Ultra-wideband response performance expansion circuit of capacitive inductive voltage sensor and test method

Abstract

The invention discloses a capacitive inductive voltage sensor ultra-wideband response performance expansion circuit and a test method. According to the circuit, the ultra-wideband response capability is improved by cascading a hybrid integrating circuit, a high-pass filtering module and a voltage follower; the hybrid integrating circuit is formed by connecting a passive integrator (self-integrating to process low frequency and suppress high-frequency noise) and an active integrator (reducing high frequency in a differential mode) in series to cooperatively broaden the frequency band; the high-pass filter filters DC bias, and the voltage follower realizes impedance matching and signal isolation. Experiments prove that the hybrid voltage sensor can realize good waveform reduction on sinusoidal signals as low as 5Hz and steep waves as high as 10MHz, and the voltage division ratio is stable; for a 1kHz signal, after the circuit is inserted, the output phase is consistent with the input, the amplitude is accurately restored according to the designed voltage division ratio, the phase lead and the amplitude attenuation are effectively inhibited, the traditional frequency band limitation is broken through, and the circuit is suitable for an ultra-wideband voltage measurement scene.

Description

Technical Field

[0001] This application belongs to the field of power equipment technology, and specifically relates to an ultra-wideband response performance extension circuit and test method for a capacitive inductive voltage sensor. Background Technology

[0002] As a key non-contact measuring device in power systems, the bandwidth of capacitive voltage sensors directly determines their ability to capture dynamic voltage signals. With the rapid development of smart grids and new energy power generation technologies, the switching frequency of power electronic equipment has jumped from the traditional kHz level to the MHz level. Complex dynamic signals such as nanosecond-level transient overvoltages place stringent requirements on the ultra-wide bandwidth (several Hz to tens of MHz) of sensors.

[0003] Traditional capacitive voltage sensors typically have bandwidths limited to the 100kHz-1MHz range, which is insufficient to meet the monitoring requirements of new power equipment. Key bottlenecks include:

[0004] Parasitic parameters of the sensor itself limit its performance: the distributed capacitance of the sensor and the stray capacitance to ground constitute a low-pass characteristic, which leads to significant attenuation of high-frequency signals and makes it impossible to effectively capture transient voltages in the MHz range.

[0005] Performance limitations of signal conditioning circuits: Impedance transformation circuits based on traditional operational amplifiers are limited by the gain-bandwidth product, which can easily produce significant phase distortion in the MHz band, resulting in a decrease in signal restoration accuracy.

[0006] Transmission line effect interference: Transmission line effect between the sensor and the measurement system can introduce standing wave interference, especially when measuring over long distances, making it difficult to guarantee signal integrity.

[0007] Therefore, existing wideband extension solutions have significant limitations and cannot adequately address both high and low frequency responses.

[0008] 1. The one-sidedness of single structure optimization: For example, using a coplanar waveguide structure to reduce the distributed capacitance to the level of 0.1pF can achieve a bandwidth of 500MHz, but it does not optimize for low-frequency response, and low-frequency signals are easily affected by noise. Although distributed amplification technology combined with adaptive bias circuit can compensate for high-frequency gain drop, the structure is complex and costly, and the problems of DC drift and cumulative error in the low-frequency band are prominent.

[0009] 2. Lack of coordinated signal processing mechanisms: Traditional passive integrators are only suitable for initial integration in the low-frequency band and have weak high-frequency noise suppression capabilities; active integrators focus on high-frequency signal restoration, but lack low-frequency stability. Existing technologies have not achieved coordination between the two and lack effective DC bias filtering (such as high-pass filtering) and impedance matching (such as voltage followers) mechanisms, resulting in the inability to achieve ideal high-frequency and low-frequency responses simultaneously. Summary of the Invention

[0010] To achieve the above objectives, this application provides an ultra-wideband response performance extension circuit for a capacitive inductive voltage sensor. A hybrid integration circuit is inserted into the capacitive inductive voltage sensor to form a hybrid voltage sensor. The hybrid voltage sensor improves the low-frequency and high-frequency response capability of the induced voltage through the hybrid integration circuit.

[0011] The hybrid voltage sensor is composed of an integrating circuit module, a high-pass filter module, and a voltage follower cascaded together. The integrating circuit module is used to measure the voltage of the conductor being measured in differential mode. The differential signal is integrated and restored. The high-pass filter module is used to filter out the DC bias voltage introduced in the integration circuit module. The voltage follower is used to achieve output impedance matching and signal isolation, ensuring the integrity of the high-frequency signal and the stability of the low-frequency response.

