Intelligent electric meter with power supply filtering function

Abstract

The utility model relates to the technical field of intelligent electric meters, in particular to an intelligent electric meter with a power supply filtering function, which comprises an intelligent electric meter body connected with an external power supply through a direct current input interface circuit. The direct current input interface circuit is electrically connected with a three-level LOD power supply module in the intelligent electric meter body, and the three-level LOD power supply module is used for filtering current input through the direct current input interface circuit and outputting low-ripple high-precision voltage to supply power to the acquisition circuit and the electric meter control circuit. The acquisition circuit is connected with the electric meter control circuit, and the electric meter control circuit is in signal connection with a background server.

Description

Technical Field

[0001] This utility model relates to the field of smart meter technology, and in particular to a smart meter with power filtering function. Background Technology

[0002] Existing smart meters typically use simple DC power supply modules. While these modules can generally meet the power requirements of the meters, they present several significant problems in practical applications. First, traditional DC power supply modules have weak ripple and noise suppression capabilities for input voltage, resulting in output voltages containing considerable ripple and noise. This not only affects the normal operation of the meter's internal circuitry but also reduces the accuracy and reliability of energy measurement. Second, traditional power supply modules have low power supply rejection ratios (PSRR), failing to effectively suppress the impact of input voltage fluctuations on the output voltage, especially in complex electromagnetic environments. Summary of the Invention

[0003] In view of the above-mentioned prior art, the present invention provides a smart meter with power filtering function, which mainly solves the technical problems existing in the background art.

[0004] To achieve the above objectives, the technical solution of this utility model embodiment is implemented as follows:

[0005] A smart meter with power filtering function includes a smart meter body. The smart meter body is connected to an external power source via a DC input interface circuit. The DC input interface circuit is electrically connected to a three-level LOD power supply module inside the smart meter body. The three-level LOD power supply module is used to filter the current input through the DC input interface circuit and output a low-ripple, high-precision voltage to power the acquisition circuit and the meter control circuit. The acquisition circuit is connected to the meter control circuit, and the meter control circuit is connected to a backend server.

[0006] Optionally, the three-stage LOD power supply module includes a primary LDO circuit, a voltage follower, a secondary LDO circuit, and a final LDO circuit. The input terminal of the primary LDO circuit is connected to the DC input interface circuit, and its output terminal is connected to the secondary LDO circuit. The secondary LDO circuit is connected to the voltage follower and the final LDO circuit in sequence. The final LDO circuit outputs a low-ripple, high-precision voltage to power the acquisition circuit and the meter control circuit.

[0007] Optionally, the voltage follower consists of a low-power low-pass filter and a transconductance amplifier.

[0008] Optionally, the first-stage LDO circuit, the second-stage LDO circuit, and the final-stage LDO circuit each include a reference voltage module, an error amplifier, a power adjustment transistor, and a feedback module, wherein the reference voltage module and the feedback module are both connected to the error amplifier, and the error amplifier is connected to the power adjustment transistor.

[0009] Optionally, the acquisition circuit includes a voltage transformer and a current transformer.

[0010] Optionally, the meter control circuit includes a signal processing circuit, an ARM chip, and an AD circuit. The input terminal of the signal processing circuit is connected to the acquisition circuit, and its output terminal is connected to the AD circuit and the ARM chip in sequence. The ARM chip is connected to the backend server via a carrier module.

[0011] Optionally, the carrier module includes a carrier coupling circuit, a carrier modulation and demodulation chip, and a carrier processing circuit. The ARM chip is connected to the carrier modulation and demodulation chip, and the carrier modulation and demodulation chip is sequentially connected to the carrier processing circuit and the carrier coupling circuit. The carrier coupling circuit is coupled to the power line and transmits the carrier signal to the backend server through the power line.

[0012] The beneficial effects of this utility model are as follows: The smart meter with power filtering function provided in this application uses a three-stage LDO power supply module to perform multi-stage filtering and voltage regulation on the input current, significantly improving the stability and accuracy of the output voltage. Specifically, the first-stage LDO circuit in the three-stage LDO power supply module is responsible for initial voltage regulation and filtering, the second-stage LDO circuit further improves the accuracy and stability of the output voltage, the voltage follower is used to filter out reference noise, and the final-stage LDO circuit outputs a low-ripple, high-precision voltage. Through this multi-stage voltage regulation design, this utility model not only effectively solves the ripple and noise problems existing in traditional power supply modules, but also improves the power rejection ratio and response speed, ensuring the stable operation of the smart meter in various complex electromagnetic environments and providing high-precision and low-noise power support. Attached Figure Description

[0013] Figure 1 This is a schematic block diagram of a smart meter with power filtering function according to an embodiment of this application.

