Self-adaptive frequency modulation method for water pump of air conditioning system

Abstract

The invention discloses a self-adaptive frequency modulation method for a water pump of an air conditioning system. The method comprises the following steps: S1, reading a set temperature difference of supply and return water, a real-time temperature difference of supply and return water, a real-time flow of supply and return water and a real-time frequency; s2, calculating the flow required by a water system under the set temperature difference of supply water and return water; s3, calculating the frequency change of the water pump under the set temperature difference of supply and return water; s4, setting adjustment convergence time, an initial step length and initial step length adjustment time; s5, dynamic change adjustment time is calculated, and dynamic change adjustment step length is calculated; adaptively adjusting the operation frequency of the water pump; judging whether the supply and return water set temperature difference, the supply and return water real-time temperature difference and the supply and return water real-time temperature return difference meet a convergence formula or not; and S6, self-adaptive adjustment of the operation frequency of the water pump is completed. According to the self-adaptive frequency modulation method for the water pump of the air conditioning system, the frequency of the water pump is regulated and controlled based on the temperature difference of supply water and return water, and self-adaptive regulation of the frequency of the water pump can be achieved by introducing dynamic change regulation time and dynamic change regulation step length.

Description

Technical Field

[0001] This invention belongs to the field of air conditioning system technology, specifically relating to an adaptive frequency regulation method for an air conditioning system water pump. Background Technology

[0002] In air conditioning water systems, water pumps, as core power equipment, are crucial for regulating the supply and return water flow. Currently, water pump frequency regulation mostly adopts a "fixed step size" control mode, which has significant limitations: firstly, the fixed adjustment step size leads to a lag in control response speed, making it difficult to quickly adapt to dynamic changes in system load; secondly, because it cannot dynamically adjust the frequency regulation amplitude based on the deviation between the target supply and return water temperature difference and the current supply and return water temperature difference, it easily leads to a "over-adjustment-correction" oscillation phenomenon near the target temperature difference. This inefficient regulation method not only severely weakens the stability of the air conditioning water system operation, causing fluctuations in cooling capacity, but also causes the water pump to deviate from its high-efficiency operating condition, increasing system energy consumption. Therefore, it is necessary to invent an adaptive frequency regulation method for air conditioning system water pumps to regulate pump frequency based on the supply and return water temperature difference, by introducing a dynamic adjustment time. Adjusting step size with dynamic changes This enables adaptive adjustment of the water pump frequency. Summary of the Invention

[0003] To address the aforementioned problems in the prior art, this invention provides an adaptive frequency regulation method for water pumps in air conditioning systems. This method regulates the pump frequency based on the supply and return water temperature difference, and introduces a dynamic adjustment time. Adjusting step size with dynamic changes It can achieve adaptive adjustment of the water pump frequency.

