Intelligent variable frequency air conditioner device based on multi-sensor fusion and control system thereof

Abstract

The application relates to the field of air conditioning equipment, and discloses an intelligent variable-frequency air conditioner device based on multi-sensor fusion and a control system thereof. The device comprises a main control unit, and an indoor return air temperature sensor, an infrared wall temperature sensor, an outdoor environment temperature sensor, a solar radiation sensor, a variable-frequency compressor, a guide vane stepping motor, an electronic expansion valve and a four-way valve connected with the main control unit. The control system estimates the equivalent heat capacity of a building and the comprehensive heat transfer conductivity online through a parameter identification module, calculates a dynamic heat loss power as a feedforward quantity to regulate the frequency of the compressor; the air flow control module controls the deflection of the guide vane to send air and corrects the action temperature weight when the wall cold radiation exceeds the limit; and the defrosting joint control module adjusts the defrosting timing and the throttling opening according to the heat storage state of the building. The application can compensate for the environmental heat load fluctuation in advance, actively eliminate the wall cold radiation, reduce the room temperature drop caused by defrosting, and improve the heating stability.

Description

Technical Field

[0001] This invention relates to the field of air conditioning equipment technology, specifically to an intelligent variable frequency air conditioning device and its control system based on multi-sensor fusion. Background Technology

[0002] Variable frequency air conditioning systems are widely used in building temperature control because they can dynamically adjust the compressor speed according to heat load demand. Current variable frequency air conditioning control logic mainly relies on temperature sensors installed at the return air vent of the indoor unit to collect indoor air temperature data and compare this measured temperature with the user-set target temperature. The main control unit then uses feedback adjustment algorithms to calculate and output control commands based on the acquired temperature deviation data, thereby changing the compressor's operating frequency and the throttling opening of the electronic expansion valve to maintain the indoor air temperature within the set dynamic equilibrium range.

[0003] However, this control mode based solely on indoor air temperature feedback exhibits significant response lag in actual operation. When the outdoor ambient temperature drops sharply or the outdoor solar radiation intensity decreases significantly, the heat loss from the building envelope increases rapidly. Since the equivalent heat capacity of air is much smaller than that of solid walls, the change in indoor air temperature is not significant in the initial stages of heat leakage. The system cannot detect changes in heat load in advance and proactively increase the compressor's heating output, leading to a substantial drop in room temperature subsequently. Simultaneously, in low-temperature, high-heat-leakage environments, the surface temperature of indoor walls is typically much lower than the air temperature, forming a cold radiation boundary. Existing air conditioning systems, lacking means to monitor wall surface temperature, maintain a conventional uniform airflow pattern and fixed control reference weights. This not only fails to proactively intervene and increase wall temperature to improve perceived temperature but also causes the feedback control loop to deviate from the actual physical heat exchange state.

[0004] Furthermore, during winter heating operation, frost buildup on the outdoor heat exchanger triggers the defrost process. Conventional defrost control logic typically involves directly switching the four-way valve to reverse the refrigerant circulation, forcing the indoor unit to absorb heat from the room to melt the frost on the outdoor unit's surface. In this physical conversion process, existing systems do not pre-assess the current sensible heat storage status within the building structure, nor do they calculate the expected total heat loss from the building to the outside during defrost operation. If the building's temperature is low and the ambient heat loss rate is high, the rapid heat absorption by the refrigerant during defrost and the continuous heat dissipation from the external environment will create a combined physical effect, causing a sharp drop in indoor air temperature within a short period, severely disrupting the continuity and stability of the heating process. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides an intelligent variable frequency air conditioning device and its control system based on multi-sensor fusion. This solves the problem that existing air conditioning systems lack comprehensive perception of the thermal properties of the building envelope and the heat loss from the outdoor environment, resulting in excessive fluctuations in indoor temperature when external heat leakage increases dramatically or when the equipment absorbs heat during defrosting. Furthermore, they cannot actively identify and eliminate the deviation in perceived temperature caused by cold radiation from the walls.

[0006] To achieve the above objectives, the present invention provides the following technical solution: The first aspect of this invention provides an intelligent variable frequency air conditioning device based on multi-sensor fusion, comprising: Indoor return air temperature sensor is used to detect the indoor air temperature at the return air vent of the indoor unit of the air conditioner; Infrared wall temperature sensor is used to detect the infrared radiation temperature of indoor wall surfaces; Outdoor ambient temperature sensor, used to detect outdoor ambient temperature; A solar radiation sensor is used to detect the total outdoor solar irradiance. The main control unit is used to receive environmental status parameters and output drive control signals; A variable frequency compressor, used to perform variable frequency operation according to the drive control signal; A stepper motor for the air guide vanes is used to adjust the deflection angle of the air guide vanes according to the drive control signal. An electronic expansion valve is used to adjust the refrigerant throttling opening according to the drive control signal; A four-way valve is used to switch the refrigerant circulation direction according to the drive control signal; The indoor return air temperature sensor, infrared wall temperature sensor, outdoor ambient temperature sensor, and solar radiation sensor are all connected to the main control unit via a signal bus. The variable frequency compressor, the guide vane stepper motor, the electronic expansion valve, and the four-way valve are respectively connected to the main control unit through an electrical drive interface.

[0007] Through the technical solution of the first aspect mentioned above, the present invention utilizes a heterogeneous sensor array to construct a comprehensive physical environment monitoring network, which uniformly reads indoor air, wall radiation, outdoor ambient temperature and total solar radiation illuminance to the main control unit, providing underlying data support for subsequent thermal parameter identification and equipment collaborative control, and realizing the coupling of external environmental characteristics and air conditioning underlying hardware.

