Current measurement method and device

Abstract

The present invention discloses a current measurement method and device. The method includes: passing a current to be measured; first and second current detection units respectively detect the current to be measured in real time to obtain first and second conversion signals; first and second signal conditioning units respectively perform signal conditioning on the first and second conversion signals to obtain first and second conditioned signals; an effective value conversion unit performs true effective value conversion on the first conditioned signal to obtain a signal to be determined; a threshold judgment unit compares the signal to be determined with a preset high and low range switching threshold and outputs a high and low range indication signal and a data selection control signal; a data selection unit selectively outputs the first or second conditioned signal based on the data selection control signal; a range indication unit outputs the high and low range indication signal and synchronizes the high and low range display status in real time; and the amplitude, phase, and frequency of the current to be measured are calculated based on the conditioned signal and the high and low range signals. The present invention can achieve a wide measurement range.

Description

Technical Field

[0001] The present invention relates to the technical field of current measurement, and in particular to a current measurement method and device. Background Art

[0002] With the vigorous development of smart grids, smart transportation, smart homes, and smart factories, the demand for current measurement in electronic devices has increased significantly, and at the same time, increasingly stringent requirements have been placed on high precision and a wide measurement range of current measurement.

[0003] Commonly used sensors for current measurement include shunts, Hall effect current sensors, and fluxgate current sensors. Shunts can experience a sharp temperature increase when overloaded, leading to significant accuracy errors and making it difficult to achieve a balanced measurement range. Hall effect current sensors and fluxgate current sensors rely on a magnetic field concentrator to amplify the magnetic field and improve measurement accuracy. However, due to the magnetic flux saturation problem of the concentrator, the cross-sectional area and volume of the concentrator must be increased to expand the measurement range. This results in bulky, heavy, and expensive sensors.

[0004] Currently, current measurement sensors have the problem of a narrow measurement range. Summary of the Invention

[0005] The present invention provides a current measurement method and device to solve the problem of narrow current measurement range in the prior art.

[0006] According to one aspect of the present invention, a current measurement method is provided, which is applied to a current measurement device, wherein the current measurement device includes: a first current detection unit and a second current detection unit, a first signal conditioning unit and a second signal conditioning unit, an effective value conversion unit, a threshold judgment unit, a data selection unit, and a range indication unit;

[0007] The current measurement method comprises:

[0008] Pass the current to be measured;

[0009] The first current detection unit detects the current to be measured in real time and obtains a first conversion signal; the second current detection unit detects the current to be measured in real time and obtains a second conversion signal;

[0010] The first signal conditioning unit performs signal conditioning on the first conversion signal and obtains a first conditioned signal, wherein the first signal conditioning unit stores a preset high- and low-range switching threshold; the second signal conditioning unit performs signal conditioning on the second conversion signal and obtains a second conditioned signal;

[0011] The effective value conversion unit performs true effective value conversion on the first conditioned signal to obtain a signal to be judged;

[0012] The threshold judgment unit compares the signal to be judged with the preset high and low range switching threshold, and outputs a high and low range indication signal and a data selection control signal;

[0013] The data selection unit selectively outputs the first conditioning signal or the second conditioning signal according to the data selection control signal;

[0014] The range indication unit outputs the high and low range indication signals and synchronizes the high and low range display states in real time;

[0015] The amplitude, phase and frequency of the current to be measured are calculated according to the conditioning signal output by the data selection unit and the high and low range indication signals and high and low range display states output by the range indication unit.

[0016] According to another aspect of the present invention, there is provided a current measuring device comprising: a first current detection unit and a second current detection unit, a first signal conditioning unit and a second signal conditioning unit, an effective value conversion unit, a threshold determination unit, a data selection unit, a range indication unit, and a processing unit;

[0017] The first current detection unit is used to detect the current to be measured in real time and obtain a first conversion signal; the first signal conditioning unit is used to perform signal conditioning on the first conversion signal and obtain a first conditioned signal, wherein the first signal conditioning unit stores a preset high and low range switching threshold; the effective value conversion unit is used to perform true effective value conversion on the first conditioned signal and obtain a signal to be determined;

[0018] The second current detection unit is used to detect the current to be measured in real time and obtain a second conversion signal; the second signal conditioning unit is used to perform signal conditioning on the second conversion signal and obtain a second conditioning signal;

[0019] The threshold judgment unit is used to compare the signal to be judged with the preset high and low range switching threshold, and output a high and low range indication signal and a data selection control signal;

[0020] The data selection unit is configured to selectively output the first conditioned signal or the second conditioned signal according to the data selection control signal;

[0021] The range indication unit is used to synchronize the high and low range display states in real time according to the high and low range indication signals;

[0022] The processing unit is used to calculate the amplitude, phase and frequency of the current to be measured based on the conditioning signal output by the data selection unit and the high and low range indication signals and high and low range display states output by the range indication unit.

