Rogowski coil current transformer and current measurement system

Abstract

The invention discloses a Rogowski coil current transformer and a current measurement system, and relates to the technical field of current measurement. The Rogowski coil current transformer comprises a Rogowski coil and a signal processing circuit; the differential signal is converted into a differential constant-current signal to be output based on a signal processing circuit; the signal processing circuit comprises an integral amplification module for performing integral amplification on the differential signal based on the integral amplification module; the first direct current component removing module is used for removing a direct current component in the voltage signal after integral amplification based on the first direct current component removing module; the signal adjusting module is used for realizing amplitude in-phase amplification and phase compensation; the single-ended to differential output module is used for generating symmetrical differential voltage signals based on the single-ended to differential output module; and the conversion module is used for converting the symmetrical differential voltage signal into a differential constant current signal and outputting the differential constant current signal based on the conversion module. And through the integral amplification module and the phase compensation module, the differential signal is accurately converted into the current signal, so that the current measurement result is more accurate.

Description

Technical Field

[0001] The present application relates to the technical field of current measurement, and in particular to a Rogowski coil current transformer and a current measurement system. Background Art

[0002] Traditional current transformers have certain limitations in terms of high precision, wide bandwidth and safety; Rogowski coils, as a non-invasive current sensor, have been widely used in modern power systems due to their simple structure, fast response speed and wide frequency range.

[0003] However, the output of the Rogowski coil is a differential signal, which needs to be converted into a practical current or voltage signal through complex signal processing. Summary of the Invention

[0004] To solve the above problems, the present application provides a Rogowski coil current transformer, comprising a Rogowski coil and a signal processing circuit, wherein the signal processing circuit is connected to the Rogowski coil; based on the signal processing circuit, the differential signal output by the Rogowski coil is converted into a differential constant current signal output; the signal processing circuit comprises: an integral amplification module, performing integral amplification on the differential signal based on the integral amplification module; a first DC component removal module, which removes the DC component from the voltage signal after integration and amplification based on the first DC component removal module; A signal conditioning module connected to the first DC component removal module; the signal conditioning module includes an amplitude modulation module and a phase compensation module; the amplitude modulation module implements amplitude in-phase amplification; the phase compensation module performs phase compensation on the signal after the amplitude in-phase amplification; A single-ended to differential output module, the single-ended to differential output module is connected to the signal conditioning module; a symmetrical differential voltage signal is generated based on the single-ended to differential output module; The conversion module converts the symmetrical differential voltage signal into a differential constant current signal for output.

[0005] In an optional embodiment, the integral amplification module includes an integral amplification loop and a compensation loop; integral amplification is implemented based on the integral amplification loop; phase compensation and signal saturation suppression are implemented based on the compensation loop.

[0006] In an optional embodiment, the compensation loop includes a resistor and a capacitor connected in parallel; the resistor is used to suppress DC saturation of the integrator, and the capacitor is used for phase compensation.

[0007] In an optional embodiment, the amplitude modulation module includes an operational amplifier and a resistor network; and the amplification factor of the operational amplifier is adjusted based on the resistor network.

[0008] In an optional embodiment, the phase compensation module includes a compensation capacitor and a DC removal capacitor; phase compensation is achieved based on the compensation capacitor, and DC component removal is achieved based on the DC removal capacitor; the compensation capacitor is connected in parallel to the signal transmission path to correct the phase offset of the industrial frequency fundamental wave; the DC removal capacitor is connected in series to the signal transmission path to block the DC component; the compensation capacitor is physically separated from the DC removal capacitor and functionally decoupled.

[0009] In an optional embodiment, the single-ended to differential output module adopts a dual operational amplifier architecture; wherein, the third operational amplifier outputs a positive-phase differential signal; the fourth operational amplifier outputs a negative-phase differential signal; the positive-phase differential signal and the negative-phase differential signal have equal amplitudes and opposite phases.

[0010] In an optional embodiment, the conversion module includes a differential constant current source circuit; the differential constant current source circuit is composed of two groups of symmetrical operational amplifier units; each group of operational amplifier units is respectively connected to an independent negative feedback network and a positive feedback network; the reference output current is set based on the negative feedback network; and the output stage voltage drop loss is offset based on the positive feedback network.

[0011] In an optional embodiment, the first series resistor group constitutes a negative feedback path of the first operational amplifier unit; the second series resistor group constitutes a negative feedback path of the second operational amplifier unit; and the resistance values ​​of the first series resistor group and the second series resistor group match each other.

