Industrial air conditioner multi-parameter adaptive control method and control system

Abstract

The application belongs to the technical field of air conditioner control, and particularly relates to a multi-parameter adaptive control method and control system for an industrial air conditioner, which comprises the following steps: obtaining real-time operation parameters of the industrial air conditioner, calculating a real-time heat load intensity index, determining an add-machine instruction or a reduce-machine instruction according to the relationship between the real-time heat load intensity index and preset upper and lower intensity threshold values and locking a candidate machine, calculating an energy efficiency attenuation coefficient of the candidate machine according to suction pressure, discharge pressure and independent operation current of the candidate machine, calculating a frequency back-off compensation value of a variable frequency compressor according to rated refrigerating capacity of the candidate machine, the energy efficiency attenuation coefficient, maximum operation frequency of the variable frequency compressor and maximum refrigerating capacity of the variable frequency compressor, executing the instruction on the candidate machine and synchronously adjusting the current operation frequency of the variable frequency compressor, so as to predict a sudden heat load impact trend in advance, restore the real physical refrigerating capacity of the equipment and keep the smooth transition of system cold source output.

Description

Technical Field

[0001] This invention relates to the field of air conditioning control technology. More specifically, this invention relates to a multi-parameter adaptive control method and control system for industrial air conditioning. Background Technology

[0002] In large industrial plants and precision machining workshops, in order to balance construction costs and the engineering requirements of precise temperature control, industrial air conditioning typically adopts a parallel unit architecture of one variable frequency compressor and multiple fixed frequency compressors. The variable frequency compressor is used for fine-tuning of cooling capacity, while the multiple fixed frequency compressors bear the basic load. When the existing control logic encounters a situation where the variable frequency compressor is running at full load and the temperature in the controlled area is still rising, it usually directly issues an instruction to start one fixed frequency compressor, while lowering the operating frequency of the variable frequency compressor to a fixed initial value. The purpose of setting a fixed lowering value is to statically offset the step impact of cooling capacity brought about by the initial start-up of the fixed frequency compressor. This control method can barely maintain the operation of the system when the thermal conditions are stable and the compressor equipment is in brand new factory condition.

[0003] However, in real industrial operating environments, the actual cooling output capacity of a fixed-frequency compressor is significantly affected by physical factors such as changes in condensing pressure, fluctuations in evaporating pressure, and mechanical wear caused by long-term operation. Its actual output physical parameters are not the fixed values ​​specified at the factory. Existing fixed-value callback logic ignores the differences in actual thermodynamic operating conditions of fixed-frequency compressors under different environments. For example, during transitional seasons or in low-temperature outdoor conditions during winter, the discharge pressure of the pipeline network decreases significantly. In this case, the actual cooling capacity of a single fixed-frequency compressor will increase substantially compared to the rated test conditions. If the system still reduces the frequency of the variable-frequency compressor according to the pre-programmed fixed values, the reduced cooling capacity of the variable-frequency compressor will be far less than the enormous cooling capacity actually output by the newly started fixed-frequency compressor. This rigid offsetting method will cause the total cooling capacity delivered to the controlled area by the unit to instantly exceed the limit. This not only forces the variable-frequency compressor to quickly shut down to avoid complete loss of indoor temperature control, causing severe frequent start-stop physical oscillations, but also directly causes violent alternating hot and cold shocks in the workshop's supply air temperature.

[0004] Furthermore, traditional air conditioning unit control methods completely ignore the energy efficiency degradation that occurs in heavy fluid equipment over extended operating time. Irreversible mechanical aging, such as internal leakage at the dynamic and static sealing surfaces of the compressor, leads to an actual cooling capacity far lower than the theoretical estimate displayed on the control panel. This static control feedback mechanism creates an unbridgeable performance gap between the compensation commands given by the central system and the actual physical output capability of the underlying equipment. Ultimately, this results in an unavoidable steady-state temperature deviation in workshop temperature control, completely failing to meet the stringent requirements of precision manufacturing industries for constant temperature environments. To address the technical problems of total cooling capacity imbalance and poor temperature control accuracy caused by the aforementioned fixed callback control, this invention provides a multi-parameter adaptive control method and control system for industrial air conditioning. Summary of the Invention

[0005] To address the technical problems of total cooling capacity imbalance and supply air temperature shock caused by the aforementioned fixed value callback logic, as well as the temperature control steady-state error caused by ignoring the mechanical degradation of the compressor's energy efficiency, this invention provides solutions in the following aspects.

[0006] In a first aspect, the present invention provides a multi-parameter adaptive control method for an industrial air conditioner, wherein the industrial air conditioner adopts a parallel unit architecture of one variable frequency compressor and multiple fixed frequency compressors, comprising: acquiring real-time operating parameters of the industrial air conditioner; calculating a real-time heat load intensity index based on the real-time operating parameters; determining a compressor addition command or a compressor reduction command based on the relationship between the real-time heat load intensity index and preset intensity threshold upper and lower limits, and locking candidate compressors from multiple fixed frequency compressors; calculating the energy efficiency attenuation coefficient of the candidate compressor based on the suction pressure, discharge pressure, and independent operating current of the candidate compressor in the real-time operating parameters of the industrial air conditioner; calculating the frequency callback compensation value of the variable frequency compressor based on the rated cooling capacity, energy efficiency attenuation coefficient, maximum operating frequency and maximum cooling capacity of the candidate compressor; executing a compressor addition command or a compressor reduction command on the candidate compressor; and synchronously adjusting the current operating frequency of the variable frequency compressor based on the frequency callback compensation value.

[0007] Preferably, the real-time operating parameters also include the real-time temperature and target temperature of the controlled area, the evaporation temperature of the industrial air conditioner, and the independent operating current of each industrial frequency compressor.

