Electronic circuit for a rogowski coil

Abstract

The application relates to an electronic circuit applied to a Rogowski coil. The electronic circuit applied to the Rogowski coil comprises a voltage reduction circuit, a charge pump circuit and a signal processing circuit; through the voltage reduction circuit and the charge pump circuit, symmetrical double power supplies, namely a positive power supply voltage and a negative power supply voltage, can be provided for an operational amplifier of the signal processing circuit, so that the signal processing circuit works in a zero bias state. The voltage reduction circuit and the charge pump circuit also have a filtering effect, can filter out high-frequency noise and low-frequency noise of an external power supply, and thus improve the precision of current detection of the electronic circuit applied to the Rogowski coil. Further, compared with a traditional Rogowski coil signal processing circuit, the electronic circuit applied to the Rogowski coil no longer needs to be additionally connected with a negative voltage power supply, and the integration degree of the voltage reduction circuit and the charge pump circuit is high, so that the voltage reduction circuit and the charge pump circuit can be arranged on a chip with compact space, and small-size design is realized.

Description

Technical Field

[0001] This application relates to the field of Rogowski coil signal processing circuit technology, and in particular to an electronic circuit applied to Rogowski coils. Background Technology

[0002] A Rogowski coil is an alternating current sensor, a hollow ring-shaped coil available in both flexible and rigid forms. It can be directly wrapped around the conductor being measured to measure alternating current. Existing Rogowski coil signal processing circuits require an additional negative voltage power supply, which occupies a large area, hindering miniaturization. Utility Model Content

[0003] Therefore, it is necessary to provide an electronic circuit for Rogowski coils that does not require an additional negative voltage power supply, including:

[0004] A step-down circuit is used to connect an external power supply to its input terminal. The step-down circuit reduces the voltage of the external power supply to output a positive supply voltage.

[0005] The charge pump circuit has its input connected to the output of the buck converter; the charge pump circuit is used to reverse the positive supply voltage to output a negative supply voltage.

[0006] The signal processing circuit has an input terminal connected to the output terminal of the Rogowski coil, multiple first power supply terminals connected to the output terminal of the step-down circuit, and multiple second power supply terminals connected to the output terminal of the charge pump circuit. The signal processing circuit is used to amplify the output signal of the Rogowski coil.

[0007] In one specific embodiment, the above-mentioned step-down circuit includes:

[0008] The first filter circuit has its input terminal connected to an external power supply.

[0009] A linear regulator, the input of which is connected to the output of the first filter circuit, is used to reduce the voltage of the external power supply so as to output a positive supply voltage.

[0010] The second filter circuit has its input terminals connected to the output terminals of the linear regulator and its output terminals connected to the input terminals of the charge pump circuit and multiple first power supply terminals of the signal processing circuit.

[0011] In one specific embodiment, the first filter circuit includes: a first capacitor and a second capacitor connected in parallel to the input terminal of the linear regulator; wherein the first capacitor is a microfarad-level capacitor and the second capacitor is a picofarad-level capacitor.

[0012] In one specific embodiment, the first filter circuit further includes:

[0013] The first ferrite bead has its first end connected to an external power supply, and its second end connected to the input of a linear regulator.

[0014] In one specific embodiment, the second filter circuit includes a third capacitor, a fourth capacitor, and a fifth capacitor connected in parallel to the output of the linear regulator; wherein the third capacitor is a picofarad-level capacitor, the fourth capacitor is a nanofarad-level capacitor, and the fifth capacitor is a microfarad-level capacitor.

[0015] In one specific embodiment, the second filter circuit further includes:

[0016] The second ferrite bead is connected between the fourth and fifth capacitors.

[0017] In one specific embodiment, the charge pump circuit described above includes:

[0018] A charge pump, the input of which is connected to the output of a step-down circuit;

[0019] A flying capacitor is connected in series between the positive and negative terminals of the flying capacitor in the charge pump so that the charge pump can reverse the positive supply voltage to output a negative supply voltage.

[0020] The third filter circuit has its input connected to the output of the charge pump, and its output connected to multiple second power supply terminals of the signal processing circuit.

