Embedded control method for direct-cooling refrigerator
By using a single defrost sensor and intelligent algorithm in a direct-cooling refrigerator, the problems of low control accuracy and poor environmental adaptability are solved, enabling accurate estimation and adaptive control of dual-temperature zones, thus improving the refrigerator's adaptability and temperature control accuracy under different climatic conditions.
Patent Information
- Application Number
- CN202511993553.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-26
- Publication Date
- 2026-03-03
AI Technical Summary
Existing control methods for direct-cooling refrigerators suffer from low control precision, poor environmental adaptability, limited functionality, and insufficient self-correction capabilities. In particular, they are prone to 'winter shutdown' in low-temperature environments, and sensor drift cannot be detected by the system.
By employing a single defrosting sensor combined with intelligent algorithms, temperature estimation and environmental perception are achieved through a heat exchange model, enabling accurate estimation and adaptive control of dual-temperature zones, dynamic adjustment of compressor start-stop strategies, and sensor status diagnosis and energy efficiency optimization.
It achieves accurate estimation of dual-temperature zones, adaptive sensing of ambient temperature, self-diagnosis of sensor status, and optimization of operating energy efficiency, reducing hardware costs and failure rates, and improving the refrigerator's adaptability and temperature control accuracy under different climatic conditions.
Smart Images
Figure CN121594634A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the technical field of refrigerators, and more particularly to an embedded control method for direct-cooling refrigerators. Background Technology
[0002] As a widely used household refrigeration device, the core control objective of a direct-cooling refrigerator is to maintain the refrigerator compartment and freezer compartment within a set temperature range. To achieve this objective, the refrigerator control system needs to accurately sense the internal temperature or the temperature of key points closely related to it, and control the start and stop of the compressor accordingly.
[0003] 1. Mechanical temperature controller solution: The most traditional existing technology uses a mechanical thermostat. This thermostat's sensing tube is typically fixed to the evaporator surface, and it mechanically controls the opening and closing of contacts by changing the volume of the internal temperature-sensing agent, thus directly starting and stopping the compressor. The main disadvantage of this approach is: Low control precision: Mechanical movements are sluggish and temperature response is slow, resulting in large temperature fluctuations inside the chamber, which is not conducive to the precise preservation of food.
[0004] Poor environmental adaptability: When the ambient temperature is low (such as in winter), the temperature difference between the inside and outside of the refrigerator decreases, reducing the compressor's operating requirements. This may lead to a higher temperature in the refrigerator compartment due to prolonged shutdown (i.e., the "winter shutdown" phenomenon). To solve this problem, users usually need to manually turn on an additional "low-temperature compensation heater," which not only increases energy consumption but also causes inconvenience to users.
[0005] Limited functionality: It cannot achieve advanced functions such as multi-level temperature settings and intelligent defrosting; 2. Simplified single-sensor solution: To reduce costs, the industry is exploring solutions that reduce the number of sensors. For example, one approach proposes using only a single defrost sensor located on the evaporator to control the compressor's start and stop, inferring the internal temperature through a fixed time-temperature relationship or a simple empirical formula. However, a significant drawback of such simplified solutions is: The model is rigid and lacks adaptability: the fixed calculation model cannot adapt to changes in thermodynamic parameters caused by seasonal changes, frequency of door opening and closing, different food loads, and the decline in the insulation performance of the cabinet over the years, resulting in increasingly larger temperature control deviations after long-term use.
[0006] Unable to effectively cope with low-temperature environments: In the absence of ambient temperature sensors or effective environmental sensing algorithms, the system has difficulty reliably identifying low-temperature operating conditions in winter, which can easily lead to "winter shutdown" or require manual intervention from the user.
[0007] Lack of self-calibration and fault tolerance: Sensor performance drift or abnormality cannot be detected by the system, which may lead to continuous control errors.
[0008] To this end, we propose an embedded control method for direct-cooling refrigerators to achieve an optimal balance between cost and performance. Summary of the Invention
[0009] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.
[0010] In view of the problems existing in the above-mentioned embedded control methods for direct-cooling refrigerators, the present invention is proposed.
