Heat pump unit joint control method and system

Abstract

The invention relates to the technical field of heat pump equipment, and discloses a heat pump unit joint control method and system.The method comprises the steps that based on a temperature difference interval corresponding to the difference between a target water outlet temperature and a current water inlet temperature, the mapping relation between the temperature difference interval and a first correction coefficient is searched, and the first correction coefficient of a heat pump unit is determined; based on the current environment temperature, a second correction coefficient of the heat pump unit is determined; determining an initial starting number based on the first correction coefficient, the second correction coefficient and the total number of the units; and the heat pump units with the initial starting number are controlled to be started and run. The mapping relation is searched based on the corresponding temperature difference interval, it is guaranteed that correction of the first correction coefficient can reflect the requirement for the starting number of the heat pump unit by the actual load requirement, the starting number is further corrected in combination with the influence of the environment temperature on the actual load requirement, and the initial starting number can meet the current load requirement; the joint control system can reach a stable state at the initial starting stage, the stability of the system is improved, and temperature fluctuation is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of heat pump equipment, and in particular to a heat pump unit joint control method and system. Background Art

[0002] The joint control system of the heat pump unit mainly controls the start and stop of the heat pump unit in the system and controls the operating frequency of the heat pump unit so that the system can meet the temperature requirements of the user. At present, the joint control system mainly controls the heat pump unit according to the difference between the actual outlet water temperature and the temperature set by the user; however, when the joint control system of the heat pump unit is turned on, all the heat pump units are often started synchronously, and then the number of working units of the heat pump unit is adjusted according to the difference between the actual outlet water temperature and the set temperature. However, under different ambient temperatures, there may be a large difference between the actual outlet water temperature and the temperature set by the user, resulting in different heat required for heating. If all heat pump units are controlled to start synchronously each time, the heating amount will not match the required heat, and it may cause the heat pump unit to start and stop frequently during subsequent operation, resulting in poor system stability and large temperature control fluctuations. Summary of the invention

[0003] The first technical problem solved by the present invention is to provide a heat pump unit joint control method, which effectively solves the problem that the joint control system of the heat pump unit has poor stability and large temperature control fluctuations.

[0004] The second technical problem solved by the present invention is to provide a heat pump unit joint control system, which effectively solves the problems of poor stability and large temperature control fluctuations in the heat pump unit joint control system.

[0005] The first technical problem mentioned above is solved by the following technical solution:

[0006] A heat pump unit joint control method is applied to a heat pump unit joint control system, wherein the heat pump unit joint control system includes a plurality of heat pump units; the method includes:

[0007] In response to the heat pump joint control system being started, based on the temperature difference interval corresponding to the difference between the target outlet water temperature and the current inlet water temperature, a mapping relationship between the temperature difference interval and the first correction coefficient is searched to determine the first correction coefficient of the heat pump unit;

[0008] Based on the current ambient temperature, determining a second correction coefficient of the heat pump unit;

[0009] Determine the initial startup quantity based on the first correction coefficient, the second correction coefficient and the total number of heat pump units;

[0010] Control the initial number of heat pump units to start and run.

[0011] Compared with the background technology, the heat pump unit joint control method of the present invention has the following beneficial effects: a mapping relationship is established between the temperature difference interval corresponding to the difference between the target water outlet temperature and the current water inlet temperature and the first correction coefficient, and the mapping relationship is searched based on the temperature difference interval corresponding to the difference between the current target water outlet temperature and the current water inlet temperature to determine the first correction coefficient, to ensure that the correction of the total number of units by the first correction coefficient can reflect the actual load demand for the start-up number of heat pump units, to determine the second correction coefficient based on the current ambient temperature, and then to further correct the start-up number of heat pump units in combination with the influence of the ambient temperature on the actual load demand, so that the initial start-up number determined based on the first correction coefficient, the second correction coefficient and the total number of units can meet the current load demand, so that the joint control system can reach a relatively stable state at the initial startup, thereby reducing the frequent start and stop of the heat pump units, improving system stability, and reducing temperature fluctuations.

[0012] In one embodiment, determining a second correction coefficient of the heat pump unit based on the current ambient temperature includes:

[0013] Determine the temperature range corresponding to the current ambient temperature;

[0014] A search is performed based on a mapping relationship between the temperature interval and the second correction coefficient to determine the second correction coefficient corresponding to the temperature interval.

