An intelligent electric energy metering box

Abstract

The present invention discloses an intelligent electric energy metering box, comprising: a power conversion module for converting 380V into 12V and 3.3V power supplies; an electric energy metering module electrically connected to the power conversion module for metering and data processing of the user's electricity consumption; a WIFI radio frequency module electrically connected to the electric energy metering module for transmitting the data of the electric energy metering module to an external main controller; and a system module electrically connected to the power conversion module for dissipating heat and reducing condensation inside the electric energy metering box under specified temperature and humidity conditions. The present invention has the following beneficial effects: This intelligent electric energy metering box can improve the use reliability, extend the service life of the equipment, and ensure the safe and stable operation of the electric energy metering system.

Description

Technical Field

[0001] The present invention relates to the field of electric energy metering, and particularly to an intelligent electric energy metering box. Background Art

[0002] As an important metering device protection device in the power system, the electric energy metering box is mainly used for installing and protecting metering devices such as electric energy meters and circuit breakers. With the advancement of the construction of smart grids, modern electric energy metering boxes not only need to meet basic protection requirements but also need to adapt to the installation needs of intelligent devices. Currently, the electric energy metering boxes on the market are generally made of materials such as metals (galvanized iron, stainless steel) and non-metals (PC, ABS, gold-plastic PC + ABS, SMC fiberglass-reinforced unsaturated polyester molding plastics), and have certain waterproof, dustproof, and corrosion-resistant properties.

[0003] Traditional electric energy metering boxes usually adopt a fully enclosed structure design, and the heat dissipation inside the box body mainly relies on natural convection. Generally, a small number of ventilation holes are provided at the bottom or side of the box body for air circulation. Although this design meets the requirements of the protection level to a certain extent, there are two prominent problems in actual use: unsatisfactory heat dissipation effect and the formation of condensate.

[0004] In terms of heat dissipation, especially in hot summer weather or when the device load is large, the heat generation inside the box body increases significantly. Devices such as electric energy meters and circuit breakers generate a large amount of heat during operation, and it is difficult for these heats to dissipate in a timely manner in a closed space. Due to the limited effect of natural convection and the limitations of the number and size of ventilation holes, the temperature inside the box body continues to rise. The high-temperature environment will accelerate the aging of electronic components, reduce the accuracy of metering devices, and even may affect the normal operation of the devices.

[0005] Another serious problem is the formation of condensate. When the ambient temperature is low (especially when the temperature difference between day and night is large in spring and autumn), the temperature difference between the inside and outside of the box will cause water vapor to condense into water droplets on the inner wall of the box and the surface of components. This phenomenon mainly occurs in the following situations:

[0006] 1. The temperature drops suddenly at night, and the moisture in the air inside the box body condenses during the cooling process;

[0007] 2. When the temperature rises in the early morning, the humid external air enters the relatively cold inside of the box and condenses;

[0008] 3. After the rain, the temperature drops suddenly, and the humid air inside the box condenses when it meets the cold.

[0009] These condensed waters will bring a series of problems: First, the presence of water droplets will increase the risk of electrical equipment short - circuit, threatening the safety of electricity use; Second, long - term water vapor condensation will accelerate the corrosion of metal components, shortening the service life of the equipment; Third, a humid environment is prone to mold growth, affecting the normal operation of the metering device.

[0010] In addition, the existing electric energy metering boxes are not well - designed in dealing with temperature changes. The temperature difference inside and outside the box will cause changes in air pressure. In the case of poor sealing, it is easy for external humid air to invade, exacerbating the condensation problem. At the same time, traditional ventilation and heat - dissipation structures often cannot effectively balance the heat - dissipation needs and the requirements for reducing condensation, and these two goals often restrict each other.

[0011] Therefore, it is of great significance to develop an electric energy metering box that can solve both heat - dissipation and condensation - reduction problems. Such a design not only needs to ensure effective heat - dissipation inside the box but also needs to take measures to slow down the formation of condensed water, which can significantly improve the reliability of the electric energy metering box, extend the service life of the equipment, and ensure the safe and stable operation of the electric energy metering system. Summary of the Invention

[0012] The purpose of the present invention is to provide an intelligent electric energy metering box. This intelligent electric energy metering box can improve the reliability of use, extend the service life of the equipment, and ensure the safe and stable operation of the electric energy metering system.

