Intelligent energy-saving commercial refrigerator based on electric wave time service

Abstract

The intelligent energy-saving commercial refrigerator comprises a refrigerator body, an electric wave time service module, a temperature control module, an energy consumption management module and a main control unit, the electric wave time service module, the temperature control module and the energy consumption management module are installed on the refrigerator body, and the electric wave time service module, the temperature control module and the energy consumption management module are in communication connection with the main control unit. The electric wave time service module is used for receiving signal decoding, outputting standard time data and transmitting the signal to the main control unit; the temperature control module executes a time-sharing temperature strategy based on the calibrated time; and the energy consumption management module is used for realizing dynamic power regulation, valley electricity cold storage and fault pre-diagnosis. The electric wave time service module receives long wave signals of the national time service center to achieve high-precision time synchronization, a low-temperature compensation algorithm, dynamic power adjustment and an intelligent temperature control strategy are combined, and the problems of inaccurate temperature control, disordered defrosting period and high energy consumption caused by clock drift of a traditional refrigerator are effectively solved.

Description

Technical Field

[0001] The present invention relates to the technical fields of cold chain equipment and energy-saving technologies, and particularly to an intelligent energy-saving commercial freezer based on radio wave time service. Background Art

[0002] There are many problems in the actual application of traditional commercial freezers, specifically including: Clock deviation problem: Relying on a quartz clock for timing, the daily average deviation can reach ±2 seconds, resulting in an obvious shift in the defrosting cycle (up to ±15 minutes per month), which intensifies the frosting condition of the evaporator, increases the thickness by about 50%, and further leads to a decrease in refrigeration efficiency and a 12%-15% increase in energy consumption.

[0003] Poor temperature control effect: Using a conventional PID algorithm with a fixed control period (usually between 1 and 5 seconds), it is difficult to adapt to scenarios such as frequent opening of the freezer door, resulting in a temperature fluctuation range exceeding ±2°C and unable to meet the requirement of precise temperature control.

[0004] Although some existing improvement solutions attempt to solve these problems, such as using GPS time service, they have defects such as high power consumption (usually >50mA) and poor indoor signal reception effect. Summary of the Invention

[0005] In order to overcome the above problems existing in the prior art, the present invention proposes an intelligent energy-saving commercial freezer based on radio wave time service and its control method.

[0006] The technical solution adopted by the present invention to solve its technical problems is: An intelligent energy-saving commercial freezer based on radio wave time service, including a freezer body and a radio wave time service module, a temperature control module, an energy consumption management module, and a main control unit installed on the freezer body. The radio wave time service module, the temperature control module, and the energy consumption management module are communicatively connected to the main control unit. The radio wave time service module is used to receive signal decoding, output standard time data, and transmit the signal to the main control unit; the temperature control module executes a time-sharing temperature strategy based on the calibrated time; the energy consumption management module is used to achieve dynamic power regulation, valley electricity cold storage, and fault pre-diagnosis.

[0007] For the above-mentioned intelligent energy-saving commercial freezer based on radio wave time service, the energy consumption management module controls the freezer body to switch between a rapid cooling mode, a balanced operation mode, and an energy-saving maintenance mode according to the temperature change rate inside the freezer to achieve dynamic power regulation; through a built-in electricity price time period database, according to the time-sharing electricity price information, the pneumatic precooling cold storage operation is carried out during the low valley electricity price period to achieve valley electricity cold storage; by real-time monitoring of the compressor current, condenser temperature, and evaporator frosting thickness, accurate monitoring of faults is carried out to achieve fault pre-diagnosis.

[0008] The above-mentioned intelligent energy-saving commercial refrigerator based on radio wave time service further includes a metal housing waveguide structure, which is a non-metal window installed on the side wall of the refrigerator body. The radio wave time service module is installed inside the non-metal window. The temperature control module is provided with a low-temperature compensation circuit, and the low-temperature compensation circuit compensates the temperature drift of the crystal oscillator through a cubic polynomial.

