Current detection method, device, equipment and program product
By incorporating a current sensing device, voltage divider circuit, and control circuit in the current detection equipment, the problems of complex electrical wiring framework and high cost are solved, thereby simplifying current detection and improving its accuracy.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CONTEMPORARY AMPEREX FUTURE ENERGY RES INST (SHANGHAI) LTD
- Filing Date
- 2024-11-14
- Publication Date
- 2026-05-15
AI Technical Summary
In existing technologies, large-amplitude current detection requires complex electrical wiring frameworks, resulting in higher costs.
A current detection device is used, including a current sensing device, a voltage divider circuit, and a control circuit. The induced current is converted into different voltage dividers through the voltage divider circuit. A single current sensing device is used to adapt to a large current range. The current value is determined by combining the voltage amplification circuit and the control circuit.
It simplifies the electrical wiring framework, reduces costs, and improves the accuracy and reliability of current detection.
Smart Images
Figure CN122043036A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of testing, and in particular to current detection methods, apparatus, equipment and procedures. Background Technology
[0002] Flexible DC transmission technology combined with on-site energy storage via energy storage valves can effectively integrate renewable energy sources such as wind and solar power into the power grid, improving energy utilization efficiency. Through energy storage and release via energy storage valves, the power quality of the grid can be improved, enhancing grid stability and transient response capabilities. Energy storage valves typically consist of several sub-modules connected in series to form a higher voltage, which is then connected to the DC bus. The neutral point of the energy storage valve is grounded via a grounding resistor. By collecting the grounding current at the neutral point, grounding faults in other sub-modules can be detected.
[0003] Because the grounding current varies considerably, two or more current sensing devices with different ranges are typically selected for detection. A large-range current sensing device detects high currents, while a small-range current sensing device detects low currents. The need for more than one current sensing device complicates the electrical wiring structure and increases costs. Summary of the Invention
[0004] In view of this, embodiments of this application provide a current detection method, apparatus, device, and program product to solve the problem that the electrical wiring framework is relatively complex and costly when performing large-amplitude current detection in the prior art.
[0005] A first aspect of this application provides a current detection device, comprising: a current sensing device, a voltage divider circuit, and a control circuit; the current sensing device is used to acquire the induced current of a circuit to be detected; the voltage divider circuit is used to determine, based on the induced current, at least a first voltage divider voltage and a second voltage divider voltage, wherein the first voltage divider voltage is greater than the second voltage divider voltage; and the control circuit is used to determine a first current value of the circuit to be detected based on the first voltage divider voltage and the second voltage divider voltage.
[0006] This current detection device acquires induced current through a current sensing device, and presents the induced current as a first voltage divider and a second voltage divider through a voltage divider circuit. Based on the determined first and second voltage dividers, a first current value of the circuit to be detected is determined. Since the magnitudes of the voltage dividers presented by the induced current are different, only a single current sensing device is needed to meet the current detection requirements of a large current range. Compared to methods that use two or more current sensors for detection, the embodiments of this application require fewer current sensing devices, which helps to reduce costs and simplify the electrical wiring framework.
[0007] In conjunction with the first aspect, in a first possible implementation of the first aspect, the current detection device further includes a voltage amplification circuit, which includes a first voltage amplification circuit and a second voltage amplification circuit, wherein: the first voltage amplification circuit is used to amplify the first voltage divider to obtain a first amplified voltage; the second voltage amplification circuit is used to amplify the second voltage divider to obtain a second amplified voltage; and the control circuit is used to determine a first current value of the circuit to be detected based on the first amplified voltage and the second amplified voltage.
[0008] In order to obtain the detection result of the first current value more accurately, the embodiments of this application further set up a voltage amplification circuit. The first voltage divider voltage and the second voltage divider voltage presented by the voltage divider circuit are amplified by the first voltage amplification circuit and the second voltage amplification circuit respectively to obtain the first amplified voltage and the second amplified voltage. By setting the amplification factor, the first amplified voltage and the second amplified voltage can be effectively adapted to the detection range of the control circuit, thereby improving the accuracy of the detected voltage, so as to determine the first current value based on the more accurate first amplified voltage and the second amplified voltage.
[0009] In conjunction with the first possible implementation of the first aspect, in the second possible implementation of the first aspect, the first voltage amplifier circuit includes a first operational amplifier, the first voltage divider voltage serves as the common-mode voltage of the first operational amplifier, and the first operational amplifier outputs a first amplified voltage; the second voltage amplifier circuit includes a second operational amplifier, the second voltage divider voltage serves as the common-mode voltage of the second operational amplifier, and the second operational amplifier outputs a second amplified voltage.
[0010] The first voltage divider is used as the common-mode voltage and amplified by the first operational amplifier. The gain setting resistor in the first operational amplifier ensures an ideal amplification of the first voltage divider without the amplifier saturating. Similarly, the second voltage divider is amplified by the second operational amplifier to obtain the ideal amplified voltage. The amplification factor of the first operational amplifier can be the same as or different from that of the second operational amplifier.