[0023] In the present invention, the current measurement device for performing the current measurement method includes two independent current detection units, which can be used to measure currents in different ranges, thereby increasing the measurement range and preventing signal loss. A threshold determination unit dynamically compares the signal to be determined with a preset high- and low-range switching threshold, and switches the first or second conditioned signal in real time, enabling high-precision measurement. This achieves multi-range, high-precision current measurement.

[0024] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present invention, nor is it intended to limit the scope of the present invention. Other features of the present invention will become readily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0026] Figure 1 is a schematic diagram of a current measurement method provided by an embodiment of the present invention;

[0027] Figure 2 is a schematic diagram of a current measuring device provided by an embodiment of the present invention;

[0028] Figure 3 is a schematic diagram of a signal conditioning unit provided by an embodiment of the present invention;

[0029] Figure 4 is a circuit diagram of a signal processing circuit provided by an embodiment of the present invention;

[0030] Figure 5 This is a circuit diagram of another signal processing circuit provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0031] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0032] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0033] Figure 1 is a schematic diagram of a current measurement method provided by an embodiment of the present invention. This embodiment is applicable to current measurement. The method can be performed by a current measurement device, which can be implemented in hardware and / or software and can be configured in any electronic device requiring current measurement.

[0034] Figure 2 1 is a schematic diagram of a current measuring device provided by an embodiment of the present invention. The current measuring device includes a first current detection unit 101 and a second current detection unit 102, a first signal conditioning unit 103 and a second signal conditioning unit 104, an effective value conversion unit 105, a threshold determination unit 106, a data selection unit 107, a range indication unit 108, and a processing unit 109. After a current to be measured is passed through the current measuring device, the current measuring device executes the current measurement method of this embodiment to measure the passed current to be measured.

[0035] like Figure 1 As shown, the current measurement method includes:

[0036] Step S11, passing the current to be measured;

[0037] Step S12: The first current detection unit detects the current to be measured in real time and obtains a first conversion signal; the second current detection unit detects the current to be measured in real time and obtains a second conversion signal;

[0038] Step S13: The first signal conditioning unit performs signal conditioning on the first conversion signal to obtain a first conditioned signal, wherein the first signal conditioning unit stores a preset high and low range switching threshold; the second signal conditioning unit performs signal conditioning on the second conversion signal to obtain a second conditioned signal;

[0039] Step S14: the effective value conversion unit performs true effective value conversion on the first conditioned signal to obtain a signal to be determined;

[0040] Step S15: The threshold determination unit compares the signal to be determined with the preset high and low range switching thresholds, and outputs a high and low range indication signal and a data selection control signal;

[0041] Step S16: The data selection unit selectively outputs the first conditioned signal or the second conditioned signal according to the data selection control signal;

[0042] Step S17: The range indication unit outputs high and low range indication signals and synchronizes the high and low range display states in real time;

[0043] Step S18: Calculate the amplitude, phase and frequency of the current to be measured based on the conditioning signal output by the data selection unit and the high and low range indication signals and high and low range display states output by the range indication unit.

[0044] In this embodiment, the first current detection unit detects the current to be measured in real time and converts the detected signal to obtain a first conversion signal. The second current detection unit detects the current to be measured in real time and converts the detected signal to obtain a second conversion signal. The signal detected by the current detection unit can be an electrical signal related to the current to be measured or a magnetic signal related to the current to be measured, and the conversion signal is obtained by converting the detected signal. The detection process of the current detection unit is not detailed here, and the current detection unit can be either the first current detection unit or the second current detection unit.

[0045] Optionally, the measurement accuracy of the first current detection unit is higher than the measurement accuracy of the second current detection unit, and the measurement range of the first current detection unit is smaller than the measurement range of the second current detection unit. If the measurement accuracy of the first current detection unit is better than the measurement accuracy of the second current detection unit, then the accuracy of the first conversion signal is better than the accuracy of the second conversion signal. If the measurement range of the second current detection unit is wider than the measurement range of the first current detection unit, then the range of the first conversion signal is smaller than the range of the second conversion signal.

