Unit control method, device, compressor system and storage medium

Abstract

The present disclosure provides a unit control method, device, compressor system and storage medium, relating to the technical field of automatic control. A unit control method of the present disclosure includes: determining the working states of the compressors in a compressor unit; and performing a predetermined load balancing operation if there are compressors with no load and the number of compressors with no load is a predetermined number, and if the average load is less than or equal to a predetermined first load. By such a method, unnecessary load balancing adjustments can be reduced and the efficiency of the load balancing operation can be improved.

Description

Technical Field

[0001] The present disclosure relates to the field of automatic control technologies, and particularly to a unit control method, apparatus, compressor system, and storage medium. Background Art

[0002] For a fixed-frequency screw compressor, the load regulation range is from 25% to 100%. Under specified working conditions, there is an optimal point in the load performance. For example, the energy efficiency is the highest when the load output is 75%.

[0003] Generally, for a unit according to the terminal load demand, most of the time the chiller operates at a partial load, and the compressor also loads and unloads according to the load demand. For example, the compressor is controlled to load and unload according to the water temperature: the customer sets a target water temperature. When the actual water temperature is higher than the target water temperature, the compressor loads; when the actual water temperature is lower than the target water temperature, the compressor unloads; otherwise, the compressor remains unchanged. Summary of the Invention

[0004] The inventors have found that for fixed-frequency units with large cooling capacities, multiple compressors are mostly used for modular combined control. In the solutions of the related technologies, there is a situation where some compressors are overloaded while some compressors are idle, and it is difficult to reach the optimal load point.

[0005] An object of the present disclosure is to propose a method for achieving load balance of a multi-compressor unit and improving the efficiency of load balance operations.

[0006] According to one aspect of some embodiments of the present disclosure, a unit control method is proposed, including: determining the working states of the compressors in the compressor unit; and performing a predetermined load balance operation if there are compressors with no load and the number of compressors with no load is a predetermined number and the average load is less than or equal to a predetermined first load.

[0007] In some embodiments, the predetermined load balance operation includes at least one of the following: if the real-time load of the compressor is less than a predetermined load lower limit, performing a compressor load loading operation; or if the real-time load of the compressor is greater than a predetermined load upper limit, performing a compressor load unloading operation.

[0008] In some embodiments, determining the working states of the compressors in the compressor unit includes: obtaining the real-time load of each compressor; and determining the average load according to the real-time load of each compressor.

[0009] In some embodiments, the predetermined number includes at least one of 1 or the number of compressors in the compressor unit - 1.

[0010] In some embodiments, the method further includes: when there is an unloaded compressor and there is a compressor whose continuous operation duration exceeds a predetermined duration threshold, starting the unloaded compressor to replace the compressor whose continuous operation duration exceeds the predetermined duration threshold to carry the load.

[0011] In some embodiments, starting the unloaded compressor to replace the compressor whose continuous operation duration exceeds the predetermined duration threshold to carry the load includes: determining a first compressor among the unloaded compressors; determining a second compressor among the compressors whose continuous operation duration exceeds the predetermined duration threshold; turning on the first compressor and turning off the second compressor, and having the first compressor carry the load of the second compressor, where the number of the first compressors is the same as the number of the second compressors.

[0012] In some embodiments, the number of the first compressors is 1; determining a second compressor among the compressors whose continuous operation duration exceeds the predetermined duration threshold includes: selecting one second compressor among the compressors whose continuous operation duration exceeds the predetermined duration threshold in the order of the compressor serial numbers.

[0013] In some embodiments, the compressor load loading operation includes at least one of the following: sending a first loading signal to the compressor to increase the load of the compressor until it reaches the target load, where the compressor is a steplessly adjustable compressor; or sending a second loading signal to the compressor to increase the load of the compressor according to a predetermined granularity, where the compressor is a step - adjustable compressor.

[0014] In some embodiments, the compressor load unloading operation includes at least one of the following: sending a first unloading signal to the compressor to increase the load of the compressor until it reaches the target load, where the compressor is a steplessly adjustable compressor; or sending a second unloading signal to the compressor to reduce the load of the compressor according to a predetermined granularity, where the compressor is a step - adjustable compressor.

[0015] In some embodiments, the method further includes: starting to time when starting the compressor unit; when the timing duration is greater than or equal to a predetermined first threshold, performing an operation of determining the working states of the compressors in the compressor unit.

