Variable frequency heat pump control method and variable frequency heat pump system

Abstract

The invention relates to a variable-frequency heat pump control method and a variable-frequency heat pump system.The variable-frequency heat pump control method is applied to a variable-frequency heat pump unit, the variable-frequency heat pump unit comprises a compressor, an expansion valve and a pressure sensing module, the compressor communicates with the expansion valve, and the pressure sensing module is used for detecting port pressure data of the compressor; the variable frequency heat pump control method comprises the following steps that port pressure data detected by a pressure sensing module is obtained; based on a preset opening degree model, processing the port pressure data to obtain opening degree data of the corresponding expansion valve; and the opening degree of the expansion valve is adjusted according to the opening degree pressure data, and efficient and energy-saving control over the variable frequency heat pump unit is achieved. According to the port pressure of the compressor, the opening degree of the expansion valve is intelligently adjusted, the operation state of the variable-frequency heat pump unit is adjusted, and the variable-frequency heat pump unit is kept in the optimal operation state.

Description

Technical Field

[0001] The present application relates to the technical field of heat pumps, and particularly to a variable-frequency heat pump control method and a variable-frequency heat pump system. Background Art

[0002] A variable-frequency heat pump unit is an efficient and energy-saving heating and cooling device, which has a wide range of applications in multiple fields. The variable-frequency heat pump unit realizes the transfer of heat through the circulation process of the refrigerant in components such as the evaporator, compressor, condenser, and expansion valve. The variable-frequency heat pump unit can absorb heat from a low-temperature heat source and release the heat to a high-temperature environment through the compression and condensation processes, thereby achieving the purpose of refrigeration or heating. This heat transfer process enables the variable-frequency heat pump unit to provide refrigeration or heating services with a high energy efficiency ratio.

[0003] In the implementation process, the inventor found that there are at least the following problems in the traditional technology: the actual operating efficiency of the existing variable-frequency heat pump unit is relatively low, and the energy-saving effect is poor. Summary of the Invention

[0004] Based on this, in view of the problem that the actual operating efficiency of the existing variable-frequency heat pump unit is relatively low and the energy-saving effect is poor, it is necessary to provide a variable-frequency heat pump control method and a variable-frequency heat pump system that can adjust the operating state of the variable-frequency heat pump unit to keep the variable-frequency heat pump unit operating in a highly energy-saving state.

[0005] To achieve the above object, an embodiment of the present invention provides a variable-frequency heat pump control method, which is applied to a variable-frequency heat pump unit. The variable-frequency heat pump unit includes a compressor, an expansion valve, and a pressure sensing module. The compressor is connected to the expansion valve, and the pressure sensing module is used to detect the port pressure data of the compressor. The variable-frequency heat pump control method includes the following steps:

[0006] Obtain the port pressure data detected by the pressure sensing module;

[0007] Based on a preset opening pressure model, process the port pressure data to obtain the opening data corresponding to the expansion valve;

[0008] Adjust the opening of the expansion valve according to the opening data.

[0009] In one embodiment, the pressure sensing module includes a first pressure sensor, a second pressure sensor, and a third pressure sensor; the first pressure sensor is used to detect the exhaust pressure data at the exhaust end of the compressor, the second pressure sensor is used to detect the suction pressure data at the suction end of the compressor, and the third pressure sensor is used to detect the return pressure data at the return end of the compressor;

[0010] The step of processing the port pressure data based on a preset opening model to obtain the opening data corresponding to the expansion valve includes:

[0011] Based on a preset opening pressure model, the exhaust pressure data, the suction pressure data, and the return air pressure data are processed to obtain the opening data of the corresponding expansion valve.

[0012] In one embodiment, the steps of processing the exhaust pressure data, the suction pressure data, and the return air pressure data based on a preset opening pressure model to obtain the opening data of the corresponding expansion valve include:

[0013] Based on a preset pressure sub-model, the exhaust pressure data and the suction pressure data are processed to obtain the target return air pressure data;

[0014] According to the target return air pressure data and the return air pressure data, the pressure difference and the pressure difference change rate are obtained;

[0015] Based on a preset opening sub-model, the pressure difference and the pressure difference change rate are processed to obtain the opening data.

[0016] In one embodiment, the preset pressure sub-model is:

[0017]

[0018] Wherein, TMp is the target return air pressure data, Hp is the exhaust pressure data, Lp is the suction pressure data, β is the first constant, and δ is the second constant.

[0019] In one embodiment, the steps of obtaining the pressure difference and the pressure difference change rate according to the target return air pressure data and the return air pressure data include:

[0020] The difference between the return air pressure data and the target return air pressure data is processed to obtain the pressure difference;

[0021] The current pressure difference and the previous pressure difference are obtained, and the change rate of the current pressure difference and the previous pressure difference is processed to obtain the pressure difference change rate.

[0022] In one embodiment, the preset opening sub-model is:

[0023] P2 = △Mp n *k1 + △Mp c *k2 + k3

[0024] Wherein, P2 is the opening data, △Mp n is the pressure difference, △Mp c is the pressure difference change rate, k1 is the third constant, k2 is the fourth constant, and k3 is the fifth constant.