[0014] Figure 2 This is a circuit diagram of the three-level LOD power supply module in an embodiment of this application;

[0015] Figure 3 This is a circuit diagram of the first-stage LDO circuit, the second-stage LDO circuit, and the final-stage LDO circuit in the embodiments of this application.

[0016] Explanation of icon numbers:

[0017] 1. DC input interface circuit; 2. Three-level LOD power supply module; 3. Data acquisition circuit; 4. Meter control circuit; 5. Carrier module; 6. Backend server. Detailed Implementation

[0018] The technical solution of this utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this utility model belongs. The terminology used in this specification of this utility model is for the purpose of describing particular embodiments only and is not intended to limit the utility model. In the following description, the expression "some embodiments" refers to a subset of all possible embodiments; however, it should be understood that "some embodiments" can be the same subset or different subsets of all possible embodiments and can be combined with each other without conflict.

[0019] In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention can be practiced without one or more of these details. In other instances, certain technical features well-known in the art have not been described in order to avoid confusion with the present invention.

[0020] It should be understood that this invention can be embodied in various forms and should not be construed as limited to the embodiments set forth herein. Rather, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of this invention to those skilled in the art. Furthermore, the terminology used herein is intended only to describe particular embodiments and is not intended to limit the invention. When used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “compose” and / or “comprising,” when used in this specification, identify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups. When used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0021] It should also be noted that when an element is referred to as being "fixed to" another element, it can be directly attached to the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "inner," "outer," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0022] To fully understand this utility model, a detailed structure will be presented in the following description to illustrate the technical solution proposed by this utility model. Optional embodiments of this utility model are described in detail below; however, in addition to these detailed descriptions, this utility model may have other embodiments.

[0023] Please refer to the attached document. Figures 1 to 3 A smart meter with power filtering function includes a smart meter body. The smart meter body is connected to an external power source through a DC input interface circuit 1. The DC input interface circuit 1 is electrically connected to a three-level LOD power supply module 2 inside the smart meter body. The three-level LOD power supply module 2 is used to filter the current input through the DC input interface circuit 1 and output a low-ripple, high-precision voltage to power the acquisition circuit 3 and the meter control circuit 4. The acquisition circuit 3 is connected to the meter control circuit 4, and the meter control circuit 4 is signal-connected to a background server 6.

[0024] Specifically, its external power supply is typically a battery with a voltage not exceeding 48V. The power supplied by the external power supply is input through the DC input interface circuit 1. The three-stage LOD power supply module 2 is a key part of the smart meter's power management. It performs multi-stage filtering and voltage regulation on the input current, ultimately outputting a low-ripple, high-precision voltage to provide stable power support for the internal acquisition circuit 3 and meter control circuit 4 of the smart meter. The working principle of the three-stage LOD power supply module 2 is as follows: First, the first-stage LOD performs preliminary voltage regulation and filtering, initially stabilizing the input voltage within a relatively wide range and reducing large ripple and noise; then, the second-stage LOD further improves the accuracy and stability of the output voltage, reducing intermediate frequency noise; finally, the third-stage LOD performs final voltage regulation and filtering, ensuring that the output voltage has extremely low ripple and high precision.

[0025] The data acquisition circuit 3 is connected to the meter control circuit 4. These two parts are the core functional modules of the smart meter. The data acquisition circuit 3 is responsible for real-time monitoring and collecting users' electricity consumption data, such as voltage, current, and power, and converting this data into digital signals. The meter control circuit 4 is responsible for processing the collected data, performing tasks such as energy calculation, data storage, and anomaly detection, and transmitting the data to the backend server 6. This enables the smart meter not only to accurately measure users' electricity consumption, but also to realize remote data transmission and electricity management functions, greatly facilitating the operation and management of the power company and the user's electricity experience.

[0026] In one optional implementation, the three-stage LOD power supply module 2 includes a primary LDO circuit, a voltage follower, a secondary LDO circuit, and a final LDO circuit. The input terminal of the primary LDO circuit is connected to the DC input interface circuit 1, and its output terminal is connected to the secondary LDO circuit. The secondary LDO circuit is connected to the voltage follower and the final LDO circuit in sequence. The final LDO circuit outputs a low-ripple, high-precision voltage to power the acquisition circuit 3 and the meter control circuit 4.

[0027] Specifically, the first-stage LDO circuit, as the first stage of the entire power supply module, is responsible for receiving the current from the DC input interface circuit 1 and performing preliminary voltage regulation and filtering. This process can significantly reduce large ripple and noise in the input current, providing a cleaner power foundation for subsequent circuits. Then, the second-stage LDO circuit further improves the accuracy and stability of the output voltage based on the first-stage LDO circuit, further reduces intermediate frequency noise, and makes the output voltage smoother. The final-stage LDO circuit, as the last stage of the power supply module, is responsible for outputting a low-ripple, high-precision voltage, providing high-quality power support for the acquisition circuit 3 and the meter control circuit 4.

