AC / DC electric energy quality analysis recorder

Abstract

The utility model discloses an alternating current and direct current electric energy quality analysis recorder, which comprises a main control board, an integrated acquisition module board and a display board, the integrated acquisition module board is used for acquiring three-phase alternating current input voltage and direct current voltage, and waveform data processed by the integrated acquisition module board is displayed on the display board through the main board, the integrated acquisition module board comprises an alternating-current voltage acquisition unit, a direct-current voltage acquisition unit and a hierarchical storage circuit, the alternating-current voltage acquisition unit is a sampling circuit comprising a voltage transformer and AD7606, the direct-current voltage acquisition unit is an isolation sampling circuit based on AMC1200, and the hierarchical storage circuit is used for storing steady-state data. Synchronous acquisition of alternating current and direct current signals is achieved through the integrated acquisition module, the hierarchical storage structure and anti-interference design are combined, the problems that an existing device is single in function, low in storage efficiency and insufficient in measurement precision are solved, and the system is suitable for real-time monitoring and data storage of scenes such as an electric power system, distributed photovoltaic and charging pile operation and maintenance.

Description

Technical Field

[0001] This utility model relates to the field of AC / DC power quality analysis technology, and in particular to an AC / DC power quality analysis recorder. Background Technology

[0002] Existing power quality analysis recorders (such as CN202410300427.7, etc.) typically only support single AC or DC signal monitoring and have the following drawbacks:

[0003] Separate structure: The AC and DC acquisition modules are designed independently, resulting in large size and high cost;

[0004] Storage redundancy: A single storage unit cannot distinguish between transient events and steady-state data, resulting in low storage space utilization;

[0005] Insufficient interference resistance: High-voltage DC signals are susceptible to common-mode noise interference, making it difficult to guarantee measurement accuracy;

[0006] The DC detection range is narrow (usually <500V), which cannot meet the requirements of high-voltage DC systems. Utility Model Content

[0007] Purpose of the utility model: The purpose of this utility model is to provide an AC / DC power quality analysis recorder, which solves the problems of existing equipment having limited functions, low storage efficiency, and insufficient measurement accuracy.

[0008] Technical Solution: To achieve the above objectives, the present invention provides an AC / DC power quality analysis and recorder, comprising a main control board, an integrated acquisition module board, and a display board. The integrated acquisition module board acquires three-phase AC input voltage and DC voltage, and displays the waveform data processed by the integrated acquisition module board on the display board via the main board. The integrated acquisition module board includes an AC voltage acquisition unit, a DC voltage acquisition unit, and a hierarchical storage circuit. The AC voltage acquisition unit is a sampling circuit including a voltage transformer and an AD7606. The DC voltage acquisition unit is an isolated sampling circuit based on an AMC1200. The hierarchical storage circuit stores steady-state data.

[0009] The motherboard is connected to the integrated acquisition module board via an SPI interface.

[0010] The display panel includes a TFT LCD screen and operation buttons.

[0011] It also includes a power board, a bus board, and a housing. The housing has slots for mounting the source board, main control board, and integrated acquisition module board.

[0012] The inner layer of the shell is covered with a conductive coating to form an electromagnetic shielding shell.

[0013] The integrated acquisition module board uses an STM32F425 microcontroller.

[0014] The AMC1200 DC voltage isolation sampling amplifier circuit consists of a resistor divider, an IN128 differential amplifier, an AMC1200 isolation amplifier, an XTR111 amplifier, and an output circuit.

[0015] The hierarchical storage circuit includes: a ferroelectric memory for storing real-time power parameters and supporting power failure protection; a TF card storage unit for saving fault waveform data in COMTRADE format; and a circular storage area for storing steady-state data at a sampling rate of 1 kHz.

[0016] This also includes common-mode interference suppression design, which involves connecting the three-phase input voltage signal to the voltage transformer via a feedthrough bead and welding a TVS diode to the DC input port.