[0009] For the above-mentioned intelligent energy-saving commercial refrigerator based on radio wave time service, the specific process of the energy consumption management module to achieve dynamic power adjustment is as follows: when ΔT / Δt > 2°C / min, the compressor operates at 100% power, and at the same time, the fan speed is adjusted to the highest, and it switches to the rapid cooling mode; when 0.5°C / min < ΔT / Δt ≤ 2°C / min, the compressor power is adjusted by frequency conversion, the fan speed is adjusted to medium, and it switches to the balanced operation mode; when ΔT / Δt ≤ 0.5°C / min, the compressor operates at low power, the fan speed is adjusted to the lowest, and it switches to the energy-saving maintenance mode.

[0010] For the above-mentioned intelligent energy-saving commercial refrigerator based on radio wave time service, the temperature control module simultaneously monitors the compressor temperature and the internal temperature of the refrigerator body. When a refrigerator door opening event is detected, the PID control period is automatically shortened to 0.5 seconds.

[0011] For the above-mentioned intelligent energy-saving commercial refrigerator based on radio wave time service, the radio wave time service module continuously senses the long-wave time service signal in the air. After being amplified by a preamplifier and filtered by a band-pass filter, it performs a decoding operation, and transmits the decoded standard time data to the main control unit. The RTC real-time clock module inside the main control unit receives the time data. Every 24 hours, the main control unit compares the received time data with the time recorded by its internal RTC. If the deviation between the two is greater than 1 second, the main control unit automatically corrects the internal RTC.

[0012] The beneficial effect of the present invention is that the present invention realizes high-precision time synchronization with the help of the radio wave time service module, and accurately calibrates the time reference to the millisecond level. Based on this, combined with the dynamic PID control strategy of the temperature control module, it realizes the precise execution of temperature control operations such as defrosting and cold storage in terms of time, effectively avoiding temperature control deviation caused by clock drift, and improving the temperature control accuracy and stability of the refrigerator.

[0013] By adopting the SVPWM variable frequency drive technology to control the compressor, not only the utilization rate of the DC bus voltage is improved, the harmonic loss of the compressor motor is reduced, but also the coefficient of performance (COP) of the compressor is significantly improved, realizing energy efficiency improvement and noise control at the hardware level.

[0014] The dynamic power regulation and valley electricity cold storage strategies in the energy consumption management module can intelligently adjust the operating mode and energy consumption strategy of the refrigerator according to the temperature change in the refrigerator and the time-of-use electricity price information, effectively reducing the energy consumption. In addition, the fault pre-diagnosis system accurately detects common faults by using the random forest algorithm through real-time monitoring of key equipment parameters, improving the operating reliability and maintenance efficiency of the refrigerator. The commercial refrigerator of the present invention is applicable to scenarios such as shopping malls and logistics. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0016] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be described in detail below in conjunction with the drawings and specific embodiments.

[0017] This embodiment discloses an intelligent energy-saving commercial refrigerator based on radio wave time service. The system architecture is as Figure 1 shown, including a refrigerator body and a radio wave time service module, a temperature control module, an energy consumption management module, and a main control unit installed on the refrigerator body. The radio wave time service module, the temperature control module, and the energy consumption management module are communicatively connected to the main control unit.

[0018] Main control unit: It is used to receive data from the radio wave time service module, the temperature control module, and the energy consumption management module, and generate instructions; Radio wave time service module: It is used to receive the 68.5 kHz BPC signal and decode it, output standard time data, and the decoding time data error ≤ 0.5 seconds; Temperature control module: It executes a time-of-use temperature strategy based on the calibrated time, adopts PID control, and the control period is adjustable from 0.5 to 5 seconds; Energy consumption management module: It is used to realize the functions of dynamic power regulation, valley electricity cold storage, and fault pre-diagnosis.

[0019] The collaborative work of the above modules mainly focuses on the collection, transmission, processing of data, and the issuance of control instructions. The modules cooperate closely with each other to form an organic whole.