[0028] Through this multi-stage voltage regulation design, the three-stage LOD power supply module 2 provides excellent ripple suppression and low noise performance across a wide load range and frequency range. This not only improves the reliability and stability of the internal circuitry of the smart meter but also ensures the accuracy of energy metering. For example, in the low-frequency range, the gain of the amplifier and power transistor is relatively high, and the power supply rejection ratio (PSRR) mainly depends on the PSRR of the reference voltage; in the mid-frequency range, the gain of the amplifier and power transistor gradually decreases, and the contributions of all three are reflected; in the high-frequency range, the PSRR of the loop is mainly determined by the PSRR of the power transistor, with the error amplifier also making a certain contribution.

[0029] Furthermore, the voltage follower consists of a low-power low-pass filter and a transconductance amplifier. The low-pass filter can effectively remove high-frequency noise, while the transconductance amplifier provides the necessary gain to make the output voltage more stable. The design of the voltage follower effectively improves the power supply rejection ratio (PSRR) of the overall power supply module and reduces the impact of power supply ripple on the output voltage.

[0030] In an optional embodiment, the first-stage LDO circuit, the second-stage LDO circuit, and the final-stage LDO circuit each include a reference voltage module, an error amplifier, a power adjustment transistor, and a feedback module, wherein the reference voltage module and the feedback module are both connected to the error amplifier, and the error amplifier is connected to the power adjustment transistor.

[0031] The reference voltage module is one of the core components of an LDO circuit, responsible for generating a stable reference voltage that is independent of temperature and supply voltage variations. This reference voltage serves as a reference for controlling the stability of the output voltage. The reference voltage module is typically implemented using a bandgap reference voltage source, which utilizes the voltage difference between the base and emitter junctions of a transistor to generate a positive temperature coefficient voltage. This positive temperature coefficient voltage is then superimposed on the negative temperature coefficient voltage of the transistor's own base and emitter junction to produce a voltage with a near-zero temperature coefficient.

[0032] An error amplifier is a high-gain amplifier used to detect the difference between the output voltage and a reference voltage and generate a corresponding control signal. The input of the error amplifier is connected to the reference voltage module and the feedback module, and the output is connected to the power regulation transistor. When the output voltage deviates from the reference voltage, the error amplifier generates an error signal, which is used to correct the output voltage by adjusting the conduction state of the power regulation transistor.

[0033] The power regulator is a key component in an LDO circuit, responsible for adjusting the output voltage based on the output signal from the error amplifier. The power regulator is typically a MOSFET or BJT, and its conduction level is changed to adjust the output voltage. When the output voltage is lower than the reference voltage, the power regulator increases its conduction level, resulting in a higher output voltage; conversely, when the output voltage is higher than the reference voltage, the power regulator decreases its conduction level, resulting in a lower output voltage.

[0034] The feedback module is used to feed a portion of the output voltage back to the negative input of the error amplifier, forming a closed-loop control system. The feedback module typically consists of a voltage divider resistor network, which divides the output voltage proportionally before sending it to the error amplifier. This negative feedback mechanism enables the LDO circuit to respond quickly to changes in the output voltage and maintain its stability.

[0035] Taking the primary LDO circuit as an example, after receiving the current from the DC input interface circuit 1, the primary LDO circuit generates a stable reference voltage through the reference voltage module. The error amplifier detects the difference between the output voltage and the reference voltage, generates a control signal, adjusts the conduction level of the power adjustment transistor, initially stabilizes the voltage and filters large ripples and noise in the input current. The output terminal of its power adjustment transistor is connected to the secondary LDO circuit. During the current output to the secondary LDO circuit, the feedback module is used to feed back a portion of the output voltage to the negative input terminal of the error amplifier, forming a negative feedback channel.

[0036] Furthermore, the acquisition circuit 3 includes a voltage transformer and a current transformer, which are used to sample the voltage signal and current signal before they are connected to the electricity meter, respectively.

[0037] Furthermore, the meter control circuit 4 includes a signal processing circuit, an ARM chip, and an AD circuit. The input terminal of the signal processing circuit is connected to the acquisition circuit 3, and its output terminal is connected to the AD circuit and the ARM chip in sequence. The ARM chip is connected to the background server 6 via a carrier module 5.

[0038] The signal processing circuit is used to amplify and filter the output signals of the voltage transformer and the current transformer. For example, a signal processing circuit including the TL082 chip can be used for amplification. The AD circuit converts the analog signal into a digital signal. The digital signal is finally received by the ARM chip and coupled into a carrier signal through the carrier module 5. Then the carrier signal is transmitted to the background server 6.

