Control method of multi-split air conditioner based on load self-adaption and air conditioning unit

Abstract

The invention discloses a control method of a multi-split air conditioner based on load self-adaption and an air conditioning unit, and relates to the technical field of air conditioner control. The technical problems that when the multi-split air conditioner operates at small load at night, due to the fact that the output capacity is not matched with the required load, the control mode is passive, and self-adaptive adjustment is insufficient, a unit is started and stopped frequently, room temperature fluctuates, and a user feels uncomfortable are solved. Each indoor unit is independently controlled, a load self-adaptive matching algorithm is adopted, room loads are calculated through real-time monitoring, matched output capacity loads are generated according to real-time load changes in respective rooms, 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 combined control of the compressor frequency and the fan rotating speed, and automatically optimizes and iterates the room load through the real-time matching and automatic optimization of the output capacity of the outdoor unit and the room load on the premise of not increasing hardware. And real-time supply and demand matching of loads in each room is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of air-conditioning control, and in particular to a control method and an air-conditioning unit for a multi-split air-conditioner based on load adaptation. Background Art

[0002] Multi-split air conditioners have a variety of usage scenarios in actual operation. Especially when operating at low load at night, there is a problem that the output capacity is far greater than the room demand load, resulting in frequent start and stop of the unit, causing the room temperature to fluctuate, causing the user to feel the temperature to fluctuate, and affecting the user's experience.

[0003] Existing technology currently uses a control scheme where the outdoor unit sends control logic to the indoor unit, which then passively executes it. This control approach directly prevents different indoor units from adaptively adjusting and controlling according to their respective usage scenarios, resulting in a long-term mismatch between the indoor unit's output capacity and the actual room load demand, making adaptive control impossible. Because existing technology relies too heavily on centralized control by the outdoor unit and, without additional hardware, it is difficult to achieve real-time load matching through control logic optimization, resulting in long response times and poor matching accuracy.

[0004] Therefore, there is an urgent need for a control method for multi-split air conditioners that can independently control the load of each indoor unit and optimize the adjustment of the outdoor unit in a multi-split mode, and achieve load adaptation through control upgrade. Summary of the Invention

[0005] In response to the shortcomings and deficiencies in the prior art, the present invention provides a control method and air-conditioning unit based on load adaptation for a multi-split air conditioner, in which each indoor unit independently generates output capacity according to the real-time load, optimizes and adjusts the outdoor unit in conjunction with a load matching algorithm, and upgrades the control scheme to achieve a load adaptation scheme without adding hardware, thereby reducing the start and stop of the unit, stabilizing the room temperature and eliminating fluctuations in perceived temperature.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions: The present invention provides a control method for a multi-split air conditioner based on load adaptation, wherein the 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 adopts a load adaptive matching algorithm. It calculates the load in the room through real-time monitoring, generates a matching output capacity load according to the real-time load changes in each room, and generates independent control logic; The outdoor unit calculates the supply capacity according to the parameter changes of each indoor unit, and realizes adaptive load adjustment based on the combined control of compressor frequency and fan speed. Through real-time matching of the output capacity of the outdoor unit with the room load and automatic optimization iteration, 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 temperature of the current room's indoor unit, compare it with the user-set temperature value, and calculate the temperature difference between the return air temperature of the current room's indoor unit and the user-set temperature; According to the relationship between the temperature difference and the system preset threshold A, the system dynamically switches between the rapid cooling mode, flexible air supply mode, and load adaptation control mode, including: When the return air temperature minus the set temperature > A, the system enters rapid cooling mode. Through load matching, the system evaporation pressure is determined, and the outdoor unit's compressor frequency and fan speed are quickly adapted to meet the evaporation temperature requirement. The outdoor expansion valve is controlled to be fully open for cooling. The indoor electronic expansion valve is linked to all the parameters of the powered-on indoor units to achieve on-demand distribution of air flow to different rooms. When the return air temperature minus the set temperature ≤ A, the system enters the flexible air supply mode, increases the outlet air temperature, reduces the cooling capacity by increasing the evaporation pressure, and reduces the compressor frequency and fan speed. Based on the target outlet air temperature, the coil temperature F is inferred, and the electronic expansion valve opening and speed are dynamically adjusted to stabilize the outlet air temperature. When the return air temperature - set temperature ≤ 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. The required load of the room is continuously optimized and iteratively calculated to balance the output capacity of the indoor unit with the required load of the room, achieving no temperature fluctuation and no start and stop of the unit.