[0046] The first current detection unit may be, but is not limited to, a closed-loop current system or a current system based on the fluxgate principle. The second current detection unit may be, but is not limited to, an open-loop current system or a current system based on the array principle. Optionally, the first and second current detection units may share a common circuit board, with components placed in different sections of the circuit board. This ensures that the measurement device does not increase in size due to the expanded measurement range.

[0047] It can be understood that the first current detection unit and the second current detection unit are independent of each other and can perform accurate current detection synchronously. The current detection processes do not interfere with each other, do not restrict each other, and operate independently, presenting double signal insurance to avoid signal loss.

[0048] In this embodiment, a first signal conditioning unit is electrically connected to the first current detection unit. The first signal conditioning unit receives a first conversion signal output by the first current detection unit and performs signal conditioning on the first conversion signal to obtain a first conditioned signal. Correspondingly, a second signal conditioning unit is electrically connected to the second current detection unit. The second signal conditioning unit receives a second conversion signal output by the second current detection unit and performs signal conditioning on the second conversion signal to obtain a second conditioned signal. Preset high and low range switching thresholds are pre-set in the first signal conditioning unit.

[0049] The optional first signal conditioning unit performs signal conditioning on the first conversion signal, including filtering, zero point correction, gain adjustment, nonlinear compensation, temperature compensation, and threshold voltage setting. The optional second signal conditioning unit performs signal conditioning on the second conversion signal, including filtering, zero point correction, gain adjustment, nonlinear compensation, temperature compensation, and threshold voltage setting. This signal conditioning unit can ensure high accuracy and low temperature drift of the current measurement device.

[0050] It can be understood that the first current detection unit performs signal conditioning via the first signal conditioning unit, and the second current detection unit performs signal conditioning via the second signal conditioning unit. These conditioning processes are independent of each other, do not interfere with each other, and do not restrict each other. They operate independently, providing a double guarantee for signals and preventing signal loss. Furthermore, the signal conditioning unit can autonomously and freely condition the converted signal. Those skilled in the art can freely set the high and low ranges of the current measurement device based on actual needs, theoretically without limitation.

[0051] Figure 3 Schematic diagram of a signal conditioning unit provided by an embodiment of the present invention, such as Figure 3 As shown, the signal conditioning unit includes a filter subunit 201, a zero-point correction subunit 202, a gain adjustment subunit 203, a nonlinear compensation subunit 204, a temperature compensation subunit 205, and a threshold voltage setting subunit 206. The filter subunit 201 filters the converted signal; the zero-point correction subunit 202 performs zero-point correction on the filtered converted signal; the gain adjustment subunit 203 performs gain adjustment on the zero-corrected converted signal; the nonlinear compensation subunit 204 performs nonlinear compensation on the gain-adjusted converted signal; the temperature compensation subunit 205 performs temperature compensation on the nonlinearly compensated converted signal; and the threshold voltage setting subunit 206 sets the threshold voltage based on the temperature-compensated converted signal. The signal conditioning unit receives the converted signal, performs multiple signal conditioning operations on the converted signal, and then converts the converted signal into a conditioned signal.

[0052] It should be noted that the signal conditioning operations performed by the signal conditioning unit on the conversion signal include at least filtering, zero point correction, gain adjustment, nonlinear compensation, temperature compensation, and threshold voltage setting, but are not limited thereto and may also include other signal conditioning operations. Furthermore, the order of the signal conditioning operations performed on the conversion signal is not limited thereto and may also be other signal conditioning operation orders. Here, the signal conditioning unit is either the first signal conditioning unit or the second signal conditioning unit.

[0053] Any signal conditioning unit may be a single signal conditioning unit, or a combined signal conditioning unit having multiple identical subunits. That is, in the current measurement device, the first signal conditioning unit is a single signal conditioning unit, and the second signal conditioning unit is a single signal conditioning unit. In other embodiments, the first signal conditioning unit may be a combined signal conditioning unit, with each subunit performing a complete signal conditioning process, and the second signal conditioning unit may be a combined signal conditioning unit, with each subunit performing a complete signal conditioning process.