[0013] The above - mentioned technical purpose of the present invention is achieved through the following technical solutions:

[0014] An intelligent electric energy metering box, comprising: a power conversion module for converting 380V into 12V and 3.3V power supplies; an electric energy metering module electrically connected to the power conversion module for measuring and processing the electricity consumption of users; a WIFI radio - frequency module electrically connected to the electric energy metering module for transmitting the data of the electric energy metering module to an external main controller; a system module electrically connected to the power conversion module for dissipating heat and reducing condensation inside the electric energy metering box under specified temperature and humidity conditions.

[0015] The present invention is further provided as follows: The power conversion module includes: a first step - down conversion circuit, including an MP150GJ - Z controller, whose input terminal is connected to the 380V power supply through a 20Ω current - limiting resistor, and the output terminal is connected to a 1mH power inductor, an ES1J free - wheeling diode, a 1N4007W diode, and a 4.7μF output capacitor to form a 12V output; a second step - down conversion circuit, including an AMS1117S - 3.3 linear voltage regulator, whose input terminal is connected to the 12V output terminal of the first step - down conversion circuit, and after passing through a 0.1μF decoupling capacitor, it is connected to the VIN pin of the voltage regulator, and the VOUT pin of the output terminal outputs a 3.3V voltage.

[0016] The present invention is further configured as: The electric energy metering module includes: a CSE7761 chip having two sets of differential input terminals V1P / V1N and V2P / V2N; a first signal conditioning circuit including a series-connected 5Ω precision resistor, 100Ω resistor, and 330pF capacitor, connected to the V1P / V1N differential input terminal; a second signal conditioning circuit including a series-connected 5Ω precision resistor, 100Ω resistor, and 330pF capacitor, connected to the V2P / V2N differential input terminal; a high-voltage voltage-dividing network composed of four 250kΩ resistors connected in series and then connected in parallel with a 1kΩ resistor and a 33pF capacitor.

[0017] The present invention is further configured as: The WIFI radio frequency module includes: an ESP8266EX chip; a PCB antenna connected to an RF radio frequency switch through a 5.8pF coupling capacitor; the RF radio frequency switch is connected to the radio frequency input terminal of the ESP8266EX chip through a 5.8pF capacitor; a 26MHz crystal oscillator connected to the clock input terminal of the ESP8266EX chip.

[0018] The present invention is further configured as: The system module includes: a first temperature control circuit including a series-connected 1kΩ / 20W NTC thermistor, a first fan, and a permanent magnet with reverse excitation, connected to the 12V output terminal of the power conversion module; a second temperature control circuit including a 10kΩ / 20W NTC thermistor and second and third fans connected in parallel, the 10kΩ / 20W NTC thermistor is connected in series with the second and third fans connected in parallel, and the second temperature control circuit is connected to the 12V output terminal of the power conversion module; an environmental monitoring circuit including a magnetoresistive resistor and a humidity-sensitive resistor, the magnetoresistive resistor and the humidity-sensitive resistor are connected in series with the second and third fans connected in parallel; the environmental monitoring circuit is connected to the 3.3V output terminal of the power conversion module, and the distance between the magnetoresistive resistor and the permanent magnet is 2 - 3mm.

[0019] The present invention is further configured as: The first buck conversion circuit further includes a multi-stage filtering network: the first stage of filtering is composed of a 1mH inductor and a 2.2μF capacitor; the second stage of filtering is composed of a 1nF capacitor; the third stage of filtering is composed of a 220nF capacitor; the fourth stage of filtering is composed of a 220μF electrolytic capacitor; the input terminal of the multi-stage filtering network is connected to the output terminal of the MP150GJ-Z controller, and the output terminal is connected to the 12V output terminal.

[0020] The present invention is further configured as: The second buck conversion circuit further includes an output filtering network: a 1μF capacitor, a 0.1μF capacitor, and a 4.7μF / 16V aluminum electrolytic capacitor are connected in parallel; the input terminal of the output filtering network is connected to the VOUT pin of the AMS1117S-3.3 linear voltage regulator, and the output terminal forms a 3.3V regulated output.