[0021] In one specific embodiment, the electronic circuit applied to the Rogowski coil further includes:

[0022] The sampling resistor has its first end connected to both the output of the Rogowski coil and the input of the signal processing circuit, while its second end is grounded.

[0023] In one specific embodiment, the signal processing circuit described above includes:

[0024] The integration module has an input terminal connected to the output terminal of the Rogowski coil, a first power supply terminal connected to the output terminal of the step-down circuit, and a second power supply terminal connected to the output terminal of the charge pump circuit.

[0025] DC blocking module; the input of the DC blocking module is connected to the output of the integration module.

[0026] The proportional amplifier module has its input terminal connected to the output terminal of the DC blocking module, its first power supply terminal connected to the output terminal of the step-down circuit, its second power supply terminal connected to the output terminal of the charge pump circuit, and its output terminal used to output the amplified signal.

[0027] In one specific embodiment, the signal processing circuit further includes:

[0028] The fourth filter circuit has its input terminal connected to the output terminal of the Rogowski coil, and its output terminal connected to the input terminal of the integration module.

[0029] The aforementioned electronic circuit applied to the Rogowski coil provides symmetrical dual power supplies—a positive and a negative supply voltage—to the operational amplifiers of the signal processing circuit through a buck converter and a charge pump circuit, enabling the signal processing circuit to operate in a zero-bias state. The buck converter and charge pump circuit also have filtering capabilities, removing high-frequency and low-frequency noise from the external power supply, thereby improving the accuracy of current detection in the electronic circuit applied to the Rogowski coil. Furthermore, compared to traditional Rogowski coil signal processing circuits, the aforementioned electronic circuit applied to the Rogowski coil no longer requires an additional negative power supply, and the high integration of the buck converter and charge pump circuit allows for placement on a compact chip, achieving miniaturized design. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology 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.

[0031] Figure 1 This is a block diagram of an electronic circuit applied to a Rogowski coil according to one embodiment;

[0032] Figure 2 An electronic circuit diagram of a step-down circuit applied in an electronic circuit of a Rogowski coil, according to one embodiment;

[0033] Figure 3 An electronic circuit diagram of a charge pump circuit applied in an electronic circuit of a Rogowski coil, according to one embodiment;

[0034] Figure 4 This is an electronic circuit diagram of a signal processing circuit applied to an electronic circuit of a Rogowski coil, as shown in one embodiment. Detailed Implementation

[0035] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0037] It is understood that the terms "first," "second," etc., used in this application may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another. For example, without departing from the scope of this application, a first filter circuit may be referred to as a second filter circuit, and similarly, a second filter circuit may be referred to as a first filter circuit. Both the first filter circuit and the second filter circuit are filter circuits, but they are not the same filter circuit.

[0038] It is understood that the term "connection" in the following embodiments should be understood as "electrical connection," "communication connection," etc., if the connected circuits, modules, units, etc., have electrical signal or data transmission with each other.

[0039] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising,” “including,” or “having,” etc., specify the presence of the stated feature, whole, step, operation, component, part, or combination thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof.

[0040] In traditional technology, current transformers are commonly used to detect current. However, current transformers contain magnetic materials, exhibit phase differences, have a limited applicable current range, and are prone to saturation under high currents. In contrast, Rogowski coils, which contain no iron core and have no hysteresis effect, are more advantageous for current detection. Furthermore, using Rogowski coils for current detection results in almost zero phase error after integration, no magnetic saturation, a wide current detection range from tens to thousands of amperes, and a wide response bandwidth. Rogowski coils have a simple structure and no direct circuit connection with the measured current, offering advantages such as wide measurement range, high accuracy, wide response bandwidth, small size, light weight, and stable reliability.

[0041] In a specific embodiment, such as Figure 1As shown, an electronic circuit 10 for use with Rogowski coils is provided, including: a step-down circuit 102, a charge pump circuit 104, and a signal processing circuit 106.

