Method for controlling loading and unloading of compressors among multiple modules of air source heat pump water heater

Abstract

The invention relates to a loading and unloading control technology for multi-unit combined operation, and discloses a method for controlling loading and unloading of compressors among multiple modules of an air source heat pump water heater, which realizes intelligent, efficient and balanced loading and unloading control of the compressors among the multiple modules. The loading and unloading areas are divided by presetting adjustable temperature difference parameters, the frequency variation of the compressor is calculated based on the difference value between the set water temperature and the actual water temperature and the water temperature change rate, differential loading and unloading adjustment is conducted on the compressor in different load states in combination with the operation state of each module, it is preferentially guaranteed that the compressor operates at the optimal frequency, and the working efficiency is improved. Advanced loading of a new module and preferential unloading of a high-frequency module are achieved, and finally intelligent, efficient and balanced loading and unloading control over compressors among multiple modules is achieved.

Description

Technical Field

[0001] The present invention relates to a loading and unloading control technology for the joint operation of multiple units, and in particular to a method for controlling the loading and unloading of compressors between multiple modules of an air source heat pump water heater. Background Art

[0002] Air-source heat pump water heaters, with their energy-saving and environmentally friendly advantages, have been widely used in scenarios requiring large quantities of domestic hot water, such as shopping malls, hotels, residential communities, and schools. Because hot water load demands vary across different scenarios, manufacturers typically produce units with varying heating capacity ranges. In practice, multiple independent units of the same or different capacity ranges must be combined and operated based on real-time load to meet user hot water needs. This involves the issue of load and unload control between multiple units, and the rationality of the control logic directly impacts the unit's operating efficiency and stability.

[0003] Currently, the traditional multi-unit loading and unloading control method uses a fixed temperature control cycle, and loads or unloads a unit in each temperature control cycle based on the difference between the set temperature and the actual water temperature. This control method has the following significant drawbacks: (1) Loading and unloading lag: When the actual water temperature reaches the set temperature, there is a lag in the unloading action, which can easily cause the water temperature to exceed the user's set value; when the initial water temperature is low, loading is not timely, and the compressors need to be started one by one and each compressor gradually increases from the lowest frequency to the highest frequency, causing the water temperature to rise slowly and unable to quickly meet the hot water demand.

[0004] (2) Unbalanced unit operation: Due to the limitation of control logic, the unit loaded first may be in a high-frequency operation state for a long time, and the new unit will not be added until the existing unit reaches the highest frequency; there is a lack of priority adjustment for the high-load unit during unloading, resulting in uneven distribution of operating loads among the units, and some units are in non-optimal operating conditions for a long time.

[0005] (3) Low operating efficiency: Since the loading and unloading strategies are not optimized for the optimal performance point of the compressor, most compressors cannot operate stably in the high-efficiency range, but frequently fluctuate at non-optimal frequencies, resulting in high overall unit energy consumption and low energy utilization.

[0006] Therefore, there is an urgent need for a loading and unloading control method that can adapt to multi-unit combination scenarios and achieve precise adjustment to improve the overall operating performance of air source heat pump water heaters. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a method for controlling loading and unloading of compressors among multiple modules of an air source heat pump water heater, so as to realize intelligent, efficient and balanced loading and unloading control of compressors among multiple modules.

[0008] The technical solution adopted by the present invention to solve the above technical problems is: A method for controlling the loading and unloading of compressors between multiple modules of an air source heat pump water heater is provided for an air source heat pump water heater operating in a multi-module combination. The control method comprises the following steps: S1. Preset adjustable temperature difference parameters. Based on the preset adjustable temperature difference parameters, the set water tank temperature, and the actual water tank temperature, the emergency stop zone, unloading zone, holding zone, and loading zone are divided; S2. When you first start the machine, perform the corresponding operation according to the actual water tank temperature range: If it is in the emergency stop area or unloading area, it will stop; if it is in the holding area, it will maintain the current state; if it is in the loading area, it will enter the loading control logic; S3. In each calculation cycle, based on the difference A between the set water tank temperature and the actual water tank temperature, the difference B between the current actual water tank temperature and the actual water tank temperature in the previous cycle, calculate the compressor frequency change Δrps; S4. Based on Δrps, the number of currently running modules, the number of startable modules, the number of modules in each load state, and the cumulative frequency change ∑Δrps, adjust the compressor frequency of each module or perform loading and unloading operations.

[0009] Furthermore, in step S1, the method of dividing the emergency stop area, the unloading area, the holding area, and the loading area according to the preset adjustable temperature difference parameter, the set water tank temperature, and the actual water tank temperature includes: Emergency stop area: actual water tank temperature ≥ set water tank temperature + T 调节 Or the actual water tank temperature is ≥61℃; Unloading area: set water tank temperature + 1.0 < actual water tank temperature < set water tank temperature + T 调节 ; Holding area: set water tank temperature – T 调节 / 2≤actual water tank temperature≤set water tank temperature+1.0; Loading area: actual water tank temperature < set water temperature – T 调节 / 2 and the actual water tank temperature is ≤50℃; Among them, T 调节 It is a preset adjustable temperature difference parameter with a value range of 1~10℃.