[0012] In one embodiment, the integration circuit module is composed of a passive integrator and an active integrator connected in series. The passive integrator operates in self-integration mode to perform preliminary integration processing on low-frequency signals and suppress high-frequency noise interference. The active integrator operates in differentiation mode to perform integration and restoration on high-frequency signals. The active and passive integrators work together to broaden the measurement bandwidth and improve the consistency of the full-frequency response.

[0013] The active integrator is connected in series with the high-pass filter module.

[0014] In one embodiment, the passive integrator consists of a load resistor R. m It consists of coupling capacitor C1 and load capacitor C2;

[0015] Wherein, the input terminal of the coupling capacitor C1 is connected to the voltage of the conductor being measured. The positive terminal is connected to the positive terminal, and the output terminal is connected to the input terminal of the load resistor Rm. The output terminal of the load resistor Rm is connected to the voltage of the conductor being measured. The negative terminals are connected to form a closed loop. The load capacitor C2 is connected in parallel to the two ends of the load resistor Rm away from the active integrator, and the load capacitor C2 is grounded.

[0016] In one embodiment, the active integrator consists of an operational amplifier A1 and an input resistor. Feedback capacitor and feedback resistor ;

[0017] The non-inverting input of operational amplifier A1 is connected to the input of the load resistor Rm, and the inverting input is connected to the input resistor. A feedback resistor is connected in parallel between the inverting input and output of the operational amplifier A1 and the output terminal of the load resistor Rm. The feedback resistor With feedback capacitor Series connection.

[0018] In one embodiment, the high-pass filter consists of a resistor. and capacitor constitute;

[0019] Wherein, the capacitor The input terminal is connected in series with the output terminal of the operational amplifier A1, and the capacitor The output terminal and the resistor One end is connected to the resistor. The other end is connected to the load capacitor C2 and grounded; the resistor The voltage follower is connected in parallel at both ends on the side furthest from the active integrator.

[0020] In one embodiment, the voltage follower is composed of operational amplifiers A1 and A2, input resistor R2, and resistor R3;

[0021] The non-inverting input terminal of operational amplifiers A1 and A2 is connected in series with the input resistor R2 and then connected to the resistor via a transmission line. The input terminals of operational amplifiers A1 and A2 are connected together, and the output terminals and inverting input terminals are directly connected through resistor R3; and

[0022] An oscilloscope is connected in series between the output terminals of operational amplifiers A1 and A2 and the output terminal of load capacitor C2. The oscilloscope is used to display the output voltage. Waveform.

[0023] In one embodiment, a resistor R4 is connected in series between the output of the operational amplifiers A1 and A2 and the oscilloscope.

[0024] A test method for extending the ultra-wideband response performance of a capacitive inductive voltage sensor includes the following steps:

[0025] S1. Obtain the design parameters of the capacitive inductive voltage sensor and obtain the equivalent circuit diagram of the capacitive inductive voltage sensor without the insertion of the hybrid integration circuit;

[0026] S2. Using the equivalent circuit diagram, determine the influencing factors of the corner frequency of the capacitive induction voltage sensor measurement system, optimize the parameters of each capacitor and resistor in the hybrid integration circuit, and make the measurement loop in a self-integrating state over a wide frequency range.

[0027] S3. Insert the optimized hybrid integration circuit into the measurement circuit of the capacitive induction voltage sensor to obtain the hybrid voltage sensor;

[0028] S4. Perform a frequency response test on the hybrid voltage sensor. Use a signal generator to input voltage signals of different frequencies, record the output voltage waveform displayed on an oscilloscope, and verify the effectiveness of the hybrid voltage sensor in the low-frequency to high-frequency range.

[0029] In one embodiment, the equivalent circuit diagram includes a coupling capacitor C1, a load capacitor C2, and an input resistor R2;

[0030] The coupling capacitor C1 is connected in series with the input resistor R2, and the input terminal of the coupling capacitor C1 is connected to the voltage of the conductor being measured. The positive terminal of the input resistor R2 is connected to the positive terminal of the conductor being measured, and the output terminal of the input resistor R2 is connected to the voltage of the conductor being measured. The negative terminal of the input resistor R2 is connected to the load capacitor C2 in parallel on one side of the input resistor R2, which is close to the coupling capacitor C1. An oscilloscope is connected in parallel on the other side of the input resistor R2. The oscilloscope is used to acquire the output voltage waveform across the input resistor R2.

