Control method and equipment of carbon dioxide heat pump water heater and storage medium

Abstract

The invention provides a control method and device for a carbon dioxide heat pump water heater and a storage medium. The method comprises the steps that the target pressure of carbon dioxide on a first loop is set for the heat pump water heater; the pressure in the first loop is greater than the critical pressure of the carbon dioxide; the target suction superheat degree is set for the heat pump water heater; calculating a pressure deviation value between the target pressure and the real-time pressure of the heat pump water heater; calculating an air suction superheat degree deviation value between the real-time air suction superheat degree of the heat pump water heater and the target air suction superheat degree; and cooperatively controlling a compressor and an electronic expansion valve in the heat pump water heater according to the pressure deviation value and the suction superheat degree deviation value. According to the embodiment of the invention, the compressor and the electronic expansion valve in the CO2 heat pump water heater are cooperatively controlled by combining the high-pressure superheat degree and the suction superheat degree, the high-pressure superheat degree and the suction superheat degree are decoupled, the compressor and the electronic expansion valve are decoupled, the control efficiency of the CO2 heat pump water heater is effectively improved, and efficient, stable and reliable operation of the CO2 heat pump water heater is kept.

Description

Technical Field

[0001] This invention belongs to the technical field of heat pumps, and in particular relates to a control method, equipment and storage medium for a carbon dioxide heat pump water heater. Background Technology

[0002] CO2 heat pump water heaters are energy-saving devices that use carbon dioxide (such as R744) as a natural refrigerant and efficiently transfer heat from a low-temperature environment to water through transcritical cycle technology, thereby producing high-temperature hot water (60℃-90℃).

[0003] CO2 heat pump water heaters typically use exhaust pressure (high pressure) as the feedback control target. By adjusting the opening of the electronic expansion valve, the high pressure is maintained at the set optimal high pressure value.

[0004] However, high pressure is coupled with other performance parameters in CO2 heat pump water heaters. Optimizing high pressure affects other performance parameters in CO2 heat pump water heaters, thereby impacting the operating efficiency of CO2 heat pump water heaters. Summary of the Invention

[0005] In view of this, the present invention provides a control method, device and storage medium for a carbon dioxide heat pump water heater, so as to improve the operating efficiency of the carbon dioxide heat pump water heater.

[0006] The first aspect of the present invention provides a control method for a carbon dioxide heat pump water heater, comprising: Set a target pressure for carbon dioxide in the first circuit of the heat pump water heater; the pressure in the first circuit is greater than the critical pressure of carbon dioxide. Set a target intake superheat for the heat pump water heater; Calculate the pressure deviation between the target pressure and the real-time pressure of the heat pump water heater; Calculate the suction superheat deviation between the real-time suction superheat of the heat pump water heater and the target suction superheat; The compressor and electronic expansion valve in the heat pump water heater are controlled in coordination based on the pressure deviation value and the intake superheat deviation value.

[0007] A second aspect of the present invention provides a control device for a carbon dioxide heat pump water heater, comprising: The target pressure setting module is used to set the target pressure of carbon dioxide in the first circuit of the heat pump water heater; the pressure in the first circuit is greater than the critical pressure of carbon dioxide. The target intake superheat setting module is used to set the target intake superheat for the heat pump water heater. The pressure deviation calculation module is used to calculate the pressure deviation between the target pressure and the real-time pressure of the heat pump water heater. The intake superheat deviation calculation module is used to calculate the intake superheat deviation between the real-time intake superheat of the heat pump water heater and the target intake superheat. The collaborative control module is used to collaboratively control the compressor and electronic expansion valve in the heat pump water heater based on the pressure deviation value and the suction superheat deviation value.

[0008] A third aspect of the present invention provides an electronic device including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the computer program, implements the control method for a carbon dioxide heat pump water heater as described in the first aspect above.

[0009] A fourth aspect of the present invention provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the control method for a carbon dioxide heat pump water heater as described in the first aspect above.

[0010] The fifth aspect of the present invention provides a computer program product that, when run on a computer, causes the computer to perform the control method for a carbon dioxide heat pump water heater as described in the first aspect above.

[0011] Compared with the prior art, the embodiments of the present invention have the following beneficial effects: In this embodiment, a target pressure for carbon dioxide in the first loop of the heat pump water heater is set; the pressure in the first loop is greater than the critical pressure of carbon dioxide; a target suction superheat is set for the heat pump water heater; the pressure deviation between the target pressure and the real-time pressure of the heat pump water heater is calculated; the suction superheat deviation between the real-time suction superheat and the target suction superheat is calculated; and the compressor and electronic expansion valve in the heat pump water heater are controlled collaboratively based on the pressure deviation and suction superheat deviation. This embodiment combines high pressure and suction superheat to collaboratively control the compressor and electronic expansion valve in the CO2 heat pump water heater, decoupling the high pressure and suction superheat, and decoupling the compressor and electronic expansion valve, effectively improving the control efficiency of the CO2 heat pump water heater and maintaining its efficient, stable, and reliable operation. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1This is a schematic diagram of a control method for a carbon dioxide heat pump water heater provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of a CO2 heat pump water heater provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of a control device for a carbon dioxide heat pump water heater provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of an electronic device provided in an embodiment of the present invention. Detailed Implementation

[0014] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the present invention. However, those skilled in the art will recognize that the present application may be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted to avoid unnecessary detail that could obscure the description of the present application.