[0011] Therefore, the purpose of this invention is to provide an embedded control method for direct-cooling refrigerators, which achieves accurate estimation of dual-temperature zones, adaptive sensing of ambient temperature, self-diagnosis of sensor status, and optimization of operating energy efficiency through a single defrost sensor combined with a series of collaborative intelligent algorithms.
[0012] To solve the above-mentioned technical problems, the present invention provides the following technical solution: an embedded control method for a direct-cooling refrigerator, wherein the refrigerator is equipped with a defrost sensor located near the evaporator, comprising the following steps: Acquire the real-time temperature data of the defrosting sensor; Based on a preset heat exchange model, the internal temperatures of the refrigerator compartment and the freezer compartment are simultaneously estimated using the temperature data from the single defrost sensor. The compressor is controlled to start and stop based on the estimated deviation between the refrigerator compartment temperature and the refrigerator set point; Monitor and analyze the compressor start-stop cycle, and dynamically estimate the current ambient temperature range based on the changing trend of shutdown duration; When the estimated ambient temperature remains below the preset low temperature threshold, the forced operation mode is activated: regardless of the current estimated temperature inside the chamber, the compressor is controlled to start and run a complete cycle.
[0013] In a preferred embodiment of the embedded control method for a direct-cooling refrigerator described in this invention, the heat exchange model is a self-calibrating model, and its calibration process includes: During the natural temperature recovery phase after the compressor stops, the initial rate of temperature rise of the defrost sensor is recorded. The initial recovery rate is compared with the baseline recovery rate stored in the model to calculate the attenuation coefficient that reflects the thermal insulation performance of the enclosure. The thermal resistance parameter of the chamber temperature is estimated from the defrost sensor temperature by dynamically adjusting the temperature during the next compressor run using the attenuation coefficient.
[0014] As a preferred embodiment of the embedded control method for a direct-cooling refrigerator described in this invention, the attenuation coefficient is calculated using a recursive averaging algorithm for smoothing, in order to avoid model oscillations caused by single data fluctuations.
[0015] As a preferred embodiment of the embedded control method for a direct-cooling refrigerator described in this invention, the step of dynamically calculating the ambient temperature range based on the trend of off-time variation specifically includes: Continuously record the downtime and runtime of the most recent N complete compressor operating cycles; Calculate the ratio K of average downtime to average uptime; If the ratio K exceeds the first threshold for M consecutive cycles, and the defrosting sensor reaches an equilibrium temperature lower than the second threshold during shutdown, then it is determined that the system has entered a low ambient temperature range.
[0016] As a preferred embodiment of the embedded control method for a direct-cooling refrigerator described in this invention, the duration of the "complete cycle" in the forced operation mode is determined based on the runtime of the last normal cycle before entering the forced mode.
[0017] As a preferred embodiment of the embedded control method for a direct-cooling refrigerator described in this invention, the method further includes a sensor status diagnosis step: During the period when the compressor is running continuously and the power is stable, monitor the temperature change of the defrost sensor. If the change is less than a preset sensitivity threshold within a preset diagnostic time, the sensor response is determined to be abnormal, and the system switches to a backup control strategy based on a fixed time interval.
[0018] As a preferred embodiment of the embedded control method for a direct-cooling refrigerator described in this invention, the method further includes an energy efficiency optimization step: When the estimated ambient temperature is within the comfortable range, a larger temperature control hysteresis is used; When the estimated ambient temperature is in the high or low temperature range, a smaller temperature control hysteresis is used.
[0019] As a preferred embodiment of the embedded control method for a direct-cooling refrigerator described in this invention, the method further includes a defrost trigger determination step: Total compressor running time; During the initial phase after each compressor start-up, the rate of temperature drop of the defrost sensor was monitored; When the cumulative running time reaches the defrost cycle threshold and the rate of decrease is lower than the preset rate threshold, it is determined that the evaporator is frosted and defrosting is required, and the defrosting program is started.