[0015] In one embodiment, determining the initial startup quantity based on the first correction coefficient, the second correction coefficient, and the total number of heat pump units includes:

[0016] Multiply the first correction coefficient, the second correction coefficient and the total number of units to obtain the initial opening quantity.

[0017] In one embodiment, after the heat pump units with the initial startup quantity are started and run, the method further comprises:

[0018] Obtain the current outlet water temperature, and determine the current temperature difference based on the difference between the target outlet water temperature and the current outlet water temperature;

[0019] Based on the size relationship between the current temperature difference and the temperature difference threshold, the start and stop and / or operating frequency of the heat pump unit are controlled.

[0020] In one embodiment, the temperature difference threshold includes a first temperature difference threshold; based on the magnitude relationship between the current temperature difference and the temperature difference threshold, controlling the start and stop and / or operating frequency of the heat pump unit includes:

[0021] If the current temperature difference is less than or equal to the first temperature difference threshold, a preset number of heat pump units are controlled to shut down for a first preset time period.

[0022] In one embodiment, the temperature difference threshold includes a second temperature difference threshold and a third temperature difference threshold, the second temperature difference threshold is greater than the first temperature difference threshold, and the second temperature difference threshold is greater than the third temperature difference threshold; based on the magnitude relationship between the current temperature difference and the temperature difference threshold, controlling the start and stop and / or operating frequency of the heat pump unit includes:

[0023] If the current temperature difference is between the third temperature difference threshold and the second temperature difference threshold, the heat pump unit is controlled to continue operating according to the current operating state.

[0024] In one embodiment, the temperature difference threshold includes a second temperature difference threshold, and the second temperature difference threshold is greater than the first temperature difference threshold; based on the magnitude relationship between the current temperature difference and the temperature difference threshold, controlling the start and stop and / or operating frequency of the heat pump unit includes:

[0025] If the current temperature difference is greater than or equal to the second temperature difference threshold after running for the second preset time, and the number of units started is less than the total number of units, then a preset number of heat pump units are controlled to start;

[0026] If the current temperature difference is greater than or equal to the second temperature difference threshold after running for the second preset time, and the number of units started is equal to the total number of units, the heat pump unit is controlled to continue running according to the current operating state.

[0027] In one embodiment, the temperature difference threshold includes a first temperature difference threshold and a third temperature difference threshold, the third temperature difference threshold is greater than the first temperature difference threshold, and the third temperature difference threshold is less than the second temperature difference threshold; based on the magnitude relationship between the current temperature difference and the temperature difference threshold, controlling the start and stop and / or operating frequency of the heat pump unit includes:

[0028] If the current temperature difference is between the first temperature difference threshold and the third temperature difference threshold after running for the second preset time, the running time of the heat pump units is obtained, and the heat pump unit with the longest running time is determined as the target unit;

[0029] The operating frequency of the target unit is controlled to decrease by a preset frequency and maintained for a third preset time period.

[0030] In one embodiment, the temperature difference threshold further includes a second temperature difference threshold and a fourth temperature difference threshold, the second temperature difference threshold is greater than the fourth temperature difference threshold, and the fourth temperature difference threshold is greater than the third temperature difference threshold; after controlling the operating frequency of the target unit to reduce the preset frequency, it also includes:

[0031] Update the current outlet water temperature, and based on the difference between the target outlet water temperature and the updated current outlet water temperature, update the current temperature difference;

[0032] If the updated current temperature difference is between the fourth temperature difference threshold and the second temperature difference threshold, the operating frequency of the target unit is increased by the preset frequency and maintained for the third preset time period.