[0008] A second aspect of the present invention provides a control system for an intelligent variable frequency air conditioning device based on multi-sensor fusion, applied to the intelligent variable frequency air conditioning device based on multi-sensor fusion provided in the first aspect, comprising: The data acquisition module is used to read the environmental state parameters output by each sensor, perform filtering operations, and output the filtered environmental state parameters. The parameter identification module is used to receive the filtered environmental state parameters output by the data acquisition module, extract the actual output heating power, identify the equivalent comprehensive thermal conductivity and equivalent heat capacity of the building envelope, and calculate and output the real-time dynamic heat loss power. The airflow control module is used to receive the equivalent comprehensive thermal conductivity output by the parameter identification module, calculate the gas-solid two-phase temperature difference gradient in the indoor space, output the air delivery vector command to the stepper motor of the air guide blade when the preset cold radiation critical threshold is exceeded, and calculate and output the dynamic weighting coefficient of the air action temperature. The variable frequency control module is used to receive the real-time dynamic heat loss power output by the parameter identification module and the dynamic weighting coefficient of the air action temperature output by the airflow control module, calculate the feedforward reference frequency and the feedback fine-tuning frequency, combine the two and limit them, and output the target operating frequency command to the variable frequency compressor. The defrosting control module is used to receive the equivalent heat capacity and real-time dynamic heat loss power output by the parameter identification module when the defrosting trigger condition is met, compare the heat balance state and output the switching related command to the four-way valve, and output the opening adjustment command to the electronic expansion valve during the switching period.

[0009] Through the technical solution of the second aspect mentioned above, this invention introduces the heat capacity and thermal conductivity of the building envelope as dynamic control variables into the underlying operating logic of the air conditioning system. By actively intervening in the heat exchange boundary of the wall through the airflow control module, and utilizing the feedforward and feedback mechanism of the frequency converter control module to adapt to changes in the external physical environment, and adjusting the refrigerant circulation in conjunction with the sensible heat state of the building during the defrosting stage, the heating stability of the air conditioning system under complex operating conditions and high heat loss environments is improved.

[0010] Furthermore, the parameter identification module extracts the actual output heating power, identifies the equivalent comprehensive thermal conductivity of the building envelope, calculates and outputs the real-time dynamic heat loss power, specifically used for: Extract the actual output heating power, divide the actual output heating power by the difference between the filtered indoor air temperature and the outdoor ambient temperature, and obtain the equivalent comprehensive thermal conductivity. The real-time dynamic heat loss power is calculated by multiplying the equivalent comprehensive thermal conductivity by the difference, and subtracting the product of the preset estimated value of the comprehensive solar heat gain coefficient of the building window system and the filtered total outdoor solar irradiance.

[0011] Through the above technical solution, the system calculates the building's equivalent comprehensive thermal conductivity within the heating steady-state range using the actual output heating power and the indoor-outdoor temperature difference, and eliminates the solar thermal radiation compensation term from the windows in the equation for calculating dynamic heat loss power. This calculation eliminates the pseudo-heat load interference caused by external sunlight, outputs an objective and actual heat loss power value, and improves the calculation accuracy of the subsequent compressor frequency conversion feedforward compensation algorithm.

[0012] Furthermore, the parameter identification module extracts the actual output heating power to identify the equivalent heat capacity of the building envelope, specifically for: During the unsteady heating phase at the initial stage of system startup, the integral value of the actual output heating power over time is recorded within the set calculation period. Obtain the difference between the filtered infrared radiation temperature of the indoor wall surface at the end of the calculation within the corresponding calculation time period and the filtered infrared radiation temperature of the indoor wall surface at the start of the calculation. The equivalent heat capacity of the building envelope is calculated by dividing the integral value by the difference.

[0013] Through the above technical solution, the system obtains the time integral of the output energy during the initial unsteady heating phase and divides it by the simultaneous increase in indoor wall temperature to identify the building's equivalent heat capacity through online calculation. This logic transforms the physical properties of the building environment's heat storage into specific system control parameters, providing numerical basis for subsequent sensible heat assessment and heat storage intervention during defrosting cycles.

[0014] Furthermore, the airflow control module calculates the gas-solid two-phase temperature gradient in the indoor space, and outputs an airflow vector command to the stepper motor of the air guide vanes when the gradient exceeds a preset cold radiation critical threshold. Specifically, this is used for: The temperature gradient is obtained by calculating the difference between the filtered indoor air temperature and the infrared radiation temperature of the indoor wall surface. When the equivalent comprehensive thermal conductivity is determined to be greater than the preset heat loss rate threshold and the temperature difference gradient is greater than the preset cold radiation critical threshold, a pulse sequence signal is generated and output to the stepper motor of the air guide blade, driving the air guide blade of the indoor unit of the air conditioner to rotate to the limit deflection angle, forming an attached jet.

[0015] Through the above technical solution, when the logic detects that the house is in a state of high heat loss and that there is a temperature gradient on the interior walls that causes cold radiation, the control system forcibly changes the airflow organization of the indoor air conditioning unit. The attached jet formed by the movement of the air guide vanes guides the high-temperature air directly across the interior walls, artificially increasing the convective heat transfer coefficient in the local area. This allows the system to prioritize increasing the surface temperature of the interior walls with the output heat, suppressing the cold radiation phenomenon caused by low wall temperatures to the occupants.

[0016] Furthermore, the airflow control module calculates and outputs a dynamic weighting coefficient for the air's operating temperature, specifically used for: Obtain the baseline weighting coefficients under normal air supply conditions; Calculate the difference between the temperature gradient between the indoor air and the interior wall surface obtained from the current calculation and the critical threshold of cold radiation, and obtain the ratio of the difference to the critical threshold of cold radiation. The updated dynamic weighting coefficient for air action temperature is calculated by subtracting the product of the preset dynamic correction factor and the ratio from the baseline weighting coefficient.

[0017] Through the above technical solution, the proportional boundary between indoor air heat exchange and wall radiative heat exchange changes during the system's attachment jet action. The control system reduces the reference weight coefficient based on the magnitude of the temperature difference gradient exceeding the limit, and increases the multiplicative weight ratio of the wall surface temperature in the dynamic operating temperature model, so that the control target reference surface conforms to the actual heat exchange process under physical intervention.