[0025] In one embodiment, the variable-frequency heat pump unit further includes a first heat exchanger, a fan module, and a first temperature sensor. The first heat exchanger is connected to the compressor. The fan module is arranged at the air outlet end of the first heat exchanger, and the first temperature sensor is arranged at the air inlet end of the first heat exchanger. The first temperature sensor is used to detect the current ambient temperature of the variable-frequency heat pump unit. The variable-frequency heat pump control method further includes the steps:

[0026] Obtain the current ambient temperature data detected by the first temperature sensor and the suction pressure data detected by the second pressure sensor;

[0027] According to the suction pressure data, obtain the saturation temperature data of the corresponding refrigerant;

[0028] Based on a preset speed model, process the saturation temperature data and the current ambient temperature data to obtain the speed data corresponding to the fan module;

[0029] Adjust the speed of the fan module according to the speed data.

[0030] In one embodiment, the step of processing the saturation temperature data and the current ambient temperature data based on a preset speed model to obtain the speed data corresponding to the fan module includes:

[0031] According to the saturation temperature data and the current ambient temperature data, obtain a first temperature difference and a first temperature difference change rate;

[0032] Based on a preset speed model, process the first temperature difference and the first temperature difference change rate to obtain the speed data.

[0033] In one embodiment, the preset speed model is:

[0034] Pr = △T n *kx + △T c *ky + kz

[0035] Where Pr is the speed data, △T n is the temperature difference, △T c is the temperature difference change rate, kx is the sixth constant, ky is the seventh constant, and kz is the eighth constant.

[0036] In one embodiment, the variable-frequency heat pump unit further includes a second heat exchanger and a second temperature sensor; the second heat exchanger is connected to the compressor, and the second temperature sensor is arranged at the input end or the output end of the second heat exchanger. The second temperature sensor is used to detect the port temperature data of the second heat exchanger. The steps for obtaining the first constant and the second constant include:

[0037] Obtain the port temperature data detected by the second temperature sensor;

[0038] The first temperature difference and the change rate of the first temperature difference obtained based on the port temperature data and the preset temperature threshold;

[0039] Based on the first temperature difference and the change rate of the first temperature difference, obtain the operating frequency of the compressor;

[0040] According to the operating frequency and the current ambient temperature, query the first preset mapping relation table to obtain the first constant;

[0041] According to the operating frequency and the current ambient temperature, query the second preset mapping relation table to obtain the second constant.

[0042] On the other hand, an embodiment of the present invention further provides a variable frequency heat pump system, including a control device and a variable frequency heat pump unit; the control device is connected to the variable frequency heat pump unit;

[0043] The control device is used to execute the steps of the variable frequency heat pump control method in any one of the above.

[0044] In one embodiment, the variable frequency heat pump system further includes a water using device; the variable frequency heat pump unit includes a compressor, an expansion valve, a first heat exchanger, a second heat exchanger and a pressure sensing module; the compressor, the expansion valve, the first heat exchanger and the second heat exchanger are connected in communication to form a refrigerant circulation path; the second heat exchanger is connected to the water using device to form a water temperature adjustment path; the pressure sensing module is arranged at the port of the compressor;

[0045] The control device is respectively connected to the compressor, the expansion valve and the pressure sensing module.

[0046] One of the above technical solutions has the following advantages and beneficial effects:

[0047] In each embodiment of the above variable frequency heat pump control method, it is applied to a variable frequency heat pump unit, the variable frequency heat pump unit includes a compressor, an expansion valve and a pressure sensing module, the compressor is connected to the expansion valve, and the pressure sensing module is used to detect the port pressure data of the compressor; the variable frequency heat pump control method includes the following steps: obtain the port pressure data detected by the pressure sensing module; based on the preset opening model, process the port pressure data to obtain the opening data corresponding to the expansion valve; according to the opening pressure data, adjust the opening of the expansion valve to realize the efficient energy-saving control of the variable frequency heat pump unit. This application intelligently adjusts the opening of the expansion valve according to the port pressure of the compressor, realizes the adjustment of the operating state of the variable frequency heat pump unit, and keeps the operating state of the variable frequency heat pump unit in the best operating state. Description of the Drawings

[0048] Figure 1 It is a schematic diagram of the application environment of the variable frequency heat pump control method in one embodiment;

[0049] Figure 2It is the first process schematic diagram of the variable-frequency heat pump control method in an embodiment;

[0050] Figure 3 It is the process schematic diagram of the opening degree data acquisition step in an embodiment;

[0051] Figure 4 It is the second process schematic diagram of the variable-frequency heat pump control method in an embodiment;

[0052] Figure 5 It is the process schematic diagram of the rotational speed data acquisition step in an embodiment;

[0053] Figure 6 It is the process schematic diagram of the acquisition steps of the first constant and the second constant in an embodiment;

[0054] Figure 7 It is the first structural schematic diagram of the variable-frequency heat pump system in an embodiment;

[0055] Figure 8 It is the second structural schematic diagram of the variable-frequency heat pump system in an embodiment. Detailed implementation manners

[0056] In order to enable those skilled in the art of this technology to better understand the solution of this application, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of this application.

[0057] It should be noted that the terms "first", "second", etc. in the description and claims of this application and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily need to describe a specific order or sequence. It should be understood that such used data can be interchanged under appropriate circumstances so as to describe the embodiments of this application here. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device including a series of steps or units does not necessarily have to be limited to those clearly listed steps or units, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0058] In addition, the meaning of the term "plural" should be two or more.