[0011] In conjunction with the second possible implementation of the first aspect, in the third possible implementation of the first aspect, the voltage divider circuit includes a first voltage divider resistor and a second voltage divider resistor, the first voltage divider resistor and the second voltage divider resistor are connected in series, the induced current of the circuit under test generates a first voltage divider voltage when it passes through the first voltage divider resistor, and the induced current of the circuit under test generates a second voltage divider voltage when it passes through the second voltage divider resistor; the control circuit is used to determine the second current value induced by the circuit under test based on the resistance value of the first voltage divider resistor, the resistance value of the second voltage divider resistor, the amplification factor of the first operational amplifier, the amplification factor of the second operational amplifier, the first amplification voltage, and the second amplification voltage, and to determine the first current value of the circuit under test based on the second current value induced by the circuit under test.
[0012] By connecting the first and second voltage-dividing resistors in series, the induced current passing through them generates a first voltage divider and a second voltage divider. When the control circuit determines the first current value based on the amplified voltage, if the first current value is determined based on the first amplified voltage, the first voltage divider can be determined based on the first operational amplifier and the first amplified voltage. The magnitude of the induced current can be determined based on the resistance value of the first voltage-dividing resistor and the first voltage divider. Then, the first current value can be effectively determined using the induction coefficient of the current sensing device. Alternatively, if the first current value is determined based on the second amplified voltage, the first voltage divider can be determined based on the first operational amplifier and the first amplified voltage. The magnitude of the induced current can be determined based on the resistance value of the first voltage-dividing resistor and the first voltage divider. Then, the first current value can be effectively determined using the induction coefficient of the current sensing device.
[0013] In conjunction with the third possible implementation of the first aspect, in the fourth possible implementation of the first aspect, the current sensing device is a zero flux current sensor, and the control circuit is used to determine the first current value of the circuit to be tested based on the second current value sensed by the circuit to be tested, combined with the number of turns of the windings on the primary and secondary sides of the zero flux current sensor.
[0014] A zero-flux current sensor is a current sensing device based on the principles of magnetic modulation and magnetic balance. It utilizes the mechanism of alternating saturation of a high-permeability iron core under saturation excitation of an alternating magnetic field to rapidly modulate the primary current of the circuit under test to the secondary coil through the ampere-turn principle. This causes the magnetic field generated by the induced current output by the secondary coil to cancel out the magnetic field generated by the primary current. Therefore, the induced current of the secondary coil, combined with the number of turns of the primary and secondary coils, can accurately reflect the magnitude of the current in the circuit under test.
[0015] In conjunction with the third possible implementation of the first aspect, in the fifth possible implementation of the first aspect, the control circuit is used to estimate the third current value induced by the circuit under test based on the resistance value of the first voltage divider resistor, the amplification factor of the first operational amplifier, and the first amplification voltage; to estimate the fourth current value induced by the circuit under test based on the resistance value of the second voltage divider resistor, the amplification factor of the second operational amplifier, and the second amplification voltage; and to determine the second current value induced by the circuit under test based on the third current value, the fourth current value, and a preset current threshold.
[0016] When determining the second current value of the induced current, the first voltage divider value can be determined based on the first amplified voltage and the amplification factor of the first operational amplifier. The third current value induced by the circuit under test can then be estimated based on the first voltage divider value and the first voltage divider resistor. The second voltage divider value can be determined based on the second amplified voltage and the amplification factor of the second operational amplifier. The fourth current value induced by the circuit under test can then be estimated based on the second voltage divider value and the second voltage divider resistor. The magnitude of the current in the circuit under test can be determined based on the magnitude of the third or fourth current value. If the current is large, such as exceeding the current setpoint, the first current value can be determined using the smaller second voltage divider value. If the current in the circuit under test is small, the first current value can be determined using the larger first voltage divider value. This ensures that the voltage value used for calculation is within a suitable range, allowing for accurate and reliable acquisition of the amplified voltage.
[0017] In conjunction with the fifth possible implementation of the first aspect, in the sixth possible implementation of the first aspect, the control circuit is configured to: determine a second current value induced by the circuit under test based on the fourth current value when the third current value or the fourth current value is less than a preset first current threshold; determine a second current value induced by the circuit under test based on the third current value when the third current value or the fourth current value is greater than a preset second current threshold; and continue to determine a second current value induced by the circuit under test based on the previously selected third current value or fourth current value when the third current value or the fourth current value is greater than or equal to the first current threshold and less than or equal to the second current threshold; wherein the first current threshold is less than the second current threshold.
[0018] By setting a first current threshold and a second current threshold, when the first current value of the circuit under test is determined to be greater than the second current threshold based on a third or fourth current value, the third current value can be determined as the second current value induced by the circuit under test. When the first current value of the circuit under test is determined to be less than the second current threshold based on a third or fourth current value, the fourth current value can be determined as the second current value induced by the circuit under test. Once the type of current value used to calculate the second current value (third or fourth current value) has been determined, if the type of current value used to calculate the second current value is the third current value, then the system will only switch to using the fourth current value to determine the second current value if the third current value is less than the first current threshold. Similarly, if the type of current value used to calculate the second current value has been determined to be the fourth current value, then the system will only switch to using the third current value to determine the second current value if the fourth current value is greater than the second current threshold. By setting two current thresholds for switching control, the problem of frequent switching caused by current jitter can be effectively reduced.
