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CN-122017301-A - Rogowski coil integrator and current sensor

CN122017301ACN 122017301 ACN122017301 ACN 122017301ACN-122017301-A

Abstract

The invention relates to the technical field of current measurement and discloses a Rogowski coil integrator and a current sensor, wherein the Rogowski coil integrator comprises an in-phase integrating circuit and a low-pass amplifying circuit, the in-phase integrating circuit comprises a first operational amplifier, the in-phase input end of the first operational amplifier is connected with a Rogowski coil, the low-pass amplifying circuit is connected between the anti-phase input end of the first operational amplifier and the output end of the first operational amplifier, and the low-pass amplifying circuit is used for feeding back direct current output of the in-phase integrating circuit to the anti-phase input end of the first operational amplifier and carrying out low-pass filtering on a low-frequency signal. The invention can improve the dynamic range of the rogowski coil integrator and realize the expansion of the low-frequency bandwidth of the integrator.

Inventors

  • SHI QIBIAO
  • FAN TAO

Assignees

  • 中国科学院电工研究所

Dates

Publication Date
20260512
Application Date
20251222

Claims (8)

  1. 1. The Rogowski coil integrator is characterized by comprising an in-phase integrating circuit and a low-pass amplifying circuit; The in-phase integrating circuit comprises a first operational amplifier, wherein the in-phase input end of the first operational amplifier is connected with the Rogowski coil, and the low-pass amplifying circuit is connected between the inverting input end of the first operational amplifier and the output end of the first operational amplifier; The low-pass amplifying circuit is used for feeding back the direct current output of the in-phase integrating circuit to the inverting input end of the first operational amplifier and performing low-pass filtering on a low-frequency signal.
  2. 2. The rogowski coil integrator according to claim 1, wherein the low-pass amplifying circuit comprises a second operational amplifier, a third resistor, a first low-pass filter circuit and a feedback channel circuit, a non-inverting input terminal of the second operational amplifier is connected with an output terminal of the first operational amplifier through the first low-pass filter circuit, the feedback channel circuit is connected between an inverting input terminal of the second operational amplifier and an output terminal of the second operational amplifier, and an output terminal of the second operational amplifier is connected with the inverting input terminal of the first operational amplifier through the third resistor.
  3. 3. The rogowski coil integrator of claim 2, wherein the first low pass filter circuit comprises a fifth resistor and a fourth capacitor, a first end of the fifth resistor is connected to the output of the first operational amplifier, a second end of the fifth resistor is connected to the first end of the fourth capacitor and the non-inverting input of the second operational amplifier, respectively, and a second end of the fourth capacitor is grounded.
  4. 4. A rogowski coil integrator according to claim 3, wherein the feedback path circuit comprises a sixth resistor, a seventh resistor and a fifth capacitor, a first end of the sixth resistor is grounded, a second end of the sixth resistor is connected to a first end of the seventh resistor and an inverting input of the second operational amplifier, respectively, a second end of the seventh resistor is connected to an output of the second operational amplifier, and the fifth capacitor and the seventh resistor are connected in parallel.
  5. 5. The rogowski coil integrator of claim 1, further comprising a high-pass output circuit having an input coupled to the output of the first operational amplifier, the output of the high-pass output circuit being coupled to a signal output of the integrator.
  6. 6. The rogowski coil integrator of claim 5, wherein the high-pass output circuit comprises a third capacitor and a fourth resistor, a first end of the third capacitor is connected to the output of the first operational amplifier, a second end of the third capacitor is connected to a first end of the fourth resistor and a signal output of the integrator, respectively, and a second end of the fourth resistor is grounded.
  7. 7. The rogowski coil integrator of claim 1, where the in-phase integrating circuit further comprises a first resistor, a second resistor, a first capacitor and a second capacitor, the first end of the first resistor is connected to the rogowski coil, the second end of the first resistor is connected to the first end of the first capacitor and the in-phase input end of the first operational amplifier, the second end of the first capacitor is grounded, the first end of the second resistor is grounded, the second end of the second resistor is connected to the first end of the second capacitor and the inverting input end of the first operational amplifier, and the second end of the second capacitor is connected to the output end of the first operational amplifier.
  8. 8. A current sensor comprising a rogowski coil and a rogowski coil integrator according to any of claims 1 to 7, the output of the rogowski coil being connected to the rogowski coil integrator.