[0008] Preferably, in the rapid cooling mode, the flow rate is dynamically allocated according to the change of the superheat degree of each indoor unit to achieve on-demand distribution of the indoor unit flow rate and meet the rapid cooling requirements 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 powered-on indoor units. If R1-R1(AVG)>1℃ for 1 minute, it is determined that the cooling demand in the room is higher than the average level, so the target superheat is reduced and the opening of the electronic expansion valve is increased; If R1-R1(AVG) is less than -1℃ for 1 minute, it is determined that the cooling demand in the room is lower than the average level, so the target superheat is increased and the electronic expansion valve is closed; If -1℃≤R1-R1(AVG)≤1℃, it is determined that the temperature in the room matches the average level, and the current superheat and expansion valve opening are kept unchanged to maintain stable operation.

[0009] Preferably, the flexible air supply mode detects the temperature in the middle of the indoor unit, increases the air outlet temperature to 15±2°C, increases the target evaporation pressure of the outdoor unit, reduces the compressor frequency reduction and the outdoor unit fan speed, and reduces the outdoor unit condensing capacity, specifically including the following steps: The indoor unit reversely calculates the temperature F of the sensor in the middle of the heat exchanger based on the target outlet air temperature, F=15±2℃, and adjusts the superheat according to the target coil temperature. The change in superheat causes the opening of the electronic expansion valve to change. During the rapid adjustment period, the opening adjustment rate of the electronic expansion valve is accelerated, and the outlet air temperature is stabilized at 15±2℃ through the system's PID adjustment.

[0010] Preferably, the load adaptation control mode achieves a balance between supply and demand loads by dynamically balancing the room heating load and the indoor unit output cooling load in real time, specifically including the following steps: In the initial state, the return air load in the room is Vroom × T0, and the indoor unit cooling load is Vunit × T0. From t0 to to', the time variation data of N groups of return air load and coil load are obtained, and the load variation curve is fitted. The integral balance calculation is performed based on the demand load Vroom × Ts, where Ts is the ideal temperature set by the user. When the reduced heat load of the room is equal to the cooling load output by the indoor unit, dynamic equilibrium is achieved, and the equilibrium time t1 and the equilibrium load P are obtained. At this time, the stable temperature T1 = P / Vroom; If the deviation between the stable temperature T1 and the balance time t1 obtained in the first iteration and the target values ​​Ts and ts exceeds the threshold, adjustment control is performed. By iteratively adjusting the indoor unit capacity output and linking the outdoor unit frequency modulation until the integral term converges, the unit can continue to operate in a supply and demand matching state, determine the temperature corresponding to the stable load of the room, and determine the dynamic balance point by real-time calculation and comparison of the room return air load curve and the indoor unit coil load curve to achieve accurate load matching.

[0011] Preferably, 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 a threshold, adjustment control is performed; wherein the adjustment control includes frequency correction control, indoor unit superheat control, and time dimension feedback control; The frequency correction control specifically includes: using a fuzzy control scheme, after the unit enters a stable state, iteratively calculating the dynamic temperature balance point and dynamic balance time point, calculating the target frequency based on the dynamic balance point obtained in the first iteration, and dynamically adjusting the compressor frequency to match the indoor load demand to achieve temperature fluctuation. The target frequency calculation formula is as follows: F(n)=[Σ(HP_on(k)×Kc(k))] / HP_on(k)*F(n-1) Where F(n) is the calculation frequency, HP_on is the total HP of all turned-on indoor units, Kc(K) is the temperature difference coefficient, F(n-1) is the calculation frequency of the previous cycle, and k is a variable.