[0016] In some embodiments, the compressor includes a fixed - frequency screw compressor of a multi - head water chiller unit.

[0017] According to one aspect of some embodiments of the present disclosure, a unit control device is provided, including: a state determination unit configured to determine the working states of the compressors in the compressor unit; an adjustment unit configured to perform a predetermined load balancing operation when there is an unloaded compressor and the number of the unloaded compressors is a predetermined number and the average load is less than or equal to a predetermined first load.

[0018] In some embodiments, the state determination unit is configured to obtain the real-time load of each compressor and determine the average load according to the real-time load of each compressor.

[0019] In some embodiments, the adjustment unit is further configured to: in the case where there is a compressor with no load and there is a compressor with a continuous operation duration exceeding a predetermined duration threshold, start the compressor with no load to replace the compressor with a continuous operation duration exceeding the predetermined duration threshold to carry the load.

[0020] In some embodiments, the device further includes: a timing unit configured to start timing when starting the compressor unit, and activate the state determination unit when the timing duration is greater than or equal to a predetermined first threshold.

[0021] According to one aspect of some embodiments of the present disclosure, a unit control device is provided, including: a memory; and a processor coupled to the memory, the processor being configured to execute any one of the above unit control methods based on instructions stored in the memory.

[0022] According to one aspect of some embodiments of the present disclosure, a non-transitory computer-readable storage medium is provided, on which computer program instructions are stored, and when the instructions are executed by a processor, the steps of any one of the above unit control methods are implemented.

[0023] According to one aspect of some embodiments of the present disclosure, a compressor system is provided, including: any one of the above unit control devices; and a compressor unit configured to adjust the load under the control of the unit control device.

[0024] In some embodiments, the compressor unit is further configured to pressurize the refrigerant, obtain refrigerant gas, and transmit it to the air-cooled heat exchanger; the system further includes: an air-cooled heat exchanger configured to reduce the temperature of the refrigerant gas, obtain refrigerant liquid, and transmit it to the electronic expansion valve; an electronic expansion valve configured to reduce the pressure of the refrigerant liquid and transmit it to the cold water side heat exchanger; and a cold water side heat exchanger configured to use the refrigerant liquid to absorb the heat of water to reduce the water temperature and transmit the refrigerant liquid back to the compressor unit. Description of the Drawings

[0025] The drawings described herein are used to provide a further understanding of the present disclosure, and constitute a part of the present disclosure. The illustrative embodiments and descriptions of the present disclosure are used to explain the present disclosure and do not constitute an improper limitation of the present disclosure. In the drawings:

[0026] Figure 1 It is a flowchart of some embodiments of the unit control method of the present disclosure.

[0027] Figure 2 It is a flowchart of other embodiments of the unit control method of the present disclosure.

[0028] Figure 3 Flow chart of some other embodiments of the unit control method of the present disclosure.

[0029] Figure 4 Schematic diagram of some embodiments of the unit control device of the present disclosure.

[0030] Figure 5 Schematic diagram of some other embodiments of the unit control device of the present disclosure.

[0031] Figure 6 Schematic diagram of some other embodiments of the unit control device of the present disclosure.

[0032] Figure 7 Schematic diagram of some embodiments of the compressor system of the present disclosure. Detailed implementation manners

[0033] The technical solutions of the present disclosure will be further described in detail below with reference to the drawings and embodiments.

[0034] The flow chart of some embodiments of the unit control method of the present disclosure is as Figure 1 shown.

[0035] In step 130, determine the working states of the compressors in the compressor unit. In some embodiments, the loads of the compressors in the compressor unit can be obtained. In some embodiments, the average value can also be calculated based on the loads of the compressors as the average load for subsequent use. In some embodiments, the loads of the compressors can be represented in percentage form, that is, representing the percentage of the current load of the compressor to the full load.

[0036] In step 150, determine whether there are compressors with no load and the number of compressors with no load is a predetermined number. In some embodiments, the predetermined number can be one or more discrete values. If there are compressors with no load and the number of compressors with no load is the predetermined number, then execute step 160; otherwise, do not perform load balancing adjustment and return to step 130 to continue monitoring the working states of the compressors.

[0037] In some embodiments, the predetermined number can include 1 to n 1 , where n 1 is an integer greater than 1 and less than N, N is the number of compressors (heads) in the compressor unit, N is an integer greater than 1, and the value of n 1 can be set or adjusted as needed. In some embodiments, n 1= 1. By such a method, according to the state where there is an unloaded compressor and the number of unloaded compressors is small, it is determined that the compressor unit is in a state with a relatively large load and not in a state with a very small load, and there is a relatively high possibility of load imbalance, thereby reducing unnecessary load balance adjustments and improving the efficiency of load balance operations.