[0054] In this embodiment, the effective value conversion unit is electrically connected to the first signal conditioning unit. The effective value conversion unit receives the first conditioned signal output by the first signal conditioning unit and performs true effective value conversion on the first conditioned signal to obtain a signal to be determined. The effective value conversion unit can be an RMS-DC true effective value conversion unit; the RMS-DC true effective value conversion unit is a fast-response device and does not affect signal switching speed.

[0055] The threshold determination unit is electrically connected to the effective value conversion unit. The threshold determination unit receives the signal to be determined output by the effective value conversion unit and also obtains a preset high- and low-range switching threshold from the first signal conditioning unit. The threshold determination unit compares the signal to be determined with the preset high- and low-range switching threshold and outputs a data selection control signal and a high- and low-range indication signal based on the comparison result. It should be noted that the high- and low-range indication signals output based on the comparison result should be either a high-range indication signal or a low-range indication signal. The high-range indication signal is typically a high-level signal, and the low-range indication signal is typically a low-level signal.

[0056] It should be noted that the threshold judgment unit is a fast response device, which dynamically compares the signal to be judged with the preset high and low range switching thresholds.

[0057] The data selection unit is electrically connected to the first and second signal conditioning units and the threshold judgment unit, respectively. The data selection unit receives the first conditioning signal output by the first signal conditioning unit and the second conditioning signal output by the second signal conditioning unit. At the same time, the data selection unit receives the data selection control signal output by the threshold judgment unit, and selectively connects and outputs the first conditioning signal or the second conditioning signal in real time according to the data selection control signal. The data selection control signal output by the optional threshold judgment unit can be used as the control signal of the data selection unit. In other embodiments, the high and low range indication signals output by the optional threshold judgment unit can also be used as the control signal of the data selection unit. The data selection unit is a fast response device that can achieve high-speed and seamless switching of ranges, which not only ensures high precision and signal amplitude of current measurement in low ranges, but also effectively widens the measurement range and linear range. The single signal transmission method does not cause loss of measurement signals due to switching speed.

[0058] The optional data selection unit is a switch module capable of receiving external control signals and selecting one of multiple options. This switch module can be an analog switch, multiplexer, or electromagnetic relay. For example, the data selection unit simultaneously receives the data selection control signal and the high and low range indication signals output by the threshold judgment unit. The data selection unit can select either the data selection control signal or the high and low range indication signals as the control signal. Under the control of the control signal, the data selection control unit selectively outputs the first or second conditioned signal. The data selection unit is a high-speed, multiple-select switch module with a control signal. Only one conditioned signal is connected at any given time, eliminating the possibility of measurement signal scrambling or loss.

[0059] The range indicator unit is electrically connected to the threshold determination unit. It receives the high and low range indication signals from the threshold determination unit and synchronizes the high and low range display status in real time based on the high and low range indication signals. The optional range indicator unit can display the range status via a light-emitting diode or display, while simultaneously outputting a high or low level range indication signal. This redundant design improves functional safety and significantly reduces data transmission errors.

[0060] The processing unit is electrically connected to the data selection unit and the range indication unit, receiving the first or second conditioned signal output by the data selection unit, as well as the high and low range indication signals and their display status output by the range indication unit. Based on the conditioned signal, high and low range indication signals, and their display status, the processing unit calculates the amplitude, phase, and frequency characteristics of the current to be measured, thereby achieving measurement of the current to be measured. The optional processing unit can be a digital circuit or digital display with A / D conversion, arithmetic processing, and communication functions, facilitating back-end signal sampling and rapid identification.

[0061] The output signal of the optional current measurement device includes the output signal of the data selection unit and the high and low range indication signals and high and low range display states of the range indication unit. It can be understood that the output signal includes the signal output by the data selection unit and the indication signal output by the range indication unit. Therefore, the same signal output by the data selection unit can represent different magnitudes of the current to be measured under different signal states of the range indication unit. Obviously, such a setting can effectively increase the amplitude of the measurement signal of the current signal to be measured in the low range, thereby reducing the accuracy requirements and cost of the back-end sampling equipment and improving the convenience and reliability of sampling.

[0062] In the present invention, the current measurement device for performing the current measurement method includes two independent current detection units, which can be used to measure currents in different ranges, thereby increasing the measurement range and preventing signal loss. A threshold determination unit dynamically compares the signal to be determined with a preset high- and low-range switching threshold, and switches the first or second conditioned signal in real time, enabling high-precision measurement. This achieves multi-range, high-precision current measurement.