[0010] Furthermore, in step S2, if it is in the loading area, the number of modules put into the system for the first time is MK. 首次投入数 = (set water tank temperature - actual water tank temperature) / 10) × MK 总模块数 , the calculation result is rounded down, and 1≤MK 首次投入数 <MK 可启动数 , among which, MK 总模块数 is the total number of modules in the system; MK 可启动数 The number of all modules that can be started normally in the system.

[0011] Furthermore, in step S3, the calculation period is 10s to 60s.

[0012] Furthermore, in step S3, the calculation method of the compressor frequency change Δrps includes: When A>0: If B>0, then Δrps=0.5A-8B; if B=0, then Δrps=0.2A; if B<0, then Δrps=0.5A-5B; When A=0: If B>0, then Δrps=-15B; if B=0, then Δrps=0; if B<0, then Δrps=-5B; When A<0: If B>0, then Δrps=2A-15B; if B=0, then Δrps=2A; if B<0, then Δrps=2A-5B.

[0013] Furthermore, in step S4, the load state includes: high load, medium load and low load; A high-load module refers to a module with a compressor operating frequency ≥ 80% × RPSmax; The medium load module is a module where 43%×RPSmax<compressor operating frequency<80%×RPSmax; The low-load module is a module where the compressor operating frequency is less than 43%×RPSmax; RPSmax is the maximum frequency at which the module's compressor can operate.

[0014] Furthermore, in step S4, the cumulative frequency variation ΣΔrps refers to the accumulated value of the compressor frequency variation Δrps in each cycle.

[0015] Furthermore, in step S4, based on Δrps, the number of currently running modules, the number of startable modules, the number of modules in each load state, and the cumulative frequency change ∑Δrps, the method for adjusting the compressor frequency of each module or performing loading and unloading operations includes: When Δrps ≥ 0, the compressor frequencies in modules with different load states are adjusted based on the comparison between the number of currently running modules and the number of startable modules, and the existence of modules in medium and low load states, and new modules are loaded when the conditions are met; When Δrps is less than 0, the compressor frequency of different load states is adjusted based on the existence of modules in high load state, the quantitative relationship between modules in medium load state and low load state, and the size of the cumulative frequency change, and the module is unloaded when the conditions are met.

[0016] Furthermore, when Δrps ≥ 0, the compressor frequencies of modules in different load states are adjusted based on the comparison between the number of currently running modules and the number of startable modules, and the presence of modules in medium and low load states, and new modules are loaded when conditions are met, including: (1) When Δrps ≥ 0, and MK 运行数 <MK 可启动数 And (MK 中负荷数 +MK 低负荷数 )>0: Cmpr 高负荷 Compressor frequency rps=rps_old; Cmpr 中负荷 Compressor frequency rps=rps_old+Δrps1, Δrps1=Δrps × MK 总模块数 / (MK 中负荷数 + MK 低负荷数 ), and Δrps1≤5rps; Cmpr 低负荷 Compressor frequency rps=rps_old+Δrps1, Δrps1=Δrps × MK 总模块数 / (MK 中负荷数 + MK 低负荷数 ), and Δrps1≤5rps; Among them, MK 运行数 The number of currently running modules; MK 可启动数 The number of bootable modules; MK 中负荷数 The number of modules in medium load state; MK 低负荷数 The number of modules in low load state; Cmpr 高负荷 It is a high load state module; Cmpr 中负荷 For the medium load state module; Cmpr 低负荷 It is a low load state module; rps is the frequency of the compressor in the next cycle; rps_old is the frequency of the compressor in the current cycle; MK 总模块数 is the total number of modules in the system; (2) When Δrps ≥ 0, and MK 运行数 <MK 可启动数 , and (MK 中负荷数 +MK 低负荷数 )=0, And ∑Δrps×MK 总模块数 <=5: Cmpr 高负荷 Compressor frequency rps=rps_old; (3) When Δrps ≥ 0, and MK 运行数 <MK可启动数 And (MK 中负荷数 +MK 低负荷数 )=0, And ∑Δrps×MK 总模块数 >5 o'clock: Cmpr 高负荷 Compressor frequency rps=rps_old; Cmpr 中负荷 Compressor frequency rps=rps+Δrps; Cmpr 低负荷 Compressor frequency rps=rps+Δrps; When a new module is loaded, set ∑Δrps = 0 and start accumulating again from the next cycle; (4) When Δrps ≥ 0, and MK 运行数 = MK 可启动数 , and (MK 中负荷数 +MK 低负荷数 )>0: Cmpr 高负荷 Compressor frequency rps=rps_old; Cmpr 中负荷 Compressor frequency rps=rps_old+Δrps1, Δrps1=Δrps × MK 总模块数 / (MK 中负荷数 + MK 低负荷数 ), and Δrps1<=5rps; Cmpr 低负荷 Compressor frequency rps=rps_old+Δrps1, Δrps1=Δrps × MK 总模块数 / (MK 中负荷数 + MK 低负荷数 ), and Δrps1<=5rps; (5) When Δrps ≥ 0, and MK 运行数 = MK 可启动数 , and (MK 中负荷数 +MK 低负荷数 )=0: Cmpr 高负荷 The compressor frequency rps=rps_old+Δrps, and Δrps<=3rps.