[0020] An embedded refrigerator control system includes: A single defrost sensor is located on or near the evaporator; The microcontroller is electrically connected to the defrosting sensor and has embedded algorithm programs for temperature estimation, environmental judgment and compressor control. The compressor drive circuit, controlled by the microcontroller, is used to execute the start and stop operations of the compressor.
[0021] A direct-cooling refrigerator, wherein neither the refrigerator compartment nor the freezer compartment is equipped with an independent internal temperature sensor.
[0022] The beneficial effects of this invention are as follows: By using a single defrost sensor combined with a series of collaborative intelligent algorithms, this invention achieves accurate estimation of dual-temperature zones, adaptive sensing of ambient temperature, self-diagnosis of sensor status, and optimization of operating energy efficiency. It not only completely replaces mechanical thermostats and additional in-cabin / ambient sensors, reducing hardware costs and failure rates, but also significantly improves the refrigerator's adaptability, temperature control accuracy, and level of intelligence under different climatic conditions. Attached Figure Description
[0023] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein: Figure 1 This is a schematic diagram of the method steps of the embedded control method for a direct-cooling refrigerator according to the present invention. Detailed Implementation
[0024] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
[0025] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.
[0026] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.
[0027] Secondly, the present invention is described in detail with reference to the schematic diagrams. When detailing the embodiments of the present invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not according to the usual scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. In addition, actual fabrication should include three-dimensional spatial dimensions of length, width, and depth.
[0028] Reference Figure 1 An embedded control method for a direct-cooling refrigerator is provided, wherein the refrigerator is equipped with a defrost sensor located near the evaporator, comprising the following steps: Acquire real-time temperature data from the defrost sensor; Based on a preset heat exchange model, the internal temperatures of the refrigerator and freezer compartments are simultaneously estimated using temperature data from a single defrost sensor. The compressor is controlled to start and stop based on the estimated deviation between the refrigerator compartment temperature and the refrigerator set point; Monitor and analyze the compressor start-stop cycle, and dynamically estimate the current ambient temperature range based on the changing trend of shutdown duration; Downtime: The length of time the compressor stops running, which is directly affected by the ambient temperature.
[0029] High ambient temperature → rapid heating inside the chamber → short downtime.
[0030] Low ambient temperature → slow heating inside the chamber → long downtime.
[0031] Dynamic calculation: By analyzing the trend of downtime changes, such as the downtime being extended over several consecutive cycles, and combined with the equilibrium temperature reached by the defrosting sensor during the downtime, the system can indirectly determine whether it is currently in a high-temperature, comfortable, or low-temperature environment.
[0032] Technical objective: To achieve adaptive identification of ambient temperature range without the need for additional environmental sensors, providing a basis for subsequent control strategies such as hysteresis adjustment and forced operation; When the estimated ambient temperature remains below the preset low temperature threshold, the forced operation mode is activated: regardless of the current estimated temperature inside the chamber, the compressor is controlled to start and run a complete cycle.
[0033] The heat exchange model is a self-calibrating model, and its calibration process includes: During the natural temperature recovery phase after the compressor stops, the initial rate of temperature rise of the defrost sensor is recorded. The initial recovery rate is compared with the baseline recovery rate stored in the model to calculate the attenuation coefficient that reflects the thermal insulation performance of the enclosure. The thermal resistance parameter of the chamber temperature is estimated from the defrost sensor temperature by dynamically adjusting the temperature during the next compressor run using the attenuation coefficient.
[0034] Specifically, the calculation of the attenuation coefficient uses a recursive averaging algorithm for smoothing to avoid model oscillations caused by single data fluctuations. The recursive averaging algorithm is used to smooth the attenuation coefficient, which reflects the change in the thermal insulation performance of the box, to avoid frequent oscillations of model parameters due to single measurement fluctuations and to improve the stability of the system. Its core is that it does not require storing all historical data, but can calculate the new average value only by using the average result of the previous time and the current new observation value. The formula for the recursive average algorithm is as follows:
[0035] in: The original attenuation coefficient, calculated based on the initial recovery rate / reference recovery rate, after the nth compressor shutdown cycle. This value directly reflects the change in insulation performance during the current cycle. The new smoothing attenuation coefficient obtained after the nth calculation will be used to adjust the temperature estimation model; The smoothing factor (also known as the forgetting factor) is a pre-defined constant, and 0 < 0. ≤1. Its physical meaning is: The larger the value (e.g., 0.3), the more the algorithm trusts the new observations, the faster the system responds to changes, but the weaker the ability to resist single fluctuations.