[0015] The technical solution of the present invention will be illustrated below through specific embodiments.

[0016] Reference Figure 1 The diagram illustrates a control method for a carbon dioxide heat pump water heater according to an embodiment of the present invention, which may specifically include the following steps: Step 101: Set the target pressure of carbon dioxide in the first circuit of the heat pump water heater.

[0017] CO2 heat pump water heaters have a unique transcritical circulation system, which utilizes the characteristics of CO2's low critical temperature (31.1℃) and high critical pressure (7.38MPa) to achieve transcritical circulation.

[0018] Under normal circumstances, such as Figure 2 As shown, a CO2 heat pump water heater includes components such as a compressor, gas cooler, evaporator, throttling device, pressurized water tank, and control system.

[0019] The compressor provides circulating power to compress CO2, the gas cooler exchanges heat between CO2 and water to release heat, the evaporator exchanges heat between CO2 and air to absorb heat, the throttling device precisely controls the pressure and temperature reduction of CO2, the pressurized water tank stores high-temperature hot water, and the control system monitors and adjusts operating parameters in real time.

[0020] For example, the transcritical cycle of a CO2 heat pump water heater includes the following processes: 1. Compression process The compressor draws in low-temperature, low-pressure gaseous CO2 and compresses it into high-temperature, high-pressure supercritical CO2 (pressure can reach 10-15 MPa).

[0021] 2. Exothermic process Supercritical CO2 enters the gas cooler, releasing a large amount of heat to the water through sensible heat transfer, causing the water temperature to rise rapidly. 3. Throttling process After being depressurized and cooled by the expansion valve / throttle valve, it becomes a low-temperature, low-pressure gas-liquid two-phase mixture. 4. Heat absorption process It absorbs heat from the air in the evaporator, evaporates completely into gaseous CO2, and returns to the compressor to complete the cycle.

[0022] In the transcritical circulation system of a CO2 heat pump water heater, the first loop and the second loop are divided to distinguish between high pressure and low pressure. High pressure and low pressure refer to the CO2 fluid pressure in two key sections of the circulation loop. With the compressor as the core dividing point, they correspond to the pressure states of the supercritical region and the subcritical region, respectively.

[0023] Therefore, the pressure in the first loop is greater than the critical pressure of carbon dioxide, i.e., high pressure, while the pressure in the second loop is less than the critical pressure of carbon dioxide, i.e., low pressure.

[0024] Furthermore, high pressure can refer to the CO2 pressure in the first loop, from the compressor exhaust port and gas cooler to the inlet of the throttling device, which is the highest pressure section in a CO2 heat pump water heater. Since the critical pressure of CO2 is 7.38 MPa, the high-pressure side pressure is usually higher than the critical pressure (8.5-15 MPa). At this time, CO2 is in a supercritical state (without gas-liquid two-phase distinction).

[0025] Low pressure refers to the CO2 pressure in the second loop, from the outlet of the throttling device and the evaporator to the compressor suction port. It is the lowest pressure section in a CO2 heat pump water heater. The pressure on the low-pressure side is always lower than the CO2 critical pressure (2-4 MPa). In this section, CO2 is in a gas-liquid two-phase mixed state or a gaseous state, which belongs to the subcritical region.

[0026] The higher the pressure, the more sensible heat supercritical CO2 releases in the gas cooler, and the faster the water heats up. CO2 heat pump water heaters have an optimal high pressure. Too high a pressure will cause the compressor power consumption to increase dramatically, while too low a pressure will result in insufficient heat exchange temperature difference. Both will reduce energy efficiency.

[0027] In this embodiment, the target pressure P_opt (in MPa) of CO2 in the first circuit of the CO2 heat pump water heater can be set as the optimal high pressure according to the operating conditions of the CO2 heat pump water heater.

[0028] In a practical implementation, the outlet water temperature T_gc_out (in °C) of the gas cooler in the first loop of the heat pump water heater can be detected, and the evaporation temperature T_evap (in °C) of carbon dioxide in the second loop of the heat pump water heater can be calculated.

[0029] Among them, low pressure corresponds to the evaporation pressure of CO2. The lower the pressure, the lower the evaporation temperature (e.g., 2MPa corresponds to an evaporation temperature of about -10℃). The evaporator is more likely to absorb heat from the low-temperature environment. The evaporation temperature T_evap can be obtained by looking up the CO2 saturation temperature table based on the measurement value of the low-pressure sensor.

[0030] The outlet water temperature T_gc_out and the evaporation temperature T_evap are combined in a linear or nonlinear manner to form the target carbon dioxide pressure P_opt of the heat pump water heater in the first loop.

[0031] Among them, the target pressure P_opt is positively correlated with the outlet water temperature T_gc_out and the evaporation temperature T_evap.

[0032] For example, the product of the outlet water temperature T_gc_out and the preset first fusion coefficient k1, the product of the evaporation temperature T_evap and the preset second fusion coefficient k2, and the preset reference value C are added together to obtain the target pressure P_opt of carbon dioxide in the first loop of the heat pump water heater.