[0017] Furthermore, when Δrps is less than 0, the compressor frequencies of different load states are adjusted based on the presence of modules in high load state, the relationship between the number of modules in medium load state and low load state, and the magnitude of the cumulative frequency change, and the modules are unloaded when the conditions are met, including: (1) When Δrps < 0, and MK 高负荷数 >0, and (MK 中负荷数 +MK 低负荷数 )>0: Cmpr 高负荷 Compressor frequency rps=rps_old+Δrps1, Δrps1=Δrps × MK 总模块数 / MK 高负荷数 , and Δrps1<=10rps; Cmpr 中负荷 Compressor frequency rps=rps_old; Cmpr 低负荷 Compressor frequency rps=rps_old; (2) When Δrps<0, and MK 高负荷数 >0, and (MK 中负荷数 +MK 低负荷数 )=0: Cmpr 高负荷 Compressor frequency rps=rps_old+Δrps, and Δrps<=10rps; (3) When Δrps<0, and MK 高负荷数 =0, and MK 低负荷数 =0 and MK 中负荷数 >0 hours: Cmpr 中负荷 Compressor frequency rps=rps_old+Δrps1, Δrps1=Δrps ×MK 总模块数 / MK 中负荷数 , and Δrps1<=10rps; (4) When Δrps<0, and MK 高负荷数 =0 and MK 低负荷数 >0 and MK 中负荷数 >0 hours: Cmpr 中负荷 Compressor frequency rps=rps_old+Δrps1, Δrps1=Δrps ×MK 总模块数 / MK 低负荷数 , and Δrps1<=10rps; Cmpr 低负荷 Compressor frequency rps=rps_old; (5) When Δrps<0, and MK 高负荷数 =0, and MK 低负荷数 >0 and MK 中负荷数 =0 and ∑Δrps>=-10: Cmpr 低负荷 Compressor frequency rps=rps_old; (6) When Δrps<0, and MK 高负荷数 =0 and MK 低负荷数 >0 and MK 中负荷数 =0 and ∑Δrps<-10: Unload a module, set ∑Δrps = 0, and start accumulating again from the next cycle.

[0018] Furthermore, when loading a new module, priority is given to loading the module with no faults and the shortest running time in the system; when unloading a module, priority is given to unloading the module with no faults and the longest running time in the system.

[0019] The beneficial effects of the present invention are: (1) High degree of intelligent control: According to the different water temperature differences, the number of units to be loaded and unloaded and the loading and unloading range of each unit are dynamically adjusted. The greater the temperature difference, the more units will be put into use and the greater the loading and unloading range; the smaller the temperature difference, the fewer units will be put into use and the smaller the loading and unloading range, thus achieving precise control on demand.

[0020] (2) Achieve balanced operation of the compressor: New modules are added in advance to avoid having to wait until the previously loaded units have reached their highest frequency before adding new modules. When unloading, the frequency of high-frequency compressors is lowered first, and then the decision on whether to unload the module is made based on the cumulative frequency change, ensuring balanced load distribution among the compressors and reducing the situation where some units operate at high or low load for a long time.

[0021] (3) Improve operational efficiency: The control logic prioritizes ensuring that each compressor operates at the optimal frequency, and then gradually loads it to the highest frequency, reducing the operating time of the compressor at non-optimal performance points. At the same time, through differentiated loading and unloading strategies, each compressor can be kept in the efficient operating range for a longer period of time, thereby improving the energy utilization efficiency of the entire unit.

[0022] (4) Sensitive and fast response: By pre-setting adjustable temperature difference parameters to divide the loading and unloading areas, the frequency change is calculated in real time according to the calculation cycle, and branch control logic is designed for different conditions of multi-module operation. It can be adjusted in time according to the water temperature difference and change trend, avoiding the loading and unloading lag problem in traditional control and achieving rapid response to water temperature changes. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a flow chart of a method for controlling loading and unloading compressors between multiple modules of an air source heat pump water heater in an embodiment of the present invention. DETAILED DESCRIPTION

[0024] The present invention aims to provide a method for controlling loading and unloading of compressors between multiple modules of an air source heat pump water heater, thereby realizing intelligent, efficient, and balanced loading and unloading control of compressors between multiple modules. The core idea is to divide the loading and unloading areas of an air source heat pump water heater with multiple units in combination by presetting adjustable temperature difference parameters, calculate the frequency change of the compressor based on the difference between the set water temperature and the actual water temperature and the water temperature change rate, and perform differentiated loading and unloading adjustments on compressors in different load states in combination with the operating status of each module, giving priority to ensuring that the compressor operates at the optimal frequency, realizing early loading of new modules and priority unloading of high-frequency modules, and ultimately achieving intelligent, efficient, and balanced loading and unloading control of compressors between multiple modules.