[0021] The present invention is further configured such that the first fan is disposed at the bottom of the power metering box and starts when the temperature exceeds 35°C.

[0022] The present invention is further configured such that the second and third fans are disposed at the bottom or side of the power metering box and start when the temperature exceeds 45°C.

[0023] In summary, the present invention has the following beneficial effects:

[0024] The intelligent power metering box adopts a hierarchical power conversion scheme, realizes efficient buck conversion from 380V to 12V through an MP150GJ-Z controller, and further converts it into a 3.3V power supply using an AMS1117S-3.3 linear voltage regulator to provide a stable and reliable working power supply for each functional module. The design of the multi-stage filtering network significantly improves the power quality, effectively suppresses the power ripple, and ensures the stable operation of the system.

[0025] Based on the dual-channel differential input design of the CSE7761 chip, combined with a precision shunt resistor and an RC low-pass filter circuit, high-precision voltage and current detection are achieved. The metering data output through the serial communication interface can be remotely transmitted and monitored in real time via the WIFI radio frequency module constructed by the ESP8266EX chip, greatly improving the intelligence level and usability of the system.

[0026] The temperature and humidity control system adopts three groups of independent temperature detection and control circuits, controls the start and stop of multiple fans through NTC thermistors with different thresholds, and realizes hierarchical heat dissipation. When the temperature exceeds 35°C, the first fan starts for basic heat dissipation; when the temperature reaches 45°C, the second and third fans are turned on simultaneously to form forced convection heat dissipation, effectively preventing the internal temperature of the box from being too high. At the same time, the composite control circuit composed of a magnetoresistive resistor and a humidity-sensitive resistor can adaptively adjust according to environmental conditions, effectively slowing down the formation of condensed water.

[0027] The intelligent temperature and humidity control scheme not only solves the problem of insufficient heat dissipation of traditional power metering boxes but also effectively prevents the generation of condensed water, significantly extending the service life of the equipment. The overall design not only ensures the metering accuracy and data transmission reliability but also improves the environmental adaptability of the system, achieving a great improvement in the functionality, reliability, and practicality of the intelligent power metering box. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a schematic structural diagram of an intelligent power metering box;

[0029] Figure 2 is a system flow chart of an intelligent power metering box;

[0030] Figure 3Circuit diagram for the 380V - 12V conversion of the power conversion module;

[0031] Figure 4 Circuit diagram for the 12V - 3.3V conversion of the power conversion module;

[0032] Figure 5 Circuit diagram for the electric energy metering module;

[0033] Figure 6 Circuit diagram for the WIFI radio frequency module;

[0034] Figure 7 Circuit diagram for the system module. Detailed implementation mode

[0035] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "page", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation to the present invention.

[0036] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features.

[0037] In the description of the present invention, "a plurality of" means two or more unless otherwise specifically defined. In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed", etc. should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0038] The present invention will be further described in detail below with reference to the accompanying drawings.

[0039] Such as Figure 1 、 Figure 2As shown in the figure, an intelligent electric energy metering box can be a single-phase 4, 6, 9, or 12-meter position box. In this application, taking the single-phase 6-meter position box as an example, it mainly includes a power conversion module. The power conversion module can be uniformly integrated in the total control circuit of the electric energy metering box. The power conversion module converts 380V into available 12V and 3.3V power supplies. The power conversion module is connected to an electric energy metering module. The electric energy metering modules are respectively arranged in each electric energy meter. Through the electric energy metering module, the electricity used by users can be measured and the data can be processed. The electric energy metering module and the power conversion module are connected to a WIFI radio frequency module. Among them, the electric energy metering module and the WIFI radio frequency module are functions of existing electric energy meters, and existing electric energy meters can be used and installed in the electric energy metering box. The WIFI radio frequency module aggregates and transmits the relevant data of the electric energy metering module to an external main controller for summarizing and processing the electricity data. The power conversion module is also connected to a system module. The system module is used to achieve the purpose of cooling the inside of the electric energy metering box and slowing down condensation at specified temperatures and humidities.

[0040] As Figure 3 shown, the power conversion module is a buck converter based on the MP150GJ-Z controller U2, and is set In the main control circuit of the electric energy metering box . The 380V high-voltage input passes through a 20Ω current-limiting resistor R4 from the L terminal, which plays a role in current limiting and protecting, and can also suppress the impact of surge current on the subsequent circuit. The input current passes through a 1N4007 diode D4. The diode can withstand a reverse voltage of 600V, ensuring the reliability of the circuit under large voltage fluctuations.

