A control method for a multi-split air conditioner based on load self-adaption and an air conditioning unit

Abstract

The application discloses a control method and air conditioning unit of a multi-connected air conditioner based on load self-adaption, relates to the technical field of air conditioner control, and solves the technical problems of frequent start and stop of the unit, room temperature fluctuation and user discomfort caused by the mismatch between output capacity and demand load, passive control mode and insufficient self-adaptive adjustment of the multi-connected air conditioner when running at night under small load. In the application, each indoor unit is independently controlled, a load self-adaptive matching algorithm is adopted, room load is calculated in real time, the matched output capacity load is generated according to the real-time load change in each room, and independent control logic is generated; the outdoor unit calculates the supply capacity according to the parameter change of each indoor unit, realizes load self-adaptive adjustment based on the combination control of the compressor frequency and the fan rotating speed, and realizes the real-time supply-demand matching of the load in each room by the real-time matching and automatic optimization iteration of the output capacity of the outdoor unit and the room load without increasing hardware.

Description

Technical Field

[0001] This invention relates to the field of air conditioning control technology, specifically to a control method and air conditioning unit for a multi-split air conditioner based on load adaptation. Background Technology

[0002] Multi-split air conditioners have diverse usage scenarios in actual operation. Especially when running at low load at night, their output capacity may far exceed the room's demand load, causing the unit to start and stop frequently, resulting in fluctuations in room temperature and causing users to feel both hot and cold, which affects their user experience.

[0003] Current technologies employ a control scheme where the outdoor unit sends control logic to the indoor unit, which then passively executes it. This approach directly results in different indoor units being unable to adaptively adjust their control based on their individual usage scenarios. Consequently, the output capacity of the indoor units is consistently mismatched with the actual load demand of the room, hindering adaptive control. Furthermore, existing technologies rely excessively on unified control from the outdoor unit, and without additional hardware, they struggle to achieve real-time load matching through control logic optimization, leading to issues such as long response times and poor matching accuracy.

[0004] Therefore, there is an urgent need for a control method for multi-split air conditioners that allows each indoor unit to be independently load-controlled and the outdoor unit to be optimized and adjusted in a multi-split mode, and that achieves load self-adaptation through control upgrades. Summary of the Invention

[0005] Addressing the shortcomings and deficiencies of existing technologies, this invention provides a control method and air conditioning unit for multi-split air conditioners based on load adaptation. This method allows each indoor unit to independently generate output capacity according to real-time load, optimizes and adjusts the outdoor unit through a load matching algorithm, and upgrades the control scheme to achieve load adaptation without adding hardware. This reduces unit start-up and shutdown, stabilizes room temperature, and eliminates fluctuations in perceived temperature.

[0006] To achieve the above objectives, the present invention provides a control method for a multi-split air conditioner based on load adaptation. The multi-split air conditioner includes an outdoor unit and multiple indoor units. Specifically, the control method includes: Each indoor unit is independently controlled and uses a load adaptive matching algorithm. It monitors and calculates the load in the room in real time, generates a matching output capacity load based on the real-time load changes in each room, and generates independent control logic. The outdoor unit calculates the supply capacity based on the parameter changes of each indoor unit, and achieves adaptive load adjustment based on the combination control of compressor frequency and fan speed. Through real-time matching and automatic optimization iteration between the output capacity of the outdoor unit and the room load, it can achieve real-time supply and demand matching of the load in each room without adding hardware.

[0007] Preferably, the load adaptive matching algorithm includes the following steps: Get the current temperature of the indoor unit in the room, compare it with the user-set temperature value, and calculate the temperature difference between the current return air temperature of the indoor unit and the user-set temperature. Based on the relationship between the temperature difference and the system's preset threshold A, the system dynamically switches between rapid cooling mode, flexible air supply mode, and load adaptation control mode, specifically including: When the return air temperature minus the set temperature is greater than A, the system enters a rapid cooling mode. Through load matching, the system evaporation pressure is determined, and the compressor frequency and fan speed of the outdoor unit are quickly adapted to meet the evaporation temperature requirements. The outdoor expansion valve is kept fully open. The indoor electronic expansion valve is linked to all indoor unit parameters to achieve on-demand distribution of airflow to different rooms. When the return air temperature - set temperature ≤ A, the system enters the flexible air supply mode, increases the outlet air temperature, and reduces the cooling capacity by increasing the evaporation pressure, reducing the compressor frequency and fan speed. Based on the target outlet air temperature, the coil temperature F is calculated, and the opening and rate of the electronic expansion valve are dynamically adjusted to stabilize the outlet air temperature. When the return air temperature minus the set temperature is less than or equal to 1, the system enters the load adaptation control mode, calculates the room load in real time, and adjusts the output capacity of the indoor and outdoor units in conjunction with each other. It continuously optimizes and iterates the calculation of the room load requirements, so that the output capacity of the indoor unit is balanced with the room load demand, achieving no temperature fluctuations and no unit start-stop.

[0008] Preferably, in the rapid cooling mode, the airflow is dynamically allocated based on the superheat changes of each indoor unit, achieving on-demand allocation of indoor unit airflow to meet the rapid cooling needs of different rooms, including the following steps: The difference between the indoor unit return air temperature and the indoor unit inlet temperature is set as the initial superheat. Based on the initial superheat, the temperature difference between R1 and R1(AVG) is determined every N minutes. R1 is the current indoor unit temperature, and R1(AVG) is the average temperature of all indoor units that are turned on. If R1-R1(AVG) > 1℃ for 1 minute, it is determined that the cooling demand in the room is higher than the average level. Therefore, the target superheat is reduced and the opening of the electronic expansion valve is increased. If R1-R1(AVG) < -1℃ for 1 minute, it is determined that the cooling demand in the room is lower than the average level. In this case, the target superheat is increased and the electronic expansion valve is closed. If -1℃≤R1-R1(AVG)≤1℃, it is determined that the room temperature matches the average level. Therefore, the current superheat and expansion valve opening are kept unchanged to maintain stable operation.

