Air conditioner and control method thereof, storage medium and computer program product

Abstract

The invention provides an air conditioner and a control method thereof, a storage medium and a computer program product, and the method comprises the following steps: after the air conditioner is refrigerated and started to run, judging whether the air conditioner is in a free running mode or not, and the free running mode is a running mode without a set wind gear; if it is judged that the air conditioner is in the free operation mode, initial operation parameters of the air conditioner are determined, and the air conditioner is controlled to operate according to the determined initial operation parameters; after the air conditioner is controlled to operate for a first preset time according to the determined initial operation parameters, the refrigerating capacity of the air conditioner is determined according to the operation state parameters of the air conditioner; and according to the determined refrigerating capacity of the air conditioner, the rotating speed of an inner fan and / or the rotating speed of an outer fan of the air conditioner are / is controlled. According to the scheme provided by the invention, the problem of low energy efficiency caused by mismatching of the inner fan and the outer fan with the load during free refrigeration operation of the air conditioning system can be avoided, so that the air conditioner always operates in the optimal energy efficiency state.

Description

Technical Field

[0001] This invention relates to the field of control, and more particularly to an air conditioner and its control method, storage medium, and computer program product. Background Art

[0002] According to a report by the International Energy Agency (IEA), air conditioning and other refrigeration equipment account for approximately 10% of global electricity consumption. This proportion is likely to increase with rising global temperatures and increased air conditioning penetration. In recent years, although air conditioning systems have undergone energy efficiency upgrades, the control of most systems is not "intelligent." While their energy efficiency is high under certain operating conditions, during free operation, changes in ambient temperature and indoor load cause the system to deviate from its optimal operating state, resulting in still high energy consumption during free operation. Summary of the Invention

[0003] The main objective of this invention is to overcome the deficiencies of the aforementioned related technologies and provide an air conditioner and its control method, storage medium, and computer program product to solve the problem that when the air conditioner is running freely, changes in ambient temperature and indoor load cause the system's operating state to be not near the optimal matching point, resulting in high energy consumption of the air conditioning system.

[0004] This invention provides a method for controlling an air conditioner, comprising: after the air conditioner is turned on for cooling operation, determining whether the air conditioner is in a free operation mode, wherein the free operation mode is an operation mode without a set fan speed; if the air conditioner is determined to be in a free operation mode, determining the initial operating parameters of the air conditioner and controlling the air conditioner to operate according to the determined initial operating parameters; after controlling the air conditioner to operate according to the determined initial operating parameters for a first preset time, determining the cooling capacity of the air conditioner based on the operating status parameters of the air conditioner; and controlling the speed of the indoor fan and / or the speed of the outdoor fan of the air conditioner based on the determined cooling capacity of the air conditioner.

[0005] Optionally, it further includes: after the air conditioner is turned on for cooling, if it is determined that the air conditioner is in free operation mode, first control the indoor fan of the air conditioner to start, and determine the initial operating parameters of the air conditioner when the indoor fan is started.

[0006] Optionally, the initial operating parameters include at least one of the following: compressor initial frequency, indoor fan initial speed, outdoor fan initial speed, and throttling device initial opening degree; controlling the air conditioner to operate according to the determined initial operating parameters includes: controlling the air conditioner to enter the oil return mode, and according to the determined compressor initial frequency and the set oil return frequency; controlling the air conditioner's compressor to operate according to the compressor initial frequency or according to the set oil return frequency; controlling the air conditioner's indoor fan and outdoor fan to operate according to the determined indoor fan initial speed and outdoor fan initial speed, respectively; and controlling the opening degree of the air conditioner's throttling device according to the compressor's oil return frequency during oil return.

[0007] Optionally, the operating status parameters include at least one of: evaporator tube temperature, condenser tube temperature, condenser outlet temperature, and exhaust temperature; determining the cooling capacity of the air conditioner based on the operating status parameters includes: calculating the suction saturation temperature based on the compressor frequency, evaporator tube temperature, and saturation pressure drop from the middle of the evaporator to the compressor suction port; calculating the suction dryness based on the compressor frequency, suction saturation temperature, exhaust temperature, and condenser tube temperature; and calculating the superheated suction specific volume v based on the calculated suction dryness. suc Or two-phase intake specific volume v suc The compressor volumetric efficiency is calculated based on the compressor frequency, condenser tube temperature, and evaporator tube temperature. The circulating refrigerant flow rate in the system is calculated based on the superheated suction specific volume or two-phase suction specific volume, combined with the compressor cylinder volume, compressor frequency, and compressor volumetric efficiency. The cooling capacity of the air conditioner is calculated based on the calculated circulating refrigerant flow rate, suction dryness, suction saturation temperature, and the detected condenser outlet temperature.

[0008] Optionally, based on the determined cooling capacity of the air conditioner, controlling the speed of the indoor fan and / or the speed of the outdoor fan includes: calculating the indoor fan speed corresponding to the cooling capacity according to a preset relationship model between cooling capacity and indoor fan speed, and / or calculating the outdoor fan speed corresponding to the cooling capacity according to a preset relationship model between cooling capacity and outdoor fan speed; controlling the indoor fan of the air conditioner to operate at the calculated indoor fan speed, and / or controlling the outdoor fan of the air conditioner to operate at the calculated outdoor fan speed.

[0009] Optionally, it further includes: after controlling the air conditioner to run for a first preset time according to the determined initial operating parameters, performing PID control on the compressor frequency and throttling device opening of the air conditioner, including: performing PID control on the compressor frequency of the air conditioner according to the indoor ambient temperature and the set temperature of the air conditioner; and / or, performing PID control on the air conditioner and the throttling device opening according to the exhaust temperature of the air conditioner compressor and the target exhaust temperature.

[0010] Optionally, PID control is performed on the compressor frequency of the air conditioner based on the indoor ambient temperature and the set temperature of the air conditioner, including: adjusting the compressor frequency based on the real-time detected difference between the indoor ambient temperature and the set temperature and the corresponding rate of change of the difference between the indoor ambient temperature and the set temperature; and / or, PID control is performed on the opening degree of the air conditioner and the throttling device based on the exhaust temperature of the air conditioner compressor and the target exhaust temperature, including: adjusting the opening degree of the throttling device based on the real-time detected difference between the exhaust temperature and the target exhaust temperature and the rate of change of the difference between the exhaust temperature and the target exhaust temperature.

[0011] In another aspect, the present invention provides a control device for an air conditioner, comprising: a judgment unit, configured to determine whether the air conditioner is in a free operation mode after the air conditioner is turned on for cooling, wherein the free operation mode is an operation mode without a set fan speed; a control unit, configured to determine the initial operating parameters of the air conditioner and control the air conditioner to operate according to the determined initial operating parameters if the judgment unit determines that the air conditioner is in a free operation mode; a determination unit, configured to determine the cooling capacity of the air conditioner based on the operating status parameters of the air conditioner after the control unit controls the air conditioner to operate according to the determined initial operating parameters for a first preset time; the control unit is further configured to: control the speed of the indoor fan and / or the speed of the outdoor fan of the air conditioner based on the cooling capacity of the air conditioner determined by the determination unit.

[0012] Optionally, it is also used to: after the air conditioner is turned on for cooling, if the judgment unit determines that the air conditioner is in free operation mode, first control the indoor fan of the air conditioner to start, and determine the initial operating parameters of the air conditioner when the indoor fan is started.

[0013] Optionally, the initial operating parameters include at least one of the following: compressor initial frequency, indoor fan initial speed, outdoor fan initial speed, and throttling device initial opening degree; the control unit controls the air conditioner to operate according to the determined initial operating parameters, including: controlling the air conditioner to enter the oil return mode, and according to the determined compressor initial frequency and the set oil return frequency; controlling the air conditioner's compressor to operate according to the compressor initial frequency or according to the set oil return frequency; controlling the air conditioner's indoor fan and outdoor fan to operate according to the determined indoor fan initial speed and outdoor fan initial speed, respectively; and controlling the opening degree of the air conditioner's throttling device according to the compressor's oil return frequency during oil return.

[0014] Optionally, the operating status parameters include at least one of the following: evaporator tube temperature, condenser tube temperature, condenser outlet temperature, and exhaust temperature; the determining unit determines the cooling capacity of the air conditioner based on the operating status parameters, including: calculating the suction saturation temperature based on the compressor frequency, evaporator tube temperature, saturation pressure drop from the middle of the evaporator to the compressor suction port; calculating the suction dryness based on the compressor frequency, suction saturation temperature, exhaust temperature, and condenser tube temperature; calculating the superheated suction specific volume or two-phase suction specific volume based on the calculated suction dryness; calculating the compressor volumetric efficiency based on the compressor frequency, condenser tube temperature, and evaporator tube temperature; calculating the circulating refrigerant flow rate in the system based on the superheated suction specific volume or two-phase suction specific volume, combined with the compressor cylinder volume, compressor frequency, and compressor volumetric efficiency; and calculating the cooling capacity of the air conditioner based on the calculated circulating refrigerant flow rate in the system, suction dryness, suction saturation temperature, and the detected condenser outlet temperature.