[0041] The current enters a 1mH power inductor L2, which plays a role in energy storage and release during the switching process. When the internal power transistor at the DRAIN terminal of the MP150GJ-Z controller conducts, L2 stores energy; when the power transistor turns off, L2 discharges energy through D4 to maintain the continuity of the load current. The 4.7μF output capacitor C6 receives the rectified electric energy and filters out the ripple to provide a stable DC voltage for the subsequent stage.

[0042] To obtain a purer output, this application designs a multi-stage filtering network: a 1mH inductor L1 and a 2.2μF capacitor C1 form the main LC filter, a 1nF capacitor C2 is for high-frequency interference, and a 220nF capacitor C3 is used for medium-frequency filtering. A 220μF large-capacity electrolytic capacitor C5 provides main energy storage and low-frequency filtering, and a 0.1μF ceramic capacitor C4 processes high-frequency noise. The above multi-stage filtering combination can effectively suppress electromagnetic interference in a wide frequency band.

[0043] The ES1J freewheeling diode D2 and the 1N4007W diode D3 constitute double protection: D2 provides a freewheeling path for the load, and D3 prevents reverse connection. The 4.7kΩ resistors R1 and R2 form a voltage dividing network to feedback the output voltage information to the FB terminal of the controller to achieve dynamic voltage regulation.

[0044] Through the above settings, the high voltage of 380V is transformed into a low voltage of 12V and output from the VCC terminal, achieving the purpose of converting the high-voltage power supply into a low-voltage power supply.

[0045] As Figure 4 shown, the power conversion module further includes a step-down based on the AMS1117S-3.3 linear voltage regulator U5 Voltage stabilizing circuit. The input voltage of the circuit is input from the VCC terminal through the VIN pin (pin 3) of the voltage regulator. The internal voltage regulation circuit converts the relatively high input voltage into a stable output voltage of 3.3V. A 0.1μF decoupling capacitor C7 is configured at the input terminal to filter out high-frequency interference and ripple of the input power supply and improve the anti-interference ability of the circuit. The output terminal VOUT (pin 2) of the voltage regulator is connected to a three-stage filter capacitor network, including a 1μF capacitor C8 for main filtering, a 0.1μF capacitor C9 for handling high-frequency noise, and a 4.7μF / 16V type A aluminum electrolytic capacitor C21 for providing large-capacity energy storage and low-frequency filtering. This cascaded capacitor configuration can effectively suppress full-band ripple from low frequency to high frequency and ensure the stability of the output voltage. The GND pin (pin 1) is connected to the system ground to provide a stable reference potential.

[0046] Through the low dropout characteristic of the AMS1117S-3.3 voltage regulator above, the 12V voltage at the VCC terminal is converted into a low voltage of 3.3V.

[0047] As Figure 5 shown, the power metering module includes a power metering front-end circuit based on the CSE7761 chip U4. The existing electric energy meter is installed in the electric energy metering box and used after being connected to the main control circuit. The measurement signal is introduced into the circuit input terminal through the CN3 interface, and two groups of differential input channels are adopted. Each channel is configured with a precise voltage division and filtering network: the input signal first undergoes primary shunting through 5Ω precision resistors (R25 / R12 and R15 / R24), and then a RC low-pass filter circuit composed of 100Ω resistors (R10 / R11 and R13 / R14) and 330pF capacitors (C13 / C14 and C15 / C16) is used to suppress high-frequency interference. The signal is sent to the differential input terminals V1P / V1N and V2P / V2N of the CSE7761 chip.

[0048] At the high-voltage input terminal, a high-voltage voltage division network composed of 250kΩ resistors R18 / R19 / R20 / R21 in series is adopted, and a voltage division and filtering circuit is formed in cooperation with a 1kΩ resistor R22 and a 33pF capacitor C19 to condition the high-voltage signal to the level range acceptable to the chip. The CSE7761 chip operates at the 3.3V operating voltage after being converted by the above power supply conversion module, and the power supply of the chip is ensured to be stable through a 0.1μF decoupling capacitor C17 and a 1μF capacitor C18.