[0012] In an optional embodiment, the signal processing circuit includes a two-stage AC coupling structure connected in series: The first-stage AC coupling structure is located at the output end of the integral amplifier module and is implemented by the first DC component removal module; The second-stage AC coupling structure is located at the DC-removing capacitor in the signal conditioning module and is implemented by the DC-removing capacitor; At least one DC coupling amplifier stage is provided between the first-stage AC coupling structure and the second-stage AC coupling structure.

[0013] The present application also provides a current measurement system, comprising: A Rogowski coil current transformer as described in any one of the above items; The data acquisition device has a differential current input port directly connected to the differential constant current signal output terminal.

[0014] Due to the adoption of the above technical solution, the present application has at least one of the following beneficial effects compared with the prior art:

[0015] 1. Through the integral amplification module and the phase compensation module, the differential signal is accurately converted into a current signal, making the current measurement result more accurate.

[0016] 2. The resistor in the compensation loop is used to suppress the DC saturation of the integrator, while the capacitor is used for phase compensation to ensure stability during signal processing.

[0017] 3. The use of differential signal transmission instead of traditional single-ended signal transmission enhances the system's resistance to external electromagnetic interference and makes the measurement results more stable and reliable.

[0018] 4. The data acquisition device can be directly connected to the differential constant current signal output port without the need for additional complex conversion devices, simplifying the overall architecture of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without inventive efforts. Among them: Figure 1 A schematic diagram of a framework of a Rogowski coil current transformer provided in one embodiment of the present application; Figure 2 for Figure 1 Schematic diagram of the signal processing circuit in the figure; Figure 3 A circuit diagram of an integral amplifier module provided in one embodiment of the present application; Figure 4 A circuit diagram of a signal conditioning module provided in one embodiment of the present application; Figure 5 A circuit diagram of a single-ended to differential output module provided in one embodiment of the present application; Figure 6 A circuit diagram of a conversion module provided in one embodiment of the present application; Figure 7 A schematic diagram of the framework of a current measurement system provided in one embodiment of the present application. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. It will be understood that the specific embodiments described herein are only used to explain the present application, rather than to limit the present application. It should also be noted that, for ease of description, only some, rather than all, structures related to the present application are shown in the drawings. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0021] The terms "first," "second," and the like in this application are used to distinguish between different objects, not to describe a particular order. Furthermore, the terms "including," "having," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or elements is not limited to the listed steps or elements, but may optionally include steps or elements not listed, or may optionally include other steps or elements inherent to the process, method, product, or apparatus.

[0022] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0023] Conventional current transformers in the prior art often exhibit drawbacks such as insufficient accuracy, susceptibility to signal saturation, weak anti-interference capabilities, and high system complexity when faced with high-precision, wide-band response, and complex electromagnetic environments. For example, conventional current transformers are difficult to accurately process high-frequency signals, and measurement results are easily distorted in strong electromagnetic interference environments. In view of this, the Rogowski coil current transformer proposed in this application makes current measurement results more accurate through integral amplification, phase compensation, differential signal output, and suppression of signal saturation. Figure 1 — Figure 2 As shown, Figure 1 This is a schematic diagram of the framework of a Rogowski coil current transformer provided in one embodiment of the present application. Figure 2 for Figure 1 The framework diagram of the signal processing circuit in the figure shows that the Rogowski coil current transformer includes a Rogowski coil and a signal processing circuit, which is connected to the Rogowski coil. The signal processing circuit converts the differential signal output by the Rogowski coil into a differential constant current signal output.

[0024] The Rogowski coil itself outputs a differential signal, which will result in large errors when used directly for current measurement. Through modules such as the integral amplifier module and phase compensation module in the signal processing circuit, the differential signal can be accurately converted into a corresponding current signal, thereby significantly improving the measurement accuracy.

[0025] The signal processing circuit includes an integral amplification module, a first DC component removal module, a signal adjustment module, a single-ended to differential output module and a conversion module.

[0026] The integral amplifier module is connected to the Rogowski coil to receive the differential signal and integrates and amplifies the differential signal based on the integral amplifier module. The Rogowski coil directly outputs the current change rate (i.e., the differential signal), while the actual current measurement requires the current value itself. Through the integral amplifier module, this differential signal can be converted into the corresponding original current signal, thereby achieving accurate current measurement.