[0036] The smaller the value (e.g., 0.1), the more the algorithm relies on historical smoothing values, resulting in a smoother system response and better filtering effect, but the delay in tracking actual changes will increase.
[0037] The specific application process is as follows: 1. After the nth shutdown, measure the current initial recovery rate. ; 2. Calculate the original attenuation coefficient:
[0038] The factory-calibrated reference recovery rate; 3. Smoothing value from the previous time Substituting into the above recursive average formula, the smoothing attenuation coefficient for this calculation is obtained. ; 4. This is used to update the thermal resistance parameters in the temperature estimation model, thereby enabling adaptive correction of the chamber temperature estimate.
[0039] The attenuation coefficient is calculated using a recursive averaging algorithm for smoothing, in order to avoid model oscillations caused by single data fluctuations. Specifically, the steps for dynamically calculating the ambient temperature range based on the trend of downtime include: Continuously record the downtime and runtime of the most recent N complete compressor operating cycles; Calculate the ratio K of average downtime to average uptime; If the ratio K exceeds the first threshold for M consecutive cycles, and the defrosting sensor reaches an equilibrium temperature lower than the second threshold during shutdown, it is determined that the system has entered a low ambient temperature range. Furthermore, the duration of a "full cycle" in the forced operation mode is determined based on the runtime of the last normal cycle before entering the forced mode.
[0040] The method also includes a sensor status diagnosis step: During the period when the compressor is running continuously and the power is stable, monitor the temperature change of the defrost sensor. If the change is less than the preset sensitivity threshold within the preset diagnostic time, the sensor response is determined to be abnormal, and the system switches to a backup control strategy based on a fixed time interval.
[0041] Furthermore, the method also includes energy efficiency optimization steps: When the estimated ambient temperature is within the comfortable range, a larger temperature control hysteresis is used; When the estimated ambient temperature is in the high or low temperature range, a smaller temperature control hysteresis is used.
[0042] Specifically, hysteresis refers to the width of the temperature range controlled by the compressor's start and stop. For example, if the refrigerator compartment is set to 4°C, and the hysteresis is 2°C, then the compressor will start when the temperature rises to 5°C and stop when it drops to 3°C.
[0043] Comfort range: This usually refers to an ambient temperature between approximately 16℃ and 30℃. At this temperature, the temperature difference between the inside and outside of the refrigerator is moderate, and the compressor start-stop cycle is stable. Using a larger hysteresis can extend the start-stop interval, reduce the frequency of compressor start-stop, thereby reducing energy consumption and extending the compressor life.
[0044] High or low temperature range: When the ambient temperature is too high or too low, the refrigerator's heat load changes complexly, increasing the difficulty of temperature control. In this case, using a smaller hysteresis means that the compressor starts and stops more frequently and the temperature control is more precise, which can prevent excessive temperature fluctuations inside the refrigerator and ensure the food preservation effect.
[0045] Technical objective: To achieve a balance between energy saving and food preservation by dynamically adjusting the hysteresis, and to improve the system's self-adaptive capability.
[0046] The method also includes a defrost trigger determination step: Total compressor running time; During the initial phase after each compressor start-up, the rate of temperature drop of the defrost sensor was monitored; When the cumulative running time reaches the defrosting cycle threshold and the rate of decrease is lower than the preset rate threshold, it is determined that the evaporator is frosted and defrosting is required, and the defrosting program is started.
[0047] Specifically, traditional defrosting methods are usually based solely on the compressor's cumulative running time, such as defrosting once every 8 hours of operation, which can easily lead to "over-defrosting" or "under-defrosting".
[0048] This solution is improved by introducing temperature drop rate monitoring as a second condition for defrosting determination.