[0019] Secondly, embodiments of this application propose a current detection method, which includes: estimating a third current value induced in a circuit under test based on a first voltage divider detected by a current detection device according to any one of the first aspects; estimating a fourth current value induced in the circuit under test based on a second voltage divider detected by the current detection device; selecting either the third current value or the fourth current value to determine a second current value induced in the circuit under test based on the magnitude of the third current value or the fourth current value; and determining a first current value of the circuit under test based on the second current value and in conjunction with the induction coefficient of the current sensing device.
[0020] The current detection method in this application embodiment can calculate the induced third current value and fourth current value based on the first voltage divider voltage and the second voltage divider voltage determined by the current detection device. According to the magnitude of the induced current, a more suitable current value (third current value or fourth current value) can be selected to calculate the first current value. That is, the first current value is determined by the induced current and the induction coefficient. Only a single current sensing device is needed to effectively adapt to a large range of current detection, which is beneficial to reduce costs and simplify the electrical wiring framework.
[0021] In conjunction with the second aspect, in a first possible implementation of the second aspect, determining the second current value induced by the circuit under test based on the magnitude of the third current value or the fourth current value includes: determining the second current value induced by the circuit under test based on the fourth current value when the third current value or the fourth current value is less than a preset first current threshold; determining the second current value induced by the circuit under test based on the third current value when the third current value or the fourth current value is greater than the preset second current threshold; and continuing to determine the second current value induced by the circuit under test according to the previously selected third current value or the fourth current value when the third current value or the fourth current value is greater than or equal to the first current threshold and less than or equal to the second current threshold; wherein the first current threshold is less than the second current threshold.
[0022] By setting a first current threshold and a second current threshold, when the first current value of the circuit under test is determined to be greater than the second current threshold based on a third or fourth current value, the third current value can be determined as the second current value induced by the circuit under test. When the first current value of the circuit under test is determined to be less than the second current threshold based on a third or fourth current value, the fourth current value can be determined as the second current value induced by the circuit under test. Once the type of current value used to calculate the second current value (third or fourth current value) has been determined, if the type of current value used to calculate the second current value is the third current value, then the system will only switch to using the fourth current value to determine the second current value if the third current value is less than the first current threshold. Similarly, if the type of current value used to calculate the second current value has been determined to be the fourth current value, then the system will only switch to using the third current value to determine the second current value if the fourth current value is greater than the second current threshold. By setting two current thresholds for switching control, the problem of frequent switching caused by current jitter can be effectively reduced.
[0023] In conjunction with the second aspect, in a second possible implementation of the second aspect, the current sensing device is a zero-flux current sensor; determining the first current value of the circuit to be tested based on the second current value and the sensing coefficient of the current sensing device includes: determining the first current value of the circuit to be tested based on the number of turns of the primary and secondary windings of the zero-flux current sensor and the second current value.
[0024] A zero-flux current sensor is a current sensing device based on the principles of magnetic modulation and magnetic balance. It utilizes the mechanism of alternating saturation of a high-permeability iron core under saturation excitation of an alternating magnetic field to rapidly modulate the primary current of the circuit under test to the secondary coil through the ampere-turn principle. This causes the magnetic field generated by the induced current output by the secondary coil to cancel out the magnetic field generated by the primary current. Therefore, the induced current of the secondary coil, combined with the number of turns of the primary and secondary coils, can accurately reflect the magnitude of the current in the circuit under test.
[0025] In a third possible implementation of the second aspect, in conjunction with any of the second aspects to the second possible implementations of the second aspect, before estimating the third current value induced by the circuit under test based on the first voltage divider voltage detected by the current detection device, and before estimating the fourth current value induced by the circuit under test based on the second voltage divider voltage of the current detection device, the method further includes: performing current detection based on a predetermined current set for the circuit under test to obtain a first current value corresponding to the predetermined current; determining a calibration coefficient based on the predetermined current and the first current value; after determining the first current value of the circuit under test based on the second current value and the sensing coefficient of the current sensing device, the method further includes: calibrating the first current value based on the calibration coefficient to obtain a calibration current value.
[0026] By setting the current flowing through the circuit under test as a predetermined current, the detected first current value is compared and analyzed with the predetermined current to determine the calibration coefficient used to calibrate the first current value. After determining the calibration coefficient, the first current value can be calibrated to obtain the calibration current value, thereby making the test results more accurate.
[0027] A third aspect of this application provides a current detection device, the device comprising: a current value detection unit, configured to estimate a third current value induced in a circuit under test based on a first voltage divider detected by the current detection device according to any one of the first aspects, and to estimate a fourth current value induced in the circuit under test based on a second voltage divider detected by the current detection device; a current value selection unit, configured to select the third current value or the fourth current value to determine a second current value induced in the circuit under test based on the magnitude of the third current value or the fourth current value; and a first current value determination unit, configured to determine a first current value of the circuit under test based on the second current value and in conjunction with the induction coefficient of the current sensing device.
[0028] A fourth aspect of this application provides a current sensing device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the current sensing device performs the method as described in any of the first aspects.
[0029] A fifth aspect of this application provides a computer program product that, when run on a computer, causes the computer to execute the methods described in the first aspect or its various implementations.
[0030] A sixth aspect of this application provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the method as described in any of the first aspects.