[0020] In addition, it also includes a metal shell waveguide structure. The metal shell waveguide structure is a non-metal window installed on the side wall of the refrigerator body. The radio wave time service module is installed inside the non-metal window to reduce the shielding effect of the metal shell on the radio wave signal; the temperature control module is provided with a low-temperature compensation circuit. The low-temperature compensation circuit compensates the temperature drift of the crystal oscillator through a cubic polynomial. In a -30°C environment, the monthly cumulative error < 2 seconds.

[0021] In the radio time service module, the magnetic rod antenna receives signals, which are connected to the preamplifier AD8692 via a coaxial cable. Its output is capacitively coupled to a band-pass filter, and the filtered signal is sent to the RX8010SJ decoding chip. The decoded time data is transmitted to the RTC module of the main control unit STM32L476 via the I2C bus to achieve clock calibration.

[0022] In the temperature control module, the DS18B20 transmits the temperature data inside the refrigerator to the SPI interface of the main control unit via a single bus at a certain sampling rate. The PT1000 is also transmitted to the SPI interface after being converted by the MAX31865. The PID controller of the main control unit generates an SVPWM modulation signal based on the temperature data and sends it to the variable frequency compressor drive circuit from the PA8 pin through specific configuration.

[0023] In terms of the energy consumption management module, the dynamic power grading controller calculates the temperature change rate based on the DS18B20 data and transmits it to the main control unit. The valley electricity cold storage strategy sub-module reads the electricity price information from the EEPROM and transmits it to the main control unit. The fault pre-diagnosis system collects key parameters such as the compressor current and transmits them to the main control unit. The main control unit generates control instructions according to the strategy and sends them to the relevant modules, such as adjusting the compressor power according to the temperature change rate, adjusting the PID target temperature and the compressor frequency during valley electricity, triggering an audible and visual alarm when the fault probability is high and transmitting the fault information to the display screen. The main control unit also transmits the operating status information to the display unit via the UART for display, and triggers an audible and visual alarm to remind the user in case of a fault. Through these connections and collaborations of each module, the overall function of the system is realized.

[0024] In this embodiment, the specific collaborations of each module and between modules are as follows: I. System architecture 1. Radio time service module Signal reception link: The magnetic rod antenna receives the 68.5 kHz BPC signal, which is amplified by the AD8692 preamplifier (with the gain set to 60 dB), then filtered by a fourth-order Butterworth filter, and finally decoded by the RX8010SJ chip.

[0025] Anti-metal shielding design: A non-metallic waveguide window (made of polycarbonate, with dimensions of 50 mm × 10 mm) is embedded in the side wall of the metal shell of the refrigerator, and a ferrite magnetic rod antenna is built inside. Through this structural design, the attenuation of the radio wave signal when penetrating the metal shell can be reduced from the conventional 30 dB to about 8 dB, effectively improving the signal reception effect.

[0026] 2. Temperature control module Temperature monitoring mechanism: A dual-temperature sensor setting is adopted, that is, the DS18B20 is used to monitor the temperature inside the refrigerator, and the PT1000 is used to monitor the compressor temperature, realizing real-time and accurate monitoring of the temperatures of different key parts of the refrigerator.

[0027] Dynamic PID Control Strategy: When a freezer door opening event is detected (detected by an infrared sensor), the PID control period is automatically shortened to 0.5 seconds to quickly suppress the temperature fluctuations caused by door opening, so that the internal temperature of the freezer can return to the set temperature range within a short time (≤2 minutes).

[0028] 3. Energy Consumption Management Module Dynamic Power Regulation: According to different situations of the temperature change rate (ΔT / Δt) inside the freezer, different operating modes are automatically switched, specifically including: Rapid Cooling Mode: When ΔT / Δt > 2℃ / min, the compressor operates at 100% power, and at the same time, the fan speed is adjusted to the highest to meet the rapid cooling requirements of the freezer in situations such as a large amount of incoming goods.