[0038] In some embodiments, the predetermined quantity may include n 2 ~ N - 1, where n 2 is an integer greater than n 1 , less than n - 1, N is the number of compressors (heads) in the compressor unit, N is an integer greater than 1, and the value of n 2 can be set or adjusted as needed. In some embodiments, n 2 = n - 1. By such a method, load balance adjustment can be performed only when the load is concentrated on a very small number of compressors, reducing unnecessary load balance adjustments and improving the efficiency of load balance operations.

[0039] In some embodiments, the predetermined quantity may simultaneously include 1 ~ n 1 and n 2 ~ N - 1, so as to be able to screen out the situation where the load is relatively large and relatively concentrated according to the number of idle compressors, while improving the efficiency of load balance operations and reducing the probability of missed adjustment.

[0040] In step 160, it is judged whether the average load of the compressors is less than or equal to a predetermined first load. In some embodiments, the predetermined first load is the load value at the optimal load point of the compressor. In some embodiments, if the compressors in the compressor unit have the same optimal load point (for example, 75% load), then the predetermined first load = the load values at the optimal load points of each compressor. In some embodiments, if the compressors in the compressor unit have different optimal load points, then the predetermined first load = the average value of the load values at the optimal load points of each compressor.

[0041] In some embodiments, if the average load of the compressors is less than or equal to the predetermined first load, then step 170 is executed; otherwise, no load balance adjustment is performed, and the process returns to step 130 to continue monitoring the working state of the compressors.

[0042] By such a method, the situation where the compressor loads are generally small can be screened out through the average load of the compressor unit, further reducing unnecessary load balance adjustments and improving the efficiency of load balance operations.

[0043] In step 170, a predetermined load balance operation is executed.

[0044] In some embodiments, the predetermined load balancing operation includes, for each compressor in the compressor unit, if the real-time load of the compressor is less than the predetermined lower load limit, performing a compressor load increasing operation. In some embodiments, the predetermined load balancing operation includes, for each compressor in the compressor unit, if the real-time load of the compressor is greater than the predetermined upper load limit, performing a compressor load decreasing operation. In some embodiments, the predetermined load balancing operation includes, for each compressor in the compressor unit, if the real-time load is less than or equal to the predetermined upper load limit and greater than or equal to the predetermined lower load limit, no adjustment is required.

[0045] In some embodiments, the above-mentioned predetermined upper load limit and predetermined lower load limit may be determined based on the above-mentioned predetermined first load Q g and the predetermined deviation value. For example, if the predetermined deviation value allowed for the unit load is X, then the predetermined upper load limit = Q g + |X|, and the predetermined lower load limit = Q g - |X|. In some embodiments, the value range of X may be -10% to +10%, such as +5%. By such a method, the load of each compressor can be controlled within the range of the allowable deviation centered on the optimal load point, thereby achieving the load balance of each compressor in the compressor unit.

[0046] Based on the method in the above embodiments, it is possible to use the presence of idle compressors in the compressor unit and the number of idle compressors meeting the predetermined number as the trigger point, combined with the determination of the possible concentration of load according to the average load, and then trigger the execution of load balance adjustment, thereby reducing unnecessary load balance adjustments and improving the efficiency of the load balancing operation.

[0047] The flowchart of another embodiment of the unit control method of the present disclosure is as Figure 2 shown.

[0048] In step 211, timing starts when the compressor unit is started.

[0049] In step 212, it is judged whether the timing duration is greater than or equal to the predetermined first threshold. In some embodiments, when the running time of the compressor unit is greater than or equal to the predetermined first threshold, it is determined that the compressor unit is operating in a relatively stable state, and subsequent step 231 can be executed; if the timing duration is less than the predetermined first threshold, return to step 212 to continue timing and waiting until the running time of the compressor unit is greater than or equal to the predetermined first threshold. In some embodiments, the predetermined first threshold may be 10 to 60 minutes, such as 20 minutes.

[0050] In step 231, the real-time load Q s (n) of each compressor is obtained, where n is the compressor identifier, and n is a positive integer from 1 to N, and N is the number of compressors in the compressor unit.