[0018] Furthermore, the frequency conversion control module calculates the feedforward reference frequency and the feedback fine-tuning frequency, specifically for: Using the real-time dynamic heat loss power as the input index parameter, the preset discrete data mapping table corresponding to the operating frequency and heating power is called to perform a lookup operation to obtain the feedforward reference frequency. The dynamic effect temperature is calculated by weighting and summing the filtered indoor air temperature and the infrared radiation temperature of the indoor wall surface using the aforementioned dynamic weighting coefficient for air effect temperature. The deviation between the user-set target temperature and the dynamic operating temperature is used as an input variable. The proportional-integral-derivative control algorithm is executed to output the feedback fine-tuning frequency.

[0019] Through the above technical solution, the system uses real-time dynamic heat loss power as a feedforward quantity to obtain the fundamental frequency by looking up a table, and introduces the operating temperature deviation value as an input quantity for PID proportional-integral-derivative calculation. The feedforward path is responsible for offsetting load fluctuations caused by external heat leakage fluctuations, and the feedback path is responsible for eliminating indoor temperature setpoint deviations. Combined with the control architecture, the system's response rate to sudden environmental changes is improved, and the heating steady-state convergence time is shortened.

[0020] Furthermore, the variable frequency control module combines and limits the two factors, then outputs a target operating frequency command to the variable frequency compressor, specifically for: The initial synthesized frequency is obtained by adding the feedforward reference frequency and the feedback fine-tuning frequency. When it is determined that the current house is in a state of high heat loss, the clamping upper limit frequency is calculated by multiplying the maximum allowable operating frequency of the variable frequency compressor by a derating factor of less than 1. The initial synthesized frequency is compared with the clamping upper limit frequency, and the smaller value between the two is selected as the final target operating frequency command.

[0021] Through the above technical solution, under high heat loss identification conditions, the system suppresses the compressor's extreme high-frequency output capability by using a derating factor. Since rooms with high heat leakage cannot retain the sensible heat of the air for a long time, limiting the peak operating frequency can prevent subsequent accelerated temperature loss caused by short-term overheating of the indoor air, and block the frequent power oscillation of the variable frequency compressor between frequency increase and decrease, thus maintaining stable equipment operation.

[0022] Furthermore, the defrosting control module compares the thermal balance state and outputs switching-related commands to the four-way valve, specifically for: The current sensible heat storage capacity is estimated by calling the equivalent heat capacity and the infrared radiation temperature of the indoor wall surface, and the real-time dynamic heat loss power is multiplied by the system's preset estimated defrosting time to calculate the total heat loss. When it is determined that the sensible heat storage capacity is less than the sum of the total heat leakage and the preset safe heat margin, a delayed reversing command is output to the four-way valve. At the same time, the variable frequency compressor is forced to operate at the clamping upper limit frequency and the guide vane stepper motor is linked to establish an attached jet state for heat storage.

[0023] Through the above technical solution, before the outdoor unit meets the defrost trigger conditions, the system calculates and compares the sensible heat storage capacity of the wall with the expected total heat loss during defrost. When the sensible heat storage capacity does not meet the preset margin condition, the control loop intercepts the refrigerant reversal command and performs short-term forced heat storage on the wall through high-frequency operation combined with attached airflow. This joint control strategy provides a physical heat source buffer for the defrost heat absorption cycle, preventing a significant drop in indoor ambient temperature caused by defrosting.

[0024] Furthermore, the defrosting control module outputs an opening adjustment command to the electronic expansion valve during the reversing process, specifically for: During the defrosting cycle, a discrete differential operation is performed on the infrared radiation temperature of the indoor wall surface within the continuous sampling period to obtain the rate of decrease of the current indoor wall surface temperature. The updated opening step command of the electronic expansion valve is calculated by adding the preset positive throttling gain coefficient and the product of the decrease rate of change to the set baseline defrosting opening step number.

[0025] Through the above technical solution, during the defrosting cycle after the four-way valve reverses, the indoor unit of the air conditioner transforms into an evaporator and absorbs indoor heat. The control loop obtains the rate of heat loss by monitoring the rate of decrease in the infrared radiation temperature of the wall, and accordingly adjusts the refrigerant throttling opening step in a closed loop. When the ambient heat loss rate is too high, the system correspondingly reduces the opening of the electronic expansion valve to limit the heat absorption capacity of the refrigerant on the indoor side, thereby slowing down the cooling rate of the indoor environment.

[0026] This invention provides an intelligent variable frequency air conditioning device and its control system based on multi-sensor fusion. It has the following beneficial effects: 1. This invention utilizes sensors for indoor temperature, wall radiant temperature, outdoor temperature, and solar radiation to acquire environmental parameters, identify the building's overall thermal conductivity, and calculate the real-time dynamic heat loss power after eliminating the influence of solar radiation. The system uses this heat loss power as a feedforward adjustment variable, combined with a feedback mechanism for indoor temperature deviation, to jointly control the frequency of the variable frequency compressor. This control method can compensate in advance for heat load fluctuations caused by drops in outdoor temperature and changes in sunlight, avoiding the lag caused by single temperature feedback and reducing the amplitude of indoor temperature fluctuations.

[0027] 2. This invention calculates the temperature gradient between room temperature and wall temperature in real time through an airflow control module. When high heat loss in the environment is detected and the temperature difference exceeds the limit, the air guide vanes are deflected to form an attached jet that directly delivers air to the wall. Simultaneously, the weighting coefficients of air and wall temperatures in the control model are corrected. This action proactively alters the indoor airflow organization, prioritizing the increase of the interior wall surface temperature to eliminate cold radiation. Simultaneously, it makes the system's frequency conversion feedback reference value more consistent with the actual physical heat exchange state, improving the perceived heating temperature in low-temperature, high-heat-leakage environments.

