Voltage monitor and measuring method

Abstract

The invention discloses a voltage monitor and a measurement method. The voltage monitor comprises a power supply management circuit, a sampling amplification circuit, a single-chip microcomputer, a self-adaptive threshold adjustment circuit and a core board. The sampling amplification circuit is connected with the single-chip microcomputer and the self-adaptive threshold adjusting circuit. The sampling amplification circuit comprises a current-limiting resistor connected with a voltage input signal. The mutual inductor is connected with the current-limiting resistor; the sampling resistor is connected with the mutual inductor in parallel; the amplifier is connected with the mutual inductor; the third current-limiting resistor is connected with the amplifier; the reverse input end of the amplifier is connected in parallel with a series combination of a selection switch and a gating resistor of the analog switch; the self-adaptive threshold adjusting circuit is used for selecting a voltage gear and a current gear according to the detected voltage amplitude and current amplitude. The grading signals are calibrated, the calibration coefficient is obtained, and the problem of poor precision measurement of voltage monitors at different positions is solved by selecting a proper measurement interval during measurement.

Description

Technical Field

[0001] This application relates to the field of voltage monitoring, and particularly to a voltage monitor and a measurement method. Background Art

[0002] A voltage monitor is a terminal device that continuously monitors and statistics the operating status of the voltage of a low-voltage grid. According to the technical requirements of the grid, the rated power supply voltages of traditional monitors are 100VAC / 220VAC / 380VAC, and normal operation can be ensured within a relatively wide range of 60VAC to 494VAC. Therefore, the voltage range to be tested is relatively wide, and a high-precision acquisition chip is used to achieve an accuracy of 0.5% for voltage detection. Voltage over-limit is usually an important indicator parameter to measure the power supply quality of a substation area. With the development of power technology, higher requirements are also placed on the power supply quality of the substation area, and intelligent capacitors and on-load voltage regulators have been popularized and applied. To further improve the power supply quality of the substation area, it is necessary to obtain voltage and current data at important nodes as the basis for joint governance and adjustment control. Some manufacturers obtain node voltage and current data through low-voltage intelligent monitoring units, which have also been popularized and applied to a certain extent. With the popularization and application of photovoltaic grid connection, while photovoltaic power stations provide a large amount of clean energy, they also bring certain impacts to the power grid. To balance the transformer outlet voltage and the photovoltaic grid connection point voltage and improve the power supply quality, it is necessary to collect voltage and current information at the monitoring points and calculate relevant parameters in the line.

[0003] Conventional voltage monitors are limited by cost and usually use dedicated chips with a relatively low sampling rate, resulting in relatively low sampling accuracy. Using dedicated chips with a high sampling rate is costly. With the increasing requirements for substation area regulation and control, it is necessary to collect current signals, but most voltage monitors do not have this function. If other monitoring terminals are used to replace current acquisition, the integration degree is relatively low, which is not conducive to large-scale popularization and application. When the substation area voltage monitor receives voltage and current data from other points, the carrier or short-distance wireless module communication method is used, and it is difficult to solve the problem of high data loss rate at points with high load rates or serious blockages. Summary of the Invention

[0004] To solve the above problems, this application proposes a voltage monitor and a detection method. The voltage monitor includes:

[0005] Power management circuit, sampling and amplifying circuit, single-chip microcomputer, adaptive threshold adjustment circuit, core board; the sampling and amplifying circuit is connected to the single-chip microcomputer and the adaptive threshold adjustment circuit, and the sampling and amplifying circuit includes a first current-limiting resistor and a second current-limiting resistor connected to the input signal; a mutual inductor connected to the first current-limiting resistor and the second current-limiting resistor, the mutual inductor being a voltage mutual inductor or a current mutual inductor; a sampling resistor connected in parallel with the mutual inductor; an amplifier connected to the mutual inductor; a third current-limiting resistor connected to the amplifier; the inverting input terminal of the amplifier is connected in parallel with a series combination of a selection switch of an analog switch and a gating resistor; the selection switch includes a first selection switch and a second selection switch, and the gating resistor includes a first gating resistor, a second gating resistor, a third gating resistor, and a fourth gating resistor; the adaptive threshold adjustment circuit is used to select a voltage range and a current range according to the detected voltage amplitude and current amplitude; the core board is connected to the single-chip microcomputer, used to store monitoring data, and perform intranet communication with the power platform.