[0008] Preferably, after acquiring the real-time operating parameters of the industrial air conditioner, the adaptive control method further includes: opening a cyclic data buffer inside the programmable logic controller; and performing a moving average filter on the time series data composed of the acquired real-time operating parameters to remove high-frequency electrical noise interference and obtain smoothed real-time operating parameters.

[0009] Preferably, the step of calculating the real-time heat load intensity index based on real-time operating parameters includes: calculating the algebraic difference between the real-time temperature of the controlled area and the target temperature of the controlled area to obtain the static temperature deviation; calculating the time derivative of the evaporation temperature of the industrial air conditioner using the first-order backward difference method; converting the time derivative of the evaporation temperature into an equivalent dynamic temperature deviation using the system thermal time constant; constructing a nonlinear gain factor based on the absolute value of the static temperature deviation and the temperature control sensitivity constant; and superimposing the static temperature deviation, the equivalent dynamic temperature deviation, and the nonlinear gain factor to obtain the real-time heat load intensity index.

[0010] Preferably, the step of determining the addition or reduction command and locking candidate compressors from multiple industrial frequency compressors based on the relationship between the real-time heat load intensity index and the preset intensity threshold upper and lower limits includes: when the real-time heat load intensity index is detected to be greater than the preset intensity threshold upper limit, triggering the addition command and selecting the industrial frequency compressor with the shortest cumulative fatigue running time as the candidate compressor; when the real-time heat load intensity index is detected to be less than the preset intensity threshold lower limit, triggering the reduction command and selecting the industrial frequency compressor with the longest cumulative fatigue running time as the candidate compressor; when the addition command is triggered, collecting the independent operating current of all running industrial frequency compressors and calculating the average value as the independent operating current of the candidate compressor in the shutdown state; when the reduction command is triggered, directly obtaining the independent operating current of the candidate compressor in the running state.

[0011] Preferably, obtaining the cumulative fatigue operating time includes: capturing the electrical feedback signals of the AC contactor of the power frequency compressor engaging and disengaging to obtain the stopping time and starting time of each start-stop cycle experienced by the power frequency compressor; subtracting and summing the stopping times and starting times of all start-stop cycles experienced by the power frequency compressor to obtain the total physical operating time; multiplying the start-stop damage conversion time by the total number of start-stop cycles to obtain the transient impact wear equivalent time; and superimposing the total physical operating time and the transient impact wear equivalent time to obtain the cumulative fatigue operating time of the power frequency compressor.

[0012] Preferably, the step of calculating the energy efficiency degradation coefficient of the candidate air conditioner based on the suction pressure, exhaust pressure, and independent operating current of the candidate air conditioner includes: calculating the thermodynamic volumetric efficiency under the pipeline pressure ratio based on the clearance volume ratio of the candidate air conditioner and the isentropic index of the refrigerant gas; calculating the ratio of the cumulative fatigue operating time of the candidate air conditioner to the design life of the candidate air conditioner to obtain the long-term operating factor; calculating the ratio of the independent operating current of the candidate air conditioner to the rated current of the candidate air conditioner to obtain the power input load rate; and multiplying the thermodynamic volumetric efficiency by the rated volumetric efficiency, and then multiplying it by the long-term operating factor and the power input load rate to obtain the energy efficiency degradation coefficient of the candidate air conditioner.

[0013] Preferably, the step of calculating the frequency correction compensation value of the variable frequency compressor based on the rated cooling capacity, energy efficiency attenuation coefficient, maximum operating frequency, and maximum cooling capacity of the candidate compressor includes: multiplying the rated cooling capacity of the candidate compressor by the energy efficiency attenuation coefficient to obtain the actual effective cooling capacity of the candidate compressor; establishing an equivalent substitution relationship between the cooling capacity increment of the variable frequency compressor and the actual effective cooling capacity of the candidate compressor based on the principle of static balance of cooling capacity; establishing a positive proportional mapping relationship between the frequency correction compensation value of the variable frequency compressor, the maximum operating frequency of the variable frequency compressor, the cooling capacity increment of the variable frequency compressor, and the maximum cooling capacity of the variable frequency compressor; and solving the equivalent substitution relationship and the proportional mapping relationship simultaneously to obtain the frequency correction compensation value of the variable frequency compressor.

[0014] Preferably, the step of executing a machine addition or reduction command on the candidate machine and synchronously adjusting the current operating frequency of the variable frequency compressor according to the frequency callback compensation value includes: when a machine addition command is triggered, engaging the AC contactor to start the candidate machine and setting the target frequency of the variable frequency compressor to the algebraic difference between the current operating frequency of the variable frequency compressor and the frequency callback compensation value; when a machine reduction command is triggered, disengaging the AC contactor to stop the candidate machine and setting the target frequency of the variable frequency compressor to the algebraic sum of the current operating frequency of the variable frequency compressor and the frequency callback compensation value; when the calculated target frequency of the variable frequency compressor is lower than the minimum operating frequency of the variable frequency compressor, locking the target frequency of the variable frequency compressor to the minimum operating frequency; when the calculated target frequency of the variable frequency compressor is higher than the maximum operating frequency of the variable frequency compressor, locking the target frequency of the variable frequency compressor to the maximum frequency.

[0015] In a second aspect, the present invention provides a multi-parameter adaptive control system for industrial air conditioning, including a processor and a memory, wherein the memory stores computer program instructions, and when the computer program instructions are executed by the processor, the above-mentioned multi-parameter adaptive control method for industrial air conditioning is implemented.

[0016] By adopting the above technical solution, a computer program for the above-mentioned multi-parameter adaptive control method of industrial air conditioning is generated and stored in a memory so that it can be loaded and executed by a processor. Terminal equipment can then be made based on the memory and processor for convenient use.

