Method for determining frequency of compressor of heat pump system and heat pump control system

Abstract

The invention discloses a method for determining the frequency of a compressor of a heat pump system and a heat pump control system. The method comprises the steps that the field environment temperature for heating a target medium through the heat pump system is obtained; target working condition parameters are called in a preset database according to the field environment temperature, the target working condition parameters are corresponding working condition parameters when the efficiency index of the heat pump system at the field environment temperature reaches a preset requirement, and the working condition parameters comprise at least one of the expansion valve opening degree, the CO2 refrigerant flow, the evaporator inlet temperature and the evaporator outlet temperature; the target working condition parameters are input into a preset mathematical model, and compressor work is obtained through calculation; and the operation frequency of the compressor in the heat pump system is determined according to acting of the compressor. According to the method, the corresponding working condition parameters are called in the existing database through the field environment temperature obtained in real time, the compressor frequency meeting the performance index is calculated through the working condition parameters, and then efficient and accurate control over the heat pump system is achieved.

Description

Technical Field

[0001] The present application belongs to the technical field of heat pumps, and in particular, relates to a method for determining a compressor frequency of a heat pump system and a heat pump control system. Background Art

[0002] CO2 heat pump systems are widely used to heat fluid media due to their good high temperature performance and environmental protection characteristics. In this process, the system can achieve efficient operation and precise temperature regulation by controlling the compressor.

[0003] However, the existing compressor frequency control strategy mostly relies on the Proportional-Integral-Derivative Algorithm (PID algorithm). Its control rules are relatively complex, the parameter setting is difficult, the programming logic judgment of the program block is cumbersome, which is not conducive to fast execution, and the actual adjustment process lacks intuitive analysis, making it difficult to adjust the system parameters efficiently and accurately, thus affecting the overall operating efficiency of the CO2 heat pump system. Summary of the invention

[0004] The embodiments of the present application provide a method for determining the compressor frequency of a heat pump system and a heat pump control system, which can improve the operating efficiency of the CO2 heat pump system.

[0005] In a first aspect, an embodiment of the present application provides a method for determining a compressor frequency of a heat pump system, the method comprising:

[0006] Obtain the on-site ambient temperature of the target medium heated by the heat pump system;

[0007] According to the on-site ambient temperature, the target operating condition parameters are called in the preset database. The target operating condition parameters are the operating condition parameters corresponding to when the efficiency index of the heat pump system reaches the preset requirements at the on-site ambient temperature. The operating condition parameters include at least one of the expansion valve opening, CO2 refrigerant flow, evaporator inlet temperature, and evaporator outlet temperature;

[0008] Input the target operating condition parameters into the preset mathematical model to calculate the work done by the compressor;

[0009] The operating frequency of the compressor in the heat pump system is determined based on the work done by the compressor.

[0010] In a possible implementation manner of the first aspect, after determining the operating frequency of the compressor in the heat pump system according to the work done by the compressor, the method further includes:

[0011] Collect the outlet temperature of the target medium in the heat pump system;

[0012] Calculate the temperature difference between the outlet temperature and the target outlet temperature;

[0013] According to the temperature difference, the operating frequency of the compressor is adjusted.

[0014] In a possible implementation manner of the first aspect, adjusting the operating frequency of the compressor according to the temperature difference includes:

[0015] When the temperature difference is less than the first threshold, increasing the operating frequency of the compressor by a first step;

[0016] When the temperature difference is greater than or equal to the first threshold value and less than the second threshold value, the operating frequency of the compressor is increased by a second step length, and the second step length is smaller than the first step length;

[0017] When the temperature difference is greater than or equal to the third threshold value and less than the fourth threshold value, reducing the operating frequency of the compressor by a third step length;

[0018] When the temperature difference is greater than or equal to a fourth threshold, the operating power of the compressor is reduced by a fourth step length, and the fourth step length is greater than the third step length.

[0019] In a possible implementation manner of the first aspect, the method further includes:

[0020] After adjusting the operating power of the compressor, the temperature difference is cyclically determined at intervals of a first preset period, and the step of adjusting the operating frequency of the compressor according to the temperature difference is continued.

[0021] In a possible implementation of the first aspect, the preset mathematical model includes a first model and a second model, and the target operating condition parameter is input into the preset mathematical model to calculate the compressor performance, and the method includes:

[0022] Obtain the flow value, inlet temperature and outlet temperature of the target medium in the heat pump system;

[0023] Using the first model, the required heating amount of the target medium is calculated based on the flow value, the inlet temperature and the outlet temperature;

[0024] Using the second model, the heat absorbed by the evaporator is calculated according to the operating parameters;

[0025] The work done by the compressor is determined based on the required heating amount of the target medium and the heat absorbed by the evaporator.

[0026] In a possible implementation manner of the first aspect, the preset database includes a mapping relationship between the ambient temperature, an efficiency index of the heat pump system, and operating parameters.

[0027] In a possible implementation manner of the first aspect, calling a target operating condition parameter in a preset database according to the on-site ambient temperature, the method includes:

[0028] When the preset database does not contain the on-site ambient temperature, the target operating condition parameters corresponding to the on-site ambient temperature are calculated using the interpolation method based on the operating condition parameters corresponding to the ambient temperatures adjacent to the on-site ambient temperature in the preset database.