[0006] In one example, a reference voltage for lifting an AC signal is connected to the IN+ terminal of the amplifier; the VS+ terminal of the amplifier is connected to the positive power supply, and a first filter capacitor and a second filter capacitor are connected in parallel between the amplifier and the positive power supply, and the first filter capacitor and the second filter capacitor are grounded; a clamping and voltage-limiting circuit is further provided at the output terminal of the sampling and amplifying circuit, and the clamping and voltage-limiting circuit includes a clamping and voltage-limiting resistor and a clamping and voltage-limiting diode; the output terminal of the sampling and amplifying circuit is connected to the input terminal of the single-chip microcomputer.

[0007] In one example, the voltage monitor further includes: a switch for controlling the on / off of the adaptive voltage detector; a storage battery for powering and debugging the adaptive voltage detector in the absence of an external power supply; a human-machine interaction interface disposed on the single-chip microcomputer, including a display screen and interactive buttons; a communication interface including a core board modem (modem) module, an external extended modem (modem) module, and an RS485 interface (also known as TIA-485-A, ANSI / TIA / EIA-485, or TIA / EIA-485. RS485 is a standard that defines the electrical characteristics of drivers and receivers in a balanced digital multi-point system, which is defined by the Telecommunications Industry Association and the Electronic Industries Alliance) for communicating with other devices; a debugging port connected to the single-chip microcomputer and the core board for connection and debugging between different devices; the debugging port includes at least one of a USB port, an RS232 port (the full name is the EIA-RS-232C standard, where EIA (Electronic Industry Association) represents the Electronic Industries Association of the United States, RS (recommended standard) represents the recommended standard, and 232 is the identification number), and a network port.

[0008] The present application also provides a measurement method for a voltage monitor, which is applied to the voltage monitor. The method includes: connecting the voltage monitor to a circuit to be detected, and switching the analog switch of the voltage monitor to a preset gear; based on the preset gear, collecting data from the circuit to be detected to obtain the detected voltage and / or detected current of the circuit to be detected; based on the detected voltage and / or the detected current, determining the effective voltage value and / or effective current value of the circuit to be detected.

[0009] In one example, the step of determining the effective voltage value and / or effective current value of the circuit to be detected based on the detected voltage and / or the detected current specifically includes: adjusting the analog switch to a target gear based on the detected voltage and / or the detected current; based on the target gear, collecting data from the circuit to be detected to obtain a corrected voltage and / or corrected current; based on the corrected voltage and / or the corrected current, determining the effective voltage value and / or effective current value of the circuit to be detected.

[0010] In one example, adjusting the analog switch to a target gear based on the detected voltage and / or the detected current specifically includes: performing a fast Fourier transform on the detected voltage and / or the detected current, and invoking the calibration coefficient corresponding to the preset gear to determine the gear determination voltage and / or the gear determination current corresponding to the circuit to be detected; adjusting the analog switch to the target gear based on the gear determination voltage and / or the gear determination current and a preset gear determination threshold.

[0011] In one example, the method further includes: before the voltage monitor leaves the factory, detecting a standard power meter through the voltage monitor to obtain a detection sequence; calibrating the voltage monitor based on the detection sequence.

[0012] In one example, detecting the standard power meter through the voltage monitor to obtain a detection sequence specifically includes: switching the analog switch of the voltage monitor to an initial gear; collecting the standard power meter through a preset sampling frequency to obtain initial detection data; performing a fast Fourier transform on the initial detection data to obtain the detection sequence.

[0013] In one example, calibrating the voltage monitor based on the detection sequence specifically includes: determining the output sequence of the standard power meter; determining the ratio relationship between the output sequence and the detection sequence; using the ratio relationship as the calibration coefficient of the voltage monitor in the initial gear.

[0014] In one example, after using the ratio as the calibration coefficient of the voltage monitor in the initial gear, the method further includes: determining the theoretical output sequence of the standard power meter based on the calibration coefficient and the detection sequence; determining the calibration error corresponding to the calibration coefficient by comparing the theoretical output sequence and the actual output sequence; when the calibration error is lower than a preset error threshold, adjusting the analog switch to other gears until all gears of the voltage monitor are calibrated.