[0063] The optional current measurement method further includes: the data selection unit selectively outputting the first conditioned signal or the second conditioned signal based on the high-range and low-range indication signals. The data selection unit can simultaneously receive the data selection control signal and the high-range and low-range indication signals output by the threshold determination unit. The data selection unit can select to use the data selection control signal as a control signal or the high-range and low-range indication signals as a control signal. Under the control of the control signal, the data selection control unit selectively outputs the first conditioned signal or the second conditioned signal.

[0064] The optional threshold judgment unit compares the signal to be judged with the preset high-low range switching threshold, and outputs a high-low range indication signal and a data selection control signal, including: the threshold judgment unit outputs a low-level control signal when detecting that the signal to be judged is less than the preset high-low range switching threshold; or, the threshold judgment unit outputs a high-level control signal when detecting that the signal to be judged is greater than or equal to the preset high-low range switching threshold.

[0065] The optional data selection unit selectively outputs the first conditioned signal or the second conditioned signal according to the data selection control signal, including: the data selection unit outputs the first conditioned signal after receiving the low-level control signal, and the range indication unit outputs the low-level range indication signal and displays the low-range state after receiving the low-level control signal; or, the data selection unit outputs the second conditioned signal after receiving the high-level control signal, and the range indication unit outputs the high-level range indication signal and displays the high-range state after receiving the high-level control signal.

[0066] In this embodiment, when the threshold determination unit detects that the signal to be determined is less than a preset high-low range switching threshold, the threshold determination unit outputs a low-level control signal, which serves as a low-range indication signal. The data selection unit receives the low-level control signal and, under the control of the low-level control signal, outputs a first conditioned signal. Simultaneously, the range indication unit receives the low-level control signal and, based on the low-level control signal, outputs a low-range indication signal, which is displayed synchronously in real time as a low-range state.

[0067] Conversely, when the threshold determination unit detects that the signal to be determined is greater than or equal to the preset high-range / low-range switching threshold, it outputs a high-level control signal, which serves as the high-range indication signal. The data selection unit receives the high-level control signal and, under its control, outputs a second conditioned signal. Simultaneously, the range indication unit receives the high-level control signal and, based on the high-level control signal, outputs a high-range indication signal, displaying the high-range status in real time.

[0068] As described above, the signal conditioning unit, effective value conversion unit, threshold judgment unit, data selection unit and range indication unit constitute the signal processing circuit of the current measuring device, which can better cooperate with and give full play to the advantage of the current measurement method in broadening the current measurement range.

[0069] Based on the same inventive concept, an embodiment of the present invention further provides a current measuring device, which can execute the current measuring method described in any of the above embodiments.

[0070] refer to Figure 2As shown, the current measuring device includes: a first current detection unit 101 and a second current detection unit 102, a first signal conditioning unit 103 and a second signal conditioning unit 104, an effective value conversion unit 105, a threshold judgment unit 106, a data selection unit 107, a range indication unit 108 and a processing unit 109. The first current detection unit 101 is used to detect the current to be measured in real time and obtain a first conversion signal; the first signal conditioning unit 103 is used to perform signal conditioning on the first conversion signal and obtain a first conditioned signal, wherein the first signal conditioning unit 103 stores a preset high and low range switching threshold; the effective value conversion unit 105 is used to perform true effective value conversion on the first conditioned signal and obtain a signal to be judged; the second current detection unit 102 is used to detect the current to be measured in real time and obtain a second conversion signal; the second signal conditioning unit 104 is used to perform signal conditioning on the second conversion signal and obtain a second conditioning signal; the threshold judgment unit 106 is used to compare the signal to be judged with the preset high and low range switching threshold, and output the high and low range indication signal and the data selection control signal; the data selection unit 107 is used to selectively output the first conditioning signal or the second conditioning signal according to the data selection control signal; the range indication unit 108 is used to synchronize the high and low range display status in real time according to the high and low range indication signal; the processing unit 109 is used to calculate the amplitude, phase and frequency of the current to be measured based on the conditioning signal output by the data selection unit and the high and low range indication signal and the high and low range display status output by the range indication unit.

[0071] As described above, the signal conditioning unit, effective value conversion unit, threshold judgment unit, data selection unit and range indication unit constitute the signal processing circuit of the current measuring device, which can better cooperate with and give full play to the advantage of the current measurement method in broadening the current measurement range.