[0059] The variable-frequency heat pump control method provided by this application can be applied to, for example Figure 1In the application environment shown. Among them, the processing device may include a processor 102 and a memory 104. The memory 104 can be used to store data such as port pressure data and opening data. The processor 102 is used to obtain the port pressure data detected by the pressure sensing module; based on a preset opening pressure model, process the port pressure data to obtain the opening data of the corresponding expansion valve; and adjust the opening of the expansion valve according to the opening data. The processing device may further include a display 106, and the display 106 can display data such as port pressure data and opening data through a graphical interface. Among them, the processing device is applied to a variable-frequency heat pump system, and the variable-frequency heat pump system can be an all-in-one hot water machine. The variable-frequency heat pump system is provided with a variable-frequency heat pump unit, and the variable-frequency heat pump unit includes a compressor, an expansion valve, and a pressure sensing module. The compressor is connected to the expansion valve; the processing device is connected to the compressor, the expansion valve, and the pressure sensing module; and the pressure sensing module is used to detect the port pressure data of the compressor.

[0060] In one embodiment, as Figure 2 shown, a variable-frequency heat pump control method is provided. Taking the processor 102 in Figure 1 as an example for illustration, it includes the following steps:

[0061] Step S210, obtain the port pressure data detected by the pressure sensing module.

[0062] Among them, the compressor can be used to suck in the low-temperature and low-pressure refrigerant in the evaporator and become a high-temperature and high-pressure gas after compression. The function of the compressor is to increase the pressure and temperature of the refrigerant so that it can release more heat. The expansion valve can be used to throttle and depressurize the refrigerant into a low-temperature and low-pressure liquid; for example, after the high-temperature and high-pressure refrigerant passes through the condenser, it becomes a high-pressure liquid. Then, the refrigerant passes through the expansion valve, and the pressure drops rapidly, making the refrigerant become a low-temperature and low-pressure state, so as to be ready to enter the evaporator for recycling.

[0063] The pressure sensing module may include at least 2 pressure sensors, and the pressure sensing module is used to detect the port pressure data of the compressor. For example, the pressure sensing module includes 3 pressure sensors, and the compressor has 3 ports, then the 3 pressure sensors are arranged in one-to-one correspondence with the 3 ports of the compressor to detect the pressure of each port of the compressor.

[0064] The variable-frequency heat pump unit also includes a condenser, an evaporator and a four-way valve. The evaporator is a heat exchanger in the variable-frequency heat pump unit, and it absorbs low-temperature heat energy from the outside air (or water source). During operation, the low-temperature refrigerant passes through the evaporator and exchanges heat with the outside air (or water source), causing the refrigerant to evaporate and absorb heat. This process cools the outside air (or water source), and the refrigerant becomes a low-temperature and low-pressure gas. The condenser is used to input high-temperature and high-pressure refrigerant, and the high-temperature and high-pressure refrigerant exchanges heat with hot water. The high-temperature heat released by the refrigerant is transferred to the hot water, thereby increasing the temperature of the hot water. During this process, the refrigerant changes from a gaseous state to a liquid state, releasing a large amount of heat.

[0065] The functions of the four-way valve in the variable-frequency heat pump unit mainly include changing the flow direction of the refrigerant, realizing the switching between the refrigeration and heating modes, etc. By changing the flow direction of the refrigerant, the functions of the condenser and the evaporator can be interchanged, thereby realizing the temperature adjustment of the air or water source. Exemplarily, the four-way valve controls the movement of the core iron through an electromagnetic coil, thereby changing the flow direction of the refrigerant. When set to the refrigeration state, the electromagnetic coil is powered off, and the refrigerant flows to the evaporator to realize the refrigeration cycle; when set to the heating state, the electromagnetic coil is powered on, and the refrigerant flows to the condenser to realize the heating cycle.

[0066] Step S220: Based on a preset opening-pressure model, process the port pressure data to obtain the opening data of the corresponding expansion valve.

[0067] Among them, the preset opening-pressure model can be established through historical test data. The opening data refers to the opening size of the expansion valve.

[0068] By inputting the corresponding compressor port pressure data into the preset opening-pressure model for processing, the opening data of the corresponding expansion valve is output.

[0069] Step S230: Adjust the opening of the expansion valve according to the opening data.

[0070] According to the opening data of the corresponding expansion valve, perform the valve-opening action of the expansion valve, thereby realizing the precise adjustment of the opening of the expansion valve and optimizing the operating state of the variable-frequency heat pump unit.

[0071] In the above embodiments, by obtaining the port pressure data detected by the pressure sensing module; based on the preset opening-pressure model, processing the port pressure data to obtain the opening data of the corresponding expansion valve; adjusting the opening of the expansion valve according to the opening data, the high-efficiency and energy-saving control of the variable-frequency heat pump unit is realized. This application intelligently adjusts the opening of the expansion valve according to the port pressure of the compressor, realizes the adjustment of the operating state of the variable-frequency heat pump unit, and keeps the operating state of the variable-frequency heat pump unit in the best operating state.

[0072] In one embodiment, the pressure sensing module includes a first pressure sensor, a second pressure sensor, and a third pressure sensor; the first pressure sensor is used to detect the exhaust pressure data at the exhaust end of the compressor, the second pressure sensor is used to detect the suction pressure data at the suction end of the compressor, and the third pressure sensor is used to detect the return air pressure data at the return air end of the compressor.

[0073] The steps of processing the port pressure data based on a preset opening pressure model to obtain the opening data of the corresponding expansion valve include: processing the exhaust pressure data, the suction pressure data, and the return air pressure data based on the preset opening pressure model to obtain the opening data of the corresponding expansion valve.