[0015] The voltage monitor and its detection method proposed by the present application can bring the following beneficial effects:

[0016] 1. The present invention solves the problem of low accuracy in voltage and current acquisition with a low-cost solution. A controllable hierarchical switch and a multi-stage signal sampling resistor are introduced on the output side of the voltage and current sensors to amplify strong and weak signals hierarchically, improving the signal-to-noise ratio of voltage and current.

[0017] 2. The microcontroller is used to calibrate the grading signal to obtain the calibration coefficient. During measurement, an appropriate measurement interval is selected in an adaptive manner, solving the problem of poor accuracy measurement of voltage monitors at different positions.

[0018] 3. By means of integrated design and wireless communication, the problems of low success rate in voltage and current acquisition and data transmission of node acquisition are solved, providing a high-precision reference basis for the coordinated control of substation area voltage, improving the stability of power operation in the substation area, and having great practical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings described herein are used to provide a further understanding of the present application and form a part of the present application. The illustrative embodiments and descriptions thereof of the present application are used to explain the present application and do not constitute an improper limitation to the present application. In the drawings:

[0020] Figure 1 is a schematic structural diagram of a voltage monitor in an embodiment of the present application;

[0021] Figure 2 is a schematic diagram of an input signal interface in an embodiment of the present application;

[0022] Figure 3 is a schematic diagram of a voltage sampling and amplifying circuit in an embodiment of the present application;

[0023] Figure 4 is a schematic diagram of a current sampling and amplifying circuit in an embodiment of the present application;

[0024] Figure 5 is a schematic diagram of a partial interface of a microcontroller in an embodiment of the present application;

[0025] Figure 6 is a schematic flowchart of a measurement method of a voltage monitor in an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] To make the objectives, technical solutions, and advantages of the present application clearer, the technical solutions of the present application will be clearly and completely described below in conjunction with the specific embodiments of the present application and the corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0027] The following will describe in detail the technical solutions provided by each embodiment of the present application in conjunction with the drawings.

[0028] Figure 1 is a structural block diagram of a voltage monitor provided by one or more embodiments of this specification. The voltage monitor includes:

[0029] Power management circuit, sampling and amplifying circuit, single-chip microcomputer, adaptive threshold adjustment circuit, core board.

[0030] Among them, the sampling and amplifying circuit is connected to the single-chip microcomputer and the adaptive threshold adjustment circuit. One end of the adaptive threshold adjustment circuit is connected to the single-chip microcomputer, and the other end is connected to the sampling and amplifying circuit, which is used to select the voltage range and current range according to the detected voltage amplitude and current amplitude. The core board is connected to the single-chip microcomputer, which is used to store monitoring data and communicate with the power platform through the intranet.

[0031] As Figure 2 shown is the input signal interface, where P1 is the voltage interface of the three-phase four-wire system of A, B, and C. During detection, the voltage to be measured on the low-voltage side of the substation area is connected to this port. IN_UA is the input signal of the voltage of phase A and also appears on Figure 3 the left side. P2 is connected to the output line of the current transformer, and the transformation ratio of the current transformer is 400:5. It can also be adapted to the existing transformers on the line, and the transformation ratio can be configured in the software parameters.

[0032] Specifically, as Figure 3 and Figure 4 shown, the sampling and amplifying circuit includes a voltage sampling and amplifying circuit corresponding to the voltage transformer (as Figure 3 shown) and a current sampling and amplifying circuit corresponding to the current transformer (as Figure 4 shown). Taking Figure 3 as an example, the sampling and amplifying circuit is described as follows: The voltage sampling and amplifying circuit includes a first current-limiting resistor R3 and a second current-limiting resistor R5 connected to the voltage input signal; a transformer TV1 connected to the first current-limiting resistor R3 and the second current-limiting resistor R5. Based on different sampling data, the transformer TV1 can be divided into a voltage transformer or a current transformer; a sampling resistor R4 connected in parallel with the transformer TV1; an amplifier U2 connected to the transformer TV1; a third current-limiting resistor R2 provided between the amplifier U2 and the transformer TV1; a series combination of a selection switch of the analog switch U3A and a gating resistor connected in parallel to the inverting input terminal of the amplifier; the selection switch includes a first selection switch AU_SEL1 and a second selection switch AU_SEL2, and the gating resistors include a first gating resistor R7, a second gating resistor R8, a third gating resistor R9, and a fourth gating resistor R10. The amplification factor of the sampling and amplifying circuit is selected through pins 9 and 10 of the analog switch U3A, and the amplification factors are shown in the following table:

[0033] AU_SEL1 AU_SEL2 Strobe Resistance Amplification Factor L L R7 6 L H R8 11 H L R9 21 H H R10 31

[0034] The amplification formula is A = 1 + Rx / R6, where Rx is the resistance value of the gating resistor, and can be specifically selected through AU_SEL1 and AU_SEL2.

[0035] In one embodiment, as Figure 3 shown, the amplifier in the sampling and amplifying circuit has five ports, namely IN+ port, IN- port, VS+ port, VS- port, and OUT port. Among them, IN+ and IN- are the non-inverting input terminal and inverting input terminal respectively, V+ and V- are the power supplies of the operational amplifier, and OUT is the output port. In the sampling and amplifying circuit of the present application, a reference voltage for lifting the AC signal, such as a 1.5V reference voltage, is connected to the IN+ terminal of the amplifier to lift the AC signal so that the instantaneous value of the entire AC signal is not less than 0V. At the same time, the VS+ terminal of the amplifier is connected to the positive pole of the power supply, and a first filter capacitor C1 and a second filter capacitor C2 are connected in parallel between the amplifier and the positive pole of the power supply, and the first filter capacitor C1 and the second filter capacitor C2 are grounded. In Figure 3 it, C1 is 10uF and C2 is 100nF.

[0036] A clamping and voltage-limiting circuit for protection is also provided at the output terminal of the sampling and amplifying circuit. The clamping and voltage-limiting circuit includes a clamping and voltage-limiting resistor R6 and a clamping and voltage-limiting diode D1; the output terminal of the sampling and amplifying circuit is connected to the input terminal of the single-chip microcomputer. When the voltage is too high, clamping and voltage-limiting are performed through D1.

[0037] When the sampling and amplifying circuit is a current sampling and amplifying circuit, then as Figure 4 shown, TV4 is a current transformer, the sampling resistor R33 is 100Ω, U8 is an amplifier, U9A is an analog switch, and Y0, Y1, Y2, and Y3 are selected through AI_SEL1 and AI_SEL2. The corresponding current amplification parameter table is as follows,

[0038] AI_SEL1 AI_SEL2 Strobe Resistance Amplification Factor L L R34 17 L H R36 13 H L R38 9 H H R40 5

[0039] The amplification formula is A = 1 + Rx / R35, and Rx is selected through AI_SEL1 and AI_SEL2. D4 plays a protective role. When the sampling voltage is too high, clamping and voltage-limiting are performed through D4, and ADC_IA is connected to the AD input pin of the single-chip microcomputer. It should be noted that the amplification factors in the above two tables are related to the resistance values of the selected resistors, and the amplification factors are not fixed values and can be adjusted based on different selected resistor resistance values.

[0040] In one embodiment, as Figure 1As shown, the voltage monitor further includes: a switch for controlling the on / off of the adaptive voltage detector; a storage battery for powering and debugging the adaptive voltage detector in the absence of an external power supply. The storage battery can use a lithium iron phosphate battery with 6.4V 3Ah. After the power outage, the device can maintain operation for no less than 2 hours. A human-machine interaction interface is set on the single-chip microcomputer, including a display screen and interactive buttons, which can perform functions such as querying collected data and setting the device. A communication interface is set on the core board for communicating with other voltage monitors. The communication interface includes a core board modem module, an extended modem board, and an RS485 communication interface (also known as TIA-485-A, ANSI / TIA / EIA-485, or TIA / EIA-485. RS485 is a standard defining the electrical characteristics of drivers and receivers in a balanced digital multi-point system, defined by the Telecommunications Industry Association and the Electronic Industries Alliance). A debugging port is connected to the single-chip microcomputer and the core board for connection and debugging between different devices. The debugging port includes at least one of a USB port, an RS232 port (the full name is the EIA-RS-232C standard, where EIA represents the Electronic Industry Association of the United States, RS represents the recommended standard, and 232 is the identification number), and a network port. The AC data signal is isolated by current and voltage transformers, then sampled and amplified and enters the single-chip microcomputer. Through the internal logic operation of the single-chip microcomputer, relevant data such as current and voltage are calculated. The single-chip microcomputer is connected to the core board through a serial port.