[0017] The beneficial effects of this invention are as follows: 1. The static temperature deviation obtained by this invention reflects the magnitude of static cooling demand that deviates from the thermal equilibrium state in the controlled area. The product of the equivalent dynamic temperature deviation and the nonlinear gain factor reflects the potential energy of dynamic heat load mutation. The above physical quantities are superimposed to obtain the real-time heat load intensity index. Thus, before the real-time temperature in the controlled area has undergone macroscopic deterioration, the industrial air conditioner can predict the impact trend of sudden heat load based on the transient change of the underlying refrigerant evaporation rate, realizing feedforward load tracking regulation and overcoming the regulation delay and frequent start-up and shutdown problems caused by traditional hysteresis temperature control.

[0018] 2. This invention transcends the three physical dimensions of electromechanical and thermal. Based on three hidden physical phenomena—the reduction in effective refrigerant suction volume caused by high operating pressure ratio, the increase in internal leakage of sealing surfaces due to long-term mechanical wear, and the limitation of spindle power input—it comprehensively obtains the actual output loss ratio. This corrects the theoretical prediction deviation in the prior art that treats the compressor as a constant ideal refrigeration source, restores the true physical refrigeration capacity of the operating equipment under different harsh operating conditions and at different stages of its life cycle, and provides a benchmark for refrigeration capacity characterization for subsequent refrigeration source compensation actions.

[0019] 3. This invention establishes the relationship between the physical degradation state of the equipment and the frequency conversion adjustment range, so that the dynamic cooling capacity increment generated by the adjustment of the frequency conversion compressor is numerically equivalent to the actual dynamic cooling capacity output by the new start-up and shutdown candidate machine. Through this equivalent substitution relationship of cooling capacity, a smooth transition of cold source output is maintained in the dimension of physical total balance of the refrigeration system, eliminating the damage to the precision temperature stability of the controlled area caused by the step impact of the cold capacity caused by the start-up and shutdown of the giant host, and meeting the temperature control requirements of high-precision constant temperature environment. Attached Figure Description

[0020] Figure 1 This is a schematic flowchart illustrating a multi-parameter adaptive control method for industrial air conditioning according to the present invention. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0023] This invention discloses a multi-parameter adaptive control method for industrial air conditioning, referring to... Figure 1 This includes steps S1-S4: S1. Obtain the real-time operating parameters of the industrial air conditioner.

[0024] It should be noted that industrial workshops contain a large number of large electromechanical equipment, with strong electromagnetic interference and drastic fluctuations in heat load. In order to extract effective information that truly reflects the state of industrial air conditioning, this invention not only needs to standardize the data source acquisition path at the hardware physical level, but also needs to smooth the acquired multi-dimensional operating data at the software algorithm level. Since the raw data collected by the sensors is mixed with high-frequency electrical noise and instantaneous interference, the moving average filtering process can filter out high-frequency noise and interference on the hardware transmission line, prevent the system from misjudging the current thermodynamic state, and avoid unnecessary fluctuations in the underlying control commands.

[0025] Specifically, the industrial air conditioner adopts a parallel unit architecture consisting of one variable frequency compressor and multiple fixed frequency compressors. Relying on a programmable logic controller (PLC) in the industrial setting and using a specific industrial communication protocol, it reads raw signals from sensor arrays installed in the controlled area and on the industrial air conditioner in real time at a fixed sampling frequency to obtain the real-time operating parameters of the industrial air conditioner. These real-time operating parameters include: the real-time temperature of the controlled area collected by a high-precision temperature sensor. The target temperature of the controlled area is preset through the human-computer interaction panel. The suction pressure of an industrial air conditioner is acquired by a piezoresistive pressure transmitter. and the exhaust pressure of industrial air conditioners The independent operating current of each industrial frequency compressor in the operating queue is collected by a current sensor. The current operating frequency of the inverter compressor and the evaporation temperature of the industrial air conditioner are read via the communication bus. The evaporation temperature of the industrial air conditioner The suction pressure of industrial air conditioners is determined by an empirical model of refrigerant saturated vapor pressure temperature. The target temperature of the controlled region is obtained through conversion. The specific values ​​are set by the implementers through the human-machine interface panel on the industrial workshop site.

[0026] Furthermore, a circular data buffer is opened inside the programmable logic controller to perform a moving average filter on the time series data composed of the continuously collected operating parameters to remove high-frequency electrical noise interference and obtain smoothed real-time operating parameters. Subsequent calculations are strictly based on these smoothed real-time operating parameters.

[0027] The sampling frequency is set within the range of 10 Hz to 50 Hz; in this embodiment, the fixed sampling frequency is set to 20 Hz. The window length for the moving average filter... The degree of data smoothing is defined; a reasonable window length can balance noise filtering effectiveness with the system's response speed to sudden industrial heat loads. The window length for moving average filtering... The calibration method involves the implementer measuring the noise spectrum of the industrial air conditioner under both no-load and full-load conditions multiple times, and selecting the period corresponding to the fundamental noise frequency as the window length for the moving average filter. In this embodiment, the specific value of the moving average filter is determined by the window length. Setting it to 10 takes the average of the 10 most recent sampling points as the measurement value at the current moment, balancing the smoothness of filtering with the real-time performance of control.

[0028] S2. Calculate the real-time heat load intensity index based on the real-time operating parameters, determine the addition or subtraction instructions based on the relationship between the real-time heat load intensity index and the intensity threshold, and lock in the candidate machines.

[0029] It should be noted that, in order to reflect the urgent need for cooling capacity in the current controlled area, this invention constructs a calculation system that integrates static temperature deviation characteristics and dynamic evaporation temperature change characteristics and introduces a nonlinear gain mechanism. By combining static temperature deviation and equivalent dynamic temperature deviation, the industrial air conditioner can respond to the absolute difference between the real-time temperature and the target temperature of the current controlled area. At the same time, based on the transient changes in the evaporation temperature of the industrial air conditioner, it can predict the trend of sudden heat load inflow in the industrial workshop in advance, thereby realizing feedforward load tracking and regulation.