[0015] Optionally, the control unit controls the indoor fan speed and / or outdoor fan speed of the air conditioner according to the cooling capacity determined by the determining unit, including: calculating the indoor fan speed corresponding to the cooling capacity according to a preset relationship model between cooling capacity and indoor fan speed, and / or calculating the outdoor fan speed corresponding to the cooling capacity according to a preset relationship model between cooling capacity and outdoor fan speed; controlling the indoor fan of the air conditioner to operate at the calculated indoor fan speed, and / or controlling the outdoor fan of the air conditioner to operate at the calculated outdoor fan speed.

[0016] Optionally, the control unit is further configured to: after controlling the air conditioner to run for a first preset time according to the determined initial operating parameters, perform PID control on the compressor frequency and throttling device opening of the air conditioner, including: performing PID control on the compressor frequency of the air conditioner according to the indoor ambient temperature and the set temperature of the air conditioner; and / or, performing PID control on the compressor frequency and throttling device opening of the air conditioner according to the exhaust temperature of the compressor and the target exhaust temperature of the air conditioner.

[0017] Optionally, the control unit performs PID control on the compressor frequency of the air conditioner based on the indoor ambient temperature and the set temperature of the air conditioner, including: adjusting the compressor frequency based on the real-time detected difference between the indoor ambient temperature and the set temperature and the corresponding rate of change of the difference between the indoor ambient temperature and the set temperature; and / or, the control unit performs PID control on the opening degree of the air conditioner and the throttling device based on the exhaust temperature of the air conditioner compressor and the target exhaust temperature, including: adjusting the opening degree of the throttling device based on the real-time detected difference between the exhaust temperature and the target exhaust temperature and the rate of change of the difference between the exhaust temperature and the target exhaust temperature.

[0018] In another aspect, the present invention provides a storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of any of the methods described above.

[0019] In another aspect, the present invention provides an air conditioner, including a processor, a memory, and a computer program stored in the memory that can run on the processor, wherein the processor executes the program to implement the steps of any of the methods described above.

[0020] In another aspect, the present invention provides an air conditioner including any of the control devices described above.

[0021] In another aspect, the present invention provides a computer program product, including a computer program that, when executed by a processor, implements the steps of any of the methods described above.

[0022] According to the technical solution of the present invention, when the air conditioner is in free operation mode, the cooling capacity of the air conditioner is determined according to the operating status parameters of the air conditioner, and the speed of the indoor fan and / or the speed of the outdoor fan of the air conditioner is controlled according to the cooling capacity of the air conditioner. This can avoid the problem of low energy efficiency caused by the mismatch between the indoor and outdoor fans and the load when the air conditioning system is in free operation, and make the air conditioner always operate in the optimal energy efficiency state.

[0023] According to the technical solution of the present invention, the air conditioning capacity can be calculated in real time based on the detected air conditioning operating status parameters and the building load, and the speed of the indoor and outdoor fans can be dynamically adjusted according to the cooling capacity of the air conditioning, so that the air conditioning system can operate efficiently and stably near the optimal state point under any operating condition, thereby reducing system energy consumption. Attached Figure Description

[0024] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings:

[0025] Figure 1 This is a schematic diagram of an embodiment of the air conditioner control method provided by the present invention;

[0026] Figure 2 A flowchart illustrating a specific implementation of the steps for determining the cooling capacity of an air conditioner based on its operating status parameters is provided.

[0027] Figure 3 This is a schematic diagram of the process for controlling the speed of the internal and external fans and for performing PID control on the compressor frequency and the opening degree of the throttling device according to a specific embodiment of the present invention.

[0028] Figure 4 This is a schematic diagram of another embodiment of the air conditioner control method provided by the present invention;

[0029] Figure 5 This is a schematic diagram of a specific embodiment of the air conditioner control method provided by the present invention;

[0030] Figure 6 This is a structural block diagram of an embodiment of the air conditioner control device provided by the present invention. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0032] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0033] The high energy consumption of variable frequency air conditioning systems during free-running is mainly due to two reasons: first, the speed and capacity of the indoor and outdoor fans are mismatched, and they are not near their optimal speeds; second, the opening of the electronic expansion valve is unreasonable, failing to fully utilize the heat exchanger's heat exchange performance. Increasing the airflow is an effective way to improve the heat exchanger's heat exchange capacity and system energy efficiency, but increasing the airflow also increases the fan power, and system energy efficiency does not necessarily improve linearly. Therefore, the speed of the indoor and outdoor fans in the air conditioning system must be matched with the load to achieve optimal system energy efficiency.

[0034] Figure 1 This is a schematic diagram of an embodiment of the air conditioner control method provided by the present invention.

[0035] like Figure 1 As shown, according to an embodiment of the present invention, the air conditioner control method includes at least steps S110, S120, S130 and S140.

[0036] Step S110: After the air conditioner starts cooling, determine whether the air conditioner is in free operation mode.

[0037] Specifically, after the air conditioner receives the instruction to start and operate in cooling mode, it determines whether it is in free operation mode. The free operation mode is specifically a mode without a set fan speed, that is, no fan speed is set, and the speed of the indoor fan changes according to the changes in the air conditioner's operating status during operation.

[0038] Step S120: If it is determined that the air conditioner is in free operation mode, then the initial operating parameters of the air conditioner are determined, and the air conditioner is controlled to operate according to the determined initial operating parameters.

[0039] Specifically, indoor and outdoor environmental parameters are detected, and based on these parameters and the air conditioner's settings, the initial operating parameters of the air conditioner are determined. These indoor and outdoor environmental parameters may specifically include: indoor ambient temperature (specifically, the indoor return air dry-bulb temperature) T. ain and outdoor ambient temperature T aout The setting parameters may specifically include: setting temperature T. set Specifically, after the air conditioner is turned on for cooling, the indoor fan is first started. With the indoor fan running, the initial operating parameters of the air conditioner are determined. That is, with the indoor fan running, indoor and outdoor environmental parameters are detected, and the initial operating parameters are determined based on the detected indoor and outdoor environmental parameters and the air conditioner's set parameters. Starting the indoor fan prevents inaccurate detection of environmental parameters due to uneven indoor temperature fields. The air conditioner's temperature sensor readings are affected by various factors such as installation location and indoor temperature field distribution. Starting the indoor fan makes the temperature field more uniform and the detection more accurate. The indoor fan can be started at the set indoor fan speed of the ventilation mode (i.e., the default indoor fan speed of the ventilation mode).

[0040] Preferably, after the indoor fan is started at its initial speed, the detected indoor ambient temperature (e.g., indoor dry-bulb temperature T) is compared. ain ) and set temperature T set The size of T ain -T set When T ≤ a (a≤0℃), it means the indoor ambient temperature is lower than the user-set temperature. In this case, the compressor does not need to be turned on; the outdoor fan and compressor will not start, and only ventilation mode will operate. ain -T set When >a, the initial operating parameters of the air conditioner are determined based on the detected indoor and outdoor environmental parameters and the setting parameters of the air conditioner.

[0041] In one specific implementation, based on a set temperature T set With indoor ambient temperature T ainTemperature difference ΔT1=T ain -T set and / or outdoor ambient temperature T aout With indoor ambient temperature T ain Temperature difference ΔT2=T aout -T ain The initial operating parameters of the air conditioner are determined.

[0042] Specifically, different set temperatures T set With indoor ambient temperature T ain Temperature difference ΔT1=T ain -T set and / or outdoor ambient temperature T aout With indoor ambient temperature T ain Temperature difference ΔT2=T aout -T ain The preset temperature T can be set according to different initial operating parameters. set With indoor ambient temperature T ain Temperature difference ΔT1=T ain -T set and / or outdoor ambient temperature T aout With indoor ambient temperature T ain Temperature difference ΔT2=T aout -T ain The correspondence with the initial operating parameters of the air conditioner (e.g., setting different set temperatures T). set With indoor ambient temperature T ain Temperature difference range and / or outdoor ambient temperature T aout With indoor ambient temperature T ain The temperature difference range corresponds to the initial operating parameters of the air conditioner, based on the set temperature T. set With indoor ambient temperature T ain Temperature difference ΔT1=T ain -T set and / or outdoor ambient temperature T aout With indoor ambient temperature T ain Temperature difference ΔT2=T aout -T ain To find the correspondence between the measured indoor ambient temperature T and the initial operating parameters of the air conditioner. ain and / or outdoor ambient temperature T aout The corresponding initial operating parameters of the air conditioner.

[0043] The initial operating parameters may specifically include: compressor initial frequency f, and internal fan initial speed N. o Initial speed of external fan N i And the initial opening degree n of the throttling device (electronic expansion valve)v At least one of them. The initial opening degree of the throttling device is determined based on the compressor frequency.

[0044] Based on the detected indoor and outdoor environmental parameters and the air conditioner's set parameters, the initial operating parameters of the air conditioner are determined, and the air conditioner is controlled to operate according to these initial operating parameters. Among these, the initial speed N of the outdoor fan is... i Upon startup, the compressor starts running at its initial frequency f, and the internal fan starts running at its initial speed N. o The operating, throttling device (electronic expansion valve) is set at an initial opening n. v run.