[0028] 3. This invention introduces the building's equivalent heat capacity and wall temperature as judgment criteria during the defrosting process. When defrosting conditions are triggered, the sensible heat storage capacity of the wall and the total heat loss during defrosting are assessed in advance. If the heat storage capacity is determined to be insufficient, the system temporarily suspends the four-way valve switching and forces the equipment to perform short-term heat storage on the wall. Furthermore, during the formal defrosting period, the opening of the electronic expansion valve is reduced synchronously according to the slope of the wall temperature drop. This mechanism provides a basic heat reserve for the defrosting cycle and limits the rate at which the refrigerant absorbs heat from the room, preventing a significant drop in indoor temperature caused by air conditioning defrosting. Attached Figure Description

[0029] Figure 1 This is a perspective view of the device of the present invention; Figure 2 This is a diagram of the control system module architecture of the present invention.

[0030] Among them, 10 is an indoor return air temperature sensor; 20 is an infrared wall temperature sensor; 30 is an outdoor ambient temperature sensor; 40 is a solar radiation sensor; 50 is a main control unit; 60 is a variable frequency compressor; 70 is a stepper motor for air guide vanes; 80 is an electronic expansion valve; and 90 is a four-way valve. Detailed Implementation

[0031] The technical solutions in 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 embodiments of the present invention, and not all embodiments. 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.

[0032] Please see the appendix Figure 1 - Appendix Figure 2 The present invention provides an intelligent variable frequency air conditioning device based on multi-sensor fusion, including: an indoor return air temperature sensor 10, an infrared wall temperature sensor 20, an outdoor ambient temperature sensor 30, a solar radiation sensor 40, a main control unit 50, a variable frequency compressor 60, a guide vane stepper motor 70, an electronic expansion valve 80, and a four-way valve 90.

[0033] Indoor return air temperature sensor 10 is located at the return air vent of the indoor unit of the air conditioner. Infrared wall temperature sensor 20 is installed on the indoor unit panel, with its detection field of view facing the indoor wall. Outdoor ambient temperature sensor 30 and solar radiation sensor 40 are located on the surface of the outdoor unit casing. All of the above sensors are connected to the main control unit 50 via a signal bus. Variable frequency compressor 60, air guide vane stepper motor 70, electronic expansion valve 80, and four-way valve 90 are respectively connected to the main control unit 50 via electrical drive interfaces. The main control unit 50 integrates a data acquisition module, a parameter identification module, an airflow control module, a variable frequency control module, and a defrost control module.

[0034] The control system of the intelligent variable frequency air conditioning unit based on multi-sensor fusion, according to the internal modules of the main control unit 50, includes the following steps in its specific operation process: S10, the data acquisition module reads the environmental status parameters output by the indoor return air temperature sensor 10, infrared wall temperature sensor 20, outdoor ambient temperature sensor 30 and solar radiation sensor 40 according to the set sampling period, performs filtering calculations and transmits them to the parameter identification module. S20, the parameter identification module extracts the actual heating power when the system enters the heating steady state range, and identifies the equivalent comprehensive thermal conductivity and equivalent heat capacity of the building envelope by combining environmental state parameters, and calculates the real-time dynamic heat loss power. S30, the airflow control module receives the equivalent comprehensive heat transfer conductivity and calculates the indoor temperature difference gradient. When it is determined that the building is in a high heat loss state and the temperature difference gradient exceeds the set threshold, the guide vane stepper motor 70 sends a wind vector command to correct the convective heat transfer coefficient of the inner wall surface, and synchronously updates and outputs the dynamic weight coefficient of the operating temperature. S40, the frequency conversion control module calculates the feedforward reference frequency based on dynamic heat loss power, calculates the feedback fine-tuning frequency based on set temperature, environmental state parameters and dynamic weighting coefficient, combines the feedforward reference frequency and feedback fine-tuning frequency and executes upper limit clamping limit, and outputs the target operating frequency command to the frequency conversion compressor 60. S50, when the defrosting triggering conditions are met, the defrosting control module compares the sensible heat storage of the wall with the total heat leakage during the defrosting period, and sends a delayed switching command or executes a switching command to the four-way valve 90. During the switching operation of the four-way valve 90, the opening command output to the electronic expansion valve 80 is adjusted according to the temperature drop rate of the infrared wall temperature sensor 20.

[0035] To further clarify the control logic and execution details of the system, the following will provide a detailed technical description of the core control components and mathematical model of this invention.

[0036] The data acquisition module is used to obtain multi-dimensional state parameters of the air conditioning operating environment and perform smoothing and anti-interference processing on discrete sampled signals. The specific execution logic of this module includes the following steps: S110 enables synchronous sampling and bus reading of multiple environmental status parameters. The main control unit has a built-in timer, and the data acquisition module triggers data conversion and signal uploading from each sensor based on a set basic sampling period.

[0037] In practical engineering applications, the signal types output by different sensors differ at the physical level. The indoor return air temperature sensor 10 and the outdoor ambient temperature sensor 30 typically use NTC thermistors, and the data acquisition module periodically reads the analog voltage values ​​of their voltage divider ports through the analog-to-digital converter integrated inside the main control unit.

[0038] For the conversion of the resistance value and temperature mapping relationship of the indoor return air temperature sensor 10, those skilled in the art can use the conventional NTC thermistor resistance lookup table technology. The hardware conversion circuit design is a well-known technology in this field and will not be described in detail here.

[0039] The infrared wall temperature sensor 20 typically employs a thermopile-type non-contact infrared temperature measurement array, while the solar radiation sensor 40 typically uses a photoelectric heliometer. Both sensors directly output digital signals. The data acquisition module reads the indoor wall surface infrared radiation temperature data output by the infrared wall temperature sensor 20 and the outdoor total solar irradiance data output by the solar radiation sensor 40 via a digital communication bus.

[0040] The aforementioned differential reading mechanism of the underlying hardware interface ensures that multi-source heterogeneous parameters can be uniformly converted into a standard data matrix for use by the core algorithm.