[0041] As Figure 5 Shown is a schematic diagram of some interfaces of the single-chip microcomputer. On the left are the acquisition ports, which are respectively used to acquire the voltage and current information of the three signal input ports of ABC. On the right are the analog switch selection ports, which are used to select different gating resistors.

[0042] As Figure 6 As shown, the present application also discloses a measurement method applied to the above voltage monitor, including:

[0043] S101: Connect the voltage monitor to the circuit to be detected, and switch the analog switch of the voltage monitor to a preset gear.

[0044] First, connect the voltage monitor to the circuit to be detected. At the same time, to ensure the safety of the voltage monitor device, switch the analog switch to a preset gear. Generally, the preset gear is the minimum gear.

[0045] S102: Based on the preset gear, perform data acquisition on the circuit to be detected to obtain the detection voltage and / or detection current of the circuit to be detected.

[0046] Perform data acquisition on the circuit to be detected through the preset gear. Based on the detection target or the type of the circuit to be detected, the data acquisition result may be the detection voltage, the detection current, or both the detection voltage and the detection current. Generally, the data acquisition mentioned here refers to the acquisition of one-cycle data of the voltage to be detected.

[0047] S103: Based on the detection voltage and / or the detection current, determine the effective voltage and / or effective current of the circuit to be detected.

[0048] After obtaining the monitored voltage or the detection current, the effective voltage and / or effective current corresponding to the current circuit to be detected can be determined based on the monitored voltage and / or the detection current. After obtaining the effective voltage, effective current, and the corresponding phase angle data, relevant data such as voltage, current, active power, reactive power, apparent power, power factor, daily statistics, and monthly statistics for 10 cycles, 1 second, and 1 minute can be calculated based on the above effective voltage, effective current, and phase angle.

[0049] Now, an explanation will be given on how to determine the effective voltage and / or effective current of the circuit to be detected through the detection voltage and / or the detection current. Taking the determination of the effective voltage through the detection voltage as an example, after determining the detection voltage, the analog switch of the adaptive voltage detector can be adjusted to the target gear based on the detection voltage. The target gear here refers to the gear that is more suitable for the detection voltage obtained from the preset gear. Then, based on the target gear, perform data acquisition on the circuit to be detected to obtain the corrected voltage collected by the circuit to be detected at the target gear. Finally, based on the corrected voltage, the voltage at the monitoring point of the voltage monitor in the circuit to be detected can be determined.

[0050] Furthermore, when determining the target gear based on the detection voltage, first, a fast Fourier transform needs to be performed on the detection voltage, and based on the calibration coefficient corresponding to the preset gear, determine the gear determination voltage corresponding to the detection voltage. Then, based on the gear determination voltage and the preset gear determination threshold, determine the target gear corresponding to the detection voltage.

[0051] In one embodiment, before using the voltage monitor, the voltage monitor needs to be calibrated to determine the calibration coefficients corresponding to different gears in the voltage monitor. When calibrating, before the voltage monitor leaves the factory, the standard power meter can be detected through the adaptive monitor to obtain the detection sequence corresponding to the voltage monitor, and then the voltage monitor can be calibrated based on the detection sequence.

[0052] Further, before obtaining the detection sequence, the analog switch of the voltage monitor needs to be switched to the initial gear, which can be any gear. Then, the standard power meter is collected at a preset sampling frequency to obtain the initial detection data, and the detection sequence is obtained by performing a fast Fourier transform on the initial detection data. Usually, the preset sampling frequency is 3.2K, and the detection sequence includes the amplitudes and phases of the voltage fundamental wave, current fundamental wave, and each harmonic wave.