[0042] The input terminal of the step-down circuit 102 is used to connect to an external power supply; the step-down circuit 102 is used to reduce the voltage of the external power supply to output a positive supply voltage.

[0043] The input terminal of the charge pump circuit 104 is connected to the output terminal of the step-down circuit 102; the charge pump circuit 104 is used to reverse the positive supply voltage to output a negative supply voltage.

[0044] The input terminal of the signal processing circuit 106 is used to connect to the output terminal of the Rogowski coil 20. The multiple first power supply terminals of the signal processing circuit 106 are respectively connected to the output terminal of the step-down circuit 102, and the multiple second power supply terminals of the signal processing circuit 106 are respectively connected to the output terminal of the charge pump circuit 104. The signal processing circuit 106 is used to amplify the output signal of the Rogowski coil 20.

[0045] For example, the multiple first power supply terminals of the signal processing circuit 106 can be integrated into a single power port, allowing the buck converter 102 to power the signal processing circuit 106 through a power output terminal and this power port. Similarly, the multiple second power supply terminals of the signal processing circuit 106 can also be integrated into a single power port, allowing the charge pump circuit 104 to power the signal processing circuit 106 through a power output terminal and this power port. Furthermore, the integrated power port reduces the circuit board area, thereby enabling a miniaturized design of the electronic circuit 10 applied to the Rogowski coil. This also correspondingly reduces wiring operations and simplifies the workflow when using the electronic circuit 10 applied to the Rogowski coil.

[0046] For example, the multiple first power supply terminals of the signal processing circuit 106 can be connected one-to-one to the output terminal of the buck circuit 102. The lack of integrated first power supply terminals offers greater flexibility; a failure in any one first power supply terminal will not affect the others, reducing maintenance costs. Similarly, the multiple second power supply terminals of the signal processing circuit 106 can be connected one-to-one to the output terminal of the charge pump circuit 104. The lack of integrated second power supply terminals also offers greater flexibility; a failure in any one second power supply terminal will not affect the others, reducing maintenance costs.

[0047] The external power supply can be a DC source, and the buck circuit 102 is used to reduce the voltage of the DC source to output a positive supply voltage that matches the signal processing circuit 106. Specifically, the external power supply voltage can be +5V, and the buck circuit 102 reduces the +5V voltage to a positive supply voltage of +2.5V.

[0048] The charge pump circuit 104 reverses the obtained positive supply voltage to output a negative supply voltage that corresponds to the positive supply voltage and matches the signal processing circuit 106. Specifically, when the buck circuit 102 outputs a +2.5V voltage, the charge pump circuit 104 inverts this +2.5V positive supply voltage to obtain a -2.5V negative supply voltage. Compared with other circuits that can provide negative voltage, the charge pump circuit 104 reverses the positive supply voltage output by the buck circuit 102 to obtain a corresponding, high-precision negative supply voltage, thereby ensuring that the signal processing circuit 106 can obtain a symmetrical dual power supply.

[0049] Therefore, the electronic circuit 10 applied to the Rogowski coil, through the step-down circuit 102 and the charge pump circuit 104, can provide symmetrical dual power supplies—a positive supply voltage and a negative supply voltage—to the operational amplifier of the signal processing circuit 106, thereby enabling the signal processing circuit 106 to operate in a zero-bias state. The step-down circuit 102 and the charge pump circuit 104 also have a filtering function, capable of filtering out high-frequency and low-frequency noise from the external power supply, thereby improving the accuracy of current detection by the electronic circuit 10 applied to the Rogowski coil. Furthermore, compared to the conventional Rogowski coil 20 signal processing circuit 106, the electronic circuit 10 applied to the Rogowski coil no longer requires an additional negative power supply. Moreover, the step-down circuit 102 and the charge pump circuit 104 have high integration and can be arranged on a compact chip, achieving miniaturized design.

[0050] In a specific embodiment, such as Figure 2 As shown, the step-down circuit 102 includes: a first filter circuit 1022, a linear regulator 1024, and a second filter circuit 1026.

[0051] The input terminal of the first filter circuit 1022 is used to connect to an external power supply.