[0045] Preferably, the air conditioner is first controlled to enter the oil return mode. Based on the determined initial compressor frequency and the set oil return frequency, the air conditioner's compressor is controlled to operate at either the initial compressor frequency or the set oil return frequency. The indoor and outdoor fans are controlled to operate at their determined initial speeds, respectively. The opening degree of the air conditioner's throttling device (electronic expansion valve) is controlled according to the oil return frequency of the compressor during oil return, wherein different oil return frequencies correspond to different initial opening degrees of the throttling device. Specifically, when the determined initial compressor frequency f is greater than the set oil return frequency, the compressor is controlled to start operating at the initial compressor frequency; when the initial compressor frequency f is less than the set oil return frequency, the compressor is controlled to start operating at the set oil return frequency. After the air conditioner operates according to the determined initial operating parameters for a first preset time, it exits the oil return mode.

[0046] Step S130: After controlling the air conditioner to run for a first preset time according to the determined initial operating parameters, determine the cooling capacity of the air conditioner based on the operating status parameters of the air conditioner.

[0047] Specifically, after the air conditioner operates according to the determined initial operating parameters for a first preset time (e.g., entering oil return mode and operating for a first preset time before exiting oil return mode), the cooling capacity of the air conditioner is calculated based on the compressor frequency and the air conditioner's operating status parameters. Based on the calculated cooling capacity, the speed of the indoor fan and / or the outdoor fan of the air conditioner is controlled. The operating status parameters may specifically include: compressor frequency f, evaporator (indoor heat exchanger) pipe temperature (specifically, the temperature within the evaporator pipes) T. e Condenser (outdoor heat exchanger) tube temperature (specifically, the temperature inside the condenser tubes) T c Condenser outlet temperature T C,out and exhaust temperature T dis .

[0048] Figure 2A flowchart illustrating a specific embodiment of the steps for determining the cooling capacity of an air conditioner based on its operating status parameters is provided.

[0049] like Figure 2 As shown, the cooling capacity of the air conditioner can be calculated based on the operating status parameters of the air conditioner, following these steps:

[0050] Step S131, based on the compressor frequency f and evaporator tube temperature T e and the saturation temperature drop dT from the middle of the evaporator to the compressor suction port sat,e Calculate the intake saturation temperature T sucsat .

[0051] In one specific implementation, the saturation temperature drop dT from the middle of the evaporator to the compressor suction port can be calculated using the following fitted relationship. sat,e :

[0052] dT sat,e =f(f)=(C0+C1f+C2f) 2 )

[0053] In one specific implementation, the compressor frequency f and the evaporator tube temperature T can be used as the basis. e The intake saturation temperature T is calculated using the following fitted relationship. sucsat :

[0054] T sucsat =f(T) e f) = T e -(C0+C1f+C2f) 2 )

[0055] Among them, T sucsat dT is the intake saturation temperature (°C), f is the compressor frequency (Hz), and dT is the compressor frequency (Hz). sat,e T represents the saturation temperature drop from the middle of the evaporator to the compressor suction port (unit: °C). e C0, C1, and C2 are the evaporator tube temperature (unit: °C), and the values ​​of the same fitting coefficients in different fitting formulas in this invention are different.

[0056] Step S132, based on the compressor frequency f and the suction saturation temperature T sucsat Exhaust temperature T dis and the temperature T in the condenser tube c Calculate the inhaled dryness fraction x suc .

[0057] In one specific implementation, the inspiratory dryness fraction x can be calculated using the following fitting formula. suc :

[0058] xsuc =f(f,T) sucsat T C T dis )=C0+C1f+C2T sucsat +C3T c +C4T dis

[0059] Where f is the compressor operating frequency (unit: Hz), T sucsat T is the intake saturation temperature (°C). c T represents the temperature inside the condenser tubes (unit: °C). dis Where is the exhaust temperature (°C), and C0, C1, C2, C3, and C4 are fitting coefficients. In this invention, the values ​​of the same fitting coefficients in different fitting formulas are different.

[0060] Step S133, based on the calculated inhalation dryness x suc The size of the superheated gas absorbance specific volume v is calculated. suc Or two-phase intake specific volume v suc .

[0061] Among them, if the inhalation dryness x suc If the value is greater than or equal to 1, then calculate the superheated gas absorption specific volume v. suc If the inhalation dryness is x suc If the value is less than 1, then calculate the two-phase intake specific volume v. suc .

[0062] Specifically, if the inhalation is overheated, i.e., the inhalation dryness is x suc If the value is greater than or equal to 1, then based on the compressor frequency f and the suction saturation temperature T... sucsat Exhaust temperature T dis and the temperature T in the condenser tube c Calculate the intake superheat ΔT sucsh According to the intake superheat ΔT sucsh Intake saturation temperature T sucsat and inspiratory saturation specific volume v sucgsat Calculate the superheated gas specific volume v suc .

[0063] In one specific implementation, the intake superheat ΔT can be calculated using the following fitted relationship. sucsh :

[0064] ΔT sucsh =f(f,T) sucsat T C T dis )=C0+C1f+C2T sucsat +C3T c +C4T dis ;

[0065] Where f is the compressor operating frequency, T sucsat T is the intake saturation temperature. c T represents the temperature inside the condenser tubes. dis Where C is the exhaust temperature, and C0, C1, C2, C3, and C4 are fitting coefficients. In this invention, the values ​​of the same fitting coefficients in different fitting equations are different.

[0066] In one specific implementation, the superheated gas absorption specific volume v can be calculated using the following fitting relationship. suc (Unit: m) 3 / kg):

[0067] v suc =f(T) sucsat ΔT sucsh v sucgsat )=(C0+C1T sucsat +C2ΔT sucsh )×v sucgsat

[0068] Among them, v sucgsat Specific volume of saturated inhaled gas, unit: m³ 3 / kg, depending on the inhalation saturation temperature T sucsat Calculate using the following fitted relationship:

[0069] v sucgsat =f(T) sucsat )=1 / (C0+C1T sucsat +C2T sucsat +C3T sucsat );

[0070] Wherein, C0, C1, C2, and C3 are fitting coefficients, and the values ​​of the same fitting coefficients in different fitting formulas in this invention are different.

[0071] If the inhaled air contains liquid, i.e., the inhaled dryness is x suc If it is less than 1, then it is based on the inhalation dryness x suc Specific volume of inhaled saturated gas v sucgsat Specific volume v of saturated uptake liquid suclsat Calculate the two-phase intake specific volume v suc C0, C1, and C2 are fitting coefficients. In this invention, the values ​​of the same fitting coefficients in different fitting relationships are different.

[0072] In one specific implementation, the two-phase absorbance specific volume (unit: m³) can be calculated using the following fitting formula. 3 / kg):

[0073] v suc =f(x) suc v suclsat vsucgsat )=(1-x suc )v suclsat +x suc v sucgsat )

[0074] Among them, v suclsat Specific volume of the saturated absorbent liquid, unit: m³ 3 / kg, depending on the inhalation saturation temperature T sucsat Calculate using the following fitted relationship:

[0075] v suclsat =f(T) sucsat )=1 / (C0+C1T sucsat +C2T sucsat );

[0076] Wherein, C0, C1, and C2 are fitting coefficients, and the values ​​of the same fitting coefficients in different fitting relationships in this invention are different.

[0077] Step S134, based on the compressor frequency f and condenser tube temperature T c and evaporator tube temperature T e Calculate the compressor volumetric efficiency η v .

[0078] In one specific implementation, the compressor volumetric efficiency η can be calculated using the following fitted relationship. v :

[0079] η v =f(f,T) C T e )=C0+C1f+C2T c +C3T e

[0080] Wherein, C0, C1, and C2 are fitting coefficients, and the values ​​of the same fitting coefficients in different fitting relationships in this invention are different.

[0081] Step S135, based on the superheated intake specific volume v suc Or two-phase intake specific volume v suc Combined with compressor cylinder volume V rev compressor frequency f and compressor volumetric efficiency η v Calculate the circulating refrigerant flow rate M in the system. r .

[0082] Specifically, if the inhalation dryness x suc Greater than or equal to 1, based on the compressor cylinder volume V rev (Preset value), Superheated intake specific volume v suc Compressor frequency f and compressor volumetric efficiency η vCalculate the circulating refrigerant flow rate M in the system. r If the inhalation dryness is x suc Less than 1, based on the compressor cylinder volume V rev Two-phase intake specific volume v suc Compressor frequency f and compressor volumetric efficiency η v Calculate the circulating refrigerant flow rate M in the system. r .

[0083] In one specific implementation, the circulating refrigerant flow rate M in the system can be calculated using the following fitted relationship. r :

[0084] M r =f(V rev v suc , f, η v ) = V rev / v suc ×f×η v

[0085] Since the compressor frequency is measured in revolutions per second (rpm), while the flow rate is measured in kg / h, it needs to be multiplied by 3600 to convert it to hours, i.e., M. r =V rev / v suc ×f×η v ×3600.

