High-temperature air conditioning system based on dynamic cooperative control and control method thereof

Abstract

The invention relates to the technical field of air conditioners, discloses a high-temperature air conditioning system based on dynamic cooperative control and a control method thereof, and aims to solve the technical problems that a common single-stage compression variable-frequency air conditioner is prone to overtemperature and overpressure risks of a compressor and sharp attenuation of refrigerating capacity under the extreme high-temperature working condition of 43 DEG C or above. The system comprises a single-stage refrigeration circulation loop composed of a compressor, a condenser, an electronic expansion valve and an evaporator, four types of sensors used for detecting the outdoor environment temperature, the compressor exhaust temperature and the system superheat degree and a system controller. Double safety protection is formed through double-loop design of dynamic cooperation of compressor frequency control and the electronic expansion valve, the overtemperature and overpressure risk of the compressor is fundamentally avoided, the refrigeration potential of the system at the extreme high temperature can be excavated to the maximum degree, control logic is clear, robustness is high, and the system depends on preset experimental data and a classical control algorithm, and the system is suitable for large-scale popularization and application. Engineering is easy and convenient to achieve, and the safety and use experience of the air conditioner under the high-temperature working condition are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of air conditioning technology, specifically to a high-temperature air conditioning system and its control method based on dynamic collaborative control. Background Technology

[0002] Currently, ordinary single-stage compressor inverter air conditioners face severe challenges when operating under extreme conditions where outdoor temperatures exceed 43℃ or even higher (such as 48℃, 52℃, and 60℃). The condensing temperature and pressure rise sharply, causing the compressor discharge temperature and pressure to approach or even exceed safety limits, posing risks of compressor overload, lubricant carbonization, and system damage.

[0003] Existing technologies typically employ simple compressor frequency limiting (reduced frequency operation) to ensure safety. However, this approach is rather crude, failing to finely match refrigerant flow while limiting frequency, leading to a sharp decrease in system cooling capacity and a poor user experience. Although electronic expansion valves have been applied, their control logic is mostly based on fixed superheat targets. Under extreme high-temperature conditions, they lack coordination with compressor frequency control, making it impossible to dynamically achieve optimal control at the boundary between "safety" and "performance."

[0004] Therefore, there is an urgent need in this field for an intelligent control solution that can both absolutely guarantee system safety and maximize cooling capacity under extreme high temperatures. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a high-temperature air conditioning control scheme. By establishing a dynamic collaborative control logic between the compressor frequency and the opening of the electronic expansion valve, the system can automatically and accurately operate within preset safety and performance boundaries under extreme high-temperature conditions, thereby significantly improving high-temperature cooling capacity while ensuring system reliability.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a high-temperature air conditioning system based on dynamic coordinated control, comprising a single-stage refrigeration cycle loop consisting of a compressor, a condenser, an electronic expansion valve, and an evaporator; a first sensor for detecting the outdoor ambient temperature; a second sensor for detecting the compressor exhaust temperature; and a third and a fourth sensor for detecting the system superheat, wherein the system superheat is calculated from the evaporator outlet pressure and temperature.

[0007] Preferably, the third sensor is an evaporator outlet pressure sensor, and the fourth sensor is an evaporator outlet temperature sensor; The system controller stores the security boundary model, which is a two-dimensional lookup table. The system controller is configured to calculate the superheat correction ΔSH using a proportional-integral algorithm. The system controller receives detection signals from the first sensor, the second sensor, the third sensor, and the fourth sensor, and sends control commands to the compressor and the electronic expansion valve. The electronic expansion valve adjusts its opening degree according to the PWM signal output by the system controller.

[0008] Preferably, a control method for a high-temperature air conditioning system based on dynamic cooperative control includes the following steps: S1: Establish a safety boundary model. In a laboratory environment, for multiple preset high-temperature operating points, determine the key system state parameters corresponding to the combination of compressor frequency and electronic expansion valve opening at different temperatures through experimental scanning, and draw a safety operation boundary map constrained by compressor exhaust temperature and pressure. S2: Determine the compressor frequency. The system monitors the outdoor ambient temperature in real time. Based on the safety boundary model, and according to the current outdoor ambient temperature and the preset target exhaust temperature, the system calculates and limits the current maximum allowable operating frequency of the compressor by looking up a table or fitting a formula. S3: Dynamic coordinated control of the electronic expansion valve opening, specifically including: a. Set a baseline superheat target value, which is related to the compressor frequency; b. Introduce a dynamic correction mechanism to compare the actual discharge temperature of the compressor with the target discharge temperature, and dynamically correct the basic superheat target value based on the comparison result; c. The electronic expansion valve uses the modified dynamic superheat target value as the control target, combined with the feedforward of the compressor's current operating frequency, to calculate the final opening command through a PID algorithm.