[0012] Preferably, controlling the superheat of the indoor unit specifically includes: Calculate the superheat of the electronic expansion valve using the following formula: EEVSH(n)=EEVSH(n) / Kc(k); Kc (K) is the coefficient of temperature difference. The electronic expansion valve is opened or closed and the switching rate is adjusted according to the calculation result.

[0013] Preferably, the time dimension 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 is used to reflect the change in the time dimension to adjust the demand; When the difference is larger, the compressor frequency increase rate and the electronic expansion valve switching adjustment rate are accelerated. The feedback of the time parameter is used to optimize the cycle adjustment rhythm, and the temperature difference is associated with the target change trend, so as to achieve coordinated optimization of response speed and temperature control accuracy during the dynamic adjustment process.

[0014] A load-adaptive multi-split air-conditioning unit adopts a load-adaptive multi-split air-conditioning control method, wherein a plurality of indoor units are connected in parallel to an outdoor unit via a liquid inlet pipe and an air outlet pipe; The outdoor unit includes a compressor, an outdoor expansion valve, an outdoor heat exchanger, and an outdoor fan that drives the outdoor heat exchanger; Each indoor unit includes an indoor expansion valve, an indoor heat exchanger, and an indoor return air temperature sensor, an indoor inlet temperature sensor, an indoor outlet temperature sensor, and an indoor middle temperature sensor for monitoring the operating status of the indoor unit.

[0015] Preferably, the system further includes a control device, which is connected to the outdoor unit and sensors and actuators of each indoor unit through a signal connection method, and is used to collect unit operation data in real time and output control instructions to coordinate the adaptive load adjustment of the entire air-conditioning unit, specifically including: User input module: used to receive user instructions from the wired controller or remote control; Online input module: obtain external environment data and remote control instructions through the 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, and dynamically adjusts 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 and output interface, and control algorithm.

[0016] The present invention provides a control method for a multi-split air conditioner based on load adaptation and an air conditioning unit, which has the following beneficial effects: (1) The control method of the multi-split air conditioner based on load adaptation of the present invention dynamically adjusts the output capacity according to the room load in real time through the independent control of the indoor unit and the load adaptation matching algorithm, accurately balances the cooling load of the indoor unit and the heating load of the room, and realizes real-time matching of the production valve opening without adding hardware, and realizes load adaptation, which completely solves the problems of frequent start-up and stop of the unit and room temperature fluctuation during low-load operation at night, ensuring that the user's body temperature is stable and comfortable without sudden changes in temperature.

[0017] The load adaptive matching algorithm dynamically switches between rapid cooling, flexible air supply, and load adaptation modes based on temperature difference thresholds. Rapid cooling mode distributes airflow on demand for rapid cooling, meeting the rapid cooling needs of different rooms. As the room temperature approaches the set point, the system gradually transitions to flexible air supply mode to increase the outlet air temperature and reduce energy consumption. The load adaptive control mode ensures temperature control accuracy through integral balance calculation and iterative adjustment, achieving precise load matching and temperature control. Simultaneously, the outdoor unit dynamically generates a combined control strategy for compressor frequency and fan speed based on indoor unit parameters, and dynamically adjusts the electronic expansion valve opening based on superheat. This allows each room to be precisely controlled based on its actual load, improving the flexibility and adaptability of the overall system.

[0018] (2) The load-adaptive multi-split air-conditioning unit in the present invention achieves high-precision temperature control through a load-adaptive control scheme, eliminating frequent start-stop and room temperature fluctuations under low load at night; based on the multi-algorithm coordination and dynamic parameter matching of fuzzy control, PID regulation and time-dimensional feedback control, it quickly converges to the equilibrium point in the first iteration, significantly shortens the adjustment time, and continuously optimizes the load matching accuracy during operation; the entire control device does not require additional hardware, and realizes flexible adaptive control of the load of each room through software algorithm optimization, significantly improving user comfort and system operation economy. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0020] In the figure: 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 middle temperature sensor; 7. Indoor unit expansion valve; 8. Indoor unit heat exchanger; 9. Outdoor unit fan; 10. Outdoor unit heat exchanger. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0022] The multi-split air-conditioning control method based on load adaptation provided by the present invention is used to control a multi-split air-conditioning unit. The multi-split air-conditioning unit includes an outdoor unit and multiple indoor units, and each indoor unit is independently controlled. A load adaptive matching algorithm is adopted to calculate the room load through real-time monitoring, generate a matching output capacity load according to the real-time load changes in each room, and generate independent control logic; the outdoor unit calculates the supply capacity according to the parameter changes of each indoor unit, and realizes load adaptive adjustment based on the combined control of the compressor frequency and the fan speed. Through real-time matching of the output capacity of the outdoor unit with the room load and automatic optimization iteration, it is possible to realize real-time supply and demand matching of the load in each room without increasing hardware.