[0025] Example: The implementation process of the method for controlling the loading and unloading of compressors between multiple modules of an air source heat pump water heater provided in this embodiment is shown in FIG. Figure 1 , which includes the following implementation steps: S1. Divide the loading and unloading areas: In this step, the adjustable temperature difference parameters are first preset, and then the emergency stop area, unloading area, holding area, and loading area are divided according to the preset adjustable temperature difference parameters, the set water tank temperature, and the actual water tank temperature.

[0026] In an exemplary embodiment, the temperature difference parameter T can be adjusted 调节 The value range is 1~10℃, and the initial default value is 5℃; the above four intervals are specifically divided as follows: Emergency stop area: actual water tank temperature ≥ set water tank temperature + T 调节 Or the actual water tank temperature is ≥61℃; Unloading area: set water tank temperature + 1.0 < actual water tank temperature < set water tank temperature + T 调节 ; Holding area: set water tank temperature – T 调节 / 2≤actual water tank temperature≤set water tank temperature+1.0; Loading area: actual water tank temperature < set water temperature – T 调节 / 2 and the actual water tank temperature is ≤50℃.

[0027] S2. When starting up the machine for the first time, perform the following operations based on the actual water tank temperature: In this step, when the machine is turned on for the first time, the actual water tank temperature is compared with the four intervals divided above. If it is currently in the emergency stop area or unloading area, it means that the actual water tank temperature is already higher than the set temperature and needs to be shut down immediately; if it is currently in the holding area, it means that the actual water tank temperature is close to the set water tank temperature, and it is necessary to maintain the current module state to allow the temperature to continue to rise; if it is currently in the loading area, it means that the module needs to be loaded to cause the water temperature to rise as quickly as possible.

[0028] S3. Calculate the compressor frequency change Δrps: In this step, in each calculation cycle, the compressor frequency change Δrps is calculated based on the difference A between the set water tank temperature and the actual water tank temperature and the difference B between the current actual water tank temperature and the actual water tank temperature in the previous cycle.

[0029] In an exemplary embodiment, the calculation cycle ranges from 10s to 60s, preferably 30s. The compressor frequency change, Δrps, is calculated using a preset formula based on the difference A between the set and actual water tank temperatures, and the difference B between the current actual water tank temperature and the actual water tank temperature in the previous calculation cycle. It directly reflects the degree of deviation between the current water temperature and the target temperature, as well as the water temperature trend, and determines the amount by which the compressor frequency needs to be increased or decreased in the next cycle. When Δrps ≥ 0, it indicates a need to increase the compressor frequency to increase heating capacity (a loading trend); when Δrps < 0, it indicates a need to decrease the compressor frequency to reduce heating capacity (an unloading trend). The magnitude of this value reflects the urgency of load adjustment: larger temperature differences and more pronounced trends increase the absolute value of Δrps.

[0030] A schematic calculation table of Δrps is shown in Table 1: Table 1 Δrps calculation table

[0031] S4. Based on Δrps and the module operating status, adjust the compressor frequency or perform loading and unloading operations: In this step, based on Δrps, the number of currently running modules, the number of startable modules, the number of modules in each load state, and the cumulative frequency change ΣΔrps, the compressor frequency of each module is adjusted or loading and unloading operations are performed.

[0032] In an exemplary embodiment, the load state is divided into three states: high load, medium load and low load, wherein the high load module refers to a module with a compressor operating frequency ≥80%×RPSmax; the medium load module refers to a module with a compressor operating frequency of 43%×RPSmax<80%×RPSmax; and the low load module refers to a module with a compressor operating frequency of <43%×RPSmax; wherein RPSmax is the maximum frequency at which the compressor of the module can operate.

[0033] The cumulative frequency change, ∑Δrps, is the sum of the Δrps values ​​from each calculation cycle, reflecting the cumulative degree of load adjustment demand over time. It is used to determine whether significant load adjustments require adding or removing modules, rather than relying solely on frequency changes of individual compressors. When the cumulative value reaches a certain threshold, frequency adjustment of a single compressor is insufficient to meet the load demand, and the number of modules must be increased or decreased to balance the load. This prevents the compressor from operating in extreme frequency ranges for extended periods, while ensuring the rationality and stability of loading and unloading operations. After adding or removing modules, ∑Δrps is reset and accumulation restarts to adapt to the new operating conditions.