[0029] Balanced Operation Mode: When 0.5 < ΔT / Δt ≤ 2℃ / min, the compressor operates at an appropriate power (achieved through variable frequency control), and the fan speed is adjusted to medium to maintain the stability of the internal temperature of the freezer.

[0030] Energy-saving Maintenance Mode: When ΔT / Δt ≤ 0.5℃ / min, the compressor operates at a low power, and the fan speed is adjusted to the lowest to achieve the purpose of energy saving.

[0031] Valley Electricity Cold Storage Strategy: An internal electricity price time period database (which can be manually set or updated through the network) is built. According to the time-of-use electricity price information, pre-cooling and cold storage operations are started during the low valley electricity price period (such as 23:00 - 07:00), and the freezer temperature is pre-cooled to -20℃ in advance. In this way, the start-stop times of the compressor can be effectively reduced during the daytime peak period, thus significantly reducing energy consumption.

[0032] Fault Pre-diagnosis System: Key parameters such as the compressor current, condenser temperature, and evaporator frosting thickness are monitored in real time, and these parameters are analyzed and processed using the random forest algorithm to accurately detect common faults such as refrigerant leakage and ice blockage, with a detection accuracy rate > 90%.

[0033] II. Module Cooperative Work 1. Cooperation between the Radio Wave Time Service Module and the Main Control Unit Time Data Acquisition and Transmission: The magnetic rod antenna in the radio wave time service module continuously senses the 68.5kHz BPC long wave time service signal in the air. After being amplified by the pre-amplifier AD8692 and filtered by the band-pass filter, it is decoded by the RX8010SJ decoding chip.

[0034] The RX8010SJ decoding chip transmits the decoded standard time data (including information such as year, month, day, hour, minute, and second) to the main control unit STM32L476 via the I2C bus according to a specific communication protocol (I2C standard mode, with a rate of 400 kHz). During the transmission process, 33Ω resistors are respectively connected in series to the SCL (clock line) and SDA (data line) on the I2C bus to suppress ringing, and 4.7kΩ pull-up resistors are connected in parallel to 3.3V DVDD to ensure the stability and accuracy of data transmission.

[0035] Clock calibration and synchronization: The RTC real-time clock module inside the main control unit STM32L476 receives the time data from the radio time service module. Every 24 hours, the main control unit compares the received time service data with the time recorded by its own internal RTC. If the deviation between the two is greater than ±1 second, the main control unit will automatically correct the internal RTC. Specifically, it updates the time information by writing to the RTC_BKP_DR register, thereby achieving high-precision time synchronization of the entire system with the national time service center and providing an accurate time reference for subsequent time-based control operations.

[0036] 2. Collaboration between the temperature control module and the main control unit Temperature data acquisition and upload: The temperature sensors DS18B20 (installed at the center of the inner wall of the freezer) and PT1000 (mounted on the compressor housing) in the temperature control module respectively collect the internal temperature of the freezer and the temperature of the compressor in real time.

[0037] DS18B20 adopts the single-wire protocol. Its data line is connected in series with a 220Ω resistor and pulled up to 3.3V. At the same time, the bus capacitance needs to be controlled at ≤100pF to ensure the normal progress of data transmission. It uploads the collected temperature data inside the freezer to the main control unit at a certain sampling rate (which can be flexibly set between 1Hz - 10Hz. Here, it is assumed to collect once every 1 second).

[0038] PT1000 converts the signal through the MAX31865 chip (SPI2 interface, configured in three-wire mode, with a reference resistor Rref = 2kΩ and an accuracy of ±0.05%). After converting the analog temperature signal into a digital signal, it uploads it to the SPI2 interface of the main control unit at a sampling rate of 10Hz.

[0039] Temperature control instruction generation and issuance: The PID controller in the main control unit STM32L476 receives the temperature data from the temperature sensor and combines the preset temperature target value (such as the set temperature of -18°C when the freezer is operating normally, etc.). According to the PID control algorithm, it calculates and generates corresponding control instructions.