[0041] S120 performs a first-order low-pass filtering operation on discrete signals. Occasional movement of people within the infrared thermography field of view can cause sudden changes in local infrared radiation, and cloud cover can lead to high-frequency fluctuations in solar irradiance. Directly inputting the raw sampled data into subsequent parameter identification and frequency conversion control logic can easily cause disordered oscillations in the operating frequency of the variable frequency compressor 60. The data acquisition module performs a first-order low-pass filtering algorithm separately on each raw environmental state parameter acquired in S110. Taking the filtering operation of indoor air temperature as an example, its digital difference equation expression is as follows: ; In the formula, The filtered indoor air temperature at the current sampling time; These are the filtering and smoothing coefficients; The original indoor air temperature output by the indoor return air temperature sensor 10 at the current sampling time; The filtered indoor air temperature at the previous sampling time; The set sampling period.

[0042] The data acquisition module configures independent filtering and smoothing coefficients in the control register of the main control unit for the physical response characteristics of the indoor return air temperature sensor 10, infrared wall temperature sensor 20, outdoor ambient temperature sensor 30, and solar radiation sensor 40.

[0043] This independent configuration allows the system to selectively filter out environmental interference noise in specific frequency bands. The environmental state parameters after filtering are stored in the shared memory area of ​​the main control unit. At the end of a control cycle, the data acquisition module triggers a data update interrupt so that downstream modules can retrieve the parameters in a stable state.

[0044] The parameter identification module is used to transform unknown building physical properties into quantifiable control parameters to support subsequent variable frequency feedforward regulation and airflow intervention calculations. The specific operational logic of this module includes the following steps: S210, Heating steady-state range determination and actual output power extraction. The parameter identification module continuously monitors the rate of change of filtered indoor air temperature. When the absolute value of the differential of indoor air temperature over time is lower than the preset minimum criterion for multiple consecutive sampling periods, the system determines that it has ended the initial temperature rise phase and officially entered the heating steady-state range.

[0045] After entering the steady-state range, the parameter identification module reads the current operating frequency of the variable frequency compressor 60 and the opening data of the electronic expansion valve 80, and estimates the real-time actual output heating power of the variable frequency air conditioning unit by combining the current condensing pressure and evaporating pressure parameters of the system.

[0046] For methods that use compressor operating parameters and refrigerant state parameters to look up tables or fit to calculate the actual output heating power of air conditioning units, those skilled in the art can use standard refrigerant enthalpy difference calculation models or equipment calibration performance curves. The underlying conversion model is a well-known technology in this field and will not be elaborated here.

[0047] S220 is an online estimation of the equivalent comprehensive thermal conductivity and equivalent heat capacity of the building envelope. It confirms that when the building enters a steady-state region, the heating input from the equipment inside the room and the heat lost to the outdoor environment reach a physical dynamic equilibrium.

[0048] The parameter identification module extracts the actual output heating power obtained from S210 and, combined with the filtered indoor air temperature and outdoor ambient temperature, calculates the equivalent comprehensive thermal conductivity. The specific calculation formula is as follows: ; In the formula, The equivalent overall thermal conductivity of the building envelope; The actual output heating power of the inverter air conditioning unit within the heating steady-state range; The filtered indoor air temperature; This is the filtered outdoor ambient temperature.

[0049] During the initial unsteady heating phase of the system startup, the parameter identification module synchronously records the integral value of the input heat during this time period and uses the infrared wall temperature sensor 20 to obtain the temperature rise data of the wall surface during the corresponding time period, thereby estimating the equivalent heat capacity. The calculation formula is as follows: ; In the formula, The equivalent heat capacity of the building envelope; This is the starting calculation time for the heating phase; This is the time when the calculation ends during the heating phase; The actual output heating power that changes continuously with time during the integration period; The filtered infrared radiation temperature of the indoor wall surface at the time of termination of calculation; The filtered infrared radiation temperature of the indoor wall surface at the initial calculation time.

[0050] S230, continuous closed-loop calculation of real-time dynamic heat loss power. After completing the initial building thermal parameter identification, the control system enters a long-term continuous operation and control phase. The parameter identification module constructs a dynamic heat loss power model based on the real-time indoor-outdoor temperature gradient and the solar radiation compensation effect. The parameters calculated and output by this model are used to characterize the net heat loss from the room to the external environment. The specific calculation relationship is as follows: ; In the formula, This represents the real-time dynamic heat loss power at the current sampling moment; To obtain the equivalent overall thermal conductivity for calculation; The filtered indoor air temperature at the current sampling time; The filtered outdoor ambient temperature at the current sampling time; The estimated value of the comprehensive solar heat gain coefficient of the building exterior window system pre-existing inside the main control unit 50; This represents the total outdoor solar irradiance output from solar radiation sensor 40 at the current sampling time, after filtering.

[0051] The parameter identification module continuously refreshes and writes the calculated real-time dynamic heat loss power data into the internal register of the main control unit 50 for use by the airflow control module and the frequency converter control module. This calculation process transforms complex external climate disturbance factors into a single-dimensional heat load compensation requirement.

[0052] The airflow control module is primarily used to actively intervene in the heat exchange process of the walls by physically adjusting the indoor airflow pattern when cold radiation is detected in the building envelope. This module includes the following execution steps: S310, the airflow control module calculates the gas-solid two-phase temperature gradient in the indoor space in real time. The airflow control module extracts the equivalent comprehensive thermal conductivity output by the parameter identification module, and simultaneously retrieves the filtered indoor air temperature and the infrared radiation temperature of the indoor wall surface from the data acquisition module.

[0053] The airflow control module performs differential calculations on these two temperature parameters to obtain the current temperature gradient. When the logic determines that the equivalent comprehensive thermal conductivity is greater than the preset heat loss rate threshold and the temperature gradient is greater than the preset cold radiation critical threshold, it determines that the current room is in a physical state of high heat leakage and cold radiation from the interior walls, triggering the attached jet intervention mechanism.

[0054] S320, the airflow control module sends an air vector deflection command to the guide vane stepper motor 70. After triggering the attached jet intervention mechanism, the airflow control module generates a specific pulse sequence signal and outputs it to the guide vane stepper motor 70, driving the guide vanes of the indoor unit of the air conditioner to rotate to the limit deflection angle.

[0055] This deflection angle guides the high-temperature airflow from the air conditioner away from the center of the indoor space, instead allowing it to glide across the interior wall surface as an adhering jet. This physical intervention aims to artificially increase the convective heat transfer coefficient of the interior wall surface area, allowing heat to be preferentially transferred to the wall surface layer, which is in a state of low thermal resistance.