[0031] Compared with the prior art, the beneficial effects of this application are:

[0032] This invention effectively overcomes the bandwidth limitations of traditional capacitive voltage sensors by introducing a cascaded structure of a hybrid integrator circuit, a high-pass filter module, and a voltage follower into a capacitive inductive voltage sensor, achieving accurate voltage measurement over an ultra-wide frequency range. The hybrid integrator circuit consists of a passive integrator and an active integrator connected in series. The passive integrator operates in self-integration mode, performing preliminary integration processing on low-frequency signals and suppressing high-frequency noise interference. The active integrator performs integration and reconstruction of high-frequency signals in differential mode. The synergistic effect of both expands the measurement bandwidth and improves the consistency of the full-frequency response. The high-pass filter module filters out the DC bias voltage introduced by the integrator circuit module, avoiding the accumulation of measurement errors caused by DC drift. The voltage follower achieves output impedance matching and signal isolation, ensuring the integrity of high-frequency signal transmission and the stability of the low-frequency response.

[0033] The hybrid voltage sensor of this invention has been experimentally verified to achieve excellent waveform reproduction for sinusoidal voltage signals as low as 5Hz and steep-wave signals up to 10MHz, while maintaining a stable voltage division ratio. This solves the technical pain point of traditional sensors being unable to simultaneously meet the requirements of low-frequency and high-frequency responses. In practical applications, this circuit can effectively suppress signal phase distortion and amplitude attenuation. For example, when measuring a 1kHz sinusoidal signal, after inserting the hybrid integrator circuit, the output signal phase is consistent with the input, and the amplitude is accurately reproduced according to the designed voltage division ratio, significantly improving signal reproduction accuracy. Furthermore, the circuit structure is simple, and the cost is controllable after parameter optimization. It can meet the monitoring needs of nanosecond-level transient overvoltages and wide-band dynamic voltages in fields such as smart grids and new energy power generation, improving the safety and reliability of power system operation and possessing significant engineering application value. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 A measurement schematic diagram of an ultra-wideband response performance extension circuit for a capacitive inductive voltage sensor provided in this application;

[0036] Figure 2 A schematic diagram of an ultra-wideband response performance extension circuit for a capacitive inductive voltage sensor provided in this application;

[0037] Figure 3 The equivalent circuit diagram of the capacitive inductive voltage sensor provided in this application;

[0038] Figure 4 A schematic diagram of the amplitude-frequency characteristic curve of the capacitive inductive voltage sensor provided in this application;

[0039] Figure 5 A schematic diagram of the test method for extending the ultra-wideband response performance of a capacitive inductive voltage sensor provided in this application;

[0040] Figure 6 The results of the low-frequency response characteristics of the extended circuit for the ultra-wideband response performance of the capacitive inductive voltage sensor provided in this application;

[0041] Figure 7 The results of the high-frequency response characteristics of the ultra-wideband response performance extension circuit A of the capacitive inductive voltage sensor provided in this application;

[0042] Figure 8 The results of measuring a 1kHz sinusoidal signal are provided for the ultra-wideband response performance extension circuit of a capacitive inductive voltage sensor provided in this application.

[0043] Explanation of reference numerals in the attached diagram: 1. Passive integrator; 2. Active integrator; 3. High-pass filter module; 4. Voltage follower; 5. Oscilloscope. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application are described clearly and completely below. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are also within the scope of protection of this application.

[0045] See Figures 1 to 8 As shown, this application provides an ultra-wideband response performance extension circuit for a capacitive inductive voltage sensor. A hybrid integration circuit is inserted into the capacitive inductive voltage sensor to form a hybrid voltage sensor. The hybrid voltage sensor improves the low-frequency and high-frequency response capability of the induced voltage through the hybrid integration circuit.

[0046] The hybrid voltage sensor is composed of an integrating circuit module, a high-pass filter module 3, and a voltage follower 4 cascaded together. The integrating circuit module is used to measure the voltage of the conductor being measured in differential mode. The differential signal is integrated and restored. The high-pass filter module 3 is used to filter out the DC bias voltage introduced in the integration circuit module. The voltage follower 4 is used to achieve output impedance matching and signal isolation, ensuring the integrity of the high-frequency signal and the stability of the low-frequency response.