[0027] Integral amplification can not only restore the original signal, but also adjust the amplification factor as needed to ensure a sufficient signal-to-noise ratio even under low current conditions, thereby improving measurement accuracy.

[0028] The first DC removal module removes the DC component from the integrated and amplified voltage signal. The presence of DC can mask or distort the true characteristics of AC signals, especially when accurately measuring small-amplitude AC signals. By removing the DC component, only the AC component related to current changes remains, improving the accuracy and reliability of current measurement.

[0029] Subsequent processing circuits have certain limitations on the dynamic range of the input signal. If the signal contains a large DC offset, the processing circuit will enter a saturated state, affecting its normal operation. Removing the DC component can prevent this saturation phenomenon and ensure the linearity and stability of the signal processing chain.

[0030] The signal conditioning module is connected to the first DC component removal module. The signal conditioning module includes an amplitude modulation module and a phase compensation module. The amplitude modulation module implements in-phase amplitude amplification. By adjusting the amplification factor, the system can flexibly adapt to different current measurement ranges and accuracy requirements. For example, a higher amplification factor can be selected for applications requiring high sensitivity, while a lower amplification factor can be used to avoid saturation when processing high currents.

[0031] Amplitude in-phase amplification means that all frequency components of the input signal are amplified uniformly without introducing additional phase shift or distortion, maintaining the integrity of the original signal.

[0032] The phase compensation module applies phase compensation to the signal after amplitude in-phase amplification. Phase compensation helps eliminate phase lag in the feedback loop that can cause system instability. Especially at high frequencies, proper phase compensation can prevent system oscillations and improve system stability and response speed.

[0033] The single-ended-to-differential output module is connected to the signal conditioning module. A symmetrical differential voltage signal is generated based on the single-ended-to-differential output module. The differential signal transmission method can effectively resist external electromagnetic interference (EMI). Because differential signals are transmitted in pairs and their polarity is opposite, externally introduced common-mode noise will be canceled out. Differential signal transmission can not only suppress common-mode noise, but also improve the signal-to-noise ratio by increasing the effective signal amplitude at the receiving end.

[0034] Based on the conversion module, the symmetrical differential voltage signal is converted into a differential constant current signal output; converting the voltage signal into a current signal can provide more stable transmission characteristics, especially in long-distance transmission; the current signal is not easily affected by changes in line resistance, so it can maintain high accuracy.

[0035] In summary, the Rogowski coil current transformer of this embodiment includes a Rogowski coil and a signal processing circuit; the signal processing circuit converts the differential signal into a differential constant current signal output; the signal processing circuit includes: an integral amplifier module, which integrates and amplifies the differential signal based on the integral amplifier module; a first DC component removal module, which removes the DC component from the voltage signal after the integral amplification based on the first DC component removal module; a signal conditioning module, which implements amplitude in-phase amplification and phase compensation; a single-ended to differential output module, which generates a symmetrical differential voltage signal based on the single-ended to differential output module; and a conversion module, which converts the symmetrical differential voltage signal into a differential constant current signal output based on the conversion module. Through the integral amplifier module and the phase compensation module, the differential signal is accurately converted into a current signal, making the current measurement result more accurate.

[0036] The integral amplifier module includes an integral amplifier circuit and a compensation circuit; integral amplification is realized based on the integral amplifier circuit; phase compensation and signal saturation suppression are realized based on the compensation circuit.

[0037] like Figure 3 As shown, Figure 3 This is a circuit diagram of an integral amplifier module provided in one embodiment of the present application. The differential signal output by the Rogowski coil is grounded through a first voltage regulator diode D1 to protect the circuit from overvoltage. The differential signal output by the Rogowski coil is grounded through a first resistor R1, which is a current-limiting resistor.

[0038] The differential signal output by the Rogowski coil is connected to the negative input terminal of the first operational amplifier U1 through the second resistor R2 and the third resistor R3; the positive input terminal of the first operational amplifier U1 is grounded; the output terminal of the first operational amplifier U1 is connected to the first DC component removal module; the positive power supply terminal of the first operational amplifier U1 is connected to the +5V power supply and grounded through the third capacitor C3; the negative power supply terminal of the first operational amplifier U1 is connected to the -5V power supply and grounded through the fourth capacitor C4.