[0074] Among them, the compressor is based on the exhaust end, the suction end, and the return air end; the suction end of the compressor is used to suck in low-temperature and low-pressure refrigerant; the exhaust end of the compressor is used to discharge the high-temperature and high-pressure gas after compression; the return air end of the compressor refers to the enthalpy-increasing air supply port of the compressor. The first pressure sensor can be arranged at the exhaust end of the compressor to detect the exhaust pressure at the exhaust end of the compressor, so as to obtain the exhaust pressure data; the second pressure sensor can be arranged at the suction end of the compressor to detect the suction pressure at the suction end of the compressor, so as to obtain the suction pressure data; the third pressure sensor can be arranged at the return air end of the compressor to detect the return air pressure at the return air end of the compressor, so as to obtain the return air pressure data.

[0075] By inputting the exhaust pressure data, the suction pressure data, and the return air pressure data of the corresponding compressor into the preset opening pressure model for processing, and then outputting the opening data of the corresponding expansion valve. According to the opening data of the corresponding expansion valve, the valve opening action of the expansion valve is executed, thereby realizing the precise adjustment of the opening of the expansion valve, optimizing the operating state of the variable-frequency heat pump unit, and realizing the efficient energy-saving control of the variable-frequency heat pump unit. In this application, according to the port pressure of the compressor, the opening of the expansion valve is intelligently adjusted to realize the adjustment of the operating state of the variable-frequency heat pump unit, so that the operating state of the variable-frequency heat pump unit remains in the best operating state.

[0076] In one embodiment, as Figure 3 shown, the steps of processing the exhaust pressure data, the suction pressure data, and the return air pressure data based on the preset opening pressure model to obtain the opening data of the corresponding expansion valve include:

[0077] Step S310, processing the exhaust pressure data and the suction pressure data based on the preset pressure sub-model to obtain the target return air pressure data.

[0078] Among them, the preset pressure sub-model can be established through historical exhaust pressure data, historical suction pressure data, and historical return air pressure data. The target return air pressure data refers to the target pressure value of the third pressure sensor that needs to be controlled.

[0079] By inputting the exhaust pressure data and the suction pressure data into a preset pressure sub-model for processing, the target return air pressure data is obtained.

[0080] Exemplarily, the preset pressure sub-model is:

[0081] where TMp is the target return air pressure data, Hp is the exhaust pressure data, Lp is the suction pressure data, β is the first constant, and δ is the second constant.

[0082] Among them, the first constant and the second constant are empirical constants obtained by fitting test data. Different operating conditions (such as operating frequency and ambient temperature) correspond to different parameter values.

[0083] Step S320: Obtain the pressure difference and the pressure difference change rate according to the target return air pressure data and the return air pressure data.

[0084] Among them, the pressure difference is obtained by performing a difference operation on the return air pressure data and the target return air pressure data. The pressure difference change rate is obtained by performing a difference operation on the current pressure difference and the previous pressure difference.

[0085] Exemplarily, step S320 includes: performing a difference operation on the return air pressure data and the target return air pressure data to obtain the pressure difference; obtaining the current pressure difference and the previous pressure difference, and performing a change rate operation on the current pressure difference and the previous pressure difference to obtain the pressure difference change rate.

[0086] Among them, the current pressure difference refers to the pressure difference detected in the current cycle, and the previous pressure difference refers to the pressure difference detected in the previous cycle.

[0087] For example, perform a difference operation on the return air pressure data detected in the current cycle and the target return air pressure data calculated in the current cycle to obtain the pressure difference corresponding to the current cycle; perform a difference operation on the return air pressure data detected in the previous cycle and the target return air pressure data calculated in the previous cycle to obtain the pressure difference corresponding to the previous cycle.

[0088] Step S330: Based on the preset opening sub-model, process the pressure difference and the pressure difference change rate to obtain the opening data.

[0089] Among them, the preset opening sub-model can be established through historical pressure differences and historical pressure difference change rates.

[0090] By inputting the pressure difference and the pressure difference change rate into the preset opening sub-model for processing, the opening data corresponding to the expansion valve is output.

[0091] Exemplarily, the preset opening sub-model is: P2 = △Mp n *k1 + △Mp c *k2 + k3.

[0092] Wherein, P2 is the opening data, and △Mp n is the pressure difference, and △Mp c is the pressure difference change rate, k1 is the third constant, k2 is the fourth constant, and k3 is the fifth constant. The value ranges of the third constant, the fourth constant, and the fifth constant are between 0 and 5.

[0093] In the above embodiment, by pre-establishing a preset pressure sub-model and a preset opening sub-model, the exhaust pressure data and the suction pressure data are input into the preset pressure sub-model for processing to obtain the target return air pressure data, and the pressure difference and the pressure difference change rate are input into the preset opening sub-model for processing, and then the opening data corresponding to the expansion valve is output. According to the opening data corresponding to the expansion valve, the valve opening action of the expansion valve is executed, thereby realizing the precise adjustment of the opening of the expansion valve, optimizing the operating state of the variable frequency heat pump unit, realizing the efficient energy-saving control of the variable frequency heat pump unit, and keeping the operating state of the variable frequency heat pump unit in the best operating state.