[0051] In step 232, the average load is determined according to the real-time loads of the respective compressors, such as the average load Q p =(Q s (1)+Q s (2)+……+Q s (N)) / N.

[0052] In step 251, it is judged whether there is a compressor with no load and the number of compressors with no load is a predetermined number. If there is a compressor with no load and the number of compressors with no load is a predetermined number, then step 261 is executed; otherwise, return to step 231 to continue load monitoring

[0053] In some embodiments, it can be determined according to the load of the compressor whether there is exactly one compressor with load (i.e., the number of compressors with no load is N - 1), or the situation where there is exactly one compressor with no load. If it is determined that there is exactly one compressor with load, or the situation where there is exactly one compressor with no load, then step 261 is executed; otherwise, return to step 231 to continue load monitoring

[0054] In step 261, it is judged whether the average load of the compressor is less than or equal to a predetermined first load. In some embodiments, the predetermined first load is the load value at the optimal load point of the compressor. In some embodiments, if the average load of the compressor is less than or equal to the predetermined first load, then steps 271, 272 and 273 are executed; otherwise, no load balancing adjustment is performed and return to step 231 to continue monitoring the working state of the compressor

[0055] In step 271, for the compressor n with a real-time load Qs(n) less than the predetermined load lower limit Q g -|X|, a compressor load loading operation is performed, and then return to step 231 to continue monitoring the working state of the compressor

[0056] In step 272, for the compressor n with a real-time load Qs(n) greater than or equal to the predetermined load lower limit Q g -|X| and less than or equal to the predetermined load upper limit Q g +|X|, no adjustment is made, and then return to step 231 to continue monitoring the working state of the compressor

[0057] In step 273, for the compressor n with a real-time load Qs(n) greater than the predetermined load upper limit Q g +|X|, a compressor load unloading operation is performed, and then return to step 231 to continue monitoring the working state of the compressor

[0058] Based on the method in the above - shown embodiments, it can operate after the compressor unit has been running for a period of time, avoiding meaningless adjustments in the case of unstable working conditions with a short startup time, and improving the efficiency of load - balance regulation. Taking the optimal load point as a benchmark, two - way regulation is performed on the compressor loads that are too large or too small, making them approach the optimal load point, improving the energy efficiency of each compressor in the compressor unit, and thus achieving load balance.

[0059] In some embodiments, in addition to regulating the compressor load, for the situation where some compressors in the compressor unit keep running while some compressors keep idle, the compressor control method of the present application further includes that, when it is determined that there are unloaded compressors and there are compressors whose continuous running duration exceeds a predetermined duration threshold, start the unloaded compressors to replace the compressors whose continuous running duration exceeds the predetermined duration threshold to bear the load. By such a method, the loss of some compressors can be reduced, and the service life of the equipment can be extended.

[0060] In some embodiments, the method of one - to - one replacement work of compressors can be adopted. Determine the first compressor among the unloaded compressors; determine the second compressor among the compressors whose continuous running duration exceeds the predetermined duration threshold; turn on the first compressor and turn off the second compressor, and let the first compressor bear the load of the second compressor, where the number of the first compressors is the same as the number of the second compressors. By such a method, the compressor being turned off and the compressor bearing its load can be the same. While allowing the continuously working compressors to rest, the load balance is prevented from being damaged, and the ability to maintain the load balance is improved.

[0061] The flowchart of some embodiments of the unit control method of the present disclosure is as Figure 3 shown.

[0062] In step 311, start timing after the compressor unit starts, and determine whether the startup time of the compressor unit is ≥ a predetermined first threshold T 0 . In some embodiments, when the running time of the compressor unit ≥ T 0 , perform the subsequent step 331; if the running time of the compressor unit < T 0 , continue timing and waiting until the running time of the compressor unit is greater than or equal to T 0 .

[0063] In step 331, determine the working states of the compressors in the compressor unit. In some embodiments, obtain the real - time load Qs(n) of each compressor, where n is the compressor identifier, and n is a positive integer from 1 to N, and N is the number of compressors in the compressor unit. In some embodiments, the average load Q can also be determined according to the real - time loads of each compressor p . Then, perform step 341 and step 351 respectively.

[0064] In step 341, it is judged whether there is a compressor n with Qs(n) = 0. If so, step 342 is executed; otherwise, return to step 331 to continue monitoring the working state of the compressor.