[0009] The preferred flexible air supply mode detects the temperature in the middle of the indoor unit and raises the outlet air temperature to 15±2℃, thereby increasing the target evaporation pressure of the outdoor unit, reducing compressor frequency reduction and outdoor unit fan speed, and reducing the outdoor unit's condensation capacity. Specifically, this includes the following steps: The indoor unit calculates the temperature F of the sensor in the middle of the heat exchanger based on the target air outlet temperature, where F = 15 ± 2℃. It then adjusts the superheat according to the target coil temperature. Changes in superheat cause changes in the opening of the electronic expansion valve. During rapid adjustment, the opening adjustment rate of the electronic expansion valve is accelerated. Through the system's PID control, the air outlet temperature is stabilized at 15 ± 2℃.

[0010] The preferred load adaptation control mode achieves a balance between supply and demand by dynamically balancing the room's heat load and the indoor unit's cooling load in real time. This specifically includes the following steps: In the initial state, the initial return air load in the room is V_room × T0, and the indoor unit cooling load is V_unit × T0. After time t0 to to', N sets of time change data of return air load and coil load are obtained, and the load change curve is fitted. Combined with the demand load V_room × Ts, integral balance calculation is performed, where Ts is the ideal temperature set by the user. When the reduced heat load of the room equals the cooling load output by the indoor unit, a dynamic balance is reached, and the balance time t1 and the balance load P are obtained. At this time, the stable temperature T1 = P / V_room. If the deviation between the stable temperature T1 and the equilibrium time t1 obtained in the first iteration and the target values ​​Ts and ts exceeds the threshold, adjustment control is performed. The indoor unit's capacity output and the outdoor unit's frequency are adjusted iteratively until the integral term converges, so that the unit continues to operate in a supply-demand matching state. The temperature corresponding to the stable load of the room is determined. By calculating and comparing the room return air load curve and the indoor unit coil load curve in real time, the dynamic equilibrium point is determined, and accurate load matching is achieved.

[0011] Preferably, if the deviation between the stable temperature T1 and equilibrium time t1 obtained in the first iteration and the target values ​​Ts and ts exceeds the threshold, then adjustment control is performed; wherein, the adjustment control includes frequency correction control, indoor unit overheat control and time dimension feedback control. The frequency correction control specifically includes: using a fuzzy control scheme for unit start-up control and load transition during sudden changes; after the unit enters a stable state, the dynamic temperature equilibrium point and dynamic equilibrium time point are obtained through iterative calculation; based on the dynamic equilibrium point obtained in the first iteration, the target frequency is calculated; and the compressor frequency is dynamically adjusted to match the indoor load demand, achieving zero temperature fluctuation; the formula for calculating the target frequency is as follows: F(n)=[Σ(HP_on(k)×Kc(T))] / HP_all ×F(n-1) Where F(n) is the calculation frequency, HP_on(k) is the rated capacity of the k-th indoor unit in operation, Kc(T) is the temperature load correction factor corresponding to the indoor unit in operation, F(n-1) is the calculation frequency of the previous cycle, k is the variable corresponding to the actual operating air conditioner number, Σ(HP_on(k)×Kc(T)) is the sum of the rated capacity of all indoor units in operation multiplied by the temperature load correction factor, and HP_all is the sum of the total capacity of all indoor units in the system.

[0012] Preferably, the control of indoor unit overheating specifically includes: The formula for calculating the superheat of an electronic expansion valve is as follows: EEVSH(n) = EEVSH(n) / Kc(T); Kc(T) is the coefficient of the temperature difference. The electronic expansion valve is opened or closed based on the calculation results, and the switching rate is adjusted.

[0013] Preferably, time-dimensional feedback control specifically includes: By calculating the difference between the target expected time ts and the dynamic equilibrium time point, the absolute value of the difference reflects the change in the time dimension and is used to adjust the demand. The larger the difference, the faster the compressor frequency increase rate and the electronic expansion valve switching rate are. The time parameter feedback is used to optimize the cycle adjustment rhythm, while the temperature difference is associated with the target change trend. In the dynamic adjustment process, the response speed and temperature control accuracy are synergistically optimized.

[0014] A load-adaptive multi-split air conditioning unit adopts a load-adaptive multi-split air conditioning control method, in which multiple indoor units are connected in parallel to the outdoor unit through liquid inlet pipes and gas outlet pipes respectively. The outdoor unit includes a compressor, an expansion valve, a heat exchanger, and a fan that drives the heat exchanger. Each indoor unit includes an indoor unit expansion valve, an indoor unit heat exchanger, and indoor unit return air temperature sensor, indoor unit inlet temperature sensor, indoor unit outlet temperature sensor, and indoor unit middle temperature sensor for monitoring the indoor unit's operating status.