[0094] In one embodiment, as Figure 4 shown, the variable frequency heat pump unit further includes a first heat exchanger, a fan module, and a first temperature sensor. The first heat exchanger is connected to the compressor. The fan module is arranged at the air outlet end of the first heat exchanger. The first temperature sensor is arranged at the air inlet end of the first heat exchanger. The first temperature sensor is used to detect the current ambient temperature of the variable frequency heat pump unit. The variable frequency heat pump control method further includes the steps:

[0095] Step S410, obtaining the current ambient temperature data detected by the first temperature sensor and the suction pressure data detected by the second pressure sensor.

[0096] Wherein, the first heat exchanger may be a condenser. The fan module is used to dissipate heat from the condenser. The first heat exchanger, the compressor, and the expansion valve are connected. The first temperature sensor is used to detect the temperature at the air inlet end of the first heat exchanger, that is, the temperature at the air inlet end of the first heat exchange end is confirmed as the current ambient temperature of the variable frequency heat pump unit.

[0097] Exemplarily, when the variable frequency heat pump unit is in the heating mode, the current ambient temperature is detected in real time through the first temperature sensor and the pressure at the suction end of the compressor is detected in real time through the second pressure sensor, so as to obtain the current ambient temperature data detected in real time by the first temperature sensor and the suction pressure data detected by the second pressure sensor.

[0098] Step S420, obtaining the saturated temperature data of the corresponding refrigerant according to the suction pressure data.

[0099] Among them, a mapping relationship table of the pressure and temperature of the corresponding refrigerant can be established in advance, and then according to the obtained suction pressure data, the corresponding mapping relationship table is queried to obtain the saturated temperature data of the corresponding refrigerant.

[0100] Step S430: Based on a preset speed model, process the saturated temperature data and the current ambient temperature data to obtain the speed data of the corresponding fan module.

[0101] Among them, the preset speed model can be established through historical saturated temperature data and historical current ambient temperature data.

[0102] By inputting the saturated temperature data and the current ambient temperature data into the preset speed model, the speed data of the corresponding fan module is output.

[0103] Step S440: Adjust the speed of the fan module according to the speed data.

[0104] According to the speed data of the corresponding fan module, control the speed action of the fan module, thereby realizing precise adjustment of the speed of the fan module, and further optimizing the operating state of the variable-frequency heat pump unit.

[0105] In the above embodiment, according to the saturated temperature of the refrigerant and the current ambient temperature, the speed of the fan module is intelligently adjusted to achieve efficient energy-saving control of the variable-frequency heat pump unit, so that the operating state of the variable-frequency heat pump unit remains in the best operating state.

[0106] In one embodiment, as Figure 5 shown, the steps of processing the saturated temperature data and the current ambient temperature data based on a preset speed model to obtain the speed data of the corresponding fan module include:

[0107] Step S510: Obtain a first temperature difference and a first temperature difference change rate according to the saturated temperature data and the current ambient temperature data.

[0108] Among them, the first temperature difference is obtained by performing a difference process on the saturated temperature data and the current ambient temperature data. The first temperature difference change rate is obtained by performing a difference process on the current first temperature difference and the previous first temperature difference.

[0109] It should be noted that the first temperature difference in the current instance refers to the temperature difference detected in the current cycle, and the first temperature difference in the previous instance refers to the temperature difference detected in the previous cycle. For example, the saturation temperature data detected in the current cycle and the current ambient temperature data calculated in the current cycle are processed for difference to obtain the first temperature difference corresponding to the current cycle; the saturation temperature data detected in the previous cycle and the current ambient temperature data calculated in the previous cycle are processed for difference to obtain the first temperature difference corresponding to the previous cycle.

[0110] Step S520: Based on a preset rotational speed model, process the first temperature difference and the change rate of the first temperature difference to obtain rotational speed data.

[0111] By inputting the first temperature difference and the change rate of the first temperature difference into the preset rotational speed model for processing, the rotational speed data corresponding to the fan module is output.

[0112] Exemplarily, the preset rotational speed model is: Pr = △T n *kx + △T c *ky + kz.

[0113] Wherein, Pr is the rotational speed data, △T n is the temperature difference, △T c is the change rate of the temperature difference, kx is the sixth constant, ky is the seventh constant, and kz is the eighth constant. The value ranges of the sixth constant, the seventh constant, and the eighth constant are between 0 and 5.

[0114] In the above embodiment, by pre - establishing a rotational speed model, inputting the first temperature difference and the change rate of the first temperature difference into the preset rotational speed model for processing, and then outputting the rotational speed data corresponding to the fan module. According to the rotational speed data of the corresponding fan module, the rotational speed action of the fan module is controlled, thereby realizing precise adjustment of the rotational speed of the fan module, optimizing the operating state of the variable - frequency heat pump unit, achieving efficient energy - saving control of the variable - frequency heat pump unit, and keeping the operating state of the variable - frequency heat pump unit in the best operating state.

[0115] In one embodiment, as Figure 6 shown, the variable - frequency heat pump unit further includes a second heat exchanger and a second temperature sensor; the second heat exchanger is connected to the compressor, the second temperature sensor is arranged at the input end or the output end of the second heat exchanger, and the second temperature sensor is used for detecting the port temperature data of the second heat exchanger; the steps for obtaining the first constant and the second constant include:

[0116] Step S610: Obtain the port temperature data detected by the second temperature sensor.