[0031] A seventh aspect of this application provides a chip for implementing the methods in the various implementations of the first aspect described above. Specifically, the chip includes a processor for calling and running a computer program from a memory, causing a device equipped with the chip to perform the methods as described in the first aspect or its various implementations.
[0032] It is understood that the beneficial effects of the second to seventh aspects mentioned above can be found in the relevant description of the first aspect mentioned above, and will not be repeated here. Attached Figure Description
[0033] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0034] Figure 1 This is a schematic diagram of a current detection device with multiple current sensors provided in an embodiment of this application;
[0035] Figure 2 This is a schematic diagram of a current detection scenario provided in an embodiment of this application;
[0036] Figure 3 This is a schematic diagram of a current detection device provided in an embodiment of this application;
[0037] Figure 4 This is a schematic diagram of a current detection device provided in an embodiment of this application;
[0038] Figure 5 This is a schematic diagram of a current detection process provided in an embodiment of this application;
[0039] Figure 6 This is a schematic diagram illustrating the implementation process of a current switching method provided in an embodiment of this application;
[0040] Figure 7 This is a schematic diagram of a current detection device provided in an embodiment of this application;
[0041] Figure 8 This is a schematic diagram of a current detection device provided in an embodiment of this application. Detailed Implementation
[0042] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.
[0043] To illustrate the technical solution described in this application, specific embodiments are provided below.
[0044] Flexible DC transmission technology combined with an on-site energy storage system using an energy storage valve can efficiently integrate renewable energy sources such as wind and solar power into the power grid, improving energy utilization efficiency. This system stores and releases energy through the energy storage valve, helping to improve the power quality of the grid, enhance grid stability, and improve its response to transient events. The energy storage valve consists of multiple sub-modules connected in series to form a higher voltage and is connected to the DC bus. The neutral point of the energy storage valve can be grounded through a grounding resistor to improve safety.
[0045] To monitor grounding faults in the energy storage valve submodule, the system collects the grounding current at the neutral point. Because the grounding current varies considerably, two or more current sensors with different ranges are typically used for detection. A high-current sensor detects larger currents, while a low-current sensor detects smaller currents. While this use of multiple sensors improves detection accuracy, it also increases the complexity of the electrical wiring framework, thereby increasing costs.
[0046] for example Figure 1 As shown, two or more current sensors 1 and 2 with different ranges are selected to detect the current. By measuring the output signals of the sensors with different ranges, the smaller range current sensor 1 is used when the current to be detected is small, and the larger range current sensor 2 is used when the current to be detected is large. In this case, the smaller range current sensor 1 may be operating in a saturated state. A ground loop current problem may occur between the two current sensors (e.g., Figure 1 (As shown by the dashed line in the image).
[0047] like Figure 2As shown, in the high-voltage DC direct-connected energy storage valve architecture, a neutral point grounding resistor cabinet is installed at the middle position. Detecting the current in this cabinet can determine whether a submodule (such as SM#1-SM#2n in the diagram) has a grounding fault. The cause of the fault can be analyzed through the fault data waveform. Because the energy storage valve grounding current bandwidth is very wide, reaching up to 20kHz, and the grounding current is normally DC, switching measurement ranges cannot effectively guarantee data continuity if continuous data acquisition is required. Furthermore, because the submodule voltage is very high, for example, a 1500V submodule with a neutral point grounding resistor cabinet resistance of 1KΩ, the current is approximately 1.5A. The grounding current is largest when a grounding fault occurs at the furthest point on the neutral point side, SM#1 or SM#2n. When the number of submodules is large, the grounding current I = N * 1.5A, reaching the order of hundreds of amperes. Therefore, the current generated by a grounding fault is approximately between 1.5A and hundreds of amperes. However, during normal operation, the leakage current of the neutral point grounding is very small, about tens of mA. Therefore, the current dynamic range during grounding fault detection in the high voltage DC direct-connected energy storage valve is very wide, reaching more than a thousand times, making it very difficult to collect accurate current values.
[0048] To address the aforementioned problems, embodiments of this application propose a current detection device, such as... Figure 3 As shown, the current detection device includes: a current sensing device 30, a voltage divider circuit 31, and a control circuit 32.
[0049] The current sensing device 30 is used to acquire the induced current of the circuit to be tested.
[0050] The voltage divider circuit 31 is connected to the current sensing device 30. The voltage divider circuit 31 is used to determine at least a first voltage divider and a second voltage divider based on the induced current obtained by the current sensing device. The first voltage divider is greater than the second voltage divider.
[0051] The control circuit 32 is used to determine the first current value of the circuit to be tested based on the first voltage divider voltage and the second voltage divider voltage determined by the voltage divider circuit.
[0052] Among them, the current sensing device 30 can be a zero-flux current sensor. The zero-flux current sensor is a current sensing device based on the principles of magnetic modulation and magnetic balance. It utilizes the mechanism of alternating saturation of a high-permeability iron core under saturation excitation of an alternating magnetic field to quickly modulate the primary current of the circuit under test to the secondary coil through the ampere-turn principle. This causes the magnetic field generated by the induced current output by the secondary coil to cancel out the magnetic field generated by the primary current. Therefore, the induced current of the secondary coil, combined with the number of turns of the primary and secondary coils, can accurately reflect the magnitude of the current in the circuit under test.