[0049] The digital interface part of the chip includes serial communication pins SDI / RX and SDO / TX, and the level matching is carried out through 1kΩ resistors R16 and R17. The clock circuit uses a 3.579545MHz crystal oscillator X2, in cooperation with 22pF load capacitors C22 and C23, to provide an accurate time base signal.

[0050] The above-mentioned power metering module is input into chip U4 after voltage division through the L terminal (high-voltage input terminal), and at the same time, a dual-channel sampling and detection circuit is used to detect voltage and current, so as to calculate the electricity consumption of users. Then, the corresponding data is output through the serial communication pins SDI / RX and SDO / TX and sent to the external main controller for aggregating power information.

[0051] As Figure 6 shown, the WIFI radio frequency module includes a WiFi radio frequency circuit based on the ESP8266EX chip U1, for The existing electric energy meter is installed in the electric energy metering box and used after being connected to the main control circuit. The RF part of the circuit is input from the PCB antenna ANT1 and connected to the RF1 RF switch (HC-RF-IPEX0303-01) through a 5.8pF coupling capacitor C10. The RF switch couples the RF signal to the input terminal of the LNA (low-noise amplifier) of the ESP8266EX through a matching network composed of a 5.8pF capacitor C24 and a 1.5nH inductor L3. This ensures the best transmission efficiency and signal-to-noise ratio of the RF signal.

[0052] The clock circuit uses a 26MHz crystal oscillator X1, and forms an oscillator structure through two 5.6pF load capacitors C11 and C12 to provide an accurate reference clock signal for the ESP8266EX.

[0053] Chip U1 uses a 3.3V regulated power supply converted by a power conversion module, which is decoupled through a 1μF capacitor C20, and the levels of each functional module are pulled up through multiple 12kΩ resistors (R5, R6, R7, R8, R9).

[0054] The GPIO interface of the ESP8266EX is led out through a 7-pin header CN2 for easy external connection. The serial communication interface (SD_CMD, SD_CLK) and the debug interface (CSE_TXD, CSE_RXD) of chip U1 provide data communication functions. Its working status indication is carried out by using LED1 (LED-0805_R) in cooperation with resistor R23 for indication and judgment.

[0055] The above-mentioned WIFI radio frequency module matching network optimizes the signal transmission efficiency, enabling the best performance in receiving and transmitting WiFi signals; the crystal oscillator circuit provides a stable clock source to ensure the accuracy of communication; the perfect decoupling and pull-up circuits guarantee the stable operation of each functional module of the chip; its main function is that the serial communication pins SDI / RX and SDO / TX of the above-mentioned power metering module are connected to the debugging interfaces CSE_TXD and CSE_RXD of chip U1. The corresponding power consumption data is transmitted to the WIFI radio frequency module. Then, the signal is transmitted to the external main controller through chip U1, and then the corresponding user power consumption data is statistically processed.

[0056] As Figure 7 shown, the system module includes a fan control circuit, and the system module is arranged in the electricity energy metering box On one side of the main control circuit, it is connected to the electric energy conversion module. The circuit inputs a 12V voltage from the VCC input terminal and conducts reverse protection through the 1N4007 diode U1. A 100nF decoupling capacitor C25 is configured after the diode U1 to filter out high-frequency interference at the input terminal. The circuit includes three groups of temperature detection and control loops:

[0057] The first path uses a 1kΩ / 20W NTC thermistor R01 to control the fan M1; when the temperature inside the power metering box rises above 35°C, the resistance value of R01 decreases, and at this time, the current value passing through R01 increases, causing M1 to work and the fan to run, dissipating heat inside the power metering box. The fan M1 is set at the bottom of the power metering box.

[0058] The second path uses a 10kΩ / 20W NTC thermistor R02 to control the parallel-connected fans M2 and M3; when the temperature in the power metering box exceeds 45°C, the resistance value of R02 drops to reach the starting current of M2 and M3, causing M2 and M3 to work. M2 and M3 are set at the bottom or side of the power metering box, so that when M2 and M3 work, they cooperate with M1 to improve the heat dissipation efficiency.