[0117] Among them, the second heat exchanger can be an evaporator, and the second heat exchanger can be used to connect to a water-using device. The evaporator exchanges heat with the water-using device to adjust the temperature of the water used.

[0118] The first heat exchanger, the second heat exchanger, the compressor, and the expansion valve are connected. The second temperature sensor is used to detect the port temperature data of the second heat exchanger. For example, second temperature sensors are respectively arranged at the input end and the output end of the second heat exchanger, and the port temperature data can be the temperature of the input end or the output end of the second heat exchanger.

[0119] Step S620: Obtain the second temperature difference and the second temperature difference change rate based on the port temperature data and the preset temperature threshold.

[0120] Among them, the second temperature difference is obtained by performing a difference operation on the port temperature data and the preset temperature threshold. The second temperature difference change rate is obtained by performing a difference operation on the current second temperature difference and the previous second temperature difference.

[0121] It should be noted that the current second temperature difference refers to the second temperature difference detected in the current cycle, and the previous second temperature difference refers to the second temperature difference detected in the previous cycle. For example, perform a difference operation on the port temperature data detected in the current cycle and the preset temperature threshold calculated in the current cycle to obtain the second temperature difference corresponding to the current cycle; perform a difference operation on the port temperature data detected in the previous cycle and the preset temperature threshold calculated in the previous cycle to obtain the second temperature difference corresponding to the previous cycle.

[0122] Step S630: Obtain the operating frequency of the compressor based on the second temperature difference and the second temperature difference change rate.

[0123] For example, an operating frequency model can be established in advance. By inputting the second temperature difference and the second temperature difference change rate into the preset frequency model, the operating frequency corresponding to the compressor can be output.

[0124] Step S640: Query the first preset mapping relationship table based on the operating frequency and the current ambient temperature to obtain the first constant.

[0125] Among them, the first preset mapping relationship table can be established through corresponding historical test data.

[0126] For example, the first preset relationship table is shown as follows:

[0127]

[0128] The above table uses MPa as the unit for the pressure value.

[0129] Step S650: Query the second preset mapping relation table according to the operating frequency and the current ambient temperature to obtain a second constant.

[0130] Among them, the second preset mapping relation table can be established through corresponding historical test data.

[0131] For example, the second preset relation table is shown as follows:

[0132]

[0133] The above table uses MPa as the unit for the pressure value.

[0134] It should be understood that although Figures 2 to 6 the steps in the flowchart of Figures 2 to 6 are shown in sequence according to the indication of the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise clearly stated in this article, the execution of these steps has no strict order limit, and these steps can be executed in other orders. Moreover,

[0135] In one embodiment, the embodiment of the present invention further provides a variable-frequency heat pump control device, including:

[0136] A pressure acquisition unit for acquiring the port pressure data detected by the pressure sensing module;

[0137] An opening acquisition unit for processing the port pressure data based on a preset opening pressure model to obtain the opening data of the corresponding expansion valve;

[0138] An opening adjustment unit for adjusting the opening of the expansion valve according to the opening data.

[0139] For the specific limitations of the variable-frequency heat pump control device, reference can be made to the limitations on the variable-frequency heat pump control method in the above text, which will not be elaborated here. Each module in the above variable-frequency heat pump control device can be implemented in whole or in part by software, hardware, and their combination. The above-mentioned modules can be embedded in or independent of the control device in the variable-frequency heat pump system in the form of hardware, or stored in the memory of the variable-frequency heat pump system in the form of software, so that the control device can call and execute the operations corresponding to the above-mentioned modules.

[0140] In one embodiment, as Figure 7As shown in the figure, a variable frequency heat pump system is also provided, which includes a control device 710 and a variable frequency heat pump unit 720; the control device 710 is connected to the variable frequency heat pump unit 720; the control device 710 is used to execute the steps of the variable frequency heat pump control method described in any one of the above.

[0141] Among them, the variable frequency heat pump unit 720 includes a compressor, an expansion valve and a pressure sensing module. The compressor is connected to the expansion valve. The pressure sensing module is used to detect the port pressure data of the compressor. The control device is respectively connected to the compressor, the expansion valve and the pressure sensing module.

[0142] Among them, the control device 710 can be used to execute the steps of the following water use control method:

[0143] Obtain the port pressure data detected by the pressure sensing module; based on a preset opening model, process the port pressure data to obtain the opening data corresponding to the expansion valve; according to the opening pressure data, adjust the opening of the expansion valve to achieve efficient energy-saving control of the variable frequency heat pump unit.

[0144] In the above embodiment, according to the port pressure of the compressor, the opening of the expansion valve is intelligently adjusted to adjust the operating state of the variable frequency heat pump unit, so that the operating state of the variable frequency heat pump unit remains in the best operating state.

[0145] In one embodiment, as Figure 8 shown in the figure, the variable frequency heat pump system further includes a water use device 740; the variable frequency heat pump unit 720 includes a compressor 722, an expansion valve 724, a first heat exchanger 726, a second heat exchanger 728 and a pressure sensing module 732; the compressor 722, the expansion valve 724, the first heat exchanger 726 and the second heat exchanger 728 are connected to form a refrigerant circulation path; the second heat exchanger 728 is connected to the water use device 740 to form a water temperature adjustment path; the pressure sensing module 732 is arranged at the port of the compressor 722; the control device 710 is respectively connected to the compressor 722, the expansion valve 724 and the pressure sensing module 732.

