Diverter-based dual-path conditioning current sensor

Abstract

The invention relates to the field of current sensors, and discloses a shunt-based two-way conditioning current sensor, the sensor comprises a shunt detection module and a Hall detection module, the shunt detection module is used for connecting a shunt in series in a loop to be detected, when current flows through the shunt, tiny voltage difference is generated, and the Hall detection module is used for detecting the current flowing through the shunt. Isolating, amplifying, raising and calibrating the voltage difference, and substituting the voltage difference into a UI fitting formula to obtain a current value to be measured; the Hall detection module and the diverter detection module carry out detection synchronously, and a measured voltage signal is output after being amplified, raised and calibrated. By adopting a mode of double-path independent measurement and synchronous comparison of the shunt sensor and the Hall sensor, measurement errors can be detected in real time, and an on-line self-diagnosis function is realized. According to the shunt-based dual-path conditioning current sensor provided by the invention, the Hall element and shunt dual-path conditioning are combined, so that common cause failure is avoided, and the measurement accuracy and reliability are improved; two-way synchronous detection is adopted, faults can be judged when deviation is large, modules can be replaced conveniently, and the self-diagnosis capacity and safety are enhanced.

Description

Technical Field

[0001] This invention relates to the field of current sensor technology, and more specifically, to a shunt-based dual-path conditioning current sensor. Background Technology

[0002] In industrial automation and power systems, high-precision current measurement is essential for reliable system monitoring, fault diagnosis, and energy efficiency management. Traditional solutions often lack online self-diagnosis and fault detection capabilities, making it difficult to meet the increasingly stringent safety and intelligence requirements of modern industry. While shunt-based sensors are favored for their simple structure and low cost, relying solely on a fixed-gain signal conditioning link makes it difficult to simultaneously cover a wide dynamic range and maintain high measurement accuracy.

[0003] Currently, mainstream current sensors based on shunts generally adopt a fixed gain conditioning circuit architecture, which lacks online self-diagnosis and fault detection, and cannot detect its own drift or failure in real time. Once an anomaly occurs, it can only passively wait for system-level alarms. To make up for this deficiency, some manufacturers have tried to place a shunt and a Hall chip in the same package to form a "dual sensing element" solution.

[0004] However, these integrated devices often omit necessary signal processing steps such as differential amplification, isolation amplification, and digital calibration, making the millivolt-level output of the Hall channel extremely susceptible to electromagnetic noise, temperature drift, and common-mode interference, resulting in a decrease in overall accuracy. The shunt must be connected in series with the high-voltage main circuit (primary side), while the Hall detection is located in the safe low-voltage area (secondary side). If the two are simply combined, there is no reliable isolation barrier between the high and low voltage, which may lead to a series of serious consequences such as electric shock, fire, equipment damage, and a significant reduction in system reliability. Summary of the Invention

[0005] This invention provides a dual-path conditioning current sensor based on a shunt, which solves the technical problems of errors that cannot be self-diagnosed and increased danger in related technologies.

[0006] This invention provides a dual-path conditioning current sensor based on a shunt, comprising: The shunt sensor is connected in series in the circuit under test. When current flows through the shunt, a voltage difference will be generated across the shunt. By isolating and amplifying the voltage difference signal, the current value can be obtained by substituting it into the UI fitting formula. Hall sensors sense current through the Hall effect. When current flows through a shunt, the Hall element generates a set of voltage signals. The voltage is amplified, raised, and calibrated, and then output synchronously with the shunt sensor. The current value is then calculated and compared. By employing a dual-channel independent measurement and synchronous comparison method using a shunt sensor and a Hall sensor, measurement errors can be detected in real time, enabling online self-diagnosis.

[0007] As a further optimization of the present invention, the shunt sensor includes: The circuit consists of a shunt, an isolator, a differential amplifier, and a conditioning module. The voltage signal generated after current is applied to the shunt is calibrated by the isolator, the differential amplifier, and the conditioning module before being output.

[0008] As a further optimization of the present invention, the Hall sensor includes: The system consists of a Hall element, a differential amplifier, and a conditioning module. The Hall element senses the voltage at the shunt, and the voltage is output after being calibrated by the differential amplifier and the conditioning module.

[0009] As a further optimization of the present invention, the voltage collected by the Hall element is amplified and then output at 2.5V.