[0059] The third path consists of a composite circuit formed by connecting a 1kΩ magnetoresistive sensor MR-R04 and a 10kΩ humidity sensor RH-R03 in series. The third path realizes reducing the impact on the power metering box when water vapor condenses during temperature drop through the above-mentioned composite circuit. Specifically as follows:

[0060] When the temperature drops below 35°C, the resistance values of R01 and R02 recover and the current passing through M1, M2, and M3 is lower than the starting current. At this time, M1, M2, and M3 stop working, and YA-F is a permanent magnet with reverse excitation. Its magnetism decreases as the current increases. When the current passing through YA-F decreases, its magnetism increases.

[0061] Among them, the distance between YA-F and the magnetoresistor R04 is 2-3 mm, so that the magnetic field of the permanent magnet YA-F affects R04. When the magnetism of YA-F increases, the resistance value of R04 decreases due to the influence of the magnetic field intensity of YA-F. At this time, when the humidity inside the electric energy metering box increases, the resistance value of the humidity-sensitive resistor R03 decreases. When it reaches the humidity threshold (this threshold is specifically set according to different regions), at this time, the currents passing through R04 and R03 increase, reaching the starting currents of M2 and M3, causing M2 and M3 to conduct and work, so as to accelerate the convection of the air inside the electric energy metering box in the case of relatively low temperature, thereby alleviating the influence of water vapor condensation in the low-temperature state. When necessary, a corresponding heating resistor can be set between R03 and R04, and the heating resistor can be set on M2 and M3, so that M2 and M3 blow out wind higher than the condensation dew point temperature in the low-temperature state, enhancing the effect of alleviating condensation.

[0062] Under the above settings, when the temperature rises, the internal air convection is adjusted by multiple fans to dissipate heat inside the electric energy metering box. When the temperature drops, the internal air convection can be adjusted by heating or non-heating fans, thereby achieving the effect of slowing down condensation.

[0063] In addition, a 100 nF capacitor C26 is configured at the circuit output end to suppress electromagnetic interference during the switching process.

[0064] The above circuit realizes the precise adjustment of the internal environment of the electric energy metering box through a multi-stage temperature control and intelligent adjustment mechanism. When the temperature exceeds 35 °C, the first-stage fan M1 automatically starts for heat dissipation; when the temperature continues to rise to 45 °C, the second-stage parallel fans M2 and M3 work together to form a multi-stage heat dissipation mechanism, effectively preventing the internal components of the electric energy metering box from being damaged due to high temperature. The system uses an NTC thermistor as the temperature detection element, which has the characteristics of fast response and high sensitivity.

[0065] In a low-temperature environment, through the series composite detection circuit of the magnetoresistor R04 and the humidity-sensitive resistor R03, combined with the reverse excitation characteristic of the permanent magnet YA-F, the intelligent monitoring of the humidity inside the box is realized. When the temperature drop may cause condensation, the system controls the fan operation to generate air convection, effectively suppressing the water vapor condensation phenomenon and protecting the internal electronic components. This design ensures the accuracy of detection through a reasonable component spacing (2-3 mm between YA-F and R04).

[0066] The circuit uses a combination of 1N4007 diodes and decoupling capacitors for input protection and filtering, significantly improving the anti-interference ability and stability of the system. The 100nF capacitor C26 at the output effectively suppresses electromagnetic interference during the switching process, making the system operation more reliable. The overall design realizes the dual environmental regulation of temperature and humidity, with the advantages of simple structure, precise control, and reliable function, and is particularly suitable for the environmental control of power metering devices with strict requirements. Moreover, since the chips inside the power metering box itself have a large computational pressure, which often leads to signal interruption or poor signal connection, this application uses the setting of thermistors and temperature-sensitive resistors, achieving the purpose of not requiring chip data processing and response, and reducing the computational pressure on the chip.

[0067] This design not only solves the heat dissipation problem of traditional power metering boxes in extreme temperatures but also solves the condensation hazard in low-temperature environments, significantly improving the service life and metering reliability of power metering devices.

[0068] This specific embodiment is only an explanation of the present invention and does not limit the present invention. Those skilled in the art can make modifications to this embodiment without creative contributions according to needs after reading this specification, but as long as it is within the scope of the claims of the present invention, it is protected by the patent law.