[0004] The present invention adopts the following technical solution: An adaptive frequency adjustment method for a water pump in an air conditioning system, the air conditioning system including an energy-saving control system, a water pump in a water system, a frequency converter for the water pump, a flow sensor on the water system for monitoring the supply and return water flow rates, and several temperature sensors for monitoring the supply and return water temperatures; the energy-saving control system is connected to the frequency converter, the flow sensor, and the temperature sensors; the energy-saving control system is equipped with a control module, which can be directly or indirectly connected to the frequency converter, the flow sensor, and the temperature sensors; the control module is used to control the frequency converter to adjust its frequency in a timely manner through the energy-saving control system; the adaptive frequency adjustment method includes the following steps: S1. The control module executes a read command to read the set temperature difference between the supply and return water. (i.e., target temperature difference), real-time temperature difference between supply and return water Real-time flow rate of water supply and return Real-time frequency of water pump operation ; S2. The control module executes the calculation instruction to calculate the set temperature difference between the supply and return water. Flow rate required for the drainage system The relation is: ; S3. The control module executes the calculation instruction to calculate the set temperature difference between the supply and return water. Changes in the frequency of the sewer pump The relation is: Among them, frequency (i.e., target frequency) is the frequency at which the water pump ensures a constant temperature difference between the supply and return water. The frequency that the inverter needs to be adjusted to; the frequency Temperature difference with the supply and return water set The relation is: ; S4. The control module executes the setting command to set and adjust the convergence time. Initial step size Initial step size adjustment time ; wherein, the adjustment of convergence time It is the water pump from the real-time frequency. Adjust to the frequency Time required; S5. The control module executes the calculation instruction to calculate the dynamic adjustment time. The relationship is as follows: ; Calculate the dynamic adjustment step size The relationship is as follows: In these two formulas For adaptive coefficients, , With the real-time temperature difference between the supply and return water and the real-time frequency Real-time changes; time adjusted according to the dynamic changes. and the dynamically changing adjustment step size Adjust the operating frequency of the water pump; The control module executes a judgment command to determine the set temperature difference between the supply and return water. The real-time temperature difference between the supply and return water Real-time temperature hysteresis between supply and return water Does it satisfy the following convergence formula: ; If the convergence formula is satisfied, then the real-time temperature difference between the supply and return water... The supply and return water temperature difference has been adjusted to the set value. (i.e., the target temperature difference), then the control module will stop controlling the frequency converter to adjust the frequency through the energy-saving control system in a timely manner; If the convergence formula is not satisfied, i.e. The time will continue to be adjusted based on the aforementioned dynamic changes. and the dynamically changing adjustment step size The operating frequency of the water pump is adjusted, specifically by the control module through the energy-saving control system, which adjusts the frequency of the frequency converter in a timely manner until the set temperature difference between the supply and return water is reached. The real-time temperature difference between the supply and return water Real-time temperature hysteresis between supply and return water It satisfies the convergence formula; S6. Complete the adaptive adjustment of the water pump operating frequency.

[0005] Furthermore, the real-time cooling capacity of the water system Specific heat capacity of water The real-time flow rate of the supply and return water The real-time temperature difference between the supply and return water The relation is: This relation is used to construct the mathematical model required for the process operation of the control module.

[0006] Furthermore, the same cooling capacity is provided by the water system. In this case, the real-time cooling capacity of the water system Specific heat capacity of water The flow rate The set temperature difference between the supply and return water The relation is: This relation is used to construct the mathematical model required for the process operation of the control module.

[0007] Furthermore, under the same operating conditions, the operating frequency of the water pump is directly proportional to the flow rate, therefore the frequency... The real-time frequency The flow rate The real-time flow rate of the supply and return water The real-time temperature difference between the supply and return water The set temperature difference between the supply and return water The relation is: This relation is used to construct the mathematical model required for the process operation of the control module.

[0008] Furthermore, in step S5, the dynamically changing adjustment time is employed. and the dynamically changing adjustment step size After that, the frequency changed. The frequency change The adjustment of convergence time The initial step size The initial step size adjustment time and the adaptive coefficient The relation is: This relation is used to construct the mathematical model required for the process operation of the control module.

[0009] Furthermore, during the actual adjustment of the water pump frequency, the dynamically changing frequency is... Continuously approaching the frequency change ,Right now ; In conjunction with step S3 Through the frequency change Construct the adaptive coefficients The real-time temperature difference between the supply and return water The real-time frequency The relationship between them satisfies the following equation: Finally, let the adaptive coefficients... This relation is used to construct the mathematical model required for the process operation of the control module.

[0010] Furthermore, in step S5... , construct ,in, , Then construct the function formula so that the function formula is: u The real-time temperature difference between the supply and return water and the real-time frequency As variables, this relation is used to construct the mathematical model required for the process operations of the control module.

[0011] Furthermore, in conjunction with step S3... , the function formula The mapping is: This relation is used to construct the mathematical model required for the process operation of the control module.

[0012] In one embodiment, if initially, the real-time temperature difference between the supply and return water... Greater than the set temperature difference between supply and return water After adjustment by the adaptive frequency modulation method, the real-time temperature difference between the supply and return water... Approaching the set temperature difference between supply and return water This is achieved through frequency modulation, that is, adjusting the real-time frequency of the water pump. Increase.