[0056] For the pulse width modulation and angle closed-loop positioning control of the stepper motor 70 of the air guide blade, those skilled in the art can use conventional motor drive control circuits and position feedback algorithms to achieve it. The underlying hardware drive principle is a well-known technology in this field and will not be described in detail here.

[0057] In S330, the airflow control module synchronously calculates and updates the dynamic weighting coefficients of the operating temperature. Under normal uniform airflow conditions, the weight ratios of air convection heat transfer and wall radiation heat transfer in the human body operating temperature model are relatively fixed, and the system typically uses empirical benchmark weighting coefficients.

[0058] When the attached jet intervention mechanism is implemented, the forced convection action changes the original heat transfer physical boundary conditions in the room. The airflow control module introduces a dynamic correction factor based on the degree of temperature gradient exceeding the limit, and calculates and updates the dynamic weight coefficients in real time. The specific calculation relationship is as follows: ; In the formula, The dynamic weighting coefficients for the air temperature at the current sampling time; This is the baseline weighting coefficient under normal air supply conditions; This is a dynamic correction factor pre-stored within the main control unit 50; This is the temperature gradient between the indoor air and the interior wall surface calculated at the current sampling time. This is the preset critical threshold for cold radiation.

[0059] Under this physical intervention state, the calculated dynamic weighting coefficient of the air interaction temperature decreases, and the system assigns a higher weight to the wall surface temperature in the subsequent feedback control loop. When the airflow control module continuously monitors that the temperature gradient has fallen back to or below the critical threshold for cold radiation, it cancels the air supply vector deflection command, and the guide vane stepper motor 70 drives the guide vanes to return to the normal uniform air supply position in the space. The dynamic weighting coefficient of the air interaction temperature is simultaneously restored to the baseline weighting coefficient. The airflow control module continuously writes the calculated and updated dynamic weighting coefficient into the shared register, which is then used as a basic parameter for downstream frequency modulation logic.

[0060] The variable frequency control module receives dynamic heat load and heat exchange parameters generated by upstream calculations, and generates the underlying control parameters to drive the air conditioning equipment by merging the feedforward compensation signal and the feedback fine-tuning signal. The implementation process of this module includes the following specific steps: S410, the frequency converter control module calculates and generates the feedforward reference frequency. The frequency converter control module reads the real-time dynamic heat loss power calculated by the parameter identification module from its internal registers. The main control unit 50's memory contains a pre-programmed discrete data mapping table corresponding to the operating frequency and heating power of the frequency converter compressor 60. The frequency converter control module uses this real-time dynamic heat loss power as an input index parameter, calls the discrete data mapping table for lookup calculation, and calculates the feedforward reference frequency that can offset the current heat loss from the building.

[0061] This computational execution link enables the system to increase the compressor's output power in advance, before the indoor air temperature physically drops, when the outdoor temperature drops sharply or sunlight disappears, causing an increase in heat leakage in the house.

[0062] S420, the frequency converter control module performs closed-loop calculations for feedback fine-tuning of the frequency. The frequency converter control module reads the updated dynamic weighting coefficients of the air action temperature calculated by the airflow control module, and combines them with the filtered indoor air temperature and the infrared radiation temperature of the indoor wall surface to calculate the dynamic action temperature that characterizes the actual thermal perception of the human body.

[0063] The control system calculates the temperature deviation by subtracting the set temperature input by the user through the interactive terminal from the dynamic operating temperature. The frequency converter control module uses this temperature deviation as input, executes a proportional-integral-derivative (PID) control algorithm, and outputs a feedback fine-tuning frequency. The relevant mathematical formulas are as follows: ; Among them, dynamic operating temperature The calculation relationship is as follows: ; In the formula, Calculate the feedback fine-tuning frequency of the output at the current sampling time; This is the proportional gain coefficient for controlling the algorithm; The target temperature set by the user; The dynamic operating temperature is calculated at the current sampling time; To control the integral gain coefficient of the algorithm; The differential gain coefficient is used to control the algorithm. Update the dynamic weighting coefficient of the air action temperature output by the airflow control module; The filtered indoor air temperature at the current sampling time; The filtered infrared radiation temperature of the indoor wall surface at the current sampling time.

[0064] In step S430, the frequency converter control module performs frequency synthesis and dynamic clamping limitation. The module adds the feedforward reference frequency obtained in step S410 to the feedback fine-tuning frequency obtained in step S420 to obtain the initial synthesized frequency. The module then calls the building heat loss status determination flag from the airflow control module.

[0065] When a house is determined to be in a state of high heat loss, if the air conditioner is allowed to run directly at its maximum rated frequency, the indoor air will be heated rapidly in a short period of time, which will trigger a rapid heat loss in the future, causing the system to fall into a frequent oscillation cycle of increasing and decreasing frequency.

[0066] In this state, the frequency converter control module triggers an adaptive clamping protection mechanism, multiplying the maximum allowable operating frequency of the frequency converter compressor 60 by a derating factor less than 1 to calculate the clamping upper limit frequency. The frequency converter control module compares the initial synthesized frequency with this clamping upper limit frequency and selects the smaller value as the final target operating frequency command.

[0067] After obtaining the target operating frequency command, the frequency converter control module converts it into a corresponding pulse width modulation duty cycle signal and outputs it to the inverter drive circuit of the frequency converter compressor 60 through the electrical interface of the main control unit 50.

[0068] For the generation of pulse width modulation signals and the vector drive operation logic inside the variable frequency compressor 60, those skilled in the art can use conventional microcontroller timer peripherals and motor control algorithm libraries to implement them. The underlying electrical drive principle is a well-known technology in this field and will not be elaborated here.