[0053] When calculating the measured current based on the current in the secondary winding and the turns ratio of the winding, if the number of turns in the secondary winding is N1, the number of turns in the primary winding on the side of the measured current is N2, and the induced current in the secondary winding, i.e. the second current value, is I2, then the first current value I1 to be detected can be calculated by the following formula: I1=N1*I2 / N2.
[0054] To achieve high-precision acquisition of the second current value, a voltage divider circuit is used to achieve two independent and non-interfering acquisition levels, enabling different amplification ratios. The voltage divider circuit in this embodiment may include a first voltage divider resistor RM1 and a second voltage divider resistor RM2, connected in series. The induced current detected by the current sensing device flows sequentially into the first voltage divider resistor RM1 and the second voltage divider resistor RM2, forming a first voltage divider voltage and a second voltage divider voltage across RM1 and RM2, respectively. Not limited to two voltage dividers, three or more voltage dividers can be determined based on the induced current.
[0055] The first voltage divider resistor RM1 and the second voltage divider resistor have different resistance values, resulting in different voltage drops generated by the induced current in the first and second voltage divider resistors RM1 and RM2, thus adapting to different current detection requirements. For example, the first voltage divider resistor RM1 can be larger than the second voltage divider resistor RM2, resulting in a higher first voltage divider voltage generated by the first resistor RM1 than by the second voltage divider resistor RM2. In this case, if the first current value of the circuit under test is small, the larger second voltage divider voltage allows for a more accurate determination of the first current value I1. Conversely, if the first current value of the circuit under test is large, the smaller first voltage divider voltage effectively adapts to high current detection requirements.
[0056] The control circuit 32 is used to determine the first current value I1 of the circuit to be detected based on the first voltage divider and the second voltage divider. The control circuit 32 may include an analog-to-digital converter 320 and a processor 321. The processor 321 may include an ARM processor, an FPGA processor, or a microcontroller. The analog-to-digital converter 320 is used to convert the analog first voltage divider into a numerical value and the analog second voltage divider into a numerical value. The processor 321 can determine the induced current of the current sensing device, i.e., the second current value, based on the converted first and second voltage dividers, combined with the first and second voltage divider resistors.
[0057] For example, if the first voltage divider is U1, the second voltage divider is U2, the first voltage divider resistor is RM1, and the second voltage divider resistor is RM2, then the induced current value of the circuit under test, I3 = U1 / RM1, can be estimated based on the first voltage divider voltage U1 and the first voltage divider resistor RM1. Similarly, the induced current value of the circuit under test, I4 = U2 / RM2, can be estimated based on the second voltage divider voltage U2 and the second voltage divider resistor RM2. The magnitude of either the third or fourth current value can be used to determine the first current value of the circuit under test.
[0058] To avoid frequent switching between the third and fourth current values due to current fluctuations, a hysteresis interval can be set. This hysteresis interval is determined based on a first current threshold and a second current threshold. The first current threshold is less than the second current threshold. If either the third or fourth current value is less than the first current threshold, the fourth current value is used as the second current value to determine the first current value. If either the third or fourth current value is greater than the second current threshold, the third current value is used as the second current value to determine the first current value. If the currently selected third current value is less than or equal to the second current threshold and greater than or equal to the first current threshold, the previously selected third current value can be retained as the second current value to determine the first current value of the circuit under test. Similarly, if the currently selected fourth current value is less than or equal to the second current threshold and greater than or equal to the first current threshold, the previously selected fourth current value can be retained as the second current value to determine the first current value of the circuit under test.
[0059] In order to more reliably collect current over a wider range, such as Figure 4 As shown, the current detection device in this embodiment may further include a voltage amplification circuit 33. This voltage amplification circuit 33 includes a first voltage amplification circuit 330 and a second voltage amplification circuit 331, wherein the first voltage amplification circuit 330 amplifies a first voltage divider voltage, and the second voltage amplification circuit amplifies a second voltage divider voltage.
[0060] The first voltage amplifier circuit 330 and the second voltage amplifier circuit 331 can be operational amplifiers. The first voltage amplifier circuit 330 includes a first gain setting resistor RG1, and the second voltage amplifier circuit 331 includes a second gain setting resistor RG2. The first voltage divider voltage is used as the common-mode voltage of the first voltage amplifier circuit 330, and the second voltage divider voltage is used as the common-mode voltage of the second voltage amplifier circuit 331. The amplification factor of the first voltage amplifier circuit 330 can be adjusted by the first gain setting resistor RG1, and the amplification factor of the second voltage amplifier circuit 331 can be adjusted by the second gain setting resistor RG2, so that the voltage amplifier circuit 330 can operate more reliably and reduce distortion when entering saturation.
[0061] After voltage amplification using a voltage amplifier circuit, the third and fourth current values can be estimated based on the first amplified voltage U1' and the second amplified voltage U2', respectively.
[0062] Assuming the voltage amplification factor of the first voltage amplifier circuit is X1, and the voltage amplification factor of the second voltage amplifier circuit is X2, then the first voltage divider voltage U1 = U1' / X1 can be determined based on the first amplified voltage U1', and correspondingly, the second voltage divider voltage U2 = U2' / X2 can be determined based on the second amplified voltage U2'. Figure 3 Similarly, the third current value I3 can be expressed as: I3 = U1 / RM1, and the fourth current value I4 can be expressed as: I4 = U2 / RM2, where RM1 is the first voltage divider resistor in the first voltage divider circuit, and RM2 is the second voltage divider resistor in the second voltage divider circuit. Based on the same or similar calculation method, the control circuit can determine the second current value induced by the circuit under test according to the third current value and the fourth current value.