[0029] In a second aspect, an embodiment of the present application provides a device for determining a compressor frequency of a heat pump system, the device comprising:

[0030] An acquisition module, used to acquire the on-site ambient temperature of a target medium heated by a heat pump system;

[0031] A calling module is used to call the target operating condition parameters in the preset database according to the on-site ambient temperature. The target operating condition parameters are the operating condition parameters corresponding to when the efficiency index of the heat pump system meets the preset requirements at the on-site ambient temperature. The operating condition parameters include at least one of the expansion valve opening, CO2 refrigerant flow, evaporator inlet temperature, and evaporator outlet temperature;

[0032] A calculation module, used to input the target operating condition parameters into a preset mathematical model to calculate the work done by the compressor;

[0033] The processing module is used to determine the operating frequency of the compressor in the heat pump system according to the work done by the compressor.

[0034] In a fourth aspect, an embodiment of the present application provides a heat pump control system, which includes: a heat pump system and a control device, the heat pump system includes at least a compressor, and the control device is used to execute any one of the methods in the first aspect above.

[0035] In a fifth aspect, an embodiment of the present application provides a computer device, comprising: a processor, and a memory storing computer program instructions; the processor reads and executes the computer program instructions to implement any one of the methods in the first aspect above.

[0036] In a sixth aspect, an embodiment of the present application provides a computer-readable storage medium having computer program instructions stored thereon, and when the computer program instructions are executed by a processor, the method of any one of the above-mentioned first aspects is implemented.

[0037] In a seventh aspect, an embodiment of the present application provides a computer program product, which includes a computer program, and when the computer program is executed by a processor, it implements any one of the methods in the above-mentioned first aspect.

[0038] The technical solution provided by the embodiments of the present application brings at least the following beneficial effects:

[0039] The method for determining the compressor frequency of a heat pump system provided in an embodiment of the present application matches the operating parameters in the database that meet the system efficiency index requirements according to the actual ambient temperature at the heating site, and calculates the compressor work in combination with a preset mathematical model to ultimately determine the compressor operating frequency. This solution abandons the complex rule establishment and cumbersome logical judgment in traditional PID control, significantly simplifies the control process through a data-driven approach, and improves the system response speed and execution efficiency. At the same time, the control method based on the database and mathematical model makes the adjustment process more intuitive and transparent, facilitates the precise optimization of system parameters, and thus effectively adapts to a variety of operating conditions, significantly improving the operating efficiency, stability, and energy-saving effects of the heat pump system. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solution of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application.

[0041] Figure 1 It is a scenario schematic diagram of a method for determining the compressor frequency of a heat pump system provided in an embodiment of the present application;

[0042] Figure 2 It is a flow chart of a method for determining the compressor frequency of a heat pump system provided in an embodiment of the present application;

[0043] Figure 3 It is a flow chart of a method for determining the compressor frequency of a heat pump system provided in an embodiment of the present application;

[0044] Figure 4 It is a structural schematic diagram of a device for determining the compressor frequency of a heat pump system provided in an embodiment of the present application;

[0045] Figure 5 It is a structural schematic diagram of a heat pump control system provided in an embodiment of the present application;

[0046] Figure 6 is a structural schematic diagram of a heat pump system provided in an embodiment of the present application;

[0047] Figure 7 It is a structural diagram of a computer device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0048] In order to make those of ordinary skill in the art better understand the technical scheme of the present application, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only intended to explain the present application, rather than to limit the present application. For those skilled in the art, the present application can be implemented without the need for some of these specific details. The following description of the embodiments is only to provide a better understanding of the present application by illustrating the examples of the present application.

[0049] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here can be implemented in an order other than those illustrated or described here. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. On the contrary, they are only examples consistent with some aspects of the present application as detailed in the attached claims.

[0050] As mentioned in the background technology section, in the industrial production process, some fluids often need to be heated. For example, in the field of heated medium transportation, the heated medium must be heated before transportation due to its high viscosity. CO2 heat pumps have the advantages of high heating capacity at high temperatures and high heating performance at low ambient temperatures, and are widely used in the field of industrial heating.

[0051] The existing CO2 heat pump compressor control strategy adopts general PID algorithm and fuzzy PID algorithm. The general PID algorithm consists of three control units, execution module, operation object construction, and then adding feedback loop to form a PID controller model. The fuzzy PID algorithm evolved from the general PID algorithm. Through data modeling, the deviation value (E) and the deviation change rate (EC) between the feedback value and the set value are analyzed to establish two-dimensional fuzzy control rules for proportional, integral and differential factors respectively. The three parameters of PID are dynamically adjusted within a certain range, so that the PID controller can be applied to the environment where the heating load conditions are constantly changing. The CO2 heat pump system is adjusted in a steady state and the operating conditions will not change significantly.

[0052] However, in practical applications, fuzzy PID control rules are complex and difficult to establish, the logic judgment of program blocks is cumbersome and not conducive to rapid execution, and the actual adjustment process is not intuitive and analytical, which cannot meet the needs of simple and rapid adjustment of compressor frequency.

[0053] In order to solve the above technical problems, the present application proposes a method for determining the compressor frequency of a heat pump system and a heat pump control system.

[0054] Figure 1A schematic diagram of an application scenario of a method for determining the compressor frequency of a heat pump system provided in an embodiment of the present application is shown.

[0055] like Figure 1 As shown in the figure, the scenario includes a temperature sensor, a database, and a processor. This solution uses a temperature sensor to obtain the on-site inlet temperature, outlet temperature, and on-site ambient temperature of the target medium transported by the heat pump heating technology in real time, and calls the target parameters based on the database. The processor uses the target parameters and the on-site inlet temperature and outlet temperature of the target medium to calculate the compressor frequency that meets the performance indicators, thereby achieving efficient and accurate control of the heat pump system.

[0056] The method for determining the compressor frequency of the heat pump system provided in the embodiment of the present application is described in detail below through specific embodiments in conjunction with the accompanying drawings.

[0057] Figure 2 A flow chart of a method for determining the compressor frequency of a heat pump system provided in an embodiment of the present application is shown.

[0058] like Figure 2 As shown, the method may include the following steps.

[0059] S210: Acquire the on-site ambient temperature of the target medium heated by the heat pump system.

[0060] The heat pump system is a highly efficient heat energy conversion device that drives the compressor to work by inputting a small amount of electrical energy, absorbing heat from a low-temperature heat source and releasing heat to a high-temperature heat source.

[0061] For example, the heat pump system in this embodiment can be limited to a CO2 heat pump system. The CO2 heat pump system uses carbon dioxide as a working fluid, has the characteristics of high environmental protection and excellent performance under high temperature conditions, and is particularly suitable for high temperature heating scenarios. However, when the CO2 heat pump system is operating at high temperatures, due to the complex working fluid characteristics and high system pressure, the frequency control of its compressor is difficult, and traditional control methods are difficult to achieve precise regulation.

[0062] The target medium is the medium heated by the heat pump system.

[0063] Exemplarily, the purpose of heating the target medium is to convert it from a solid or high-viscosity state to a fluid state for subsequent transportation.

[0064] As an example but not limitation, the target medium may be crude oil produced from mining, which is usually highly viscous or semi-solid at room temperature and needs to be heated to reduce viscosity in order to improve fluidity.

[0065] It is important to understand that the core goal of the heat pump system to heat the target medium is to make it reach the set outlet temperature. To achieve this goal, the compressor frequency of the heat pump system needs to be dynamically adjusted according to the on-site ambient temperature, and the target medium is heated to the preset outlet temperature through the work of the compressor. Therefore, when the heat pump system is used to heat the target medium to make it a fluid state, the on-site ambient temperature needs to be collected in real time.

[0066] S220. Calling target operating condition parameters from a preset database according to the on-site ambient temperature.

[0067] The preset database is a pre-built database storing the operation data of the heat pump system under different ambient temperatures.

[0068] Exemplarily, the heat pump system operating data includes, but is not limited to, efficiency indicators and key operating parameters of the heat pump system.

[0069] In one implementation, a preset database establishes a mapping relationship between ambient temperature, heat pump system efficiency index, and operating parameters.

[0070] In another implementation, the preset database directly stores the mapping relationship between the ambient temperature and the corresponding operating parameters when the efficiency index of the heat pump system reaches the preset requirements.

[0071] Operating parameters refer to the key variables that affect the operating status of the heat pump system.

[0072] Exemplarily, the operating parameters include but are not limited to at least one of the expansion valve opening, CO2 refrigerant flow, evaporator inlet temperature, and evaporator outlet temperature. These parameters determine the operating efficiency of the heat pump system and the heating effect of the target medium.

[0073] The target operating parameters are the operating parameters corresponding to when the efficiency index of the heat pump system reaches the preset requirements under the on-site ambient temperature.

[0074] For example, the efficiency index can be measured by COP (Coefficient of Performance). Correspondingly, the efficiency index meeting the preset requirement can mean that the COP reaches the highest value, that is, the system energy efficiency is optimal.

[0075] In one implementation, the preset database is constructed based on experimental data. By collecting system operation data at different ambient temperatures and different target outlet temperatures, the operating parameters (such as expansion valve opening, CO2 refrigerant flow, evaporator inlet temperature, evaporator outlet temperature, etc.) when the system COP reaches the highest are analyzed, and these parameters are classified and stored according to ambient temperature and target outlet temperature to form a data table.

[0076] Table 1 shows an example of the operating condition parameters corresponding to the optimal COP of the heat pump system at different ambient temperatures when the target medium outlet temperature is 50°C.

[0077]

[0078]

[0079] As can be seen from the above table, when the target outlet temperature of the target medium is 50°C, at different ambient temperatures, the specific values of the operating condition parameters such as the expansion valve opening, CO2 refrigerant flow rate, evaporator inlet temperature, and evaporator outlet temperature corresponding to the optimal efficiency index of the heat pump system.

[0080] In actual operation, the outlet temperature of the target medium is usually fixed, but the outlet temperatures of different target media may be different. Therefore, this step can be further refined as follows:

[0081] S221. Determine the target outlet temperature of the target medium.

[0082] Set its target outlet temperature according to the characteristics of the target medium (such as the fluidity requirement of crude oil).

[0083] S222. Call the target operating condition parameters in the preset database according to the on-site ambient temperature and the target outlet temperature.

[0084] Combined with the ambient temperature and the target outlet temperature, query the preset database to obtain the operating condition parameters corresponding to the optimal COP of the system.

[0085] For example, assume that the current ambient temperature is T1, and when 10°C < T1 < 12°C, set the target outlet temperature to 50°C. The following table is obtained by querying the database. Table 2 shows the target operating condition parameters corresponding to the ambient temperatures of 10°C and 12°C at the target outlet temperature of 50°C.

[0086]

[0087] The data at the current ambient temperature is obtained through calculation and analysis:

[0088] Expansion valve opening EVE = (T1 - 10) * (EVE12 - EVE10) / 2 + EVE10.

[0089] CO2 refrigerant flow rate F = (T1 - 10) * (F12 - F10) / 2 + F10.

[0090] Evaporator inlet temperature Tein = (T1 - 10) * (Tin12 - Tin10) / 2 + Tin10.

[0091] Evaporator outlet temperature Teout = (T1-10)*(Tout12-Tout10) / 2+Tout10.

[0092] As can be seen from the above, the core of this step is to query the operating parameters corresponding to the optimal efficiency index of the heat pump system under the on-site ambient temperature collected in step S210 in the preset database. This method realizes the intelligent call of the operating parameters of the heat pump system, avoids the complex rule establishment and parameter setting process in the traditional control method, and significantly improves the control accuracy and operation efficiency of the system. At the same time, the preset database based on experimental data ensures the optimal operating state of the system under different ambient temperatures and target outlet temperatures, providing reliable technical support for the efficient and stable operation of the heat pump system.

[0093] In one embodiment, when the preset database does not contain the collected on-site ambient temperature, the target operating condition parameters are calculated using an interpolation method based on the operating condition parameters corresponding to the ambient temperatures adjacent to the on-site ambient temperature in the preset database.

[0094] This means that when the ambient temperature collected on site is missing, the known temperature data adjacent to the target ambient temperature can be searched in the database. For example, if the target temperature is between two known temperature values, these two adjacent temperature points are selected as the benchmark. The target operating parameters under the target temperature (i.e., the on-site ambient temperature) are calculated using an interpolation method (such as linear interpolation or polynomial interpolation).

[0095] This solution calculates the target operating parameters through interpolation. When the on-site ambient temperature data is missing, it can be extrapolated based on the operating parameters of adjacent ambient temperatures, thereby achieving effective estimation of the target operating parameters and improving the adaptability and accuracy of the system under different ambient temperatures.

[0096] S230, inputting the target operating condition parameters into a preset mathematical model to calculate the work done by the compressor.

[0097] In one implementation, the compressor work can be indirectly calculated based on the heat balance relationship. That is, the preset mathematical model is used to calculate the required heating amount of the target medium and the heat absorbed by the evaporator according to the target operating condition data, and then derive the compressor work requirement. The advantage of this method is clear logic and high calculation accuracy, which is suitable for scenarios with high system energy efficiency requirements.

[0098] In one implementation, the compressor work requirement can be directly queried or calculated according to the target operating condition parameters through a preset compressor performance curve. The advantages of this method are simple calculation and high execution efficiency, and it is suitable for scenarios with high real-time requirements.

[0099] S240: Determine the operating frequency of the compressor in the heat pump system according to the work done by the compressor.

[0100] In one implementation, the compressor work is directly converted into operating power through the theoretical efficiency of the compressor, and the compressor operating frequency is further calculated based on the operating power. Its advantages are simple calculation and high execution efficiency, which is suitable for scenarios with high real-time requirements, but it depends on the accuracy of theoretical efficiency.

[0101] In one implementation, the actual operating power is calculated by real-time monitoring of the compressor's current, voltage, and power factor, and the operating frequency is dynamically adjusted according to the compressor's work. Its advantage is that it can respond to system changes in real time, improve energy efficiency, and is suitable for scenarios with high requirements for operating efficiency.

[0102] In one implementation, the compressor frequency curve is constructed through experimental data or performance parameters provided by the manufacturer, and the corresponding operating frequency is calculated by querying or interpolating the work done by the compressor. Its advantage is high calculation accuracy, which is suitable for scenarios with high control accuracy requirements, but an accurate frequency curve needs to be constructed in advance.

[0103] This application scheme matches the operating parameters in the database that meet the system efficiency index requirements according to the actual ambient temperature, and calculates the compressor work in combination with the preset mathematical model to finally determine the compressor operating frequency. This scheme abandons the complex rule establishment and cumbersome logical judgment in traditional PID control, and significantly simplifies the control process through data-driven methods, improving the system response speed and execution efficiency. At the same time, the control method based on the database and mathematical model makes the adjustment process more intuitive and transparent, and facilitates the precise optimization of system parameters, thereby effectively adapting to various working conditions and significantly improving the operating efficiency, stability and energy-saving effect of the heat pump system.

[0104] In one embodiment, when indirectly calculating the compressor work based on the heat balance relationship, the preset mathematical model may include a first model and a second model.

[0105] The first model is used to calculate the required heating capacity of the target medium.

[0106] The second model is used to calculate the heat absorbed by the evaporator.

[0107] Correspondingly, step S230 may include the following steps:

[0108] S231. Obtain the flow value, inlet temperature, and outlet temperature of the target medium in the heat pump system.

[0109] In the target medium heating system, the flow value (M1), inlet temperature (Tyin) and outlet temperature (Tyout) of the target medium are the key parameters for calculating the heating capacity. The outlet temperature of the target medium is usually set to a fixed value to ensure its fluidity or meet the subsequent process requirements.

[0110] S232: Using the first model, based on the flow value, the inlet temperature and the outlet temperature, the required heating amount of the target medium is calculated.

[0111] Exemplarily, the formula of the first model is as follows:

[0112] Q1=(cp*M1) / 3.6*(Tyout-Tyin); (1)

[0113] Wherein, Q1 is the required heating capacity of the target medium (kW), cp is the specific heat capacity of the target medium (kJ / kg / K), M1 is the flow value of the target medium (kg / h), Tyin is the inlet temperature of the target medium (℃), and Tyout is the outlet temperature of the target medium (℃).

[0114] In the target medium heating system, the target value of the target medium outlet temperature is relatively constant, and the required heating capacity of the target medium is relatively constant by default. The required heating capacity of the target medium is calculated based on the target medium flow value, target medium inlet temperature, and target medium outlet temperature in the pipeline.

[0115] S233. Using the second model, according to the target operating parameters, calculate the heat absorbed by the evaporator.

[0116] Exemplarily, the formula of the second model is as follows:

[0117] Q2=Mco2△h;(2)

[0118] Among them, Q2 is the heat absorbed by the evaporator, Mco2 is the CO2 refrigerant flow rate F, and △h is the enthalpy difference of the CO2 refrigerant at the inlet and outlet of the evaporator.

[0119] △h=Cp1*Tein-Cp2*Teout; (3)

[0120] Among them, Cp1 is the constant-pressure specific heat capacity of CO2 at the evaporator inlet, Cp2 is the constant-pressure specific heat capacity of CO2 at the evaporator outlet, Tein and Teout represent the temperature values ​​of the evaporator inlet and outlet respectively.

[0121] Ignoring the heat transfer loss of the evaporator, the absorbed heat Q2 of the evaporator is calculated using the above formula.

[0122] S234. Determine the work done by the compressor according to the required heating amount of the target medium and the heat absorbed by the evaporator.

[0123] The energy sources of the CO2 heat pump system include the heat absorbed by the evaporator from the air and the heat energy of the compressor. According to the first law of thermodynamics (assuming that heat loss is not considered), the energy balance relationship of the CO2 heat pump system is:

[0124] Q1=Q2+W3; (4)

[0125] Among them, Q1 is the heating amount required by the target medium, Q2 is the heat absorbed by the evaporator, and W3 is the work done by the compressor.

[0126] Through the above formula, the work requirement of the compressor can be derived:

[0127] W3=Q1-Q2; (5)

[0128] Thus, the work done by the compressor of the heat pump system is obtained.

[0129] This embodiment indirectly calculates the work done by the compressor through the heat balance relationship, and then obtains the compressor operating frequency, which is suitable for high-precision scenarios. Specifically, by using a preset mathematical model, combined with the flow rate, temperature and other operating parameters of the target medium, the required heating amount and the heat absorbed by the evaporator are accurately calculated. Through these calculation results, the working state of the compressor can be determined more accurately.

[0130] Figure 3 A flow chart of a method for determining the compressor frequency of a heat pump system provided in an embodiment of the present application is shown.

[0131] It should be understood that Figure 3 The embodiment shown can be regarded as Figure 2 Further optimization of the embodiment, that is, in Figure 2 Based on the compressor frequency calculated by the embodiment, the outlet temperature of the target medium is monitored in real time to dynamically fine-tune the operating frequency of the compressor to achieve more accurate temperature control and higher system stability.

[0132] like Figure 3 As shown, in addition to steps S210 - S240 , this embodiment may also include the following steps.

[0133] S310: Collect the outlet temperature of the target medium in the heat pump system.

[0134] The outlet temperature of the target medium is collected in real time as a feedback signal of the system operation status. The outlet temperature of the target medium is a key indicator to measure the heating effect of the heat pump system.

[0135] S320, calculating the temperature difference between the outlet temperature and the target outlet temperature.

[0136] By comparing the actual outlet temperature of the target medium with the preset target outlet temperature, the temperature difference (△T) between the two is calculated. The temperature difference reflects the deviation between the current operating state of the system and the target state.

[0137] S330: Adjust the operating frequency of the compressor according to the temperature difference.

[0138] According to the size of the temperature difference, the operating frequency of the compressor is dynamically adjusted using a step-by-step adjustment strategy, which specifically includes the following sub-steps:

[0139] S331. When the temperature difference is less than a first threshold, increase the operating frequency of the compressor by a first step.

[0140] When the temperature difference is large and negative (i.e. the actual temperature is much lower than the target temperature), the operating frequency of the compressor is increased by a larger step to quickly improve the system heating capacity and make the actual temperature quickly approach the target temperature.

[0141] S332: When the temperature difference is greater than or equal to the first threshold and less than the second threshold, increase the operating power of the compressor by a second step.

[0142] The second step length is smaller than the first step length.

[0143] The first threshold is smaller than the second threshold.

[0144] When the temperature difference is small and negative, the compressor operating frequency is increased by smaller steps to fine-tune the system heating capacity and avoid over-adjustment.

[0145] S333: When the temperature difference is greater than or equal to the third threshold and less than the fourth threshold, reduce the operating frequency of the compressor by a third step.

[0146] The third threshold is smaller than the fourth threshold.

[0147] When the temperature difference is small and positive, the compressor operating power is reduced in smaller steps to fine-tune the system heating capacity and avoid over-adjustment.

[0148] S334: When the temperature difference is greater than or equal to a fourth threshold, reduce the operating power of the compressor by a fourth step.

[0149] The fourth step is longer than the third step.

[0150] When the temperature difference is large and positive, the operating power of the compressor is reduced by a larger step to quickly reduce the system heating capacity and prevent the temperature from being too high.

[0151] S340: After adjusting the operating frequency of the compressor, cyclically determine the temperature difference at intervals of a first preset period, and continue to execute the step of adjusting the operating frequency of the compressor according to the temperature difference.

[0152] After adjusting the operating frequency of the compressor, at intervals of the first preset period (t), the temperature difference is cyclically judged and the compressor frequency is dynamically adjusted. Through periodic monitoring and feedback regulation, it is ensured that the system can operate continuously and stably and respond quickly to environmental changes.

[0153] It should be understood that the specific values of the first threshold, the second threshold, the third threshold, and the fourth threshold can be preset according to specific application situations such as the thermal response characteristics of the target medium, the performance parameters of the compressor, and the heating requirements of the system. This application does not limit this.

[0154] Similarly, the specific values of the first step size, the second step size, the third step size, and the fourth step size can be set according to factors such as the rate of temperature change, the system stability requirements, and the energy efficiency optimization requirements. This application does not limit this either.

[0155] In one example, T2, T1, -T1, -T2 are deviation set values, and Step1 and Step2 are adjustment step sizes, where T2>T1, -T1>-T2, T2 = |-T2|, T1 = |-T1|, and Step1<Step2. △T is judged through a fuzzy interval with the above values, and the compressor frequency increases or decreases by the corresponding step size value: when the △T value is larger, the adjustment step size is larger, and the compressor frequency responds quickly, making the actual outlet temperature quickly approach the target outlet temperature; when the △T value is smaller, the adjustment step size is smaller, and the compressor frequency enters fine adjustment, making the actual outlet temperature approach the target outlet temperature, reducing the overshoot of the compressor frequency and system oscillation; when the △T value satisfies the set dead zone, the compressor frequency is not adjusted, reducing the frequent adjustment of the compressor frequency and prolonging the service life of the compressor.

[0156] The specific implementation steps are as follows:

[0157] When △T≥T2, the compressor frequency decreases by the step size Step2, and after a stable adjustment period t, △T is cyclically judged and adjusted;

[0158] When T1≤△T<T2, the compressor frequency decreases by the step size Step1, and after a stable adjustment period t, △T is cyclically judged and adjusted;

[0159] When -T1≤△T<T1, the dead zone is cyclically judged, and the compressor frequency is not adjusted;

[0160] When -T2≤△T<-T1, the compressor frequency increases by the step size Step1, and after a stable adjustment period t, △T is cyclically judged and adjusted;

[0161] When △T<-T2, the compressor frequency increases by the step size Step2, and after a stable adjustment period t, △T is cyclically judged and adjusted.

[0162] In this embodiment, the outlet temperature of the target medium of the heat pump system is collected in real time, and the difference between the outlet temperature and the target temperature is calculated to accurately adjust the operating frequency of the compressor. In this way, the system operation can be dynamically fine-tuned according to the temperature difference, achieving more efficient and accurate temperature control, improving the stability and response speed of the system, and ensuring that the heat pump always maintains the best performance under different working conditions.

[0163] Secondly, by setting different temperature difference threshold intervals and flexibly adjusting the operating frequency of the compressor according to these intervals, the frequency change of the compressor can be finely controlled through the step-by-step adjustment strategy to avoid over-adjustment and improve the response accuracy and operating stability of the system.

[0164] In addition, this embodiment also regularly judges and monitors the temperature difference by setting a fixed time period to ensure that the operating frequency of the compressor can be continuously adjusted within a suitable period. Through the cyclic adjustment and feedback mechanism, the system can respond to environmental changes more accurately, optimize the temperature control effect, and improve the stability and energy efficiency of the heat pump system.

[0165] The above mainly introduces a method for determining the compressor frequency of a heat pump system according to an embodiment of the present application in conjunction with the accompanying drawings. It should be understood that, although the steps in the flowcharts involved in the embodiments described above are shown in sequence, these steps are not necessarily performed in sequence in the order shown in the figure. Unless otherwise specified in this article, there is no strict order restriction on the execution of these steps, and these steps can be performed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the embodiments described above may include multiple steps or multiple stages, and these steps or stages are not necessarily performed at the same time, but can be performed at different times, and the execution order of these steps or stages is not necessarily performed in sequence, but can be performed in turn or alternately with other steps or at least a part of the steps or stages in other steps. The following is an introduction to a device for determining the compressor frequency of a heat pump system according to an embodiment of the present application in conjunction with the accompanying drawings. For the sake of brevity, appropriate omissions will be made when introducing the device below, and the relevant content can refer to the relevant description in the method above, and will not be repeated.

[0166] Corresponding to the method described in the above embodiment, Figure 4 A structural block diagram of a device 1000 for determining the compressor frequency of a heat pump system provided in an embodiment of the present application is shown. For ease of explanation, only the parts related to the embodiment of the present application are shown.

[0167] like Figure 4 As shown, the device 1000 may include:

[0168] The acquisition module 1001 is used to acquire the on-site ambient temperature of the target medium heated by the heat pump system.

[0169] The calling module 1002 is used to call the target operating condition parameters in the preset database according to the on-site ambient temperature.

[0170] The target operating parameters are the operating parameters corresponding to when the efficiency index of the heat pump system meets the preset requirements at the on-site ambient temperature.

[0171] The operating condition parameters include at least one of the expansion valve opening, CO2 refrigerant flow rate, evaporator inlet temperature, and evaporator outlet temperature.

[0172] The calculation module 1003 is used to input the target operating condition parameters into a preset mathematical model to calculate the work done by the compressor.

[0173] The processing module 1004 is used to determine the operating frequency of the compressor in the heat pump system according to the work done by the compressor.

[0174] Figure 5 A schematic structural diagram of a heat pump control system 5000 provided in an embodiment of the present application is shown.

[0175] like Figure 5 As shown, the heat pump control system may include a heat pump system 2000 and a control device 3000 .

[0176] In one embodiment, the control device 3000 includes Figure 4 The device 1000 for determining the frequency of a compressor of a heat pump system in the embodiment is used to execute the method for determining the frequency of a compressor of a heat pump system proposed in each embodiment of the present application.

[0177] The heat pump system 2000 includes at least a compressor.

[0178] Figure 6 A schematic structural diagram of a heat pump system 2000 provided in an embodiment of the present application is shown.

[0179] like Figure 6 As shown, the heat pump system 2000 may include the following structures:

[0180] 2001, fan; 2002, evaporator; 2003, compressor; 2004, oil-gas separator; 2005, condensing heat exchanger; 2006, filter drier; 2007, electronic expansion valve; 2008, defrost valve; 2009, CO2 flow meter.

[0181] Figure 7 A schematic diagram of the hardware structure of a computer device provided in an embodiment of the present application is shown.

[0182] The computer device may include a processor 7001 and a memory 7002 storing computer program instructions.

[0183] Specifically, the processor 7001 may include a central processing unit (CPU), or an application specific integrated circuit (ASIC), or may be configured to implement one or more integrated circuits of the embodiments of the present application.

[0184] The memory 7002 may include a large capacity memory for data or instructions. By way of example and not limitation, the memory 7002 may include a hard disk drive (HDD), a floppy disk drive, a flash memory, an optical disk, a magneto-optical disk, a magnetic tape, or a universal serial bus (USB) drive or a combination of two or more of these. In one example, the memory 7002 may include a removable or non-removable (or fixed) medium, or the memory 7002 is a non-volatile solid-state memory. The memory 7002 may be inside or outside the integrated gateway disaster recovery device.

[0185] In one example, the memory 7002 may be a read-only memory (ROM). In one example, the ROM may be a mask-programmed ROM, a programmable ROM (PROM), an erasable PROM (EPROM), an electrically erasable PROM (EEPROM), an electrically rewritable ROM (EAROM), or a flash memory, or a combination of two or more of these.

[0186] The memory 7002 may include a read-only memory (ROM), a random access memory (RAM), a magnetic disk storage medium device, an optical storage medium device, a flash memory device, an electrical, optical or other physical / tangible memory storage device. Thus, typically, the memory includes one or more tangible (non-transitory) computer-readable storage media (e.g., a memory device) encoded with software including computer-executable instructions, and when the software is executed (e.g., by one or more processors), it is operable to perform the operations described with reference to the method according to an aspect of the present disclosure.

[0187] The processor 7001 reads and executes the computer program instructions stored in the memory 7002 to implement Figure 2 A method for determining the compressor frequency of a heat pump system in the illustrated embodiment.

[0188] In one example, the computer device may further include a communication interface 7003 and a bus 7004. Figure 7 As shown, the processor 7001, the memory 7002, and the communication interface 7003 are connected via a bus 7004 and communicate with each other.

[0189] The communication interface 7003 is mainly used to implement communication between various modules, devices, units and / or equipment in the embodiments of the present application.

[0190] Bus 7004 includes hardware, software or both, and the components of online data flow billing equipment are coupled to each other. For example, but not limitation, the bus may include Accelerated Graphics Port (AGP) or other graphics bus, Enhanced Industry Standard Architecture (EISA) bus, Front Side Bus (FSB), Hyper Transport (HT) interconnection, Industry Standard Architecture (ISA) bus, InfiniBand interconnection, Low Pin Count (LPC) bus, Memory bus, Micro Channel Architecture (MCA) bus, Peripheral Component Interconnect (PCI) bus, PCI-Express (PCI-X) bus, Serial Advanced Technology Attachment (SATA) bus, Video Electronics Standards Association Local (VLB) bus or other suitable bus or two or more of these combinations. In appropriate cases, bus 7004 may include one or more buses. Although the present application embodiment describes and shows a specific bus, the present application considers any suitable bus or interconnection.

[0191] In addition, in combination with the method for determining the compressor frequency of the heat pump system in the above embodiment, the embodiment of the present application can provide a computer storage medium for implementation. The computer storage medium stores computer program instructions; when the computer program instructions are executed by the processor, any method for determining the compressor frequency of the heat pump system in the above embodiment is implemented.

[0192] An embodiment of the present application also provides a computer program product, including a computer program, which, when executed, implements any one of the methods for determining the compressor frequency of a heat pump system in the above embodiments.

[0193] It should be clear that the present application is not limited to the specific configuration and processing described above and shown in the figures. For the sake of simplicity, a detailed description of the known method is omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of the present application is not limited to the specific steps described and shown, and those skilled in the art can make various changes, modifications and additions, or change the order between the steps after understanding the spirit of the present application.

