Control method and system for unit loading of multi-unit cascade system and storage medium

Abstract

The invention relates to an air conditioner control technology, discloses a control method and system for unit loading of a multi-unit cascade system and a storage medium, and aims to realize stable and quick response of the system when user demands change and reduce system oscillation operation caused by demand change. According to the method, when a system is put into unit operation for the first time, the theoretical value of the current unit input number is calculated through a unit input number algorithm; controlling the loading number of the units according to the comparison of the theoretical value of the current unit input number and the number of the current operable units of the system; in the system operation process, if the capacity requirement changes or the number of the currently operable units is increased, the number of the input units is calculated again, and then unit loading control is carried out according to the number of the currently actual operation units and the number of the currently operable units. The method is suitable for a multi-machine cascade system.

Description

Technical Field

[0001] The present invention relates to air conditioning control technology, and in particular to a control method, system and storage medium for loading of units in a multi-machine cascade system. Background Art

[0002] In traditional technology, commercial multi-machine cascade systems mostly use fixed-frequency compressors, and the system loading method used is mostly based on the temperature difference to determine the loading and unloading intervals. For example, when the temperature difference is greater than the preset value, the unit is in the loading area and periodically loads a module; when the temperature is within the preset value range, the unit does not perform loading and unloading control; when the temperature difference is less than the preset value, the unit periodically unloads a module. With the home use and increasing frequency conversion of multi-machine cascade systems, the system loading and unloading adjustment is more sophisticated, which adjusts the operating frequency of the compressor, and then loads and unloads the unit according to the calculated frequency.

[0003] In the prior art, when the system is powered on for the first time, the number of units loaded for the first time will be calculated based on the temperature difference between the set temperature and the actual temperature, as well as the system heating capacity and the number of system modules. Subsequently, the loading and unloading control of the running units will be performed based on the set temperature, water temperature change and correlation coefficient, as well as the currently running units and the system as the relevant control coefficient. For example, when the system has N units, when the system is powered on and there is a capacity demand, if only M units can be operated. The number of units loaded for the first time is calculated to be X (X>M). When the difference is large, the actual number of units loaded for the first time is M. The frequency of the loaded M systems will quickly increase to the maximum value when the capacity demand remains unchanged. When the state of the unit that could not be loaded originally becomes an operational state during the frequency increase control process, the system will load 1 unit control when the frequency is increased to the loading platform, thereby completing the system capacity demand loading request. Specifically, after the Mth unit is increased to the loading platform, the M+1th unit is loaded. When the M+1th unit is increased to the loading platform, the M+2th unit is loaded, and so on. At this time, the system takes a long time to respond to the user.

[0004] There are usually two solutions to the problem of long system response time to users: the first is to increase the system frequency upgrade speed; the second is to optimize the algorithm for the number of units put into use based on the existing solution, and at the same time, recalculate the number of units put into use according to system changes, so as to achieve rapid cooling and heating response of the system and improve user experience.

[0005] For the first method, since the system frequency increase rate is limited, a too fast frequency increase rate will increase the risk of reliable operation of the system. The second method can quickly respond to user needs and avoid the risk of unstable operation caused by too fast frequency increase. In view of this, the present invention proposes to use the second method to solve the problem of long system response time to users. Summary of the invention

[0006] The technical problem to be solved by the present invention is to propose a control method, system and storage medium for loading of multi-machine cascade system units, so as to achieve stable and rapid response of the system when user demand changes, and reduce system oscillation caused by demand changes.

[0007] The technical solution adopted by the present invention to solve the above technical problems is:

[0008] In one aspect, the present invention provides a method for controlling the loading of a multi-machine cascade system unit, comprising the following steps:

[0009] When the system puts the unit into operation for the first time, it calculates the theoretical value of the current number of units put into operation through the unit input quantity algorithm;

[0010] If the theoretical value of the current number of units put into operation is greater than the number of units that can currently be operated in the system, the actual number of units loaded is the number of units that can currently be operated in the system, otherwise, it is the theoretical value of the current number of units put into operation;

[0011] When the system is in operation, if the capacity demand changes or the first actual loading quantity is the number of operable units of the system, and the current number of operable units increases, the theoretical value of the current number of unit inputs is calculated again using the unit input quantity algorithm; unit loading control is performed using the recalculated theoretical value of the current number of unit inputs, the current actual number of operating units, and the current number of operable units.

[0012] Furthermore, the algorithm for determining the number of units put into operation adopts the following formula:

[0013]

[0014] Among them, N L is the theoretical value of the number of units put into use; T set is the set temperature; T ctr is to control the water temperature; P is the unit cooling and heating capacity coefficient; M is the number of system units; L X It is the capacity configuration coefficient, which is calculated based on the ratio of system output capacity to current actual demand capacity.