[0030] Specifically, the static cooling demand and dynamic heat load abrupt change potential energy of the controlled area are calculated separately to obtain the real-time heat load intensity index, including: First, calculate the real-time temperature of the controlled area. With the target temperature of the controlled area The difference is used to obtain the static temperature deviation. , The real-time temperature of the controlled area at the current operating moment. With the target temperature of the controlled area The algebraic difference directly reflects the magnitude of the static cooling demand that deviates from the thermal equilibrium state in the controlled region. When the real-time temperature of the controlled region... The temperature rises and exceeds the target temperature of the controlled area. At that time, static temperature deviation The simultaneous increase indicates that the air conditioning system urgently needs to mobilize more cooling capacity to eliminate heat accumulation inside the physical space.

[0031] Then, the dynamic response characteristics of the underlying refrigeration system are captured. The first-order backward difference method is used to calculate the time derivative of the smoothed industrial air conditioner evaporation temperature data sequence. Since the physical change in the industrial air conditioner evaporation temperature lags behind the controlled area temperature by thermodynamic inertia, a system thermal time constant is introduced to convert the time derivative of the evaporation temperature into an equivalent dynamic temperature deviation, thereby predicting the trend of transient heat load changes in the industrial workshop. The calculation formula is as follows: In the formula, For a moment The equivalent dynamic temperature deviation; This is the current running time; For a moment Evaporation temperature of industrial air conditioners; For a moment The time derivative of evaporation temperature; The system thermal time constant is calibrated as follows: Under a test environment with constant cooling capacity of an industrial air conditioner, record the time required for the real-time temperature of the controlled area to decay at a unit step response, and calibrate this physical time as the system thermal time constant. .

[0032] The time derivative of the evaporation temperature in this calculation formula This reflects the transient change in the refrigerant heat absorption rate inside the evaporator, multiplied by the system thermal time constant. This is converted into an equivalent temperature deviation compensation; when a sudden large heat load in an industrial workshop causes a sharp increase in the refrigerant evaporation rate, the time derivative of the evaporation temperature increases significantly, leading to an equivalent dynamic temperature deviation. The synchronous surge allows for early characterization of the high-intensity thermal load shock that the system will face before the real-time temperature in the controlled area undergoes macroscopic deterioration.

[0033] Next, in order to eliminate the interference of normal fluctuations while maintaining high sensitivity to large sudden heat loads, a nonlinear gain factor based on the absolute value of the static temperature deviation is constructed, and its calculation formula is as follows: In the formula, For a moment The nonlinear gain factor; This is the current running time; It is the base of the natural logarithm; For a moment Static temperature deviation; Indicates taking the absolute value; The temperature control sensitivity constant is calibrated as follows: the maximum temperature deviation amplitude of the industrial air conditioner under permissible physical limits is statistically analyzed and used as the temperature control sensitivity constant. .

[0034] In this calculation formula, the natural exponent term acts as a non-linear amplification factor, when the static temperature deviation... The absolute value is small and much lower than the temperature control sensitivity constant. At that time, nonlinear gain factor The output value is small to suppress erroneous control commands caused by thermal fluctuations in the normal environment; when the static temperature deviation is small... When it increases significantly, the nonlinear gain factor It increases exponentially, thereby amplifying the feedback weight of the equivalent dynamic temperature deviation in subsequent calculations.

[0035] Finally, the formulas for calculating the nonlinear gain factor and the equivalent dynamic temperature deviation are substituted into the initial equation consisting of the product of the static temperature deviation, the equivalent dynamic temperature deviation, and the nonlinear gain factor. This expansion yields the intermediate derivation formula. Subsequently, the formula for calculating the static temperature deviation is substituted into the intermediate derivation formula, replacing all static temperature deviation parameters with the real-time temperature of the controlled region. Subtract the target temperature of the controlled area The expression, after algebraic extraction and simplification, yields the final calculation formula for the real-time heat load intensity index, which is: In the formula, For a moment The real-time heat load intensity index; For a moment Real-time temperature of the controlled area; The target temperature for the controlled area; The system thermal time constant; For a moment Evaporation temperature of industrial air conditioners; For a moment The time derivative of evaporation temperature; It is the base of the natural logarithm; This is the temperature control sensitivity constant; This is the current running time; This indicates taking the absolute value.

[0036] The static arithmetic part of the formula Reflects the static cooling demand basis of the system, and the dynamic derivative part With nonlinear exponential part The product of these two factors reflects the potential energy of sudden changes in dynamic heat load. Their superposition enables immediate capture of sudden large-load cooling demands. When the real-time temperature of the controlled area is significantly higher than the target temperature of the controlled area and the evaporation temperature of the industrial air conditioner rises sharply, the real-time heat load intensity index... This will result in a geometric progression, enabling the underlying controller to quickly trigger decisions to add or remove equipment in order to meet the physical demands of thermal loads under extreme operating conditions.

[0037] Furthermore, the system monitors the device status register inside the programmable logic controller in real time: when the real-time heat load intensity index is detected to be greater than the preset intensity threshold upper limit, a machine addition command is triggered, and the industrial frequency compressor with the shortest cumulative fatigue running time is selected and locked as a candidate machine; when the real-time heat load intensity index is detected to be less than the preset intensity threshold lower limit, a machine reduction command is triggered, and the industrial frequency compressor with the longest cumulative fatigue running time is selected and locked as a candidate machine; otherwise, the closed-loop servo regulation state of the variable frequency compressor is maintained.