[0069] The defrosting control module is used to delay intervention when the outdoor unit triggers defrosting requirements, taking into account the indoor building's heat capacity, and dynamically control the throttling depth of the refrigerant circulation during the defrosting cycle. The implementation process of this module includes the following specific steps: The S510 defrost control module performs a thermal balance assessment before defrosting. The main control unit continuously monitors the operating parameters of the outdoor unit coils. When the coil temperature and heating operation time meet the equipment's normal defrost triggering conditions, the defrost control module internally intercepts and triggers the switching signal of the underlying four-way valve. The defrost control module calls the equivalent heat capacity calculated by the parameter identification module and the infrared radiation temperature of the indoor wall surface output by the data acquisition module to estimate the current sensible heat storage of the wall.

[0070] Simultaneously, the defrosting control module extracts the real-time dynamic heat loss power at the current moment and multiplies it by the system's preset estimated defrosting time to calculate the total heat loss from the house to the outside during the entire defrosting cycle.

[0071] S520: The defrosting control module issues a delayed defrosting command and a heat storage execution command based on the evaluation results. The defrosting control module determines whether the sensible heat storage capacity meets the sum of the total heat loss and the preset safe heat margin. If the sensible heat storage capacity is insufficient, the defrosting control module issues a delayed reversing command to the four-way valve relay drive terminal, allowing the system to continue the heating cycle. During this delayed period, the defrosting control module sends a frequency increase intervention flag to the frequency converter control module, forcing the frequency converter compressor to operate at full load at the clamping upper limit frequency, and coordinating with the airflow control module to issue a maximum deflection angle command to the guide vane stepper motor to establish an attached jet state.

[0072] This combined action drives the air conditioner to output a high-intensity hot airflow that directly washes over the interior walls, forcing short-term heat storage. The defrost control module continuously executes the evaluation calculation in step S510 until the calculated sensible heat storage capacity reaches the safe threshold condition. At this point, the delayed reversal command is canceled, and a level switching signal is output to the four-way valve drive circuit, officially initiating the defrost cycle.

[0073] The S530 defrost control module dynamically optimizes the opening of the electronic expansion valve during the defrost cycle. After the four-way valve switches direction, the indoor unit of the air conditioner transforms into an evaporator and begins to forcibly absorb heat from the indoor environment. The defrost control module extracts the infrared radiation temperature of the indoor wall surface during a continuous sampling period and performs discrete differential calculations to obtain the current rate of change of wall temperature decrease.

[0074] The defrosting control module uses the wall temperature drop rate as input parameter to control the opening step number of the electronic expansion valve in a closed-loop manner. The relevant calculation formula is as follows: ; In the formula, The command to calculate and output the electronic expansion valve opening step count at the current sampling time; The number of steps for setting the baseline defrosting opening for the system; This is the positive throttling gain coefficient; This represents the rate of decrease in the indoor wall surface temperature at the current sampling time, calculated using continuous temperature difference and sampling period.

[0075] During the defrosting and heating phase, the indoor wall temperature is trending downwards, and the rate of change in the above calculation is negative. When the indoor wall temperature drops too quickly, the defrosting control module calculates the corresponding reduction in opening steps according to the formula and outputs it to the bottom drive of the electronic expansion valve.

[0076] As the throttling opening decreases, the refrigerant evaporation pressure in the indoor heat exchanger increases accordingly, limiting the heat absorption of the refrigerant per unit time, thereby slowing down the rate of temperature collapse in the indoor environment.

[0077] For the timing pulse distribution and driving of the electronic expansion valve coil, those skilled in the art can use conventional stepper motor driver integrated chips and program logic to implement it. Its control hardware and execution principle are well-known technologies in the field and will not be described in detail here.

[0078] When the coil temperature rises to the defrosting end condition, the defrosting control module restores the heating state of the four-way valve and the normal throttling control of the electronic expansion valve, and the system returns to the normal heating closed-loop logic.

[0079] 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. An intelligent variable frequency air conditioning device based on multi-sensor fusion, characterized in that, include: Indoor return air temperature sensor (10) is used to detect the indoor air temperature at the return air vent of the indoor unit of the air conditioner; Infrared wall temperature sensor (20) is used to detect the infrared radiation temperature of the indoor wall surface; An outdoor ambient temperature sensor (30) is used to detect the outdoor ambient temperature; A solar radiation sensor (40) is used to detect the total outdoor solar irradiance. The main control unit (50) is used to receive environmental state parameters and output drive control signals; A variable frequency compressor (60) is used to perform variable frequency operation according to the drive control signal; A stepper motor (70) for guiding blades is used to adjust the deflection angle of the guiding blades according to the drive control signal. Electronic expansion valve (80) is used to adjust the refrigerant throttling opening according to the drive control signal; A four-way valve (90) is used to switch the refrigerant circulation direction according to the drive control signal; The indoor return air temperature sensor (10), infrared wall temperature sensor (20), outdoor ambient temperature sensor (30), and solar radiation sensor (40) are all connected to the main control unit (50) via a signal bus. The variable frequency compressor (60), the guide vane stepper motor (70), the electronic expansion valve (80), and the four-way valve (90) are respectively connected to the main control unit (50) through the electrical drive interface.

2. A control system for an intelligent variable frequency air conditioning unit based on multi-sensor fusion, applied to the intelligent variable frequency air conditioning unit based on multi-sensor fusion as described in claim 1, characterized in that, include: The data acquisition module is used to read the environmental state parameters output by each sensor, perform filtering operations, and output the filtered environmental state parameters. The parameter identification module is used to receive the filtered environmental state parameters output by the data acquisition module, extract the actual output heating power, identify the equivalent comprehensive thermal conductivity and equivalent heat capacity of the building envelope, and calculate and output the real-time dynamic heat loss power. The airflow control module is used to receive the equivalent comprehensive heat transfer conductivity output by the parameter identification module, calculate the gas-solid two-phase temperature difference gradient in the indoor space, output the air delivery vector command to the guide vane stepper motor (70) when the preset cold radiation critical threshold is exceeded, and calculate the output air action temperature dynamic weighting coefficient. The variable frequency control module is used to receive the real-time dynamic heat loss power output by the parameter identification module and the dynamic weighting coefficient of the air action temperature output by the airflow control module, calculate the feedforward reference frequency and the feedback fine-tuning frequency, combine the two and limit them, and output the target operating frequency command to the variable frequency compressor (60). The defrosting control module is used to receive the equivalent heat capacity and real-time dynamic heat loss power output by the parameter identification module when the defrosting trigger condition is met, compare the heat balance state and output the switching related command to the four-way valve (90), and output the opening adjustment command to the electronic expansion valve (80) during the switching period.