[0033] The above second technical problem is solved by the following technical solution:

[0034] A heat pump unit joint control system comprises a plurality of heat pump units and a controller; the controller is used to execute any of the heat pump unit joint control methods described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0036] Figure 1 It is a flow chart of a heat pump unit joint control method according to an embodiment of the present invention;

[0037] Figure 2 It is a flow chart of controlling the start and stop and / or operating frequency of a heat pump unit in a heat pump unit joint control method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0039] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the feature. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0040] The joint control system of the heat pump unit mainly controls the start and stop of the heat pump unit in the system, and controls the operating frequency of the heat pump unit, so that the system can meet the temperature requirements of the user. At present, the joint control system mainly controls the heat pump unit based on the difference between the actual outlet water temperature and the temperature set by the user; however, when the system is initially started, there may be a large difference between the actual outlet water temperature and the set temperature, resulting in an inability to accurately determine the initial start-up number of the heat pump unit, and it is also impossible to quickly adjust the system to a state that can meet the user's temperature requirements at the initial startup, resulting in frequent start-ups and stops of the heat pump unit during subsequent operation, resulting in poor system stability and large temperature control fluctuations.

[0041] Based on this, an embodiment of the present invention provides a joint control method for a heat pump unit, which establishes a mapping relationship between the temperature difference interval corresponding to the difference between the target outlet water temperature and the current inlet water temperature and the first correction coefficient, and searches the mapping relationship based on the temperature difference interval corresponding to the difference between the current target outlet water temperature and the current inlet water temperature to determine the first correction coefficient, to ensure that the correction of the total number of units by the first correction coefficient can reflect the actual load demand for the start-up quantity of the heat pump unit, and to determine the second correction coefficient based on the current ambient temperature, so as to further correct the start-up quantity of the heat pump unit in combination with the influence of the ambient temperature on the actual load demand, so that the initial start-up quantity determined based on the first correction coefficient, the second correction coefficient and the total number of units can meet the current load demand, so that the joint control system can reach a relatively stable state at the initial startup, thereby reducing the frequent startup of the heat pump unit, improving the system stability and reducing temperature fluctuations.

[0042] Combine the following Figure 1 to Figure 2 , describing an embodiment of the present invention.

[0043] According to an embodiment of the present invention, on the one hand, a heat pump unit joint control method is provided, and the heat pump unit joint control method is applied to a heat pump unit joint control system, and the heat pump unit joint control system includes multiple heat pump units; at the same time, the multiple heat pump units are respectively communicated with the controller, and the controller uniformly controls and coordinates the multiple heat pump units, thereby forming a master-slave control system, avoiding the host failure causing all heat pump units in the heat pump unit joint control system to be unusable, thereby improving system reliability. Figure 1 is a flow chart of a heat pump unit joint control method according to an embodiment of the present invention, such as Figure 1 As shown, the method includes:

[0044] Step 110: In response to the start-up of the heat pump joint control system, based on the temperature difference interval corresponding to the difference between the target outlet water temperature and the current inlet water temperature, a mapping relationship between the temperature difference interval and the first correction coefficient is searched to determine the first correction coefficient of the heat pump unit.

[0045] In an embodiment of the present invention, in response to the heat pump linkage control system, the initial startup number of the heat pump units is first determined, and the initial startup number is the number of heat pump units turned on when the heat pump linkage control system is initially started. The target outlet water temperature is the required temperature set by the user, and the current inlet water temperature is the temperature of the cold water input into the system when the heat pump linkage control system is started; the target outlet water temperature is subtracted from the current inlet water temperature to determine the current demand load, and thus the initial startup number is determined based on the current demand load. Among them, the initial startup number can be assumed to be the total number of heat pump units, and the first correction coefficient corresponding to the current demand load is determined by the target outlet water temperature and the current inlet water temperature, and the total number of units is proportionally corrected to obtain the initial startup number.

[0046] In an embodiment of the present invention, there is a mapping relationship between the difference between the target water outlet temperature and the current water inlet temperature and the first correction coefficient. The difference between the target water outlet temperature and the current water inlet temperature and the first correction coefficient are associated with the mapping relationship to quickly determine the first correction coefficient.

[0047] In the embodiment of the present invention, in order to achieve a rapid response of the joint control system of the heat pump unit when starting up, the mapping relationship is associated based on interval division. Specifically, the difference between the target outlet water temperature and the current inlet water temperature is divided into multiple temperature difference intervals, and each temperature difference interval is associated with a different first correction coefficient. Accordingly, the temperature difference interval corresponding to the difference between the target outlet water temperature and the current inlet water temperature is determined, and a search is performed based on the mapping relationship between the temperature difference interval and the first correction coefficient, so as to determine the first correction coefficient corresponding to the temperature difference interval.