[0072] Figure 4 FIG is a circuit diagram of a signal processing circuit provided by an embodiment of the present invention. Figure 4 As shown, the optional first signal conditioning unit includes a conditioning chip N1 and its peripheral capacitor element C7, and the second signal conditioning unit includes a conditioning chip N2 and its peripheral capacitor element C8. Both N1 and N2 have filtering, zero point correction, gain adjustment, nonlinear compensation, temperature compensation and threshold voltage setting functions. The RMS-DC true effective value conversion unit includes a chip N3 with an RMS-DC true effective value conversion function and its peripheral capacitor elements C5 and C6. The threshold judgment unit includes a voltage comparator N4. The data selection unit includes a high-speed dual-channel analog switch SW with an enable pin. The range indication unit has range status display and range signal indication functions. The structure that performs the range status display function includes light-emitting diodes LED1 & LED2 and current limiting resistors R1 & R2.

[0073] Figure 4In the figure, signals V1+ and V1- represent the differential form of the first conversion signal V1 output by the first current detection unit, and signals V2+ and V2- represent the differential form of the second conversion signal V2 output by the second current detection unit. Vo1 represents the first conditioned signal output by the first signal conditioning unit, and Vo2 represents the second conditioned signal output by the second signal conditioning unit. V+, V-, and GND are the supply voltages; VF represents the range indication signal sent by the range indication unit, and VF is classified as high or low level; Vout is the output signal of the signal processing circuit. Vout can also be used as an output signal terminal to connect to a subsequent processing unit, such as an analog circuit, a digital circuit with A / D conversion function, a digital circuit with arithmetic processing function, a digital circuit with communication function, or a digital display screen.

[0074] The first converted signals V1+ and V1- are conditioned by the conditioning chip N1 and output as the first conditioned signal Vo1. The first conditioned signal Vo1 is converted to a true RMS-DC value by the RMS-DC conversion chip N3 and output as a DC signal to be determined (VD). The DC signal to be determined (VD) is connected to the positive input terminal (pin 3) of the voltage comparator N4. The negative input terminal (pin 2) of the voltage comparator N4 is connected to pin 4 of the conditioning chip N1. The negative input terminal of the voltage comparator N4 is used to receive the preset high- and low-range switching threshold voltage VREF set by the conditioning chip N1.

[0075] The second converted signals V2+ and V2- are conditioned by the conditioning chip N2 and output as the second conditioned signal Vo2. The second conditioned signal Vo2 is transmitted to the pin S2 of the analog switch SW.

[0076] When VD < VREF, pin 1 of voltage comparator N4 outputs a low level, and the corresponding range indicator signal VF is also low, causing LED 1 (indicating the low range) to turn on and LED 2 (indicating the high range) to turn off. Simultaneously, control pin A1 of analog switch SW is low, connecting pins D and S1, and outputting the first conditioned signal Vo1.

[0077] When VD > VREF, pin 1 of voltage comparator N4 outputs a high level, and the corresponding range-indicating signal VF is also high, turning on LED 2 (indicating the high range) and off LED 1 (indicating the low range). Simultaneously, control pin A1 of analog switch SW is high, connecting pins D and S2, and outputting the second conditioned signal Vo2.

[0078] Figure 4 The states of the signal processing circuit shown are detailed in Table 1 below.

[0079]

[0080] It is worth mentioning that the conditioning signals Vo1 and Vo2 can be set to the same dynamic range or different dynamic ranges according to actual needs. The dynamic ranges of the two signals do not interfere with or restrict each other and operate independently, which can provide a double signal insurance effect and effectively avoid signal loss. At the same time, the analog switch SW with high-speed switching function can only connect to a single conditioning signal Vo1 or Vo2 at the same time and does not participate in signal control, so it will not affect the signal transmission rate or cause data disorder or loss.

[0081] It's important to note that the signal processing circuit's output signal consists of the data selection unit's output signal and the range indicator unit's range indication signal. This means that the same data selection unit output signal, under different range indication signal states, represents different measured currents. Therefore, the subsequent processing unit must combine the data selection unit output signal and the range indicator unit output signal to accurately calculate information such as the measured current amplitude, phase, and frequency. Furthermore, the provision of light-emitting diodes (LED1) and LED2 allows for convenient, intuitive, and preliminary determination of the measured current range, greatly enhancing the applicability of the current test device.