[0015] Preferably, it also includes a control device, which is connected to the sensors and actuators of the outdoor unit and each indoor unit via a signal connection. This control device is used to collect real-time unit operating data and output control commands to coordinate the adaptive load adjustment of the entire air conditioning unit. Specifically, it includes: User input module: used to receive user commands from a wired controller or remote control; Online input module: Acquires external environment data and remote control commands through a cloud module; Central Processing Unit: With the CPU as the core computing unit, it executes a load adaptive matching algorithm based on user input, online input, and real-time data from various sensors to dynamically adjust the operating parameters of the compressor, outdoor unit expansion valve, indoor unit expansion valve, and outdoor unit fan. Memory: As the core data processing carrier of the control device, it integrates the operating system, communication module, input / output interface and control algorithm.

[0016] The present invention provides a control method and air conditioning unit for multi-split air conditioners based on load adaptation, which has the following beneficial effects: (1) The control method of multi-split air conditioner based on load adaptation of the present invention controls each indoor unit independently, adopts load adaptive matching algorithm, dynamically adjusts output capacity in real time according to room load, generates independent control logic, and calculates supply capacity according to parameter changes of each indoor unit. Based on the combination control of compressor frequency and fan speed, load adaptive adjustment is realized. Through real-time matching and automatic optimization iteration of outdoor unit output capacity and room load, real-time supply and demand matching of load in each room is realized without increasing hardware.

[0017] Through a collaborative mechanism of independent indoor unit control and outdoor unit linkage adjustment, the system dynamically matches changes in room load, accurately balances the indoor unit's cooling load and the room's heating load, achieves real-time matching of the production valve opening, realizes load self-adaptation, and completely solves the problems of frequent unit start-stop and room temperature fluctuations during low-load operation at night, ensuring that users experience a stable and comfortable temperature without sudden changes in temperature.

[0018] (2) The multi-split air conditioning unit based on load adaptation in this invention achieves high-precision temperature control through a load adaptation control scheme, eliminating frequent start-stop and room temperature fluctuations under low load at night; based on the multi-algorithm collaboration and dynamic parameter matching of fuzzy control, PID regulation and time dimension feedback control, it quickly converges to the equilibrium point in the first iteration, significantly shortening the adjustment time, and continuously optimizing the load matching accuracy as it runs; the entire control device does not require additional hardware, and achieves flexible load adaptation control for each room through software algorithm optimization, significantly improving user comfort and system operating economy. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the multi-split air conditioning unit based on load adaptation according to the present invention; Figure 2 This is a schematic diagram of the control device in the multi-split air conditioning unit based on load adaptation according to the present invention; Figure 3 This is a flowchart of the control method for a multi-split air conditioner based on load adaptation in this invention; Figure 4 This is a schematic diagram of the time curve for dynamic load matching of the indoor unit in this invention.

[0020] In the diagram: 1. Compressor; 2. Outdoor unit expansion valve; 3. Indoor unit return air temperature sensor; 4. Indoor unit inlet temperature sensor; 5. Indoor unit outlet temperature sensor; 6. Indoor unit mid-section temperature sensor; 7. Indoor unit expansion valve; 8. Indoor unit heat exchanger; 9. Outdoor unit fan; 10. Outdoor unit heat exchanger. Detailed Implementation

[0021] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0022] like Figure 1 As shown, the multi-split air conditioning unit of the present invention includes an outdoor unit and multiple indoor units, and the multiple indoor units are connected in parallel to the outdoor unit through liquid inlet pipes and gas outlet pipes respectively. The outdoor unit includes a compressor 1, an outdoor unit expansion valve 2, an outdoor unit heat exchanger 10, and an outdoor unit fan 9 that drives the outdoor unit heat exchanger 10; each indoor unit includes an indoor unit expansion valve 7, an indoor unit heat exchanger 8, and indoor unit return air temperature sensor 3, indoor unit inlet temperature sensor 4, indoor unit outlet temperature sensor 5, and indoor unit middle temperature sensor 6 for monitoring the indoor unit's operating status.

[0023] like Figure 2 As shown, it also includes a control device. The control device communicates with the sensors and actuators of the outdoor unit and each indoor unit via signal connection. It is used to collect the unit's operating data in real time and output control commands to coordinate the adaptive load adjustment of the entire air conditioning unit. Specifically, it includes: a user input module: used to receive user commands from the wired controller or remote controller; an online input module: used to obtain external environmental data and remote control commands through the cloud module; a central processing unit: with the CPU as the core computing unit, based on user input, online input and real-time data from each sensor, it executes the load adaptive matching algorithm to dynamically adjust the operating parameters of compressor 1, outdoor unit expansion valve 2, indoor unit expansion valve 7 and outdoor unit fan 9; and a memory: serving as the core data processing carrier of the control device, integrating the operating system, communication module, input / output interface and control algorithm.

[0024] This invention presents a load-adaptive multi-split air conditioning control method. Each indoor unit is independently controlled, employing a load-adaptive matching algorithm. By real-time monitoring and calculation of room load, a matching output capacity load is generated based on the real-time load changes in each room, resulting in independent control logic. The outdoor unit calculates its supply capacity based on parameter changes of each indoor unit, using a combination of compressor frequency and fan speed control. This involves real-time matching and automatic optimization iteration between the outdoor unit's output capacity and room load. The combination of independent indoor unit control and the load-adaptive matching algorithm enables each indoor unit to generate a matching output capacity load and independent control logic based on the real-time load changes in its respective room. Simultaneously, the outdoor unit achieves adaptive load adjustment based on the combination of compressor frequency and fan speed control. Through real-time matching and automatic optimization iteration, without adding hardware, this method effectively solves the problems of frequent unit start-stop, room temperature fluctuations, and the inability to adaptively match loads between different rooms in traditional multi-split air conditioning systems during low-load operation. This improves the accuracy of load matching and enhances the user experience.

