Micro-miniature ammeter for realizing wide current range based on analog front-end signal conditioning

Abstract

The utility model relates to a miniature ammeter for realizing a wide current range based on analog front-end signal conditioning, and belongs to the field of electric energy metering. The electric meter comprises a signal acquisition module, an analog front-end circuit, an A / D converter, a digital signal processing circuit and the like. The signal acquisition module acquires voltage and current signals of a power grid, the analog front-end circuit performs noise reduction processing on the signals, the A / D converter converts analog signals into digital signals, and the digital signal processing circuit performs power calculation on the signals. The electric meter provided by the utility model has the advantages of simple structure, reliable performance, complete functions and the like, is suitable for various electricity utilization occasions, and has wide application prospects.

Description

Technical Field

[0001] The utility model belongs to the field of electric energy metering, and relates to a micro-meter for realizing a wide current range based on analog front-end signal conditioning. Background Art

[0002] In the field of electric energy metering, traditional induction electric energy meters usually need to be installed together with power distribution equipment, which not only increases the complexity of installation, but also has limitations in terms of space and time. In contrast, rail-mounted electric energy meters are popular because of their flexible and convenient installation. They can be installed through rails, and can significantly save space and installation costs compared with traditional electric meters. Especially in places where single-phase electric meters are densely used, such as units with a large number of people and communities where electric meters are centrally installed, the installation advantages of rail-mounted electric energy meters are particularly obvious.

[0003] However, existing single-phase electric energy meters generally have limitations on the working current load, usually below 72A. With the improvement of residents' living standards, the continuous increase of intelligent devices and facilities with large power, these devices may be in a low-current state for a long time, thus affecting the metering accuracy of the electric meter. And when using electricity at high load or adding additional electrical equipment, the current in the circuit may far exceed the current during normal operation, which will also affect the accurate metering of the electric energy meter. Therefore, in order to safeguard the interests of users and power supply enterprises, the electric energy meter needs to have a wider current metering range.

[0004] In summary, existing electric energy meters have certain deficiencies in terms of installation convenience and wide current range metering, and a micro-meter that can adapt to a wider range of application scenarios and has a wide current metering range is needed. Summary of the Utility Model

[0005] In view of this, the purpose of the utility model is to provide a micro-meter for realizing a wide current range based on analog front-end signal conditioning, which is small in size, convenient to install, and has a wide current range. The electric energy meter not only occupies a small space and has a high level of intelligence, but also has a wider current range for accurate metering.

[0006] To achieve the above purpose, the utility model provides the following technical solutions:

[0007] A micro-meter for realizing a wide current range based on analog front-end signal conditioning, comprising:

[0008] A first power management module 31, connected to an external power supply, for supplying power to a relay drive circuit and a second power management module;

[0009] A second power management module 32, connected to the first power management module, for supplying power to an analog front-end circuit, a metering module, temperature compensation, an LCD driver, and an LCD display panel;

[0010] The third power management module 33 is connected to the second power management module and supplies power to the HPLC module, the register module, the Bluetooth module, the I2C & SPI module, and the storage module;

[0011] The magnetic latching relay 6 is connected to the power grid and is used to disconnect or connect the circuit between the power grid and the signal acquisition module;

[0012] The relay drive circuit 7 is powered by the first power management module and is connected to the magnetic latching relay;

[0013] The signal acquisition module 2 is connected to the power grid and is used to acquire the voltage and current signals of the power grid;

[0014] The temperature compensation module 15 is connected to the signal acquisition module and is used to compensate for the influence of temperature change on signal acquisition;

[0015] The metering module 9 is connected to the signal acquisition module and is used to perform noise reduction processing and power calculation on the voltage and current signals;

[0016] The HPLC module 13 is connected to the third power management module and the storage module and is used to transmit the metering data through the power line;

[0017] The register module 11 is connected to the third power management module and the metering module and is used to store the configuration data of the metering module;

[0018] The Bluetooth module 18 is connected to the third power management module and the storage module and is used to transmit the metering data through Bluetooth;

[0019] The I2C & SPI module 10 is connected to the third power management module and the storage module and is used to communicate data with other devices;

[0020] The RS485 communication drive module 17 is connected to the second power management module and the storage module and is used to communicate data with other devices;

[0021] The LCD driver 14 is connected to the second power management module and the LCD display panel and is used to drive the LCD display panel to display data;

[0022] The LCD display panel 16 is connected to the second power management module and the LCD driver and is used to display the electricity meter information and the metering data.