[0013] In one embodiment, if initially, the real-time temperature difference between the supply and return water... Less than the set temperature difference between supply and return water After adjustment by the adaptive frequency modulation method, the real-time temperature difference between the supply and return water... Approaching the set temperature difference between supply and return water This is achieved through frequency reduction regulation, that is, adjusting the real-time frequency of the water pump. reduce.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention discloses an adaptive frequency regulation method for water pumps in an air conditioning system, which regulates the pump frequency based on the supply and return water temperature difference and introduces a dynamic adjustment time. Adjusting step size with dynamic changes This invention achieves adaptive adjustment of the water pump frequency. The dynamically changing adjustment time introduced in this invention... and dynamically changing adjustment step size Real-time temperature difference between supply and return water and real-time frequency Real-time changes. This invention provides an adaptive frequency regulation method for water pumps in an air conditioning system, adapting to the real-time temperature difference between supply and return water. Set temperature difference between supply and return water In the "initial" stage (i.e., when the target temperature difference) approaches, the control module (based on...) and The water pump frequency is adjusted by the energy-saving control system to ensure a real-time temperature difference between the supply and return water. "Quickly" approach the set temperature difference between supply and return water (i.e., target temperature difference). When the real-time temperature difference between supply and return water... "Approaching" the set temperature difference between supply and return water (i.e., target temperature difference) Dynamic adjustment time Gradually increase, and simultaneously dynamically adjust the step size. By gradually reducing the temperature, the water system is prevented from "violent oscillations" near the target temperature difference, thus achieving "refined" and stable adjustment of the water pump near the target frequency.

[0015] This invention discloses an adaptive frequency adjustment method for a water pump in an air conditioning system. The control module dynamically adjusts the operating frequency of the water pump through an energy-saving control system. In the initial stage of approaching the target temperature difference, the frequency is adjusted "rapidly," which improves the control response speed of the air conditioning water system. During the adjustment process near the target temperature difference, the control module controls the frequency converter of the water pump through the energy-saving control system, which automatically reduces the adjustment step size and increases the adjustment time, effectively avoiding the reciprocating oscillation phenomenon of "over-adjustment-reverse adjustment."

[0016] This invention provides an adaptive frequency regulation method for water pumps in air conditioning systems, which can achieve rapid dynamic matching between pump operation and system load, while enhancing the operational stability of the water system and ensuring the efficient and energy-saving operation of the air conditioning water system. Attached Figure Description

[0017] The technology of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments: Figure 1 This is a simplified diagram showing the connection relationship between the energy-saving control system and the frequency converter, flow sensor, and temperature sensor.

[0018] Figure label: 1-Energy-saving control system; 11-Control module; 2-Inverter; 3-Flow sensor; 41 - First temperature sensor; 42 - Second temperature sensor. Detailed Implementation

[0019] The following will provide a clear and complete description of the concept, specific structure, and technical effects of the present invention in conjunction with embodiments and accompanying drawings, so as to fully understand the purpose, solution, and effects of the present invention. It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The same reference numerals used throughout the accompanying drawings indicate the same or similar parts.

[0020] It should be noted that, unless otherwise specified, when a feature is referred to as "fixed" or "connected" to another feature, it can be directly fixed or connected to the other feature, or indirectly fixed or connected to the other feature. Furthermore, the descriptions of "up," "down," "left," and "right" used in this invention are only relative to the relative positional relationships of the various components of the invention in the accompanying drawings.