[0033] In this example, the target pressure P_opt of carbon dioxide in the first loop of the heat pump water heater can be expressed as: P_opt=k1×T_gc_out+k2×T_evap + C, where k1=0.07 (MPa / ℃), k2=0.06 (MPa / ℃), and C=6.5.

[0034] Under normal circumstances, the optimal high pressure varies significantly with the outlet water temperature T_gc_out and the evaporation temperature T_evap. Setting the target pressure P_opt of the CO2 heat pump water heater based on the outlet water temperature T_gc_out and the evaporation temperature T_evap can effectively improve the adaptability of the operating conditions and help the CO2 heat pump water heater operate efficiently under all operating conditions.

[0035] Step 102: Set the target intake superheat for the heat pump water heater.

[0036] Because CO2 refrigerant has a large latent heat and high thermal conductivity, its superheat control is more sensitive. Therefore, the target suction superheat SH_set setting range for CO2 heat pump water heaters is relatively narrow, generally between 3℃ and 8℃.

[0037] In practical applications, the target intake superheat SH_set can be set for the CO2 heat pump water heater based on its operating conditions (such as ambient temperature, water temperature, etc.).

[0038] Step 103: Calculate the pressure deviation between the target pressure and the real-time pressure of the heat pump water heater.

[0039] High-pressure sensors are installed at locations such as the compressor's exhaust port to receive the high pressure collected by the high-pressure sensor from the CO2 heat pump water heater in real time, which is then used as the real-time pressure P_high.

[0040] Subtract the real-time pressure P_high of the CO2 heat pump water heater from the target pressure P_opt to obtain the pressure deviation value e_p, that is, e_p = P_opt - P_high.

[0041] Step 104: Calculate the suction superheat deviation between the real-time suction superheat of the heat pump water heater and the target suction superheat.

[0042] In this embodiment, the suction temperature T_suc and evaporation temperature T_evap of the CO2 heat pump water heater can be collected in real time. The suction temperature T_suc is subtracted from the evaporation temperature T_evap to obtain the real-time suction superheat SH of the CO2 heat pump water heater, that is, SH=T_suc-T_evap.

[0043] Subtract the target suction superheat SH_set of the CO2 heat pump water heater from the real-time suction superheat SH to obtain the suction superheat deviation value e_sh, that is, e_sh=SH-SH_set.

[0044] Step 105: Based on the pressure deviation value and the suction superheat deviation value, coordinate the control of the compressor and electronic expansion valve in the heat pump water heater.

[0045] In practical applications, on the one hand, the high pressure and suction superheat in a CO2 heat pump water heater are coupled, and its electronic expansion valve affects both the high pressure and suction superheat. On the other hand, the compressor frequency and the opening degree of the electronic expansion valve in a CO2 heat pump water heater influence each other.

[0046] In this embodiment, the compressor (especially the compressor frequency) and electronic expansion valve (especially the opening degree of the electronic expansion valve) in the heat pump water heater can be controlled in a coordinated manner based on the pressure deviation value e_p and the suction superheat deviation value e_sh. The compressor frequency has a significant impact on the CO2 pressure and can quickly adjust the pressure of the CO2 heat pump water heater. The opening degree of the electronic expansion valve has a significant impact on the suction superheat and can control the magnitude of the suction superheat.

[0047] In one embodiment of the present invention, step 105 may include the following steps: Step 1051: Take the absolute value of the pressure deviation to obtain the pressure adjustment range.

[0048] In this embodiment, the absolute value of the pressure deviation value e_p can be taken to obtain the pressure adjustment range |e_p|.

[0049] Step 1052: Take the absolute value of the intake superheat deviation value to obtain the superheat adjustment range.

[0050] In this embodiment, the absolute value of the intake superheat deviation value e_sh can be taken to obtain the superheat adjustment range |e_sh|.

[0051] Step 1053: Identify the operating status of the heat pump water heater based on the pressure adjustment range and the superheat adjustment range.

[0052] In this embodiment, the pressure adjustment range |e_p| and the superheat adjustment range |e_sh| can be compared with a preset data model to identify the operating status of the CO2 heat pump water heater.

[0053] In the specific implementation, the operating state includes a first control state and a second control state.

[0054] The data model representing the operating status of a CO2 heat pump water heater includes a first pressure threshold Th_p1 (e.g., 0.5 MPa) and a superheat threshold Th_sh (e.g., 5 °C).

[0055] The pressure adjustment amplitude |e_p| is compared with the first pressure threshold Th_p1, and the superheat adjustment amplitude |e_sh| is compared with the superheat threshold Th_sh.

[0056] If the pressure adjustment amplitude |e_p| is greater than the preset first pressure threshold Th_p1 (i.e., |e_p|>Th_p1), and / or the superheat adjustment amplitude |e_sh| is greater than the preset superheat threshold Th_sh (i.e., |e_sh|>Th_sh), then the CO2 heat pump water heater is determined to be in the first control state, which deviates significantly from the ideal operating condition.

[0057] If the pressure adjustment amplitude |e_p| is less than or equal to the preset first pressure threshold Th_p1 (i.e., |e_p|≤Th_p1), and the superheat adjustment amplitude |e_sh| is less than or equal to the preset superheat threshold Th_sh (i.e., |e_sh|≤Th_sh), then the CO2 heat pump water heater is determined to be in the second control state, which is closer to the ideal operating condition.