[0023] like Figure 1 As shown, the multi-split air conditioning unit includes an outdoor unit and multiple indoor units, and the multiple indoor units are connected to the outdoor unit in parallel through liquid inlet pipes and gas outlet pipes; Among them, the outdoor unit includes a compressor 1, an outdoor expansion valve 2, an outdoor heat exchanger 10 and an outdoor fan 9 that drives the outdoor heat exchanger 10; each indoor unit includes an indoor expansion valve 7, an indoor heat exchanger 8, and an indoor return air temperature sensor 3, an indoor inlet temperature sensor 4, an indoor outlet temperature sensor 5 and an indoor middle temperature sensor 6 for monitoring the operating status of the indoor unit.

[0024] like Figure 2As shown, it also includes a control device, which communicates with the sensors and actuators of the outdoor unit and each indoor unit through a signal connection, and is used to collect the unit operation data in real time and output control instructions to coordinate the adaptive load adjustment of the entire air-conditioning unit; specifically includes: a user input module: used to receive user instructions from a wired controller or a remote controller; an online input module: obtains external environmental data and remote control instructions through a 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, executes a load adaptive matching algorithm, and dynamically adjusts the operating parameters of the compressor 1, the outdoor unit expansion valve 2, the indoor unit expansion valve 7 and the outdoor unit fan 9; a memory: as the core data processing carrier of the control device, it integrates an operating system, a communication module, an input and output interface, and a control algorithm.

[0025] Each indoor unit is independently controlled and adopts load adaptive matching algorithm. It calculates the room load through real-time monitoring, generates matching output capacity load according to the real-time load changes in each room, and generates independent control logic. The process of the entire control method is as follows: Figure 3 As shown, the specific steps include: Get the temperature of the current room's indoor unit, compare it with the user-set temperature value, and calculate the temperature difference between the return air temperature of the current room's indoor unit and the user-set temperature; According to the relationship between the temperature difference and the system preset threshold A, the system dynamically switches between the rapid cooling mode, flexible air supply mode, and load adaptation control mode, including: When the return air temperature minus the set temperature > A, the system enters rapid cooling mode. Through load matching, the system evaporation pressure is determined, and the outdoor unit's compressor frequency and fan speed are quickly adapted to meet the evaporation temperature requirement. The outdoor expansion valve is controlled to be fully open for cooling. The indoor electronic expansion valve is linked to all the parameters of the powered-on indoor units to achieve on-demand distribution of air flow to different rooms. Specifically, the flow rate is dynamically allocated according to the changes in the superheat of each indoor unit to achieve on-demand distribution of indoor unit flow rate 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 powered-on indoor units. If R1-R1(AVG)>1℃ for 1 minute, it is determined that the cooling demand in the room is higher than the average level, so the target superheat is reduced and the opening of the electronic expansion valve is increased; If R1-R1(AVG) is less than -1℃ for 1 minute, it is determined that the cooling demand in the room is lower than the average level, so the target superheat is increased and the electronic expansion valve is closed; If -1℃≤R1-R1(AVG)≤1℃, it is determined that the temperature in the room matches the average level, and the current superheat and expansion valve opening are kept unchanged to maintain stable operation.