[0009] Preferably, the preset high-temperature operating points mentioned in step S1 include 35℃, 43℃, 46℃, 48℃, and 52℃.

[0010] Preferably, in step S3b, the specific rules for dynamic correction are as follows: when the actual exhaust temperature is higher than the target exhaust temperature, the superheat target value is corrected upward; when the actual exhaust temperature is lower than the target exhaust temperature and there is sufficient margin, the superheat target value is maintained or corrected downward to the basic superheat target value.

[0011] Preferably, in step S2, the maximum allowed compressor frequency is retrieved using a two-dimensional lookup table.

[0012] Preferably, in step S3b, the superheat correction amount ΔSH is calculated using a preset proportional-integral algorithm, and the dynamic superheat target value SH_target = the basic superheat target value SH_base + ΔSH.

[0013] Preferably, in step S3c, the electronic expansion valve adjusts to the target opening degree by receiving a PWM signal.

[0014] Preferably, the parameters collected by the system in real time include outdoor ambient temperature T_amb, compressor exhaust temperature T_dis, and system superheat SH.

[0015] Preferably, in step S3b, when the actual exhaust temperature deviates from the target value, the system adjusts the target superheat linearly or non-linearly.

[0016] Compared with the prior art, the present invention provides a high-temperature air conditioning system and its control method based on dynamic cooperative control, which has the following beneficial effects: 1. The high-temperature air conditioning system and its control method based on dynamic collaborative control are extremely safe: the compressor frequency is directly limited by a safety boundary model based on experimental data, and the cooling is indirectly assisted by superheat control, forming a dual protection that fundamentally avoids the risk of compressor overheating and overpressure.

[0017] 2. The high-temperature air conditioning system and its control method based on dynamic collaborative control have strong high-temperature cooling capacity: Through the "dynamic target superheat" strategy, the exhaust temperature is intelligently associated with the EXV opening degree, so that the system is no longer simply reducing the frequency to ensure safety, but actively and dynamically finding and stabilizing the optimal point on the safety boundary, thereby "squeezing" out the maximum potential cooling capacity of the system under extreme conditions.

[0018] 3. The high-temperature air conditioning system and its control method based on dynamic collaborative control are intelligent and robust: adopting a decoupling approach, the two control loops perform their respective functions while being interconnected, with clear logic, reducing the complexity of the control model, and improving the system's stability and adaptability to different operating conditions.

[0019] 4. The high-temperature air conditioning system and its control method based on dynamic collaborative control are easy to implement in engineering: the core control logic relies on data that can be obtained in advance in the laboratory (lookup table MAP) and classic PID control, which has moderate requirements for the computing power of the controller and is easy to implement and debug in the product. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0021] A high-temperature air conditioning system and its control method based on dynamic collaborative control decouples the complex multivariate control problem into a compressor frequency control loop with "ensuring safety" as the core and an electronic expansion valve control loop with "pursuing efficiency" as the core. The two loops are intelligently linked through a "dynamic target superheat" strategy to achieve collaboration.

[0022] A high-temperature air conditioning control method, characterized by comprising the following steps: S1: Establish a safety boundary model. In a laboratory environment, for multiple preset high-temperature operating points (such as 35℃, 43℃, 46℃, 48℃, 52℃), through experimental scanning, determine the key system state parameters under different temperature combinations of compressor frequency and electronic expansion valve opening, and draw a safety operating boundary map constrained by compressor exhaust temperature and pressure.

[0023] S2: Determination of compressor frequency. The system monitors the outdoor ambient temperature in real time; based on the aforementioned safety boundary model, and according to the current outdoor ambient temperature and the preset target exhaust temperature, the maximum allowable operating frequency of the compressor is calculated and limited by means of table lookup or formula fitting.

[0024] S3: Dynamic coordinated control of the electronic expansion valve opening. This step is crucial to the invention, specifically: a. Set a basic superheat target value, which can be related to the compressor frequency.

[0025] b. Introduce a dynamic correction mechanism: compare the actual exhaust temperature of the compressor with the target exhaust temperature, and dynamically correct the basic superheat target value based on the comparison result.

[0026] When the actual exhaust temperature is higher than the target exhaust temperature, the superheat target value is corrected upwards. When the actual exhaust temperature is lower than the target exhaust temperature and there is sufficient margin, the superheat target value can be maintained or lowered to the baseline target to improve performance.

[0027] c. The electronic expansion valve uses the modified dynamic superheat target value as the control target, combined with the feedforward of the compressor's current operating frequency, to calculate the final opening command through a PID algorithm.