[0039] Furthermore, the carrier module 5 includes a carrier coupling circuit, a carrier modulation and demodulation chip, and a carrier processing circuit. The ARM chip is connected to the carrier modulation and demodulation chip, and the carrier modulation and demodulation chip is sequentially connected to the carrier processing circuit and the carrier coupling circuit. The carrier coupling circuit is coupled to the power line and transmits the carrier signal to the background server 6 through the power line.

[0040] Specifically, the main function of a carrier coupling circuit is to couple signals onto or from existing power lines. This is because power lines are originally designed for transmitting electrical energy and their design did not take into account the needs of data transmission. Therefore, a carrier coupling circuit is needed to effectively superimpose high-frequency data signals onto the AC power on the power lines without interfering with the normal power supply. Similarly, when receiving data, the carrier coupling circuit is responsible for extracting the superimposed data signal from the power lines.

[0041] The carrier modulation and demodulation chip is one of the core components of the carrier module 5. It is responsible for converting the data sent by the ARM chip into an analog signal that can be transmitted on the power line (i.e., the modulation process), and restoring the received analog signal into the original digital information (i.e., the demodulation process).

[0042] Its workflow is as follows: when the carrier module 5 transmits the carrier, the ARM chip transmits the data to be transmitted to the carrier modulation and demodulation chip. The carrier modulation and demodulation chip converts the data to be transmitted into an analog signal suitable for power line transmission. After optimization by the carrier signal processing circuit, the signal is sent to the carrier coupling circuit, which couples the processed signal to the power line.

[0043] During carrier reception, the carrier coupling circuit extracts the analog signal from the power line. The extracted analog signal is processed by the carrier signal processing circuit, such as filtering and amplification, to improve the signal quality. The processed signal is sent to the carrier modulation and demodulation chip, which converts the analog signal back to the original data. Finally, the recovered data is read and processed by the ARM chip.

[0044] It should be noted that the carrier coupling circuit, carrier modulation and demodulation chip, carrier processing circuit, signal processing circuit, ARM chip, AD circuit and the components used in this application are all known prior art. Those skilled in the art can select and purchase them according to actual needs. This embodiment will not be described in detail here.

[0045] The above are merely specific embodiments of this utility model, but the protection scope of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. The protection scope of this utility model should be determined by the protection scope of the stated claims.

Claims

1. A smart meter with power filtering function, comprising a smart meter body, wherein the smart meter body is connected to an external power source via a DC input interface circuit, characterized in that, The DC input interface circuit is electrically connected to the three-level LOD power supply module inside the smart meter body. The three-level LOD power supply module is used to filter the current input through the DC input interface circuit and output a low-ripple, high-precision voltage to power the acquisition circuit and the meter control circuit. The acquisition circuit is connected to the meter control circuit, and the meter control circuit is connected to the back-end server signal.

2. A smart meter with power filtering function according to claim 1, characterized in that, The three-stage LOD power supply module includes a primary LDO circuit, a voltage follower, a secondary LDO circuit, and a final LDO circuit. The input terminal of the primary LDO circuit is connected to the DC input interface circuit, and its output terminal is connected to the secondary LDO circuit. The secondary LDO circuit is connected to the voltage follower and the final LDO circuit in sequence. The final LDO circuit outputs a low-ripple, high-precision voltage to power the acquisition circuit and the meter control circuit.

3. A smart meter with power filtering function according to claim 2, characterized in that, The voltage follower consists of a low-power low-pass filter and a transconductance amplifier.

4. A smart meter with power filtering function according to claim 3, characterized in that, The primary LDO circuit, secondary LDO circuit, and final LDO circuit all include a reference voltage module, an error amplifier, a power adjustment transistor, and a feedback module. The reference voltage module and the feedback module are both connected to the error amplifier, and the error amplifier is connected to the power adjustment transistor.

5. A smart meter with power filtering function according to claim 1, characterized in that, The acquisition circuit includes a voltage transformer and a current transformer.

6. A smart meter with power filtering function according to claim 1, characterized in that, The meter control circuit includes a signal processing circuit, an ARM chip, and an AD circuit. The input terminal of the signal processing circuit is connected to the acquisition circuit, and its output terminal is connected to the AD circuit and the ARM chip in sequence. The ARM chip is connected to the backend server via a carrier module.

7. A smart meter with power filtering function according to claim 6, characterized in that, The carrier module includes a carrier coupling circuit, a carrier modulation and demodulation chip, and a carrier processing circuit. The ARM chip is connected to the carrier modulation and demodulation chip. The carrier modulation and demodulation chip is connected in sequence to the carrier processing circuit and the carrier coupling circuit. The carrier coupling circuit is coupled to the power line and transmits the carrier signal to the background server through the power line.

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