[0048] In one embodiment, the mapping relationship can also be obtained through data fitting, which can be specifically in the form of a fitting curve, a fitting function, etc., that is, the correspondence between the difference between the target water outlet temperature and the current water inlet temperature and the first correction coefficient is continuous; after calculating the difference between the target water outlet temperature and the current water inlet temperature, it is brought into the corresponding mapping relationship for calculation or search to obtain the first correction coefficient.

[0049] In one embodiment, the maximum value of the first correction coefficient is 1, so as to ensure that the final correction result of the total number of units does not exceed the total number of units, thereby ensuring the reliability of the correction of the total number of units.

[0050] In one embodiment, the first correction coefficient corresponding to each temperature difference interval can be determined based on the difference between the target water outlet temperature and the current water inlet temperature and the fitting relationship with the first correction coefficient; for example, the first correction coefficient corresponding to the temperature difference in the middle of each temperature difference interval can be calculated based on the fitting relationship, and the first correction coefficient can be used as the first correction coefficient corresponding to the temperature difference interval.

[0051] In a specific embodiment, the mapping relationship between the temperature difference interval where the difference between the target water outlet temperature and the current water inlet temperature is located and the first correction coefficient can be shown in Table 1 below, where W1 represents the difference between the target water outlet temperature and the current water inlet temperature.

[0052] Table 1

[0053] Temperature range First correction factor <![CDATA[W1≤10℃]]> 0.2 <![CDATA[10℃<W1≤20℃]]> 0.4 <![CDATA[20℃<W1≤30℃]]> 0.6 <![CDATA[30℃<W1≤40℃]]> 0.8 <![CDATA[W1>40℃]]> 1.0

[0054] Step 120: Determine a second correction coefficient of the heat pump unit based on the current ambient temperature.

[0055] In the embodiment of the present invention, based on the current ambient temperature, the influence of the ambient temperature on the current demand load is determined to obtain a second correction coefficient. Specifically, when the ambient temperature is high, the temperature difference is relatively small when the heat pump unit joint control system is initially started, and the temperature fluctuation is small, so the demand load of the heat pump unit joint control system is relatively low, and the second correction coefficient is relatively small, so as to reduce the initial start-up number of the heat pump unit; when the ambient temperature is low, the temperature difference is relatively large when the heat pump unit joint control system is initially started, and the temperature fluctuation is large, so the demand load of the heat pump unit joint control system is relatively large, and the second correction coefficient is relatively large, so as to increase the initial start-up number of the heat pump unit.

[0056] In one embodiment, there is a mapping relationship between the ambient temperature and the second correction coefficient, and the ambient temperature and the second correction coefficient are associated through the mapping relationship, so as to quickly determine the second correction coefficient.

[0057] In one embodiment, the mapping relationship can be obtained through data fitting, which can be specifically in the form of a fitting curve, a fitting function, etc., that is, the corresponding relationship between the ambient temperature and the second correction coefficient is continuous; after obtaining the current ambient temperature, it is brought into the corresponding mapping relationship for calculation or search to obtain the second correction coefficient.

[0058] In one embodiment, in order to achieve a rapid response of the heat pump unit joint control system when starting up, the mapping relationship can be based on interval division for corresponding association. Specifically, the ambient temperature is divided into multiple temperature intervals, and each temperature interval is respectively associated with a different second correction coefficient. Accordingly, based on the current ambient temperature, the second correction coefficient of the heat pump unit is determined, including: determining the temperature interval corresponding to the current ambient temperature; searching based on the mapping relationship between the temperature interval and the second correction coefficient to determine the second correction coefficient corresponding to the temperature interval.

[0059] In one embodiment, the second correction coefficient corresponding to each temperature interval can be determined based on the fitting relationship between the ambient temperature and the second correction coefficient; for example, the second correction coefficient corresponding to the temperature in the middle of each temperature interval can be calculated based on the fitting relationship, and the second correction coefficient can be used as the second correction coefficient corresponding to the temperature interval.

[0060] In a specific embodiment, the mapping relationship between the ambient temperature and the second correction coefficient can be shown in Table 2 below, where T p Indicates the ambient temperature.