[0017] Beneficial effects: The present invention has the following advantages: 1. The present invention uses an integrated design of AC / DC power quality analysis recorder AC / DC acquisition module, which reduces the size of the device and the hierarchical storage structure helps to improve data management efficiency;

[0018] 2. The high common-mode rejection ratio isolation amplification and anti-interference structure of the AC / DC power quality analysis recorder described in this utility model ensures the measurement accuracy on the DC side. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of the AC / DC power quality analysis and recording instrument of this utility model;

[0020] Figure 2 This is a schematic diagram of the board connection principle of the AC / DC power quality analysis recorder of this utility model;

[0021] Figure 3 This is a circuit connection diagram of the integrated AC / DC signal acquisition module of the AC / DC power quality analysis and recorder of this utility model;

[0022] Figure 4 This invention relates to the DC voltage isolation sampling and amplification circuit of the AMC1200 AC / DC power quality analysis recorder.

[0023] Figure 5 This is a hardware block diagram of the hierarchical storage module of the AC / DC power quality analysis recorder of this utility model;

[0024] Figure 6 This is a partially enlarged view of the anti-interference structure of the AC / DC power quality analysis recorder of this utility model, including the positions of the TVS tube and the common-mode choke. Detailed Implementation

[0025] The technical solution of this utility model will be described in detail below with reference to the embodiments and accompanying drawings.

[0026] like Figure 1 As shown, the AC / DC power quality analysis recorder of this utility model can be embedded and centrally installed on the panel or cabinet in the control room, or it can be distributed and installed on the switch cabinet.

[0027] The AC / DC power quality analyzer and recorder includes an aluminum housing measuring 96mm*96mm*114mm. Inside, there are four mounting slots for mounting the power board, main control board, and integrated acquisition module board from top to bottom. These are connected via a bus board, which is also connected to the display board.

[0028] like Figure 2 As shown, the motherboard is responsible for data communication and display with the integrated acquisition module board and the display board. It includes a network interface, an RS485 interface, a B-code time synchronization interface, a display driver interface, and an integrated acquisition module board communication SPI interface. The motherboard connects to the integrated acquisition module board through an SPI interface and displays the waveform data processed by the integrated acquisition module board on the TFT LCD screen of the display board.

[0029] The display panel includes a 3.2-inch TFT LCD screen and a set of 6 operation buttons.

[0030] The integrated acquisition module board is the core acquisition unit of the AC / DC power quality analyzer and recorder, accurately acquiring three-phase AC input voltage and DC voltage. The AC signal frequency measurement range is 42.5–57.5 Hz, supporting both star and delta connections. The three-phase input voltage signals are connected to three voltage transformers via through-hole ferrite beads, generating positive and negative 5V small voltage signals.

[0031] like Figure 3 As shown, the integrated data acquisition module board uses the STM32F425 microcontroller as its core, and its peripheral circuits include an isolated power supply, a hierarchical storage circuit, an AC voltage acquisition unit, a DC voltage acquisition unit, an input unit, an output unit, and a communication SPI interface. The AC voltage acquisition unit uses a voltage transformer and an AD7606-based sampling circuit, with a timing error ≤100ns; the DC voltage acquisition unit uses an isolated sampling circuit based on the AMC1200.

[0032] In the DC voltage acquisition unit, the DC voltage input uses an AMC1200 DC voltage isolation amplifier circuit, which isolates and outputs a 4-20mA signal. The microcontroller converts this signal using an LMV358 circuit and then acquires it using an AD7606 to obtain the DC voltage value. Figure 4As shown, the AMC1200 DC voltage isolation sampling amplifier circuit consists of a resistor divider, an IN128 differential amplifier, an AMC1200 isolation amplifier, an XTR111, and an output circuit. It supplies power to the circuit through two 5V outputs with 24V isolation. The size of the voltage divider resistor can be adapted to different voltage ranges, and it can measure DC voltages up to 1000V.