[0026] When the return air temperature - set temperature ≤ A, the flexible air supply mode is entered, the middle temperature of the indoor unit is detected, the outlet air temperature is increased to 15±2℃, the target evaporation pressure of the outdoor unit is increased, the compressor frequency reduction and the outdoor unit fan speed are reduced, and the condensing capacity of the outdoor unit is reduced; specifically, the following steps are included: the indoor unit reversely calculates the middle sensor temperature F of the heat exchanger according to the target outlet air temperature, F=15±2℃, and adjusts the superheat according to the target coil temperature. The change in superheat causes the opening of the electronic expansion valve to change; during the rapid adjustment period, the opening adjustment rate of the electronic expansion valve is accelerated, and the outlet air temperature is stabilized at 15±2℃ through the system's PID adjustment.

[0027] When the return air temperature - set temperature ≤ 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. The required load of the room is continuously optimized and iteratively calculated to balance the output capacity of the indoor unit with the required load of the room, achieving no temperature fluctuation and no start and stop of the unit.

[0028] The supply and demand loads are balanced by dynamically balancing the room heating load and the indoor unit output cooling load in real time. The specific steps include: like Figure 4 As shown, the horizontal axis represents the indoor unit's cooling mode operating time, and the vertical axis represents the temperature multiplied by volume. Since load depends on temperature, circulating air volume, and time, load changes can be simply reflected by the product of the room volume and the indoor unit's air volume and temperature. Curves A and B represent the estimated load-time curves, curve A represents the room's return air load, and curve B represents the indoor unit's R1 coil load. Vroom refers to the room's volume parameter, which is pre-populated using big data aggregation. During subsequent machine learning calculations and verification, if the adjustment time is too long and the actual return air temperature is adjusted, the constant is determined to be excessive or insufficient, and adaptive adjustments are made. Vmachine refers to the air volume parameter (m³ / s) for the corresponding unit setting. Ts and ts represent the user's desired ideal temperature and the time to reach the desired temperature, respectively. The wired controller displays Ts and ts parameters in real time and can be configured based on user habits and previous settings, allowing for proactive internal control.

[0029] Calculation process: In the initial state, the room's return air load is Vroom × T0, and the indoor unit cooling load is Vunit × T0. From t0 to to', obtain N sets of time-varying data on return air load and coil load. Fit the load variation curves, determine the variation trends of curves A and B, and perform an integral balance calculation based on the demand load Vroom × Ts, where Ts is the ideal temperature set by the user. When the reduced heating load in the room equals the indoor unit's output cooling load, dynamic equilibrium is achieved, and the equilibrium time t1 and equilibrium load P are obtained. At this time, the stable temperature T1 = P / Vroom. If the deviation between the stable temperature T1 and the balance time t1 obtained in the first iteration and the target values ​​Ts and ts exceeds the threshold, the adjustment control is performed. By iteratively adjusting the indoor unit capacity output and linking the outdoor unit frequency modulation until the integral term converges, the unit is continuously operated in a supply and demand matching state, and the temperature corresponding to the room stable load is determined. By real-time calculation and comparison of the room return air load curve and the indoor unit coil load curve, the dynamic balance point can be accurately determined to achieve accurate load matching. The specific adjustment control process is as follows: 1) Frequency correction control specifically includes: using a fuzzy control scheme during startup control and the transition phase. After the unit enters a stable state, the dynamic temperature balance point and dynamic balance time point are obtained through iterative calculation. The target frequency is calculated based on the dynamic balance point obtained in the first iteration. The compressor frequency is dynamically adjusted to match the indoor load demand to achieve temperature fluctuation. The target frequency calculation formula is as follows: F(n)=[Σ(HP_on(k)×Kc(k))] / HP_on(k)*F(n-1) Where F(n) is the calculation frequency, HP_on is the total HP number of all turned-on indoor units, Kc(K) is the temperature difference coefficient. For the specific Kc(K), refer to Table 1. F(n-1) is the calculation frequency of the previous cycle. k is a variable.

[0030]

[0031] Table 1 Kc (K) temperature difference coefficients corresponding to different balanced loads P 2) Indoor unit superheat control specifically includes: Calculate the superheat of the electronic expansion valve using the following formula: EEVSH(n)=EEVSH(n) / Kc(k); Kc (K) is the coefficient of temperature difference. The electronic expansion valve is opened and closed, and the switching rate is adjusted according to the calculation result.