[0052] The first filter circuit 1022 is used to filter the voltage of the external power supply. After filtering by the first filter voltage, the voltage ripple of the external power supply can be reduced, making the voltage more stable, so as to provide a stable voltage for the linear regulator 1024.

[0053] The input terminal of the linear regulator 1024 is connected to the output terminal of the first filter circuit 1022. The linear regulator 1024 is used to reduce the voltage of the external power supply to output a positive supply voltage.

[0054] For example, the linear regulator 1024 can be a linear low-dropout regulator of model AMS1117.25. This linear low-dropout regulator integrates overheat protection and current limiting circuitry. When the temperature of the thermal sensing point exceeds 165°C, the thermal protection circuit will shut down the regulator, preventing damage to the chip due to overheating or overcurrent, thereby improving the reliability of the electronic circuit 10 applied to the Rogowski coil.

[0055] The input terminal of the second filter circuit 1026 is connected to the output terminal of the linear regulator 1024, and the output terminal of the second filter circuit 1026 is connected to the input terminal of the charge pump circuit 104 and multiple first power supply terminals of the signal processing circuit 106.

[0056] The second filter circuit 1026 is used to filter the positive supply voltage output by the linear regulator 1024. After filtering by the second filter voltage, the ripple of the positive supply voltage output by the linear regulator 1024 can be reduced, making the positive supply voltage more stable, so as to provide a stable voltage for the charge pump circuit 104 and the signal processing circuit 106 and reduce noise.

[0057] In a specific embodiment, such as Figure 2 As shown, the first filter circuit 1022 includes: a first capacitor connected in parallel to the input terminal of the linear regulator 1024. Figure 2 C29 in the middle) and the second capacitor ( Figure 2 (C28 in the example), where the first capacitor is a microfarad-level capacitor and the second capacitor is a picofarad-level capacitor.

[0058] The first capacitor, at the microfarad level, can filter out low-frequency noise, and the second capacitor, at the picofarad level, can filter out high-frequency noise, thus enabling the first filter circuit 1022 to filter out both high-frequency and low-frequency noise simultaneously.

[0059] For example, the first capacitor can be a 10μF capacitor, and the second capacitor can be a 100pF capacitor.

[0060] In a specific embodiment, such as Figure 2 As shown, the first filter circuit 1022 further includes: a first ferrite bead ( Figure 2 L3 in the middle.

[0061] The first end of the first ferrite bead is used to connect to an external power supply, and the second end of the first ferrite bead is connected to the input terminal of the linear regulator 1024.

[0062] Compared to inductors, ferrite beads exhibit resistive behavior at high frequencies, effectively utilizing high-frequency noise and converting it into heat energy, thereby achieving complete elimination of high-frequency noise. Therefore, the first ferrite bead can further improve the filtering effect of high-frequency noise and enhance its filtering capacity.

[0063] Furthermore, compared to inductors, ferrite beads are smaller in size and more suitable for use in space-constrained circuit designs. Therefore, the application of the first ferrite bead facilitates the miniaturization of the electronic circuit 10 used in the Rogowski coil.

[0064] For example, the first ferrite bead may be a ferrite bead with an impedance of 100Ω at a frequency of 100MHz.

[0065] In a specific embodiment, such as Figure 2 As shown, the second filter circuit 1026 includes: a third capacitor connected in parallel to the output terminal of the linear regulator 1024. Figure 2 C25 in the middle), the fourth capacitor ( Figure 2 C26) and the fifth capacitor ( Figure 2 (C24 in the text), where the third capacitor is a picofarad-level capacitor, the fourth capacitor is a nanofarad-level capacitor, and the fifth capacitor is a microfarad-level capacitor.

[0066] Among them, the third capacitor at the picofarad level and the fourth capacitor at the nanofarad level can filter out high-frequency noise, and the fifth capacitor at the microfarad level can filter out low-frequency noise, so that the second filter circuit 1026 can filter out both high-frequency and low-frequency noise at the same time.