[0038] The method for determining the cumulative fatigue operating time of the industrial frequency compressor is as follows: The electrical feedback signals of the AC contactor of the industrial frequency compressor being engaged and disengaged are captured to obtain the stopping and starting times of each start-stop cycle experienced by the compressor. The stopping and starting times of all start-stop cycles experienced by the compressor are subtracted and summed to obtain the total physical operating time. The equivalent time of transient impact wear is obtained by multiplying the start-stop damage conversion time by the total number of start-stop cycles. The cumulative fatigue operating time of the industrial frequency compressor is obtained by superimposing the total physical operating time and the equivalent time of transient impact wear. The calibration method for the start-stop damage conversion time is as follows: The fatigue life pressure test report of the industrial frequency compressor is consulted to extract the wear amount caused to the internal bearings by a single extreme cold start. Simultaneously, the stable wear rate per unit time under rated continuous operation is extracted. The wear amount is divided by the stable wear rate to calculate the equivalent operating time of a single start-stop action, and this equivalent operating time is set as the start-stop damage conversion time.

[0039] By linearly superimposing the total physical operating time with the equivalent time of transient impact wear caused by mechanical start-stop cycles, the cumulative fatigue operating time of the industrial frequency compressor monotonically increases with the accumulation of the total number of start-stop cycles and the physical operating time of the machinery, reflecting the metal mechanical aging process of the core compression equipment.

[0040] Finally, when a machine addition command is triggered, since the candidate machine is in a stopped state, the system collects the independent operating current of all running industrial frequency compressors in the running queue and calculates the average value. This average value is used as the independent operating current of the candidate machine in the stopped state and is used as the independent operating current of the candidate machine in subsequent calculations. When a machine reduction command is triggered, since the candidate machine is in a running state, the system directly obtains the independent operating current of the candidate machine in the running state and uses it as the independent operating current of the candidate machine in subsequent calculations.

[0041] The calibration method for the preset upper and lower limits of the intensity threshold is as follows: First, an industrial air conditioning operation test environment without structural faults is established. Under the reference steady state with the variable frequency compressor at its rated intermediate frequency and the mains frequency compressor completely stopped, the step heat load input to the controlled area is gradually increased until the real-time temperature of the controlled area begins to fluctuate and deviates from the target temperature of the controlled area. The absolute temperature difference between the real-time temperature of the controlled area and the target temperature at the moment when the thermal equilibrium is disrupted is recorded using a temperature sensor, and this absolute temperature difference is established as the allowable temperature deviation. Then, the technical specifications of the mains frequency compressor are consulted to extract the rated values ​​of the mains frequency compressor. The starting shaft power at a constant exhaust pressure is divided by the unit indicated power of the variable frequency compressor at a single Hertz frequency to calculate the equivalent frequency step value required for grid connection of the industrial frequency compressor. Finally, using the dynamic simulation model of the refrigeration system, the allowable temperature deviation is used as the static balance input, and the equivalent frequency step value is used as the dynamic disturbance term. These are substituted into the derivation equation of the real-time heat load intensity index for boundary limit calculation. The upper limit of the calculation that satisfies the thermodynamic state stability and convergence of the system after adding the compressor is calibrated as the preset intensity threshold upper limit, and the lower limit of the calculation that satisfies the thermodynamic state stability and convergence of the system after reducing the compressor is calibrated as the preset intensity threshold lower limit.

[0042] S3. Calculate the energy efficiency degradation coefficient of the candidate machine.

[0043] It should be noted that in harsh industrial environments with long-term high-load operation, increased exhaust pressure leads to increased refrigerant reflux and decreased volumetric efficiency. At the same time, long-term mechanical wear increases the physical internal leakage between the dynamic and static sealing surfaces inside the compressor. This invention combines real-time acquired thermodynamic operating parameters with long-term operating wear data retrieved from the underlying database to construct a dynamic reduction model based on the physical degradation of thermodynamic indicated power and volumetric efficiency. This model can calculate and obtain the actual output loss rate of the industrial frequency compressor relative to its rated factory condition in real time, thereby correcting the theoretical prediction deviation of treating the operating equipment as a constant ideal refrigeration source and providing a real benchmark for the physical characterization of refrigeration capacity for subsequent cooling capacity compensation calculations.

[0044] Specifically, the performance degradation degree of the industrial frequency compressor is comprehensively determined from the dimensions of thermodynamic volumetric efficiency, mechanical fatigue aging, and electrical input, and the energy efficiency degradation coefficient of the candidate compressor is obtained, including: First, based on the thermodynamic physical premise of gas expansion inside the compressor cylinder, the clearance volume ratio of the candidate compressor and the isentropic index of the refrigerant gas are introduced to calculate the thermodynamic volumetric efficiency under the current pipeline pressure ratio. The calculation formula is as follows: In the formula, For a moment Thermodynamic volumetric efficiency; This is the current running time; For a moment Exhaust pressure of industrial air conditioners; For a moment Suction pressure of industrial air conditioners; The clearance volume ratio of the candidate machine is calibrated as follows: the implementation personnel shall refer to the mechanical structure assembly drawings of the compressor manufactured by the manufacturer, extract the physical values ​​of the total geometric volume of the cylinder and the clearance volume of the end face, and calculate the ratio of the clearance volume to the total geometric volume of the cylinder for engineering calibration. The isentropic index of the refrigerant gas is calibrated by consulting the refrigerant physical property parameter manual and obtaining the ratio of the isobaric specific heat capacity to the isovolumetric specific heat capacity under standard operating conditions for the current type of refrigerant.

[0045] When calculated When it is less than 0, directly set This is to ensure that the subsequently calculated cooling capacity always falls within the non-negative range that conforms to physical laws.

[0046] This calculation reveals the thermodynamic mechanism by which high-pressure gas expands and occupies the suction volume within the compressor's internal clearance volume, when the discharge pressure of the industrial air conditioner... Increase the suction pressure of industrial air conditioners When the overall operating pressure ratio is reduced, the physical volume of the clearance gas expands dramatically, leading to a decrease in thermodynamic volumetric efficiency. The significant reduction accurately reflects the decrease in refrigeration performance caused by the reduction in effective refrigerant suction volume under severe high-pressure conditions.