[0023] Furthermore, the signal acquisition module 2 includes a voltage sampling circuit and a current sampling circuit.

[0024] Furthermore, the voltage sampling circuit includes a voltage-dividing resistor.

[0025] Furthermore, the current sampling circuit includes a current transformer.

[0026] Furthermore, the analog front-end circuit includes an anti-aliasing filter and a programmable gain amplifier.

[0027] Furthermore, the analog front-end circuit is connected to the signal acquisition module 2 and the A / D converter.

[0028] Furthermore, the A / D converter is connected to the analog front-end circuit and the digital signal processing circuit.

[0029] Furthermore, the digital signal processing circuit is connected to the A / D converter and the storage module.

[0030] Furthermore, the digital signal processing circuit is connected to the storage module and the HPLC module 13.

[0031] Furthermore, the digital signal processing circuit is connected to the storage module and the Bluetooth module 18;

[0032] The digital signal processing circuit is connected to the storage module and the I2C & SPI module 10;

[0033] The digital signal processing circuit is connected to the storage module and the RS485 communication driver module 17;

[0034] The LCD driver 14 is connected to the LCD display panel 16;

[0035] The LCD display panel 16 is connected to the LCD driver 14 and the second power management module 32.

[0036] The beneficial effects of the present utility model are as follows: it realizes the miniaturization and intellectualization of the electricity meter, and is convenient for installation, and can achieve the integrated design and centralized management of electricity metering; at the same time, the design of wide-range current metering brings many conveniences to users. For example, when purchasing, users can buy and use the electricity meter of the present utility model, which can not only meet the high-load power consumption and intelligent management requirements, but also occupies a small space, truly achieving convenience and simplicity. On the other hand, it also solves the problem that when users increase electrical equipment or during peak power consumption periods, the maximum load current will exceed the maximum current range of the electricity meter, avoiding the waste of space and cost caused by sacrificing sensitivity to replace a larger current specification meter, and avoiding the influence of the small current state of the intelligent home appliance sleep mode on the accurate metering of the meter, better meeting the market demand.

[0037] Other advantages, objectives and features of the present utility model will be elaborated to some extent in the subsequent description, and to some extent, will be obvious to those skilled in the art based on the study of the following text, or can be taught from the practice of the present utility model. The objectives and other advantages of the present utility model can be achieved and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to make the objectives, technical solutions and advantages of the present utility model clearer, the present utility model will be described in detail and preferably below in conjunction with the accompanying drawings, wherein:

[0039] Figure 1 It is a position and block diagram of the analog front-end circuit in the electric energy metering circuit;

[0040] Figure 2 It is a block diagram of the electric energy meter structure.

[0041] Reference numerals: signal acquisition module 2, on-chip power management module 3, RS485 communication module 4, magnetic latching relay 6, relay drive circuit 7, metering module 9, I2C & SPI module 10, status register 11, storage module 12, HPLC module 13, LCD drive module 14, temperature compensation module 15, LCD display panel 16, RS485 communication drive module 17, Bluetooth module 18, first power management module 31, second power management module 32, third power management module 33. Specific embodiments