[0021] Reference Figure 1 An adaptive frequency adjustment method for a water pump in an air conditioning system is disclosed. The air conditioning system includes an energy-saving control system 1, a water pump in the water system, a frequency converter 2 for the water pump, a flow sensor 3 for monitoring the supply and return water flow rates, and several temperature sensors for monitoring the supply and return water temperatures. The energy-saving control system 1 is connected to the frequency converter 2, the flow sensor 3, and the temperature sensors. The energy-saving control system is equipped with a control module 11, which can be directly or indirectly connected to the frequency converter 2, the flow sensor 3, and the temperature sensors. The control module 11 is used to control the frequency converter 2 to adjust its frequency in a timely manner through the energy-saving control system. The adaptive frequency adjustment method includes the following steps: S1. The control module executes a read command to read the set temperature difference between the supply and return water. Real-time temperature difference between supply and return water Real-time flow rate of water supply and return Real-time frequency of water pump operation ; S2. The control module executes the calculation instruction to calculate the set temperature difference between the supply and return water. Flow rate required for the drainage system The relation is: ; S3. The control module executes the calculation instruction to calculate the set temperature difference between the supply and return water. Changes in the frequency of the sewer pump The relation is: Among them, frequency (i.e., target frequency) is the frequency at which the water pump ensures a constant temperature difference between the supply and return water. The frequency that the inverter needs to be adjusted to; the frequency Temperature difference with the supply and return water set The relation is: ; S4. The control module executes the setting command to set and adjust the convergence time. Initial step size Initial step size adjustment time ; wherein, the adjustment of convergence time It is the water pump from the real-time frequency. Adjust to the frequency Time required; S5. The control module executes the calculation instruction to calculate the dynamic adjustment time. The relationship is as follows: ; Calculate the dynamic adjustment step size The relationship is as follows: In these two formulas For adaptive coefficients, , With the real-time temperature difference between the supply and return water and the real-time frequency Real-time changes; time adjusted according to the dynamic changes. and the dynamically changing adjustment step size Adjust the operating frequency of the water pump; The control module executes a judgment command to determine the set temperature difference between the supply and return water. The real-time temperature difference between the supply and return water Real-time temperature hysteresis between supply and return water Does it satisfy the following convergence formula: ; If the convergence formula is satisfied, then the real-time temperature difference between the supply and return water... The supply and return water temperature difference has been adjusted to the set value. If the control module then stops controlling the frequency converter to adjust the frequency through the energy-saving control system, the control module will stop controlling the frequency converter to adjust the frequency in a timely manner. If the convergence formula is not satisfied, i.e. The time will continue to be adjusted based on the aforementioned dynamic changes. and the dynamically changing adjustment step size The operating frequency of the water pump is adjusted, specifically by the control module through the energy-saving control system, which adjusts the frequency of the frequency converter in a timely manner until the set temperature difference between the supply and return water is reached. The real-time temperature difference between the supply and return water Real-time temperature hysteresis between supply and return water It satisfies the convergence formula; S6. Complete the adaptive adjustment of the water pump operating frequency.

[0022] In one embodiment, the air conditioning water system is an existing air conditioning water system, as detailed in the prior art, and will not be repeated here. Supply and return water refers to the circulating water in the air conditioning water system; the supply and return water pipelines of the water system can be either a chilled water loop or a cooling water loop. The water pump is the core power equipment in the water system for regulating the supply and return water flow rates; the frequency converter is a component for regulating the operating frequency of the water pump; by changing the operating frequency of the water pump, the supply and return water flow rates in the water system's supply and return water pipelines can be adjusted; the energy-saving control system is connected to the frequency converter, and the control module can execute reading commands to read the real-time operating frequency of the water pump. The control module can adjust the operating frequency of the frequency converter through the energy-saving control system.

[0023] In one embodiment, two temperature sensors are provided. The first temperature sensor 41 is installed at the outlet of the water system to measure the supply temperature of the circulating water. The second temperature sensor 42 is installed at the return outlet of the water system to measure the return temperature of the circulating water. These two temperature sensors convert the collected temperature data into electrical signals, which are then transmitted to the energy-saving control system. Based on the data collected by the first temperature sensor 41 and the second temperature sensor 42, the energy-saving control system can calculate the real-time temperature difference between the supply and return water. The control module can read the real-time temperature difference between the supply and return water. .

[0024] In one embodiment, the flow sensor is installed on the supply and return water pipes of the air conditioning water system to continuously measure the flow rate of the supply and return water in the pipes; the flow sensor converts the collected flow data into an electrical signal, which is then transmitted to the energy-saving control system; the energy-saving control system can obtain the real-time flow rate of the supply and return water through the flow sensor. The control module can read the real-time flow rate of the supply and return water. .

[0025] In one embodiment, the energy-saving control system includes a controller (such as a PLC controller); the control module (such as a program module) is disposed in the controller; the controller is connected to the frequency converter, the flow sensor, and the temperature sensor; preferably, the control module has an input setting module, which allows users to preset the supply and return water temperature difference. (i.e., target temperature difference), frequency Adjusting the convergence time Initial step size Initial step size adjustment time The control module can execute read commands to read the set temperature difference between the supply and return water. The control module can execute setting commands to adjust the convergence time. Initial step size Initial step size adjustment time .

[0026] In one embodiment, the real-time cooling capacity of the water system Specific heat capacity of water The real-time flow rate of the supply and return water The real-time temperature difference between the supply and return water The relation is: This relation is used to construct the mathematical model required for the process operation of the control module.