[0047] Then, the ratio of the cumulative fatigue operating time of the candidate machine to its design life is calculated, and this ratio is subtracted from 1 to obtain the long-term operating factor characterizing the degree of equipment wear. The formula is as follows: In the formula, For a moment Long-term operating factors; This is the current running time; For a moment The cumulative fatigue operating time of the candidate machine; This refers to the design life of the candidate machine.

[0048] When calculated When it is less than 0, directly set This is to ensure that the energy efficiency degradation coefficient calculated subsequently is in the non-negative range that conforms to physical laws.

[0049] This calculation formula reflects the increase in physical internal leakage of the mechanical rotor sealing surface caused by natural aging of industrial air conditioning equipment by calculating the proportion of remaining mechanical life. This is based on the cumulative fatigue operating time of the candidate machine. The closer the numerical value is to the design life of the candidate machine At that time, long-term operating factor The closer the value of collapses to zero, the more severe the degradation of fluid sealing performance caused by mechanical wear becomes.

[0050] Next, the independent operating current of the candidate machine is calculated. With the rated current of the candidate machine The ratio is used to obtain the power input load factor. This allows us to determine the spindle power input loss of the compressor under the current operating conditions. This is the current running time; For a moment The independent operating current of the candidate unit; this calculation formula compares the actual current consumption with the rated nominal current through physical comparison. When it decreases, the power input load factor A direct reduction indicates that the current real shaft power input level delivered to the refrigerant fluid by the candidate engine has physically degraded relative to its rated state.

[0051] Finally, following the thermodynamic law that the system cooling capacity is proportional to the product of volumetric efficiency, indicated efficiency, and shaft power, the formulas for calculating the electrical input load rate and the long-term operating factor are substituted into the initial reduction formula, which is composed of the product of relative volumetric efficiency, long-term operating factor, and electrical input load rate, to obtain the expanded formula. The formula for calculating thermodynamic volumetric efficiency is then substituted into the numerator of the expanded formula. After algebraic merging and rearrangement, the final formula for calculating the energy efficiency degradation coefficient of the candidate unit is obtained, which is: In the formula, For a moment Energy efficiency degradation coefficient of candidate machines; The clearance volume ratio of the candidate machine; For a moment Exhaust pressure of industrial air conditioners; For a moment Suction pressure of industrial air conditioners; The isentropic index of the refrigerant gas; For a moment The cumulative fatigue operating time of the candidate machine; The design life of the candidate machine; For a moment Independent operating current of the candidate machine; This is the rated current of the candidate machine; This is the current running time; The rated volumetric efficiency is calibrated by the compressor manufacturer through a rigorous measurement of the physical ratio between the actual discharge volume and the theoretical physical discharge volume under standard constant temperature test conditions.

[0052] This calculation formula spans three dimensions: electromechanical, mechanical, and thermal. It comprehensively considers the volumetric attenuation caused by increased compressor pressure ratio, the fluid leakage attenuation caused by mechanical wear, and the axial work reduction caused by decreased drive current. When the equipment encounters extreme high pressure ratios, prolonged fatigue wear, and insufficient motor drive current, the energy efficiency attenuation coefficient... The sharp decrease in the multiplier effect level outputs the proportion of the overall real physical capability loss of the compression equipment at the end of its life cycle.

[0053] S4. Based on the rated cooling capacity and energy efficiency attenuation coefficient of the candidate machine, as well as the maximum operating frequency and maximum cooling capacity of the variable frequency compressor, calculate the frequency callback compensation value of the variable frequency compressor, execute the machine addition or reduction command on the candidate machine, and synchronously adjust the operating frequency of the variable frequency compressor according to the frequency callback compensation value of the variable frequency compressor.

[0054] It should be noted that, in order to achieve a smooth physical energy level switch when adding or removing main units in an industrial air conditioning network system, this invention, based on the actual output capacity of the candidate unit calculated by the aforementioned multi-dimensional aging and degradation mechanism, reversely deduces the mechanical operating frequency that the variable frequency compressor urgently needs to adjust synchronously. This compensation operation aims to completely offset the dynamic cooling capacity increment generated by the instantaneous mechanical frequency conversion adjustment of the variable frequency compressor with the actual cooling capacity physically generated by the newly started or just shut down candidate unit. This maintains a smooth transition of cold source output in terms of the overall balance of cooling capacity in the physical system, eliminating the severe damage to the precision temperature stability of the controlled area caused by the macroscopic cooling capacity step impact of the electric start-up and shutdown of the giant main unit.

[0055] Specifically, the actual physical cooling capacity output of the candidate compressor is determined based on its energy efficiency attenuation coefficient, and then the frequency callback compensation value of the inverter compressor is obtained, including: First, the rated cooling capacity of the candidate machine. Energy efficiency degradation coefficient of candidate machine Multiply by the product to obtain the actual effective cooling capacity of the candidate unit. ,Right now This calculation formula performs a physical-level performance degradation correction on the theoretical cooling capacity at the factory by extracting the energy efficiency degradation coefficient of the candidate unit. When the energy efficiency degradation coefficient of the candidate unit... As the aging process decreases, the actual effective cooling capacity of the candidate unit... The corresponding decrease reflects the actual reduction in mechanical output caused by the combined pressure of industrial equipment fatigue and harsh working conditions.

[0056] Secondly, to maintain a smooth physical transition of the total cooling capacity of the air conditioning system, based on the principles of energy conservation and static balance of cooling capacity, the variable frequency compressor needs to adjust the cooling capacity increment at the moment of main unit switching. The actual effective cooling capacity of the candidate machine must be numerically equivalent. ,Right now This equation establishes a substitution relationship where the sum of the dynamic electrical compensation cooling capacity of the variable frequency compressor and the actual mechanical cooling capacity of the candidate unit is 0, ensuring that the total cooling capacity of the unit will not undergo a physical jump at the moment of electrical switching.