[0082] In order to further improve the measurement accuracy of current in different intervals, more ranges can be divided according to actual needs. Figure 5 This is a circuit diagram of another signal processing circuit provided by an embodiment of the present invention. Figure 5 The working mechanism of the signal processing circuit provided is similar to Figure 4 Highly similar, the similarities are not repeated here. The difference between the two is that, Figure 5 The first signal conditioning unit is equipped with two signal conditioning sub-units with the same functions, and the second signal conditioning unit is equipped with two signal conditioning sub-units with the same functions. At the same time, the RMS-DC true effective value conversion unit is increased to two groups, the voltage comparator is divided into four paths, the range status indicator light is increased to five, and the analog switch is replaced with 8 channels.

[0083] The RMS-DC true effective value conversion chips N3-1 and N3-2 respectively collect and convert the low-range and high-range high-bit signals.

[0084] Voltage comparator N4A compares the signal to be determined VD1 with the preset range switching threshold voltage VREF1 in real time and outputs a range indication signal VF1. Voltage comparator N4B compares the signal to be determined VD1 with the preset range switching threshold voltage VREF2 in real time and outputs a range indication signal VF2. Voltage comparator N4C compares the signal to be determined VD2 with the preset range switching threshold voltage VREF3 in real time and outputs a range indication signal VF3. Voltage comparator N4D compares the signal to be determined VD2 with the preset range switching threshold voltage VREF4 in real time and outputs a range indication signal VF4.

[0085] The levels of range-indicator signals VF1 through VF4 control the states of LEDs 1 through 5, turning on the corresponding channels through analog switches SW. The output of voltage comparator N4D controls the state of LED 5, indicating whether the maximum current measurement range has been exceeded. For more detailed information on the range states and their meanings, please refer to Table 2 below.

[0086]

[0087]

[0088] Obviously, this setup can effectively increase the amplitude of the current to be measured within the low-range range, thereby reducing the sampling accuracy requirements and cost of the current measurement device, and improving the convenience and reliability of information collection. Furthermore, the first signal conditioning unit and the second signal conditioning unit can reasonably set up multiple signal conditioning sub-units according to actual needs, while dividing more ranges, further improving the current measurement accuracy in different intervals.

[0089] In summary, the present invention integrates two different current detection units and uses a high-speed data selection unit to realize data transmission and automatic and rapid switching of high and low ranges, effectively solving the problems of large size, narrow measurement range and high cost in traditional isolated current testing methods. The current measurement device provided by the present invention has the advantages of saving space, high accuracy and wide measurement range.

[0090] It should be understood that the various forms of the processes shown above can be used to reorder, add, or delete steps. For example, the steps described in the present invention can be performed in parallel, sequentially, or in a different order, as long as the desired results of the technical solution of the present invention can be achieved. This is not limited herein.

[0091] The above specific embodiments do not limit the scope of protection of the present invention. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions may be made based on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are intended to be included within the scope of protection of the present invention.

Claims

1. A current measurement method, characterized in that: Applicable to a current measuring device, the current measuring device comprises: a first current detection unit and a second current detection unit, a first signal conditioning unit and a second signal conditioning unit, an effective value conversion unit, a threshold judgment unit, a data selection unit and a range indication unit; The current measurement method comprises: Pass the current to be measured; The first current detection unit detects the current to be measured in real time and obtains a first conversion signal; the second current detection unit detects the current to be measured in real time and obtains a second conversion signal; the first current detection unit is a closed-loop current system or a current system based on the fluxgate principle, and the second current detection unit is an open-loop current system or a current system based on the array principle; wherein the signal detected by the current detection unit is an electrical signal related to the current to be measured, or a magnetic signal related to the current to be measured, and the conversion signal is obtained by converting the detected signal; The first signal conditioning unit performs signal conditioning on the first conversion signal and obtains a first conditioned signal, wherein the first signal conditioning unit stores a preset high- and low-range switching threshold; the second signal conditioning unit performs signal conditioning on the second conversion signal and obtains a second conditioned signal; The effective value conversion unit performs true effective value conversion on the first conditioned signal to obtain a signal to be judged; The threshold judgment unit compares the signal to be judged with the preset high and low range switching threshold, and outputs a high and low range indication signal and a data selection control signal; The data selection unit selectively outputs the first conditioning signal or the second conditioning signal according to the data selection control signal; The range indication unit outputs the high and low range indication signals and synchronizes the high and low range display states in real time; The amplitude, phase and frequency of the current to be measured are calculated according to the conditioning signal output by the data selection unit and the high and low range indication signals and high and low range display states output by the range indication unit.