[0027] In one embodiment, the same cooling capacity is provided by the water system. In this case, the real-time cooling capacity of the water system Specific heat capacity of water The flow rate The set temperature difference between the supply and return water The relation is: This relation is used to construct the mathematical model required for the process operation of the control module.

[0028] In one embodiment, under the same operating conditions, the operating frequency of the water pump is directly proportional to the flow rate, then the frequency... The real-time frequency The flow rate The real-time flow rate of the supply and return water The real-time temperature difference between the supply and return water The set temperature difference between the supply and return water The relation is: This relation is used to construct the mathematical model required for the process operation of the control module.

[0029] In one embodiment, in step S5, the dynamically changing adjustment time is used. and the dynamically changing adjustment step size After that, the frequency changed. The frequency change The adjustment of convergence time The initial step size The initial step size adjustment time and the adaptive coefficient The relation is: This relation is used to construct the mathematical model required for the process operation of the control module.

[0030] In one embodiment, during the actual adjustment of the water pump frequency, the dynamically changing frequency is... Continuously approaching the frequency change ,Right now ; In conjunction with step S3 Through the frequency change Construct the adaptive coefficients The real-time temperature difference between the supply and return water The real-time frequency The relationship between them satisfies the following equation: Finally, let the adaptive coefficients... This relation is used to construct the mathematical model required for the process operation of the control module.

[0031] In one embodiment, the S5 step , construct ,in, , Then construct the function formula so that the function formula is: The real-time temperature difference between the supply and return water and the real-time frequency As variables, this relation is used to construct the mathematical model required for the process operations of the control module.

[0032] In one embodiment, in conjunction with step S3 , the function formula The mapping is: This relation is used to construct the mathematical model required for the process operation of the control module.

[0033] In one embodiment, if initially, the real-time temperature difference between the supply and return water... Greater than the set temperature difference between supply and return water After adjustment by the adaptive frequency modulation method, the real-time temperature difference between the supply and return water... Approaching the set temperature difference between supply and return water (i.e., the target temperature difference), which is achieved through frequency regulation, that is, by adjusting the real-time frequency of the water pump. Increase.

[0034] In one embodiment, if initially, the real-time temperature difference between the supply and return water... Less than the set temperature difference between supply and return water After adjustment by the adaptive frequency modulation method, the real-time temperature difference between the supply and return water... Approaching the set temperature difference between supply and return water (i.e., the target temperature difference), which is achieved through frequency reduction regulation, that is, adjusting the real-time frequency of the water pump. reduce.

[0035] In one embodiment, when the air conditioning system load fluctuates, the real-time temperature difference between the supply and return water of the air conditioning water system... The real-time temperature difference between supply and return water will change as things change. Deviation from design values ​​(such as the set temperature difference between supply and return water) This will directly lead to a decrease in the overall heat exchange capacity of the water system. To ensure that the water pump's operating status adapts quickly to changes in system load, this invention uses a set temperature difference between the supply and return water. Using the target temperature difference as the control benchmark, the operating frequency of the water pump is adjusted in real time. By changing the frequency, the circulation flow rate of the water system is altered, ultimately achieving the real-time temperature difference between the supply and return water. Stabilize at the set temperature difference between supply and return water Nearby, to ensure the heat exchange efficiency of the water system.

[0036] The mathematical model was established as follows: Real-time cooling capacity of air conditioning water system , can be represented as: (1); in, This is the specific heat capacity of water; Real-time flow rate of supply and return water; This refers to the real-time temperature difference between the supply and return water.

[0037] Set temperature difference for supply and return water The same cooling capacity is provided by the water system. In the following cases: (2); in, This is the specific heat capacity of water; Set a temperature difference between the supply and return water; The water system sets the temperature difference between the supply and return water. The required flow rate under the given conditions.

[0038] According to equations (1) and (2), we can obtain: (3); According to equation (3), we get: (4).

[0039] Under the same operating conditions, the operating frequency of a water pump is directly proportional to the flow rate, therefore: (5); in, This refers to the real-time operating frequency of the water pump. The water pump is used to ensure the temperature difference between the supply and return water is... The frequency that its inverter needs to be adjusted to; The water system sets the temperature difference between the supply and return water. The required flow rate under the given conditions; Real-time flow rate of supply and return water; For the real-time temperature difference between supply and return water; Set a temperature difference between the supply and return water.