[0057] Next, under the quasi-steady-state physical premise of constant temperature control in an industrial workshop, a proportional mapping mechanism between the cooling capacity output of the variable frequency compressor and the spindle rotation frequency is applied to establish a proportional relationship between the frequency correction compensation value of the variable frequency compressor and the increase in the cooling capacity of the variable frequency compressor. This relationship satisfies the following: In the formula, This is the frequency callback compensation value for the variable frequency compressor; This refers to the maximum operating frequency of the variable frequency compressor. For a moment The increase in cooling capacity of the variable frequency compressor; This is the maximum cooling capacity of the variable frequency compressor; This is the current running time.

[0058] This relationship illustrates the linear positive correlation between the fluid cooling capacity output and the mechanical operating frequency within the rated operating range of the variable frequency motor. When the control system requires the variable frequency compressor to output a greater incremental cooling capacity, this relationship is relevant. At the same time, the frequency callback compensation value of the variable frequency compressor issued to the variable frequency motor needs to be increased proportionally. .

[0059] Finally, based on the equivalent substitution relationship of cooling capacity balance, all the incremental parameters of the variable frequency compressor's cooling capacity in the above proportional relationship are replaced with the actual effective cooling capacity of the candidate machine to obtain the derived proportional relationship. Then, the calculation formula of the actual effective cooling capacity of the candidate machine is substituted into the numerator region of this derived proportional relationship, and both sides of the equation are multiplied by the maximum operating frequency of the variable frequency compressor. After rearranging terms and simplifying algebraically, the final formula for calculating the frequency correction compensation value of the variable frequency compressor is obtained, which is: In the formula, This is the frequency callback compensation value for the variable frequency compressor; This refers to the maximum operating frequency of the variable frequency compressor. The rated cooling capacity of the candidate unit; For a moment Energy efficiency degradation coefficient of candidate machines; This is the maximum cooling capacity of the variable frequency compressor; This is the current running time.

[0060] This calculation establishes the relationship between the candidate engine's degradation state and the frequency converter's adjustment amplitude: when the candidate engine's energy efficiency attenuation coefficient... When the frequency is reduced due to severe mechanical aging or high pressure resistance, the system sends a frequency callback compensation value to the variable frequency compressor. The synchronous proportional physical reduction ensures that the electrical frequency compensation range of the variable frequency compressor matches the actual physical capabilities of the old parallel units, avoiding excessive cooling in the machine room and violent temperature fluctuations in the workshop caused by theoretical overcompensation.

[0061] Furthermore, when the underlying logic triggers a machine addition command, the controller engages the AC contactor to start the candidate machine and sets the target frequency of the variable frequency compressor to the algebraic difference between the current operating frequency of the variable frequency compressor and the frequency callback compensation value of the variable frequency compressor; when the underlying logic triggers a machine reduction command, the controller disconnects the AC contactor to stop the candidate machine and sets the target frequency of the variable frequency compressor to the algebraic sum of the current operating frequency of the variable frequency compressor and the frequency callback compensation value of the variable frequency compressor.

[0062] Meanwhile, the control system introduces physical limiting protection logic for the minimum and maximum operating frequencies of the variable frequency compressor: if the calculated target frequency of the variable frequency compressor is lower than the minimum operating frequency of the variable frequency compressor, the underlying controller locks the target frequency of the variable frequency compressor to the minimum operating frequency of the variable frequency compressor; if the calculated target frequency of the variable frequency compressor is higher than the maximum operating frequency of the variable frequency compressor, the underlying controller locks the target frequency of the variable frequency compressor to the maximum operating frequency of the variable frequency compressor. This prevents the variable frequency compressor from falling into the low-frequency unstable operating zone or triggering hardware overload shutdown protection during dynamic electrical callback, ensuring that the underlying electrical control commands are always executed safely within the mechanical and fluid physical safety boundaries of the equipment.

[0063] This invention also discloses an industrial air conditioning multi-parameter adaptive control system, including a processor and a memory. The memory stores computer program instructions, which, when executed by the processor, implement an industrial air conditioning multi-parameter adaptive control method according to the present invention.

[0064] The system also includes other components well known to those skilled in the art, such as communication buses and communication interfaces, the settings and functions of which are known in the art and will not be described in detail here.

[0065] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A multi-parameter adaptive control method for an industrial air conditioner, wherein the industrial air conditioner adopts a parallel unit architecture of one variable frequency compressor and multiple fixed frequency compressors, characterized in that, include: The system acquires real-time operating parameters of industrial air conditioners, calculates real-time heat load intensity index based on these parameters, and determines whether to add or remove units based on the relationship between the real-time heat load intensity index and the preset upper and lower limits of the intensity threshold, and selects candidate units from multiple industrial frequency compressors. The energy efficiency attenuation coefficient of the candidate air conditioner is calculated based on the suction pressure, exhaust pressure and independent operating current of the candidate air conditioner in the real-time operating parameters. Based on the candidate machine's rated cooling capacity, energy efficiency attenuation coefficient, maximum operating frequency and maximum cooling capacity of the variable frequency compressor, calculate the frequency callback compensation value of the variable frequency compressor, execute the add or remove machine command on the candidate machine, and synchronously adjust the current operating frequency of the variable frequency compressor according to the frequency callback compensation value.

2. The multi-parameter adaptive control method for industrial air conditioning according to claim 1, characterized in that, The real-time operating parameters also include the real-time temperature and target temperature of the controlled area, the evaporation temperature of the industrial air conditioner, and the independent operating current of each industrial frequency compressor.