[0086] Step S136, based on the calculated circulating refrigerant flow rate M in the system r Inhalation dryness x suc and inhalation saturation temperature T sucsat And the detected condenser outlet temperature T c_out Calculate the cooling capacity Q of the air conditioner.

[0087] First, based on the condenser outlet temperature T c_out Calculate the specific enthalpy h at the condenser outlet of the refrigeration system. c_out (Unit: kJ / kg). In one specific embodiment, the condenser outlet temperature T can be used as a reference. c_out The condenser outlet specific enthalpy h of the refrigeration system is calculated using the following fitted relationship. c_out :

[0088] h c_out =f(T) C_out )=C0+C1T c_out +C2T 2 c_out +C3T 3 c_out

[0089] Wherein, C0, C1, C2, and C3 are fitting coefficients, and the values ​​of the same fitting coefficients in different fitting formulas in this invention are different.

[0090] Then, based on the inhalation saturation temperature T sucsat Calculate the saturated intake enthalpy h sucgsat (Unit: kJ / kg) and enthalpy of saturated liquid absorption ratio (h) suclsat (Unit: kJ / kg);

[0091] In one specific implementation, the intake saturation temperature T can be used as a reference. sucsat The saturated uptake ratio enthalpy h is calculated using the following fitted relationship. sucgsat :

[0092] h sucgsat =f(T) sucsat )=C0+C1T sucsat +C2T 2 sucsat +C3T 3 sucsat

[0093] Wherein, C0, C1, C2, and C3 are fitting coefficients, and the values ​​of the same fitting coefficients in different fitting formulas in this invention are different.

[0094] In one specific implementation, the intake saturation temperature T can be used as a reference. sucsat The saturated liquid uptake enthalpy h is calculated using the following fitted relationship. suclsat :

[0095] h suclsat =f(T) sucsat )C0+C1T sucsat +C2T 2 sucsat +C3T 3 sucsat

[0096] Wherein, C0, C1, C2, and C3 are fitting coefficients, and the values ​​of the same fitting coefficients in different fitting formulas in this invention are different.

[0097] Then, based on the inspiratory dryness x suc saturated inhalation enthalpy h sucgsat Enthalpy of saturated liquid absorption h suclsat Calculate the suction enthalpy h of the refrigeration system suc (Unit: kJ / kg). In one specific embodiment, the suction enthalpy h of the refrigeration system can be calculated using the following fitting formula. suc :

[0098] h suc =f(x) suc hsuclsat h sucgsat )=(1-x suc )h suclsat +x suc h sucgsat

[0099] Finally, based on the calculated condenser outlet specific enthalpy h of the refrigeration system... c_out Enthalpy h of the suction gas of the refrigeration system suc Calculate the cooling capacity Q of the air conditioner, that is, the cooling ability Q (unit: W):

[0100] Q = M r ×(h suc -h c_out ) / 3.6

[0101] The cooling capacity of the air conditioner, i.e., the cooling volume Q, can be calculated by following the steps described above.

[0102] Step S140: Based on the determined cooling capacity of the air conditioner, control the speed of the indoor fan and / or the speed of the outdoor fan of the air conditioner.

[0103] Specifically, the indoor fan speed corresponding to the cooling capacity is calculated according to a preset model of the relationship between cooling capacity and indoor fan speed, and / or the outdoor fan speed corresponding to the cooling capacity is calculated according to a preset model of the relationship between cooling capacity and outdoor fan speed; the indoor fan of the air conditioner is controlled to operate at the calculated indoor fan speed, and / or the outdoor fan of the air conditioner is controlled to operate at the calculated outdoor fan speed. The calculated cooling capacity of the air conditioner is then substituted into the preset model of the relationship between cooling capacity and indoor and / or outdoor fan speeds to calculate the indoor fan speed and / or outdoor fan speed corresponding to the cooling capacity of the air conditioner.

[0104] The cooling capacity Q and the internal fan speed N i The relational model can specifically be:

[0105] N i =f(Q)=C0+C1*Q;

[0106] The cooling capacity and the external fan speed N o The relational model body can specifically be:

[0107] N o =f(Q)=C0+C1*Q;

[0108] Wherein, C0 and C1 are fitting coefficients, and the values ​​of the same fitting coefficients in different fitting relationships in this invention are different.

[0109] Based on the calculated cooling capacity Q of the air conditioner, the optimal indoor and outdoor fan speeds Ni and No can be obtained according to the above relationship model.

[0110] The cooling capacity Q of the air conditioner is calculated in real time, and the corresponding indoor and outdoor fan speeds Ni and No are obtained according to the relationship model based on the calculated cooling capacity. The indoor and outdoor fans are controlled according to the calculated indoor and outdoor fan speeds Ni and No.

[0111] Preferably, the average cooling capacity Qave of the air conditioner is calculated every third preset time interval (within the previous third preset time interval). Based on the calculated average cooling capacity Qave, the corresponding indoor and outdoor fan speeds Ni and No are calculated according to a relational model, and the indoor and outdoor fans are controlled according to the calculated indoor and outdoor fan speeds Ni and No. The control process for the above-mentioned indoor and outdoor fans can be referred to... Figure 3 As shown.

[0112] Figure 4 This is a schematic diagram of another embodiment of the air conditioner control method provided by the present invention.

[0113] like Figure 4 As shown, according to another embodiment of the present invention, the air conditioner control method further includes step S150.

[0114] Step S150: After controlling the air conditioner to run for a first preset time according to the determined initial operating parameters, perform PID control on the compressor frequency and throttling device opening of the air conditioner.

[0115] Specifically, after controlling the air conditioner to run for a first preset time according to the determined initial operating parameters, the oil return mode is exited, and the compressor frequency and throttling device opening of the air conditioner are controlled by PID.

[0116] In one specific embodiment, the compressor frequency f of the air conditioner is controlled by PID based on the indoor ambient temperature and the set temperature of the air conditioner. Specifically, based on the real-time detected indoor ambient temperature (indoor dry-bulb temperature) T... ain With the set temperature T ain_sett The difference ΔT ain (ΔT ain =T ain -T ain_set) and the corresponding rate of change δT of the difference between the indoor ambient temperature and the set temperature. ain (δT ain =ΔT ain(n) -ΔT ain(n-1) Adjust the compressor frequency.

[0117] More specifically, for the compressor frequency f, every second preset time interval, the indoor ambient temperature Tain and the set temperature T are detected in real time. ain_set The difference ΔTain(ΔT) ain =T ain -T ain_set ) and the corresponding rate of change of the difference between the indoor ambient temperature and the set temperature δTain(δT) ain =ΔT ain(n) -ΔT ain(n-1) Every third preset time interval (the third preset time interval is an integer multiple of the second preset time interval), calculate the indoor ambient temperature T (within the first third preset time interval). ain With the set temperature T set Difference ΔT ain The average value (ΔT) ain_ave ={T ain -T ain_set}) and the average rate of change δTain(δT) of the difference between the indoor ambient temperature and the set temperature. ain_ave ={ΔT ain(n) -ΔT ain(n-1) According to the calculated indoor ambient temperature T ain With the set temperature T set Difference ΔT ain The average value ΔT ain_ave And the average rate of change δT of the difference between the indoor ambient temperature and the set temperature. ain_ave The compressor frequency f is adjusted, where the adjustment amount of the compressor frequency is δf = k f1 ×ΔT ain_ave +k f2 ×δT ain_ave , where k f1 and k f2 It is a constant and can be obtained experimentally.

[0118] In one specific embodiment, the opening degree n of the air conditioner and its throttling device is adjusted based on the exhaust temperature of the air conditioner's compressor and the target exhaust temperature. v PID control is implemented. Specifically, based on the real-time detected exhaust temperature T... dis With the target exhaust temperature T dis_tar The difference and the rate of change δT of the difference between the exhaust temperature and the target exhaust temperature. dis_tar (δT dis_tar =ΔT dis_tar (n)-ΔT dis_tar (n-1)) The opening degree n of the throttling device (electronic expansion valve) v Adjustments were made.

[0119] More specifically, for the opening degree n of the electronic expansion valve vThe exhaust temperature T is monitored in real time every second preset time interval. dis With the target exhaust temperature T dis_tar The difference ΔT dis_tar and the rate of change δT of the difference between the exhaust temperature and the target exhaust temperature. dis_tar (δT dis_tar =ΔT dis_tar (n)-ΔT dis_tar (n-1)); Every third preset time interval (the third preset time interval is an integer multiple of the second preset time interval), calculate the exhaust temperature T (within the first third preset time interval). dis With the target exhaust temperature T dis_tar The difference (ΔT) dis =T dis -T dis_tar The average value ΔT dis_ave (ΔT dis_ave ={T dis -T dis_tar}, and the average rate of change δT of the difference between the exhaust temperature and the target exhaust temperature. dis_ave (δT dis_ave ={ΔT dis (n)-ΔT dis (n-1)} is adjusted, where the opening adjustment amount of the throttling device (e.g., electronic expansion valve) is δnv=k nv1 ×ΔT dis_ave +k nv2 ×δT dis_ave , where k nv1 and k nv2 It is a constant and can be obtained experimentally.