[0040] According to equation (5), we get: (6); Frequency change for: (7).

[0041] Set and adjust convergence time Initial step size Initial step size adjustment time ; wherein, the adjustment of convergence time It is the water pump from the real-time frequency. Adjust to frequency The required time; the frequency change The adjustment of convergence time The initial step size The initial step size adjustment time The relationship between these four is as follows: (8); As can be seen from equation (8), if a fixed adjustment step size (i.e., initial step size) is used... ) and a fixed settling time (i.e., initial step size settling time) This can easily lead to a lag in control response speed, making it difficult to quickly adapt to dynamic changes in system load, and it can also cause delays at the target frequency. The surrounding area exhibits an oscillating phenomenon of "overshoot-correction". Therefore, this invention introduces a dynamically changing adjustment time. and dynamically changing adjustment step size ; Dynamic adjustment time Adjustment time with initial step size The relationship is: (9); in, For adaptive coefficients (Note: and (inversely proportional) Dynamic adjustment step size With initial step size The relationship is: (10); in, For adaptive coefficients (Note: and (directly proportional) Use dynamic adjustment time and dynamically changing adjustment step size After that, the frequency changed. for: (11); Dynamic adjustment step size In essence, it refers to the adjustment range of the frequency. For example, if the frequency is adjusted by 0.1Hz every 2 seconds, then... , Hz; Ideally, the frequency should change With frequency change They are equal, but in actual adjustment, only the frequency can be changed. Continuously approaching frequency change ,Right now (12), where frequency variation It is dynamic and changing.

[0042] Based on equations (12), (11), (10), (9), and (7), we obtain: (13); According to equation (13), we get: (14); (For ease of calculation) Let expression (14): (15); among which, These are adaptive coefficients; According to equation (15), we can conclude that: With the real-time temperature difference between supply and return water and real-time frequency Changes in real time.

[0043] Here, we take "real-time temperature difference between supply and return water" as an example. Greater than the set temperature difference between supply and return water Let's illustrate with an example: Initially, the real-time temperature difference between supply and return water Greater than the set temperature difference between supply and return water (Explanation) At this time, the water pump flow rate is insufficient, and frequency adjustment is required (the operating frequency of the water pump is directly proportional to the flow rate); during frequency adjustment, the real-time frequency of the water pump operation... The flow rate of the water pump gradually increases, and the real-time temperature difference between the supply and return water gradually increases. The temperature gradually decreases and gradually approaches the set temperature difference between the supply and return water. .

[0044] Continuing, we will establish a mathematical model: make (16); Again (17); in, ; Real-time temperature difference between supply and return water and the real-time frequency For variables.

[0045] During the adjustment of the water pump operating frequency, the real-time temperature difference between the supply and return water It will gradually "approach" the set temperature difference between the supply and return water. and real-time frequency It will gradually increase (condition: initial real-time temperature difference between supply and return water). Greater than the set temperature difference between supply and return water That is, the real-time temperature difference between the supply and return water. It will vary with the real-time frequency It changes with the changes.

[0046] Continuing, we establish a mathematical model. According to equation (6), we can obtain: (18); Substituting equation (18) into equation (17), we get: (19).

[0047] According to equations (19) and (16), it can be concluded that when the real-time temperature difference between the supply and return water is... As it gradually decreases, It will decrease, adaptive coefficient It will change with the real-time temperature difference between the supply and return water. The decrease is due to the decrease in temperature. (This can be understood by combining equations (9) and (10)) The advantage of this change is that it reduces the real-time temperature difference between the supply and return water. Set temperature difference between supply and return water In the "initial stage" when the target temperature difference approaches, the control module (based on) and The water pump frequency is adjusted by the energy-saving control system to ensure a real-time temperature difference between the supply and return water. "Rapidly approach" the set temperature difference between supply and return water (i.e., target temperature difference); when the real-time temperature difference between supply and return water "Approaching" the set temperature difference between supply and return water Dynamic adjustment time Gradually increase, and simultaneously dynamically adjust the step size. Gradually reduce the temperature difference to avoid exceeding the set temperature range of the supply and return water systems. The water pump experiences violent oscillations near the target temperature difference, thereby achieving precise and stable adjustment of the pump around the target frequency.