[0065] In step 342, it is judged whether there is a compressor among the compressors with Qs(n) ≠ 0 whose fault-free continuous operation time is greater than or equal to the predetermined duration threshold T r If there is a continuous fault-free operation time T r , then step 343 is executed; otherwise, return to step 331 to continue monitoring the working state of the compressor. In some embodiments, the relationship between the compressor head and the compressor shown in the figure is one-to-one, and the adjustment of the compressor head is equivalent to the adjustment of the corresponding compressor. In some embodiments, T r can take any value within 10 to 60 minutes, such as 48 minutes.

[0066] In step 343, turn off one compressor whose fault-free continuous operation time is greater than or equal to Tr, and start a non-loaded compressor, and then return to step 331 to continue monitoring the working state of the compressor.

[0067] In some embodiments, if the number of compressors whose fault-free continuous operation time is greater than or equal to Tr is greater than 1, one compressor can be selected according to a predetermined rule, and its work is replaced by a non-loaded compressor. In some embodiments, based on a preset priority, or in the order of the compressor numbers, the compressor with the smallest or largest number among the compressors whose fault-free continuous operation time is greater than or equal to Tr can be selected to stop running, and the current non-loaded compressor replaces it to bear the load. In some embodiments, the compressors can be numbered in advance, such as Module 1, 2, 3, etc. Then return to step 331, and in the next cycle, stop the operation of the next compressor whose fault-free continuous operation time is greater than or equal to Tr according to the predetermined rule, and the non-loaded compressor replaces it to bear the load.

[0068] By such a method, it is possible to stop the operation of only one compressor in each cycle, and a free compressor bears its load. On the one hand, it ensures that the currently free compressor can bear the released load, and on the other hand, it reduces the number of compressors adjusted at one time, avoids large fluctuations in the working state of the equipment, and ensures the stable operation of the equipment.

[0069] In step 351, it is judged whether there is a situation where there is exactly one Qs(n) = 0 or exactly one Qs(n) ≠ 0. If there is exactly one Qs(n) = 0, or exactly one Qs(n) ≠ 0, then step 361 is executed.

[0070] In step 361, it is judged whether the average load Q p≤ Predetermined first load Q g If Q p ≤ Q g , step 371 is executed; otherwise, step 372 is executed.

[0071] In step 371, for each compressor, if Qs(n) < Qg - X, compressor n is loaded; if Qs(n) > Qg + X, compressor n is unloaded; if Qg - X ≤ Qs(n) ≤ Qg + X, the state of compressor n remains unchanged.

[0072] In some embodiments, in the case where the compressor is a continuously adjustable compressor, the compressor can be loaded by sending a first loading signal to the compressor. In some embodiments, the compressor receives the load of the first loading signal until the target load is reached. In some embodiments, the target load can be the predetermined first load or any load between the lower limit and the upper limit of the predetermined load. In some embodiments, in the case where the compressor is a step - adjustable compressor, a second loading signal can be sent to the compressor so that the compressor increases its load according to a predetermined granularity. For example, each time the compressor receives the second loading signal, the load is increased by a predetermined amount (e.g., 10% - 25%). Through multiple predetermined load balancing operations, load balance is achieved. By such a method, different control operations can be executed according to the characteristics of the compressor, expanding the application range.

[0073] In some embodiments, in the case where the compressor is a continuously adjustable compressor, the compressor can be unloaded by sending a first unloading signal to the compressor. In some embodiments, the compressor receives the load of the first unloading signal until the target load is reached. In some embodiments, the target load can be the predetermined first load or any load between the lower limit and the upper limit of the predetermined load. In some embodiments, in the case where the compressor is a step - adjustable compressor, a second unloading signal can be sent to the compressor so that the compressor reduces its load according to a predetermined granularity. For example, each time the compressor receives the second unloading signal, the load is increased by a predetermined amount (e.g., 10% - 25%). Through multiple predetermined load balancing operations, load balance is achieved. By such a method, different control operations can be executed according to the characteristics of the compressor, expanding the application range.

[0074] In step 372, load balance control is not entered, and the process returns to step 331 to continue monitoring the working state of the compressor.

[0075] Based on the method in the above - shown embodiments, it can ensure that the currently idle compressor can bear the released load, avoid large fluctuations in the working state of the equipment, ensure the stable operation of the equipment; improve the efficiency of load balance adjustment, improve the energy efficiency of each compressor in the compressor unit, and thus achieve load balance.