[0063] In this embodiment, before detection, the current detection device can set the current in the circuit to be detected to a predetermined current, and obtain a first current value based on the predetermined current. According to the predetermined current and the first current value, a calibration coefficient is determined, and the first current value is corrected using the calibration coefficient to obtain a calibrated current value. For example, the correspondence between the first current value and the preset current can be fitted to multiple line segments, and the parameters representing the direction of each line segment can be determined as calibration coefficients. For example, a linear equation can be expressed as y = kx + b, and calibration coefficients k and b can be determined to obtain the correspondence between the preset current and the first current value.
[0064] Figure 5 The diagram shown is a schematic representation of an implementation flow for a control circuit to determine the first current value of a line to be detected, as provided in an embodiment of this application. Details are as follows:
[0065] In S501, the third current value induced by the circuit under test is estimated based on the first voltage divider detected by the current detection device, and the fourth current value induced by the circuit under test is estimated based on the second voltage divider detected by the current detection device.
[0066] The voltage divider detected by the current detection device (including the first voltage divider U1 and the second voltage divider U2) can be... Figure 3 The voltage divider shown or Figure 4 The voltage divider voltages are shown. Based on the determined first voltage divider voltage U1 and second voltage divider voltage U2, and in conjunction with the first voltage divider resistor RM1 and the second voltage divider resistor RM2, the third current value I3 = U1 / RM1 and the fourth current value I4 = U2 / RM2 can be determined.
[0067] In S502, the third current value or the fourth current value is selected to determine the second current value induced by the circuit to be detected based on the magnitude of the third current value or the fourth current value.
[0068] Because the accuracy of the third and fourth current values determined by the first and second voltage divider circuits differs depending on the current, the third or fourth current value must be compared with the current threshold value when selecting it as the second current value for calculation. If the third or fourth current value is greater than the current threshold value, the third current value is used as the second current value. If the third or fourth current value is less than the current threshold value, the fourth current value is used as the second current value.
[0069] To avoid frequent switching between the third and fourth current values due to current fluctuations, a hysteresis interval can be set. This hysteresis interval is determined based on a first current threshold and a second current threshold. The first current threshold is less than the second current threshold. If either the third or fourth current value is less than the first current threshold, the fourth current value is used as the second current value to determine the first current value. If either the third or fourth current value is greater than the second current threshold, the third current value is used as the second current value to determine the first current value. If the currently selected third current value is less than or equal to the second current threshold and greater than or equal to the first current threshold, the previously selected third current value can be retained as the second current value to determine the first current value of the circuit under test. Similarly, if the currently selected fourth current value is less than or equal to the second current threshold and greater than or equal to the first current threshold, the previously selected fourth current value can be retained as the second current value to determine the first current value of the circuit under test.
[0070] That is, if the third current value or the fourth current value is greater than or equal to the first current threshold and less than or equal to the second current threshold, the second current value induced by the circuit to be tested is determined according to the previously selected third current value or the fourth current value.
[0071] Figure 6 A schematic diagram of a current selection process provided in this application embodiment is described in detail below:
[0072] In S601, the second current value I2 is assigned the value of the third current value I3.
[0073] During the initialization phase, the third current value I3 or the fourth current value I4 can be assigned as the second current value I2. This diagram uses the assignment of the third current value I3 as an example for illustration.
[0074] In S602, it is determined whether the third current value I3 is greater than the second current threshold Ith2.
[0075] If the third current value I3 is greater than the second current threshold Ith2, then execute S605; otherwise, execute S603 and assign the second current value I2 to the third current value I3.
[0076] In S604, it is determined whether the third current value I3 is less than the first current threshold Ith1.
[0077] If the third current value I3 is less than the first current threshold Ith1, then in step S605, the second current value I2 is assigned the fourth current value I4. Otherwise, return to step S604.
[0078] In S606, it is determined whether the fourth current value I4 is greater than the second current threshold Ith2.
[0079] If the fourth current value I4 is greater than the second current threshold Ith2, return to S602; otherwise, return to S605.
[0080] By using the above current selection method, the second current value can be automatically matched with a more accurate third or fourth current value according to the magnitude of the current in the line under test, thereby improving the current detection accuracy of the system and facilitating the acquisition of a continuous and accurate second current value, which in turn leads to an accurate first current value in the line under test.
[0081] In S503, the first current value of the circuit to be detected is determined based on the second current value and the sensing coefficient of the current sensing device.
[0082] Assuming the current sensing device is a zero-flux current sensor, the first current value of the circuit to be detected can be determined based on the number of turns of the primary and secondary windings of the zero-flux current sensor, combined with the automatically determined second current value.
[0083] The zero flux current sensor can calculate the measured current based on the current in the secondary winding and the turns ratio of the winding. If the number of turns in the secondary winding is N1 and the number of turns in the primary winding on the side of the measured current is N2, and the induced current in the secondary winding, i.e. the second current value, is I2, then the first current value I1 to be detected can be calculated by the following formula: I1 = N1 * I2 / N2.