[0042] The following uses specific specific examples to illustrate the implementation manners of the present utility model. Those skilled in the art can easily understand other advantages and effects of the present utility model from the content disclosed in this specification. The present utility model can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present utility model. It should be noted that the drawings provided in the following embodiments only schematically illustrate the basic concept of the present utility model. Without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0043] Among them, the drawings are only for illustrative purposes, showing only schematic diagrams, rather than physical diagrams, and cannot be construed as a limitation on the present utility model; in order to better illustrate the embodiments of the present utility model, some components in the drawings will be omitted, enlarged or reduced, and do not represent the dimensions of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0044] In the attached drawings of the embodiments of the present utility model, the same or similar reference numerals correspond to the same or similar components; in the description of the present utility model, it should be understood that if there are terms such as "upper", "lower", "left", "right", "front", "rear", etc. indicating the orientation or positional relationship, it is based on the orientation or positional relationship shown in the attached drawings. It is only for the convenience of describing the present utility model 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. Therefore, the terms describing the positional relationship in the attached drawings are only used for exemplary illustration and cannot be understood as a limitation of the present utility model. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0045] To achieve the above-mentioned utility model purpose, the technical solution adopted by the present utility model is a micro-miniature electric meter with a wide current range, which can measure a large current range, and the maximum current it can accurately measure is 80A; after sampling the current in the power grid, it is subjected to noise reduction processing through an analog front-end circuit, and finally converted into a 24-bit digital signal for the power calculation by the backend digital signal processing (Digital Signal Processing, DSP) circuit.

[0046] Figure 1Schematic diagram of the high-precision analog front-end structure and auxiliary components adopted by the present utility model. During the voltage and current sampling processes, sampling is respectively carried out through voltage division and mutual inductance methods. Moreover, the inductance and resistance components used for sampling have high precision, and appropriate ratios are set to ensure the normal operation of the subsequent analog front-end circuit and minimize the sampling error as much as possible. The sampled signal passes through an anti-aliasing filter to filter out the signals above the passband of the used ADC, ensuring that there is no spectral aliasing during signal processing. Next, the signal enters a configurable programmable gain amplifier (PGA) to amplify the signal to an appropriate size and amplify small signals for high-precision conversion by the Delta-sigma ADC. The amplification multiples of the used PGA are 1, 2, 4, 8, and 16 times. The signal-to-noise ratio (SNR) of the Delta-sigma ADC is 110 dB, the total harmonic distortion (THD) within 50 times is -107 dB, and the input dynamic range (DR) is 90 dB. Therefore, high precision is achieved in the circuit hardware. The present utility model uses a magnetic latching relay with stable on / off at 80 A current. The 24-bit data output by the Delta-Sigma ADC is sent to the subsequent DSP circuit for calculation. Therefore, the micro-miniature watt-hour meter using the present utility model can accurately measure the maximum 80 A current load and the minimum 8 mA current load within one ten-thousandth of the dynamic range, achieving a metering accuracy of 0.5S level.

[0047] As Figure 2 shown, the present utility model discloses a functional structure block diagram of a single-phase rail-mounted watt-hour meter with a wide current range. The second power supply module 32 supplies power to the on-chip power management module 3, metering module 9, temperature compensation module 15, and RS485 communication module driving module 17. The third power supply module 33 supplies power to the I2C & SPI module 10, status register 11, storage module 12, HPLC module 13, and Bluetooth module 18. The RS485 driving module 17, LCD driving module 14, I2C & SPI module 10, Bluetooth module 18, and HPLC module 13 are all connected to the storage module 12 to receive the data inside the storage module. The status register 11 is respectively connected to the I2C & SPI module 10 and the metering module 9. The purpose is to configure the status register 11 through the I2C & SPI module 10, thereby modifying the internal settings of the metering module 9.

[0048] A micro-miniature electric meter with a wide current range based on analog front-end signal conditioning, comprising:

[0049] The first power management module 31, connected to an external power supply, powers the relay drive circuit and the second power management module;

[0050] The second power management module 32, connected to the first power management module, powers the analog front-end circuit, the metering module, the temperature compensation module, the LCD driver, and the LCD panel;

[0051] The third power management module 33, connected to the second power management module, powers the HPLC module, the register module, the Bluetooth module, the I2C & SPI module, and the storage module;

[0052] The magnetic latching relay 6, connected to the power grid, is used to disconnect or connect the circuit between the power grid and the signal acquisition module 2;