[0058] Step 1054: In operation, use at least one of the following to control the compressor and electronic expansion valve in the heat pump water heater: pressure deviation value, suction superheat deviation value, pressure adjustment range, and superheat adjustment range.

[0059] When the CO2 heat pump water heater is in different operating states, at least one of the following can be used to coordinate the control of the compressor and electronic expansion valve in the CO2 heat pump water heater: pressure deviation value e_p, suction superheat deviation value e_sh, pressure adjustment range |e_sh|, and superheat adjustment range |e_sh|.

[0060] In one embodiment of the present invention, step 1054 may include the following steps: Step 10541: If the operating state is the first control state, calculate the frequency adjustment amount based on the pressure deviation value.

[0061] If the CO2 heat pump water heater is in the first control state, the frequency adjustment amount ΔF can be calculated based on the pressure deviation value e_p. The frequency adjustment amount ΔF is positively correlated with the pressure deviation value e_p, so as to improve the adjustment efficiency and quickly eliminate the high pressure deviation.

[0062] For example, during operation, the CO2 heat pump water heater can sample the pressure deviation value e_p at preset adjustment cycles Δt, thereby accumulating multiple pressure deviation values ​​e_p.

[0063] Divide the difference between the current pressure deviation value e_p and the previous pressure deviation value e_p_prev by the preset adjustment period Δt to obtain the pressure change rate. Add the product of the preset first pressure adjustment coefficient Kp_p1 (e.g., 0.8 (Hz / MPa)) and the current pressure deviation value e_p, and the product of the preset pressure adjustment weight Kd_p (e.g., 5 (Hz / (MPa•s))) and the pressure change rate to obtain the frequency adjustment amount ΔF.

[0064] In this example, the frequency adjustment ΔF = Kp_p1 × e_p + Kd_p × (e_p - e_p_prev) / Δt.

[0065] Under normal circumstances, the frequency adjustment amount ΔF can be rounded up or down to make it easier to adjust the compressor frequency.

[0066] In addition, the frequency adjustment amount ΔF can be limited according to the first control state, for example, |ΔF|≤5Hz.

[0067] Step 10542: When the pressure adjustment range is less than the preset second pressure threshold, calculate the product between the preset superheat adjustment rate and the intake superheat deviation value to obtain the opening adjustment amount.

[0068] In this embodiment, the pressure adjustment amplitude |e_sh| can be compared with the preset second pressure threshold Th_p2 (e.g., 0.5MPa). When the pressure adjustment amplitude |e_sh| is less than the preset second pressure threshold Th_p2 (i.e., |e_p|≤Th_p2), it indicates that the high pressure is stable. The product between the preset superheat adjustment rate Kp_sh (e.g., 5 (pulses / ℃)) and the intake superheat deviation value e_sh is calculated to obtain the opening adjustment amount Δα, that is, Δα = Kp_sh × e_sh.

[0069] Under normal circumstances, the opening adjustment amount Δα can be rounded up or down to make it easier to adjust the opening of the electronic expansion valve.

[0070] In addition, the opening adjustment amount Δα can be limited according to the first control state, for example, |Δα|≤20 pulses.

[0071] Step 10543: If the operating state is the second control state, then calculate the frequency adjustment amount and opening adjustment amount based on the pressure deviation value, the intake superheat deviation value, the pressure adjustment range and the superheat adjustment range.

[0072] If the CO2 heat pump water heater is in the second control state, the pressure deviation value e_p, the suction superheat deviation value e_sh, the pressure adjustment range |e_sh|, and the superheat adjustment range |e_sh| can be used together to calculate the frequency adjustment amount ΔF and the opening adjustment amount Δα in order to improve the adjustment accuracy.

[0073] On the one hand, the frequency adjustment amount ΔF is positively correlated with the pressure deviation value e_p, the intake superheat deviation value e_sh, the pressure adjustment amplitude |e_sh|, and the superheat adjustment amplitude |e_sh|.

[0074] On the other hand, the opening adjustment amount Δα is positively correlated with the pressure deviation value e_p, the intake superheat deviation value e_sh, the pressure adjustment range |e_sh|, and the superheat adjustment range |e_sh|.

[0075] For example, a first weighting coefficient w_p and a second weighting coefficient w_sh can be calculated.

[0076] Wherein, the first weighting coefficient w_p is the ratio between the pressure regulation amplitude |e_sh| and the total regulation amplitude, and the second weighting coefficient w_sh is the ratio between the superheat regulation amplitude e_sh| and the total regulation amplitude. The total regulation amplitude is the sum of the pressure regulation amplitude |e_sh| and the superheat regulation amplitude e_sh|, that is, w_p=|e_p| / (|e_p|+|e_sh|), w_sh=|e_sh| / (|e_p|+|e_sh|).

[0077] On the one hand, the product of the first weighting coefficient w_p and the first pressure reference value, and the product of the second weighting coefficient w_sh and the first superheat reference value are added together to obtain the frequency adjustment amount ΔF.

[0078] The first pressure reference value is the product of the preset second pressure adjustment coefficient Kp_p2 (e.g., 2.0 (Hz / MPa)) and the pressure deviation value e_p, plus a preset pressure adjustment constant Ki_p (e.g., 0.1Hz).