[0076] Schematic diagrams of some embodiments of the unit control device 41 of the present disclosure are as follows Figure 4 shown

[0077] The state determination unit 412 can determine the operating states of the individual compressors in the compressor unit. In some embodiments, the loads of the individual compressors in the compressor unit can be obtained. In some embodiments, the average value can also be calculated based on the loads of the individual compressors and used as the average load for subsequent use. In some embodiments, the loads of the individual compressors can be expressed in percentage form, i.e., representing the percentage of the current compressor load to the full load

[0078] The adjustment unit 413 can further determine whether the average load of the compressors is less than or equal to a predetermined first load when there are compressors with no load and the number of compressors with no load is a predetermined number. If the average load of the compressors is less than or equal to the predetermined first load, a predetermined load balancing operation is performed

[0079] In some embodiments, the predetermined load balancing operation includes, for each compressor in the compressor unit, if the real-time load of the compressor is less than the predetermined load lower limit, performing a compressor load loading operation. In some embodiments, the predetermined load balancing operation includes, for each compressor in the compressor unit, if the real-time load of the compressor is greater than the predetermined load upper limit, performing a compressor load unloading operation. In some embodiments, the predetermined load balancing operation includes, for each compressor in the compressor unit, if the real-time load is less than or equal to the predetermined load upper limit and greater than or equal to the predetermined load lower limit, no adjustment is required

[0080] Such a device can use the presence of idle compressors in the compressor unit and the number of idle compressors meeting the predetermined number as a trigger point, combine with the determination of possible concentrated loads based on the average load, and then trigger the execution of load balancing adjustment, thereby reducing unnecessary load balancing adjustments and improving the efficiency of load balancing operations

[0081] In some cases, the adjustment unit 413 can also start the compressors with no load to replace the compressors with a continuous operation duration exceeding the predetermined duration threshold to carry the load when it is determined that there are compressors with no load and there are compressors with a continuous operation duration exceeding the predetermined duration threshold. Such a device can reduce the wear of some compressors and extend the service life of the equipment

[0082] In some embodiments, as Figure 4As shown, the unit control device 41 may further include a timing unit 411, which can start timing when the compressor unit is started, and activate the state determination unit 412 when the timing duration is greater than or equal to a predetermined first threshold; during the period from the start of the compressor unit to the timing duration reaching the predetermined first threshold, the state determination unit 412 does not operate, so that it can operate after the compressor unit has been running for a period of time, avoiding meaningless adjustments in the case of unstable working states with a short startup time, and improving the efficiency of load balance adjustment.

[0083] A schematic structural diagram of an embodiment of the unit control device of the present disclosure is as Figure 5 shown. The unit control device includes a memory 501 and a processor 502. Among them: The memory 501 can be a disk, a flash memory, or any other non-volatile storage medium. The memory is used to store the instructions in the corresponding embodiments of the unit control method described above. The processor 502 is coupled to the memory 501 and can be implemented as one or more integrated circuits, such as a microprocessor or a microcontroller. The processor 502 is used to execute the instructions stored in the memory, and can improve the efficiency of load balance operations.

[0084] In one embodiment, it can also be as Figure 6 shown. The unit control device 600 includes a memory 601 and a processor 602. The processor 602 is coupled to the memory 601 through the BUS bus 603. The unit control device 600 can also be connected to an external storage device 605 through a storage interface 604 to call external data, and can also be connected to a network or another computer system (not shown) through a network interface 606. Details are not described here.

[0085] In this embodiment, by storing data instructions in the memory and then processing the above instructions by the processor, the efficiency of load balance operations can be improved.

[0086] In another embodiment, a computer-readable storage medium stores computer program instructions, and when the instructions are executed by a processor, the steps of the method in the corresponding embodiment of the unit control method are implemented. Those skilled in the art should understand that the embodiments of the present disclosure can be provided as methods, devices, or computer program products. Therefore, the present disclosure can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present disclosure can adopt the form of a computer program product implemented on one or more computer-usable non-transitory storage media (including but not limited to disk memories, CD-ROMs, optical memories, etc.) containing computer-usable program codes.

[0087] Schematic diagrams of some embodiments of the compressor system of the present disclosure are as Figure 7As shown in the figure. The compressor system includes a unit control device 71 and a compressor unit 721.

[0088] The unit control device 71 can be any one of those mentioned above.