[0067] For example, the third capacitor can be a 10pF capacitor, the fourth capacitor can be a 100nF capacitor, and the fifth capacitor can be a 10μF capacitor.

[0068] In one specific embodiment, the second filter circuit 1026 further includes: a second ferrite bead ( Figure 2 L2 in the middle.

[0069] The second ferrite bead is connected between the fourth and fifth capacitors.

[0070] Similar to the first ferrite bead, the second ferrite bead can further improve the filtering effect of high-frequency noise and enhance the filtering function. Furthermore, the application of the second ferrite bead facilitates the miniaturization design of the electronic circuit 10 used in the Rogowski coil.

[0071] For example, the second ferrite bead can be a ferrite bead with an impedance of 100Ω at a frequency of 100MHz.

[0072] In a specific embodiment, such as Figure 3 As shown, the charge pump circuit 104 includes: a charge pump 1042, a flying capacitor ( Figure 3 (C27) and the third filter circuit 1044.

[0073] The input terminal of the charge pump 1042 is connected to the output terminal of the step-down circuit 102.

[0074] A flying capacitor is connected in series between the positive and negative terminals of the charge pump 1042 so that the charge pump 1042 can be used to reverse the positive supply voltage to output a negative supply voltage.

[0075] For example, the charge pump 1042 can be a charge pump 1042 DC-DC (Direct Current-Direct Current) converter of model SGM3207YN5G / TR.

[0076] The input terminal of the third filter circuit 1044 is connected to the output terminal of the charge pump 1042, and the output terminal of the third filter circuit 1044 is connected to multiple second power supply terminals of the signal processing circuit 106.

[0077] The third filter circuit 1044 is used to filter the negative supply voltage output by the charge pump 1042. After filtering by the third filter voltage, the ripple of the negative supply voltage output by the charge pump 1042 can be reduced, making the negative supply voltage more stable, so as to provide a stable negative supply voltage for the signal processing circuit 106 and reduce noise.

[0078] In a specific embodiment, such as Figure 3 As shown, the third filter circuit 1044 includes: a sixth capacitor connected in parallel to the output terminal of the charge pump 1042. Figure 3 C23 in the middle), the seventh capacitor ( Figure 3 C22) and the eighth capacitor ( Figure 3 C21 in the middle), and the inductor connected between the sixth and seventh capacitors ( Figure 3 In the L1 of the series, the sixth capacitor is a microfarad-level capacitor, the seventh capacitor is a picofarad-level capacitor, and the eighth capacitor is a nanofarad-level capacitor.

[0079] Among them, the sixth capacitor at the microfarad level can filter out low-frequency noise, and the seventh capacitor at the picofarad level and the eighth capacitor at the nanofarad level can filter out high-frequency noise, so that the third filter circuit 1044 can filter out both high-frequency and low-frequency noise at the same time.

[0080] For example, the sixth capacitor can be a 10μF capacitor, the fourth capacitor can be a 100pF capacitor, and the fifth capacitor can be a 100nF capacitor.

[0081] In one specific embodiment, the inductor connected between the sixth and seventh capacitors can be replaced with a ferrite bead. The ferrite bead can act as a filter, and its filtering effect is better than that of the inductor, thus enabling the miniaturization of the electronic circuit 10 applied to the Rogowski coil.

[0082] For example, when the device connected between the sixth and seventh capacitors is a ferrite bead, the ferrite bead can be selected as having an impedance of 100Ω at a frequency of 100MHz.

[0083] In a specific embodiment, such as Figure 4 As shown, the electronic circuit 10 applied to the Rogowski coil further includes: a sampling resistor ( Figure 4 (R1, R10, and R20 in the original text).

[0084] The first end of the sampling resistor is connected to the output end of the Rogowski coil 20 and the input end of the signal processing circuit 106, respectively, and the second end of the sampling resistor is grounded.

[0085] When the Rogowski coil 20 is not connected to the electronic circuit 10 applied to the Rogowski coil or the connected Rogowski coil 20 is damaged, the sampling resistor can pull the external input low to ground, thereby preventing the flow of incorrect signals and improving the reliability of the electronic circuit 10 applied to the Rogowski coil.