[0025] like Figure 3 As shown, the control method specifically includes the following steps: The system acquires the current temperature of the indoor unit in the room and compares it with the user-set temperature value. It then calculates the temperature difference between the current return air temperature of the indoor unit and the user-set temperature. This temperature difference forms the basis for subsequent mode switching and refined control. Based on the relationship between the temperature difference and the system's preset threshold A, it dynamically switches between rapid cooling mode, flexible air supply mode, and load adaptation control mode to adapt to different load demands. Specifically, this includes: When the return air temperature minus the set temperature exceeds A, the system enters rapid cooling mode. Through load matching, the system evaporation pressure is determined, and the compressor frequency and fan speed of the outdoor unit are quickly adapted to meet the evaporation temperature requirements. The outdoor expansion valve is kept fully open. The indoor electronic expansion valve is linked to all indoor unit parameters to achieve on-demand distribution of airflow to different rooms. The rapid cooling mode is designed to deal with situations where there is a large deviation between the room temperature and the set temperature. By maximizing cooling capacity, the room temperature is quickly reduced.

[0026] Specifically, in rapid cooling mode, the airflow is dynamically allocated based on the superheat changes of each indoor unit, achieving on-demand airflow distribution to meet the rapid cooling needs of different rooms, including: The difference between the indoor unit return air temperature and the indoor unit inlet temperature is set as the initial superheat. Based on the initial superheat, the temperature difference between R1 and R1(AVG) is determined every N minutes. R1 is the current indoor unit temperature, and R1(AVG) is the average temperature of all indoor units that are turned on.

[0027] If R1-R1(AVG) > 1℃ for 1 minute, it is determined that the cooling demand in the room is higher than the average level. Therefore, the target superheat is reduced and the opening of the electronic expansion valve is increased.

[0028] If R1-R1(AVG) < -1℃ for 1 minute, it is determined that the cooling demand in the room is lower than the average level. In this case, the target superheat is increased and the electronic expansion valve is closed.

[0029] If -1℃≤R1-R1(AVG)≤1℃, it is determined that the room temperature matches the average level. Therefore, the current superheat and expansion valve opening are kept unchanged to maintain stable operation.

[0030] The above technical solution compares the temperature of a single indoor unit with the average temperature of all operating indoor units. By considering the magnitude and duration of the deviation, the actual cooling demand of the room is determined, and the opening of the electronic expansion valve in each indoor unit is dynamically adjusted. This enables on-demand distribution of cooling capacity among different rooms in rapid cooling mode, effectively adapting to the differentiated rapid cooling needs of various rooms. This refined cooling capacity distribution mechanism significantly improves the user experience in rapid cooling mode, avoiding the problems of some rooms being too cold or cooling too slowly, while also optimizing energy efficiency.

[0031] When the return air temperature minus the set temperature is less than or equal to A, the system enters a flexible airflow mode, increasing the outlet air temperature. This is achieved by increasing the evaporator pressure, reducing the compressor frequency and fan speed to decrease cooling capacity. Based on the target outlet air temperature, the coil temperature F is calculated, and the opening and rate of the electronic expansion valve are dynamically adjusted to stabilize the outlet air temperature. Flexible airflow mode is suitable for scenarios where the room temperature is close to the set temperature but a certain amount of cooling is still needed to maintain comfort. This mode focuses on improving airflow comfort, avoiding excessive cooling, and stabilizing the outlet air temperature through precise control.

[0032] Specifically, in flexible air supply mode, by detecting the temperature in the middle of the indoor unit, the outlet air temperature is raised to 15±2℃, increasing the target evaporation pressure of the outdoor unit, reducing compressor frequency reduction and outdoor unit fan speed, and decreasing the outdoor unit's condensing capacity. This includes the following steps: the indoor unit calculates the temperature F of the sensor in the middle of the heat exchanger based on the target outlet air temperature, where F=15±2℃; the superheat is adjusted according to the target coil temperature; changes in superheat trigger changes in the opening of the electronic expansion valve; during rapid adjustment, the opening adjustment rate of the electronic expansion valve is accelerated; through the system's PID control, the outlet air temperature is stabilized at 15±2℃. Through this technical solution, in flexible air supply mode, not only are the problems of inaccurate and fluctuating outlet air temperature control solved, but also, through refined system-level and component-level collaborative control, precise matching of cooling output with the room's low-load demand is achieved, significantly improving user comfort and optimizing the unit's operating efficiency and stability.

[0033] When the return air temperature minus the set temperature is ≤1°C, the system enters load adaptation control mode. This mode is designed for situations where the room temperature is very close to the set temperature, i.e., under low or constant load. It aims to achieve extreme temperature stability, avoid frequent unit start-stop cycles, and maximize energy efficiency. When the temperature difference further decreases to 1°C or less, the system enters load adaptation control mode. The control unit continuously monitors changes in the room's heat load in real time. Based on this real-time load data, the control unit precisely coordinates the indoor and outdoor units, continuously optimizing and iteratively calculating the required room load by fine-tuning parameters such as compressor frequency, fan speed, and electronic expansion valve opening. This ensures that the cooling output capacity of the indoor unit precisely matches the actual heat load of the room, achieving temperature stability and eliminating unit start-stop cycles.