Description

Rogowski coil integrator and current sensor Technical Field The invention relates to the technical field of current measurement, in particular to a rogowski coil integrator and a current sensor. Background Rogowski Coil (Rogowski Coil) is a current measuring device based on the principle of electromagnetic induction, in which the output signal of the Rogowski Coil is proportional to the derivative of the measured current. Therefore, the original current signal must be restored by an integration process. The implementation of this integration directly determines the accuracy, stability and dynamic performance of the overall measurement system. Conventional integration schemes mainly include two types, analog integration and digital integration. Conventional integration schemes mainly include two types, analog integration and digital integration. The analog integrator is usually constructed based on an operational amplifier and an RC network, has the advantages of strong instantaneity and low delay, but is easily influenced by factors such as direct current drift, temperature drift and element aging, so that the problem of saturation or error accumulation of an integration result is caused. The digital integrator is realized by the high-speed ADC and the digital signal processor, can correct partial errors through an algorithm, has flexible programmability, is easily limited by sampling rate and quantization errors in high-frequency measurement, and has higher system complexity and cost. Currently, the circuits of rogowski coil integrator mainly include an inverting integrator circuit and an in-phase integrator circuit. Whether an inverting integrator circuit or an in-phase integrator circuit, a significant dc bias is generated at the output of the op-amp, resulting in a limited output dynamic range, while the low-frequency bandwidth of the integrator is limited. Disclosure of Invention The invention provides a rogowski coil integrator and a current sensor, which are used for solving the technical problems that the output dynamic range of the rogowski coil integrator is limited and the low-frequency bandwidth is limited. In a first aspect, the present invention provides a rogowski coil integrator comprising an in-phase integrating circuit and a low pass amplifying circuit; The in-phase integrating circuit comprises a first operational amplifier, wherein the in-phase input end of the first operational amplifier is connected with the Rogowski coil, and a low-pass amplifying circuit is connected between the inverting input end of the first operational amplifier and the output end of the first operational amplifier; The low-pass amplifying circuit is used for feeding back the direct current output of the in-phase integrating circuit to the inverting input end of the first operational amplifier and performing low-pass filtering on the low-frequency signal. In some alternative embodiments, the low-pass amplifying circuit includes a second operational amplifier, a third resistor, a first low-pass filter circuit and a feedback channel circuit, wherein the non-inverting input end of the second operational amplifier is connected with the output end of the first operational amplifier through the first low-pass filter circuit, the feedback channel circuit is connected between the inverting input end of the second operational amplifier and the output end of the second operational amplifier, and the output end of the second operational amplifier is connected with the inverting input end of the first operational amplifier through the third resistor. In some alternative embodiments, the first low-pass filter circuit includes a fifth resistor and a fourth capacitor, a first end of the fifth resistor is connected to the output end of the first operational amplifier, a second end of the fifth resistor is connected to the first end of the fourth capacitor and the non-inverting input end of the second operational amplifier, and a second end of the fourth capacitor is grounded. In some alternative embodiments, the feedback channel circuit includes a sixth resistor, a seventh resistor, and a fifth capacitor, the first end of the sixth resistor is grounded, the second end of the sixth resistor is connected to the first end of the seventh resistor and the inverting input end of the second operational amplifier, the second end of the seventh resistor is connected to the output end of the second operational amplifier, and the fifth capacitor and the seventh resistor are connected in parallel. In some alternative embodiments, the rogowski coil integrator further comprises a high-pass output circuit, an input of the high-pass output circuit being connected to the output of the first operational amplifier, and an output of the high-pass output circuit being connected to the signal output of the integrator. In some alternative embodiments, the high-pass output circuit includes a third capacitor and a fourth resistor, a first end of the thi