[0086] It should be noted that the electronic circuit 10 applied to the Rogowski coil can be used for single-phase current detection as well as three-phase current detection. For example, current detection can be performed using the aforementioned electronic circuit 10 applied to the Rogowski coil. The electronic current transformer is a three-phase product with a Rogowski coil 20 and an integrator. Specifically, as shown... Figure 4 Three-phase current detection can be achieved using a first, second, and third Rogowski coil. Each coil detects the current in the phase corresponding to the measured current, thus obtaining the induced voltage of that phase. Specifically, the first Rogowski coil detects the current in phase A; the IA+ port of sampling resistor R1 is connected to the positive port of the first Rogowski coil, and the IA- port is connected to the negative port. Similarly, the second Rogowski coil detects the current in phase B; the IB+ port of sampling resistor R10 is connected to the positive port of the second Rogowski coil, and the IB- port is connected to the negative port. Finally, the third Rogowski coil detects the current in phase C; the IC+ port of sampling resistor R20 is connected to the positive port of the third Rogowski coil, and the IC- port is connected to the negative port.

[0087] In a specific embodiment, such as Figure 4 As shown, the signal processing circuit 106 includes: an integration module 1062, a DC blocking module 1064, and a proportional amplification module 1066.

[0088] The input terminal of the integrator module 1062 is used to connect to the output terminal of the Rogowski coil 20. The first power supply terminal of the integrator module 1062 is connected to the output terminal of the step-down circuit 102, and the second power supply terminal of the integrator module 1062 is connected to the output terminal of the charge pump circuit 104.

[0089] The integrator module 1062 amplifies the input signal and lags the signal phase by 90 degrees. Since the Rogowski coil 20 leads the waveform of the measured signal by 90 degrees before outputting it, the integrator module 1062 can output a signal in phase with the measured current.

[0090] Specifically, the positive power supply terminal of operational amplifier U1A is connected to the output terminal of buck circuit 102, and the negative power supply terminal of operational amplifier U1A is connected to the output terminal of charge pump circuit 104. Capacitors C2 and C3 are used to filter the power supply terminal of operational amplifier U1A; for example, capacitors C2 and C3 can be 100nF capacitors. The capacitance value of capacitor C4 can be calculated based on the amplification ratio of the back-end output of integrator module 1062; generally, capacitor C4 is a capacitor in the pF to nF range; for example, capacitor C4 can be a 100nF capacitor. The resistor R4 connected in parallel with the feedback circuit (i.e., the branch where capacitor C4 is located) is used to limit the DC gain and suppress zero drift; generally, resistor R4 is a resistor in the hundreds of kilovolt range to the megavolt range; for example, resistor R4 can be a 20MΩ resistor.

[0091] Similarly, operational amplifiers U2A and U3A are set to correspond with operational amplifier U1A; capacitors C7 and C12 are set to correspond with capacitor C2; capacitors C8 and C13 are set to correspond with capacitor C3; capacitors C9 and C14 are set to correspond with capacitor C4; and resistors R13 and R23 are set to correspond with resistor R4. These details will not be elaborated further here.

[0092] The input terminal of the DC blocking module 1064 is connected to the output terminal of the integrator module 1062. The DC blocking module 1064 is used to filter out the DC component in the circuit.

[0093] Specifically, the capacitance C5 is determined by the frequency of the effective input signal, typically ranging from pF to nF; for example, capacitor C5 can be a 100nF capacitor. Resistor R5 provides a path for the DC signal; for example, resistor R5 can be a 1.27MΩ, 1.2MΩ, or 1.24MΩ resistor.

[0094] Similarly, capacitors C10 and C15 are set to correspond to capacitor C5, and resistors R14 and R24 are set to correspond to resistor R5, which will not be elaborated further here.

[0095] The input terminal of the proportional amplifier module 1066 is connected to the output terminal of the DC blocking module 1064, the first power supply terminal of the proportional amplifier module 1066 is connected to the output terminal of the step-down circuit 102, the second power supply terminal of the proportional amplifier module 1066 is connected to the output terminal of the charge pump circuit 104, and the output terminal of the proportional amplifier module 1066 is used to output the amplified output signal.