[0146] Among them, the second heat exchanger 728 can be a plate-shaped, sleeve-shaped or shell-and-tube heat exchanger. The water use device 740 includes an inlet passage and an outlet passage. The inlet passage is provided with a water pump, a water flow switch and a second temperature sensor for detecting the inlet water temperature; the outlet passage is provided with a water pressure sensor, an exhaust valve and a second temperature sensor for detecting the outlet water temperature. Water enters the second heat exchanger through the inlet passage for heat exchange, and the heat-exchanged water is output through the outlet passage, thereby realizing the temperature adjustment of the water.

[0147] For example, when using water for refrigeration, the compressor 722 compresses and boosts the low-temperature and low-pressure gas from the second heat exchanger 728 into a high-temperature and high-pressure liquid, consuming electrical energy during compression. The high-temperature and high-pressure liquid enters the first heat exchanger 726, releases heat and liquefies into a medium-temperature and high-pressure liquid. The heat released during liquefaction is discharged to the external medium through heat exchange. The medium-temperature and high-pressure liquid enters the expansion valve 724, throttles and reduces the pressure to a low-temperature and low-pressure liquid. The low-temperature and low-pressure liquid enters the second heat exchanger 728, absorbs heat and vaporizes into a low-temperature and low-pressure gas. The heat absorbed during vaporization is obtained from the water-using device 740 through heat exchange, thereby refrigerating the water used. The low-temperature and low-pressure gas enters the compressor 722 again, starting the next refrigeration cycle, and continuously refrigerating the water used in this way.

[0148] When using water for heating, the compressor 722 compresses and boosts the low-temperature and low-pressure gas from the first heat exchanger 726 into a high-temperature and high-pressure liquid, consuming electrical energy during compression. The high-temperature and high-pressure liquid enters the second heat exchanger 728, releases heat and liquefies into a medium-temperature and high-pressure liquid. The heat released during liquefaction is discharged to the water-using device 740 through heat exchange, thereby refrigerating the water used. The medium-temperature and high-pressure liquid enters the expansion valve 724, throttles and reduces the pressure to a low-temperature and low-pressure liquid. The low-temperature and low-pressure liquid enters the first heat exchanger 726, absorbs heat and vaporizes into a low-temperature and low-pressure gas. The heat absorbed during vaporization is obtained from the external medium through heat exchange. The low-temperature and low-pressure gas enters the compressor 722 again, starting the next heating cycle, and continuously heating the water used in this way.

[0149] In one example, as Figure 8 shown, the variable-frequency heat pump unit further includes a four-way valve, a gas-liquid separator, and an oil separator; the four-way valve is respectively connected to the gas-liquid separator, the oil separator, the first heat exchanger, and the second heat exchanger. The gas-liquid separator is connected to the suction end of the compressor, and the oil separator is connected to the discharge end of the compressor.

[0150] Among them, the four-way valve is used to change the flow direction of the refrigerant and realize the switching between the refrigeration and heating modes; the gas-liquid separator is used to separate the gas and liquid in the refrigerant to ensure that they enter the corresponding pipelines respectively; the oil separator can separate the oil in the gas discharged from the compressor crankcase, reduce the discharge of oil from the crankcase breather to the outside of the engine, and improve the service life of the compressor.

[0151] In one example, as Figure 8 shown, the variable-frequency heat pump unit further includes an economizer, and the economizer is connected between the suction end of the compressor and the expansion valve.

[0152] The economizer is achieved by reducing the temperature and pressure inside the compressor. After the high-pressure liquid refrigerant enters the economizer, a part of it throttles through the corresponding expansion valve and is further cooled in the way of heat expansion to reduce the temperature of the other part and make it subcooled. The subcooled liquid enters the evaporator for refrigeration, while the uncooled gaseous refrigerant re-enters the compressor through the connecting pipe between the economizer and the compressor to continue compression. The economizer reduces the temperature and pressure inside the compressor, reduces the energy consumption and loss of the compressor, and thus improves the overall efficiency of the variable-frequency heat pump unit.

[0153] In one embodiment, a computer-readable storage medium is further provided, on which a computer program is stored. When the computer program is executed by a processor, the steps of the variable-frequency heat pump control method in any one of the above are realized.

[0154] In one example, when the computer program is executed by a processor, the following steps are realized:

[0155] Obtain the port pressure data detected by the pressure sensing module; process the port pressure data based on the preset opening model to obtain the opening data of the corresponding expansion valve; adjust the opening of the expansion valve according to the opening pressure data to realize the efficient energy-saving control of the variable-frequency heat pump unit.

[0156] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above methods. Among them, any reference to the memory, storage, database or other media used in the various embodiments provided in the present application can include non-volatile and / or volatile memories. The non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. The volatile memory can include random access memory (RAM) or an external cache. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), direct memory bus DRAM (DRDRAM), and memory bus DRAM (RDRAM), etc.

[0157] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as within the scope described in this specification.

[0158] The above-described embodiments merely represent several implementation manners of the present application. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the appended claims.

Claims

1. A variable frequency heat pump control method, characterized in that: Applied to a variable frequency heat pump unit, the variable frequency heat pump unit includes a compressor, an expansion valve and a pressure sensing module, the compressor is connected to the expansion valve, and the pressure sensing module is used to detect the port pressure data of the compressor; the variable frequency heat pump control method includes the following steps: Acquiring port pressure data detected by the pressure sensing module; Based on a preset opening pressure model, the port pressure data is processed to obtain the opening data corresponding to the expansion valve; The opening degree of the expansion valve is adjusted according to the opening degree data.