[0120] After performing PID control on the compressor frequency and throttling device opening of the air conditioner, it is determined whether the absolute value of the difference between the indoor temperature and the set temperature, |ΔTain|, is less than or equal to the preset difference threshold corresponding to the corresponding operating parameter (i.e., the compressor frequency and throttling device correspond to different preset difference thresholds, for example, the preset difference threshold corresponding to the compressor frequency is x, and the preset difference threshold corresponding to the throttling device opening is z). If yes, the current operating parameters are maintained; otherwise, PID control continues.

[0121] The above-described PID control process for compressor frequency and throttling device opening can also be referenced. Figure 3 As shown.

[0122] When the indoor temperature T ain With the set temperature T setWhen the absolute value of the difference is less than or equal to the preset temperature value x (|Tain-Tset|≤x), the air conditioner is determined to have entered a stable state, and the steps of the method of the present invention are returned to be executed again. Otherwise, the internal and external fan speed control and / or the compressor frequency and throttling device opening degree are controlled by PID.

[0123] To clearly illustrate the technical solution of the present invention, the execution flow of the air conditioner control method provided by the present invention will be described below with reference to a specific embodiment.

[0124] Figure 5 This is a schematic diagram of a specific embodiment of the air conditioner control method provided by the present invention. Figure 5 As shown, after receiving the start-up command for cooling mode, the air conditioner determines whether it is in free-running mode (no fan speed setting). In free-running mode, the user-set temperature T is used. set After the operation command is issued, the indoor fan of the air conditioning system starts (the indoor fan starts at the preset initial speed) and detects indoor and outdoor operating parameters, including indoor ambient temperature (indoor return air dry-bulb temperature) T. ain and outdoor ambient temperature T aout Compare indoor ambient temperature T ain With the set temperature T set The size of T ain -T set When T ≤ a (a≤0℃), it means the indoor ambient temperature is lower than the user-set temperature. In this case, the compressor does not need to be turned on; it will not start and will only operate in ventilation mode. ain -T set When >a, the difference between the set temperature and the indoor ambient temperature is ΔT1 = T. ain -T set and outdoor ambient temperature T aout With indoor ambient temperature T ain The difference ΔT2 = T aout -T set Determine the initial compressor frequency f, the initial speed No of the internal fan, the initial speed Ni of the external fan, and the opening degree nv of the electronic expansion valve.

[0125] Subsequently, the compressor enters the oil return phase. During oil return, the indoor and outdoor fans operate at their initial speeds no and ni, respectively. When the initial compressor frequency f is greater than the default oil return frequency, the compressor starts at the initial frequency; when the initial compressor frequency f is less than the default oil return frequency, the compressor starts at the default oil return frequency. During oil return, the opening degree of the electronic expansion valve corresponds to different electronic expansion valve opening degrees depending on the different oil return frequencies.

[0126] After the system runs for t1 time at the above-mentioned frequency, opening degree, and internal and external fan speeds, the air-conditioning system exits the oil return mode. The compressor frequency f and the opening degree nv of the electronic expansion valve enter the PID control for refrigeration temperature control, while the internal and external fan speeds enter the speed control. According to the detected operating parameters, the refrigerant flow rate Mr, refrigeration capacity Q, and exhaust temperature of the air conditioner are calculated in real time. According to the calculated refrigeration capacity Q of the air-conditioning system, substituting it into the relationship model between the internal fan and the refrigeration capacity of the air conditioner, and the relationship model between the external fan and the refrigeration capacity of the air conditioner, the internal and external fan speeds corresponding to the load can be obtained.

[0127] Adjust the compressor frequency according to the difference between the real-time detected indoor environmental temperature and the set temperature and the change rate of the difference between the corresponding indoor environmental temperature and the set temperature. Perform PID control on the opening degree of the throttling device according to the exhaust temperature of the compressor and the target exhaust temperature. When the indoor temperature T ain and the set temperature T set the absolute value of the difference is less than or equal to the preset temperature value x (|T ain -T set | ≤ x), it is determined that the air conditioner enters a stable state, and the steps of the method of the present invention are returned to be executed again. Otherwise, continue to control the internal and external fan speeds and / or continue to perform PID control on the compressor frequency and the opening degree of the throttling device.

[0128] The present invention also provides a control device for an air conditioner.

[0129] Figure 6 It is a structural block diagram of an embodiment of the control device for an air conditioner provided by the present invention. As Figure 6 shown, the control device 100 includes: a judgment unit 110, a control unit 120, and a determination unit 130.

[0130] The judgment unit 110 is used to judge whether the air conditioner is in the free operation mode after the air conditioner is started and operated in the refrigeration mode. The free operation mode is a mode of operating without a set wind gear.

[0131] Specifically, after the air conditioner receives an instruction to start and operate in the refrigeration mode, it judges whether it is in the free operation mode. The free operation mode is specifically a mode of operating without a set wind gear, that is, the wind gear is not set, and the internal fan speed changes based on the change of the air conditioner operating state during the operation.

[0132] The control unit 120 is used to determine the initial operating parameters of the air conditioner if the judgment unit judges that the air conditioner is in the free operation mode, and control the air conditioner to operate according to the determined initial operating parameters.

[0133] Specifically, indoor and outdoor environmental parameters are detected, and based on these parameters and the air conditioner's settings, the initial operating parameters of the air conditioner are determined. These indoor and outdoor environmental parameters may specifically include: indoor ambient temperature (specifically, the indoor return air dry-bulb temperature) T. ain and outdoor ambient temperature T aout The setting parameters may specifically include: setting temperature T. set Specifically, after the air conditioner is turned on for cooling, the indoor fan is first started. With the indoor fan running, the initial operating parameters of the air conditioner are determined. That is, with the indoor fan running, indoor and outdoor environmental parameters are detected, and the initial operating parameters are determined based on the detected indoor and outdoor environmental parameters and the air conditioner's set parameters. Starting the indoor fan prevents inaccurate detection of environmental parameters due to uneven indoor temperature fields. The air conditioner's temperature sensor readings are affected by various factors such as installation location and indoor temperature field distribution. Starting the indoor fan makes the temperature more uniform and the detection more accurate. The indoor fan can be started at the set indoor fan speed of the ventilation mode (i.e., the default indoor fan speed of the ventilation mode).

[0134] Preferably, after the control unit 120 starts the internal fan at its initial speed, it compares the detected indoor ambient temperature (e.g., indoor dry-bulb temperature T) with the ambient temperature. ain ) and set temperature T set The size of T ain -T set When T ≤ a (a≤0℃), it means the indoor ambient temperature is lower than the user-set temperature. In this case, the compressor does not need to be turned on; the outdoor fan and compressor will not start, and only ventilation mode will operate. ain -T set When >a, the initial operating parameters of the air conditioner are determined based on the detected indoor and outdoor environmental parameters and the setting parameters of the air conditioner.

[0135] In one specific embodiment, the control unit 120 determines the set temperature T. set With indoor ambient temperature T ain Temperature difference ΔT1=T ain -T set and / or outdoor ambient temperature T aout With indoor ambient temperature T ain Temperature difference ΔT2=T aout -T ain The initial operating parameters of the air conditioner are determined.

[0136] Specifically, different set temperatures T set With indoor ambient temperature T ain Temperature difference ΔT1=T ain -T set and / or outdoor ambient temperature Taout With indoor ambient temperature T ain Temperature difference ΔT2=T aout -T ain The preset temperature T can be set according to different initial operating parameters. set With indoor ambient temperature T ain Temperature difference ΔT1=T ain -T set and / or outdoor ambient temperature T aout With indoor ambient temperature T ain Temperature difference ΔT2=T aout -T ain The correspondence with the initial operating parameters of the air conditioner (e.g., setting different set temperatures T). set With indoor ambient temperature T ain Temperature difference range and / or outdoor ambient temperature T aout With indoor ambient temperature T ain The temperature difference range corresponds to the initial operating parameters of the air conditioner, based on the set temperature T. set With indoor ambient temperature T ain Temperature difference ΔT1=T ain -T set and / or outdoor ambient temperature T aout With indoor ambient temperature T ain Temperature difference ΔT2=T aout -T ain To find the correspondence between the measured indoor ambient temperature T and the initial operating parameters of the air conditioner. ain and / or outdoor ambient temperature T aout The corresponding initial operating parameters of the air conditioner.

[0137] The initial operating parameters may specifically include: compressor initial frequency f, and internal fan initial speed N. o Initial speed of external fan N i And the initial opening degree n of the throttling device (electronic expansion valve) v At least one of them. The initial opening degree of the throttling device is determined based on the compressor frequency.

[0138] Based on the detected indoor and outdoor environmental parameters and the air conditioner's set parameters, the initial operating parameters of the air conditioner are determined, and the air conditioner is controlled to operate according to these initial operating parameters. Among these, the initial speed N of the outdoor fan is... i Upon startup, the compressor starts running at its initial frequency f, and the internal fan starts running at its initial speed N. o The operating, throttling device (electronic expansion valve) is set at an initial opening n. v run.