[0079] The first superheat reference value is the product between the preset superheat regulation rate Kp_sh (e.g., 5.0 (pulse / ℃)) and the intake superheat deviation value e_sh.

[0080] Then, ΔF= w_p×[Kp_p2×e_p+Ki_p]+w_sh×[Kp_sh×e_sh].

[0081] Under normal circumstances, the frequency adjustment amount ΔF can be rounded up or down to make it easier to adjust the compressor frequency.

[0082] In addition, the frequency adjustment amount ΔF can be limited according to the second control state. The amplitude of the frequency adjustment amount ΔF in the second control state is smaller than that in the first control state. For example, |ΔF|≤3Hz.

[0083] On the other hand, the product of the first weighting coefficient w_p and the second pressure reference value, and the product of the second weighting coefficient w_sh and the second superheat reference value are added together to obtain the opening adjustment amount Δα.

[0084] The second pressure reference value is the product of the preset second pressure adjustment coefficient Kp_p2 and the pressure deviation value e_p.

[0085] The second superheat reference value is based on the product of the preset superheat adjustment rate Kp_sh and the intake superheat deviation value, plus a preset superheat adjustment constant.

[0086] Then, Δα = w_sh×[Kp_sh×e_sh+Ki_sh]+w_p×[Kp_p2×e_p].

[0087] Under normal circumstances, the opening adjustment amount Δα can be rounded up or down to make it easier to adjust the opening of the electronic expansion valve.

[0088] In addition, the opening adjustment amount Δα can be limited according to the second control state. The amplitude of the opening adjustment amount Δα in the second control state is smaller than that in the first control state. For example, |Δα|≤10 pulses.

[0089] Step 10544: Adjust the frequency of the compressor in the heat pump water heater according to the frequency adjustment amount in the direction indicated by the pressure deviation value.

[0090] In this embodiment, the positive or negative value of the pressure deviation value e_p indicates the direction of adjusting the frequency of the compressor in the CO2 heat pump water heater. In the direction indicated by the pressure deviation value e_p, the frequency of the compressor in the CO2 heat pump water heater is adjusted according to the frequency adjustment amount ΔF.

[0091] If the pressure deviation value e_p is greater than 0 (i.e., e_p>0), then the frequency of the compressor in the CO2 heat pump water heater is increased according to the frequency adjustment amount.

[0092] If the pressure deviation value e_p is less than 0 (i.e., e_p < 0), then the frequency of the compressor in the CO2 heat pump water heater is reduced according to the frequency adjustment amount.

[0093] Step 10545: In the direction indicated by the suction superheat deviation value, adjust the opening of the electronic expansion valve in the heat pump water heater according to the opening adjustment amount.

[0094] In this embodiment, the positive or negative value of the intake superheat deviation value e_sh indicates the direction of adjusting the opening of the electronic expansion valve in the CO2 heat pump water heater. In the direction indicated by the intake superheat deviation value e_sh, the opening of the electronic expansion valve in the CO2 heat pump water heater is adjusted according to the opening adjustment amount Δα.

[0095] If the intake superheat deviation value e_sh is greater than 0 (i.e., e_sh>0), then the opening of the electronic expansion valve in the CO2 heat pump water heater is increased according to the opening adjustment amount.

[0096] If the intake superheat deviation value e_sh is less than 0 (i.e., e_sh < 0), then the opening of the electronic expansion valve in the CO2 heat pump water heater is reduced according to the opening adjustment amount.

[0097] In this embodiment, a target pressure for carbon dioxide in the first loop of the heat pump water heater is set; the pressure in the first loop is greater than the critical pressure of carbon dioxide; a target suction superheat is set for the heat pump water heater; the pressure deviation between the target pressure and the real-time pressure of the heat pump water heater is calculated; the suction superheat deviation between the real-time suction superheat and the target suction superheat is calculated; and the compressor and electronic expansion valve in the heat pump water heater are controlled collaboratively based on the pressure deviation and suction superheat deviation. This embodiment combines high pressure and suction superheat to collaboratively control the compressor and electronic expansion valve in the CO2 heat pump water heater, decoupling the high pressure and suction superheat, and decoupling the compressor and electronic expansion valve, effectively improving the control efficiency of the CO2 heat pump water heater and maintaining its efficient, stable, and reliable operation.

[0098] It should be noted that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0099] Reference Figure 3 The diagram shows a control device for a carbon dioxide heat pump water heater according to an embodiment of the present invention, which may specifically include the following modules: The target pressure setting module 301 is used to set the target pressure of carbon dioxide in the first circuit of the heat pump water heater; the pressure in the first circuit is greater than the critical pressure of carbon dioxide. The target intake superheat setting module 302 is used to set the target intake superheat for the heat pump water heater. The pressure deviation calculation module 303 is used to calculate the pressure deviation between the target pressure and the real-time pressure of the heat pump water heater; The intake superheat deviation calculation module 304 is used to calculate the intake superheat deviation between the real-time intake superheat of the heat pump water heater and the target intake superheat. The collaborative control module 305 is used to collaboratively control the compressor and electronic expansion valve in the heat pump water heater based on the pressure deviation value and the suction superheat deviation value.