[0015] Furthermore, the unit loading control is performed by recalculating the theoretical value of the current number of units put into operation, the current number of actually operating units, and the current number of operable units, including:

[0016] If the theoretical value of the current number of units put into operation is calculated again, N L Greater than the current actual number of operating units N R , and the theoretical value of the current number of units put into use is calculated again L Greater than or equal to the number of currently operable units N EN , and the number of currently operable units is N ENGreater than the current actual number of operating units N R , then the system load (N EN -N R ) units;

[0017] If the theoretical value of the current number of units put into operation is calculated again, N L Greater than the current actual number of operating units N R , and the theoretical value of the current number of units put into use is calculated again L Less than the current number of operable units N EN , then the system load (N L -N R ) units.

[0018] Furthermore, after calculating the current theoretical value of the unit input quantity through the unit input quantity algorithm, if the calculated theoretical value of the input quantity is greater than 0 and less than or equal to 1, the final theoretical value of the input quantity is 1; if the calculated theoretical value of the input quantity is greater than 1, the final theoretical value of the input quantity is obtained by rounding down.

[0019] In a second aspect, the present invention further provides a control system for loading units of a multi-machine cascade system, which comprises a processor and a memory, wherein the memory stores a computer program, and the processor implements the steps of the above-mentioned control method for loading units of a multi-machine cascade system by executing the computer program.

[0020] In a third aspect, the present invention further provides a storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the above-mentioned method for controlling loading of a multi-machine cascade system unit.

[0021] The beneficial effects of the present invention are:

[0022] The present invention optimizes the algorithm for the number of units put into operation, recalculates the number of units put into operation according to system changes, and then performs unit loading control according to the current actual number of operating units and the current number of operable units, thereby achieving a rapid cooling and heating response of the system and improving user experience. In addition, the present invention introduces a capacity configuration coefficient into the formula for calculating the number of units put into operation to actively adapt to changes in user demand and reduce system oscillation caused by changes in total demand. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a flow chart of the first loading of a unit by the system in an embodiment of the present invention;

[0024] Figure 2 This is a flow chart of theoretical value processing of the number of units put into operation in an embodiment of the present invention;

[0025] Figure 3This is a flow chart of loading a unit when the capacity demand changes in an embodiment of the present invention. DETAILED DESCRIPTION

[0026] The present invention aims to provide a control method, system and storage medium for loading of units in a multi-machine cascade system, so as to achieve stable and rapid response of the system when user demand changes, and reduce the system oscillation caused by demand changes. The core idea is: when the system is put into operation for the first time, the theoretical value of the current number of units put into operation is calculated by the unit input quantity algorithm; the loading quantity of the units is controlled according to the comparison between the current theoretical value of the number of units put into operation and the number of units currently operable in the system; during the operation of the system, if the capacity demand changes or the number of currently operable units increases, the number of units put into operation is calculated again, and then the unit loading control is performed according to the current actual number of operating units and the current number of operable units, so as to achieve rapid cooling and heating response of the system and improve user experience; in addition, the present invention actively adapts to changes in user demand by introducing a capacity configuration coefficient in the formula for calculating the number of units put into operation, so as to reduce the system oscillation caused by changes in total demand.

[0027] The scheme of the present invention is described in detail below in conjunction with the accompanying drawings and embodiments.

[0028] Example

[0029] The control method for loading a multi-machine cascade system unit provided in this embodiment includes the following implementation process:

[0030] For the loading process when the system is put into operation for the first time, see Figure 1 When the system puts the units into operation for the first time, the current theoretical value of the number of units put into operation is calculated through the unit input quantity algorithm; if the current theoretical value of the number of units put into operation is greater than the current number of units that can be operated in the system, the actual number of units loaded is the current number of units that can be operated in the system, otherwise, it is the current theoretical value of the number of units put into operation.

[0031] An exemplary formula for calculating the theoretical value of the current number of units put into use is as follows:

[0032]

[0033] Among them, N L is the theoretical value of the number of units put into use; T set is the set temperature; T ctr is to control the water temperature; P is the unit cooling and heating capacity coefficient; M is the number of system units; L X It is the capacity configuration coefficient, which is calculated based on the ratio of system output capacity to current actual demand capacity.

[0034] In the above formula, the capacity configuration coefficient L is innovatively introduced XFor example, the system cooling capacity is 60KW, and the user has 5 rooms with cooling demand, and each room has a demand capacity of 10KW. At this time, the system capacity configuration coefficient is 60 / 50=1.2. When the user's demand for cooling changes from the original 5 rooms to 3, the user's actual total capacity demand becomes 30KW, and the system capacity configuration system becomes 60 / 30=2. Substituting the capacity configuration coefficient parameter into the unit input quantity algorithm can effectively adjust the number of units put into operation to reduce the system oscillation caused by changes in total demand.