[0084] Furthermore, in this embodiment, before testing, the current in the circuit to be tested can be set to a predetermined current, and a first current value can be obtained based on the predetermined current. According to the predetermined current and the first current value, calibration coefficients of the device are determined, and the first current value is corrected using these calibration coefficients to obtain a calibration current value. For example, the correspondence between the first current value and the preset current can be fitted to multiple line segments, and the parameters representing the direction of each line segment can be determined as calibration coefficients. For example, a linear equation can be expressed as y = kx + b, and calibration coefficients k and b can be determined to obtain the correspondence between the preset current and the first current value.
[0085] Furthermore, in this embodiment, to improve the reliability of the measured data, multiple sets of current sensing devices are typically used for measurement, such as three sets of current sensing devices. Since a single current sensing device in this embodiment only requires one current sensing device, compared to the existing structure where a single current device includes at least two current sensing devices, the use of current sensing devices can be greatly reduced, system wiring can be simplified, and product reliability can be improved.
[0086] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.
[0087] Figure 7 This is a schematic diagram of a current detection device provided in an embodiment of this application. The device includes:
[0088] The current value detection unit 701 is used to estimate the third current value induced by the circuit under test based on the first voltage divider detected by the current detection device according to any one of claims 1-7, and to estimate the fourth current value induced by the circuit under test based on the second voltage divider detected by the current detection device.
[0089] The current value selection unit 702 is used to select the third current value or the fourth current value to determine the second current value induced by the circuit to be detected based on the magnitude of the third current value or the fourth current value.
[0090] The first current value determination unit 703 is used to determine the first current value of the circuit to be detected based on the second current value and the sensing coefficient of the current sensing device.
[0091] Figure 7 The current detection device shown is, with Figure 5 The current detection method shown corresponds to this.
[0092] Figure 8 This is a schematic diagram of a current detection device provided in an embodiment of this application. Figure 8As shown, the current detection device 8 of this embodiment includes: a processor 80, a memory 81, and a computer program 82, such as a current detection program, stored in the memory 81 and executable on the processor 80. When the processor 80 executes the computer program 82, it implements the steps in the various current detection method embodiments described above. Alternatively, when the processor 80 executes the computer program 82, it implements the functions of each module / unit in the various device embodiments described above.
[0093] For example, the computer program 82 may be divided into one or more modules / units, which are stored in the memory 81 and executed by the processor 80 to complete this application. The one or more modules / units may be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of the computer program 82 in the current detection device 8.
[0094] The current detection device may include, but is not limited to, a processor 80 and a memory 81. Those skilled in the art will understand that... Figure 8 This is merely an example of a current sensing device 8 and does not constitute a limitation on the current sensing device 8. It may include more or fewer components than shown, or combine certain components, or different components. For example, the current sensing device may also include input / output devices, network access devices, buses, etc.
[0095] The processor 80 may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor.
[0096] The memory 81 can be an internal storage unit of the current detection device 8, such as a hard disk or RAM of the current detection device 8. The memory 81 can also be an external storage device of the current detection device 8, such as a plug-in hard disk, Smart Media Card (SMC), Secure Digital (SD) card, or Flash Card equipped on the current detection device 8. Furthermore, the memory 81 can include both internal and external storage units of the current detection device 8. The memory 81 is used to store the computer program and other programs and data required by the current detection device. The memory 81 can also be used to temporarily store data that has been output or will be output.
[0097] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.
[0098] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.
[0099] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.
[0100] In the embodiments provided in this application, it should be understood that the disclosed devices / terminal equipment and methods can be implemented in other ways. For example, the device / terminal equipment embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling or direct coupling or communication connection may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.
[0101] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.
[0102] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.
[0103] If the integrated module / unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments can also be implemented by hardware related to computer program instructions. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying the computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc. It should be noted that the content included in the computer-readable medium can be appropriately added or removed according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electrical carrier signals and telecommunication signals.
[0104] In addition, this application also provides a computer program product that, when run on a computer, causes the computer to execute the methods in the above-described implementations.
[0105] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.
Claims
1. A current detection device, characterized in that, The current detection device includes: a current sensing device, a voltage divider circuit, and a control circuit; The current sensing device is used to acquire the induced current of the circuit under test. The voltage divider circuit is used to determine, based on the induced current, at least a first voltage divider voltage and a second voltage divider voltage, wherein the first voltage divider voltage is greater than the second voltage divider voltage. The control circuit is used to determine the first current value of the circuit to be tested based on the first voltage divider and the second voltage divider.
2. The device according to claim 1, characterized in that, The current detection device further includes a voltage amplification circuit, which comprises a first voltage amplification circuit and a second voltage amplification circuit, wherein: The first voltage amplifier circuit is used to amplify the first voltage divider to obtain the first amplified voltage; The second voltage amplifier circuit is used to amplify the second voltage divider to obtain the second amplified voltage; The control circuit is used to determine the first current value of the circuit to be tested based on the first amplified voltage and the second amplified voltage.