[0100] In one embodiment of the present invention, the target pressure setting module 301 includes: The outlet water temperature detection module is used to detect the outlet water temperature of the gas cooler in the first loop of the heat pump water heater; The evaporation temperature calculation module is used to calculate the evaporation temperature of carbon dioxide in the second loop of the heat pump water heater; the pressure in the second loop is less than the critical pressure of carbon dioxide. The target pressure fusion module is used to fuse the outlet water temperature and the evaporation temperature into a target pressure of carbon dioxide in the first loop of the heat pump water heater; the target pressure is positively correlated with both the outlet water temperature and the evaporation temperature.

[0101] In one embodiment of the present invention, the target pressure fusion module includes: The linear fusion module is used to add the product of the outlet water temperature and the preset first fusion coefficient, the product of the evaporation temperature and the preset second fusion coefficient, and the preset reference value to obtain the target pressure of carbon dioxide in the first loop of the heat pump water heater.

[0102] In one embodiment of the present invention, the collaborative control module 305 includes: The pressure adjustment range calculation module is used to take the absolute value of the pressure deviation value to obtain the pressure adjustment range. The superheat adjustment range calculation module is used to take the absolute value of the intake superheat deviation value to obtain the superheat adjustment range; An operating status identification module is used to identify the operating status of the heat pump water heater based on the pressure adjustment range and the superheat adjustment range; The classification control module is used to coordinately control the compressor and electronic expansion valve in the heat pump water heater using at least one of the pressure deviation value, the suction superheat deviation value, the pressure adjustment range, and the superheat adjustment range during the operation state.

[0103] In one embodiment of the present invention, the operating state includes a first control state and a second control state; the operating state identification module includes: The first control state determination module is used to determine that the heat pump water heater is in the first control state if the pressure adjustment amplitude is greater than the preset first pressure threshold and / or the superheat adjustment amplitude is greater than the preset superheat threshold. The second control state determination module is used to determine that the heat pump water heater is in the second control state if the pressure adjustment amplitude is less than or equal to a preset first pressure threshold and the superheat adjustment amplitude is less than or equal to a preset superheat threshold.

[0104] In one embodiment of the present invention, the classification control module includes: The first frequency adjustment calculation module is used to calculate the frequency adjustment amount based on the pressure deviation value if the operating state is the first control state; the frequency adjustment amount is positively correlated with the pressure deviation value. The first opening adjustment amount calculation module is used to calculate the product between the preset superheat adjustment rate and the intake superheat deviation value when the pressure adjustment amplitude is less than the preset second pressure threshold, so as to obtain the opening adjustment amount. The adjustment amount collaborative calculation module is used to collaboratively calculate the frequency adjustment amount and the opening adjustment amount based on the pressure deviation value, the intake superheat deviation value, the pressure adjustment amplitude, and the superheat adjustment amplitude if the operating state is the second control state; the frequency adjustment amount is positively correlated with the pressure deviation value, the intake superheat deviation value, the pressure adjustment amplitude, and the superheat adjustment amplitude, and the opening adjustment amount is positively correlated with the pressure deviation value, the intake superheat deviation value, the pressure adjustment amplitude, and the superheat adjustment amplitude; The compressor adjustment module is used to adjust the frequency of the compressor in the heat pump water heater in the direction indicated by the pressure deviation value according to the frequency adjustment amount; An electronic expansion valve adjustment module is used to adjust the opening of the electronic expansion valve in the heat pump water heater in the direction indicated by the suction superheat deviation value, according to the opening adjustment amount.

[0105] In one embodiment of the present invention, the first frequency adjustment calculation module includes: The pressure change rate calculation module is used to divide the difference between the current pressure deviation value and the previous pressure deviation value by a preset adjustment period to obtain the pressure change rate. The high-pressure frequency calculation module is used to add the product of the preset first pressure adjustment coefficient and the current pressure deviation value, and the product of the preset pressure adjustment weight and the pressure change rate, to obtain the frequency adjustment amount.

[0106] In one embodiment of the present invention, the adjustment amount collaborative calculation module includes: The weighting coefficient calculation module is used to calculate a first weighting coefficient and a second weighting coefficient; the first weighting coefficient is the ratio between the pressure adjustment range and the total adjustment range, the second weighting coefficient is the ratio between the superheat adjustment range and the total adjustment range, and the total adjustment range is the sum of the pressure adjustment range and the superheat adjustment range; The second frequency adjustment calculation module is used to add the product between the first weighting coefficient and the first pressure reference value, and the product between the second weighting coefficient and the first superheat reference value to obtain the frequency adjustment amount; the first pressure reference value is based on the product between the preset second pressure adjustment coefficient and the pressure deviation value plus a preset pressure adjustment constant; the first superheat reference value is the product between the preset superheat adjustment rate and the intake superheat deviation value. The second opening adjustment calculation module is used to add the product between the first weighting coefficient and the second pressure reference value, and the product between the second weighting coefficient and the second superheat reference value to obtain the opening adjustment amount; the second pressure reference value is the product between the preset second pressure adjustment coefficient and the pressure deviation value, and the second superheat reference value is the product between the preset superheat adjustment rate and the intake superheat deviation value plus a preset superheat adjustment constant.

[0107] In one embodiment of the present invention, the compressor regulating module includes: The frequency boosting module is used to increase the frequency of the compressor in the heat pump water heater according to the frequency adjustment amount if the pressure deviation value is greater than 0. The frequency reduction module is used to reduce the frequency of the compressor in the heat pump water heater according to the frequency adjustment amount if the pressure deviation value is less than 0.