[0096] The proportional amplifier module 1066 is used to amplify the input signal proportionally.

[0097] Specifically, the positive power supply terminal of operational amplifier U1B is connected to the output terminal of buck circuit 102, and the negative power supply terminal of operational amplifier U1B is connected to the output terminal of charge pump circuit 104. The output terminal of operational amplifier U1B is used to output the amplified output signal. Resistors R01 and R04 are laser-cut resistors, which can be precisely adjusted to a suitable output value according to the external signal input (output voltage of Rogowski coil 20).

[0098] Similarly, operational amplifiers U2B and U3B are set to correspond to operational amplifier U1B, resistors R02 and R03 are set to correspond to resistor R01, and resistors R05 and R06 are set to correspond to resistor R04. These details will not be elaborated further here.

[0099] Furthermore, the positive power supply terminals of operational amplifiers U1B, U2B, and U3B can be integrated into a single main positive power supply terminal. With this integrated port, the output of the buck converter 102 can be connected to this main positive power supply terminal to power operational amplifiers U1B, U2B, and U3B respectively, reducing wiring operations and decreasing the circuit board area of ​​the electronic circuit 10 used in the Rogowski coil. Alternatively, the positive power supply terminals of operational amplifiers U1B, U2B, and U3B can be connected one-to-one to the output of the buck converter 102. In this non-integrated port configuration, a failure at any positive power supply terminal will not affect the others, thus reducing maintenance costs. Similarly, the negative power supply terminals of operational amplifier U1B, operational amplifier U2B, and operational amplifier U3B can be integrated into a single negative power supply terminal, or they can be connected one-to-one to the output terminal of charge pump circuit 104.

[0100] Furthermore, the positive power supply terminals of the two operational amplifiers in any phase can be integrated into a single positive power supply terminal. For example, the positive power supply terminals of operational amplifier U1A and operational amplifier U1B in phase A can be integrated into a single positive power supply terminal; in this case, it is unnecessary to connect the positive power supply terminals of operational amplifier U1A and operational amplifier U1B separately, simplifying the wiring operation. Of course, the positive power supply terminals of the two operational amplifiers in any phase can also be connected one-to-one to the output terminals of the buck circuit 102. Similarly, the negative power supply terminals of the two operational amplifiers in any phase can also be integrated into a single negative power supply terminal, or connected one-to-one to the output terminals of the charge pump circuit 104.

[0101] In a specific embodiment, such as Figure 4 As shown, the signal processing circuit 106 further includes: a current-limiting resistor ( Figure 4 (R9, R17, and R29 in the text).

[0102] The current-limiting resistor serves as a current-limiting protection, providing the processed analog signal to the back-end processing circuit to improve the reliability of the electronic circuit 10 applied to the Rogowski coil.

[0103] In a specific embodiment, such as Figure 4 As shown, the signal processing circuit 106 also includes a fourth filter circuit 1068.

[0104] The input terminal of the fourth filter circuit 1068 is used to connect to the output terminal of the Rogowski coil 20, and the output terminal of the fourth filter circuit 1068 is connected to the input terminal of the integration module 1062.

[0105] The fourth filter circuit 1068 performs preliminary processing on the output signal of the Rogowski coil 20. With the rated input value of the effective signal (the output signal of the Rogowski coil 20) at 40mV and the frequency at 50Hz, capacitors of k-level and nF-level can be selected to process the output signal of the Rogowski coil 20, making the waveform of the input Rogowski coil 20 output signal smoother.

[0106] In the description of this specification, references to terms such as "some embodiments," "other embodiments," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative descriptions of the above terms do not necessarily refer to the same embodiments or examples.