[0034] To facilitate the description of the control logic for adjusting the compressor frequency or performing loading and unloading operations in this step, the parameter definitions appearing in the control logic are shown in Table 2: Table 2 Parameter definition table

[0035] Based on the above parameter definitions, an exemplary control logic is as follows: (1) When Δrps ≥ 0, and MK 运行数 <MK 可启动数 And (MK 中负荷数 +MK 低负荷数 )>0: Cmpr 高负荷 Compressor frequency rps=rps_old; Cmpr 中负荷 Compressor frequency rps=rps_old+Δrps1, Δrps1=Δrps ×MK 总模块数 / (MK 中负荷数 + MK 低负荷数 ), and Δrps1≤5rps; Cmpr 低负荷 Compressor frequency rps=rps_old+Δrps1, Δrps1=Δrps × MK 总模块数 / (MK 中负荷数 + MK 低负荷数 ), and Δrps1≤5rps; According to this logic, when the load needs to be increased (Δrps ≥ 0) and there are still startable modules, the frequency of low-load and medium-load compressors is increased first to prevent the high-load compressors from running at a higher frequency and balance the loads of each module. At the same time, the single frequency increase is limited (≤ 5rps) to prevent excessive frequency fluctuations from affecting system stability, allowing low-load modules to gradually take on more loads and improve overall operating efficiency.

[0036] (2) When Δrps ≥ 0, and MK运行数 <MK 可启动数 , and (MK 中负荷数 +MK 低负荷数 )=0, And ∑Δrps×MK 总模块数 <=5: Cmpr 高负荷 Compressor frequency rps=rps_old; According to this logic, when the load needs to be increased and there are still startable modules, if all operating modules are at high load (there are no medium load and low load modules), but the cumulative load demand increment is small, the load demand can be met without adjusting the frequency. Therefore, the frequency of each compressor in the next cycle remains unchanged at the current frequency, avoiding unnecessary frequency changes, reducing energy consumption and equipment losses, and maintaining system stability.

[0037] (3) When Δrps ≥ 0, and MK 运行数 <MK 可启动数 And (MK 中负荷数 +MK 低负荷数 )=0, And ∑Δrps×MK 总模块数 >5 o'clock: Cmpr 高负荷 Compressor frequency rps=rps_old; Cmpr 中负荷 Compressor frequency rps=rps+Δrps; Cmpr 低负荷 Compressor frequency rps=rps+Δrps; When a new module is loaded, set ∑Δrps = 0 and start accumulating again from the next cycle; According to this logic, when the load needs to be increased and there are still startable modules, if all operating modules are at high load (there are no medium load and low load modules), when the cumulative load demand increase is large, the load is shared by loading new modules in advance to avoid long-term high-frequency operation of existing high-load modules resulting in efficiency degradation or overload; after loading the new modules, ∑Δrps is cleared and the load demand is accumulated again to ensure a more balanced load distribution and improve the overall heating capacity and response speed of the system.

[0038] (4) When Δrps ≥ 0, and MK 运行数 = MK 可启动数 , and (MK 中负荷数 +MK 低负荷数 )>0: Cmpr 高负荷 Compressor frequency rps=rps_old; Cmpr 中负荷Compressor frequency rps=rps_old+Δrps1, Δrps1=Δrps× MK 总模块数 / (MK 中负荷数 + MK 低负荷数 ), and Δrps1<=5rps; Cmpr 低负荷 Compressor frequency rps=rps_old+Δrps1, Δrps1=Δrps× MK 总模块数 / (MK 中负荷数 + MK 低负荷数 ), and Δrps1<=5rps; According to this logic, when the load needs to be increased, when all startable modules are already running (new modules cannot be loaded) and there are medium-load / low-load modules, the load is shared by increasing the frequency of these low- and medium-load modules to avoid further high-frequency operation of high-load modules, thereby balancing the load of each module and ensuring that each compressor operates in the high-efficiency range as much as possible, thereby improving energy utilization.

[0039] (5) When Δrps ≥ 0, and MK 运行数 = MK 可启动数 , and (MK 中负荷数 +MK 低负荷数 )=0: Cmpr 高负荷 The compressor frequency rps=rps_old+Δrps, and Δrps<=3rps.

[0040] According to this logic, when the load needs to be increased, when all startable modules are already running and all modules are in a high-load state, the frequency of the high-load compressor can only be slightly increased (≤3rps) to avoid the frequency being too high and exceeding the optimal performance point, reducing energy consumption and equipment wear, and taking into account operating efficiency and equipment life while meeting load requirements.

[0041] (6) When Δrps<0, and MK 高负荷数 >0, and (MK 中负荷数 +MK 低负荷数 )>0: Cmpr 高负荷 Compressor frequency rps=rps_old+Δrps1, Δrps1=Δrps× MK 总模块数 / MK 高负荷数 , and Δrps1<=10rps; Cmpr 中负荷 Compressor frequency rps=rps_old; Cmpr 低负荷Compressor frequency rps=rps_old; According to this logic, when the load needs to be reduced and there are modules in a high-load state as well as modules in a medium- and low-load state, the frequency of the high-load compressor is reduced first to avoid its long-term high-frequency operation leading to inefficiency. At the same time, the medium- and low-load modules are kept stable to balance the module load and allow the high-load module to return to a more efficient frequency range.