[0108] In one embodiment of the present invention, the electronic expansion valve regulating module includes: The activation module is used to increase the opening of the electronic expansion valve in the heat pump water heater according to the opening adjustment amount if the suction superheat deviation value is greater than 0. The shut-off module is used to reduce the opening of the electronic expansion valve in the heat pump water heater according to the opening adjustment amount if the intake superheat deviation value is less than 0.

[0109] The present invention provides a control device for a carbon dioxide heat pump water heater. By using the control device for the carbon dioxide heat pump water heater, the various steps in the aforementioned control method embodiments of the carbon dioxide heat pump water heater can be realized.

[0110] It should be noted that the module division in the control devices of various carbon dioxide heat pump water heaters provided in the above embodiments is illustrative and only represents a logical functional division. In actual implementation, other division methods may also be used. Furthermore, the functional modules in the various embodiments of this invention can be integrated into a single processor, exist as separate physical entities, or be integrated into a single module. The integrated modules described above can be implemented in hardware or as software functional modules.

[0111] If the integrated module is implemented as a software functional module and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the technical solution of the embodiments of the present invention can be embodied in the form of a computer program product, which is stored in a computer storage medium and includes several instructions to cause an electronic device or processor to execute all or part of the steps of the methods in the various embodiments of the present invention. The aforementioned computer storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0112] Furthermore, the control device for the carbon dioxide heat pump water heater provided in the above embodiments and the control method for the carbon dioxide heat pump water heater belong to the same concept. For details of its implementation process, please refer to the method embodiments, which will not be repeated here.

[0113] Reference Figure 4 The diagram illustrates an electronic device according to an embodiment of the present invention. Figure 4As shown, the electronic device in this embodiment of the invention includes: a processor, a memory, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps in the control method embodiment of the carbon dioxide heat pump water heater described above. Alternatively, when the processor executes the computer program, it implements the functions of each module in the control device embodiment of the carbon dioxide heat pump water heater described above.

[0114] For example, the computer program may be divided into one or more modules, which are stored in the memory and executed by the processor to complete this application. The one or more modules may be a series of computer program instruction segments capable of performing a specific function, which can be used to describe the execution process of the computer program in the electronic device.

[0115] The electronic device may be a desktop computer, a cloud server, or other computing device. The electronic device may include, but is not limited to, a processor and memory. Those skilled in the art will understand that... Figure 4 This is merely one example of an electronic device and does not constitute a limitation on the electronic device. It may include more or fewer components than illustrated, or combine certain components, or different components. For example, the electronic device may also include input / output devices, network access devices, buses, etc.

[0116] The processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor.

[0117] The memory can be an internal storage unit of the electronic device, such as a hard drive or RAM. Alternatively, it can be an external storage device, such as a plug-in hard drive, Smart Media Card (SMC), Secure Digital (SD) card, Flash Card, etc. Furthermore, the memory can include both internal and external storage units. The memory is used to store the computer program and other programs and data required by the electronic device. The memory can also be used to temporarily store data that has been output or will be output.

[0118] This invention also discloses an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the control method for a carbon dioxide heat pump water heater as described in the foregoing embodiments.

[0119] This invention also discloses a computer-readable storage medium storing a computer program that, when executed by a processor, implements the control method for a carbon dioxide heat pump water heater as described in the foregoing embodiments.

[0120] This invention also discloses a computer program product that, when run on a computer, causes the computer to execute the control method for the carbon dioxide heat pump water heater described in the foregoing embodiments.

[0121] The embodiments described above are only used to illustrate the technical solutions of this application, and are not intended to limit it. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A control method for a carbon dioxide heat pump water heater, characterized in that, include: Set a target pressure for carbon dioxide in the first circuit of the heat pump water heater; the pressure in the first circuit is greater than the critical pressure of carbon dioxide. Set a target intake superheat for the heat pump water heater; Calculate the pressure deviation between the target pressure and the real-time pressure of the heat pump water heater; Calculate the suction superheat deviation between the real-time suction superheat of the heat pump water heater and the target suction superheat; The compressor and electronic expansion valve in the heat pump water heater are controlled in coordination based on the pressure deviation value and the intake superheat deviation value.

2. The method according to claim 1, characterized in that, Setting the target pressure of carbon dioxide in the first circuit of the heat pump water heater includes: Detect the outlet water temperature of the gas cooler in the first loop of the heat pump water heater; Calculate the evaporation temperature of carbon dioxide in the second loop of the heat pump water heater; the pressure in the second loop is less than the critical pressure of carbon dioxide. The outlet water temperature and the evaporation temperature are combined to form the target carbon dioxide pressure in the first loop of the heat pump water heater; the target pressure is positively correlated with both the outlet water temperature and the evaporation temperature.

3. The method according to claim 2, characterized in that, The step of integrating the outlet water temperature and the evaporation temperature into the target pressure of carbon dioxide in the first loop of the heat pump water heater includes: The target pressure of carbon dioxide in the first loop of the heat pump water heater is obtained by multiplying the outlet water temperature by a preset first fusion coefficient, the evaporation temperature by a preset second fusion coefficient, and a preset reference value.