[0053] In one embodiment, after obtaining the monitoring sequence, when calibrating the voltage monitor based on the detection sequence, first, the output sequence of the standard power meter needs to be determined, and then the ratio relationship between the output sequence and the detection sequence is determined, and the ratio relationship can be used as the calibration coefficient of the voltage monitor in the initial gear.

[0054] Further, after determining the calibration coefficient of the initial gear, the calibration coefficient needs to be verified, and the calibration of other gears needs to be completed. Specifically, based on the calibration coefficient and the detection sequence, the theoretical output sequence of the standard power meter is determined, and then by comparing the theoretical output sequence and the actual output sequence, the calibration error corresponding to the calibration coefficient is determined. When the calibration error is lower than the preset error threshold, the analog switch is adjusted to other gears until the calibration of all gears of the voltage monitor is completed.

[0055] The various embodiments in this application are all described in a progressive manner. For the same or similar parts among the various embodiments, reference can be made to each other. Each embodiment focuses on the differences from other embodiments. In particular, for the device and medium embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and reference can be made to the corresponding parts of the method embodiments for the relevant parts.

[0056] The devices and media provided in the embodiments of this application correspond one-to-one with the methods. Therefore, the devices and media also have beneficial technical effects similar to those of their corresponding methods. Since the beneficial technical effects of the methods have been described in detail above, the beneficial technical effects of the devices and media will not be elaborated here.

[0057] Those skilled in the art should understand that the embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, this application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk memories, CD-ROMs, optical memories, etc.) containing computer-usable program codes.

[0058] This application is described with reference to the flowcharts and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the present application. It should be understood that each flow and / or block in the flowchart and / or block diagram can be implemented by computer program instructions, and the combination of the flows and / or blocks in the flowchart and / or block diagram can also be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate means for implementing the functions specified in one or more of the flows Figure 1 one or more of the flows and / or blocks Figure 1 or means for implementing the functions specified in one or more of the blocks.

[0059] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory generate a manufactured article including instruction means, and the instruction means implement the functions specified in one or more of the flows Figure 1 one or more of the flows and / or blocks Figure 1 or means for implementing the functions specified in one or more of the blocks.

[0060] These computer program instructions can also be loaded onto a computer or other programmable data processing device, so that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process, and thus the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one or more of the flows Figure 1 one or more of the flows and / or blocks Figure 1 or means for implementing the functions specified in one or more of the blocks.

[0061] In a typical configuration, a computing device includes one or more processors (CPUs), an input / output interface, a network interface, and memory.

[0062] The memory may include non-permanent memory in the form of computer-readable media, random access memory (RAM), and / or non-volatile memory, such as read-only memory (ROM) or flash memory (flash RAM). The memory is an example of computer-readable media.

[0063] A computer-readable medium includes both permanent and non-permanent, removable and non-removable media and can implement information storage by any method or technology. The information can be computer-readable instructions, data structures, program modules, or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassette tapes, magnetic tape magnetic disk storage or other magnetic storage devices, or any other non-transitory medium that can be used to store information that can be accessed by a computing device. As defined herein, a computer-readable medium does not include transitory computer-readable media, such as modulated data signals and carrier waves.

[0064] It should also be noted that the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, such that a process, method, article or apparatus comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or apparatus. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or apparatus comprising the element.

[0065] The above description is only for the embodiments of the present application and is not intended to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the scope of the claims of the present application.

Claims

1. A voltage monitor, characterized in that, Including: A power management circuit, a sampling and amplifying circuit, a single-chip microcomputer, an adaptive threshold adjustment circuit, and a core board; The sampling and amplifying circuit is connected to the single-chip microcomputer and the adaptive threshold adjustment circuit. The sampling and amplifying circuit includes a first current-limiting resistor and a second current-limiting resistor connected to an input signal; a transformer connected to the first current-limiting resistor and the second current-limiting resistor, where the transformer is a voltage transformer or a current transformer; a sampling resistor connected in parallel with the transformer; an amplifier connected to the transformer; a third current-limiting resistor connected to the amplifier; a series combination of a selection switch of an analog switch and a gating resistor connected in parallel to the inverting input terminal of the amplifier; the selection switch includes a first selection switch and a second selection switch, and the gating resistor includes a first gating resistor, a second gating resistor, a third gating resistor, and a fourth gating resistor; The adaptive threshold adjustment circuit is used to select a voltage range and a current range according to the detected voltage amplitude and current amplitude; The core board is connected to the single-chip microcomputer, used to store monitoring data, and communicate with the power platform through an internal network.