[0061] Table 2

[0062] Temperature range Second correction factor <![CDATA[T p ≤-15℃]]> 1.2 <![CDATA[-15℃<T p ≤-5℃]]> 1.0 <![CDATA[-5℃<T p ≤5℃]]> 0.8 <![CDATA[5℃<T p ≤15℃]]> 0.6 <![CDATA[15℃<T p ≤25℃]]> 0.5 <![CDATA[T p >25℃]]> 0.4

[0063] Step 130: Determine the initial startup quantity based on the first correction coefficient, the second correction coefficient and the total number of heat pump units.

[0064] In the embodiment of the present invention, the total number of heat pump units is corrected based on the first correction coefficient and the second correction coefficient to obtain the initial startup number.

[0065] In one embodiment, the first correction coefficient, the second correction coefficient and the total number of units are multiplied to obtain the initial start-up number. For example, the total number of units is 10, the current ambient temperature is -5°C, the current inlet water temperature is 15°C, the target outlet water temperature is 45°C, and the temperature difference between the target outlet water temperature and the current inlet water temperature is 30°C. Then, the first correction coefficient is 0.6 obtained by looking up Table 1, and the current ambient temperature is -5°C. Then, the second correction coefficient is 1.0 obtained by looking up Table 2, and the initial start-up number is 10×0.6×1.0=6.

[0066] Step 140: Control the initial number of heat pump units to start and operate.

[0067] In an embodiment of the present invention, an initial number of heat pump units are controlled to start up and run, and the operating frequency of the initially started heat pump units is set to the initial default operating frequency, and the operating frequency of the heat pump units is controlled to gradually increase to the highest frequency in the temperature zone.

[0068] In one embodiment, since the initial startup number determined based on the current water inlet temperature, the target water outlet temperature and the current ambient temperature is an estimate of the current demand load, when the heat pump units are actually controlled to operate according to the initial startup number, there will be a certain deviation between the actual water outlet temperature and the target water outlet temperature. Therefore, after the heat pump units with the initial startup number are started and operated, the start and stop and operating frequency of the heat pump units in the heat pump unit joint control system are continuously controlled to make fine adjustments after the heat pump unit joint control system is initially started to ensure that the water outlet temperature can reach the target water outlet temperature. Specifically, Figure 2 is a flow chart of controlling the start and stop and / or operating frequency of a heat pump unit in a heat pump unit joint control method according to an embodiment of the present invention, such as Figure 2 As shown, after the above step 140, the following steps are further included:

[0069] Step 210: Obtain the current outlet water temperature, and determine the current temperature difference based on the difference between the target outlet water temperature and the current outlet water temperature.

[0070] In an embodiment of the present invention, after the heat pump unit joint control system is turned on, the current outlet water temperature is obtained, and the current temperature difference is determined based on the difference between the target outlet water temperature and the current outlet water temperature. Thus, the difference between the heating load currently provided by the heat pump unit joint control system and the actually required heating load is determined based on the current temperature difference, and the subsequent operation of the heat pump unit is controlled based on the difference between the two.

[0071] Step 220: Based on the relationship between the current temperature difference and the temperature difference threshold, control the start and stop and / or operation frequency of the heat pump unit.

[0072] In the embodiment of the present invention, the control strategy of the heat pump unit is limited by the temperature difference threshold, and when the magnitude relationship between the current temperature difference and the temperature difference threshold satisfies the condition for triggering the control strategy of the heat pump unit, the corresponding control strategy is executed. Among them, the control strategy of the heat pump unit includes starting and stopping the heat pump unit, and adjusting the operating frequency of the heat pump unit.

[0073] In one embodiment, there are corresponding temperature difference thresholds for different control strategies; specifically, for controlling the shutdown of the heat pump unit, controlling the startup of the heat pump unit, controlling the frequency increase of the heat pump unit, and controlling the frequency reduction of the heat pump unit, there are corresponding temperature difference thresholds and temperature difference ranges; the temperature difference thresholds are used to limit the upper and lower temperature difference boundaries of the corresponding temperature difference range.

