fuzzy set N, i.e. the output when the deviation e reaches the minimum negative value. Ψ Δ is the positive allowable maximum of the derivative value Δ e, which represents the maximum positive value that the controller can handle during operation, and will be truncated by the controller when the actual control parameter exceeds this value. ξ Δ is the exact value of the output quantity when the differential value Δ e is an element of the kernel of the fuzzy set P, that is to say the output quantity corresponding to the time at which the differential value Δ e reaches the maximum positive value. Ω Δ is the negative allowed maximum of the differential value Δ e, - Ω Δ represents the minimum that the controller can handle during operation, and will be truncated by the controller when the actual control parameter exceeds this value. η Δ refers to the exact value of the output quantity when the differential value Δ e is an element of the kernel of the fuzzy set P, that is to say the corresponding output quantity when the differential value Δ e reaches a minimum value. e represents the deviation value of the current exhaust superheat degree from the target exhaust superheat degree, and delta e represents the change value of the deviation value and the deviation value at the moment of the last adjusting period.

It should be noted that the above solution of the preferred embodiment is only one specific implementation solution proposed in the present application, and other ways of obtaining the result value of controlling the expansion valve are all within the protection scope of the present application.

In order to obtain the deviation value generated by the exhaust superheat degree and the target exhaust superheat degree, in the preferred embodiment of the application, the exhaust superheat degree of the air conditioner in the current regulation period is obtained, and the deviation value corresponding to the regulation period is generated according to the exhaust superheat degree and the preset target exhaust superheat degree.

Specifically, the method for calculating the preset target exhaust superheat degree in the air conditioner comprises the steps of firstly obtaining the exhaust superheat degree of the current regulation period, and generating a deviation value of the current regulation period according to the target exhaust superheat degree and the exhaust superheat degree of the current regulation period.

It should be noted that the above solution of the preferred embodiment is only one specific implementation solution proposed in the present application, and all preset ways of different target degrees of superheat of exhaust gas belong to the protection scope of the present application.

In a preferred embodiment of the application, a variation value between the deviation value corresponding to the conditioning cycle and the deviation value corresponding to the previous conditioning cycle is determined.

In order to obtain the result value for adjusting the opening degree of the expansion valve, in a preferred embodiment of the present application, the result value corresponding to the deviation value and the variation value is looked up in a fuzzy control table, and the fuzzy control table is generated according to a preset membership function.

Specifically, the fuzzy control table is obtained by performing fuzzification and clarification according to the membership function in fig. 6, and the result value corresponding to the deviation value and the variation value is searched in the fuzzy control table.

It should be noted that the above solution of the preferred embodiment is only a specific implementation solution proposed in the present application, and the generation methods of different fuzzy control tables all belong to the protection scope of the present application.

In a preferred embodiment of the present application, the coefficient is determined according to an ambient temperature of an outdoor side of the air conditioner.

In a preferred embodiment of the application, the number of adjustment steps is generated from the result value and the coefficient.

In a preferred embodiment of the present application, the expansion valve is adjusted based on the number of adjustment steps.

Corresponding to the air conditioner in the embodiment of the present application, the embodiment of the present application further provides an air conditioner control method, where the method is applied to an air conditioner including a refrigerant circulation loop, a compressor, an outdoor heat exchanger, an indoor coil temperature sensor, an outdoor environment temperature sensor, a four-way valve, an exhaust temperature sensor, and a controller, and as shown in fig. 5, the method includes:

step 201, acquiring the exhaust superheat degree of the air conditioner in the current regulation period, and generating a deviation value corresponding to the regulation period according to the exhaust superheat degree and a preset target exhaust superheat degree.

Step 202, determining a variation value between the deviation value corresponding to the adjustment period and the deviation value corresponding to the previous adjustment period.

And 203, searching a result value corresponding to the deviation value and the change value in a fuzzy control table, wherein the fuzzy control table is generated according to a preset membership function.

In a preferred embodiment of the present application, the membership function comprises at least: the air conditioner comprises a maximum positive value and a minimum negative value of an allowable deviation value in the operation process of the air conditioner, a maximum positive value and a minimum negative value of an allowable change value in the operation process of the air conditioner, an output quantity of a membership function when the deviation value reaches the maximum positive value, and an output quantity of the membership function when the change value reaches the maximum positive value.

It should be noted that the solution of the above preferred embodiment is only one specific implementation solution proposed in the present application, and the generation methods of different membership functions all belong to the protection scope of the present application.

In a preferred embodiment of the present application, generating an adjustment step number according to the result value and the coefficient specifically includes: result ═ Result'/K; wherein Result is the adjustment step number, Result' is the Result value, and K is the coefficient.

It should be noted that the scheme of the above preferred embodiment is only one specific implementation scheme proposed in the present application, and the generation methods of different adjustment step numbers all belong to the protection scope of the present application.

In this step, the expansion valve is adjusted based on the adjustment step number, specifically: if the adjusting step number is larger than 0, opening the expansion valve based on the adjusting step number; if the adjustment step number is less than 0, closing the expansion valve based on the adjustment step number; and if the adjusting step number is 0, keeping the current opening degree of the expansion valve.