[0032] 3) Time dimension 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 is used to reflect the change in the time dimension to adjust the demand; When the difference is larger, the compressor frequency increase rate and the electronic expansion valve switching adjustment rate are accelerated. The feedback of the time parameter is used to optimize the cycle adjustment rhythm, and the temperature difference is associated with the target change trend, thereby achieving coordinated optimization of response speed and temperature control accuracy during the dynamic adjustment process.

[0033] Based on the multi-algorithm collaboration and dynamic parameter matching of fuzzy control, PID regulation and time-dimensional feedback control, it quickly converges to the equilibrium point in the first iteration, significantly shortens the adjustment time, and continuously optimizes the load matching accuracy during operation; the control device does not require new hardware, and flexible adaptive control of the load in each room is achieved through software algorithm optimization, which significantly improves user comfort and system operation economy.

[0034] The control method and air-conditioning unit of the present invention based on load adaptation of the multi-split air conditioner dynamically adjusts the output capacity in real time according to the room load through independent control of the indoor unit and load adaptation matching algorithm, accurately balances the cooling load of the indoor unit and the heating load of the room, and dynamically switches between rapid cooling, flexible air supply and load adaptation modes based on the temperature difference threshold to achieve accurate load matching and temperature control. Under the premise that the gear position of the indoor unit remains unchanged and no hardware is added, the real-time matching of the production valve opening is achieved, and the load is adaptive, which completely solves the problems of frequent start-up and shutdown of the unit and room temperature fluctuations during low-load operation at night, so that each room can be accurately controlled according to its actual load conditions, ensuring that the user's perceived temperature is stable and comfortable, without sudden changes in temperature, and improving the flexibility and adaptability of the overall system.

[0035] On the basis of the above embodiments, the present invention continues to describe in detail the technical features involved therein and the functions and roles played by the technical features in the present invention, so as to help technicians in this field fully understand the technical solutions of the present invention and reproduce them.

[0036] Finally, although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of 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 implementation methods 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. The control method of the multi-split air conditioner specifically includes: Each indoor unit is independently controlled and adopts a load adaptive matching algorithm to calculate the load in the room through real-time monitoring, generate a matching output capacity load according to the real-time load changes in each room, and generate independent control logic; The outdoor unit calculates the supply capacity according to the parameter changes of each indoor unit, and realizes adaptive load adjustment based on the combined control of the compressor frequency and the fan speed. Through real-time matching of the output capacity of the outdoor unit with the room load and automatic optimization iteration, it realizes real-time supply and demand matching of the load in each room without adding hardware.

2. The control method of 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 temperature of the current room's indoor unit, compare it with the user-set temperature value, and calculate the temperature difference between the return air temperature of the current room's indoor unit and the user-set temperature; According to the relationship between the temperature difference and the system preset threshold A, the rapid cooling mode, flexible air supply mode and load adaptation control mode are dynamically switched, specifically including: When the return air temperature - set temperature > A, the system enters the 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 for cooling. The indoor electronic expansion valve is linked to all the parameters of the indoor units to achieve on-demand distribution of flow in different rooms. When the return air temperature minus the set temperature ≤ A, the system enters the flexible air supply mode, increases the outlet air temperature, reduces the cooling capacity by increasing the evaporation pressure, and reduces the compressor frequency and fan speed. Based on the target outlet air temperature, the coil temperature F is inferred, and the electronic expansion valve opening and speed are dynamically adjusted to stabilize the outlet air temperature. When the return air temperature - set temperature ≤ 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. The required load of the room is continuously optimized and iteratively calculated to balance the output capacity of the indoor unit with the required load of the room, achieving no temperature fluctuation and no start and stop of the unit.

3. The control method of a multi-split air conditioner based on load adaptation according to claim 2, characterized in that: In the rapid cooling mode, the flow rate is dynamically allocated according to the change of the superheat degree of each indoor unit to achieve on-demand distribution of the indoor unit flow rate and meet the rapid cooling requirements 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 powered-on indoor units. If R1-R1(AVG)>1℃ for 1 minute, it is determined that the cooling demand in the room is higher than the average level, so the target superheat is reduced and the opening of the electronic expansion valve is increased; If R1-R1(AVG) is less than -1℃ for 1 minute, it is determined that the cooling demand in the room is lower than the average level, so the target superheat is increased and the electronic expansion valve is closed; If -1℃≤R1-R1(AVG)≤1℃, it is determined that the temperature in the room matches the average level, and the current superheat and expansion valve opening are kept unchanged to maintain stable operation.