[0074] In one embodiment, the temperature difference threshold includes a first temperature difference threshold, a second temperature difference threshold, a third temperature difference threshold and a fourth temperature difference threshold. Among them, the first temperature difference threshold is the threshold for triggering the shutdown of the heat pump unit, the second temperature difference threshold is the threshold for triggering the startup of the heat pump unit, the third temperature difference threshold is the threshold for triggering the frequency reduction of the heat pump unit, and the fourth temperature difference threshold is the threshold for triggering the frequency increase of the heat pump unit. The first temperature difference threshold, the second temperature difference threshold, the third temperature difference threshold and the fourth temperature difference threshold have the following size relationship: the first temperature difference threshold is less than the third temperature difference threshold, the third temperature difference threshold is less than the fourth temperature difference threshold, and the fourth temperature difference threshold is less than the second temperature difference threshold.

[0075] In one embodiment, the first temperature difference threshold is a temperature difference value less than 0. When the current temperature difference is less than the first temperature difference threshold, it indicates that the current outlet water temperature is greater than the target outlet water temperature, and the temperature difference between the two is too large, which triggers the shutdown of the heat pump unit. Correspondingly, the above step 220 includes a related control strategy for controlling the shutdown of the heat pump unit, which is as follows: if the current temperature difference is less than or equal to the first temperature difference threshold, the preset number of heat pump units are controlled to shut down for the first preset duration; wherein the first preset duration is the duration of a shutdown cycle, that is, the shutdown control of the heat pump unit is carried out according to the cycle, and only one shutdown cycle is shut down each time, so as to facilitate fine-tuning of the outlet water temperature. It should be noted that after the heat pump unit joint control system controls the start-up of the heat pump unit according to the initial startup number, the control strategy for controlling the shutdown of the heat pump unit corresponding to the first temperature difference threshold can be executed to shut down the redundant heat pump units in time, so as to avoid the outlet water temperature exceeding the target outlet water temperature too much when the heat pump unit joint control system reaches stable operation, thereby ensuring the accuracy of temperature regulation.

[0076] In one embodiment, the second temperature difference threshold is a temperature difference value greater than 0. When the current temperature difference is greater than the second temperature difference threshold, it indicates that the current outlet water temperature is less than the target outlet water temperature, and the temperature difference between the two is too large, and the heat pump unit is triggered to start. Correspondingly, the above step 220 includes the relevant control strategy for controlling the start of the heat pump unit, which is as follows: if the current temperature difference is greater than or equal to the second temperature difference threshold after running for the second preset time, and the number of startups is less than the total number of units, the preset number of heat pump units are controlled to start; if the current temperature difference is greater than or equal to the second temperature difference threshold after running for the second preset time, and the number of startups is equal to the total number of units, the heat pump unit is controlled to continue to run according to the current operating state; wherein, the second preset time is the time required for the heat pump unit joint control system to start from the initial start to stable operation. It should be noted that the heat pump unit will be triggered to start only when the current number of startups is less than the total number of units. If the current number of startups is equal to the total number of units, the heat pump unit is controlled to maintain operation according to the current operating state, wherein the current operating state refers to the current number of startups and the current operating frequency of the heat pump unit.

[0077] In one embodiment, the third temperature difference threshold is a temperature difference value less than 0, and the third temperature difference threshold is greater than the first temperature difference threshold; when the current temperature difference is between the first temperature difference threshold and the third temperature difference threshold, it indicates that the current outlet water temperature is greater than the target outlet water temperature, but the difference between the two is not yet to the extent that the heat pump unit needs to be shut down, and an attempt can be made to reduce the operating frequency of the heat pump unit to adjust the current outlet water temperature back to the target outlet water temperature. Accordingly, the above step 220 includes a related control strategy for controlling the frequency reduction of the heat pump unit, as follows: if the current temperature difference is between the first temperature difference threshold and the third temperature difference threshold after running for the second preset time, the operating time of the heat pump unit is obtained, and the heat pump unit with the longest operating time is determined as the target unit; the operating frequency of the target unit is controlled to reduce the preset frequency and maintain the third preset time. Among them, the third preset time is the duration of a frequency adjustment cycle, that is, the frequency adjustment of the heat pump unit is carried out according to the cycle, and only one frequency adjustment cycle is adjusted each time, so as to facilitate fine-tuning of the outlet water temperature.