[0034] Specifically, in load adaptation control mode, the balance between supply and demand is achieved by dynamically balancing the room's heat load and the indoor unit's cooling load in real time. This includes the following steps: like Figure 4 As shown, the horizontal axis represents the indoor unit's cooling mode operating time, and the vertical axis represents the temperature × volume value. Since the load depends on temperature, airflow, and time, load changes can be simply represented by the product of room volume, indoor unit airflow, and temperature. Curves A and B are the estimated load-time curves, respectively. Curve A is the room return air load curve, and curve B is the indoor unit R1 coil load curve. V_room refers to the room volume parameter, which is pre-filled using aggregated big data. During subsequent machine learning calculations and verification, if the adjustment time is too long and the actual return air temperature is high or low, the constant will be determined to be too large or too small and adaptively adjusted. V_machine is the airflow parameter (m³ / s) for the corresponding machine setting. Ts and ts correspond to the user-set desired ideal temperature and the time required to achieve the desired temperature, respectively. The wired controller will display the Ts and ts parameters in real time and can perform internal controls in advance based on user habits and previous settings.

[0035] Calculation process: In the initial state, the initial return air load in the room is V_room × T0, and the indoor unit cooling load is V_unit × T0. N sets of time-varying data on the return air load and coil load are obtained over time t0→to'. Load variation curves are fitted, and the trends of curves A and B are determined. Integral balance calculations are performed using the demand load V_room × Ts, where Ts is the user-set ideal temperature. When the reduced heat load in the room equals the cooling load output by the indoor unit, dynamic balance is achieved, yielding the balance time t1 and the balance load P. At this point, the stable temperature T1 achievable in the room can be calculated by dividing the balance load P by the room volume V_room.

[0036] If the stable temperature T1 and equilibrium time t1 obtained in the first iteration deviate from the target values ​​Ts and ts by more than a threshold, the system needs to adjust the operating parameters to make the actual operating state closer to the target values. This adjustment can be made to parameters such as indoor unit air volume, indoor unit expansion valve opening, and outdoor unit compressor frequency. Based on the current deviation, the system iteratively adjusts the indoor unit capacity output and links the outdoor unit frequency adjustment, gradually adjusting the control parameters and recalculating and evaluating until the integral term converges. This ensures the unit continuously operates in a supply-demand matching state, determines the temperature corresponding to the room's stable load, and accurately determines the dynamic equilibrium point by calculating and comparing the room return air load curve and the indoor unit coil load curve in real time, achieving precise load matching.

[0037] If the stable temperature T1 and equilibrium time t1 obtained in the first iteration deviate from the target values ​​Ts and ts by more than the threshold, the system needs to adjust the operating parameters. The specific adjustment and control process is as follows: 1) Frequency correction control: By adjusting the compressor's operating frequency, the cooling or heating output capacity of the outdoor unit is changed to ensure that the overall output of the entire multi-split system matches the total load demand of all currently operating indoor units. Specifically, this includes: A fuzzy control scheme is adopted for unit start-up control and load transition during sudden changes. After the unit enters a stable state, the dynamic temperature equilibrium point and dynamic equilibrium time point are obtained through iterative calculation. Based on the dynamic equilibrium point obtained in the first iteration, the target frequency is calculated. By dynamically adjusting the compressor frequency, the indoor load demand is matched to achieve temperature stability. The target operating frequency of the compressor in this period is equal to the sum of the product of the rated capacity of all indoor units and their corresponding correction coefficients, divided by the equivalent total load by the total rated capacity of all indoor units in the entire air conditioning system, and then multiplied by the compressor operating frequency of the previous control cycle. The formula for calculating the target frequency is as follows: F(n)=[Σ(HP_on(k)×Kc(T))] / HP_all ×F(n-1) Where F(n) is the calculation frequency, HP_on(k) is the rated capacity of the k-th indoor unit in operation, Kc(T) is the temperature load correction factor corresponding to the indoor unit in operation, and F(n-1) is the calculation frequency of the previous cycle; k is the variable representing the actual air conditioning unit number; Σ(HP_on(k)×Kc(T)) is the sum of the rated capacity of all indoor units in operation multiplied by the temperature load correction factor; HP_all is the sum of the total capacity of all indoor units in the system, representing the maximum cooling capacity that the entire multi-split system can provide, and is used as the denominator. Σ(HP_on(k)×Kc(T)) normalizes the total load demand of the currently operating indoor units and uses it as the numerator, thus obtaining a proportionality factor relative to the total system capacity, ensuring that the calculated frequency F(n) is within a reasonable range.

[0038] The target frequency is calculated by looking up the table to obtain the load correction coefficient Kc(T) of each indoor unit by the room temperature deviation ΔT1 and the room temperature deviation change correction parameter ΔPT. After summing the weighted loads of all indoor units, the target compressor frequency F(n) for this period is calculated according to the frequency iteration calculation formula. The compressor output frequency is dynamically corrected in real time to ensure that the total cooling / heating output of the system accurately matches the real-time load of all indoor units, so as to achieve a steady-state room temperature without significant fluctuations.

[0039] The table below shows the coefficients of the temperature difference Kc(T) corresponding to different room temperature deviations ΔT1(n) and room temperature deviation changes ΔPT under different equilibrium loads P. The equilibrium load P directly determines the equilibrium temperature T1 through the relationship T1=P / V_room, ΔT1(n)=T1(n)−T S This represents the room temperature deviation of a single indoor unit in the nth period. ΔT1(n−1) is the room temperature deviation of the previous period. ΔPT=ΔT1(n)−ΔT1(n−1) represents the change in room temperature deviation, characterizing the magnitude and direction of the temperature deviation fluctuation between the previous and subsequent periods.