[0139] Preferably, the control unit 120 first controls the air conditioner to enter the oil return mode. Based on the determined initial compressor frequency and the set oil return frequency, it controls the air conditioner's compressor to operate at either the initial compressor frequency or the set oil return frequency. It also controls the indoor and outdoor fans to operate at their determined initial speeds, and controls the opening of the air conditioner's throttling device (electronic expansion valve) based on the oil return frequency during oil return. Different oil return frequencies correspond to different initial openings of the throttling device. Specifically, when the determined initial compressor frequency f is greater than the set oil return frequency, the compressor is controlled to start operating at the initial compressor frequency; when the initial compressor frequency f is less than the set oil return frequency, the compressor is controlled to start operating at the set oil return frequency. After controlling the air conditioner to operate according to the determined initial operating parameters for a first preset time, the control unit 120 exits the oil return mode.

[0140] The determining unit 130 is used to determine the cooling capacity of the air conditioner based on the operating status parameters of the air conditioner after the control unit controls the air conditioner to run for a first preset time according to the determined initial operating parameters.

[0141] Specifically, after the control unit 120 controls the air conditioner to run for a first preset time according to the determined initial operating parameters (for example, entering the oil return mode and running for a first preset time before exiting the oil return mode), the cooling capacity of the air conditioner is calculated based on the compressor frequency and the operating status parameters of the air conditioner. Based on the calculated cooling capacity, the speed of the indoor fan and / or the outdoor fan of the air conditioner is controlled. The operating status parameters may specifically include: compressor frequency f, evaporator tube temperature (specifically, the temperature within the evaporator tubes) T. e, 1. Condenser tube temperature (specifically, the temperature inside the condenser tubes) T c Condenser outlet temperature T C,out and exhaust temperature T dis At least one of them.

[0142] Figure 2 A flowchart illustrating a specific implementation of a determining unit determining the cooling capacity of the air conditioner based on its operating status parameters is shown.

[0143] like Figure 2 As shown, the cooling capacity of the air conditioner can be calculated based on the operating status parameters of the air conditioner, following these steps:

[0144] Step S131, based on the compressor frequency f and evaporator tube temperature T e and the saturation temperature drop dT from the middle of the evaporator to the compressor suction port sat,e Calculate the intake saturation temperature T sucsat.

[0145] In one specific implementation, the saturation temperature drop dT from the middle of the evaporator to the compressor suction port can be calculated using the following fitted relationship. sat,e :

[0146] dT sat,e =f(f)=(C0+C1f+C2f) 2 )

[0147] In one specific implementation, the compressor frequency f and the evaporator tube temperature T can be used as the basis. e The intake saturation temperature T is calculated using the following fitted relationship. sucsat :

[0148] T sucsat =f(T) e f) = T e -(C0+C1f+C2f) 2 )

[0149] Among them, T sucsat dT is the intake saturation temperature (°C), f is the compressor frequency (Hz), and dT is the compressor frequency. sat,e T represents the saturation temperature drop from the middle of the evaporator to the compressor suction port (unit: °C). e C0, C1, and C2 are the evaporator tube temperature (unit: °C), and the values ​​of the same fitting coefficients in different fitting formulas in this invention are different.

[0150] Step S132, based on the compressor frequency f and the suction saturation temperature T sucsat Exhaust temperature T dis and the temperature T in the condenser tube c Calculate the inhaled dryness fraction x suc .

[0151] In one specific implementation, the inspiratory dryness fraction x can be calculated using the following fitting formula. suc :

[0152] x suc =f(f,T) sucsat T C T dis )=C0+C1f+C2T sucsat +C3T c +C4T dis

[0153] Where f is the compressor operating frequency (unit: Hz), T sucsat T is the intake saturation temperature (°C). c T represents the temperature inside the condenser tubes (unit: °C). disWhere is the exhaust temperature (°C), and C0, C1, C2, C3, and C4 are fitting coefficients. In this invention, the values ​​of the same fitting coefficients in different fitting formulas are different.

[0154] Step S133, based on the calculated inhalation dryness x suc The size of the superheated gas absorbance specific volume v is calculated. suc Or two-phase intake specific volume v suc .

[0155] Among them, if the inhalation dryness x suc If the value is greater than or equal to 1, then calculate the superheated gas absorption specific volume v. suc If the inhalation dryness is x suc If the value is less than 1, then calculate the two-phase intake specific volume v. suc .

[0156] Specifically, if the inhalation is overheated, i.e., the inhalation dryness is x suc If the value is greater than or equal to 1, then based on the compressor frequency f and the suction saturation temperature T... sucsat Exhaust temperature T dis and the temperature T in the condenser tube c Calculate the intake superheat ΔT sucsh According to the intake superheat ΔT sucsh Intake saturation temperature T sucsat and inspiratory saturation specific volume v sucgsat Calculate the superheated gas specific volume v suc .

[0157] In one specific implementation, the intake superheat ΔT can be calculated using the following fitted relationship. sucsh :

[0158] ΔT sucsh =f(f,T) sucsat T C T dis )=C0+C1f+C2T sucsat +C3T c +C4T dis ;

[0159] Where f is the compressor operating frequency, T sucsat T is the intake saturation temperature. c T represents the temperature inside the condenser tubes. dis Where C is the exhaust temperature, and C0, C1, C2, C3, and C4 are fitting coefficients. In this invention, the values ​​of the same fitting coefficients in different fitting equations are different.

[0160] In one specific implementation, the superheated gas absorption specific volume v can be calculated using the following fitting relationship. suc (Unit: m) 3 / kg):

[0161] v suc =f(T) sucsat ΔT sucsh v sucgsat )=(C0+C1T sucsat +C2ΔT sucsh )×v sucgsat

[0162] Among them, v sucgsat Specific volume of saturated inhaled gas, unit: m³ 3 / kg, depending on the inhalation saturation temperature T sucsat Calculate using the following fitted relationship:

[0163] v sucgsat =f(T) sucsat )=1 / (C0+C1T sucsat +C2T sucsat +C3T sucsat );

[0164] Wherein, C0, C1, C2, and C3 are fitting coefficients, and the values ​​of the same fitting coefficients in different fitting formulas in this invention are different.

[0165] If the inhaled air contains liquid, i.e., the inhaled dryness is x suc If it is less than 1, then it is based on the inhalation dryness x suc Specific volume of inhaled saturated gas v sucgsat Specific volume v of saturated uptake liquid suclsat Calculate the two-phase intake specific volume v suc C0, C1, and C2 are fitting coefficients. In this invention, the values ​​of the same fitting coefficients in different fitting relationships are different.

[0166] In one specific implementation, the two-phase absorbance specific volume (unit: m³) can be calculated using the following fitting formula. 3 / kg):

[0167] v suc =f(x) suc v suclsat v sucgsat )=(1-x suc )v suclsat +x suc v sucgsat )

[0168] Among them, v suclsat Specific volume of the saturated absorbent liquid, unit: m³ 3 / kg, depending on the inhalation saturation temperature T sucsat Calculate using the following fitted relationship:

[0169] v suclsat =f(T) sucsat)=1 / (C0+C1T sucsat +C2T sucsat );

[0170] Wherein, C0, C1, and C2 are fitting coefficients, and the values ​​of the same fitting coefficients in different fitting relationships in this invention are different.

[0171] Step S134, based on the compressor frequency f and condenser tube temperature T c and evaporator tube temperature T e Calculate the compressor volumetric efficiency η v .

[0172] In one specific implementation, the compressor volumetric efficiency η can be calculated using the following fitted relationship. v :

[0173] η v =f(f,T) C T e )=C0+C1f+C2T c +C3T e

[0174] Wherein, C0, C1, and C2 are fitting coefficients, and the values ​​of the same fitting coefficients in different fitting relationships in this invention are different.

[0175] Step S135, based on the superheated intake specific volume v suc Or two-phase intake specific volume v suc Combined with compressor cylinder volume V rev Compressor frequency f and compressor volumetric efficiency η v Calculate the circulating refrigerant flow rate M in the system. r .

[0176] Specifically, if the inhalation dryness x suc Greater than or equal to 1, based on the compressor cylinder volume V rev (Preset value), Superheated intake specific volume v suc Compressor frequency f and compressor volumetric efficiency η v Calculate the circulating refrigerant flow rate M in the system. r If the inhalation dryness is x suc Less than 1, based on the compressor cylinder volume V rev Two-phase intake specific volume v suc Compressor frequency f and compressor volumetric efficiency η v Calculate the circulating refrigerant flow rate M in the system. r .

[0177] In one specific implementation, the circulating refrigerant flow rate M in the system can be calculated using the following fitted relationship. r :

[0178] M r =f(V rev v suc , f, η v ) = V rev / v suc ×f×η v

[0179] Since the compressor frequency is measured in revolutions per second (rpm), while the flow rate is measured in kg / h, it needs to be multiplied by 3600 to convert it to hours, i.e., M. r =V rev / v suc ×f×η v ×3600.

[0180] Step S136, based on the calculated circulating refrigerant flow rate M in the system r Inhalation dryness x suc and inhalation saturation temperature T sucsat And the detected condenser outlet temperature T c_out Calculate the cooling capacity Q of the air conditioner.