[0078] In one embodiment, the fourth temperature difference threshold is a temperature difference value greater than 0, and the fourth temperature difference threshold is less than the second temperature difference threshold. Since the operating frequency of the heat pump unit will gradually increase to the highest frequency of the temperature zone, the frequency increase of the heat pump unit will be triggered only after the heat pump unit has been frequency-reduced; if the current temperature difference is between the fourth temperature difference threshold and the second temperature difference threshold, that is, the current outlet water temperature is less than the target outlet water temperature after the heat pump unit is frequency-reduced, the current outlet water temperature can be adjusted back to the target outlet water temperature by increasing the operating frequency of the heat pump unit. Correspondingly, after the operating frequency of the above-mentioned control target unit is reduced by the preset frequency, the current outlet water temperature is updated, and the current temperature difference is updated based on the difference between the target outlet water temperature and the updated current outlet water temperature; if the updated current temperature difference is between the fourth temperature difference threshold and the second temperature difference threshold, the operating frequency of the target unit is increased by the preset frequency and maintained for the second preset duration.

[0079] In one embodiment, if the current temperature difference is between the third temperature difference threshold and the second temperature difference threshold, no control strategy for the heat pump unit will be triggered, and the heat pump unit will be controlled to continue to operate according to the current operating state. It should be noted that if the heat pump unit has been frequency-reduced before, the heat pump unit can be frequency-upgraded at this time. Therefore, after the heat pump unit is frequency-reduced, the interval corresponding to the control of the heat pump unit to maintain operation is that the current temperature difference is between the third temperature difference threshold and the fourth temperature difference threshold. That is, when the heat pump unit is operating at the highest frequency in the temperature zone, when the current temperature difference is between the third temperature difference threshold and the second temperature difference threshold, the heat pump unit maintains operation; after the heat pump unit is frequency-reduced, when the current temperature difference is between the third temperature difference threshold and the fourth temperature difference threshold, the heat pump unit maintains operation.

[0080] In a specific implementation, the first temperature difference threshold may be -3°C, the third temperature difference threshold may be -1°C, the fourth temperature difference threshold may be 1°C, and the second temperature difference threshold may be 2°C.

[0081] The heat pump unit joint control method provided by the embodiment of the present invention establishes a mapping relationship between the temperature difference interval corresponding to the difference between the target water outlet temperature and the current water inlet temperature and the first correction coefficient, and searches the mapping relationship based on the temperature difference interval corresponding to the difference between the current target water outlet temperature and the current water inlet temperature to determine the first correction coefficient, so as to ensure that the correction of the total number of units by the first correction coefficient can reflect the actual load demand for the start-up number of the heat pump units, and determine the second correction coefficient based on the current ambient temperature, so as to further correct the start-up number of the heat pump units in combination with the influence of the ambient temperature on the actual load demand, so that the initial start-up number determined based on the first correction coefficient, the second correction coefficient and the total number of units can meet the current load demand, so that the joint control system can reach a relatively stable state at the initial startup, thereby reducing the frequent startup of the heat pump units, improving the system stability, and reducing temperature fluctuations.

[0082] According to an embodiment of the present invention, on the other hand, a heat pump unit joint control system is provided, comprising a plurality of heat pump units and a controller; the controller is used to execute the heat pump unit joint control method as described in any of the above embodiments.

[0083] In one embodiment, in a heat pump unit joint control system, multiple heat pump units are respectively connected to a controller for communication, and the controller uniformly controls and coordinates the multiple heat pump units, thereby forming a master-slave-free control system, thereby avoiding the failure of the host machine causing all heat pump units in the heat pump unit joint control system to be unusable, thereby improving system reliability.

[0084] In the specific contents of the above-mentioned specific implementation methods, the various technical features can be combined in any non-contradictory manner. In order to make the description concise, not all possible combinations of the above-mentioned technical features are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0085] The specific contents of the above specific implementations only express several implementations of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention.

Claims

1. A heat pump unit joint control method, characterized in that: Applied to a heat pump unit joint control system, the heat pump unit joint control system includes multiple heat pump units; the method includes: In response to the heat pump joint control system being started, based on the temperature difference interval corresponding to the difference between the target water outlet temperature and the current water inlet temperature, a mapping relationship between the temperature difference interval and the first correction coefficient is searched to determine the first correction coefficient of the heat pump unit; Determining a second correction coefficient of the heat pump unit based on the current ambient temperature; Determining an initial startup quantity based on the first correction coefficient, the second correction coefficient, and the total number of units of the heat pump unit; Control the initial number of heat pump units to start and run.