[0040]

[0041] In the actual control process, the real-time room temperature and set temperature of each indoor unit are collected according to a fixed control cycle. The current room temperature deviation ΔT1(n) and the room temperature deviation change ΔPT of each indoor unit are calculated one by one, and the corresponding load correction coefficient Kc(T) is obtained by looking up the table. The rated capacity of each indoor unit is multiplied by its corresponding correction coefficient, and all the product results are summed to complete the weighted summary of the indoor unit loads and obtain the equivalent total load of the system after room temperature correction.

[0042] The equivalent total load is compared to the rated total capacity of all indoor units in the system. Combined with the compressor operating frequency of the previous cycle, the target operating frequency of the compressor in the current cycle is calculated using the frequency calculation formula. The controller adjusts the compressor output speed according to the calculated target frequency to match the compressor output capacity with the comprehensive temperature control load requirements of all operating indoor units. After each control cycle is completed, the current room temperature deviation data is cached as the deviation parameter of the previous cycle for the next cycle. This iterative process completes the dynamic frequency correction for the entire cycle.

[0043] Specifically, when ΔPT=0, it only indicates that the current temperature deviation is consistent with the previous cycle, not that the room has no load demand. At this time, the room still has an actual heat load consisting of indoor and outdoor temperature difference, heat transfer from the building envelope, heat dissipation from appliances, and human activities; it's just that the room's required load and the air conditioner's cooling output are in a relatively balanced state. When ΔPT<0, it indicates that the temperature deviation is decreasing, meaning that the current room's heat load demand is decreasing, and the air conditioner's cooling output is already greater than the room's actual demand. To avoid overcooling, prevent energy waste, and ensure stable temperature, a smaller coefficient value should be selected at this time. This causes the compressor frequency, fan speed, and expansion valve opening to decrease accordingly, reducing the system's output capacity and allowing the air conditioner's cooling output to rematch the room's reduced load demand.

[0044] Through the aforementioned control method, in load adaptation control mode, the load weight can be adjusted differently according to the actual temperature deviation of each room. Rooms with higher room temperatures correspond to a larger correction coefficient, increasing the system's equivalent load to raise the compressor's operating frequency and increase cooling output; rooms with lower room temperatures correspond to a smaller correction coefficient, reducing the equivalent load by lowering the compressor's frequency and reducing output power. At the same time, by predicting temperature rise and fall trends based on room temperature deviation changes, the frequency is adjusted in advance. After continuous iterative adjustment, the temperature of each room can be stably maintained near the set value, eliminating temperature fluctuation problems.

[0045] 2) The control of indoor unit overheating specifically includes: During the unit load adaptation control process, the calculated superheat of the indoor unit's electronic expansion valve is corrected using the temperature difference coefficient Kc(T). The corrected superheat then controls the opening and closing of the electronic expansion valve and its adjustment rate, achieving precise on-demand refrigerant flow distribution for each indoor unit. The superheat correction calculation formula is as follows: EEVSH(n) = EEVSH0 / Kc(T); Where EEVSH(n) is the superheat after coefficient correction, EEVSH0 is the original superheat, and Kc(T) is the coefficient of the temperature difference.

[0046] After completing the superheat correction calculation, the system controls the opening and closing state and operating rate of the electronic expansion valve through EEVSH(n). The specific control logic can employ interval comparison control: a target superheat range is pre-defined. When the corrected superheat is higher than the upper limit of the range, the electronic expansion valve is opened wider to increase the refrigerant flow and reduce the superheat. When the corrected superheat is lower than the lower limit of the range, the electronic expansion valve is closed to reduce refrigerant input and increase the superheat. The greater the deviation between the superheat and the target value, the faster the opening and closing rate of the electronic expansion valve. Alternatively, a PID closed-loop control mode can be used, with the target superheat as the setpoint and the corrected EEVSH(n) as the feedback input. The PID controller outputs the electronic expansion valve opening control value, and the PID tuning parameters synchronously limit the valve opening and closing rate, achieving smooth and precise throttling control.

[0047] By synchronously controlling the compressor frequency and adjusting the superheat of individual indoor units using a correction coefficient Kc(T), the superheat value is adjusted according to the load differences in each room. Indoor units with higher loads have a higher superheat after coefficient conversion, and the electronic expansion valve actively increases its opening to ensure refrigerant supply. Indoor units with lower loads have a lower superheat, and the valve actively closes to reduce excessive refrigerant delivery. This control method breaks away from the traditional, crude control mode of uniform superheat calculation and uniform throttling. Each indoor unit can match its own load to obtain an appropriate refrigerant flow, eliminating the phenomenon of excess or insufficient cooling capacity, optimizing the overall unit's supply and demand load balance, and, in conjunction with compressor frequency linkage control, ultimately achieving stable and fluctuation-free temperature operation in each room.

[0048] 3) Time-dimensional feedback control specifically includes: By calculating the difference between the target expected time ts and the dynamic equilibrium time point, the absolute value of the difference reflects the change in the time dimension, and the adjustment needs are made accordingly.

[0049] The larger the difference between the two time values, the greater the deviation of the actual balancing progress from the expected one. To simultaneously increase the compressor frequency rise / fall rate and the electronic expansion valve opening adjustment rate, a piecewise proportional control, fuzzy control, or adaptive PID method can be used, dynamically adjusting the control step size and regulation cycle based on the difference. During control, the time difference is used to manage the overall machine adjustment rhythm and optimize the regulation cycle, while the temperature difference is used to determine the temperature deviation trend and determine the adjustment direction.