3. The control system of the intelligent variable frequency air conditioning device based on multi-sensor fusion according to claim 2, characterized in that, The parameter identification module extracts the actual output heating power, identifies the equivalent comprehensive thermal conductivity of the building envelope, calculates and outputs the real-time dynamic heat loss power, and is specifically used for: Extract the actual output heating power, divide the actual output heating power by the difference between the filtered indoor air temperature and the outdoor ambient temperature, and obtain the equivalent comprehensive thermal conductivity. The real-time dynamic heat loss power is calculated by multiplying the equivalent comprehensive thermal conductivity by the difference, and subtracting the product of the preset estimated value of the comprehensive solar heat gain coefficient of the building window system and the filtered total outdoor solar irradiance.

4. The control system of the intelligent variable frequency air conditioning device based on multi-sensor fusion according to claim 2, characterized in that, The parameter identification module extracts the actual output heating power and identifies the equivalent heat capacity of the building envelope, specifically for: During the unsteady heating phase at the initial stage of system startup, the integral value of the actual output heating power over time is recorded within the set calculation period. Obtain the difference between the filtered infrared radiation temperature of the indoor wall surface at the end of the calculation within the corresponding calculation time period and the filtered infrared radiation temperature of the indoor wall surface at the start of the calculation. The equivalent heat capacity of the building envelope is calculated by dividing the integral value by the difference.

5. The control system of the intelligent variable frequency air conditioning device based on multi-sensor fusion according to claim 2, characterized in that, The airflow control module calculates the gas-solid two-phase temperature gradient in the indoor space and outputs an air delivery vector command to the guide vane stepper motor (70) when the temperature gradient exceeds a preset cold radiation critical threshold. Specifically, it is used for: The temperature gradient is obtained by calculating the difference between the filtered indoor air temperature and the infrared radiation temperature of the indoor wall surface. When the equivalent comprehensive heat transfer conductivity is determined to be greater than the preset heat loss rate threshold and the temperature difference gradient is greater than the preset cold radiation critical threshold, a pulse sequence signal is generated and output to the guide vane stepper motor (70) to drive the guide vane of the air conditioner indoor unit to rotate to the limit deflection angle and form an attached jet.

6. The control system of the intelligent variable frequency air conditioning device based on multi-sensor fusion according to claim 2, characterized in that, The airflow control module calculates and outputs a dynamic weighting coefficient for the air interaction temperature, specifically used for: Obtain the baseline weighting coefficients under normal air supply conditions; Calculate the difference between the temperature gradient between the indoor air and the interior wall surface obtained from the current calculation and the critical threshold of cold radiation, and obtain the ratio of the difference to the critical threshold of cold radiation. The updated dynamic weighting coefficient for air action temperature is calculated by subtracting the product of the preset dynamic correction factor and the ratio from the baseline weighting coefficient.

7. The control system of the intelligent variable frequency air conditioning device based on multi-sensor fusion according to claim 2, characterized in that, The frequency conversion control module calculates the feedforward reference frequency and the feedback fine-tuning frequency, specifically for: Using the real-time dynamic heat loss power as the input index parameter, the preset discrete data mapping table corresponding to the operating frequency and heating power is called to perform a lookup operation to obtain the feedforward reference frequency. The dynamic effect temperature is calculated by weighting and summing the filtered indoor air temperature and the infrared radiation temperature of the indoor wall surface using the aforementioned dynamic weighting coefficient for air effect temperature. The deviation between the user-set target temperature and the dynamic operating temperature is used as an input variable. The proportional-integral-derivative control algorithm is executed to output the feedback fine-tuning frequency.

8. The control system of the intelligent variable frequency air conditioning device based on multi-sensor fusion according to claim 2, characterized in that, The variable frequency control module combines and limits the two factors, then outputs a target operating frequency command to the variable frequency compressor (60), specifically for: The initial synthesized frequency is obtained by adding the feedforward reference frequency and the feedback fine-tuning frequency. When it is determined that the current house is in a state of high heat loss, the clamping upper limit frequency is calculated by multiplying the maximum allowable operating frequency of the variable frequency compressor (60) by a derating factor of less than 1. The initial synthesized frequency is compared with the clamping upper limit frequency, and the smaller value between the two is selected as the final target operating frequency command.

9. The control system of the intelligent variable frequency air conditioning device based on multi-sensor fusion according to claim 2, characterized in that, The defrosting control module compares the thermal balance state and outputs a switching-related command to the four-way valve (90), specifically for: The current sensible heat storage capacity is estimated by calling the equivalent heat capacity and the infrared radiation temperature of the indoor wall surface, and the real-time dynamic heat loss power is multiplied by the system's preset estimated defrosting time to calculate the total heat loss. When it is determined that the sensible heat storage is less than the sum of the total heat leakage and the preset safe heat margin, a delayed reversal command is output to the four-way valve (90), and at the same time, the variable frequency compressor (60) is forced to operate at the clamping upper limit frequency and the guide vane stepper motor (70) is linked to establish the attached jet state for heat storage.

10. The control system of the intelligent variable frequency air conditioning device based on multi-sensor fusion according to claim 2, characterized in that, During the reversing process, the defrosting control module outputs an opening adjustment command to the electronic expansion valve (80), specifically for: During the defrosting cycle, a discrete differential operation is performed on the infrared radiation temperature of the indoor wall surface within the continuous sampling period to obtain the rate of decrease of the current indoor wall surface temperature. The updated opening step command of the electronic expansion valve (80) is calculated by adding the preset positive throttling gain coefficient and the product of the decrease rate of change to the set baseline defrosting opening step number.

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