2. The method according to claim 1, characterized in that The step of determining the second correction coefficient of the heat pump unit based on the current ambient temperature includes: Determine a temperature range corresponding to the current ambient temperature; A search is performed based on a mapping relationship between the temperature interval and the second correction coefficient to determine the second correction coefficient corresponding to the temperature interval.

3. The method according to claim 1, characterized in that The determining the initial startup quantity based on the first correction coefficient, the second correction coefficient and the total number of the heat pump units includes: The first correction coefficient, the second correction coefficient and the total number of units are multiplied to obtain the initial opening quantity.

4. The method according to any one of claims 1 to 3, characterized in that: After the heat pump units of the initial startup quantity are controlled to be started and run, the method further includes: Acquire the current outlet water temperature, and determine the current temperature difference based on the difference between the target outlet water temperature and the current outlet water temperature; Based on the magnitude relationship between the current temperature difference and the temperature difference threshold, the start and stop and / or operating frequency of the heat pump unit are controlled.

5. The method according to claim 4, characterized in that The temperature difference threshold comprises a first temperature difference threshold; and the control of the start and stop and / or operation frequency of the heat pump unit based on the magnitude relationship between the current temperature difference and the temperature difference threshold comprises: If the current temperature difference is less than or equal to the first temperature difference threshold, a preset number of heat pump units are controlled to shut down for a first preset time period.

6. The method according to claim 4, characterized in that The temperature difference threshold includes a second temperature difference threshold and a third temperature difference threshold, the second temperature difference threshold is greater than the first temperature difference threshold, and the second temperature difference threshold is greater than the third temperature difference threshold; the control of the start and stop and / or operation frequency of the heat pump unit based on the magnitude relationship between the current temperature difference and the temperature difference threshold includes: If the current temperature difference is between the third temperature difference threshold and the second temperature difference threshold, the heat pump unit is controlled to continue operating according to the current operating state.

7. The method according to claim 4, characterized in that The temperature difference threshold includes a second temperature difference threshold, and the second temperature difference threshold is greater than the first temperature difference threshold; and controlling the start and stop and / or operation frequency of the heat pump unit based on the magnitude relationship between the current temperature difference and the temperature difference threshold includes: If the current temperature difference is greater than or equal to the second temperature difference threshold after running for the second preset time, and the number of units started is less than the total number of units, then a preset number of heat pump units are controlled to start; If the current temperature difference is greater than or equal to the second temperature difference threshold after running for the second preset time, and the number of startup units is equal to the total number of units, the heat pump unit is controlled to continue running according to the current operating state.

8. The method according to claim 4, characterized in that The temperature difference threshold includes a first temperature difference threshold and a third temperature difference threshold, the third temperature difference threshold is greater than the first temperature difference threshold, and the third temperature difference threshold is less than the second temperature difference threshold; the control of the start and stop and / or operation frequency of the heat pump unit based on the magnitude relationship between the current temperature difference and the temperature difference threshold includes: If the current temperature difference is between the first temperature difference threshold and the third temperature difference threshold after running for the second preset time, the running time of the heat pump unit is obtained, and the heat pump unit with the longest running time is determined as the target unit; The operating frequency of the target unit is controlled to decrease by a preset frequency and maintained for a third preset time period.

9. The method according to claim 8, characterized in that The temperature difference threshold further includes a second temperature difference threshold and a fourth temperature difference threshold, the second temperature difference threshold is greater than the fourth temperature difference threshold, and the fourth temperature difference threshold is greater than the third temperature difference threshold; after the operating frequency of the target unit is controlled to be reduced by a preset frequency, the method further includes: updating the current outlet water temperature, and updating the current temperature difference based on the difference between the target outlet water temperature and the updated current outlet water temperature; If the updated current temperature difference is between the fourth temperature difference threshold and the second temperature difference threshold, the operating frequency of the target unit is increased by the preset frequency and maintained for the third preset time period.

10. A heat pump unit joint control system, characterized in that: It comprises a plurality of heat pump units and a controller; the controller is used to execute the heat pump unit joint control method as described in any one of claims 1-9.

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