Claims

1. An intelligent electric energy metering box, characterized in that: include: Power conversion module, used to convert 380V into 12V and 3.3V power; An electric energy metering module, electrically connected to the power conversion module, for metering and data processing of user power consumption; A WIFI radio frequency module is electrically connected to the electric energy metering module and is used to transmit data of the electric energy metering module to an external main controller; A system module, electrically connected to the power conversion module, for achieving heat dissipation and slowing down condensation inside the electric energy meter box under specified temperature and humidity conditions; The system modules include: A first temperature control circuit, comprising a 1kΩ / 20W NTC thermistor and a first fan and a reversely excited permanent magnet connected in series, is connected to a 12V output terminal of the power conversion module; A second temperature control circuit includes a 10kΩ / 20W NTC thermistor and second and third fans connected in parallel, wherein the 10kΩ / 20W NTC thermistor is connected in series with the second and third fans connected in parallel, and the second temperature control circuit is connected to a 12V output terminal of the power conversion module; The environmental monitoring circuit includes a magnetoresistor and a humidity-sensitive resistor, which are connected in series with the second and third fans connected in parallel; the environmental monitoring circuit is connected to the 3.3V output end of the power conversion module, and the distance between the magnetoresistor and the permanent magnet is 2-3mm.

2. The intelligent electric energy meter box according to claim 1, characterized in that: The power conversion module comprises: The first step-down conversion circuit includes an MP150GJ-Z controller, whose input end is connected to a 380V power supply via a 20Ω current limiting resistor, and whose output end is connected to a 4.7μF output capacitor via a 1mH power inductor, an ES1J freewheeling diode, a 1N4007W diode, to form a 12V output; The second buck conversion circuit includes an AMS1117S-3.3 linear regulator, whose input end is connected to the 12V output end of the first buck conversion circuit, and is connected to the VIN pin of the regulator after a 0.1μF decoupling capacitor, and the output end VOUT pin outputs a 3.3V voltage.

3. The intelligent electric energy meter box according to claim 1, characterized in that: The electric energy metering module comprises: The CSE7761 chip has two sets of differential input terminals: V1P / V1N and V2P / V2N; A first signal conditioning circuit, including a 5Ω precision resistor, a 100Ω resistor and a 330pF capacitor connected in series, is connected to the V1P / V1N differential input terminal; A second signal conditioning circuit, including a 5Ω precision resistor, a 100Ω resistor and a 330pF capacitor connected in series, is connected to the V2P / V2N differential input terminal; The high-voltage divider network consists of four 250kΩ resistors in series and a 1kΩ resistor and a 33pF capacitor in parallel.

4. The intelligent electric energy meter box according to claim 1, characterized in that: The WIFI radio frequency module includes: ESP8266EX chip; PCB antenna, connected to the RF switch through a 5.8pF coupling capacitor; The RF switch is connected to the RF input terminal of the ESP8266EX chip through a 5.8pF capacitor; 26MHz crystal oscillator, connected to the clock input terminal of the ESP8266EX chip.

5. The intelligent electric energy meter box according to claim 2, characterized in that: The first step-down conversion circuit further includes a multi-stage filtering network: The first stage of filtering consists of a 1mH inductor and a 2.2μF capacitor; The second stage of filtering is composed of 1nF capacitors; The third stage of filtering is composed of 220nF capacitors; The fourth stage of filtering is composed of 220μF electrolytic capacitors; The input end of the multi-stage filter network is connected to the output end of the MP150GJ-Z controller, and the output end is connected to the 12V output end.

6. The intelligent electric energy meter box according to claim 2, characterized in that: The second buck converter circuit further includes an output filter network: A 1μF capacitor, a 0.1μF capacitor, and a 4.7μF / 16V aluminum electrolytic capacitor are connected in parallel; The input end of the output filter network is connected to the VOUT pin of the AMS1117S-3.3 linear regulator, and the output end forms a 3.3V regulated output.

7. The intelligent electric energy meter box according to claim 1, characterized in that: The first fan is arranged at the bottom of the electric energy meter box and starts when the temperature exceeds 35°C.

8. The intelligent electric energy meter box according to claim 1, characterized in that: The second and third fans are arranged at the bottom or side of the electric energy meter box and are started when the temperature exceeds 45°C.

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