[0049] If the evaporator is severely frosted, the heat exchange efficiency will decrease, and even if the compressor is running, the evaporator temperature will drop more slowly.
[0050] By monitoring the "temperature drop rate in the initial stage after startup" and combining it with the cumulative running time, it is possible to more accurately determine whether defrosting is truly necessary.
[0051] Technical objective: To achieve on-demand defrosting, reduce ineffective defrosting cycles, save energy, and extend heater life.
[0052] In addition, the present invention also provides an embedded refrigerator control system, including: A single defrost sensor is located on or near the evaporator; The microcontroller is electrically connected to the defrosting sensor and has embedded algorithms for temperature estimation, environmental assessment, and compressor control. The compressor drive circuit, controlled by a microcontroller, is used to execute the start and stop operations of the compressor.
[0053] A type of direct-cooling refrigerator, in which neither the refrigerator compartment nor the freezer compartment is equipped with an independent internal temperature sensor. Specific Implementation The core components of the control system include: Main control chip: It adopts an 8-bit microcontroller (such as the STC8 series), with built-in ADC (analog-to-digital converter) module and Flash memory.
[0055] Temperature sensor: The only temperature sensing element is a negative temperature coefficient (NTC) thermistor defrost sensor, which is closely attached to the surface of the evaporator in the refrigerator compartment to sense the evaporator temperature; Actuator: The compressor is started and stopped by controlling the relay through the microcontroller's I / O port; Human-machine interface: The control panel located on the refrigerator door is used to set the target temperature of the refrigerator compartment, for example, it can be set to three levels: 2℃, 4℃, and 6℃.
[0056] The control method in this embodiment is executed cyclically after the microcontroller is powered on, and the main steps are as follows: 1. Initialization: The system powers on and reads the model parameters stored in Flash, such as the baseline recovery rate. Initial value of smooth attenuation coefficient, various temperature setpoints, etc.; 2. Data Acquisition: The voltage value of the defrost sensor is read through the ADC module and converted into a temperature value. ; 3. Temperature estimation: Call the self-calibrating heat exchange model, based on the current... Based on the model parameters, the internal temperature of the refrigerator compartment and the temperature of the refrigerator compartment are estimated; 4. Compressor control decision: Normal mode: Compares the internal temperature with the user-set temperature; if there is a start-up hysteresis, the compressor starts; if there is a stop-down hysteresis, the compressor stops. The hysteresis is dynamically selected based on the calculated ambient temperature range. Forced operation mode: If the system determines through start-stop cycle analysis that it is in a low ambient temperature range and meets the forced start conditions, then the compressor will be forcibly started to run a complete cycle, regardless of the internal temperature. 5. Model self-calibration: After each compressor shutdown, the attenuation coefficient is calculated and smoothly updated; 6. Auxiliary function judgment: Perform sensor fault diagnosis and defrosting requirement judgment in parallel.
[0057] Example of running: Assuming the refrigerator initially functions normally, after a sudden drop in ambient temperature: After the compressor stops, the temperature inside the chamber rises very slowly, resulting in a significant extension of the downtime. After three consecutive cycles, the system determined that it had entered the low-temperature range; The system will force the compressor to start before the internal temperature reaches the start-up point. During forced operation, monitoring continues. After forced operation ends, the system resumes normal temperature control logic, but the hysteresis used has been automatically switched to a smaller "low temperature range hysteresis" for finer temperature control. At the same time, after each shutdown, the self-calibrating model will calculate a smaller value. (Because the temperature rises slowly), the temperature estimation formula is automatically corrected after smoothing and filtering, so that it can maintain the accuracy of the estimation even in low temperature environments.
[0058] This embodiment utilizes a single defrost sensor, combined with a series of collaborative intelligent algorithms, to achieve accurate estimation of dual-temperature zones, adaptive sensing of ambient temperature, self-diagnosis of sensor status, and optimization of operational energy efficiency. It not only completely replaces mechanical thermostats and additional in-cabin / ambient sensors, reducing hardware costs and failure rates, but also significantly improves the refrigerator's adaptability, temperature control accuracy, and level of intelligence under different climatic conditions.