[0010] As a further optimization of the present invention, the Hall sensor is a low-voltage detection device. When the shunt sensor measures the current, it needs to be connected in series with the high-voltage system. The high-voltage area of ​​the shunt is effectively isolated from the low-voltage area through the isolation module.

[0011] As a further optimization of the present invention, the two outputs are calibrated through a conditioning module to make the outputs more reliable.

[0012] As a further optimization of the present invention, the voltage signal collected by the shunt is linked to four commutation resistors, making the signal direction flexibly adjustable.

[0013] The beneficial effects of this invention are as follows: 1. Redundant design enhances the system's self-diagnostic capability. By employing dual-channel independent measurement and synchronous comparison using a shunt sensor and a Hall sensor, measurement errors can be detected in real time, enabling the device to perform online self-diagnosis. This effectively solves the problem that traditional sensors cannot diagnose errors on their own, greatly improving the reliability of measurement results and reducing the risk of system malfunctions due to sensor failures.

[0014] 2. Dual-channel conditioning and calibration enhances system reliability. The combined design of the Hall sensor and shunt sensor, along with dual-channel conditioning and calibration, compensates for sensor temperature drift and component errors, ensuring high-precision measurement across the entire measurement range. This avoids common-cause failures and improves detection accuracy and reliability. In industrial motor or servo control applications, accurate current measurement is a critical part of the control loop, and the high-precision characteristics of this sensor meet the stringent requirements for current measurement accuracy in such scenarios.

[0015] 3. High and low voltage isolation design improves system safety. The Hall sensor is a low-voltage detection device, and the shunt sensor is a high-voltage detection device. The isolation module provides separate power supplies to the high-voltage and low-voltage areas of the shunt, eliminating power coupling interference between the high and low voltage sides and effectively isolating them, giving the system good insulation. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of a dual-path conditioning current sensor based on a shunt proposed in this invention.

[0017] Figure 2 This is a circuit diagram of the shunt sensor detection channel in this invention.

[0018] Figure 3 This is a circuit diagram of the Hall sensor detection channel in this invention. Detailed Implementation

[0019] The subject matter described herein will now be discussed with reference to exemplary embodiments. It should be understood that these embodiments are discussed only to enable those skilled in the art to better understand and implement the subject matter described herein, and changes may be made to the function and arrangement of the elements discussed without departing from the scope of this specification. Various processes or components may be omitted, substituted, or added as needed in the examples. Furthermore, features described in some examples may be combined in other examples.

[0020] Example 1 like Figure 1 As shown in the embodiment of the present invention, a dual-path conditioning current sensor based on a shunt includes: The shunt sensor includes a shunt, an isolator, a differential amplifier, and a conditioning module. The shunt is connected in series in the circuit under test. The voltage signal collected at both ends of the shunt is output after passing through the isolator, the differential amplifier, and the conditioning module.

[0021] Detection principle: When current flows through the shunt, a voltage difference is generated across the shunt. The small voltage difference is isolated, amplified, and then output. By detecting the output voltage and dividing it by the amplification factor, the actual voltage across the shunt is obtained. The resistance of the shunt is known, and the current value to be measured can be obtained according to Ohm's law I=U / R.

[0022] The Hall sensor includes a Hall element, a differential amplifier, and a conditioning module. The Hall element senses the voltage across the shunt, which is then amplified by the differential amplifier, calibrated by the conditioning module, and raised to 2.5V by the reference source before being output.

[0023] Detection Principle: Hall sensors detect current based on the Hall effect. When the current being measured passes through a conductor in a magnetic core, a magnetic field is generated around the conductor according to Ampere's law. The strength of this magnetic field is proportional to the magnitude of the current being measured, and the magnetic field lines are concentrated within the magnetic core. A Hall element is placed in the air gap of the magnetic core. The magnetic field passes perpendicularly through the Hall element, causing the charge carriers in the Hall element to deflect under the Lorentz force, generating a Hall voltage in a direction perpendicular to both the current and the magnetic field. The magnitude of the Hall voltage is proportional to the magnetic field strength, i.e., proportional to the current being measured. Substituting these values ​​into the fitting formula for Hall voltage versus detected current, the measured current can be calculated.

[0024] The voltage acquired by the Hall element is amplified and then output at 2.5V, ensuring that the signal is within a positive voltage range suitable for subsequent circuit inputs. This avoids signal truncation or distortion, improves the accuracy of signal acquisition, and enhances the compatibility of the sensor with various data acquisition and processing systems.