3. The multi-parameter adaptive control method for industrial air conditioning according to claim 2, characterized in that, After acquiring the real-time operating parameters of the industrial air conditioner, the adaptive control method further includes: A circular data buffer is created inside the programmable logic controller; the time series data composed of the collected real-time operating parameters is subjected to moving average filtering to remove high-frequency electrical noise interference and obtain smoothed real-time operating parameters.

4. The multi-parameter adaptive control method for industrial air conditioning according to claim 2, characterized in that, The calculation of the real-time heat load intensity index based on real-time operating parameters includes: The static temperature deviation is obtained by calculating the algebraic difference between the real-time temperature of the controlled area and the target temperature of the controlled area. The first-order backward difference method is used to calculate the data sequence of evaporation temperature in industrial air conditioning and obtain the time derivative of evaporation temperature; the time derivative of evaporation temperature is converted into equivalent dynamic temperature deviation using the system thermal time constant. Construct a nonlinear gain factor based on the absolute value of static temperature deviation and the temperature control sensitivity constant; The real-time heat load intensity index is obtained by superimposing the static temperature deviation, the equivalent dynamic temperature deviation, and the nonlinear gain factor.

5. The multi-parameter adaptive control method for industrial air conditioning according to claim 2, characterized in that, The step of determining the addition or reduction command and locking candidate compressors from multiple industrial frequency compressors based on the relationship between the real-time heat load intensity index and the preset upper and lower limits of the intensity threshold includes: When the real-time heat load intensity index is detected to be greater than the preset intensity threshold, a machine addition command is triggered, and the industrial frequency compressor with the shortest cumulative fatigue running time is selected and locked as a candidate machine. When the real-time heat load intensity index is detected to be less than the preset intensity threshold lower limit, a reduction command is triggered, and the industrial frequency compressor with the longest cumulative fatigue running time is selected as the candidate compressor. When the addition command is triggered, the independent operating current of all running industrial frequency compressors is collected and the average value is calculated as the independent operating current of the candidate compressors in the shutdown state. When a reduction command is triggered, the independent operating current of the candidate machine in the running state is directly obtained.

6. The multi-parameter adaptive control method for industrial air conditioning according to claim 5, characterized in that, Obtaining the cumulative fatigue running time includes: Capture the electrical feedback signals of the AC contactor of the industrial frequency compressor to obtain the stop and start times of each start-stop cycle experienced by the industrial frequency compressor; The total physical operating time is obtained by subtracting the stopping time from the starting time of all start-stop cycles experienced by the industrial frequency compressor and summing the results. The equivalent time of transient impact wear is obtained by multiplying the start-stop damage conversion time by the total number of start-stop cycles; The cumulative fatigue operating time of the power frequency compressor is obtained by superimposing the total physical operating time with the equivalent time of transient impact wear.

7. The multi-parameter adaptive control method for industrial air conditioning according to claim 1, characterized in that, The calculation of the energy efficiency attenuation coefficient of the candidate air conditioner based on the suction pressure, exhaust pressure, and independent operating current of the candidate air conditioner includes: The thermodynamic volumetric efficiency under the pipeline pressure ratio is calculated based on the clearance volume ratio of the candidate engine and the isentropic index of the refrigerant gas. The ratio of the cumulative fatigue operating time of the candidate machine to the design life of the candidate machine is calculated to obtain the long-term operating factor. The ratio of the independent operating current of the candidate unit to the rated current of the candidate unit is calculated to obtain the power input load factor. Divide the thermodynamic volumetric efficiency by the rated volumetric efficiency, and multiply it by the long-term operating factor and the electrical input load rate to obtain the energy efficiency degradation coefficient of the candidate machine.

8. The multi-parameter adaptive control method for industrial air conditioning according to claim 1, characterized in that, The calculation of the frequency callback compensation value of the variable frequency compressor based on the rated cooling capacity, energy efficiency attenuation coefficient, maximum operating frequency and maximum cooling capacity of the candidate compressor includes: Multiply the rated cooling capacity of the candidate unit by the energy efficiency attenuation coefficient to obtain the actual effective cooling capacity of the candidate unit; Based on the principle of static balance of cooling capacity, an equivalent substitution relationship between the incremental cooling capacity of the variable frequency compressor and the actual effective cooling capacity of the candidate compressor is established; Establish a positive proportional mapping relationship between the frequency callback compensation value of the variable frequency compressor, the maximum operating frequency of the variable frequency compressor, the incremental cooling capacity of the variable frequency compressor, and the maximum cooling capacity of the variable frequency compressor; The frequency callback compensation value of the variable frequency compressor can be obtained by solving the equivalent substitution relationship and the proportional mapping relationship simultaneously.

9. The multi-parameter adaptive control method for industrial air conditioning according to claim 1, characterized in that, The step of executing add or remove machine commands for candidate compressors and synchronously adjusting the current operating frequency of the variable frequency compressor according to the frequency callback compensation value includes: When the machine addition command is triggered, the AC contactor is engaged to start the candidate machine, and the target frequency of the variable frequency compressor is set to the algebraic difference between the current operating frequency of the variable frequency compressor and the frequency callback compensation value. When the reduction command is triggered, the AC contactor is disconnected to stop the candidate machine, and the target frequency of the variable frequency compressor is set to the algebraic sum of the current operating frequency of the variable frequency compressor and the frequency callback compensation value. When the calculated target frequency of the variable frequency compressor is lower than the minimum operating frequency of the variable frequency compressor, the target frequency of the variable frequency compressor is locked to the minimum operating frequency; when the calculated target frequency of the variable frequency compressor is higher than the maximum operating frequency of the variable frequency compressor, the target frequency of the variable frequency compressor is locked to the maximum frequency.

10. A multi-parameter adaptive control system for industrial air conditioning, characterized in that, include: A processor and a memory, wherein the memory stores computer program instructions that, when executed by the processor, implement a multi-parameter adaptive control method for industrial air conditioning according to any one of claims 1-9.

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