[0053] The relay drive circuit 7, powered by the first power management module 31 and connected to the magnetic latching relay 6, is used to drive the magnetic latching relay;

[0054] The signal acquisition module 2, connected to the power grid, is used to acquire the voltage and current signals of the power grid;

[0055] The temperature compensation module 15, connected to the signal acquisition module, is used to compensate for the influence of temperature changes on signal acquisition;

[0056] The metering module 9, connected to the signal acquisition module, is used to perform noise reduction processing and power calculation on the voltage and current signals;

[0057] The HPLC module 13, connected to the third power management module and the storage module, is used to transmit metering data through the power line;

[0058] The register module 11, connected to the third power management module and the metering module, is used to store the configuration data of the metering module;

[0059] The Bluetooth module 18, connected to the third power management module and the storage module, is used to transmit metering data through Bluetooth;

[0060] The I2C & SPI module 10, connected to the third power management module and the storage module, is used to communicate data with other devices;

[0061] The RS485 communication drive module 17, connected to the second power management module and the storage module, is used to communicate data with other devices;

[0062] The LCD driver 14, connected to the second power management module and the LCD display panel 16, is used to drive the LCD display panel to display data;

[0063] The LCD display panel 16, connected to the second power management module and the LCD driver, is used to display the electricity meter information and metering data.

[0064] Further, the signal acquisition module 6 includes a voltage sampling circuit and a current sampling circuit.

[0065] The voltage sampling circuit includes voltage-dividing resistors.

[0066] The current sampling circuit includes a transformer.

[0067] Further, the analog front-end circuit includes an anti-aliasing filter and a programmable gain amplifier.

[0068] The analog front-end circuit is connected to the signal acquisition module 6 and the A / D converter;

[0069] The A / D converter is connected to the analog front-end circuit and the digital signal processing circuit;

[0070] The digital signal processing circuit is connected to the A / D converter and the storage module 15;

[0071] The digital signal processing circuit is connected to the storage module and the HPLC module 13;

[0072] The digital signal processing circuit is connected to the storage module and the Bluetooth module 11;

[0073] The digital signal processing circuit is connected to the storage module and the I2C & SPI module 12;

[0074] The digital signal processing circuit is connected to the storage module and the RS485 driver module 17;

[0075] The LCD driver 14 is connected to the LCD display panel 16;

[0076] The LCD display panel 16 is connected to the LCD driver 14 and the second power management module 32.

[0077] The specific implementation of the signal acquisition module can refer to Figure 1 the shown structural diagram. One end is connected to the grid AC power. After voltage division through voltage-dividing resistors and mutual induction respectively, voltage and current sampling are performed. Subsequently, an anti-aliasing filtering process is carried out to filter out high-frequency noise; then through the PGA, the amplification factor can be adjusted by a program to increase the signal amplitude for better detection and improve the measurement accuracy; after being sent to the Delta-Sigma ADC, the noise in the signal is further reduced through oversampling and noise shaping to achieve a higher resolution. Finally, the output 24-bit digital signal is output to the DSP unit for processing. The PGA and ADC components in the chip have a large dynamic range and high precision. After noise reduction processing on the signal, the SNR can reach 110 dB and the THD can reach -107 dB level. Therefore, the micro small electric energy meter of the present utility model can achieve accurate measurement of a maximum current load of 80 A and a minimum current load of 8 mA within a dynamic range of one ten-thousandth, reaching a measurement accuracy of 0.5S level.

[0078] Among them, the SoC chip is a system-on-chip integrating metering functions, Liquid Crystal Display (LCD) driving, temperature compensation and other functions. The XL7501 SoC chip is adopted for this chip, which has a low-noise and high-precision power management module inside. It integrates a High-speed Power Line Communication (HPLC) and a Bluetooth module inside, and can adapt to various application environments and operation modes. The display module uses a wide-temperature segment LCD display to display power parameters and electric energy values, and at the same time cooperates with the Bluetooth module or the button module for parameter setting. The off-chip communication module is a standard RS485 communication interface, and the communication protocol is DL / T 645-2007. Combining the on-chip broadband power line carrier module and the Bluetooth module, the electric meter can be controlled through wired communication, or data can be transmitted between the smart meter and the smartphone via Bluetooth.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions, and they should all be covered by the scope of the claims of the present invention.