[0040] The main control unit sends the generated control instructions in the form of SVPWM modulation signals to the variable-frequency compressor drive circuit in the temperature control module according to specific configuration parameters, so as to achieve precise control of the temperature inside the freezer, enabling the temperature to quickly and stably reach and maintain within the preset target temperature range.

[0041] 3. Collaboration between the energy consumption management module and the main control unit Energy consumption-related data collection and transmission: The dynamic power grading controller in the energy consumption management module analyzes and processes the temperature data uploaded by the temperature control module (especially the temperature change rate ΔT / Δt, obtained by performing differential calculation on the temperature data collected by DS18B20, using sliding window filtering with a window width of 5 seconds and a temperature change rate resolution of 0.1 °C / min) to obtain key information related to energy consumption.

[0042] At the same time, the valley electricity cold storage strategy sub-module in the energy consumption management module reads the time-of-use electricity price table information stored in the EEPROM (AT24C256, I2C2 interface, address 0x50, write cycle <10 ms, data retention >10 years), determines whether it is currently in the low-valley electricity price period (such as 23:00 - 07:00) and corresponding electricity price and other information, and transmits this information to the main control unit.

[0043] In addition, the fault pre-diagnosis system will collect in real time key parameters such as the compressor current (through the ACS712ELCTR-05B Hall sensor, whose output is amplified by OPA376 with a gain of 2 and then connected to ADC1 of the main control unit, i.e., PA1 pin), the condenser temperature difference (collected by a temperature sensor such as PT1000 and transmitted to the main control unit), and the frost thickness on the evaporator (collected by the infrared reflection sensor GP2Y0A21, whose analog signal is input to PA2 pin of the main control unit), and transmit this data to the main control unit.

[0044] Generation and execution of energy consumption control instructions: The main control unit STM32L476 comprehensively analyzes and processes the various data received from the energy consumption management module, including the temperature change rate, electricity price period information, and operating parameters of key equipment, according to the preset energy consumption management strategy.

[0045] For dynamic power grading control, the master control unit determines the current operating mode according to the value of the temperature change rate ΔT / Δt and the preset mode switching threshold (the hysteresis widths for rapid / balanced / energy-saving modes are 0.2 °C / min to prevent frequent switching). For example, when ΔT / Δt > 2 °C / min, it is determined as the rapid mode; when 0.5 < ΔT / Δt ≤ 2 °C / min, it is determined as the balanced mode; when ΔT / Δt ≤ 0.5 °C / min, it is determined as the energy-saving mode. Then, corresponding control instructions are generated and sent to the temperature control module to adjust the compressor power (e.g., 100% power for the compressor and 5000 rpm for the fan in the rapid mode; 70% power for the compressor and 3000 rpm for the fan in the balanced mode; 40% power for the compressor and 1500 rpm for the fan in the energy-saving mode) and the fan speed, achieving dynamic optimization of energy consumption.

[0046] For the valley electricity cold storage strategy, after the master control unit determines that the current time is in the valley electricity price period, it adjusts the target temperature value of the PID controller (e.g., sets the target temperature to -20 °C, 2 °C lower than the conventional -18 °C), and generates corresponding control instructions to send to the temperature control module, making the compressor operate at a specific frequency (e.g., 60 Hz) for a certain time (e.g., 2 hours) for precooling and cold storage operations. After the valley electricity period ends (e.g., at 07:00), the master control unit restores the target temperature of the PID controller to the conventional value (-18 °C), and reasonably adjusts the startup interval of the compressor according to the cold storage situation (e.g., the startup interval of the compressor can be extended to 30 minutes by using cold storage), so as to achieve the purpose of reducing the electricity cost.