[0042] (7) When Δrps<0, and MK 高负荷数 >0, and (MK 中负荷数 +MK 低负荷数 )=0: Cmpr 高负荷 Compressor frequency rps=rps_old+Δrps, and Δrps<=10rps; According to this logic, when the load needs to be reduced and all operating modules are under high load, the frequency is directly reduced to reduce the total load, and the single reduction is limited to 10rps to avoid system fluctuations caused by a sudden drop in frequency, ensure a smooth load reduction, and allow high-load modules to quickly return to the efficient operating range.

[0043] (8) When Δrps < 0, and MK 高负荷数 =0, and MK 低负荷数 =0 and MK 中负荷数 >0 hours: Cmpr 中负荷 Compressor frequency rps=rps_old+Δrps1, Δrps1=Δrps ×MK 总模块数 / MK 中负荷数 , and Δrps1<=10rps; According to this logic, when the load needs to be reduced and there are no high-load and low-load modules, the total load is reduced only by reducing the frequency of the medium-load modules, and the reduction is distributed proportionally based on the number of loads to ensure that the load of each medium-load module is reduced evenly, avoid excessive load fluctuations in some modules, and maintain system stability.

[0044] (9) When Δrps < 0, and MK 高负荷数 =0 and MK 低负荷数 >0 and MK 中负荷数 >0 hours: Cmpr 中负荷 Compressor frequency rps=rps_old+Δrps1, Δrps1=Δrps× MK 总模块数 / MK 低负荷数 , and Δrps1<=10rps; Cmpr 低负荷Compressor frequency rps=rps_old; According to this logic, when the load needs to be reduced and there are no high-load modules but medium and low-load modules, the frequency of the medium-load modules should be reduced first to reduce the total load, while keeping the low-load modules stable to prevent their frequencies from further decreasing to the inefficient range, ensuring that the low-load modules can still operate at a relatively reasonable frequency, taking into account both the load reduction demand and the overall operating efficiency.

[0045] (10) When Δrps < 0, and MK 高负荷数 =0, and MK 低负荷数 >0 and MK 中负荷数 =0 and ∑Δrps>=-10: Cmpr 低负荷 Compressor frequency rps=rps_old; According to this logic, when the load needs to be reduced and there are only low-load modules but no high-load modules or medium-load modules, and the cumulative load reduction demand is small (∑Δrps≥-10), the load demand can be met without adjusting the frequency, avoiding further reduction in the frequency of the low-load modules, resulting in reduced efficiency or frequent starting and stopping, and maintaining stable system operation.

[0046] (11) When Δrps < 0, and MK 高负荷数 =0 and MK 低负荷数 >0 and MK 中负荷数 =0 and ∑Δrps<-10: Unload a module, set ∑Δrps = 0, and start accumulating again from the next cycle.

[0047] According to this logic, when the load needs to be reduced and there are only low-load modules but no high-load or medium-load modules, and when the cumulative load reduction demand is large (∑Δrps<-10), the total load is reduced by unloading one module to avoid low efficiency caused by the low-load module frequency being too low. At the same time, ∑Δrps is cleared and re-accumulated to ensure more accurate load adjustment, balance the operating time of each module, and extend the life of the equipment.

[0048] During the implementation of the above embodiment, for the detection of the actual water tank temperature, the water tank temperature of the main unit (unit 1) is used as the basis for water tank temperature control by default. When the water tank temperature sensor of the main unit (unit 1) fails, the following processing is performed: after the unit is powered on, if the water tank temperature sensor is detected to be open or short-circuited, a water tank temperature sensor failure is reported. If the return water temperature of the main unit is normal, it is temporarily used as the water tank temperature sensor to continue starting or operating. Otherwise, the return water temperature sensor of unit 2 is temporarily used as the water tank temperature, and so on. If the return water sensors of all units are broken, the system is shut down. When it is detected that the water tank temperature sensor failure has been eliminated, the normal function of the water tank temperature sensor is restored.

[0049] When the module is loaded for the first time, the number of modules put into operation for the first time is MK. 首次投入数 = (set water tank temperature - actual water tank temperature) / 10) × MK 总模块数 , the calculation result is rounded down, and 1≤MK 首次投入数 <MK 可启动数 , among which, MK 总模块数 is the total number of modules in the system; MK 可启动数 The number of all modules that can be started normally in the system.

[0050] During the execution of the loading control logic, when a module needs to be loaded, priority is given to loading the unit in the system that is free of faults and has the shortest running time; when a module needs to be unloaded, priority is given to unloading the unit in the system that is free of faults and has the longest running time, and the principle of first in, first out and last in, last out is adopted.

[0051] Although the embodiments of the present invention have been described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present invention, all without departing from the scope of protection of the present invention.