[0039] One end of the first capacitor C1 is connected to the output end of the first operational amplifier U1; the other end of the first capacitor C1 is connected to the side of the third resistor R3 close to the first operational amplifier U1; the fourth resistor R4 and the fifth resistor R5 are connected in series to form a resistor group, and the resistor group is connected in parallel with the first capacitor C1; one end of the second capacitor C2 is grounded, and the other end of the second capacitor C2 is connected to the side of the fifth resistor R5 close to the fourth resistor R4; the sixth resistor R6 is connected in parallel with the second capacitor C2.

[0040] The second resistor R2, the third resistor R3, the first capacitor C1 and the first operational amplifier U1 constitute an integral amplification circuit; in this embodiment, the integral amplification factor is 12 times. In other embodiments, the integral amplification factor is adjusted by adjusting the resistance value of the second resistor R2 and / or the third resistor R3 and / or the capacitance value of the first capacitor C1, and no limitation is made to this.

[0041] The compensation loop includes a resistor and a capacitor connected in parallel; the resistor is used to suppress DC saturation of the integrator, and the capacitor is used for phase compensation; in this embodiment, the compensation loop is composed of a fourth resistor R4, a fifth resistor R5, a sixth resistor R6 and a second capacitor C2; the phase of the signal is compensated and signal saturation is suppressed based on the compensation loop.

[0042] The integrating amplifier module is connected to the first DC component removal module, which includes a fifth capacitor C5 and a seventh resistor R7; one end of the fifth capacitor C5 is connected to the output end of the first operational amplifier U1, and the other end of the fifth capacitor C5 is connected to the signal conditioning module; one end of the seventh resistor R7 is connected to the side of the fifth capacitor C5 away from the first operational amplifier U1; the other end of the seventh resistor R7 is grounded.

[0043] The fifth capacitor C5 is a coupling capacitor that blocks the DC component and allows only the AC signal to pass into the subsequent circuit; the seventh resistor R7 provides a load path to the ground for the fifth capacitor C5, ensuring that any residual DC component can be directed to the ground through this path instead of entering the subsequent circuit.

[0044] The amplitude modulation module includes an operational amplifier and a resistor network; the amplification factor of the operational amplifier is adjusted based on the resistor network.

[0045] like Figure 4 As shown, Figure 4This is a circuit diagram of a signal conditioning module provided in an embodiment of the present application, wherein the output signal of the first DC component removal module is connected to the positive input terminal of the second op amp U2; the negative input terminal of the second op amp U2 is grounded through the eighth resistor R8 and the ninth resistor R9; the negative input terminal of the second op amp U2 is connected to the output terminal of the second op amp U2 through the sixth capacitor C6; the negative input terminal of the second op amp U2 is connected to the first sliding rheostat RP1 and one end of the eleventh resistor R11 through the tenth resistor R10; the other end of the first sliding rheostat RP1 is connected to the output terminal of the second op amp U2; and the other end of the eleventh resistor R11 is connected to the output terminal of the second op amp U2.

[0046] The resistor network includes an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, and a first sliding rheostat RP1. The eighth and ninth resistors R8 and R9 are used to set the reference voltage or bias point of the second op amp U2, ensuring that it operates within a suitable range. The tenth and eleventh resistors R10 and R11, along with the first sliding rheostat RP1, form the feedback network for the second op amp U2, determining its gain. Adjusting the slider position of the first sliding rheostat RP1 changes the feedback resistor value, thereby adjusting the gain of the second op amp U2.

[0047] The phase compensation module includes a compensation capacitor and a DC removal capacitor; phase compensation is achieved based on the compensation capacitor, and DC removal is achieved based on the DC removal capacitor; the compensation capacitor is connected in parallel with the signal transmission path to correct the phase offset of the power frequency fundamental wave; the DC removal capacitor is connected in series with the signal transmission path to block the DC component; the compensation capacitor and the DC removal capacitor are physically separated and functionally decoupled.

[0048] The output end of the second operational amplifier U2 is grounded through the twelfth resistor R12; the output end of the second operational amplifier U2 is connected to one end of the thirteenth resistor R13 through the DC removal capacitor C5-01; the other end of the thirteenth resistor R13 is connected to the single-ended to differential output module; the other end of the thirteenth resistor R13 is grounded through the seventh capacitor C7; the seventh capacitor C7 is a compensation capacitor.