[0089] The compressor unit 721 can adjust the load under the control of the unit control device 71. In some embodiments, in addition to being controlled by the unit control device 71 to adjust the load, the compressors in the compressor unit are also loaded and unloaded according to the load demand. For example, for a water chiller, the loading and unloading are controlled according to the water temperature: the customer sets a target water temperature. When the actual water temperature is higher than the target water temperature, the compressor is loaded; when the actual water temperature is lower than the target water temperature, the compressor is unloaded; otherwise, the compressor remains (neither loaded nor unloaded).

[0090] Such a compressor system can take the existence of idle compressors in the compressor unit and the number of idle compressors meeting the predetermined number as the trigger point, combine with the determination of possible concentrated load situations according to the average load, and then trigger the execution of load balancing adjustment, thereby reducing unnecessary load balancing adjustments and improving the efficiency of load balancing operations.

[0091] In some embodiments, as Figure 7 shown in the figure, the compressor system further includes an air-cooled heat exchanger 722, an electronic expansion valve 723, and a cold water side heat exchanger 724. In some embodiments, the compressors in the compressor unit can be fixed-frequency screw compressors of a multi-head water chiller.

[0092] The compressor unit 721 can pressurize the refrigerant to generate refrigerant gas and transmit it to the air-cooled heat exchanger; the air-cooled heat exchanger 722 can reduce the temperature of the refrigerant gas to obtain refrigerant liquid and transmit it to the electronic expansion valve; the electronic expansion valve 723 can reduce the pressure of the refrigerant liquid and transmit it to the cold water side heat exchanger; the cold water side heat exchanger 724 can use the refrigerant liquid to absorb the heat of water to reduce the water temperature and transmit the refrigerant liquid back to the compressor unit.

[0093] Such a multi-head unit can use the refrigerant for heat exchange and refrigeration, and based on the control of the unit control device during operation, achieve load balancing of each compressor in the compressor unit, reduce unnecessary load balancing adjustments, and improve the efficiency of load balancing operations.

[0094] This disclosure is described with reference to the flowcharts and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the disclosure. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and combinations of flows and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, such that the instructions executed by the processor of the computer or other programmable data processing device produce a means for implementing the functions specified in one flow Figure 1 one flow or multiple flows and / or blocks Figure 1 or a means for implementing the functions specified in one block or multiple blocks.

[0095] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, such that the instructions stored in the computer-readable memory produce a manufacture including an instruction means that implements the functions specified in one flow Figure 1 one flow or multiple flows and / or blocks Figure 1 or a means for implementing the functions specified in one block or multiple blocks.

[0096] These computer program instructions can also be loaded onto a computer or other programmable data processing device, such that a series of operation steps are executed on the computer or other programmable device to produce a computer-implemented process, and thus the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one flow Figure 1 one flow or multiple flows and / or blocks Figure 1 or a means for implementing the functions specified in one block or multiple blocks.

[0097] So far, this disclosure has been described in detail. To avoid obscuring the concept of this disclosure, some details known in the art have not been described. Those skilled in the art can fully understand how to implement the technical solutions disclosed herein based on the above description.

[0098] The methods and apparatuses of this disclosure can be implemented in many ways. For example, the methods and apparatuses of this disclosure can be implemented by software, hardware, firmware, or any combination of software, hardware, and firmware. The above order of steps for the methods is only for illustration, and the steps of the methods of this disclosure are not limited to the specific order described above, unless otherwise specifically stated. In addition, in some embodiments, this disclosure can also be implemented as a program recorded in a recording medium, and these programs include machine-readable instructions for implementing the methods according to this disclosure. Therefore, this disclosure also covers a recording medium storing a program for executing the methods according to this disclosure.

[0099] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present disclosure and not to limit them; although the present disclosure has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that it is still possible to modify the specific implementation manners of the present disclosure or perform equivalent replacements for some technical features; without departing from the spirit of the technical solutions of the present disclosure, they should all be covered within the scope of the technical solutions claimed in the present disclosure.

Claims

1. A unit control method, comprising: determining the working states of the compressors in the compressor unit; when there are unloaded compressors and the number of unloaded compressors is a predetermined number, if the average load is less than a predetermined first load, performing a predetermined load balancing operation, including at least one of the following: if the real-time load of a compressor is less than a predetermined load lower limit, performing a compressor load increasing operation; or if the real-time load of a compressor is greater than a predetermined load upper limit, performing a compressor load decreasing operation.

2. The method according to claim 1, wherein, the determining the working states of the compressors in the compressor unit includes: acquiring the real-time load of each compressor; determining the average load according to the real-time load of each compressor.