Claims

1. A method for controlling the loading and unloading of compressors between multiple modules of an air source heat pump water heater, which is used for an air source heat pump water heater with multiple modules in combined operation, characterized in that: The control method comprises the following steps: S1. Preset adjustable temperature difference parameters, and divide the emergency stop area, unloading area, holding area, and loading area according to the preset adjustable temperature difference parameters, the set water tank temperature, and the actual water tank temperature; S2. When starting up the machine for the first time, perform the corresponding operation according to the actual water tank temperature range: If it is in the emergency stop area or unloading area, it will stop; if it is in the holding area, it will maintain the current state; if it is in the loading area, it will enter the loading control logic; S3. In each calculation cycle, based on the difference A between the set water tank temperature and the actual water tank temperature, the difference B between the current actual water tank temperature and the actual water tank temperature in the previous cycle, calculate the compressor frequency change Δrps; S4. Based on Δrps, the number of currently running modules, the number of startable modules, the number of modules in each load state, and the cumulative frequency change ∑Δrps, adjust the compressor frequency of each module or perform loading and unloading operations.

2. The method for controlling loading and unloading of compressors between multiple modules of an air source heat pump water heater according to claim 1, characterized in that: In step S1, the method of dividing the emergency stop area, the unloading area, the holding area, and the loading area according to the preset adjustable temperature difference parameter, the set water tank temperature, and the actual water tank temperature includes: Emergency stop area: actual water tank temperature ≥ set water tank temperature + T 调节 Or the actual water tank temperature is ≥61℃; Unloading area: set water tank temperature + 1.0 < actual water tank temperature < set water tank temperature + T 调节 ; Holding area: set water tank temperature – T 调节 / 2≤actual water tank temperature≤set water tank temperature+1.0; Loading area: actual water tank temperature < set water temperature – T 调节 / 2 and the actual water tank temperature is ≤50℃; Among them, T 调节 It is a preset adjustable temperature difference parameter with a value range of 1~10℃.

3. The method for controlling the loading and unloading of compressors between multiple modules of an air source heat pump water heater according to claim 1, wherein: In step S2, if it is in the loading area, the number of modules put into the system for the first time is MK. 首次投入数 = (set water tank temperature - actual water tank temperature) / 10) × MK 总模块数 , the calculation result is rounded down, and 1≤MK 首次投入数 < MK 可启动数 , among which, MK 总模块数 is the total number of modules in the system; MK 可启动数 The number of all modules that can be started normally in the system.

4. The method for controlling loading and unloading of compressors between multiple modules of an air source heat pump water heater according to claim 1, characterized in that: In step S3, the calculation period is 10s to 60s; The calculation method of the compressor frequency change Δrps includes: When A>0: If B>0, then Δrps=0.5A-8B; if B=0, then Δrps=0.2A; if B<0, then Δrps=0.5A-5B; When A=0: If B>0, then Δrps=-15B; if B=0, then Δrps=0; if B<0, then Δrps=-5B; When A<0: If B>0, then Δrps=2A-15B; if B=0, then Δrps=2A; if B<0, then Δrps=2A-5B.

5. The method for controlling loading and unloading of compressors between multiple modules of an air source heat pump water heater according to claim 1, wherein: In step S4, the load state includes: high load, medium load and low load; A high-load module refers to a module with a compressor operating frequency ≥ 80% × RPSmax; The medium load module is a module where 43%×RPSmax<compressor operating frequency<80%×RPSmax; The low-load module is a module where the compressor operating frequency is less than 43%×RPSmax; RPSmax is the maximum frequency at which the module's compressor can operate.

6. The method for controlling loading and unloading compressors between multiple modules of an air source heat pump water heater according to claim 1, wherein: In step S4 , the cumulative frequency variation ΣΔrps refers to the accumulated value of the compressor frequency variation Δrps in each cycle.

7. The method for controlling loading and unloading of compressors between multiple modules of an air source heat pump water heater according to claim 5, characterized in that: In step S4, based on Δrps, the number of currently running modules, the number of startable modules, the number of modules in each load state, and the cumulative frequency change ∑Δrps, the method for adjusting the compressor frequency of each module or performing loading and unloading operations includes: When Δrps ≥ 0, the compressor frequencies in modules with different load states are adjusted based on the comparison between the number of currently running modules and the number of startable modules, and the existence of modules in medium and low load states, and new modules are loaded when the conditions are met; When Δrps is less than 0, the compressor frequency of different load states is adjusted based on the existence of modules in high load state, the quantitative relationship between modules in medium load state and low load state, and the size of the cumulative frequency change, and the module is unloaded when the conditions are met.