[0049] The DC-blocking capacitor C5-01 is connected in series in the signal transmission path, allowing AC signals to pass while blocking any DC components. This ensures that the signal entering the single-ended-to-differential output module contains no DC components, thus preventing it from affecting subsequent circuits.

[0050] The seventh capacitor, C7, is connected in parallel with the signal transmission path to correct phase shift. In power systems, the phase relationship between current and voltage is crucial for calculating parameters such as power factor. By adjusting its capacitance, C7 compensates for phase shift caused by circuit delays or other factors, ensuring the phase accuracy of the output signal.

[0051] like Figure 5 As shown, Figure 5 This is a circuit diagram of a single-ended to differential output module provided in one embodiment of the present application; the single-ended to differential output module adopts a dual operational amplifier architecture; wherein, the third operational amplifier U3 outputs a positive-phase differential signal; the fourth operational amplifier U4 outputs an inverting-phase differential signal; the positive-phase differential signal and the inverting-phase differential signal are equal in amplitude and opposite in phase; the positive terminal of the fourth operational amplifier U4 is grounded, forming the basic configuration of an inverting amplifier, and the working principle is the same as that of the first operational amplifier U1, which will not be repeated here.

[0052] The positive terminal of the third operational amplifier U3 receives the signal output by the signal adjustment module; the output terminal of the third operational amplifier U3 is connected to the conversion module; the negative terminal of the third operational amplifier U3 is connected to the negative terminal of the fourth operational amplifier U4; the output terminal of the fourth operational amplifier U4 is connected to the conversion module.

[0053] The positive end differential signal and the negative end differential signal are both passed through an RC network before being input into the conversion module to achieve phase compensation and remove DC components, which will not be described in detail here.

[0054] like Figure 6 As shown, Figure 6 This is a circuit diagram of a conversion module provided in one embodiment of the present application, wherein the conversion module includes a differential constant current source circuit; the differential constant current source circuit is composed of two groups of symmetrical operational amplifier units; each group of operational amplifier units is connected to an independent negative feedback network and a positive feedback network; a reference output current is set based on the negative feedback network; and the output stage voltage drop loss is offset based on the positive feedback network.

[0055] The first series resistor group constitutes a negative feedback path of the first operational amplifier unit; the second series resistor group constitutes a negative feedback path of the second operational amplifier unit; and the resistance values ​​of the first series resistor group and the second series resistor group match each other.

[0056] In this embodiment, the fourteenth resistor R14 and the fifteenth resistor R15 constitute a negative feedback path of the sixth operational amplifier U6; the sixteenth resistor R16 and the seventeenth resistor R17 constitute a negative feedback path of the fifth operational amplifier U5; and R14=R16, R15=R17, the reference values ​​of the two output currents are the same, ensuring current matching.

[0057] The eighteenth resistor R18 and the nineteenth resistor R19 constitute a positive feedback path of the sixth operational amplifier U6; the twentieth resistor R20 and the twenty-first resistor R21 constitute a positive feedback path of the fifth operational amplifier U5; the positive feedback network can help compensate for the current deviation caused by the output voltage change and ensure the stability of the output current.

[0058] The signal processing circuit consists of two stages of AC coupling structure connected in series: The first-stage AC coupling structure is located at the output end of the integral amplifier module and is implemented by the first DC component removal module; the first-stage AC coupling structure effectively removes the DC component in the voltage signal after integral amplification, ensuring that only the AC signal enters the subsequent processing stage.

[0059] The second-stage AC coupling structure is located at the DC-removing capacitor in the signal conditioning module and is implemented by the DC-removing capacitor; the second-stage AC coupling structure further removes the DC offset that may be introduced in the signal conditioning module, ensuring that the final output signal does not contain a DC component.

[0060] At least one DC coupling amplifier stage is provided between the first-stage AC coupling structure and the second-stage AC coupling structure; and a DC coupling amplifier stage is provided between the first-stage and second-stage AC coupling structures, which helps to stabilize the DC operating point of the entire system.

[0061] The present application also provides a current measurement system, such as Figure 7 As shown, Figure 7 A schematic diagram of a current measurement system according to an embodiment of the present application includes: A Rogowski coil current transformer as in any of the above items; The data acquisition device has a differential current input port directly connected to the differential constant current signal output end of the Rogowski coil current transformer.

[0062] In the several embodiments provided in this application, it should be understood that the disclosed methods and devices can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the modules or units is merely a logical functional division. In actual implementation, other division methods may be used, such as combining or integrating multiple units or components into another system, or ignoring or not implementing certain features.