Claims

1. A micro-miniature electric meter based on analog front-end signal conditioning for achieving a wide current range, characterized in that: Comprising: A first power management module (31), connected to an external power supply, for supplying power to the relay drive circuit and the second power management module; A second power management module (32), connected to the first power management module, for supplying power to the analog front-end circuit, the metering module, the temperature compensation, the LCD drive, and the LCD display panel; A third power management module (33), connected to the second power management module, for supplying power to the HPLC module, the register module, the Bluetooth module, the I2C & SPI module, and the storage module; A magnetic latching relay (6), connected to the power grid, for disconnecting or connecting the circuit between the power grid and the signal acquisition module; A relay drive circuit (7), powered by the first power management module and connected to the magnetic latching relay; A signal acquisition module (2), connected to the power grid, for acquiring the voltage and current signals of the power grid; A temperature compensation module (15), connected to the signal acquisition module, for compensating the influence of temperature change on signal acquisition; A metering module (9), connected to the signal acquisition module, for performing noise reduction processing and power calculation on the voltage and current signals; An HPLC module (13), connected to the third power management module and the storage module, for transmitting metering data through the power line; A register module (11), connected to the third power management module and the metering module, for storing the configuration data of the metering module; A Bluetooth module (18), connected to the third power management module and the storage module, for transmitting metering data through Bluetooth; An I2C & SPI module (10), connected to the third power management module and the storage module, for performing data communication with other devices; An RS485 communication drive module (17), connected to the second power management module and the storage module, for performing data communication with other devices; An LCD drive (14), connected to the second power management module and the LCD display panel, for driving the LCD display panel to display data; An LCD display panel (16), connected to the second power management module and the LCD drive, for displaying the electricity meter information and metering data.

2. The miniature electric meter based on analog front-end signal conditioning for achieving a wide current range according to claim 1, wherein: The signal acquisition module (2) includes a voltage sampling circuit and a current sampling circuit.

3. A micro-miniature electric meter based on analog front-end signal conditioning for achieving a wide current range according to claim 2, characterized in that: The voltage sampling circuit includes a voltage dividing resistor.

4. The miniature ammeter based on analog front-end signal conditioning for achieving a wide current range according to claim 2, wherein: The current sampling circuit includes a current transformer.

5. A micro-miniature ammeter based on analog front-end signal conditioning to achieve a wide current range according to claim 1, characterized in that: The analog front-end circuit includes an anti-aliasing filter and a programmable gain amplifier.

6. The miniature ammeter based on analog front-end signal conditioning for achieving a wide current range according to claim 1, wherein: The analog front-end circuit is connected to the signal acquisition module (2) and an A / D converter.

7. A micro-miniature ammeter based on analog front-end signal conditioning to achieve a wide current range according to claim 6, characterized in that: The A / D converter is connected to the analog front-end circuit and a digital signal processing circuit.

8. A micro - miniaturized ammeter based on analog front - end signal conditioning for achieving a wide current range according to claim 7, characterized in that: The digital signal processing circuit is connected to the A / D converter and the storage module.

9. The micro - small ammeter based on analog front - end signal conditioning to achieve a wide current range according to claim 7, wherein: The digital signal processing circuit is connected to the storage module and the HPLC module (13).

10. A micro-miniature electric meter based on analog front-end signal conditioning to achieve a wide current range according to claim 7, characterized in that: The digital signal processing circuit is connected to the storage module and the Bluetooth module (18); The digital signal processing circuit is connected to the storage module and the I2C & SPI module (10); The digital signal processing circuit is connected to the storage module and the RS485 communication drive module (17); The LCD drive (14) is connected to the LCD display panel (16); The LCD display panel (16) is connected to the LCD drive (14) and the second power management module (32).

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