4. The control method of a multi-split air conditioner based on load adaptation according to claim 2, characterized in that: The flexible air supply mode detects the middle temperature of the indoor unit, increases the outlet air temperature to 15±2°C, increases the target evaporation pressure of the outdoor unit, reduces the compressor frequency reduction and the outdoor unit fan speed, and reduces the outdoor unit condensing capacity, specifically including the following steps: The indoor unit reversely 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°C, and adjusts the superheat according to the target coil temperature. The change in superheat causes a change in the opening of the electronic expansion valve. During the rapid adjustment period, the opening adjustment rate of the electronic expansion valve is accelerated, and the outlet air temperature is stabilized at 15±2°C through the system's PID adjustment.

5. The control method of 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 loads by dynamically balancing the room heating load and the indoor unit output cooling load in real time. Specifically, it includes the following steps: In the initial state, the return air load in the room is Vroom × T0, and the indoor unit cooling load is Vunit × T0. From t0 to to', the time variation data of N groups of return air load and coil load are obtained, and the load variation curve is fitted. The integral balance calculation is performed based on the demand load Vroom × Ts, where Ts is the ideal temperature set by the user. When the reduced heat load of the room is equal to the cooling load output by the indoor unit, dynamic equilibrium is achieved, and the equilibrium time t1 and the equilibrium load P are obtained. At this time, the stable temperature T1 = P / Vroom; If the deviation between the stable temperature T1 and the balance time t1 obtained in the first iteration and the target values ​​Ts and ts exceeds the threshold, adjustment control is performed. By iteratively adjusting the indoor unit capacity output and linking the outdoor unit frequency modulation until the integral term converges, the unit can continue to operate in a supply and demand matching state, determine the temperature corresponding to the stable load of the room, and determine the dynamic balance point by real-time calculation and comparison of the room return air load curve and the indoor unit coil load curve to achieve accurate load matching.

6. The control method of 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 the equilibrium time t1 obtained in the first iteration and the target values ​​Ts and ts exceeds the threshold, adjustment control is performed; wherein the adjustment control includes frequency correction control, indoor unit superheat control and time dimension feedback control; The frequency correction control specifically includes: using a fuzzy control scheme, after the unit enters a stable state, obtaining a dynamic temperature balance point and a dynamic balance time point through iterative calculation, calculating a target frequency based on the dynamic balance point obtained in the first iteration, and dynamically adjusting the compressor frequency to match the indoor load demand to achieve a temperature without fluctuation; the target frequency calculation formula is as follows: F(n)=[Σ(HP_on(k)×Kc(k))] / HP_on(k)*F(n-1) Where F(n) is the calculation frequency, HP_on is the total HP of all turned-on indoor units, Kc(K) is the temperature difference coefficient, F(n-1) is the calculation frequency of the previous cycle, and k is a variable.

7. The control method of a multi-split air conditioner based on load adaptation according to claim 6, characterized in that: The control of the indoor unit superheat specifically includes: Calculate the superheat of the electronic expansion valve using the following formula: EEVSH(n)=EEVSH(n) / Kc(k); Kc (K) is the coefficient of temperature difference. The electronic expansion valve is opened or closed and the switching rate is adjusted according to the calculation result.

8. The control method of a multi-split air conditioner based on load adaptation according to claim 6, characterized in that: The time dimension 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 is used to reflect the change in the time dimension to adjust the demand; When the difference is larger, the compressor frequency increase rate and the electronic expansion valve switching adjustment rate are accelerated. The feedback of the time parameter is used to optimize the cycle adjustment rhythm, and the temperature difference is associated with the target change trend, so as to achieve coordinated optimization of response speed and temperature control accuracy during the dynamic adjustment process.

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

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

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