[0048] During the water pump frequency adjustment process, the control module executes judgment commands in real time to determine the real-time temperature difference between the supply and return water. Temperature difference between supply and return water The deviation, namely the "real-time temperature hysteresis of supply and return water". ”; When the supply and return water temperature difference is set Real-time temperature difference between supply and return water Real-time temperature hysteresis between supply and return water It satisfies the following convergence formula: (20); That is, it is assumed that the real-time temperature difference between supply and return water The supply and return water temperature difference has been adjusted. Then, the control module will no longer control the frequency converter to adjust the frequency through the energy-saving control system in a timely manner; When the supply and return water temperature difference is set Real-time temperature difference between supply and return water Real-time temperature hysteresis between supply and return water It does not satisfy the convergence formula, that is We will continue to adjust the time according to dynamic changes. and dynamically changing adjustment step size The operating frequency of the water pump is adjusted, specifically by the control module through the energy-saving control system, which adjusts the frequency of the frequency converter in real time until the set temperature difference between the supply and return water is reached. Real-time temperature difference between supply and return water Real-time temperature hysteresis between supply and return water It satisfies the convergence formula, that is, it satisfies equation (20).

[0049] In another embodiment, initially, the real-time temperature difference between the supply and return water... Less than the set temperature difference between supply and return water (Explanation) At this time, the water pump flow rate is too high, and frequency reduction adjustment is required (the operating frequency of the water pump is directly proportional to the flow rate); during frequency reduction, the real-time operating frequency of the water pump... The flow rate of the water pump gradually decreases, and the real-time temperature difference between the supply and return water gradually decreases. It gradually increases and gradually approaches the set temperature difference between the supply and return water. .

[0050] This invention discloses an adaptive frequency regulation method for water pumps in an air conditioning system, which regulates the pump frequency based on the supply and return water temperature difference and introduces a dynamic adjustment time. With dynamically changing adjustment step size This enables adaptive adjustment of the water pump frequency.

[0051] Other aspects of the adaptive frequency regulation method for water pumps in an air conditioning system described in this invention can be found in the prior art and will not be repeated here.

[0052] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Therefore, any modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. An adaptive frequency regulation method for a water pump in an air conditioning system, characterized in that, The air conditioning system includes an energy-saving control system, a water pump for the water system, a frequency converter for the water pump, a flow sensor on the water system for monitoring the supply and return water flow rates, and several temperature sensors for monitoring the supply and return water temperatures. The energy-saving control system is connected to the frequency converter, the flow sensor, and the temperature sensors. The energy-saving control system is equipped with a control module, which can be directly or indirectly connected to the frequency converter, the flow sensor, and the temperature sensors. The control module is used to control the frequency converter to adjust its frequency in a timely manner through the energy-saving control system. The adaptive frequency adjustment method includes the following steps: S1. The control module executes a read command to read the set temperature difference between the supply and return water. Real-time temperature difference between supply and return water Real-time flow rate of water supply and return Real-time frequency of water pump operation ; S2. The control module executes the calculation instruction to calculate the set temperature difference between the supply and return water. Flow rate required for the drainage system The relation is: ; S3. The control module executes the calculation instruction to calculate the set temperature difference between the supply and return water. Changes in the frequency of the sewer pump The relation is: Among them, frequency The water pump is used to ensure the temperature difference between the supply and return water is... The frequency that the inverter needs to be adjusted to; the frequency Temperature difference with the supply and return water set The relation is: ; S4. The control module executes the setting command to set and adjust the convergence time. Initial step size Initial step size adjustment time ; wherein, the adjustment of convergence time It is the water pump from the real-time frequency. Adjust to the frequency Time required; S5. The control module executes the calculation instruction to calculate the dynamic adjustment time. The relationship is as follows: ; Calculate the dynamic adjustment step size The relationship is as follows: In these two formulas For adaptive coefficients, , With the real-time temperature difference between the supply and return water and the real-time frequency Real-time changes; time adjusted according to the dynamic changes. and the dynamically changing adjustment step size Adjust the operating frequency of the water pump; The control module executes a judgment command to determine the set temperature difference between the supply and return water. The real-time temperature difference between the supply and return water Real-time temperature hysteresis between supply and return water Does it satisfy the following convergence formula: ； If the convergence formula is satisfied, then the real-time temperature difference between the supply and return water... The supply and return water temperature difference has been adjusted to the set value. If the control module then stops controlling the frequency converter to adjust the frequency through the energy-saving control system, the control module will stop controlling the frequency converter to adjust the frequency in a timely manner. If the convergence formula is not satisfied, i.e. The time will continue to be adjusted based on the aforementioned dynamic changes. and the dynamically changing adjustment step size The operating frequency of the water pump is adjusted, specifically by the control module through the energy-saving control system, which adjusts the frequency of the frequency converter in a timely manner until the set temperature difference between the supply and return water is reached. The real-time temperature difference between the supply and return water Real-time temperature hysteresis between supply and return water It satisfies the convergence formula; S6. Complete the adaptive adjustment of the water pump operating frequency.