[0050] By coordinating the control of time and temperature parameters, the system can accelerate the response speed under large deviation conditions while avoiding temperature overshoot oscillations caused by excessively rapid adjustments. It balances control response speed and room temperature control accuracy, improving upon the shortcomings of frequent start-stop cycles and large room temperature fluctuations under low load conditions. It achieves adaptive and precise matching of loads for each indoor unit without requiring additional hardware, significantly enhancing user comfort and system operating economy.

[0051] The present invention relates to a control method and air conditioning unit for multi-split air conditioners based on load adaptation. Multiple indoor units are independently connected to an outdoor unit and equipped with multi-position temperature sensors. Through independent indoor unit control and a load-adaptive matching algorithm, the operating mode can be switched according to the actual room load without additional hardware. The compressor frequency, electronic expansion valve opening, and control response rate are optimized in conjunction, and the output capacity is dynamically adjusted in real time according to the room load. This accurately balances the cooling load of the indoor units and the heating load of the room. Each indoor unit independently allocates refrigerant flow and cooling output as needed, effectively improving the load imbalance drawbacks of traditional unified control of the entire unit. It also eliminates the defects of frequent start-stop operations and room temperature fluctuations during low-load nighttime operation, significantly improving the overall system load matching accuracy and temperature control stability.

[0052] Based on the above embodiments, the present invention continues to describe in detail the technical features involved therein and the functions and roles of these technical features in the present invention, so as to help those skilled in the art to fully understand the technical solution of the present invention and reproduce it.

[0053] Finally, although this specification describes embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A control method for a multi-split air conditioner based on load adaptation, characterized in that, A multi-split air conditioner includes an outdoor unit and multiple indoor units, and the control method for the multi-split air conditioner specifically includes: Each indoor unit is independently controlled and uses a load adaptive matching algorithm. By monitoring and calculating the load in the room in real time, it generates a matching output capacity load based on the real-time load changes in each room and generates independent control logic. The outdoor unit calculates the supply capacity based on the parameter changes of each indoor unit, and achieves adaptive load adjustment based on the combination control of compressor frequency and fan speed. Through real-time matching and automatic optimization iteration of the outdoor unit's output capacity with the room load, it can achieve real-time supply and demand matching of the load in each room without adding hardware.

2. The control method for a multi-split air conditioner based on load adaptation according to claim 1, characterized in that, The load adaptive matching algorithm includes the following steps: Get the current temperature of the indoor unit in the room, compare it with the user-set temperature value, and calculate the temperature difference between the current return air temperature of the indoor unit and the user-set temperature. Based on the relationship between the temperature difference and the system's preset threshold A, the system dynamically switches between rapid cooling mode, flexible air supply mode, and load adaptation control mode, specifically including: When the return air temperature minus the set temperature is greater than A, the system enters a rapid cooling mode. Through load matching, the system evaporation pressure is determined, and the compressor frequency and fan speed of the outdoor unit are quickly adapted to meet the evaporation temperature requirements. The outdoor expansion valve is controlled to be fully open. The indoor electronic expansion valve is linked to all indoor unit parameters to achieve on-demand distribution of airflow to different rooms. When the return air temperature - set temperature ≤ A, the system enters the flexible air supply mode, increases the outlet air temperature, and reduces the cooling capacity by increasing the evaporation pressure, reducing the compressor frequency and fan speed. Based on the target outlet air temperature, the coil temperature F is calculated, and the opening and rate of the electronic expansion valve are dynamically adjusted to stabilize the outlet air temperature. When the return air temperature minus the set temperature is less than or equal to 1, the system enters the load adaptation control mode, calculates the room load in real time, and adjusts the output capacity of the indoor and outdoor units in conjunction with each other. It continuously optimizes and iterates the calculation of the room load requirements, so that the output capacity of the indoor unit is balanced with the room load demand, achieving no temperature fluctuations and no unit start-stop.

3. The control method for a multi-split air conditioner based on load adaptation according to claim 2, characterized in that, In the rapid cooling mode, the airflow is dynamically allocated based on the superheat changes of each indoor unit, achieving on-demand allocation of indoor unit airflow to meet the rapid cooling needs of different rooms. This includes the following steps: The difference between the indoor unit return air temperature and the indoor unit inlet temperature is set as the initial superheat. Based on the initial superheat, the temperature difference between R1 and R1(AVG) is determined every N minutes. R1 is the current indoor unit temperature, and R1(AVG) is the average temperature of all indoor units that are turned on. If R1-R1(AVG) > 1℃ for 1 minute, it is determined that the cooling demand in the room is higher than the average level. Therefore, the target superheat is reduced and the opening of the electronic expansion valve is increased. If R1-R1(AVG) < -1℃ for 1 minute, it is determined that the cooling demand in the room is lower than the average level. In this case, the target superheat is increased and the electronic expansion valve is closed. If -1℃≤R1-R1(AVG)≤1℃, it is determined that the room temperature matches the average level. Therefore, the current superheat and expansion valve opening are kept unchanged to maintain stable operation.

4. The control method for a multi-split air conditioner based on load adaptation according to claim 2, characterized in that, The flexible air supply mode detects the temperature in the middle of the indoor unit and raises the outlet air temperature to 15±2℃, thereby increasing the target evaporation pressure of the outdoor unit, reducing compressor frequency reduction and outdoor unit fan speed, and reducing the outdoor unit's condensation capacity. Specifically, it includes the following steps: The indoor unit calculates the temperature F of the sensor in the middle of the heat exchanger based on the target air outlet temperature, where F = 15 ± 2℃. It adjusts the superheat according to the target coil temperature, and the change in superheat causes the opening of the electronic expansion valve to change. During rapid adjustment, the opening adjustment rate of the electronic expansion valve is accelerated. Through the PID regulation of the system, the air outlet temperature is stabilized at 15 ± 2℃.