3. The device according to claim 2, characterized in that, The first voltage amplifier circuit includes a first operational amplifier, the first voltage divider voltage is used as the common-mode voltage of the first operational amplifier, and the first operational amplifier outputs a first amplified voltage; The second voltage amplifier circuit includes a second operational amplifier, the second voltage divider is used as the common-mode voltage of the second operational amplifier, and the second operational amplifier outputs a second amplified voltage.
4. The device according to claim 3, characterized in that, The voltage divider circuit includes a first voltage divider resistor and a second voltage divider resistor, the first voltage divider resistor and the second voltage divider resistor are connected in series, the induced current of the circuit under test generates a first voltage divider voltage when it passes through the first voltage divider resistor, and the induced current of the circuit under test generates a second voltage divider voltage when it passes through the second voltage divider resistor; The control circuit is used to determine the second current value induced by the circuit under test based on the resistance value of the first voltage divider resistor, the resistance value of the second voltage divider resistor, the amplification factor of the first operational amplifier, the amplification factor of the second operational amplifier, the first amplification voltage, and the second amplification voltage, and to determine the first current value of the circuit under test based on the second current value induced by the circuit under test.
5. The device according to claim 4, characterized in that, The current sensing device is a zero-flux current sensor, and the control circuit is used to determine the first current value of the circuit under test based on the second current value sensed by the circuit under test, combined with the number of turns of the primary and secondary windings of the zero-flux current sensor.
6. The device according to claim 4, characterized in that, The control circuit is used to estimate the third current value induced by the circuit under test based on the resistance value of the first voltage divider resistor, the amplification factor of the first operational amplifier, and the first amplification voltage; to estimate the fourth current value induced by the circuit under test based on the resistance value of the second voltage divider resistor, the amplification factor of the second operational amplifier, and the second amplification voltage; and to determine the second current value induced by the circuit under test based on the third current value, the fourth current value, and a preset current threshold.
7. The device according to claim 6, characterized in that, The control circuit is used for: If the third current value or the fourth current value is less than a preset first current threshold, the second current value induced by the circuit to be detected is determined based on the fourth current value. If the third current value or the fourth current value is greater than the preset second current threshold, the second current value induced by the circuit to be detected is determined based on the third current value. If the third current value or the fourth current value is greater than or equal to the first current threshold and less than or equal to the second current threshold, the second current value induced by the circuit to be detected shall continue to be determined according to the previously selected third current value or the fourth current value. Wherein, the first current threshold is less than the second current threshold.
8. A current detection method, characterized in that, The method includes: The first voltage divider voltage detected by the current detection device according to any one of claims 1-7 is used to estimate the third current value induced in the circuit under test, and the second voltage divider voltage of the current detection device is used to estimate the fourth current value induced in the circuit under test. Based on the magnitude of the third current value or the fourth current value, the third current value or the fourth current value is selected to determine the second current value induced by the circuit to be detected; Based on the second current value and the sensing coefficient of the current sensing device, the first current value of the circuit to be tested is determined.
9. The method according to claim 8, characterized in that, Based on the magnitude of the third current value or the fourth current value, the method of selecting the third current value or the fourth current value to determine the second current value induced in the circuit to be detected includes: If the third current value or the fourth current value is less than a preset first current threshold, the second current value induced by the circuit to be detected is determined based on the fourth current value. If the third current value or the fourth current value is greater than the preset second current threshold, the second current value induced by the circuit to be detected is determined based on the third current value. If the third current value or the fourth current value is greater than or equal to the first current threshold and less than or equal to the second current threshold, the second current value induced by the circuit to be detected shall continue to be determined according to the previously selected third current value or the fourth current value. Wherein, the first current threshold is less than the second current threshold.
10. The method according to claim 8, characterized in that, The current sensing device is a zero-flux current sensor; Based on the second current value and the sensing coefficient of the current sensing device, the first current value of the circuit to be detected is determined, including: Based on the number of turns of the primary and secondary windings of the zero magnetic current sensor, and in conjunction with the second current value, the first current value of the circuit to be tested is determined.
11. The method according to any one of claims 8-10, characterized in that, Before estimating the third current value induced in the circuit under test based on the first voltage divider voltage detected by the current detection device, and estimating the fourth current value induced in the circuit under test based on the second voltage divider voltage detected by the current detection device, the method further includes: The current is detected according to the predetermined current set for the circuit to be tested, and the first current value corresponding to the predetermined current is obtained. The calibration coefficient is determined based on the predetermined current and the first current value; After determining the first current value of the circuit to be detected based on the second current value and the induction coefficient of the current sensing device, the method further includes: The first current value is calibrated according to the calibration coefficient to obtain the calibration current value.
12. A current detection device, characterized in that, The device includes: A current value detection unit is used to estimate a third current value induced in the circuit under test based on a first voltage divider detected by the current detection device according to any one of claims 1-7, and to estimate a fourth current value induced in the circuit under test based on a second voltage divider detected by the current detection device. A current value selection unit is used to select the third current value or the fourth current value to determine the second current value induced by the circuit to be detected based on the magnitude of the third current value or the fourth current value. The first current value determination unit is used to determine the first current value of the circuit to be detected based on the second current value and the sensing coefficient of the current sensing device.
13. A current detection device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it causes the current detection device to implement the method as described in any one of claims 8-11.
14. A computer program product comprising computer program instructions, characterized in that, When the computer program is run, the method as described in any one of claims 8-11 is performed.