[0028] A high-temperature air conditioning system for implementing the above method, characterized in that it comprises: A single-stage refrigeration cycle consisting of a compressor, condenser, electronic expansion valve, and evaporator; The first sensor used to detect outdoor ambient temperature; A second sensor used to detect the compressor exhaust temperature; The third and fourth sensors are used to detect system superheat (calculated from evaporator outlet pressure and temperature); And, the system controller; The system controller is configured to execute the control steps S1 to S3 described above.

[0029] When using, Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A high-temperature air conditioning system based on dynamic cooperative control, characterized in that: A single-stage refrigeration cycle loop consisting of a compressor, condenser, electronic expansion valve, and evaporator; a first sensor for detecting the outdoor ambient temperature; a second sensor for detecting the compressor discharge temperature; and third and fourth sensors for detecting the system superheat, which is calculated from the evaporator outlet pressure and temperature.

2. The high-temperature air conditioning system and its control method based on dynamic cooperative control according to claim 1, characterized in that: The third sensor is an evaporator outlet pressure sensor, and the fourth sensor is an evaporator outlet temperature sensor; The system controller stores the security boundary model, which is a two-dimensional lookup table. The system controller is configured to calculate the superheat correction ΔSH using a proportional-integral algorithm. The system controller receives detection signals from the first sensor, the second sensor, the third sensor, and the fourth sensor, and sends control commands to the compressor and the electronic expansion valve. The electronic expansion valve adjusts its opening degree according to the PWM signal output by the system controller.

3. A high-temperature air conditioning system based on dynamic collaborative control according to any one of claims 1-2, characterized in that: A control method for a high-temperature air conditioning system based on dynamic cooperative control includes the following steps: S1: Establish a safety boundary model. In a laboratory environment, for multiple preset high-temperature operating points, determine the key system state parameters corresponding to the combination of compressor frequency and electronic expansion valve opening at different temperatures through experimental scanning, and draw a safety operation boundary map constrained by compressor exhaust temperature and pressure. S2: Determine the compressor frequency. The system monitors the outdoor ambient temperature in real time. Based on the safety boundary model, and according to the current outdoor ambient temperature and the preset target exhaust temperature, the system calculates and limits the current maximum allowable operating frequency of the compressor by looking up a table or fitting a formula. S3: Dynamic coordinated control of the electronic expansion valve opening, specifically including: a. Set a baseline superheat target value, which is related to the compressor frequency; b. Introduce a dynamic correction mechanism to compare the actual discharge temperature of the compressor with the target discharge temperature, and dynamically correct the basic superheat target value based on the comparison result; c. The electronic expansion valve uses the modified dynamic superheat target value as the control target, combined with the feedforward of the compressor's current operating frequency, to calculate the final opening command through a PID algorithm.

4. The control method for a high-temperature air conditioning system based on dynamic cooperative control according to claim 3, characterized in that: The preset high-temperature operating points mentioned in step S1 include 35℃, 43℃, 46℃, 48℃, and 52℃.

5. The control method for a high-temperature air conditioning system based on dynamic cooperative control according to claim 3, characterized in that: In step S3b, the specific rules for dynamic correction are as follows: when the actual exhaust temperature is higher than the target exhaust temperature, the superheat target value is corrected upward; when the actual exhaust temperature is lower than the target exhaust temperature and there is sufficient margin, the superheat target value is maintained or corrected downward to the basic superheat target value.

6. The control method for a high-temperature air conditioning system based on dynamic cooperative control according to claim 3, characterized in that: In step S2, the maximum allowed compressor frequency is retrieved using a two-dimensional lookup table.

7. The control method for a high-temperature air conditioning system based on dynamic cooperative control according to claim 3, characterized in that: In step S3b, the superheat correction amount ΔSH is calculated using a preset proportional-integral algorithm, and the dynamic superheat target value SH_target = the basic superheat target value SH_base + ΔSH.

8. The control method for a high-temperature air conditioning system based on dynamic cooperative control according to claim 3, characterized in that: In step S3c, the electronic expansion valve adjusts to the target opening degree by receiving a PWM signal.

9. The control method for a high-temperature air conditioning system based on dynamic cooperative control according to claim 3, characterized in that: The system collects parameters in real time, including outdoor ambient temperature T_amb, compressor discharge temperature T_dis, and system superheat SH.

10. The control method for a high-temperature air conditioning system based on dynamic cooperative control according to claim 3, characterized in that: In step S3b, when the actual exhaust temperature deviates from the target value, the system adjusts the target superheat linearly or nonlinearly.