[0047] For fault pre-diagnosis, the master control unit inputs the data such as the compressor current, condenser temperature difference, and evaporator frosting thickness received into the edge AI inference engine (deploying the pre-trained random forest model to the MCU using the STM32Cube.AI library) for analysis and processing. The edge AI inference engine classifies and outputs the fault type and the corresponding fault probability according to these data characteristics (e.g., performing FFT analysis on the compressor current, 1024 points, Hamming window, and the normal threshold for harmonic distortion THD < 5%). If the fault probability > 90%, the master control unit will trigger an audible and visual alarm (through the buzzer PB0 pin and the LED PC13 pin), and at the same time, the fault information can be transmitted to the display screen through the UART (PA9 / PA10 pins) for display, so that users can timely understand the operating status of the device and take corresponding maintenance measures.

[0048] The above embodiments are only exemplary embodiments of the present invention and are not used to limit the present invention. Those skilled in the art can make various modifications or equivalent replacements within the essence and protection scope of the present invention, and such modifications or equivalent replacements should also be regarded as falling within the protection scope of the present invention.

Claims

1. An intelligent energy-saving commercial freezer based on radio timekeeping, characterized in that, It includes a freezer body, a radio wave time service module, a temperature control module, an energy consumption management module, and a main control unit installed on the freezer body. The radio wave time service module, the temperature control module, and the energy consumption management module are communicatively connected to the main control unit. The radio wave time service module is used to receive signal decoding, output standard time data, and transmit the signal to the main control unit; the temperature control module executes a time-sharing temperature strategy based on the calibrated time; the energy consumption management module is used to achieve dynamic power regulation, valley electricity cold storage, and fault pre-diagnosis.

2. The intelligent energy-saving commercial refrigerator based on radio time service according to claim 1, wherein The energy consumption management module, according to the temperature change rate inside the freezer, the main control unit controls the freezer body to switch among the rapid cooling mode, the balanced operation mode, and the energy-saving maintenance mode to achieve dynamic power regulation; by building in an electricity price time period database, according to the time-sharing electricity price information, the pre-cooling and cold storage operation is started during the low valley electricity price period to achieve valley electricity cold storage; by real-time monitoring the compressor current, the condenser temperature, and the evaporator frosting thickness, the faults are accurately monitored to achieve fault pre-diagnosis.

3. The intelligent energy-saving commercial freezer based on radio time service according to claim 1, characterized in that, It also includes a metal shell waveguide structure. The metal shell waveguide structure is a non-metal window installed on the side wall of the freezer body. The radio wave time service module is installed inside the non-metal window. The temperature control module is provided with a low-temperature compensation circuit, and the low-temperature compensation circuit compensates the crystal oscillator temperature drift through a cubic polynomial.

4. An intelligent energy-saving commercial freezer based on radio time service according to claim 2, characterized in that, The specific process of the energy consumption management module to achieve dynamic power regulation includes: when ΔT / Δt > 2°C / min, the compressor operates at 100% power, and at the same time the fan speed is adjusted to the highest, and it switches to the rapid cooling mode; when 0.5°C / min < ΔT / Δt ≤ 2°C / min, the compressor power is adjusted by frequency conversion, the fan speed is adjusted to medium, and it switches to the balanced operation mode; when ΔT / Δt ≤ 0.5°C / min, the compressor operates at low power, the fan speed is adjusted to the lowest, and it switches to the energy-saving maintenance mode.

5. An intelligent energy-saving commercial refrigerator based on radio wave timekeeping according to claim 1, characterized in that, The temperature control module simultaneously monitors the compressor temperature and the internal temperature of the freezer body. When a freezer door opening event is detected, the PID control period is automatically shortened to 0.5 seconds.

6. The intelligent energy-saving commercial freezer based on radio time service according to claim 1, characterized in that, The radio wave time service module continuously senses the long-wave time service signal in the air. After being amplified by a pre-amplifier and filtered by a band-pass filter, it performs decoding operations, and transmits the decoded standard time data to the main control unit. The RTC real-time clock module inside the main control unit receives the time data. Every 24 hours, the main control unit compares the received time data with the time recorded by its own internal RTC. If the deviation between the two is greater than 1 second, the main control unit automatically corrects the internal RTC.

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