[0181] First, based on the condenser outlet temperature T c_out Calculate the specific enthalpy h at the condenser outlet of the refrigeration system. c_out (Unit: kJ / kg). In one specific embodiment, the condenser outlet temperature T can be used as a reference. c_out The condenser outlet specific enthalpy h of the refrigeration system is calculated using the following fitted relationship. c_out :

[0182] h c_out =f(T) C_out )=C0+C1T c_out +C2T 2 c_out +C3T 3 c_out

[0183] Wherein, C0, C1, C2, and C3 are fitting coefficients, and the values ​​of the same fitting coefficients in different fitting formulas in this invention are different.

[0184] Then, based on the inhalation saturation temperature T sucsat Calculate the saturated intake enthalpy h sucgsat (Unit: kJ / kg) and enthalpy of saturated liquid absorption ratio (h) suclsat (Unit: kJ / kg);

[0185] In one specific implementation, the intake saturation temperature T can be used as a reference. sucsat The saturated uptake ratio enthalpy h is calculated using the following fitted relationship. sucgsat :

[0186] h sucgsat =f(T) sucsat )=C0+C1T sucsat +C2T 2 sucsat +C3T 3 sucsat

[0187] Wherein, C0, C1, C2, and C3 are fitting coefficients, and the values ​​of the same fitting coefficients in different fitting formulas in this invention are different.

[0188] In one specific implementation, the intake saturation temperature T can be used as a reference. sucsat The saturated liquid uptake enthalpy h is calculated using the following fitted relationship. suclsat :

[0189] h suclsat =f(T) sucsat )C0+C1T sucsat +C2T 2 sucsat +C3T 3 sucsat

[0190] Wherein, C0, C1, C2, and C3 are fitting coefficients, and the values ​​of the same fitting coefficients in different fitting formulas in this invention are different.

[0191] Then, based on the inspiratory dryness x suc saturated inhalation enthalpy h sucgsat Enthalpy of saturated liquid absorption h suclsat Calculate the suction enthalpy h of the refrigeration system suc (Unit: kJ / kg). In one specific embodiment, the suction enthalpy h of the refrigeration system can be calculated using the following fitting formula. suc :

[0192] h suc =f(x) suc h suclsat h sucgsat )=(1-x suc )h suclsat +x suc h sucgsat

[0193] Finally, based on the calculated condenser outlet specific enthalpy h of the refrigeration system... c_out Enthalpy h of the suction gas of the refrigeration system suc Calculate the cooling capacity Q of the air conditioner, that is, the cooling ability Q (unit: W):

[0194] Q = M r ×(h suc -h c_out) / 3.6

[0195] The cooling capacity of the air conditioner, i.e., the cooling volume Q, can be calculated by following the steps described above.

[0196] The control unit 120 is further configured to: control the speed of the indoor fan and / or the speed of the outdoor fan of the air conditioner according to the cooling capacity of the air conditioner determined by the determining unit 130.

[0197] Specifically, the control unit 120 calculates the indoor fan speed corresponding to the cooling capacity according to a preset relationship model between cooling capacity and indoor fan speed, and / or calculates the outdoor fan speed corresponding to the cooling capacity according to a preset relationship model between cooling capacity and outdoor fan speed; it controls the indoor fan of the air conditioner to operate at the calculated indoor fan speed, and / or controls the outdoor fan of the air conditioner to operate at the calculated outdoor fan speed. The calculated cooling capacity of the air conditioner is then substituted into the preset relationship model between cooling capacity and indoor and / or outdoor fan speeds to calculate the indoor fan speed and / or outdoor fan speed corresponding to the cooling capacity of the air conditioner.

[0198] The cooling capacity Q and the internal fan speed N i The relational model can specifically be:

[0199] N i =f(Q)=C0+C1*Q;

[0200] The cooling capacity and the external fan speed N o The relational model body can specifically be:

[0201] N o =f(Q)=C0+C1*Q;

[0202] Wherein, C0 and C1 are fitting coefficients, and the values ​​of the same fitting coefficients in different fitting relationships in this invention are different.

[0203] Based on the calculated cooling capacity Q of the air conditioner, the optimal indoor and outdoor fan speeds Ni and No can be obtained according to the above relationship model.

[0204] The cooling capacity Q of the air conditioner is calculated in real time, and the corresponding indoor and outdoor fan speeds Ni and No are obtained according to the relationship model based on the calculated cooling capacity. The indoor and outdoor fans are controlled according to the calculated indoor and outdoor fan speeds Ni and No.

[0205] Preferably, the average value Q of the cooling capacity of the air conditioner is calculated every third preset time interval (within the first third preset time interval). ave Based on the calculated average value Q of the cooling capacity aveThe corresponding internal and external fan speeds Ni and No are calculated according to the relational model, and the internal and external fans are controlled according to the calculated speeds Ni and No. The control process for the internal and external fans described above can be referenced. Figure 3 As shown.

[0206] Optionally, the control unit 120 is further configured to: perform PID control on the compressor frequency and throttling device opening of the air conditioner after controlling the air conditioner to run for a first preset time according to the determined initial operating parameters.

[0207] Specifically, after controlling the air conditioner to run for a first preset time according to the determined initial operating parameters, the oil return mode is exited, and the compressor frequency and throttling device opening of the air conditioner are controlled by PID.

[0208] In one specific embodiment, the control unit 120 performs PID control on the compressor frequency f of the air conditioner based on the indoor ambient temperature and the set temperature of the air conditioner. Specifically, based on the real-time detected indoor ambient temperature (indoor dry-bulb temperature) T... ain With the set temperature T set The difference ΔT ain (ΔT ain =T ain -T ain_set And the corresponding rate of change δT of the difference between the indoor ambient temperature and the set temperature. ain (δT ain =ΔT ain(n) -ΔT ain(n-1) Adjust the compressor frequency.

[0209] More specifically, for the compressor frequency f, the indoor ambient temperature T is detected in real time every second preset time interval. ain With the set temperature T set The difference ΔT ain (ΔT ain =T ain -T ain_set And the corresponding rate of change δT of the difference between the indoor ambient temperature and the set temperature. ain (δT ain =ΔT ain(n) -ΔT ain(n-1) Every third preset time interval (the third preset time interval is an integer multiple of the second preset time interval), calculate the indoor ambient temperature T (within the first third preset time interval). ain With the set temperature T set Difference ΔT ain The average value (ΔT) ain_ave ={T ain -T ain_set}) and the average rate of change δT of the difference between the indoor ambient temperature and the set temperature. ain (δT ain_ave ={ΔT ain(n) -ΔT ain(n-1) According to the calculated indoor ambient temperature T ain With the set temperature T set Difference ΔT ain The average value ΔT ain_ave And the average rate of change δT of the difference between the indoor ambient temperature and the set temperature. ain_ave The compressor frequency f is adjusted, where the adjustment amount of the compressor frequency is δf = k f1 ×ΔT ain_ave +k f2 ×δT ain_ave , where k f1 and k f2 It is a constant and can be obtained experimentally.

[0210] In one specific embodiment, the control unit 120 performs PID control on the air conditioner and the throttling device opening degree nv based on the air conditioner's compressor exhaust temperature and target exhaust temperature. Specifically, it uses the difference between the real-time detected exhaust temperature Tdis and the target exhaust temperature Tdis_tar, and the rate of change δT of the difference between the exhaust temperature and the target exhaust temperature. dis_tar (δT dis_tar =ΔT dis_tar (n)-ΔT dis_tar (n-1)) Adjust the opening degree nv of the throttling device (electronic expansion valve).

[0211] More specifically, for the electronic expansion valve opening degree nv, the exhaust temperature T is detected in real time every second preset time interval. dis With the target exhaust temperature T dis_ta The difference ΔT of r dis_tar and the rate of change δT of the difference between the exhaust temperature and the target exhaust temperature. dis_tar (δT dis_tar =ΔT dis_tar (n)-ΔT dis_tar (n-1)); Every third preset time interval (the third preset time interval is an integer multiple of the second preset time interval), calculate the exhaust temperature T (within the first third preset time interval). dis With the target exhaust temperature T dis_tar The difference (ΔT) dis =T dis -T dis_tar The average value ΔT dis_ave (ΔT dis_ave ={T dis -T dis_tar}, and the average change rate δT of the difference between the corresponding exhaust gas temperature and the target exhaust gas temperature dis_ave (δT dis_ave ={ΔT dis (n)-ΔT dis (n - 1)}, and the throttle device (such as an electronic expansion valve) opening adjustment amount δnv = k nv1 ×ΔT dis_ave +k nv2 ×δT dis_ave , where k nv1 and k nv2 are constants and can be obtained through experiments.

[0212] After performing PID control on the compressor frequency and throttle device opening of the air conditioner, it is judged whether the absolute value |ΔTain| of the difference between the indoor temperature and the set temperature is less than or equal to the preset difference threshold corresponding to the corresponding operating parameters (that is, different preset difference thresholds correspond to the compressor frequency and throttle device opening. For example, the preset difference threshold corresponding to the compressor frequency is x, and the preset difference threshold corresponding to the throttle device opening is z). If so, the current operating parameters are maintained. If not, PID control continues.