4. The method according to any one of claims 1-3, characterized in that, The method of coordinating the control of the compressor and electronic expansion valve in the heat pump water heater based on the pressure deviation value and the suction superheat deviation value includes: The pressure adjustment range is obtained by taking the absolute value of the pressure deviation. The absolute value of the intake superheat deviation is taken to obtain the superheat adjustment range; The operating status of the heat pump water heater is identified based on the pressure adjustment range and the superheat adjustment range; In the operating state, at least one of the pressure deviation value, the suction superheat deviation value, the pressure adjustment range, and the superheat adjustment range is used to coordinately control the compressor and electronic expansion valve in the heat pump water heater.

5. The method according to claim 4, characterized in that, The operating state includes a first control state and a second control state; identifying the operating state of the heat pump water heater based on the pressure adjustment range and the superheat adjustment range includes: If the pressure adjustment range is greater than a preset first pressure threshold, and / or the superheat adjustment range is greater than a preset superheat threshold, then the heat pump water heater is determined to be in a first control state. If the pressure adjustment range is less than or equal to a preset first pressure threshold, and the superheat adjustment range is less than or equal to a preset superheat threshold, then the heat pump water heater is determined to be in a second control state.

6. The method according to claim 5, characterized in that, In the operating state, the compressor and electronic expansion valve in the heat pump water heater are controlled in coordination using at least one of the pressure deviation value, the suction superheat deviation value, the pressure adjustment range, and the superheat adjustment range, including: If the operating state is the first control state, then the frequency adjustment amount is calculated based on the pressure deviation value; the frequency adjustment amount is positively correlated with the pressure deviation value. When the pressure adjustment range is less than the preset second pressure threshold, the product between the preset superheat adjustment rate and the intake superheat deviation value is calculated to obtain the opening adjustment amount. If the operating state is the second control state, then the frequency adjustment amount and the opening adjustment amount are calculated collaboratively based on the pressure deviation value, the intake superheat deviation value, the pressure adjustment range, and the superheat adjustment range; the frequency adjustment amount is positively correlated with the pressure deviation value, the intake superheat deviation value, the pressure adjustment range, and the superheat adjustment range, and the opening adjustment amount is positively correlated with the pressure deviation value, the intake superheat deviation value, the pressure adjustment range, and the superheat adjustment range; In the direction indicated by the pressure deviation value, the frequency of the compressor in the heat pump water heater is adjusted according to the frequency adjustment amount; In the direction indicated by the suction superheat deviation value, the opening of the electronic expansion valve in the heat pump water heater is adjusted according to the opening adjustment amount.

7. The method according to claim 6, characterized in that, The calculation of the frequency adjustment amount based on the pressure deviation value includes: The pressure change rate is obtained by dividing the difference between the current pressure deviation value and the previous pressure deviation value by the preset adjustment period. The frequency adjustment amount is obtained by multiplying the preset first pressure adjustment coefficient by the current pressure deviation value and the preset pressure adjustment weight by the pressure change rate. The calculation of frequency adjustment and opening adjustment based on the pressure deviation value, the intake superheat deviation value, the pressure adjustment amplitude, and the superheat adjustment amplitude includes: Calculate a first weighting coefficient and a second weighting coefficient; the first weighting coefficient is the ratio between the pressure adjustment range and the total adjustment range, the second weighting coefficient is the ratio between the superheat adjustment range and the total adjustment range, and the total adjustment range is the sum of the pressure adjustment range and the superheat adjustment range; The frequency adjustment amount is obtained by multiplying the first weighting coefficient and the first pressure reference value, and by adding the product of the second weighting coefficient and the first superheat reference value; the first pressure reference value is the product of the preset second pressure adjustment coefficient and the pressure deviation value plus a preset pressure adjustment constant; the first superheat reference value is the product of the preset superheat adjustment rate and the intake superheat deviation value. The opening adjustment amount is obtained by multiplying the first weighting coefficient and the second pressure reference value, and by adding the product of the second weighting coefficient and the second superheat reference value; the second pressure reference value is the product of the preset second pressure adjustment coefficient and the pressure deviation value, and the second superheat reference value is the product of the preset superheat adjustment rate and the intake superheat deviation value plus a preset superheat adjustment constant.

8. The method according to claim 6, characterized in that, Adjusting the frequency of the compressor in the heat pump water heater according to the frequency adjustment amount in the direction indicated by the pressure deviation value includes: If the pressure deviation value is greater than 0, the frequency of the compressor in the heat pump water heater is increased according to the frequency adjustment amount; If the pressure deviation value is less than 0, the frequency of the compressor in the heat pump water heater is reduced according to the frequency adjustment amount. Adjusting the opening of the electronic expansion valve in the heat pump water heater according to the opening adjustment amount in the direction indicated by the suction superheat deviation value includes: If the suction superheat deviation value is greater than 0, then the opening of the electronic expansion valve in the heat pump water heater is increased according to the opening adjustment amount. If the suction superheat deviation value is less than 0, then the opening of the electronic expansion valve in the heat pump water heater is reduced according to the opening adjustment amount.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the control method for a carbon dioxide heat pump water heater as described in any one of claims 1-8.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the control method for the carbon dioxide heat pump water heater as described in any one of claims 1-8.

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