[0025] When the measurement results of the Hall sensor and the shunt sensor deviate significantly, the system can be identified as faulty, thereby improving the system's self-diagnostic capability.

[0026] When the shunt is connected to the circuit under test, and the current under test passes through it, the shunt sensor first isolates, amplifies (enhances weak signals), raises (adjusts signal level), and calibrates (corrects errors) the voltage signal it measures in sequence, and finally outputs and converts it into the corresponding current value. At the same time, the Hall sensor senses the current at the shunt sensor in real time, converts the sensed current into a voltage signal, and after being amplified, raised, and calibrated, it keeps synchronized with the output of the shunt sensor. Finally, the current values ​​obtained from the two conversions are compared. By measuring independently and comparing them synchronously, measurement errors can be detected in real time, realizing online self-diagnosis. This solves the problem that traditional sensors cannot diagnose errors on their own, and improves the reliability of measurement.

[0027] Furthermore, there is electrical isolation before and after the shunt test.

[0028] As a further optimization of the present invention, when current flows through the shunt, a small voltage difference is generated across the shunt, and the voltage difference is transmitted to the isolation amplifier after passing through four commutation resistors.

[0029] When current flows through the shunt, the small voltage difference generated across its two ends is processed by four commutation resistors. The commutation resistors can automatically adjust the signal polarity according to the current direction, ensuring that currents in different directions can be converted into signals of the correct polarity and transmitted to subsequent circuits. This avoids measurement errors caused by reverse current and improves the applicability of the sensor under different current conditions.

[0030] Example 2 Based on Example 1: like Figure 2As shown, the shunt sensor detection channel consists of the following: Resistor R1 is a shunt, and the shunt is a low-ohm sampling shunt. R1 is connected in series in the circuit under test. The current under test is calculated by collecting the voltage across R1. Resistors R3, R4, R5, and R6 are commutation resistors. Selecting either R3 and R5 or R4 and R6 can change the direction of the acquired signal. Resistors R8 and R9, together with capacitors C6 and C11, form a low-pass filter; C10 — Filters out common-mode interference; U5—Isolates and amplifies the voltage signals acquired at both ends of the shunt; C4 and C3 — Filtering function to eliminate noise interference; L1—Suppresses and filters common-mode interference signals in the circuit; R13 and R12, together with C13 and C12, form a low-pass filter; R15—Balancing resistor; R16—Balancing resistor; R19 — Feedback resistor, used to adjust the amplification factor; C8—Anti-interference; R14 — Increase bias voltage; C7—Absorbs reflected signals; C15—Filter capacitor, used for interference suppression; U3.1 — Operational amplification, the amplification factor can be adjusted by the ratio of R19 to R15; R24@ and C14—R24@ and C14 constitute a low-pass filter; D1—Electrostatic clamping; U1—Provides a 2.5V reference voltage; R2—Adjusts the input and output current of the reference circuit; R7, R10, R11 — Adjust the output reference voltage; C1 — Filter; U3.2 — Voltage follower, used to stabilize the reference voltage; D4—Overvoltage protection; C16 — Filtering function; Q1—Reverse connection protection circuit; U4—a DC-DC isolated power supply, generates a set of isolation voltages, with the voltages before and after isolation supplying power to the isolation amplifier respectively; C9 — Filtering function; R20 — Current limiting; A shunt resistor R1 is connected in series in the circuit under test. When current flows through the shunt, a small voltage difference is generated across the shunt. This voltage difference is transmitted to the isolation amplifier U5 after passing through four commutation resistors. U5 isolates and amplifies the voltage difference before outputting it to U3.1. The reference chip U1 generates a 2.5V reference voltage. This 2.5V reference voltage is buffered by U3.2 and connected to the positive input terminal of U3.1. When the voltage signal output by U5 is transmitted to U3.1, it is boosted to 2.5V. By detecting the output voltage signal and substituting it into the UI fitting formula, the value of the current to be measured can be obtained.