[0035] The theoretical value calculated by the above formula may be a non-integer. Therefore, the theoretical value of the calculated number of units to be put into use needs to be processed accordingly. Figure 2 If the calculated theoretical value is less than or equal to 0, the final number of units put into operation is 0; if the calculated theoretical value is greater than 0 and less than or equal to 1, the final number of units put into operation is 1; if the calculated theoretical value is greater than 1, the final number of units put into operation is rounded down. This processing method is also applicable to the subsequent calculation of the theoretical value of the current number of units put into operation by the unit input quantity algorithm.

[0036] During the operation of the system, if the capacity demand changes (such as the set temperature changes or the number of rooms to be cooled or heated changes) or the actual number of units loaded for the first time is the number of units that can be operated in the system, and the number of units that can be operated increases, the number of units put into operation is calculated again, see Figure 3 , by comparing the theoretical value of the number of units put into use with the actual number of operating units and the number of operable units, load control is achieved:

[0037] Theoretical value of the number of units invested N L Greater than the actual number of operating units N R In the case of L Greater than the number of operable units N EN , then according to the number of operable units N EN Determine whether to load the unit: the judgment condition is the number of runnable units N EN The actual number of operating units N R If the number of operating units N EN Greater than the actual number of operating units N R , then the system load (N EN -N R ) units, otherwise each unit is controlled by frequency control.

[0038] If the theoretical value of the number of units put into operation is N L Less than or equal to the number of operable units N EN , then the system load (N L -N R ) units. The theoretical value of the number of units invested is N LLess than or equal to the actual number of operating units N R In this case, the system controls each unit according to the frequency.

[0039] Finally, it should be noted that the above embodiments are only preferred implementations and are not intended to limit the present invention. It should be pointed out that for those skilled in the art, several modifications, equivalent replacements, improvements, etc. can be made without departing from the scope of the present invention and the scope of protection of the claims, and all of these should be included in the protection scope of the present invention.

Claims

1. A method for controlling the loading of units in a multi-machine cascade system. It is characterized in that The following steps are involved: When the system puts the unit into operation for the first time, it calculates the theoretical value of the current number of units put into operation through the unit input quantity algorithm; If the theoretical value of the current number of units put into operation is greater than the number of units that can currently be operated in the system, the actual number of units loaded is the number of units that can currently be operated in the system, otherwise, it is the theoretical value of the current number of units put into operation; When the system is in operation, if the capacity demand changes or the first actual loading quantity is the number of operable units of the system, and the current number of operable units increases, the theoretical value of the current number of unit inputs is calculated again using the unit input quantity algorithm; unit loading control is performed using the recalculated theoretical value of the current number of unit inputs, the current actual number of operating units, and the current number of operable units.

2. A method for controlling the loading of a multi-machine cascade system unit as claimed in claim 1, It is characterized in that The algorithm for calculating the number of units put into operation adopts the following formula: Among them, N L is the theoretical value of the number of units put into use; T set is the set temperature; T ctr is to control the water temperature; P is the unit cooling and heating capacity coefficient; M is the number of system units; L X It is the capacity configuration coefficient, which is calculated based on the ratio of system output capacity to current actual demand capacity.

3. A method for controlling the loading of a multi-machine cascade system unit as claimed in claim 2, It is characterized in that The unit loading control is performed by recalculating the theoretical value of the current number of units put into use, the current number of actually operating units and the current number of operable units, including: If the theoretical value of the current number of units put into operation is calculated again, N L Greater than the current actual number of operating units N R , and the theoretical value of the current number of units put into use is calculated again L Greater than or equal to the number of currently operable units N EN , and the number of currently operable units is N EN Greater than the current actual number of operating units N R , then the system load (N EN -N R ) units; If the theoretical value of the current number of units put into operation is calculated again, N L Greater than the current actual number of operating units N R , and the theoretical value of the current number of units put into use is calculated again L Less than the current number of operable units N EN , then the system load (N L -N R ) units.

4. A method for controlling the loading of a multi-machine cascade system unit as claimed in claim 2 or 3, It is characterized in that After calculating the current theoretical value of the unit input quantity through the unit input quantity algorithm, if the calculated theoretical value of the input quantity is greater than 0 and less than or equal to 1, the final theoretical value of the input quantity is 1; if the calculated theoretical value of the input quantity is greater than 1, the final theoretical value of the input quantity is obtained by rounding down.

5. A control system for loading a multi-machine cascade system unit, comprising a processor and a memory, wherein the memory stores a computer program. It is characterized in that The processor implements the steps of the method for controlling loading of a multi-machine cascade system unit as described in any one of claims 1 to 4 by executing the computer program.

6. A storage medium having a computer program stored thereon, It is characterized in that When the computer program is executed by a processor, the steps of the method for controlling loading of a multi-machine cascade system unit as described in any one of claims 1 to 4 are implemented.

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