And step 204, determining a coefficient according to the ambient temperature of the outdoor side of the air conditioner.

In a preferred embodiment of the present application, the determining a coefficient according to the ambient temperature of the outdoor side of the air conditioner specifically includes: and setting the coefficient as a numerical value corresponding to the temperature interval according to the temperature interval of the environment temperature.

It should be noted that the above solution of the preferred embodiment is only one specific implementation solution proposed in the present application, and other methods for determining the coefficients all belong to the protection scope of the present application.

Step 205, generating an adjustment step number according to the result value and the coefficient.

And 206, adjusting the expansion valve based on the adjusting step number.

Corresponding to the air conditioner in the embodiment of the present application, the embodiment of the present application further provides an air conditioner control method, where the method is applied to an air conditioner including a refrigerant circulation loop, a compressor, an outdoor heat exchanger, an indoor coil temperature sensor, an outdoor environment temperature sensor, a four-way valve, an exhaust temperature sensor, and a controller, and as shown in fig. 7, the method includes:

step 301, an expansion valve adjustment function.

Specifically, a membership function for adjusting the opening degree of the expansion valve is preset.

And step 302, adjusting the valve cycle time.

Specifically, step 303 is executed when the expansion valve enters the adjustment time, and step 312 is executed when the expansion valve does not enter the adjustment time.

Step 303, calculating the deviation value e as the current exhaust superheat degree-target exhaust superheat degree.

Specifically, a deviation value e is determined according to the exhaust temperature received by the exhaust temperature sensor and a preset target exhaust degree, when the air conditioner is in a heating mode, the current exhaust superheat degree is equal to the exhaust temperature-the temperature of the indoor side coil, and when the air conditioner is in a cooling mode, the current exhaust superheat degree is equal to the exhaust temperature-the temperature of the outdoor side coil.

In step 304, the variation Δ e is calculated as the deviation at that time — the deviation in the previous cycle.

Specifically, a deviation change value delta e is determined according to the deviation value e and a deviation value in the last cycle of adjusting the expansion valve.

Step 305, searching the fuzzy control table according to the calculation result of the deviation value and the deviation variation value, wherein the search result is result'.

Specifically, the Result obtained by searching the fuzzy control table according to the deviation value and the deviation change value before and after the regulation period is processed according to the difference of the environmental temperature.

At step 306, the outdoor environment is below T2 ℃.

Specifically, it is determined whether the ambient temperature outside the chamber is lower than T2 ℃, if yes, step 308 is executed, and if not, step 307 is executed.

Step 307, the outdoor environment is below T1 ℃.

Specifically, it is determined whether the ambient temperature outside the chamber is lower than T1 ℃, if yes, step 309 is executed, and if not, step 310 is executed.

Step 308, K3.

Specifically, when the ambient temperature of the outdoor side is < T3 ℃, the coefficient K is K3 and step 311 is performed.

In step 309, K is K2.

Specifically, when the ambient temperature on the outdoor side is equal to or higher than T2 ℃, the coefficient K is K2 and step 311 is performed;

at step 310, K — K1 is the coefficient.

Specifically, when the ambient temperature on the outdoor side is equal to or higher than T1 ℃, the coefficient K is K1 and step 311 is performed.

In step 311, the number of adjustment steps of the expansion valve equals Result'/K.

Specifically, step 312 is performed and the number of adjustment steps of the expansion valve is Result'/K.

Step 312, exit.

Specifically, the opening degree of the expansion valve is adjusted according to the adjustment step number of the expansion valve.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit the same; although the present application has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not necessarily depart from the spirit and scope of the corresponding technical solutions in the embodiments of the present application.

Claims

1. An air conditioner, comprising:

an exhaust temperature sensor for detecting an exhaust temperature;

the controller is configured to control the operation of the motor,

adjusting the expansion valve based on the adjustment steps.

2. The air conditioner of claim 1, wherein the membership function includes at least:

3. The air conditioner of claim 1, wherein the controller is further specifically configured to:

4. The air conditioner according to any one of claims 1 to 3, wherein the generation of the adjustment step number based on the result value and the coefficient is specifically:

Result＝Result＇/K；

5. The air conditioner of claim 4, wherein the controller is further configured to:

6. A control method, applied to an air conditioner including a refrigerant circulation circuit, a compressor, an outdoor heat exchanger, an indoor coil temperature sensor, an outdoor ambient temperature sensor, a four-way valve, an exhaust temperature sensor, and a controller, the method comprising:

adjusting the expansion valve based on the adjustment steps.

7. The method of claim 6, wherein the membership function comprises at least:

8. The method according to claim 6, characterized in that the coefficient is determined from the ambient temperature of the outdoor side of the air conditioner, in particular:

9. The method according to any of claims 6 to 8, wherein generating an adjustment step number based on the result value and the coefficient comprises:

Result＝Result＇/K；

10. The method according to claim 9, wherein the expansion valve is adjusted based on the number of adjustment steps, in particular: