A heat pump unit parallel operation regulation method, device, equipment and storage medium

Abstract

Embodiments of the present application disclose a heat pump unit parallel operation regulation method, device, equipment and storage medium, receiving a start-up instruction, in response to the start-up instruction, executing a start-up strategy; after running for a first preset time, periodically detecting the average return water temperature of the parallel unit, and determining a first temperature difference according to the difference between the average return water temperature and a preset target temperature; determining a temperature difference change rate according to the difference between the first temperature difference and a second temperature difference, the second temperature difference being the first temperature difference determined in the previous period; determining a start-up quantity regulation strategy and a frequency regulation strategy according to the first temperature difference, the temperature difference change rate and a preset reference relationship; controlling the start and stop of the compressor of the corresponding heat pump unit according to the start-up quantity regulation strategy, and adjusting the frequency of the currently started compressor according to the frequency regulation strategy; the technical problem of high energy consumption of the existing parallel operation heat pump unit can be solved, and the overall energy consumption of the parallel operation heat pump unit is reduced.

Description

Technical Field

[0001] This application relates to the field of heat pump control technology, and in particular to a method, apparatus, equipment and storage medium for parallel operation control of heat pump units. Background Technology

[0002] Heat pump units are widely used in people's work and daily life due to their advantages such as high efficiency and environmental friendliness. As the application scenarios of heat pump units become more widespread, the control requirements for their compressors are also increasing. Traditional fixed-frequency compressors, with their fixed operating speed, are difficult to adapt to changing usage needs. Therefore, variable-frequency technology has been introduced, and the use of variable-frequency compressors in heat pump units has become a trend.

[0003] With the widespread application of variable frequency heat pump units in various scenarios such as refrigeration, hot water, heating, and drying, it is common to see multiple heat pump units operating in parallel. The existing control strategy for parallel operation of heat pump units typically involves turning on all heat pump units and uniformly controlling the operating frequency of all compressors, meaning all compressors operate at the same frequency. However, in actual operation, parallel-operated heat pump units may frequently operate under partial load. If all compressors operate at the same frequency, under partial load conditions, some compressors may be overloaded or inefficient, while others may be idle or operating inefficiently, leading to unnecessary energy waste. Summary of the Invention

[0004] This application provides a method, apparatus, equipment, and storage medium for controlling parallel operation of heat pump units, which can solve the technical problem of high energy consumption in existing parallel operation heat pump units and reduce the overall energy consumption of parallel operation heat pump units.

[0005] In a first aspect, embodiments of this application provide a method for controlling the parallel operation of heat pump units, used for parallel operation of multiple heat pump units connected in parallel. The method includes:

[0006] Receive the power-on command, respond to the power-on command, and execute the power-on policy;

[0007] After running for the first preset time, the average return water temperature of the parallel units is periodically detected, and the first temperature difference is determined based on the difference between the average return water temperature and the preset target temperature.

[0008] The rate of change of temperature difference is determined based on the difference between the first temperature difference and the second temperature difference, where the second temperature difference is the first temperature difference determined in the previous cycle.

[0009] Based on the first temperature difference, the rate of change of temperature difference, and the preset comparison relationship, the start-up quantity control strategy and the frequency control strategy are determined. The start-up quantity control strategy includes full-on control strategy, constant temperature start-up control strategy, adding control strategy, reducing control strategy and maintenance strategy. The frequency control strategy includes full PID frequency modulation strategy, fixed single-unit PID frequency modulation strategy, fixed single-unit fixed frequency control strategy, maintenance frequency strategy and shutdown strategy.

[0010] The start-up and shutdown of the compressors of the corresponding heat pump units are controlled according to the start-up quantity control strategy, and the frequency of the currently running compressors is adjusted according to the frequency control strategy.

[0011] In one embodiment, receiving a power-on command and, in response to the power-on command, executing a power-on policy includes:

[0012] Receives the start-up command, responds to the start-up command, and detects the average return water temperature of the parallel units;

[0013] The first temperature difference is determined based on the difference between the average return water temperature and the preset target temperature;

[0014] In cooling mode and when the first temperature difference is greater than the first preset threshold, or in heating mode and when the first temperature difference is less than the second preset threshold, the compressors of a first number of heat pump units are controlled to start, and the first number is the total number of parallel units minus one.

[0015] The compressor frequency is adjusted according to the preset PID frequency regulation strategy of each currently activated heat pump unit.

[0016] In one embodiment, based on the first temperature difference, the rate of change of temperature difference, and a preset control relationship, a start-up quantity control strategy and a frequency control strategy are determined, including:

[0017] The first dimension parameter is determined based on the first temperature difference and the preset comparison relationship;

[0018] The second dimension parameter is determined based on the temperature difference change rate and the preset comparison relationship;

[0019] Based on the intersection of the first-dimensional parameters and the second-dimensional parameters, determine the power-on quantity control strategy and the frequency control strategy.

[0020] In one embodiment, determining a first dimension parameter based on a first temperature difference and a preset control relationship includes:

[0021] A preset temperature difference range is defined, and the temperature difference range has a first preset correlation with the first dimension parameter.

[0022] By comparing the first temperature difference with the temperature difference range, the target temperature difference range corresponding to the first temperature difference is determined;

[0023] The first dimension parameter corresponding to the target temperature difference range is determined based on the first preset comparison relationship;

[0024] Based on the temperature difference change rate and the preset control relationship, the second dimension parameters are determined, including:

[0025] A preset temperature difference change rate range is defined, and a second preset correlation exists between the temperature difference change rate range and the second dimension parameter.

[0026] By comparing the rate of change of temperature difference with the range of the rate of change of temperature difference, the target range of the rate of change of temperature difference is determined.

[0027] The second dimension parameter corresponding to the target temperature difference change rate range is determined based on the second preset comparison relationship.

[0028] In one embodiment, the power-on quantity control strategy and frequency control strategy are determined based on the intersection of the first dimension parameter and the second dimension parameter, including:

[0029] When the first dimension parameter is within the range of the first parameter, the power-on quantity control strategy is determined to be the full-on control strategy, and the frequency control strategy is determined to be the full PID frequency modulation strategy.

[0030] When the first dimension parameter is within the range of the second parameter, and the second dimension parameter is within the range of the third parameter, the start-up quantity control strategy is determined to be the addition control strategy, and the frequency control strategy is determined to be the full PID frequency modulation strategy.

[0031] When the first dimension parameter is within the range of the fourth parameter and the second dimension parameter is within the range of the fifth parameter, the start-up control strategy is determined to be the addition control strategy and the frequency control strategy is determined to be the fixed single-unit PID frequency modulation strategy.

[0032] When the first dimension parameter is within the range of the sixth parameter and the second dimension parameter is within the range of the seventh parameter, the power-on quantity control strategy is determined to be a maintenance strategy, and the frequency control strategy is determined to be a fixed single-unit fixed frequency control strategy.

[0033] When the first dimension parameter is within the range of the eighth parameter and the second dimension parameter is within the range of the ninth parameter, the start-up quantity control strategy is determined to be the reduce-up control strategy, and the frequency control strategy is determined to be the full PID frequency modulation strategy.

[0034] When the first dimension parameter is within the range of the tenth parameter, the frequency control strategy is determined to be a shutdown strategy, which is used to control all compressors to shut down.

[0035] In one embodiment, after determining that the number of machines to be controlled is an increase control strategy and the frequency control strategy is a full PID frequency modulation strategy when the first dimension parameter is within the range of the second parameter and the second dimension parameter is within the range of the third parameter, the process includes:

[0036] Detect the current operating frequency of the compressor in the currently running heat pump unit;

[0037] The start-up and shutdown of the compressors of the corresponding heat pump units are controlled according to the start-up quantity control strategy, including:

[0038] According to the addition control strategy, when the current operating frequency meets the preset first condition, the compressor of a heat pump unit is added and started. The preset first condition is that the current operating frequency of all currently started heat pump units reaches the preset maximum frequency, the limited frequency, or the limited high frequency, and continues for a first preset time.

[0039] The newly started compressor is controlled to adjust its frequency according to its own preset PID frequency regulation strategy, and the operating frequency of other currently started compressors is controlled to be reduced to a preset fixed frequency.

[0040] In one embodiment, after determining that the number of machines to be turned on is a reduction control strategy and the frequency control strategy is a full PID frequency modulation strategy when the first dimension parameter is in the range of the eighth parameter and the second dimension parameter is in the range of the ninth parameter, the process includes:

[0041] Detect the current operating frequency of the compressor in the currently running heat pump unit;

[0042] The start-up and shutdown of the compressors of the corresponding heat pump units are controlled according to the start-up quantity control strategy, including:

[0043] According to the reduction control strategy, when the current operating frequency meets the preset second condition, the compressor of one heat pump unit is shut down. The preset second condition is that the current operating frequency of all currently running heat pump units reaches the preset minimum frequency or below the restricted low frequency.

[0044] In a second aspect, embodiments of this application provide a parallel operation control device for heat pump units, used for parallel operation of multiple heat pump units connected in parallel. The parallel operation control device includes:

[0045] The power-on module is used to receive power-on commands and, in response to the power-on commands, execute power-on strategies.

[0046] The temperature difference determination module is used to periodically detect the average return water temperature of the parallel units after running for a preset time, and determine the first temperature difference based on the difference between the average return water temperature and the preset target temperature.

[0047] The rate of change determination module is used to determine the rate of change of temperature difference based on the difference between the first temperature difference and the second temperature difference, wherein the second temperature difference is the first temperature difference determined in the previous cycle.

[0048] The strategy determination module is used to determine the start-up quantity control strategy and frequency control strategy based on the first temperature difference, the temperature difference change rate, and the preset comparison relationship. The start-up quantity control strategy includes full-on control strategy, constant temperature start-up control strategy, adding control strategy, reducing control strategy and maintenance strategy. The frequency control strategy includes full PID frequency modulation strategy, fixed single-unit PID frequency modulation strategy, fixed single-unit fixed frequency control strategy, maintenance frequency strategy and shutdown strategy.

[0049] The control module is used to control the start and stop of the compressor of the corresponding heat pump unit according to the start-up quantity control strategy, and to adjust the frequency of the currently running compressor according to the frequency control strategy.

[0050] In a third aspect, embodiments of this application provide a parallel operation control device for heat pump units, comprising:

[0051] Memory and one or more processors;

[0052] Memory, used to store one or more programs;

[0053] When one or more programs are executed by one or more processors, the one or more processors implement the parallel operation control method of heat pump units as described in the first aspect.

[0054] In a fourth aspect, embodiments of this application provide a storage medium for storing computer-executable instructions, which, when executed by a computer processor, are used to perform the parallel operation control method for heat pump units as described in the first aspect.

[0055] In the parallel operation control of heat pump units in this embodiment, after the first preset time of start-up operation, the average return water temperature of the heat pump units is periodically detected. A first temperature difference is determined based on the difference between the average return water temperature and the preset target temperature. The temperature difference change rate is determined based on the difference between the first temperature difference and the second temperature difference, wherein the second temperature difference is the first temperature difference determined in the previous cycle. The start-up quantity control strategy and the frequency control strategy are determined based on the first temperature difference, the temperature difference change rate, and the preset comparison relationship. The start-up quantity control strategy controls the start-up and shutdown of the compressor of the corresponding heat pump unit. The frequency control strategy adjusts the frequency of the currently started compressor. By employing the aforementioned technical means, the start-up quantity control strategy and frequency control strategy can be jointly determined through two dimensions: the first temperature difference and the rate of change of temperature difference. Based on the start-up quantity control, the number of heat pump units in operation is adapted to the current load. Compared with the existing parallel operation mode where all heat pump units are in a state of operation, this embodiment, based on the start-up quantity control strategy, can shut down some inefficient heat pump units and add heat pump units when the system is overloaded, so that the number of heat pump units in operation meets the current load demand, thereby reducing the overall energy consumption of the parallel-operated heat pump units. In addition, the frequency of the currently operating compressor is adjusted according to the frequency control strategy. This embodiment uses periodic detection to obtain the first temperature difference and the rate of change of temperature difference for compressor frequency control. In the face of complex actual operating environments, the frequency control strategy can be determined based on the first temperature difference and the rate of change of temperature difference corresponding to the actual operating effect, thereby improving the accuracy of compressor frequency control of the heat pump units. Based on the improved accuracy of compressor frequency control, the load adaptability is improved and frequent start-stop situations are reduced, further reducing the overall energy consumption of the parallel-operated heat pump units. Attached Figure Description

[0056] Figure 1 This is a flowchart of a parallel operation control method for heat pump units provided in an embodiment of this application;

[0057] Figure 2 This is a schematic diagram of the structure of a heat pump unit parallel operation control device provided in an embodiment of this application;

[0058] Figure 3 This is a schematic diagram of the structure of a heat pump unit parallel operation control device provided in an embodiment of this application. Detailed Implementation

[0059] To make the objectives, technical solutions, and advantages of this application clearer, specific embodiments of this application will be described in further detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely for explaining this application and not for limiting it. It should also be noted that, for ease of description, only the parts relevant to this application are shown in the drawings, not all of them. Before discussing exemplary embodiments in more detail, it should be mentioned that some exemplary embodiments are described as processes or methods depicted as flowcharts. Although the flowcharts describe operations (or steps) as sequential processes, many of these operations can be performed in parallel, concurrently, or simultaneously. Furthermore, the order of the operations can be rearranged. A process can be terminated when its operation is completed, but it may also have additional steps not included in the drawings. A process can correspond to a method, function, procedure, subroutine, subroutine, etc.

[0060] With the widespread application of variable frequency heat pump units in various scenarios such as refrigeration, hot water, heating, and drying, it is common to see multiple heat pump units operating in parallel. The existing control strategy for parallel operation of heat pump units typically involves turning on all heat pump units and uniformly controlling the operating frequency of all compressors, meaning all compressors operate at the same frequency. However, in actual operation, parallel-operated heat pump units may frequently operate under partial load. If all compressors operate at the same frequency, under partial load conditions, some compressors may be overloaded or inefficient, while others may be idle or operating inefficiently, leading to unnecessary energy waste.

[0061] Based on this, the present application provides a method, apparatus, equipment, and storage medium for parallel operation control of heat pump units. The aim is to, during parallel operation control of heat pump units, after a first preset time of operation, periodically detect the average return water temperature of the heat pump units, determine a first temperature difference based on the difference between the average return water temperature and a preset target temperature, determine the temperature difference change rate based on the difference between the first temperature difference and a second temperature difference, wherein the second temperature difference is the first temperature difference determined in the previous cycle, determine a start-up quantity control strategy and a frequency control strategy based on the first temperature difference, the temperature difference change rate, and a preset correlation, control the start-up quantity control strategy to turn on and off the compressors of the corresponding heat pump units, and adjust the frequency of the currently running compressors according to the frequency control strategy. By employing the aforementioned technical means, the start-up quantity control strategy and frequency control strategy can be jointly determined through two dimensions: the first temperature difference and the rate of change of temperature difference. Based on the start-up quantity control, the number of heat pump units in operation is adapted to the current load. Compared with the existing parallel operation mode where all heat pump units are in a state of operation, this embodiment, based on the start-up quantity control strategy, can shut down some inefficient heat pump units and add heat pump units when the system is overloaded, so that the number of heat pump units in operation meets the current load demand, thereby reducing the overall energy consumption of the parallel-operated heat pump units. In addition, the frequency of the currently operating compressor is adjusted according to the frequency control strategy. This embodiment uses periodic detection to obtain the first temperature difference and the rate of change of temperature difference for compressor frequency control. In the face of complex actual operating environments, the frequency control strategy can be determined based on the first temperature difference and the rate of change of temperature difference corresponding to the actual operating effect, thereby improving the accuracy of compressor frequency control of the heat pump units. Based on the improved accuracy of compressor frequency control, the load adaptability is improved and frequent start-stop situations are reduced, further reducing the overall energy consumption of the parallel-operated heat pump units.

[0062] Figure 1 A flowchart of a parallel operation control method for heat pump units provided in this application embodiment is given. The parallel operation control method for heat pump units provided in this embodiment can be executed by a parallel operation control device for heat pump units. This device can be implemented through software and / or hardware. The device can consist of two or more physical entities, or it can consist of a single physical entity. Generally, the parallel operation control device for heat pump units can be electronic equipment corresponding to the heat pump unit, such as air conditioners and underfloor heating systems.

[0063] The following description uses an air conditioner as the main entity implementing the parallel operation control method for heat pump units. (Refer to...) Figure 1 This parallel operation control method for heat pump units is used for heat pump units connected in parallel. The parallel operation control method for heat pump units specifically includes:

[0064] S101: Receive the power-on command and, in response to the power-on command, execute the power-on policy.

[0065] Upon initial power-on of the parallel units, the units receive a start-up command and, in response, execute a start-up strategy. This strategy includes: acquiring the current operating parameters of the heat pump unit; determining the current operating mode based on these parameters (either heating or cooling); receiving a temperature setting signal; and determining a preset target temperature value. This temperature setting signal can be input by the user via remote control or automatically triggered by the controller. For example, if the temperature before the heat pump unit was shut down was 26°C, then upon restarting, the controller automatically triggers the temperature setting signal to determine the preset target temperature as 26°C.

[0066] In one embodiment, the preset target temperature value is either the heating target temperature value in heating mode or the cooling target temperature value in cooling mode. In heating mode, a temperature setting signal is received, and the heating target temperature value is determined based on the temperature setting signal. In cooling mode, a temperature setting signal is received, and the cooling target temperature value is determined based on the temperature setting signal.

[0067] After the heat pump unit is powered on, to protect the unit and improve energy efficiency, the compressor will only start after the return water temperature reaches a certain value. Therefore, the start-up strategy also includes: detecting the average return water temperature of the parallel units. This can be done by detecting the return water temperature of each heat pump unit in the parallel units. Since the return water temperature of each heat pump unit may differ, the average return water temperature is obtained by averaging the return water temperatures of all heat pump units. The average return water temperature of all heat pump units is used to determine whether the compressor of the heat pump unit needs to be turned on. The first temperature difference is determined based on the difference between the average return water temperature and the preset target temperature. In cooling mode and the first temperature difference is greater than a first preset threshold, or in heating mode and the first temperature difference is less than a second preset threshold, the compressors of a first number of heat pump units are controlled to start. The first number is the total number of parallel units minus one. For example, assuming there are N heat pump units in the parallel units, in cooling mode and the first temperature difference is greater than the first preset threshold, the compressors of N-1 heat pump units are controlled to start.

[0068] For example, assuming there are N heat pump units in parallel operation, in cooling mode, the first preset threshold is a preset cooling start-up hysteresis value. When T01-R01>R03, the compressors of N-1 heat pump units are controlled to start, where T01 is the average return water temperature, R01 is the preset target temperature in cooling mode, i.e., the cooling target temperature value, and R03 is the preset cooling start-up hysteresis value.

[0069] For example, assuming there are N heat pump units in parallel operation, in heating mode, the second preset threshold is a preset heating start-up hysteresis value. When T01-R02 < R05, the compressors of N-1 heat pump units are controlled to start, where T01 is the average return water temperature, R02 is the preset target temperature in heating mode, i.e., the heating target temperature value, and R05 is the preset heating start-up hysteresis value.

[0070] It should be noted that in cooling mode, if the first temperature difference is less than or equal to the first preset threshold, the conditions for starting the heat pump unit's compressor are not met, and the compressor will not be started or its frequency adjusted. In heating mode, if the first temperature difference is greater than or equal to the second preset threshold, the conditions for starting the heat pump unit's compressor are not met, and the compressor will not be started or its frequency adjusted.

[0071] In cooling mode and when the first temperature difference is greater than a first preset threshold, or in heating mode and when the first temperature difference is less than a second preset threshold, after controlling the compressors of a first number of heat pump units to start, the corresponding compressors are controlled to run at a preset platform frequency for a preset time. By controlling the compressors to run at the platform frequency for a period of time after startup, temperature fluctuations during the startup phase are reduced, thereby improving user comfort. Furthermore, this helps improve the stability of the internal pressure of the heat pump unit, thus enhancing the overall reliability of the heat pump unit's operation.

[0072] After the compressor has been running at a preset platform frequency for a preset time, the compressor frequency is regulated according to the preset PID frequency regulation strategy of each currently activated heat pump unit. Each heat pump unit has its own preset PID control strategy. Therefore, during the execution of the start-up strategy, if the compressor of a heat pump unit starts, the compressor frequency can be regulated according to its own preset PID control strategy.

[0073] As described above, by controlling the compressors of heat pump units with a total number of parallel units minus one to start when the first temperature difference is greater than the first preset threshold in cooling mode, or when the first temperature difference is less than the second preset threshold in heating mode, and reserving one heat pump unit to be in a closed state, it is possible to avoid the units from running at full load immediately after startup, which would cause frequent start-ups and shutdowns, thereby improving the reliability and stability of the operation of the parallel units.

[0074] S102. After running for the first preset time, periodically detect the average return water temperature of the parallel units, and determine the first temperature difference based on the difference between the average return water temperature and the preset target temperature.

[0075] According to the preset PID frequency regulation strategy of each currently activated heat pump unit, the compressor frequency is regulated. After the compressor runs for a first preset time, the average return water temperature of the heat pump unit is periodically detected. The first temperature difference is determined based on the difference between the average return water temperature and the preset target temperature. For example, assuming the cycle is 10 minutes and the preset target temperature is 26℃, the average return water temperature is detected every 10 minutes. Assuming the average return water temperature detected this time is 30℃, the first temperature difference for this cycle is determined to be 4℃ based on the difference between the average return water temperature of 30℃ and the preset target temperature of 26℃.

[0076] For example, the first preset time can be set to be the same as the cycle time. For instance, if the cycle time is 10 minutes, the first preset time can be set to 10 minutes.

[0077] As described above, by periodically detecting the average return water temperature and obtaining the first temperature difference for this cycle based on the difference between the average return water temperature and the preset target temperature, it is possible to determine whether to add or remove compressors or not to make any adjustments based on the changes in the first temperature difference corresponding to multiple cycles, or to determine the frequency control strategy for the compressors of each started heat pump unit. Compared with the existing parallel unit where all compressors operate at the same frequency, this embodiment adjusts the start-up quantity control strategy and frequency control strategy based on the first temperature difference corresponding to the actual operating results. This can improve the adaptability of the parallel unit to the actual load required by the environment, thereby reducing the overall energy consumption of the parallel unit.

[0078] S103. Determine the rate of change of temperature difference based on the difference between the first temperature difference and the second temperature difference, wherein the second temperature difference is the first temperature difference determined in the previous cycle.

[0079] The average return water temperature of the parallel units is periodically monitored, and the first temperature difference for this cycle is determined based on the difference between the average return water temperature and the preset target temperature. The first temperature difference determined in the previous cycle is recorded as the second temperature difference. The rate of change of temperature difference can be determined based on the difference between the first and second temperature differences. For example, the rate of change of temperature difference is obtained by the ratio of the difference between the first and second temperature differences to the cycle (duration). For instance, if the first temperature difference (i.e., the second temperature difference) determined in the previous cycle is 8℃, and the first temperature difference determined in this cycle is 4℃, the difference is 4℃, and the cycle (duration) is 20 minutes, then the rate of change of temperature difference is 0.2℃ / min.

[0080] As described above, by periodically detecting the average return water temperature, the first temperature difference for the corresponding period and the rate of change of temperature difference between two adjacent periods are obtained. Subsequently, the number of units to be started and the frequency control strategy can be determined based on the two dimensions of the first temperature difference and the rate of change of temperature difference. This achieves multi-dimensional consideration, thereby improving the accuracy of temperature control and the adaptability of the number of units started in parallel to actual needs, and thus reducing the overall energy consumption of the parallel units.

[0081] S104. Based on the first temperature difference, the rate of change of temperature difference, and the preset comparison relationship, determine the start-up quantity control strategy and the frequency control strategy. The start-up quantity control strategy includes the full-on control strategy, the constant temperature start-up control strategy, the add-machine control strategy, the reduce-machine control strategy, and the maintenance strategy. The frequency control strategy includes the full PID frequency modulation strategy, the fixed single-unit PID frequency modulation strategy, the fixed single-unit fixed frequency control strategy, the maintenance frequency strategy, and the shutdown strategy.

[0082] The system includes preset operating quantity control strategies and frequency control strategies. The operating quantity control strategies include a full-on control strategy, a constant-temperature operating control strategy, an add-on control strategy, a reduce-on control strategy, and a maintenance strategy. The full-on control strategy activates the compressors of all heat pump units. For example, in a parallel system with 10 heat pump units, the full-on control strategy activates the compressors of all 10 units. The constant-temperature operating control strategy activates the compressors by one less than the number operating units before the constant-temperature shutdown. For example, if 5 heat pump units were operating before the constant-temperature shutdown, the constant-temperature operating control strategy activates the compressors of 4 units. The add-on control strategy includes directly activating one additional unit (i.e., adding one more unit); or, if the current operating frequency meets a preset first condition, activating the compressor of one additional heat pump unit. The preset first condition is that the current operating frequency of all currently activated heat pump units reaches a preset maximum frequency (K01), a limited frequency (K02), or a limited high-frequency frequency (K03), and remains at this frequency for a preset duration. For example, the first preset condition is that the current operating frequency of all currently activated heat pump units reaches a preset maximum frequency (K01); or, the first preset condition is that the current operating frequency of all currently activated heat pump units reaches a preset limit frequency (K02); or, the first preset condition is that the current operating frequency of all currently activated heat pump units reaches a preset limit high frequency (K03); or the first preset condition is that the current operating frequency of some currently activated heat pump units reaches a preset maximum frequency (K01), the current operating frequency of some heat pump units reaches a preset limit frequency (K02), and the current operating frequency of some heat pump units reaches a preset limit high frequency (K03). It should be noted that when adding a compressor to a heat pump unit, priority is given to adding heat pump units with short operating times and no faults. It should also be noted that after the number of activated units changes, the preset first condition is recalculated according to the new cycle. It should be noted that when a new compressor of a heat pump unit is started, the frequency of the compressors of all previously started heat pump units is reduced by a preset frequency (e.g., the preset KO1 frequency); if the frequency of the compressors of all previously started heat pump units is at the minimum frequency, the current frequency is maintained. The compressor reduction control strategy includes: directly shutting down the compressor of one heat pump unit (i.e., reducing one unit); or, shutting down the compressor of one heat pump unit when the current operating frequency meets a preset second condition. The preset second condition is that the current operating frequency of all currently started heat pump units reaches a preset minimum frequency or falls below a restricted low-frequency frequency. It should be noted that when shutting down the compressor of a heat pump unit, priority is given to shutting down heat pump units that have been running for a longer period. It should be noted that in non-emergency stop situations, when only one heat pump unit has its compressor running, the compressor reduction control strategy is not executed. The maintenance strategy maintains the number of currently operating heat pump units, i.e., neither increasing nor decreasing.It should be noted that when implementing the maintenance strategy, if the currently operating heat pump unit fails and shuts down, the corresponding number of heat pump unit compressors need to be started to maintain the current number of operating units.

[0083] Frequency control strategies include full PID frequency regulation, fixed single-unit PID frequency regulation, fixed single-unit fixed frequency control, frequency maintenance, and shutdown strategies. The full PID regulation strategy regulates the compressor frequency according to the preset PID frequency regulation strategy of each currently running heat pump unit. The fixed single-unit PID control strategy selects one heat pump unit to adjust its compressor frequency according to its own preset PID control strategy, while the compressor frequencies of other currently running heat pump units remain unchanged. Specifically, when selecting a fixed single heat pump unit according to its preset PID control strategy, during frequency increase, priority is given to the heat pump unit with the smallest frequency increase among the currently running heat pump units; during frequency decrease, priority is given to the heat pump unit with the highest frequency decrease among the currently running heat pump units. The fixed single-unit fixed frequency control strategy selects one heat pump unit to adjust its compressor frequency according to a preset fixed frequency, while the compressor frequencies of other currently running heat pump units remain unchanged. The preset fixed frequencies include Fixed Frequency Adjustment 1 (K06), Fixed Frequency Adjustment 2 (K07), Fixed Frequency Adjustment 3 (K08), Fixed Frequency Adjustment 4 (K09), and Fixed Frequency Adjustment 5 (K10). The frequency maintenance strategy is to maintain the current frequency without adjustment. The shutdown strategy is to shut down all compressors of the heat pump units.

[0084] It should be noted that when the preset conditions are met and the full-on control strategy, constant temperature start-up control strategy, or emergency stop are triggered, they will be executed immediately without waiting for the frequency adjustment cycle.

[0085] In one embodiment, a preset temperature difference range is established, and this temperature difference range has a first preset correlation relationship with the first dimension parameters (i.e., the parameters of the number of units operated and the frequency control strategy). For example, a larger temperature difference corresponds to a larger number of units operated. A larger temperature difference requires higher capacity, and therefore more heat pump units need to be operated. For example, in cooling mode, under the same temperature difference change rate, the temperature difference range [R03, R03+4] (in °C) corresponds to a constant temperature operation control strategy and a full PID control strategy for the number of units operated. The temperature difference range [R03+4, +∞] (in °C) corresponds to a full-on control strategy and a full PID control strategy for the frequency control strategy. A preset temperature difference change rate range is also established, and this temperature difference change rate range has a second preset correlation relationship with the second dimension parameters (i.e., the parameters of the number of units operated and the frequency control strategy). For example, under the same temperature difference value, the operating quantity control strategy for the temperature difference change rate range [-0.25, 0] (unit: ℃ / min) is an added-unit control strategy, and the corresponding frequency control strategy is a full PID control strategy. The operating quantity control strategy for the temperature difference change rate range [-0.5, -0.25] (unit: ℃ / min) is a maintenance strategy, and the corresponding frequency control strategy is a fixed single-unit PID control strategy. Integrating the first and second preset comparison relationships, a complete two-dimensional preset comparison relationship can be obtained. As described above, through the first preset comparison relationship, when the temperature difference is large, the number of operating units is increased or the frequency is adjusted based on the PID control strategy, allowing more compressors to participate in the work to quickly reduce the temperature difference, thereby shortening the time to reach the preset target temperature and improving the user experience. By using the second preset control relationship, when the rate of temperature difference change decreases rapidly, the number of units turned on can be increased or the frequency can be adjusted based on the full PID control strategy to improve the rate of temperature difference change and accelerate the reduction of the temperature difference. When the rate of temperature difference change increases rapidly, the number of units turned on can be maintained or reduced or the frequency can be reduced at a fixed frequency. This means that the rate of temperature difference change at this time meets the requirement of reaching the preset target temperature within the preset target temperature time. The number of units turned on or the frequency can be reduced appropriately to achieve energy saving without affecting the achievement of the preset target temperature within the preset target temperature time, thereby further improving the user experience.

[0086] In one embodiment, a reference table with preset comparison relationships is provided for the cooling mode, as shown in Tables 1 and 2 below. The full-on control strategy is represented by 11; the constant-temperature start-up control strategy is represented by 12; the strategy of adding a new heat pump unit is represented by 131; the strategy of adding a heat pump unit's compressor when the current operating frequency of all currently running heat pump units reaches a preset maximum frequency (K01) or a limited frequency (K02) is represented by 132; the strategy of adding a heat pump unit's compressor when the current operating frequency of all currently running heat pump units reaches a preset maximum frequency (K01) or a limited high-frequency frequency (K03) is represented by 133; the strategy of reducing the compressor of a heat pump unit is represented by 141; the strategy of reducing the compressor of a heat pump unit is represented by 142 when the current operating frequency meets a preset second condition; and the maintenance strategy is represented by 15. The full PID frequency modulation strategy is represented by 21, the fixed single-unit PID frequency modulation strategy is represented by 22; the fixed single-unit fixed frequency control strategy executing fixed frequency 1 is represented by 231, the fixed single-unit fixed frequency control strategy executing fixed frequency 2 is represented by 232, the fixed single-unit fixed frequency control strategy executing fixed frequency 3 is represented by 233, the fixed single-unit fixed frequency control strategy executing fixed frequency 4 is represented by 234, the fixed single-unit fixed frequency control strategy executing fixed frequency 5 is represented by 235; the frequency maintenance strategy is represented by 24; and the shutdown strategy is represented by 25.

[0087] Table 1:

[0088]

[0089]

[0090] Table 2:

[0091]

[0092] In Tables 1 and 2, △T (°C) represents the temperature difference range, and Φ (°C / min) represents the temperature difference change rate range. R03 represents the hysteresis value of cooling start-up, and R04 represents the hysteresis value of cooling shutdown. Based on the preset correspondence in Tables 1 and 2, when the corresponding first temperature difference is obtained through periodic detection, the first temperature difference can be compared with the temperature difference range to determine the target temperature difference range corresponding to the first temperature difference. For example, if the first temperature difference is 4°C, when R03 = 3, the corresponding target temperature difference range is [R03, R03 + 4) (unit: °C), i.e., [3, 7) (unit: °C), i.e., zone B. The first dimension parameter corresponding to the target temperature difference range is determined according to the first preset correspondence. The first-dimensional parameters corresponding to the target temperature difference range are multiple parameters. For example, the control strategies (i.e., the number of units controlled and the frequency controlled strategies) of the entire column (i.e., the column corresponding to area B) corresponding to the temperature difference range [R03, R03+4) (in °C) in Table 1 are all first-dimensional parameters, namely 12 or 131(21) and 12(21). The temperature difference change rate is compared with the temperature difference change rate range to determine the target temperature difference change rate range corresponding to the temperature difference change rate. For example, if the temperature difference change rate is 0.2 °C / min, its corresponding target temperature difference change rate range is [0, 0.5) (in °C / min), i.e., area d. The second-dimensional parameters corresponding to the target temperature difference change range are determined according to the second preset comparison relationship. The second-dimensional parameters corresponding to the target temperature difference change rate range are multiple parameters. For example, the target control strategies (i.e., the number of units controlled and the frequency control strategies) for the entire row (i.e., the row corresponding to zone d) in Table 1 corresponding to the temperature difference change rate range [0, 0.5] (unit: ℃ / min) are all second-dimensional parameters, namely 11 (21), 12 or 131 (21), 132 (21) and 133 (22). Based on the intersection of the first-dimensional parameters and the second-dimensional parameters, the corresponding target control strategy is determined, i.e., the corresponding number of units controlled and the frequency control strategy. For example, if the intersection of the first-dimensional parameters and the second-dimensional parameters is 12 or 131 (21) (i.e., the intersection of zone B and zone d in Table 1), then the number of units controlled is determined to be a constant temperature start-up control strategy or an additional unit control strategy for starting a new heat pump unit compressor, and the frequency control strategy is a full PID frequency regulation strategy.

[0093] The above-mentioned method obtains the first temperature difference of the corresponding cycle and the temperature difference change rate of two adjacent cycles by periodically detecting the average return water temperature. Based on the first temperature difference and the temperature difference change rate, the start-up quantity control strategy and frequency control strategy are determined together, realizing multi-dimensional consideration, thereby improving the accuracy of temperature control and the adaptability of the number of parallel units to the actual energy demand, and thus reducing the overall energy consumption of the parallel units.

[0094] In one embodiment, a reference table of preset comparison relationships is provided for the heating mode, as shown in Tables 3 and 4 below. The full-on control strategy is represented by 11; the constant-temperature start-up control strategy is represented by 12; the strategy of adding a new heat pump unit is represented by 131; the strategy of adding a heat pump unit's compressor when the current operating frequency of all currently running heat pump units reaches a preset maximum frequency (K01) or a limited frequency (K02) is represented by 132; the strategy of adding a heat pump unit's compressor when the current operating frequency of all currently running heat pump units reaches a preset maximum frequency (K01) or a limited high-frequency frequency (K03) is represented by 133; the strategy of reducing the compressor of a heat pump unit by shutting down is represented by 141; the strategy of reducing the compressor of a heat pump unit by shutting down when the current operating frequency meets a preset second condition is represented by 142; and the maintenance strategy is represented by 15. The full PID frequency modulation strategy is represented by 21, the fixed single-unit PID frequency modulation strategy is represented by 22; the fixed single-unit fixed frequency control strategy executing fixed frequency 1 is represented by 231, the fixed single-unit fixed frequency control strategy executing fixed frequency 2 is represented by 232, the fixed single-unit fixed frequency control strategy executing fixed frequency 3 is represented by 233, the fixed single-unit fixed frequency control strategy executing fixed frequency 4 is represented by 234, the fixed single-unit fixed frequency control strategy executing fixed frequency 5 is represented by 235; the frequency maintenance strategy is represented by 24; and the shutdown strategy is represented by 25.

[0095] Table 3:

[0096]

[0097] Table 4:

[0098]

[0099] In Tables 3 and 4, △T (°C) represents the temperature difference range, and Φ (°C / min) represents the temperature difference change rate range. R05 represents the heating start-up hysteresis value, and R06 represents the heating shutdown hysteresis. Using the preset correspondence in Tables 3 and 4, when the corresponding first temperature difference is obtained through periodic detection, it can be compared with the temperature difference range to determine the target temperature difference range corresponding to the first temperature difference. For example, if the first temperature difference is 4°C, when R05 = 3, the corresponding target temperature difference range is [R05, R05+2) (unit: °C), i.e., [3, 5) (unit: °C), i.e., zone B. The first dimension parameter corresponding to the target temperature difference range is determined based on the first preset correspondence. The first dimension parameter corresponding to the target temperature difference range consists of multiple parameters. For example, the control strategies (i.e., the number of units controlled and the frequency controlled strategies) of the entire column (i.e., the column corresponding to area B) corresponding to the temperature difference range [R05, R05+2] (unit: ℃) in Table 3 are all first dimension parameters, namely 12 or 131(21) and 12(21). The temperature difference change rate is compared with the temperature difference change rate range to determine the target temperature difference change rate range corresponding to the temperature difference change rate. For example, if the temperature difference change rate is -0.2℃ / min, the corresponding target temperature difference change rate range is (-0.5, 0] (unit: ℃ / min), i.e., area d. The second dimension parameter corresponding to the target temperature difference change range is determined according to the second preset comparison relationship. The second dimension parameter corresponding to the target temperature difference change rate range consists of multiple parameters. For example, the target control strategies (i.e., the number of units controlled and the frequency controlled strategies) of the entire row (i.e., the row corresponding to area d) corresponding to the temperature difference change rate range (-0.5, 0] (unit: ℃ / min) in Table 3 are all second dimension parameters, i.e. 11(21), 12 or 131(21), 132(21) and 133(22). Based on the intersection of the first-dimensional parameter and the second-dimensional parameter, determine the corresponding target control strategy, that is, the corresponding start-up quantity control strategy and frequency control strategy. For example, if the intersection of the first-dimensional parameter and the second-dimensional parameter is 12 or 131(21) (that is, the intersection of area B and area d in Table 1), then the start-up quantity control strategy is determined to be a constant temperature start-up control strategy or an additional start-up control strategy for a compressor of a new heat pump unit, and the frequency control strategy is a full PID frequency regulation strategy.

[0100] The above-mentioned method obtains the first temperature difference of the corresponding cycle and the temperature difference change rate of two adjacent cycles by periodically detecting the average return water temperature. Based on the first temperature difference and the temperature difference change rate, the start-up quantity control strategy and frequency control strategy are determined together, realizing multi-dimensional consideration, thereby improving the accuracy of temperature control and the adaptability of the number of parallel units to the actual energy demand, and thus reducing the overall energy consumption of the parallel units.

[0101] In one embodiment, when the first dimension parameter is within the first parameter range, the operating quantity control strategy is determined to be a full-on control strategy, and the frequency control strategy is determined to be a full PID frequency modulation strategy; for example, area A in Tables 1 and 3. When the first dimension parameter is within the second parameter range, and the second dimension parameter is within the third parameter range, the operating quantity control strategy is determined to be an added-machine control strategy, and the frequency control strategy is determined to be a full PID frequency modulation strategy; for example, the intersection of areas CD and ad in Tables 1 and 3. When the first dimension parameter is within the fourth parameter range, and the second dimension parameter is within the fifth parameter range, the operating quantity control strategy is determined to be an added-machine control strategy, and the frequency control strategy is determined to be a fixed single-machine PID frequency modulation strategy; for example, the intersection of areas E and ad in Tables 1 and 3. When the first dimension parameter is within the sixth parameter range, and the second dimension parameter is within the seventh parameter range, the operating quantity control strategy is determined to be a maintenance strategy, and the frequency control strategy is determined to be a fixed single-machine fixed-frequency control strategy; for example, the intersection of areas DE and gh in Tables 1 and 3. When the first dimension parameter is within the eighth parameter range and the second dimension parameter is within the ninth parameter range, the start-up quantity control strategy is determined to be a reduce-up control strategy, and the frequency control strategy is determined to be a full PID frequency modulation strategy; for example, the intersection of region G and region fg in Tables 2 and 4, and the intersection of region H and region ef. When the first dimension parameter is within the tenth parameter range, the frequency control strategy is determined to be a shutdown strategy, which is used to control all compressors to shut down; for example, the constant shutdown region in Tables 2 and 4.

[0102] S105. Control the start and stop of the compressor of the corresponding heat pump unit according to the start-up quantity control strategy, and adjust the frequency of the currently started compressor according to the frequency control strategy.

[0103] After determining the target control strategy for this cycle, that is, after determining the corresponding start-up quantity control strategy and frequency control strategy, the start-up and shutdown of the compressors of the corresponding heat pump units are controlled according to the start-up quantity control strategy to control the compressors of the corresponding number of heat pump units to be in operation; and the frequency of the currently started compressors is adjusted according to the frequency control strategy. For example, according to the aforementioned embodiment, it is assumed that the target control strategy for this cycle is 12 or 131 (21), that is, the start-up quantity control strategy is a constant temperature start-up control strategy or an additional start-up control strategy for a heat pump unit compressor, and the frequency control strategy is a full PID frequency regulation strategy. For example, according to the constant temperature start-up control strategy, the number of units in operation before constant temperature shutdown is determined, and the number of heat pump units in operation before constant temperature shutdown minus one is started; the frequency of the compressors is adjusted according to the preset PID frequency regulation strategy of each currently started heat pump unit according to the full PID frequency regulation strategy.

[0104] In one embodiment, after determining the number of units to be controlled as an addition control strategy and the frequency control strategy as a full PID frequency modulation strategy when the first dimension parameter is within the range of the second parameter and the second dimension parameter is within the range of the third parameter, the current operating frequency of the compressor of the currently activated heat pump unit is detected. According to the addition control strategy, when the current operating frequency meets a preset first condition, a new compressor of the heat pump unit is activated. The preset first condition is that the current operating frequency of all currently activated heat pump units reaches a preset maximum frequency, a limited frequency, or a limited high-frequency frequency, and remains so for a first preset time. The newly activated compressor is controlled to perform frequency regulation according to its own preset PID frequency modulation strategy, and the operating frequency of the other currently activated compressors is controlled to decrease to a preset fixed frequency. It should be noted that if the operating frequency of the other currently activated compressors is the minimum operating frequency, it is not necessary to decrease the preset fixed frequency; maintaining the current minimum operating frequency is sufficient.

[0105] In one embodiment, after determining that the number of units activated is controlled by a reduction-based control strategy and the frequency control strategy is controlled by a full PID frequency modulation strategy when the first dimension parameter is within the range of the eighth parameter and the second dimension parameter is within the range of the ninth parameter, the current operating frequency of the compressor of the currently activated heat pump unit is detected. According to the reduction-based control strategy, when the current operating frequency meets a preset second condition, the compressor of one heat pump unit is shut down. The preset second condition is that the current operating frequency of all currently activated heat pump units reaches a preset minimum frequency or a low-frequency limit.

[0106] It should be noted that when implementing the corresponding start-up quantity control strategy, if a heat pump unit that needs to be operated fails and shuts down, the unstarted heat pump unit will be used instead and will operate according to the corresponding frequency control strategy.

[0107] As described above, after the heat pump unit has been running for a first preset time, the average return water temperature is periodically detected. The first temperature difference is determined based on the difference between the average return water temperature and the preset target temperature. The temperature difference change rate is determined based on the difference between the first temperature difference and the second temperature difference, where the second temperature difference is the first temperature difference determined in the previous cycle. The start-up quantity control strategy and the frequency control strategy are determined based on the first temperature difference, the temperature difference change rate, and the preset comparison relationship. The start-up quantity control strategy controls the start-up and shutdown of the compressor of the corresponding heat pump unit. The frequency control strategy adjusts the frequency of the currently running compressor. By employing the aforementioned technical means, the start-up quantity control strategy and frequency control strategy can be jointly determined through two dimensions: the first temperature difference and the rate of change of temperature difference. Based on the start-up quantity control, the number of heat pump units in operation is adapted to the current load. Compared with the existing parallel operation mode where all heat pump units are in a state of operation, this embodiment, based on the start-up quantity control strategy, can shut down some inefficient heat pump units and add heat pump units when the system is overloaded, so that the number of heat pump units in operation meets the current load demand, thereby reducing the overall energy consumption of the parallel-operated heat pump units. In addition, the frequency of the currently operating compressor is adjusted according to the frequency control strategy. This embodiment uses periodic detection to obtain the first temperature difference and the rate of change of temperature difference for compressor frequency control. In the face of complex actual operating environments, the frequency control strategy can be determined based on the first temperature difference and the rate of change of temperature difference corresponding to the actual operating effect, thereby improving the accuracy of compressor frequency control of the heat pump units. Based on the improved accuracy of compressor frequency control, the load adaptability is improved and frequent start-stop situations are reduced, further reducing the overall energy consumption of the parallel-operated heat pump units.

[0108] In one embodiment, a mapping relationship between parameter codes and specific content is provided, as shown in Table 5:

[0109] Table 5:

[0110]

[0111]

[0112] In one embodiment, the preset temperature target is the heating target temperature in heating mode. For example, when the heat pump unit is currently operating in heating mode, a temperature setting signal is received, and the heating target temperature is determined based on the temperature setting signal. In heating mode, the average return water temperature of the parallel units is periodically detected, and a first temperature difference is determined based on the difference between the average return water temperature and the first target temperature. For example, the first temperature difference ΔT = R01 - T01, where R01 is the heating target temperature and T01 is the average return water temperature; the temperature difference change rate Φ = (ΔT(n-1) - ΔT) / M01; where M01 is the frequency regulation period, which can be understood as the duration of the periodic detection, and ΔT(n-1) is the first temperature difference determined in the previous period.

[0113] In one embodiment, the preset temperature target is the cooling target temperature in cooling mode. For example, when the heat pump unit is currently operating in cooling mode, a temperature setting signal is received, and the cooling target temperature is determined based on the temperature setting signal. In cooling mode, the average return water temperature of the parallel units is periodically detected, and a first temperature difference is determined based on the difference between the average return water temperature and the first target temperature. For example, the first temperature difference ΔT = T01 - R02, where R02 is the cooling target temperature and T01 is the average return water temperature; the temperature difference change rate Φ = (ΔT - ΔT(n-1)) / M01; where M01 is the frequency modulation period, which can be understood as the duration of the periodic detection, and ΔT(n-1) is the first temperature difference determined in the previous period.

[0114] In both heating and cooling modes, the average return water temperature can be periodically detected to obtain the first temperature difference and the rate of change of temperature difference for the corresponding period. Based on the preset comparison relationship (i.e., Table 1-4 above), the first temperature difference can be compared with the temperature difference interval ΔT to determine the target temperature difference interval corresponding to the first temperature difference. The rate of change of temperature difference corresponding to this period is compared with the interval of the rate of change of temperature difference to determine the target temperature difference rate of change interval corresponding to the rate of change of temperature difference. According to the column corresponding to the target temperature difference interval and the row corresponding to the target temperature difference rate of change interval, the intersecting target control strategy (e.g., 12 or 131 (21)) is determined, and the start and stop of the corresponding compressor is controlled according to the target control strategy, and the corresponding compressor is controlled to perform the corresponding frequency adjustment processing.

[0115] For example, in cooling mode, referring to Tables 1 and 2 above, assuming the first temperature difference (i.e., the second temperature difference) determined in the previous cycle is 8℃, and the first temperature difference determined in this cycle is 4℃, the difference between the two is 4℃, and the cycle time is 20 minutes, then the temperature difference change rate is 0.2℃ / min. Assuming R03 = 3, its corresponding target temperature difference range is [R03, R03+4) (in ℃), i.e., [3, 7) (in ℃), which corresponds to zone B in Table 1; the temperature difference change rate of 0.2℃ / min corresponds to zone d in Table 1. At this time, all the heat pump units in operation are already running at high frequency, but the average return water temperature is still rising, indicating that the capacity of the existing heat pump units is insufficient to meet the current demand. In order to ensure the stable operation of the parallel units as a whole and prevent overheating from causing unit damage or performance degradation, it is necessary to immediately start the compressor of an additional heat pump unit to increase the cooling capacity. Therefore, the corresponding start-up quantity control strategy is determined to be either a constant temperature start-up control strategy or a new compressor start-up control strategy for a heat pump unit, and the frequency control strategy is a full PID frequency regulation strategy.

[0116] For example, in cooling mode, referring to Tables 1 and 2 above, if the first temperature difference is in range A, it means that the required capacity is higher and all heat pump units need to be turned on. Therefore, the corresponding start-up quantity control strategy is determined to be the full-on control strategy, and the frequency control strategy is the full PID frequency regulation strategy, in order to provide the maximum cooling capacity supply.

[0117] For example, in cooling mode, referring to Tables 1 and 2 above, when the average return water temperature has dropped to the range of the preset target temperature (i.e., the target cooling temperature), that is, the first temperature difference value is within the F interval. Then, if the temperature difference change rate is detected to fluctuate within the ae interval and the average return water temperature shows an upward trend, the number of currently operating heat pump units and the operating frequency of each compressor can be kept unchanged to ensure stable system operation. That is, the number of units operated is controlled as a maintenance strategy, and the frequency is controlled as a frequency maintenance strategy.

[0118] For example, in cooling mode, referring to Tables 1 and 2 above, when the average return water temperature drops to the FH range and the temperature difference change rate is in the fh range where the cooling rate is relatively fast, it means that the current average return water temperature is close to the demand. Therefore, the frequency can be quickly reduced and the number of heat pump units can be reduced as needed.

[0119] For example, in cooling mode, referring to Tables 1 and 2 above, if the first temperature difference is in the G range and the cooling speed is relatively fast, that is, the temperature difference change rate is in the g range, it means that the current capacity demand is not high, and the number of operating heat pump units can be reduced. That is, the operating quantity control strategy is determined to be: when the current operating frequency meets the preset second condition, the compressor of one heat pump unit is shut down as a reduction control strategy; and the frequency control strategy is determined to be a full PID control strategy.

[0120] For example, in cooling mode, referring to Tables 1 and 2 above, when the first temperature difference decreases to the constant stop range, all heat pump units are controlled to stop, that is, the compressors of all heat pump units are turned off.

[0121] As described above, by dynamically adjusting the number of parallel units and the compressor frequency based on the rate of change of the average return water temperature, the number of heat pump units that can be turned on can be quickly locked, thereby improving the adaptability of the parallel units to changes in the external environment, making energy consumption more rational, and thus enhancing the user experience. Secondly, the parallel operation control method of heat pump units provided in this embodiment results in smaller temperature fluctuations, thus making the indoor and outdoor temperature difference more stable, thereby reducing the number of unnecessary switching operations and extending the service life of the equipment.

[0122] As described above, during the parallel operation and control of heat pump units, after the first preset time of operation, the average return water temperature of the heat pump units is periodically detected. The first temperature difference is determined based on the difference between the average return water temperature and the preset target temperature. The temperature difference change rate is determined based on the difference between the first temperature difference and the second temperature difference, where the second temperature difference is the first temperature difference determined in the previous cycle. The start-up quantity control strategy and frequency control strategy are determined based on the first temperature difference, the temperature difference change rate, and the preset comparison relationship. The start-up quantity control strategy controls the start-up and shutdown of the compressors of the corresponding heat pump units. The frequency control strategy adjusts the frequency of the currently running compressors. By employing the aforementioned technical means, the start-up quantity control strategy and frequency control strategy can be jointly determined through two dimensions: the first temperature difference and the rate of change of temperature difference. Based on the start-up quantity control, the number of heat pump units in operation is adapted to the current load. Compared with the existing parallel operation mode where all heat pump units are in a state of operation, this embodiment, based on the start-up quantity control strategy, can shut down some inefficient heat pump units and add heat pump units when the system is overloaded, so that the number of heat pump units in operation meets the current load demand, thereby reducing the overall energy consumption of the parallel-operated heat pump units. In addition, the frequency of the currently operating compressor is adjusted according to the frequency control strategy. This embodiment uses periodic detection to obtain the first temperature difference and the rate of change of temperature difference for compressor frequency control. In the face of complex actual operating environments, the frequency control strategy can be determined based on the first temperature difference and the rate of change of temperature difference corresponding to the actual operating effect, thereby improving the accuracy of compressor frequency control of the heat pump units. Based on the improved accuracy of compressor frequency control, the load adaptability is improved and frequent start-stop situations are reduced, further reducing the overall energy consumption of the parallel-operated heat pump units.

[0123] Based on the above embodiments, Figure 2 A schematic diagram of a parallel operation control device for a heat pump unit provided in an embodiment of this application. (Reference) Figure 2 The parallel operation control device for heat pump units provided in this embodiment is used for heat pump units. This parallel operation control device for heat pump units is used for parallel units, which are composed of multiple heat pump units connected in parallel. The parallel operation control device for heat pump units specifically includes: a start-up module 21, a temperature difference determination module 22, a rate of change determination module 23, a strategy determination module 24, and a control module 25.

[0124] Among them, the power-on module 21 is used to receive the power-on command and execute the power-on strategy in response to the power-on command;

[0125] The temperature difference determination module 22 is used to periodically detect the average return water temperature of the parallel units after running for a preset time, and determine the first temperature difference based on the difference between the average return water temperature and the preset target temperature.

[0126] The rate of change determination module 23 is used to determine the rate of change of temperature difference based on the difference between the first temperature difference and the second temperature difference, wherein the second temperature difference is the first temperature difference determined in the previous cycle.

[0127] The strategy determination module 24 is used to determine the start-up quantity control strategy and frequency control strategy based on the first temperature difference, the temperature difference change rate, and the preset comparison relationship. The start-up quantity control strategy includes full-on control strategy, constant temperature start-up control strategy, adding control strategy, reducing control strategy and maintenance strategy. The frequency control strategy includes full PID frequency modulation strategy, fixed single-unit PID frequency modulation strategy, fixed single-unit fixed frequency control strategy, maintenance frequency strategy and shutdown strategy.

[0128] The control module 25 is used to control the start and stop of the compressor of the corresponding heat pump unit according to the start-up quantity control strategy, and to adjust the frequency of the currently started compressor according to the frequency control strategy.

[0129] In one embodiment, the power-on module 21 includes: an instruction receiving submodule, a first temperature difference determination submodule, a power-on submodule, and a frequency control submodule;

[0130] The instruction receiving submodule is used to receive the power-on instruction and, in response to the power-on instruction, detect the average return water temperature of the parallel units;

[0131] The first temperature difference determination submodule is used to determine the first temperature difference based on the difference between the average return water temperature and the preset target temperature.

[0132] The startup submodule is used to control the compressors of a first number of heat pump units to start when the first temperature difference is greater than a first preset threshold in cooling mode or when the first temperature difference is less than a second preset threshold in heating mode. The first number is the total number of parallel units minus one.

[0133] The frequency control submodule is used to control the compressor frequency according to the preset PID frequency control strategy of each currently running heat pump unit.

[0134] In one embodiment, the strategy determination module 24 includes: a first dimension parameter determination submodule, a second dimension parameter determination submodule, and a control strategy determination submodule;

[0135] The first dimension parameter determination submodule is used to determine the first dimension parameter based on the first temperature difference and the preset comparison relationship.

[0136] The second-dimensional parameter determination submodule is used to determine the second-dimensional parameters based on the temperature difference change rate and the preset comparison relationship.

[0137] The control strategy determination submodule is used to determine the start-up quantity control strategy and frequency control strategy based on the intersection of the first dimension parameters and the second dimension parameters.

[0138] In one embodiment, the first dimension parameter determination submodule includes: a temperature difference range preset unit, a target temperature difference range determination unit, and a first dimension parameter determination unit;

[0139] Temperature difference range preset unit is used to preset temperature difference range, and the temperature difference range has a first preset correspondence relationship with the first dimension parameter;

[0140] The target temperature difference range determination unit is used to compare the first temperature difference with the temperature difference range to determine the target temperature difference range corresponding to the first temperature difference.

[0141] The first dimension parameter determination unit is used to determine the first dimension parameter corresponding to the target temperature difference range according to the first preset comparison relationship;

[0142] The second-dimensional parameter determination submodule includes: a temperature difference change rate interval preset unit, a target temperature difference change rate interval determination unit, and a second-dimensional parameter determination unit;

[0143] The temperature difference change rate range preset unit is used to preset the temperature difference change rate range, and the temperature difference change rate range has a second preset correspondence with the second dimension parameter;

[0144] The target temperature difference change rate range determination unit is used to compare the temperature difference change rate with the temperature difference change rate range to determine the target temperature difference change rate range corresponding to the temperature difference change rate.

[0145] The second-dimensional parameter determination unit is used to determine the second-dimensional parameters corresponding to the target temperature difference change rate range based on the second preset comparison relationship.

[0146] In one embodiment, the control strategy determination submodule includes: a first control unit, a second control unit, a third control unit, a fourth control unit, a fifth control unit, and a sixth control unit;

[0147] The first control unit is used to determine the number of units turned on as a full-on control strategy and the frequency control strategy as a full PID frequency modulation strategy when the first dimension parameter is within the range of the first parameter.

[0148] The second control unit is used to determine the number of machines to be controlled as an increase control strategy and the frequency control strategy as a full PID frequency modulation strategy when the first dimension parameter is within the range of the second parameter and the second dimension parameter is within the range of the third parameter.

[0149] The third control unit is used to determine the start-up control strategy as the add-on control strategy and the frequency control strategy as the fixed single-unit PID frequency modulation strategy when the first dimension parameter is in the range of the fourth parameter and the second dimension parameter is in the range of the fifth parameter.

[0150] The fourth control unit is used to determine the number of units turned on as a maintenance strategy and the frequency control strategy as a fixed single-unit fixed frequency control strategy when the first dimension parameter is in the range of the sixth parameter and the second dimension parameter is in the range of the seventh parameter.

[0151] The fifth control unit is used to determine the number of machines to be controlled as a reduction control strategy and the frequency control strategy as a full PID frequency modulation strategy when the first dimension parameter is in the range of the eighth parameter and the second dimension parameter is in the range of the ninth parameter.

[0152] The sixth control unit is used to determine the frequency control strategy as a shutdown strategy when the first dimension parameter is within the range of the tenth parameter. The shutdown strategy is used to control all compressors to shut down.

[0153] In one embodiment, the parallel operation control device for the heat pump unit further includes: a frequency detection module;

[0154] The frequency detection module is used to detect the current operating frequency of the compressor of the currently running heat pump unit;

[0155] The control module 25 includes: a power-on control submodule and a frequency control submodule;

[0156] The start-up control submodule is used to add a compressor of a heat pump unit to start when the current operating frequency meets a preset first condition, according to the add-unit control strategy. The preset first condition is that the current operating frequency of all currently started heat pump units reaches a preset maximum frequency, a limited frequency, or a limited high frequency, and this lasts for a first preset time.

[0157] The frequency control submodule is used to control newly started compressors to adjust their frequency according to their own preset PID frequency regulation strategy, and to control the operating frequency of other currently started compressors to be reduced to a preset fixed frequency.

[0158] In one embodiment, based on the foregoing implementation, the frequency detection module is further configured to detect the current operating frequency of the compressor of the currently activated heat pump unit;

[0159] The start-up control submodule is also used to shut down the compressor of a heat pump unit when the current operating frequency meets a preset second condition, according to the reduce-load control strategy. The preset second condition is that the current operating frequency of all currently running heat pump units reaches a preset minimum frequency or a low-frequency limit.

[0160] The parallel operation control device for heat pump units provided in this application embodiment can be used to execute the parallel operation control method for heat pump units provided in the above embodiment, and has corresponding functions and beneficial effects.

[0161] This application provides a parallel operation control device for heat pump units, referring to... Figure 3 The parallel operation control equipment for the heat pump unit includes: a processor 31, a memory 32, a communication module 33, an input device 34, and an output device 35. The number of processors and the number of memories in the parallel operation control equipment can be one or more. The processor, memory, communication module, input device, and output device of the parallel operation control equipment can be connected via a bus or other means.

[0162] The memory 32, as a computer-readable storage medium, can be used to store software programs, computer-executable programs, and modules, such as the program instructions / modules corresponding to the heat pump unit parallel operation control method described in any embodiment of this application (e.g., the start-up module, temperature difference determination module, rate of change determination module, strategy determination module, and control module in the heat pump unit parallel operation control device). The memory may primarily include a program storage area and a data storage area. The program storage area may store the operating system and at least one application program required for a function; the data storage area may store data created based on the use of the device, etc. Furthermore, the memory may include high-speed random access memory and non-volatile memory, such as at least one disk storage device, flash memory device, or other non-volatile solid-state storage device. In some instances, the memory may further include memory remotely located relative to the processor, and these remote memories can be connected to the device via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0163] The communication module 33 is used for data transmission.

[0164] The processor 31 executes various functional applications and data processing of the device by running software programs, instructions and modules stored in the memory, thereby realizing the above-mentioned parallel operation control method of the heat pump unit.

[0165] Input device 34 can be used to receive input digital or character information, and to generate key signal inputs related to user settings and function control of the device. Output device 35 may include display devices such as a display screen.

[0166] The heat pump unit parallel operation control equipment provided above can be used to execute the heat pump unit parallel operation control method provided in the above embodiments, and has corresponding functions and beneficial effects.

[0167] This application embodiment also provides a storage medium for storing computer-executable instructions. When executed by a computer processor, the computer-executable instructions are used to execute a method for controlling the parallel operation of heat pump units. This method includes: receiving a start-up command; responding to the start-up command and executing a start-up strategy; after running for a first preset time, periodically detecting the average return water temperature of the parallel units and determining a first temperature difference based on the difference between the average return water temperature and a preset target temperature; determining the temperature difference change rate based on the difference between the first temperature difference and a second temperature difference, wherein the second temperature difference is determined in the previous cycle. First temperature difference; based on the first temperature difference, the rate of change of temperature difference, and the preset comparison relationship, determine the start-up quantity control strategy and the frequency control strategy. The start-up quantity control strategy includes full-on control strategy, constant temperature start-up control strategy, adding control strategy, reducing control strategy, and maintenance strategy. The frequency control strategy includes full PID frequency modulation strategy, fixed single-unit PID frequency modulation strategy, fixed single-unit fixed frequency control strategy, maintenance frequency strategy, and shutdown strategy. Control the start-up and shutdown of the compressor of the corresponding heat pump unit according to the start-up quantity control strategy, and adjust the frequency of the currently running compressor according to the frequency control strategy.

[0168] Storage medium – any type of memory device or storage device. The term “storage medium” is intended to include: mounting media, such as CD-ROM, floppy disk, or magnetic tape devices; computer system memory or random access memory, such as DRAM, DDR RAM, SRAM, EDO RAM, Rambus RAM, etc.; non-volatile memory, such as flash memory, magnetic media (e.g., hard disk or optical storage); registers or other similar types of memory elements, etc. Storage medium may also include other types of memory or combinations thereof. Furthermore, storage medium may reside in a first computer system in which the program is executed, or it may reside in a different second computer system connected to the first computer system via a network (such as the Internet). The second computer system can provide program instructions to the first computer for execution. The term “storage medium” can include two or more storage media residing in different locations (e.g., in different computer systems connected via a network). Storage medium may store program instructions (e.g., specifically implemented as a computer program) executable by one or more processors.

[0169] Of course, the storage medium for storing computer-executable instructions provided in the embodiments of this application is not limited to the heat pump unit parallel operation control method as described above, but can also execute related operations in the heat pump unit parallel operation control method provided in any embodiment of this application.

[0170] The heat pump unit parallel operation control device, storage medium, and heat pump unit parallel operation control equipment provided in the above embodiments can execute the heat pump unit parallel operation control method provided in any embodiment of this application. For technical details not described in detail in the above embodiments, please refer to the heat pump unit parallel operation control method provided in any embodiment of this application.

[0171] The above description is merely a preferred embodiment and the technical principles employed in this application. This application is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions that can be made by those skilled in the art will not depart from the scope of protection of this application. Therefore, although this application has been described in detail through the above embodiments, this application is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of this application, the scope of which is determined by the scope of the claims.

Claims

1. A method for controlling parallel operation of heat pump units, characterized in that, For use in parallel units, wherein the parallel units are composed of multiple heat pump units connected in parallel, the method includes: Receive a power-on command and, in response to the power-on command, execute a power-on strategy; After running for a first preset time, the average return water temperature of the parallel units is periodically detected, and a first temperature difference is determined based on the difference between the average return water temperature and the preset target temperature. The rate of change of temperature difference is determined based on the difference between the first temperature difference and the second temperature difference, where the second temperature difference is the first temperature difference determined in the previous cycle. Based on the first temperature difference, the rate of change of the temperature difference, and the preset comparison relationship, the start-up quantity control strategy and the frequency control strategy are determined. The start-up quantity control strategy includes a full-on control strategy, a constant temperature start-up control strategy, a machine addition control strategy, a machine reduction control strategy, and a maintenance strategy. The frequency control strategy includes a full PID frequency modulation strategy, a fixed single-unit PID frequency modulation strategy, a fixed single-unit fixed frequency control strategy, a frequency maintenance strategy, and a shutdown strategy. The start-up and shutdown of the compressors of the corresponding heat pump units are controlled according to the start-up quantity control strategy, and the frequency of the currently started compressors is adjusted according to the frequency control strategy. The step of determining the start-up quantity control strategy and frequency control strategy based on the first temperature difference, the temperature difference change rate, and a preset comparison relationship includes: By integrating the first and second preset comparison relationships, a third preset comparison relationship with two complete dimensions is obtained; Based on the first temperature difference and the third preset comparison relationship, the first dimension parameter is determined. The first dimension parameter is the parameter of the power-on quantity control strategy and the frequency control strategy. Based on the temperature difference change rate and the third preset comparison relationship, the second dimension parameter is determined. The second dimension parameter is the parameter of the start-up quantity control strategy and the frequency control strategy. Based on the intersection of the first dimension parameter and the second dimension parameter, the power-on quantity control strategy and the frequency control strategy are determined; The step of determining the first dimension parameter based on the first temperature difference and the third preset comparison relationship includes: A preset temperature difference range is defined, and the temperature difference range has a first preset correlation relationship with the first dimension parameter. The first temperature difference is compared with the temperature difference range to determine the target temperature difference range corresponding to the first temperature difference; The first dimension parameter corresponding to the target temperature difference range is determined according to the first preset comparison relationship; The step of determining the second dimension parameter based on the temperature difference change rate and the third preset comparison relationship includes: A preset temperature difference change rate range is defined, and the temperature difference change rate range has a second preset correlation relationship with the second dimension parameter. By comparing the temperature difference change rate with the temperature difference change rate range, the target temperature difference change rate range corresponding to the temperature difference change rate is determined; The second dimension parameter corresponding to the target temperature difference change rate range is determined based on the second preset comparison relationship.

2. The method according to claim 1, characterized in that, The receiving of the power-on command and the execution of the power-on strategy in response to the power-on command include: Upon receiving a power-on command, and in response to the power-on command, detect the average return water temperature of the parallel units; The first temperature difference is determined based on the difference between the average return water temperature and the preset target temperature; In cooling mode and when the first temperature difference is greater than the first preset threshold, or in heating mode and when the first temperature difference is less than the second preset threshold, the compressors of a first number of heat pump units are controlled to start, and the first number is the total number of the parallel units minus one. The compressor frequency is adjusted according to the preset PID frequency regulation strategy of each currently activated heat pump unit.

3. The method according to claim 1, characterized in that, The step of determining the power-on quantity control strategy and frequency control strategy based on the intersection of the first dimension parameter and the second dimension parameter includes: When the first dimension parameter is within the range of the first parameter, the power-on quantity control strategy is determined to be the full-on control strategy, and the frequency control strategy is determined to be the full PID frequency modulation strategy. When the first dimension parameter is within the range of the second parameter, and the second dimension parameter is within the range of the third parameter, the power-on quantity control strategy is determined to be the power-on addition control strategy, and the frequency control strategy is determined to be the full PID frequency modulation strategy. When the first dimension parameter is within the range of the fourth parameter and the second dimension parameter is within the range of the fifth parameter, the power-on control strategy is determined to be the power-on addition control strategy, and the frequency control strategy is determined to be the fixed single-unit PID frequency modulation strategy. When the first dimension parameter is within the range of the sixth parameter and the second dimension parameter is within the range of the seventh parameter, the power-on quantity control strategy is determined to be the maintenance strategy, and the frequency control strategy is determined to be the fixed single-unit fixed frequency control strategy. When the first dimension parameter is within the range of the eighth parameter and the second dimension parameter is within the range of the ninth parameter, the power-on quantity control strategy is determined to be the power reduction control strategy, and the frequency control strategy is determined to be the full PID frequency modulation strategy. When the first dimension parameter is within the range of the tenth parameter, the frequency control strategy is determined to be the shutdown strategy, which is used to control all compressors to shut down.

4. The method according to claim 3, characterized in that, The step of determining the number of machines to be controlled as the addition control strategy and the frequency control strategy as the full PID frequency modulation strategy when the first dimension parameter is within the range of the second parameter and the second dimension parameter is within the range of the third parameter includes: Detect the current operating frequency of the compressor in the currently running heat pump unit; The step of controlling the start-up and shutdown of the compressor of the corresponding heat pump unit according to the start-up quantity control strategy includes: According to the added unit control strategy, when the current operating frequency meets the preset first condition, a compressor of a heat pump unit is added and started. The preset first condition is that the current operating frequency of all currently started heat pump units reaches the preset maximum frequency, the limited frequency, or the limited high frequency, and this continues for a first preset time. The newly activated compressor is controlled to adjust its frequency according to its own preset PID frequency regulation strategy, and the operating frequency of other currently activated compressors is controlled to be reduced to a preset fixed frequency.

5. The method according to claim 3, characterized in that, After determining that the number of machines activated is controlled as the reduction control strategy and the frequency control strategy is controlled as the full PID frequency modulation strategy when the first dimension parameter is in the range of the eighth parameter and the second dimension parameter is in the range of the ninth parameter, the process includes: Detect the current operating frequency of the compressor in the currently running heat pump unit; The step of controlling the start-up and shutdown of the compressor of the corresponding heat pump unit according to the start-up quantity control strategy includes: According to the reduction control strategy, when the current operating frequency meets the preset second condition, the compressor of one heat pump unit is shut down. The preset second condition is that the current operating frequency of all currently running heat pump units reaches a preset minimum frequency or a low-frequency limit.

6. A parallel operation control device for heat pump units, characterized in that, For use in parallel units, wherein the parallel units are composed of multiple heat pump units connected in parallel, the device includes: A power-on module is used to receive a power-on command and, in response to the power-on command, execute a power-on strategy; The temperature difference determination module is used to periodically detect the average return water temperature of the parallel units after running for a preset time, and determine the first temperature difference based on the difference between the average return water temperature and the preset target temperature. The rate of change determination module is used to determine the rate of change of temperature difference based on the difference between the first temperature difference and the second temperature difference, wherein the second temperature difference is the first temperature difference determined in the previous cycle. The strategy determination module is used to determine the start-up quantity control strategy and the frequency control strategy based on the first temperature difference, the temperature difference change rate, and a preset comparison relationship. The start-up quantity control strategy includes a full-on control strategy, a constant temperature start-up control strategy, an add-machine control strategy, a reduce-machine control strategy, and a maintenance strategy. The frequency control strategy includes a full PID frequency modulation strategy, a fixed single-unit PID frequency modulation strategy, a fixed single-unit fixed frequency control strategy, a frequency maintenance strategy, and a shutdown strategy. The control module is used to control the start and stop of the compressor of the corresponding heat pump unit according to the start-up quantity control strategy, and to adjust the frequency of the currently started compressor according to the frequency control strategy. The strategy determination module includes: a first-dimensional parameter determination submodule, a second-dimensional parameter determination submodule, and a control strategy determination submodule; The first dimension parameter determination submodule is used to integrate the first preset comparison relationship and the second preset comparison relationship to obtain a complete third preset comparison relationship in two dimensions; the first dimension parameter is determined based on the first temperature difference and the third preset comparison relationship, and the first dimension parameter is the parameter of the start-up quantity control strategy and the frequency control strategy. The second-dimensional parameter determination submodule is used to determine the second-dimensional parameters based on the temperature difference change rate and the third preset comparison relationship. The second-dimensional parameters are the parameters of the start-up quantity control strategy and the frequency control strategy. The control strategy determination submodule is used to determine the start-up quantity control strategy and frequency control strategy based on the intersection of the first dimension parameters and the second dimension parameters. The first-dimensional parameter determination submodule includes: a temperature difference range preset unit, a target temperature difference range determination unit, and a first-dimensional parameter determination unit; Temperature difference range preset unit is used to preset temperature difference range, and the temperature difference range has a first preset correspondence with the first dimension parameter; The target temperature difference range determination unit is used to compare the first temperature difference with the temperature difference range to determine the target temperature difference range corresponding to the first temperature difference. The first dimension parameter determination unit is used to determine the first dimension parameter corresponding to the target temperature difference range according to the first preset comparison relationship; The second-dimensional parameter determination submodule includes: a temperature difference change rate interval preset unit, a target temperature difference change rate interval determination unit, and a second-dimensional parameter determination unit; The temperature difference change rate range preset unit is used to preset the temperature difference change rate range, and the temperature difference change rate range has a second preset correspondence with the second dimension parameter; The target temperature difference change rate range determination unit is used to compare the temperature difference change rate with the temperature difference change rate range to determine the target temperature difference change rate range corresponding to the temperature difference change rate. The second-dimensional parameter determination unit is used to determine the second-dimensional parameters corresponding to the target temperature difference change rate range based on the second preset comparison relationship.

7. A parallel operation control device for heat pump units, characterized in that, include: Memory and one or more processors; The memory is used to store one or more programs; When the one or more programs are executed by the one or more processors, the one or more processors implement the method as described in any one of claims 1-5.

8. A storage medium for storing computer-executable instructions, characterized in that, The computer-executable instructions, when executed by a processor, are used to perform the method as described in any one of claims 1-5.

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