2. The adaptive frequency regulation method for an air conditioning system water pump according to claim 1, characterized in that, Real-time cooling capacity of the water system Specific heat capacity of water The real-time flow rate of the supply and return water The real-time temperature difference between the supply and return water The relation is: This relation is used to construct the mathematical model required for the process operation of the control module.

3. The adaptive frequency regulation method for an air conditioning system water pump according to claim 2, characterized in that, The same cooling capacity is provided by the water system. In this case, the real-time cooling capacity of the water system Specific heat capacity of water The flow rate The set temperature difference between the supply and return water The relation is: This relation is used to construct the mathematical model required for the process operation of the control module.

4. The adaptive frequency regulation method for an air conditioning system water pump according to claim 1, characterized in that, Under the same operating conditions, the operating frequency of a water pump is directly proportional to the flow rate, then the frequency... The real-time frequency The flow rate The real-time flow rate of the supply and return water The real-time temperature difference between the supply and return water The set temperature difference between the supply and return water The relation is: This relation is used to construct the mathematical model required for the process operation of the control module.

5. The adaptive frequency regulation method for an air conditioning system water pump according to claim 1, characterized in that, In step S5, the dynamic adjustment time is used. and the dynamically changing adjustment step size After that, the frequency changed. The frequency change The adjustment of convergence time The initial step size The initial step size adjustment time and the adaptive coefficient The relation is: This relation is used to construct the mathematical model required for the process operation of the control module.

6. The adaptive frequency regulation method for an air conditioning system water pump according to claim 5, characterized in that, In the actual adjustment process of the water pump frequency, the dynamically changing frequency is... Continuously approaching the frequency change ,Right now ; In conjunction with step S3 Through the frequency change Construct the adaptive coefficients The real-time temperature difference between the supply and return water The real-time frequency The relationship between them satisfies the following equation: Finally, let the adaptive coefficients... This relation is used to construct the mathematical model required for the process operation of the control module.

7. The adaptive frequency regulation method for an air conditioning system water pump according to claim 1, characterized in that, In step S5 , construct ,in, , Then construct the function formula so that the function formula is: The real-time temperature difference between the supply and return water and the real-time frequency As variables, this relation is used to construct the mathematical model required for the process operations of the control module.

8. The adaptive frequency regulation method for an air conditioning system water pump according to claim 7, characterized in that, In conjunction with step S3 , the function formula The mapping is: This relation is used to construct the mathematical model required for the process operation of the control module.

9. An adaptive frequency regulation method for an air conditioning system water pump according to any one of claims 1 to 8, characterized in that, If initially, the real-time temperature difference between the supply and return water Greater than the set temperature difference between supply and return water After adjustment by the adaptive frequency modulation method, the real-time temperature difference between the supply and return water... Approaching the set temperature difference between supply and return water This is achieved through frequency modulation, that is, adjusting the real-time frequency of the water pump. Increase.

10. An adaptive frequency regulation method for an air conditioning system water pump according to any one of claims 1 to 8, characterized in that, If initially, the real-time temperature difference between the supply and return water Less than the set temperature difference between supply and return water After adjustment by the adaptive frequency modulation method, the real-time temperature difference between the supply and return water... Approaching the set temperature difference between supply and return water This is achieved through frequency reduction regulation, that is, adjusting the real-time frequency of the water pump. reduce.

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