[0107] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0108] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these modifications and improvements all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. An electronic circuit applied to Rogowski coils, characterized in that, include: A step-down circuit, wherein the input terminal of the step-down circuit is used to connect to an external power supply; the step-down circuit is used to reduce the voltage of the external power supply to output a positive supply voltage; A charge pump circuit, the input of which is connected to the output of the step-down circuit; the charge pump circuit is used to reverse the positive supply voltage to output a negative supply voltage. A signal processing circuit, wherein the input terminal of the signal processing circuit is used to connect to the output terminal of the Rogowski coil, the plurality of first power supply terminals of the signal processing circuit are respectively connected to the output terminal of the buck circuit, and the plurality of second power supply terminals of the signal processing circuit are respectively connected to the output terminal of the charge pump circuit; the signal processing circuit is used to amplify the output signal of the Rogowski coil.

2. The electronic circuit applied to a Rogowski coil according to claim 1, characterized in that, The step-down circuit includes: A first filter circuit, wherein the input terminal of the first filter circuit is used to connect to the external power supply; A linear regulator, the input of which is connected to the output of the first filter circuit, is used to reduce the voltage of the external power supply in order to output the positive supply voltage; The second filter circuit has its input terminal connected to the output terminal of the linear regulator, and its output terminal connected to the input terminal of the charge pump circuit and multiple first power supply terminals of the signal processing circuit.

3. The electronic circuit applied to a Rogowski coil according to claim 2, characterized in that, The first filter circuit includes: a first capacitor and a second capacitor connected in parallel to the input terminal of the linear regulator; wherein the first capacitor is a microfarad-level capacitor and the second capacitor is a picofarad-level capacitor.

4. The electronic circuit applied to a Rogowski coil according to claim 3, characterized in that, The first filter circuit further includes: The first magnetic bead has a first end connected to the external power supply and a second end connected to the input terminal of the linear regulator.

5. The electronic circuit applied to a Rogowski coil according to claim 2, characterized in that, The second filter circuit includes a third capacitor, a fourth capacitor, and a fifth capacitor connected in parallel to the output terminal of the linear regulator; wherein the third capacitor is a picofarad-level capacitor, the fourth capacitor is a nanofarad-level capacitor, and the fifth capacitor is a microfarad-level capacitor.

6. The electronic circuit applied to a Rogowski coil according to claim 5, characterized in that, The second filter circuit also includes: The second magnetic bead is connected between the fourth capacitor and the fifth capacitor.

7. The electronic circuit applied to a Rogowski coil according to claim 1, characterized in that, The charge pump circuit includes: A charge pump, the input of which is connected to the output of the step-down circuit; A flying capacitor is connected in series between the positive and negative terminals of the charge pump so that the charge pump can reverse the positive supply voltage to output the negative supply voltage. The third filter circuit has its input terminal connected to the output terminal of the charge pump, and its output terminal connected to multiple second power supply terminals of the signal processing circuit.

8. The electronic circuit applied to a Rogowski coil according to claim 1, characterized in that, Also includes: A sampling resistor, the first end of which is connected to the output terminal of the Rogowski coil and the input terminal of the signal processing circuit, and the second end of which is grounded.

9. The electronic circuit applied to a Rogowski coil according to claim 1, characterized in that, The signal processing circuit includes: An integrating module, wherein the input terminal of the integrating module is connected to the output terminal of the Rogowski coil, the first power supply terminal of the integrating module is connected to the output terminal of the buck circuit, and the second power supply terminal of the integrating module is connected to the output terminal of the charge pump circuit; A DC blocking module, wherein the input terminal of the DC blocking module is connected to the output terminal of the integration module; A proportional amplifier module is provided, wherein the input terminal of the proportional amplifier module is connected to the output terminal of the DC blocking module, the first power supply terminal of the proportional amplifier module is connected to the output terminal of the step-down circuit, the second power supply terminal of the proportional amplifier module is connected to the output terminal of the charge pump circuit, and the output terminal of the proportional amplifier module is used to output the amplified output signal.

10. The electronic circuit applied to a Rogowski coil according to claim 9, characterized in that, The signal processing circuit further includes: The fourth filter circuit has its input terminal connected to the output terminal of the Rogowski coil, and its output terminal connected to the input terminal of the integration module.

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