8. The method for controlling loading and unloading compressors between multiple modules of an air source heat pump water heater according to claim 7, characterized in that: When Δrps ≥ 0, the compressor frequencies in modules with different load states are adjusted based on the comparison between the number of currently running modules and the number of startable modules, and the presence of modules in medium and low load states, and new modules are loaded when the conditions are met, including: (1) When Δrps ≥ 0, and MK 运行数 < MK 可启动数 And (MK 中负荷数 +MK 低负荷数 )>0: Cmpr 高负荷 Compressor frequency rps=rps_old; Cmpr 中负荷 Compressor frequency rps=rps_old+Δrps1, Δrps1 = Δrps × MK 总模块数 / (MK 中负荷数 + MK 低负荷数 ), and Δrps1 ≤ 5 rps; Cmpr 低负荷 Compressor frequency rps=rps_old+Δrps1, Δrps1 = Δrps × MK 总模块数 / (MK 中负荷数 + MK 低负荷数 ), and Δrps1 ≤ 5 rps; Among them, MK 运行数 The number of currently running modules; MK 可启动数 The number of bootable modules; MK 中负荷数 The number of modules in medium load state; MK 低负荷数 The number of modules in low load state; Cmpr 高负荷 It is a high load state module; Cmpr 中负荷 For the medium load state module; Cmpr 低负荷 It is a low load state module; rps is the frequency of the compressor in the next cycle; rps_old is the frequency of the compressor in the current cycle; MK 总模块数 is the total number of modules in the system; (2) When Δrps ≥ 0, and MK 运行数 < MK 可启动数 , and (MK 中负荷数 +MK 低负荷数 )=0, And ∑Δrps×MK 总模块数 <=5: Cmpr 高负荷 Compressor frequency rps=rps_old; (3) When Δrps ≥ 0, and MK 运行数 < MK 可启动数 And (MK 中负荷数 +MK 低负荷数 )=0, And ∑Δrps×MK 总模块数 >5 o'clock: Cmpr 高负荷 Compressor frequency rps=rps_old; Cmpr 中负荷 Compressor frequency rps=rps+Δrps; Cmpr 低负荷 Compressor frequency rps=rps+Δrps; When a new module is loaded, set ∑Δrps = 0 and start accumulating again from the next cycle; (4) When Δrps ≥ 0, and MK 运行数 = MK 可启动数 , and (MK 中负荷数 +MK 低负荷数 )>0: Cmpr 高负荷 Compressor frequency rps=rps_old; Cmpr 中负荷 Compressor frequency rps=rps_old+Δrps1, Δrps1 = Δrps × MK 总模块数 / (MK 中负荷数 + MK 低负荷数 ), and Δrps1 <= 5rps; Cmpr 低负荷 Compressor frequency rps=rps_old+Δrps1, Δrps1 = Δrps × MK 总模块数 / (MK 中负荷数 + MK 低负荷数 ), and Δrps1 <= 5 rps; (5) When Δrps ≥ 0, and MK 运行数 = MK 可启动数 , and (MK 中负荷数 +MK 低负荷数 )=0: Cmpr 高负荷 The compressor frequency rps=rps_old+Δrps, and Δrps<=3rps.

9. The method for controlling loading and unloading compressors between multiple modules of an air source heat pump water heater according to claim 8, characterized in that: When Δrps is less than 0, the compressor frequencies of different load states are adjusted based on the presence of modules in high load state, the relationship between the number of modules in medium load state and low load state, and the magnitude of the cumulative frequency change, and the modules are unloaded when the conditions are met, including: (1) When Δrps < 0, and MK 高负荷数 >0, and (MK 中负荷数 +MK 低负荷数 )>0: Cmpr 高负荷 Compressor frequency rps=rps_old+Δrps1, Δrps1 = Δrps × MK 总模块数 / MK 高负荷数 , and Δrps1 <= 10 rps; Cmpr 中负荷 Compressor frequency rps=rps_old; Cmpr 低负荷 Compressor frequency rps=rps_old; (2) When Δrps<0, and MK 高负荷数 >0, and (MK 中负荷数 +MK 低负荷数 )=0: Cmpr 高负荷 Compressor frequency rps=rps_old+Δrps, and Δrps<=10rps; (3) When Δrps<0, and MK 高负荷数 =0, and MK 低负荷数 =0 and MK 中负荷数 >0 hours: Cmpr 中负荷 Compressor frequency rps=rps_old+Δrps1, Δrps1 = Δrps × MK 总模块数 / MK 中负荷数 , and Δrps1 <= 10 rps; (4) When Δrps<0, and MK 高负荷数 =0 and MK 低负荷数 >0 and MK 中负荷数 >0 hours: Cmpr 中负荷 Compressor frequency rps=rps_old+Δrps1, Δrps1 = Δrps × MK 总模块数 / MK 低负荷数 , and Δrps1 <= 10 rps; Cmpr 低负荷 Compressor frequency rps=rps_old; (5) When Δrps<0, and MK 高负荷数 =0, and MK 低负荷数 >0 and MK 中负荷数 =0 and ∑Δrps>=-10: Cmpr 低负荷 Compressor frequency rps=rps_old; (6) When Δrps<0, and MK 高负荷数 =0 and MK 低负荷数 >0 and MK 中负荷数 =0 and ∑Δrps<-10: Unload a module, set ∑Δrps = 0, and start accumulating again from the next cycle.

10. The method for controlling loading and unloading of compressors between multiple modules of an air source heat pump water heater according to claim 8, wherein: When loading a new module, priority is given to loading the module with no faults in the system and the shortest running time; when unloading a module, priority is given to unloading the module with no faults in the system and the longest running time.

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