[0033] like Figure 5 As shown, the hierarchical storage circuit includes:

[0034] Ferroelectric memory (FM24C64B): Used to store real-time electrical energy parameters and supports power failure protection;

[0035] TF card storage unit (128GB): Saves fault waveform data (first 200ms + last 400ms) in COMTRADE format;

[0036] Circular storage area: Stores steady-state data at a sampling rate of 1kHz, overwriting the oldest record, and supports continuous operation for up to 30 days.

[0037] The hierarchical storage circuit communicates with the main control chip (STM32F425) of the integrated acquisition module board via the TF card through the SDIO interface. The waveform recording data is stored in FAT32 format, and fault waveform recording data is saved in COMTRADE format to complete the steady-state data storage. The ferroelectric memory saves real-time parameters through the I2C bus and is updated every 5 seconds to complete the transient data storage, ensuring the real-time performance and accuracy of transient data storage.

[0038] like Figure 6 As shown, the AC / DC power quality analysis and recorder also includes a common-mode interference suppression design, specifically: the three-phase input voltage signal is connected to three voltage transformers through a through-hole magnetic bead to improve common-mode interference suppression capability; the DC input terminal ( Figure 6 A TVS diode (SMBJ150CA) is soldered to the DC 750V port. Its cathode is grounded, and its anode is connected to the positive and negative terminals of the DC voltage being measured. The positive and negative terminals of the DC voltage are then connected to the voltage divider resistor network of the isolation amplifier circuit of the AMC1200.

[0039] In addition, the inner layer of the aluminum alloy shell is covered with a conductive coating to form an electromagnetic shielding shell with a grounding impedance of ≤0.1Ω, which effectively reduces electromagnetic interference and ensures stable operation of the equipment.

Claims

1. An AC / DC power quality analysis recorder, characterized by, The application relates to a power quality monitoring device, which comprises a main control board, an integrated acquisition module board and a display board, the integrated acquisition module board collects three-phase alternating current input voltage and direct current voltage, and the waveform data processed by the integrated acquisition module board is displayed on the display board through the main control board, wherein the integrated acquisition module board comprises an alternating current voltage acquisition unit, a direct current voltage acquisition unit and a hierarchical storage circuit, the alternating current voltage acquisition unit is a sampling circuit comprising a voltage transformer and an AD7606, the direct current voltage acquisition unit is an isolated sampling circuit based on AMC1200, and the hierarchical storage circuit stores steady-state data.

2. The AC / DC power quality analysis recorder according to claim 1, characterized in that, The main control board is connected with the integrated acquisition module board through an SPI interface.

3. The AC / DC power quality analysis recorder according to claim 1, characterized in that, The display board comprises a TFT liquid crystal screen and operation buttons.

4. The AC / DC power quality analysis recorder of claim 1, wherein, The device further comprises a power supply board, a bus board and a shell, the shell is internally provided with a card slot for mounting the source board, the main control board and the integrated acquisition module board.

5. The AC / DC power quality analysis recorder according to claim 4, characterized in that, The inner layer of the shell is coated with a conductive coating to form an electromagnetic shielding shell.

6. The AC / DC power quality analysis recorder of claim 1, wherein, The integrated acquisition module board adopts an STM32F425 single-chip microcomputer.

7. The AC / DC power quality analysis recorder of claim 1, wherein, The AMC1200 direct current voltage isolation sampling amplification circuit is composed of a resistance divider, an IN128 differential amplifier, an AMC1200 isolation amplifier, an XTR111 and an output circuit.

8. The AC / DC power quality analysis recorder of claim 1, wherein, The hierarchical storage circuit comprises a ferroelectric memory for storing real-time electric energy parameters and supporting power-off protection, a TF card storage unit for saving fault recording data in a COMTRADE format, and a cyclic storage area for storing steady-state data at a 1kHz sampling rate.

9. The AC / DC power quality analysis recorder of claim 1, wherein, The device further comprises an anti-common-mode interference design, wherein three-phase input voltage signals are connected to the voltage transformer through a through magnetic bead, and a TVS tube is welded on a direct current input port.

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