[0194] The functional blocks shown in the structural block diagram described above can be implemented as hardware, software, firmware or a combination thereof. When implemented in hardware, it can be, for example, an electronic circuit, an application-specific integrated circuit (Application Specific Integrated Circuit, ASIC), appropriate firmware, plug-in, function card, etc. When implemented in software, the elements of the present application are programs or code segments used to perform the required tasks. The program or code segment can be stored in a machine-readable medium, or transmitted on a transmission medium or communication link by a data signal carried in a carrier. "Machine-readable medium" can include any medium capable of storing or transmitting information. Examples of machine-readable media include electronic circuits, semiconductor memory devices, read-only memory (Read-Only Memory, ROM), flash memory, erasable read-only memory (Erasable ReadOnly Memory, EROM), floppy disks, compact disc read-only memory (Compact Disc Read-Only Memory, CD-ROM), optical discs, hard disks, optical fiber media, radio frequency (Radio Frequency, RF) links, etc. The code segment can be downloaded via a computer network such as the Internet, an intranet, etc.

[0195] Aspects of the present disclosure are described above with reference to the flowchart and / or block diagram of the method, device (system) and computer program product according to the embodiment of the present disclosure. It should be understood that each box in the flowchart and / or block diagram and the combination of each box in the flowchart and / or block diagram can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device to produce a machine so that these instructions executed by the processor of the computer or other programmable data processing device enable the implementation of the function / action specified in one or more boxes of the flowchart and / or block diagram. Such a processor can be, but is not limited to, a general-purpose processor, a special-purpose processor, a special application processor, or a field programmable logic circuit. It can also be understood that each box in the block diagram and / or flowchart and the combination of boxes in the block diagram and / or flowchart can also be implemented by dedicated hardware that performs a specified function or action, or can be implemented by a combination of dedicated hardware and computer instructions.

[0196] The above is only a specific implementation of the present application. Those skilled in the art can clearly understand that for the convenience and simplicity of description, the specific working processes of the systems, modules and units described above can refer to the corresponding processes in the aforementioned method embodiments, and will not be repeated here. It should be understood that the protection scope of the present application is not limited to this. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in this application, and these modifications or replacements should be included in the protection scope of this application.

Claims

1. A method for determining the compressor frequency of a heat pump system, characterized in that: include: Obtaining the on-site ambient temperature of the target medium heated by the heat pump system; Calling a target operating condition parameter in a preset database according to the on-site ambient temperature, the target operating condition parameter being an operating condition parameter corresponding to when the efficiency index of the heat pump system at the on-site ambient temperature reaches a preset requirement, the operating condition parameter including at least one of an expansion valve opening, a CO2 refrigerant flow rate, an evaporator inlet temperature, and an evaporator outlet temperature; Inputting the target operating condition parameters into a preset mathematical model to calculate the work done by the compressor; The operating frequency of the compressor in the heat pump system is determined according to the work done by the compressor.

2. The method according to claim 1, characterized in that After determining the operating frequency of the compressor in the heat pump system according to the work done by the compressor, the method further includes: collecting the outlet temperature of the target medium in the heat pump system; calculating a temperature difference between the outlet temperature and a target outlet temperature; The operating frequency of the compressor is adjusted according to the temperature difference.

3. The method according to claim 2, characterized in that The step of adjusting the operating frequency of the compressor according to the temperature difference comprises: When the temperature difference is less than a first threshold, increasing the operating frequency of the compressor by a first step; When the temperature difference is greater than or equal to the first threshold value and less than a second threshold value, increasing the operating frequency of the compressor by a second step length, wherein the second step length is smaller than the first step length; When the temperature difference is greater than or equal to a third threshold value and less than a fourth threshold value, reducing the operating frequency of the compressor by a third step length; When the temperature difference is greater than or equal to the fourth threshold, the operating frequency of the compressor is reduced by a fourth step length, and the fourth step length is greater than the third step length.

4. The method according to claim 2, characterized in that: The method further comprises: After adjusting the operating frequency of the compressor, the temperature difference is cyclically determined at intervals of a first preset period, and the step of adjusting the operating frequency of the compressor according to the temperature difference is continued.

5. The method according to any one of claims 1 to 4, characterized in that The preset mathematical model includes a first model and a second model, and the target operating condition parameters are input into the preset mathematical model to calculate the work done by the compressor, including: Obtaining the flow value, inlet temperature and outlet temperature of the target medium in the heat pump system; Using the first model, based on the flow value, the inlet temperature and the outlet temperature, the required heating amount of the target medium is calculated; Using the second model, according to the target operating condition parameters, the heat absorbed by the evaporator is calculated; The work done by the compressor is determined according to the required heating amount of the target medium and the heat absorbed by the evaporator.

6. The method according to any one of claims 1 to 4, characterized in that The preset database includes a mapping relationship between ambient temperature, efficiency index of the heat pump system and operating parameters.

7. The method according to any one of claims 1 to 4, characterized in that The calling of target operating condition parameters in a preset database according to the on-site ambient temperature includes: In the case that the preset database does not contain the on-site ambient temperature, the target operating condition parameter is calculated using an interpolation method according to the operating condition parameters corresponding to the ambient temperature adjacent to the on-site ambient temperature in the preset database.

8. A heat pump control system, characterized in that: Includes heat pump system and control equipment; The heat pump system comprises at least a compressor; and the control device is used to execute the method according to any one of claims 1 to 7.

9. A computer device, characterized in that: The device comprises: a processor and a memory storing computer program instructions; the processor reads and executes the computer program instructions to implement the method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer program instructions, and when the computer program instructions are executed by a processor, the method according to any one of claims 1 to 7 is implemented.

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