2. The variable frequency heat pump control method according to claim 1, characterized in that: The pressure sensing module includes a first pressure sensor, a second pressure sensor and a third pressure sensor; the first pressure sensor is used to detect the exhaust pressure data of the exhaust end of the compressor, the second pressure sensor is used to detect the suction pressure data of the suction end of the compressor, and the third pressure sensor is used to detect the return pressure data of the return end of the compressor; The step of processing the port pressure data based on a preset opening pressure model to obtain the opening data corresponding to the expansion valve comprises: Based on a preset opening pressure model, the exhaust pressure data, the intake pressure data and the return pressure data are processed to obtain the opening data corresponding to the expansion valve.

3. The variable frequency heat pump control method according to claim 2, characterized in that: The step of processing the exhaust pressure data, the intake pressure data and the return pressure data based on the preset opening pressure model to obtain the opening data corresponding to the expansion valve includes: Based on a preset pressure sub-model, the exhaust pressure data and the intake pressure data are processed to obtain target return air pressure data; Obtaining a pressure difference and a pressure difference change rate according to the target return air pressure data and the return air pressure data; Based on a preset opening degree sub-model, the pressure difference and the pressure difference change rate are processed to obtain the opening degree data.

4. The variable frequency heat pump control method according to claim 3, characterized in that: The preset pressure sub-model is: in, is the target return air pressure data, is the exhaust pressure data, is the inspiratory pressure data, is the first constant, is the second constant.

5. The variable frequency heat pump control method according to claim 3, characterized in that: The step of obtaining the pressure difference and the pressure difference change rate according to the target return air pressure data and the return air pressure data comprises: Performing difference processing on the return air pressure data and the target return air pressure data to obtain the pressure difference; The current pressure difference value and the previous pressure difference value are obtained, and the change rate of the current pressure difference value and the previous pressure difference value is processed to obtain the pressure difference change rate.

6. The variable frequency heat pump control method according to claim 5, characterized in that: The preset opening sub-model is: in, is the opening data, is the pressure difference, is the pressure difference change rate, is the third constant, is the fourth constant, is the fifth constant.

7. The variable frequency heat pump control method according to claim 4, characterized in that: The variable frequency heat pump unit also includes a first heat exchanger, a fan module and a first temperature sensor, the first heat exchanger is connected to the compressor, the fan module is arranged at the air outlet end of the first heat exchanger, the first temperature sensor is arranged at the air inlet end of the first heat exchanger, and the first temperature sensor is used to detect the current ambient temperature of the variable frequency heat pump unit; the variable frequency heat pump control method also includes the steps of: Acquiring current ambient temperature data detected by the first temperature sensor and suction pressure data detected by the second pressure sensor; According to the suction pressure data, saturation temperature data of the corresponding refrigerant is obtained; Based on a preset speed model, the saturation temperature data and the current ambient temperature data are processed to obtain speed data corresponding to the fan module; The rotation speed of the fan module is adjusted according to the rotation speed data.

8. The variable frequency heat pump control method according to claim 7, characterized in that: The step of processing the saturation temperature data and the current ambient temperature data based on a preset speed model to obtain the speed data corresponding to the fan module includes: Obtaining a first temperature difference and a first temperature difference change rate according to the saturation temperature data and the current ambient temperature data; Based on a preset rotation speed model, the first temperature difference and the first temperature difference change rate are processed to obtain the rotation speed data.

9. The variable frequency heat pump control method according to claim 8, characterized in that: The preset speed model is: in, is the speed data, is the temperature difference, is the temperature difference change rate, is the sixth constant, is the seventh constant, is the eighth constant.

10. The variable frequency heat pump control method according to claim 8, characterized in that: The variable frequency heat pump unit further includes a second heat exchanger and a second temperature sensor; the second heat exchanger is connected to the compressor, the second temperature sensor is arranged at the input end or the output end of the second heat exchanger, and the second temperature sensor is used to detect the port temperature data of the second heat exchanger; the steps of obtaining the first constant and the second constant include: Acquiring port temperature data detected by the second temperature sensor; A second temperature difference and a second temperature difference change rate obtained according to the port temperature data and a preset temperature threshold; obtaining an operating frequency of the compressor according to the second temperature difference and a change rate of the second temperature difference; According to the operating frequency and the current ambient temperature, query a first preset mapping relationship table to obtain the first constant; According to the operating frequency and the current ambient temperature, a second preset mapping relationship table is queried to obtain the second constant.

11. A variable frequency heat pump system, characterized in that: It includes a control device and a variable frequency heat pump unit; the control device is connected to the variable frequency heat pump unit; The control device is used to execute the steps of the variable frequency heat pump control method according to any one of claims 1 to 10.

12. The variable frequency heat pump system according to claim 11, characterized in that: The variable frequency heat pump system also includes a water-using device; the variable frequency heat pump unit includes a compressor, an expansion valve, a first heat exchanger, a second heat exchanger and a pressure sensing module; the compressor, the expansion valve, the first heat exchanger and the second heat exchanger are connected to form a refrigerant circulation path; the second heat exchanger is connected to the water-using device to form a water temperature adjustment path; the pressure sensing module is arranged at the port of the compressor; The control device is respectively connected to the compressor, the expansion valve and the pressure sensing module.

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