[0031] like Figure 3 As shown, the Hall sensor detection channel consists of the following: R1—Adjusts the input and output current of the reference circuit; U1—Reference power supply 2.5V R8—Increase bias C3—Filtering U8.2, R9, R10, R11, R12, R12A — Zeroing module, zeroing calibration can be performed by adjusting the values ​​of R12 and R12A; U5—Hall element, used to collect current (U2, R6, R14, Q1, R13, and D1 together form a constant current circuit). U2—Provides a 2.5V reference voltage; R6 — Adjusts the input and output current of the reference circuit; R14 — The current value of the constant current circuit is adjusted by adjusting the resistance value of R14; Q1—Provides a stable current output; R13, D1 — Enables Q1 to quickly enter working state upon power-up; R7—Increases bias; U8.1, R3, R5, R5A — In-phase amplification, full-scale adjustment module; full-scale calibration can be performed by adjusting the values ​​of R15 and R15A. C1 — Filter; C4—Anti-interference; R18, C7-RC filters; When current flows through the shunt, the Hall element will synchronously output a set of voltage signals. The voltage signals are amplified by operational amplifier U8.2 (zeroed) and U8.1 (full-scale) before being output. U2 is a 1.25V reference chip, which, together with Q1, forms a constant current circuit to provide a constant current to the Hall chip. U1 is a 2.5V reference. The voltage collected by the Hall element is amplified by U8.1 and output at 2.5V. By detecting the output voltage signal and substituting it into the UI fitting formula, the value of the current to be measured can be obtained.

[0032] In this invention: I. Dual-channel heterogeneous detection improves reliability The system adopts a dual-channel design with a Hall sensor (non-contact magnetic field detection) and a shunt sensor (direct differential pressure measurement). Through the complementary principle of heterogeneity, the shunt ensures high-precision high-current measurement, while the Hall sensor provides non-contact safety. The dual-channel independent conditioning avoids common-cause failure and significantly improves measurement reliability.

[0033] II. Redundancy Check Enables Intelligent Self-Diagnosis Two sensors synchronously detect the same current, and the results are compared in real time by the MCU. Under normal conditions, the average value is taken to optimize accuracy. Abnormal deviations (such as ±5%) trigger fault alarms, quickly locate the failed module, and the redundancy design ensures that the system can still operate in degraded mode when a single channel fails, thereby improving fault tolerance and maintenance efficiency.

[0034] III. High and low voltage isolation ensures safety The shunt is connected in series with the high-voltage circuit, and the high and low voltage areas are strictly isolated by the isolation amplifier (U5) and the isolation power supply (U4) to block electrical risks. The Hall sensor operates on the low-voltage side and does not require additional isolation. The system complies with industrial safety regulations (such as IEC61010) and has an insulation withstand voltage of several kilovolts, ensuring both accurate measurement and operational safety.

[0035] The embodiments of the present invention have been described above, but the embodiments are not limited to the specific implementation methods described above. The specific implementation methods described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the embodiments described above, all of which are within the protection scope of the embodiments described above.

Claims

1. A dual-path conditioned current sensor based on a shunt, characterized in that, include: The shunt sensor is connected in the circuit under test to isolate, amplify, boost, and calibrate the measured voltage signal, and output the corresponding voltage value. The Hall sensor senses the current at the shunt sensor, converts the current signal of the shunt into a voltage, amplifies, boosts, and calibrates it, and then outputs it synchronously with the shunt sensor. By employing a dual-channel independent measurement and synchronous comparison method using a shunt sensor and a Hall sensor, measurement errors can be detected in real time, enabling online self-diagnosis.

2. The dual-path conditioning current sensor based on a shunt according to claim 1, characterized in that: The shunt sensor includes: The circuit consists of a shunt, an isolator, a differential amplifier, and a conditioning module. Current is passed through the shunt, and the resulting voltage signal is output after passing through the isolator, differential amplifier, and conditioning module.

3. The dual-path conditioning current sensor based on a shunt according to claim 2, characterized in that: Hall sensors include: The system includes a Hall element, a differential amplifier, and a conditioning module. The Hall element collects the voltage at the shunt, which is then processed by the differential amplifier and the conditioning module before being output.

4. The dual-path conditioning current sensor based on a shunt according to claim 3, characterized in that: The voltage collected by the Hall element is amplified and then output at 2.5V.

5. The dual-path conditioning current sensor based on a shunt according to claim 2, characterized in that: There is high and low voltage electrical isolation before and after the shunt.

6. The dual-path conditioning current sensor based on a shunt according to any one of claims 2-5, characterized in that: The conditioning module includes zeroing and full-scale calibration.

7. The dual-path conditioning current sensor based on a shunt according to claim 6, characterized in that: The voltage difference generated when current flows through the shunt is transmitted to the isolation amplifier via four commutation resistors.

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