[0063] The units described as separate components may or may not be physically separate, and 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 may be selected according to actual needs to achieve the purpose of this embodiment.

[0064] In addition, each functional unit in each embodiment of the present application may be integrated into a processing unit, each unit may exist physically separately, or two or more units may be integrated into a single unit. The above-mentioned integrated units may be implemented in the form of hardware or software functional units.

[0065] The above description is only an implementation method of the present application and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the description and drawings of this application, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A Rogowski coil current transformer, characterized in that: The device comprises a Rogowski coil and a signal processing circuit, wherein the signal processing circuit is connected to the Rogowski coil; based on the signal processing circuit, the differential signal output by the Rogowski coil is converted into a differential constant current signal output; the signal processing circuit comprises: an integral amplification module, performing integral amplification on the differential signal based on the integral amplification module; a first DC component removal module, which removes the DC component from the voltage signal after integration and amplification based on the first DC component removal module; A signal conditioning module connected to the first DC component removal module; the signal conditioning module includes an amplitude modulation module and a phase compensation module; the amplitude modulation module implements amplitude in-phase amplification; the phase compensation module performs phase compensation on the signal after the amplitude in-phase amplification; A single-ended to differential output module, the single-ended to differential output module is connected to the signal conditioning module; a symmetrical differential voltage signal is generated based on the single-ended to differential output module; The conversion module converts the symmetrical differential voltage signal into a differential constant current signal for output.

2. The Rogowski coil current transformer according to claim 1, characterized in that: The integral amplification module includes an integral amplification loop and a compensation loop; integral amplification is achieved based on the integral amplification loop; phase compensation and signal saturation suppression are achieved based on the compensation loop.

3. The Rogowski coil current transformer according to claim 2, characterized in that: The compensation loop includes a resistor and a capacitor connected in parallel; the resistor is used to suppress direct current saturation of the integrator, and the capacitor is used for phase compensation.

4. The Rogowski coil current transformer according to claim 1, characterized in that: The amplitude modulation module includes an operational amplifier and a resistor network; and the amplification factor of the operational amplifier is adjusted based on the resistor network.

5. The Rogowski coil current transformer according to claim 4, characterized in that: The phase compensation module includes a compensation capacitor and a DC removal capacitor; phase compensation is achieved based on the compensation capacitor, and DC component removal is achieved based on the DC removal capacitor; the compensation capacitor is connected in parallel to the signal transmission path to correct the phase offset of the power frequency fundamental wave; the DC removal capacitor is connected in series to the signal transmission path to block the DC component; the compensation capacitor is physically separated from the DC removal capacitor and functionally decoupled.

6. The Rogowski coil current transformer according to claim 1, characterized in that: The single-ended to differential output module adopts a dual operational amplifier architecture; wherein the third operational amplifier outputs a positive-phase differential signal; the fourth operational amplifier outputs a negative-phase differential signal; the positive-phase differential signal and the negative-phase differential signal have equal amplitudes and opposite phases.

7. The Rogowski coil current transformer according to claim 1, characterized in that: The conversion module includes a differential constant current source circuit; the differential constant current source circuit is composed of two groups of symmetrical operational amplifier units; each group of operational amplifier units is connected to an independent negative feedback network and a positive feedback network; a reference output current is set based on the negative feedback network; and the output stage voltage drop loss is offset based on the positive feedback network.

8. The Rogowski coil current transformer according to claim 7, characterized in that: The first series resistor group constitutes a negative feedback path of the first operational amplifier unit; the second series resistor group constitutes a negative feedback path of the second operational amplifier unit; and the resistance values ​​of the first series resistor group and the second series resistor group match each other.

9. The Rogowski coil current transformer according to claim 1, characterized in that: The signal processing circuit comprises a two-stage AC coupling structure in series: The first-stage AC coupling structure is located at the output end of the integral amplifier module and is implemented by the first DC component removal module; The second-stage AC coupling structure is located at the DC-removing capacitor in the signal conditioning module and is implemented by the DC-removing capacitor; At least one DC coupling amplifier stage is provided between the first-stage AC coupling structure and the second-stage AC coupling structure.

10. A current measurement system, characterized in that: include: The Rogowski coil current transformer according to any one of claims 1 to 9; The data acquisition device has a differential current input port directly connected to the differential constant current signal output terminal.

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