2. The voltage monitor according to claim 1, wherein A reference voltage for lifting an AC signal is connected to the IN+ terminal of the amplifier; The VS+ terminal of the amplifier is connected to the positive power supply, and a first filter capacitor and a second filter capacitor are connected in parallel between the amplifier and the positive power supply, and the first filter capacitor and the second filter capacitor are grounded; A clamping and voltage-limiting circuit is further provided at the output terminal of the sampling and amplifying circuit. The clamping and voltage-limiting circuit includes a clamping and voltage-limiting resistor and a clamping and voltage-limiting diode; the output terminal of the sampling and amplifying circuit is connected to the input terminal of the single-chip microcomputer.

3. A voltage monitor according to claim 1, characterized in that, The voltage monitor further includes: A switch for controlling the on / off of the adaptive voltage detector; A storage battery for powering and debugging the adaptive voltage detector in the absence of an external power supply; A human-computer interaction interface is provided on the single-chip microcomputer, including a display screen and interaction buttons; A communication interface includes a core board modem module, an externally expanded modem module, and an RS485 interface for communicating with other devices; A debugging port is connected to the single-chip microcomputer and the core board for connection and debugging between different devices; the debugging port includes at least one of a USB port, an RS232 port, and a network port.

4. A measurement method of a voltage monitor, applied to the voltage monitor as described in claims 1-3, characterized in that, The method includes: Connect the voltage monitor to the circuit to be detected, and switch the analog switch of the voltage monitor to a preset range; Based on the preset range, collect data from the circuit to be detected to obtain the detected voltage and / or detected current of the circuit to be detected; Based on the detected voltage and / or the detected current, determine the effective voltage and / or effective current of the circuit to be detected.

5. The method according to claim 4, characterized in that, The determining the effective voltage and / or effective current of the circuit to be detected based on the detected voltage and / or the detected current specifically includes: Based on the detected voltage and / or the detected current, adjust the analog switch to a target range; Based on the target range, collect data from the circuit to be detected to obtain a corrected voltage and / or corrected current; Determine the effective voltage and / or effective current of the circuit to be detected based on the corrected voltage and / or the corrected current.

6. The method according to claim 5, characterized in that, The adjusting the analog switch to the target gear based on the detected voltage and / or the detected current specifically includes: Performing a fast Fourier transform on the detected voltage and / or the detected current, and invoking the calibration coefficient corresponding to the preset gear to determine the gear determination voltage and / or gear determination current corresponding to the circuit to be detected; Adjusting the analog switch to the target gear based on the gear determination voltage and / or the gear determination current and a preset gear determination threshold.

7. The method according to claim 4, characterized in that, The method further includes: Before the voltage monitor leaves the factory, detecting a standard power meter through the voltage monitor to obtain a detection sequence; Calibrating the voltage monitor based on the detection sequence.

8. The method according to claim 7, wherein The detecting the standard power meter through the voltage monitor to obtain a detection sequence specifically includes: Switching the analog switch of the voltage monitor to the initial gear; Collecting the standard power meter at a preset sampling frequency to obtain initial detection data; Performing a fast Fourier transform on the initial detection data to obtain the detection sequence.

9. The method according to claim 8, wherein The calibrating the voltage monitor based on the detection sequence specifically includes: Determining the output sequence of the standard power meter; Determining the ratio relationship between the output sequence and the detection sequence; Taking the ratio relationship as the calibration coefficient of the voltage monitor in the initial gear.

10. The method according to claim 9, wherein After taking the ratio as the calibration coefficient of the voltage monitor in the initial gear, the method further includes: Determining the theoretical output sequence of the standard power meter based on the calibration coefficient and the detection sequence; Determining the calibration error corresponding to the calibration coefficient by comparing the theoretical output sequence and the actual output sequence; When the calibration error is lower than a preset error threshold, adjusting the analog switch to other gears until all gears of the voltage monitor are calibrated.

Images