3. The method according to claim 1, wherein, the predetermined number includes at least one of 1 or the number of compressors in the compressor unit - 1.

4. The method according to claim 1, further comprising: when there are unloaded compressors and there are compressors with a continuous operation duration exceeding a predetermined duration threshold, starting the unloaded compressors to replace the compressors with a continuous operation duration exceeding the predetermined duration threshold to bear the load.

5. The method according to claim 4, wherein, the starting the unloaded compressors to replace the compressors with a continuous operation duration exceeding the predetermined duration threshold to bear the load includes: determining a first compressor among the unloaded compressors; determining a second compressor among the compressors with a continuous operation duration exceeding the predetermined duration threshold; turning on the first compressor and turning off the second compressor, and the first compressor bears the load of the second compressor, wherein the number of the first compressors is the same as the number of the second compressors.

6. The method according to claim 4 or 5, wherein, the number of the first compressors is 1; the determining the second compressor among the compressors with a continuous operation duration exceeding the predetermined duration threshold includes: selecting one second compressor among the compressors with a continuous operation duration exceeding the predetermined duration threshold in the order of compressor serial numbers.

7. The method according to claim 1, wherein, the compressor load increasing operation includes at least one of the following: sending a first increasing signal to the compressor to increase the load of the compressor until it reaches the target load, wherein the compressor is a steplessly adjustable compressor; or sending a second increasing signal to the compressor to increase the load of the compressor in a predetermined granularity, wherein the compressor is a stepwise adjustable compressor.

8. The method according to claim 1, wherein, the compressor load decreasing operation includes at least one of the following: sending a first decreasing signal to the compressor to increase the load of the compressor until it reaches the target load, wherein the compressor is a steplessly adjustable compressor; or sending a second decreasing signal to the compressor to decrease the load of the compressor in a predetermined granularity, wherein the compressor is a stepwise adjustable compressor.

9. The method according to claim 1, further comprising: starting to time when starting the compressor unit; When the timing duration is greater than or equal to a predetermined first threshold, perform the operation of determining the working states of the compressors in the compressor unit.

10. The method according to claim 1, wherein, the compressor includes a fixed-frequency screw compressor of a multi-head water chiller.

11. A unit control device, comprising: a state determination unit configured to determine the working states of the compressors in the compressor unit; an adjustment unit configured to, when there are unloaded compressors and the number of unloaded compressors is a predetermined number, if the average load is less than a predetermined first load, perform a predetermined load balancing operation, including at least one of the following: if the real-time load of the compressor is less than a predetermined load lower limit, perform a compressor load loading operation; or if the real-time load of the compressor is greater than a predetermined load upper limit, perform a compressor load unloading operation.

12. The device according to claim 11, wherein, the state determination unit is configured to obtain the real-time load of each compressor and determine the average load according to the real-time load of each compressor.

13. The device according to claim 11, wherein, the adjustment unit is further configured to: when there are unloaded compressors and there are compressors with a continuous operation duration exceeding a predetermined duration threshold, start the unloaded compressors to replace the compressors with a continuous operation duration exceeding the predetermined duration threshold to bear the load.

14. The device according to claim 11, further comprising: a timing unit configured to start timing when the compressor unit is started, and activate the state determination unit when the timing duration is greater than or equal to a predetermined first threshold.

15. A unit control device, comprising: a memory; and a processor coupled to the memory, the processor being configured to execute the method according to any one of claims 1 to 10 based on instructions stored in the memory.

16. A non-transitory computer-readable storage medium having computer program instructions stored thereon, which when executed by a processor implement the steps of the method according to any one of claims 1 to 10.

17. A compressor system, comprising: the unit control device according to any one of claims 11 to 15; and a compressor unit configured to adjust the load under the control of the unit control device.

18. The system according to claim 17, wherein, the compressor unit is further configured to pressurize the refrigerant, obtain refrigerant gas, and transmit it to the air-cooled heat exchanger; further comprising: an air-cooled heat exchanger configured to reduce the temperature of the refrigerant gas, obtain refrigerant liquid, and transmit it to the electronic expansion valve; an electronic expansion valve configured to reduce the pressure of the refrigerant liquid and transmit it to the cold water side heat exchanger; and a cold water side heat exchanger configured to use the refrigerant liquid to absorb the heat of water to reduce the water temperature and transmit the refrigerant liquid back to the compressor unit.

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