2. The current measurement method according to claim 1, characterized in that: The measurement accuracy of the first current detection unit is higher than that of the second current detection unit, and the measurement range of the first current detection unit is smaller than that of the second current detection unit.

3. The current measurement method according to claim 1, wherein: The first signal conditioning unit performing signal conditioning on the first conversion signal includes: The first signal conditioning unit performs filtering, zero point correction, gain adjustment, nonlinear compensation, temperature compensation and threshold voltage setting on the first conversion signal; The second signal conditioning unit performing signal conditioning on the second conversion signal includes: The second signal conditioning unit performs filtering, zero point correction, gain adjustment, nonlinear compensation, temperature compensation and threshold voltage setting on the second conversion signal.

4. The current measurement method according to claim 1, characterized in that: Also includes: The data selection unit further selectively outputs the first conditioned signal or the second conditioned signal according to the high and low range indication signals.

5. The current measurement method according to claim 1, characterized in that: The threshold judgment unit compares the signal to be judged with the preset high and low range switching threshold, and outputs a high and low range indication signal and a data selection control signal, including: The threshold judgment unit outputs a low-level control signal when detecting that the signal to be judged is less than the preset high-low range switching threshold; or, The threshold judgment unit outputs a high-level control signal when detecting that the signal to be judged is greater than or equal to the preset high-range and low-range switching threshold.

6. The current measurement method according to claim 5, characterized in that: The data selection unit selectively outputting the first conditioned signal or the second conditioned signal according to the data selection control signal includes: The data selection unit outputs the first conditioning signal after receiving the low-level control signal, and the range indication unit outputs a range low-level indication signal and displays a low-range state after receiving the low-level control signal; or The data selection unit outputs the second conditioning signal after receiving the high-level control signal, and the range indication unit outputs a range high-level indication signal and displays a high-range state after receiving the high-level control signal.

7. The current measurement method according to claim 1, characterized in that: The output signal of the current measuring device includes the output signal of the data selection unit and the high and low range indication signals and high and low range display states of the range indication unit.

8. A current measuring device, characterized in that: include: A first current detection unit and a second current detection unit, a first signal conditioning unit and a second signal conditioning unit, an effective value conversion unit, a threshold judgment unit, a data selection unit, a range indication unit and a processing unit; The first current detection unit is used to detect the current to be measured in real time and obtain a first conversion signal; the first signal conditioning unit is used to perform signal conditioning on the first conversion signal and obtain a first conditioned signal, wherein the first signal conditioning unit stores a preset high and low range switching threshold; the effective value conversion unit is used to perform true effective value conversion on the first conditioned signal and obtain a signal to be determined; The second current detection unit is used to detect the current to be measured in real time and obtain a second conversion signal; the second signal conditioning unit is used to perform signal conditioning on the second conversion signal and obtain a second conditioning signal; The first current detection unit is a closed-loop current system or a current system based on the fluxgate principle, and the second current detection unit is an open-loop current system or a current system based on the array principle; wherein the signal detected by the current detection unit is an electrical signal related to the current to be measured, or a magnetic signal related to the current to be measured, and the detected signal is converted to obtain a conversion signal; The threshold judgment unit is used to compare the signal to be judged with the preset high and low range switching threshold, and output a high and low range indication signal and a data selection control signal; The data selection unit is configured to selectively output the first conditioned signal or the second conditioned signal according to the data selection control signal; The range indication unit is used to synchronize the high and low range display states in real time according to the high and low range indication signals; The processing unit is used to calculate the amplitude, phase and frequency of the current to be measured based on the conditioning signal output by the data selection unit and the high and low range indication signals and high and low range display states output by the range indication unit.

9. The current measuring device according to claim 8, characterized in that Any signal conditioning unit is a single signal conditioning unit, or any signal conditioning unit is a combined signal conditioning unit having multiple identical sub-units.

10. The current measuring device according to claim 8, characterized in that The data selection unit is a switch module with a function of receiving multiple selections from external control. The switch module is an analog switch, a multiplexer, or an electromagnetic relay.

Images