[0213] The process of the above control unit 120 performing PID control on the compressor frequency and throttle device opening can also be referred to Figure 3 as shown.

[0214] When the absolute value of the difference between the indoor temperature T ain and the set temperature T set is less than or equal to the preset temperature value x (|T ain -T set |≤x), it is determined that the air conditioner enters a stable state, and the steps of the method of the present invention are returned to be executed again. Otherwise, the control of the internal and external fan speeds continues and / or the PID control of the compressor frequency and throttle device opening continues.

[0215] The present invention also provides a storage medium corresponding to the control method of the air conditioner, on which a computer program is stored, and when the computer program is executed by a processor, the steps of any of the foregoing methods are implemented.

[0216] The present invention also provides an air conditioner corresponding to the control method of the air conditioner, including a processor, a memory, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, the steps of any of the foregoing methods are implemented.

[0217] The present invention also provides an air conditioner corresponding to the control device of the air conditioner, including any of the foregoing control devices.

[0218] The present invention also provides a computer program product corresponding to the control method of the air conditioner, including a computer program that, when executed by a processor, implements the steps of any of the aforementioned methods.

[0219] Accordingly, the solution provided by the present invention determines the cooling capacity of the air conditioner based on the operating status parameters of the air conditioner when the air conditioner is in free operation mode, and controls the speed of the indoor fan and / or the speed of the outdoor fan of the air conditioner based on the cooling capacity of the air conditioner. This can avoid the problem of low energy efficiency caused by the mismatch between the indoor and outdoor fans and the load when the air conditioning system is in free operation, and make the air conditioner always operate in the optimal energy efficiency state.

[0220] The solution provided by this invention can dynamically adjust the speed of the indoor and outdoor fans according to the cooling capacity of the air conditioner, so that the air conditioning system can operate efficiently and stably near the optimal state point under any operating condition, thereby reducing system energy consumption.

[0221] The solution provided by this invention can calculate the air conditioning capacity in real time based on the building load according to the detected air conditioning operating status parameters, and the accuracy is high.

[0222] The solution provided by this invention uses an optimized air conditioning load model to calculate the air conditioning load, dynamically adjust the speed of the indoor and outdoor fans, balance the system energy efficiency, and enable the system to converge quickly. The opening of the electronic expansion valve is automatically adjusted according to the exhaust superheat, so that the air conditioner always operates near the optimal state point. This satisfies the reliability and stability of the system operation while saving energy and being highly efficient. It can also shorten the control operation time and ensure stable operation.

[0223] The functions described herein can be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions can be stored as one or more instructions or codes on or transmitted via a computer-readable medium. Other examples and embodiments are within the scope and spirit of this invention and the appended claims. For example, due to the nature of software, the functions described above can be implemented using software executed by a processor, hardware, firmware, hardwired, or any combination thereof. Furthermore, the functional units can be integrated into a single processing unit, or each unit can exist physically separately, or two or more units can be integrated into a single unit.

[0224] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only schematic. For example, the division of the units can be a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0225] The units described as separate components may or may not be physically separate. Similarly, the components of the control device may or may not be physical units; they may be located in one place or distributed across multiple units. Some or all of the units can be selected to achieve the purpose of this embodiment, depending on actual needs.

[0226] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to related technologies, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0227] The above description is merely an embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A method for controlling an air conditioner, characterized in that, include: After the air conditioner starts cooling, it is determined whether the air conditioner is in free operation mode, which is an operation mode without a set fan speed. If it is determined that the air conditioner is in free operation mode, then the initial operating parameters of the air conditioner are determined, and the air conditioner is controlled to operate according to the determined initial operating parameters; After controlling the air conditioner to run for a first preset time according to the determined initial operating parameters, the cooling capacity of the air conditioner is determined according to the operating status parameters of the air conditioner; Based on the determined cooling capacity of the air conditioner, control the speed of the indoor fan and / or the speed of the outdoor fan of the air conditioner.

2. The method according to claim 1, characterized in that, Also includes: After the air conditioner is turned on for cooling, if it is determined that the air conditioner is in free operation mode, the indoor fan of the air conditioner is started first. When the indoor fan is started, the initial operating parameters of the air conditioner are determined.

3. The method according to claim 1 or 2, characterized in that, The initial operating parameters include at least one of the following: compressor initial frequency, internal fan initial speed, external fan initial speed, and throttling device initial opening degree; Controlling the air conditioner to operate according to the determined initial operating parameters includes: The air conditioner is controlled to enter the oil return mode, and the oil return frequency is set according to the determined initial frequency of the compressor and the set oil return frequency. The compressor of the air conditioner is controlled to operate at the initial compressor frequency or at the set oil return frequency; The indoor and outdoor fans of the air conditioner are controlled to operate at determined initial speeds for the indoor and outdoor fans, respectively. The opening degree of the throttling device of the air conditioner is controlled according to the oil return frequency of the compressor during oil return.

4. The method according to claim 1 or 2, characterized in that, The operating status parameters include at least one of the following: evaporator tube temperature, condenser tube temperature, condenser outlet temperature, and exhaust temperature; Determining the cooling capacity of the air conditioner based on its operating status parameters includes: Calculate the suction saturation temperature based on the compressor frequency, evaporator tube temperature, and saturation pressure drop from the middle of the evaporator to the compressor suction port. Calculate the suction dryness based on the compressor frequency, suction saturation temperature, discharge temperature, and condenser tube temperature; Calculate the superheated specific volume or two-phase specific volume of the intake based on the calculated intake dryness. The compressor volumetric efficiency is calculated based on the compressor frequency, condenser tube temperature, and evaporator tube temperature. Calculate the circulating refrigerant flow rate in the system based on the superheated suction specific volume or two-phase suction specific volume, combined with the compressor cylinder volume, compressor frequency, and compressor volumetric efficiency. The cooling capacity of the air conditioner is calculated based on the system's circulating refrigerant flow rate, suction dryness, suction saturation temperature, and the detected condenser outlet temperature.

5. The method according to claim 1 or 2, characterized in that, Based on the determined cooling capacity of the air conditioner, controlling the speed of the indoor fan and / or the speed of the outdoor fan of the air conditioner includes: Calculate the internal fan speed corresponding to the cooling capacity according to the preset relationship model between cooling capacity and internal fan speed, and / or calculate the external fan speed corresponding to the cooling capacity according to the preset relationship model between cooling capacity and external fan speed. Control the indoor fan of the air conditioner to operate at the calculated indoor fan speed, and / or control the outdoor fan of the air conditioner to operate at the calculated outdoor fan speed.

6. The method according to claim 1 or 2, characterized in that, Also includes: After controlling the air conditioner to operate according to the determined initial operating parameters for a first preset time, PID control is performed on the compressor frequency and throttling device opening of the air conditioner, including: The compressor frequency of the air conditioner is controlled by PID based on the indoor ambient temperature and the set temperature of the air conditioner. And / or, Based on the exhaust temperature of the air conditioner compressor and the target exhaust temperature, PID control is performed on the air conditioner and the opening degree of the throttling device.

7. The method according to claim 6, characterized in that, The compressor frequency of the air conditioner is controlled by PID based on the indoor ambient temperature and the set temperature of the air conditioner, including: The compressor frequency is adjusted based on the real-time difference between the indoor ambient temperature and the set temperature, and the corresponding rate of change of the difference between the indoor ambient temperature and the set temperature. And / or, Based on the compressor's exhaust temperature and the target exhaust temperature of the air conditioner, PID control is performed on the air conditioner and the opening degree of the throttling device, including: The opening of the throttling device is adjusted based on the difference between the real-time detected exhaust temperature and the target exhaust temperature, as well as the rate of change of the difference between the exhaust temperature and the target exhaust temperature.

8. A control device for an air conditioner, characterized in that, include: The judgment unit is used to determine whether the air conditioner is in free operation mode after the air conditioner is turned on and running in cooling mode. The free operation mode is the operation mode without a set fan speed. The control unit is configured to determine the initial operating parameters of the air conditioner and control the air conditioner to operate according to the determined initial operating parameters if the judgment unit determines that the air conditioner is in free operation mode. The determining unit is used to determine the cooling capacity of the air conditioner based on the operating status parameters of the air conditioner after the control unit controls the air conditioner to run for a first preset time according to the determined initial operating parameters; The control unit is further configured to: control the speed of the indoor fan and / or the speed of the outdoor fan of the air conditioner according to the cooling capacity of the air conditioner determined by the determining unit.

9. A storage medium, characterized in that, It stores a computer program that, when executed by a processor, implements the steps of the method according to any one of claims 1-7.

10. An air conditioner, characterized in that, It includes a processor, a memory, and a computer program stored in the memory that can run on the processor, wherein the processor executes the program to implement the steps of any of the methods of claims 1-7, or includes the control device as described in claim 8.

11. A computer program product, characterized in that, Includes a computer program that, when executed by a processor, implements the steps of the method according to any one of claims 1-7.

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