[0059] It should be noted that 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 preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.
Claims
1. An embedded control method for a direct-cooling refrigerator, wherein the refrigerator is equipped with a defrost sensor located near the evaporator, characterized in that, Includes the following steps: Acquire the real-time temperature data of the defrosting sensor; Based on a preset heat exchange model, the internal temperatures of the refrigerator compartment and the freezer compartment are simultaneously estimated using the temperature data from the single defrost sensor. The compressor is controlled to start and stop based on the estimated deviation between the refrigerator compartment temperature and the refrigerator set point; Monitor and analyze the compressor start-stop cycle, and dynamically estimate the current ambient temperature range based on the changing trend of shutdown duration; When the estimated ambient temperature remains below the preset low temperature threshold, the forced operation mode is activated: regardless of the current estimated temperature inside the chamber, the compressor is controlled to start and run a complete cycle.
2. The embedded control method for a direct-cooling refrigerator according to claim 1, characterized in that: The heat exchange model is a self-calibrating model, and its calibration process includes: During the natural temperature recovery phase after the compressor stops, the initial rate of temperature rise of the defrost sensor is recorded. The initial recovery rate is compared with the baseline recovery rate stored in the model to calculate the attenuation coefficient that reflects the thermal insulation performance of the enclosure. The thermal resistance parameter of the chamber temperature is estimated from the defrost sensor temperature by dynamically adjusting the temperature during the next compressor run using the attenuation coefficient.
3. The embedded control method for a direct-cooling refrigerator according to claim 2, characterized in that: The attenuation coefficient is calculated using a recursive averaging algorithm for smoothing, in order to avoid model oscillations caused by single data fluctuations.
4. The embedded control method for a direct-cooling refrigerator according to claim 3, characterized in that: The specific steps for dynamically calculating the ambient temperature range based on the trend of downtime variation include: Continuously record the downtime and runtime of the most recent N complete compressor operating cycles; Calculate the ratio K of average downtime to average uptime; If the ratio K exceeds the first threshold for M consecutive cycles, and the defrosting sensor reaches an equilibrium temperature lower than the second threshold during shutdown, then it is determined that the system has entered a low ambient temperature range.
5. The embedded control method for a direct-cooling refrigerator according to claim 4, characterized in that: The duration of a "complete cycle" in the forced operation mode is determined based on the runtime of the last normal cycle before entering the forced mode.
6. The embedded control method for a direct-cooling refrigerator according to claim 1, characterized in that: The method also includes a sensor status diagnosis step: During the period when the compressor is running continuously and the power is stable, monitor the temperature change of the defrost sensor. If the change is less than a preset sensitivity threshold within a preset diagnostic time, the sensor response is determined to be abnormal, and the system switches to a backup control strategy based on a fixed time interval.
7. The embedded control method for a direct-cooling refrigerator according to claim 1, characterized in that: The method also includes an energy efficiency optimization step: When the estimated ambient temperature is within the comfortable range, a larger temperature control hysteresis is used; When the estimated ambient temperature is in the high or low temperature range, a smaller temperature control hysteresis is used.
8. The embedded control method for a direct-cooling refrigerator according to claim 1, characterized in that: The method also includes a defrost trigger determination step: Total compressor running time; During the initial phase after each compressor start-up, the rate of temperature drop of the defrost sensor was monitored; When the cumulative running time reaches the defrost cycle threshold and the rate of decrease is lower than the preset rate threshold, it is determined that the evaporator is frosted and defrosting is required, and the defrosting program is started.
9. An embedded refrigerator control system for performing the method as described in any one of claims 1-8, characterized in that, include: A single defrost sensor is located on or near the evaporator; The microcontroller is electrically connected to the defrosting sensor and has embedded algorithm programs for temperature estimation, environmental judgment and compressor control. The compressor drive circuit, controlled by the microcontroller, is used to execute the start and stop operations of the compressor.
10. A direct-cooling refrigerator, characterized in that, The refrigerator includes the embedded refrigerator control system as described in claim 9, wherein neither the refrigerator compartment nor the freezer compartment is equipped with an independent internal temperature sensor.