5. The control method for a multi-split air conditioner based on load adaptation according to claim 2, characterized in that, The load adaptation control mode achieves a balance between supply and demand by dynamically balancing the room's heat load and the indoor unit's cooling load in real time. Specifically, it includes the following steps: In the initial state, the initial return air load in the room is V_room × T0, and the indoor unit cooling load is V_unit × T0. After time t0 to to', N sets of time change data of return air load and coil load are obtained, and the load change curve is fitted. Combined with the demand load V_room × Ts, integral balance calculation is performed, where Ts is the ideal temperature set by the user. When the reduced heat load of the room equals the cooling load output by the indoor unit, a dynamic balance is reached, and the balance time t1 and the balance load P are obtained. At this time, the stable temperature T1 = P / V_room. If the deviation between the stable temperature T1 and the equilibrium time t1 obtained in the first iteration and the target values ​​Ts and ts exceeds the threshold, adjustment control is performed. The indoor unit's capacity output and the outdoor unit's frequency are adjusted iteratively until the integral term converges, so that the unit continues to operate in a supply-demand matching state. The temperature corresponding to the stable load of the room is determined. By calculating and comparing the room return air load curve and the indoor unit coil load curve in real time, the dynamic equilibrium point is determined, and accurate load matching is achieved.

6. The control method for a multi-split air conditioner based on load adaptation according to claim 5, characterized in that, If the deviation between the stable temperature T1 and equilibrium time t1 obtained in the first iteration and the target values ​​Ts and ts exceeds the threshold, then adjustment control is performed; wherein, the adjustment control includes frequency correction control, indoor unit overheat control and time dimension feedback control. The frequency correction control specifically includes: employing a fuzzy control scheme during unit start-up control and load transition periods; after the unit enters a stable state, iterative calculations are used to obtain the dynamic temperature equilibrium point and dynamic equilibrium time point; based on the dynamic equilibrium point obtained in the first iteration, the target frequency is calculated; and by dynamically adjusting the compressor frequency to match indoor load demand, temperature fluctuation-free operation is achieved; the formula for calculating the target frequency is as follows: F(n)=[Σ(HP_on(k)×Kc(T))] / HP_all ×F(n-1) Where F(n) is the calculation frequency, HP_on(k) is the rated capacity of the k-th indoor unit in operation, Kc(T) is the correction coefficient for the temperature difference, F(n-1) is the calculation frequency of the previous cycle, k is the variable corresponding to the actual operating air conditioner number, HP_all is the sum of the total capacity of all indoor units in all systems; Σ(HP_on(k)×Kc(T)) is the sum of the rated capacity of all indoor units in actual operation multiplied by the temperature load correction coefficient.

7. The control method for a multi-split air conditioner based on load adaptation according to claim 6, characterized in that, The control of indoor unit overheat specifically includes: The formula for calculating the superheat of an electronic expansion valve is as follows: EEVSH(n) = EEVSH(n) / Kc(T); Kc(T) is the coefficient of the temperature difference. The electronic expansion valve is opened or closed based on the calculation results, and the switching rate is adjusted.

8. The control method for a multi-split air conditioner based on load adaptation according to claim 6, characterized in that, The time-dimensional feedback control specifically includes: By calculating the difference between the target expected time ts and the dynamic equilibrium time point, the absolute value of the difference reflects the change in the time dimension and is used to adjust the demand. The larger the difference, the faster the compressor frequency increase rate and the electronic expansion valve switching rate are. The time parameter feedback is used to optimize the cycle adjustment rhythm, while the temperature difference is associated with the target change trend. In the dynamic adjustment process, the response speed and temperature control accuracy are synergistically optimized.

9. A multi-split air conditioning unit based on load adaptation, characterized in that, The control method for a multi-split air conditioner based on load adaptation as described in any one of claims 1-8 is adopted, wherein multiple indoor units are connected in parallel to the outdoor unit through liquid inlet pipes and gas outlet pipes respectively; The outdoor unit includes a compressor (1), an outdoor unit expansion valve (2), an outdoor unit heat exchanger (10), and an outdoor unit fan (9) that drives the outdoor unit heat exchanger (10). Each indoor unit includes an indoor unit expansion valve (7), an indoor unit heat exchanger (8), and an indoor unit return air temperature sensor (3), an indoor unit inlet temperature sensor (4), an indoor unit outlet temperature sensor (5), and an indoor unit mid-section temperature sensor (6) for monitoring the operating status of the indoor unit.

10. A multi-split air conditioning unit based on load adaptation according to claim 9, characterized in that, It also includes a control device, which is connected to the sensors and actuators of the outdoor unit and each indoor unit via a signal connection. This control device is used to collect real-time operating data of the unit and output control commands to coordinate the adaptive load adjustment of the entire air conditioning unit. Specifically, it includes: User input module: used to receive user commands from a wired controller or remote control; Online input module: Acquires external environment data and remote control commands through a cloud module; Central Processing Unit: With the CPU as the core computing unit, it executes the load adaptive matching algorithm based on user input, online input and real-time data from various sensors to dynamically adjust the operating parameters of the compressor (1), outdoor unit expansion valve (2), indoor unit expansion valve (7) and outdoor unit fan (9); Memory: As the core data processing carrier of the control device, it integrates the operating system, communication module, input / output interface and control algorithm.

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