[0047] When performing voltage signal measurement, the conductor voltage generated by the conductor under test The differential signal is transmitted to the integrating circuit module, which integrates and restores it, and expands the amplitude-frequency response range of the measured voltage signal. This effectively improves the response accuracy and stability of the sensor in the ultra-wide frequency band, especially significantly improving the integration and restoration effect in the low frequency band, while avoiding distortion caused by parasitic parameters in the high frequency band.

[0048] The signal is then filtered by a high-pass filter module 3 to eliminate DC drift components and prevent cumulative errors from affecting measurement accuracy. The voltage follower 4 then achieves impedance matching between the output and the subsequent equipment to ensure that the signal is not distorted during transmission.

[0049] Optionally, the integration circuit module is composed of a passive integrator 1 and an active integrator 2 connected in series. The passive integrator 1 operates in self-integration mode and is used to perform preliminary integration processing on low-frequency signals to suppress high-frequency noise interference. The active integrator 2 operates in differentiation mode and performs integration and restoration on high-frequency signals. The active integrator 2 and the passive integrator 1 work together to broaden the measurement bandwidth and improve the consistency of the full-frequency response.

[0050] The active integrator 2 is connected in series with the high-pass filter module 3.

[0051] In this embodiment, the conductor voltage generated by the conductor under test The differential signal first passes through passive integrator 1, where it performs preliminary integration and reconstruction of the low-frequency signal in self-integration mode, effectively suppressing the coupling of high-frequency noise. It then enters active integrator 2, where it performs compensated integration of the high-frequency signal in differential mode, achieving continuous signal reconstruction and amplitude-frequency characteristic balance across a wide bandwidth. Through the cascaded collaboration of passive integrator 1 and active integrator 2, the hybrid voltage sensor maintains stable transfer function characteristics over an ultra-wide frequency range, ensuring accurate response and output of voltage signals with different frequency components.

[0052] Optionally, the passive integrator 1 is composed of a load resistor R. m It consists of coupling capacitor C1 and load capacitor C2;

[0053] Wherein, the input terminal of the coupling capacitor C1 is connected to the voltage of the conductor being measured. The positive terminal is connected to the positive terminal, and the output terminal is connected to the input terminal of the load resistor Rm. The output terminal of the load resistor Rm is connected to the voltage of the conductor being measured. The negative terminals are connected to form a closed loop. The load capacitor C2 is connected in parallel across the two ends of the load resistor Rm away from the active integrator 2, and the load capacitor C2 is grounded.

[0054] In this embodiment, the coupling capacitor C1 is the induced capacitance between the sensor and the conductor under test, and is a key component of the sensor's test capacitance. The load capacitor C2 is the structural capacitance of the sensor itself; that is, the sensor is essentially a large capacitor, and together with the coupling capacitor C1 between them, they form a capacitive voltage divider structure. The load resistor Rm, along with the coupling capacitor C1 and the load capacitor C2, jointly determine the lower limit of the low-frequency response, ensuring that the cutoff frequency is much lower than the lowest frequency component of the measured signal, thereby achieving an effective response in the low-frequency range.

[0055] Optionally, the active integrator 2 consists of an operational amplifier A1 and an input resistor. Feedback capacitor and feedback resistor ;

[0056] The non-inverting input of operational amplifier A1 is connected to the input of the load resistor Rm, and the inverting input is connected to the input resistor. A feedback resistor is connected in parallel between the inverting input and output of the operational amplifier A1 and the output terminal of the load resistor Rm. The feedback resistor With feedback capacitor Series connection.

[0057] In this embodiment, operational amplifier A1 provides high-gain amplification capability and virtual short (virtual ground) characteristics, through the input resistor. The input voltage is converted into current flowing into the summation point (virtual ground point), and the feedback capacitor... As the core energy storage element for integral calculation, its voltage changes with the integral of the input current, achieving precise compensation for high-frequency signals; feedback resistor Used to suppress DC drift and the accumulation of low-frequency noise, avoid output saturation, and ensure long-term stable operation of the integrator.

[0058] It should be noted that the feedback capacitor The voltage at one end is the virtual ground, and the voltage at the other end is the output voltage.

[0059] Optionally, the high-pass filter consists of a resistor. and capacitor constitute;

[0060] Wherein, the capacitor The input terminal is connected in series with the output terminal of the operational amplifier A1, and the capacitor The output terminal and the resistor One end is connected to the resistor. The other end is connected to the load capacitor C2 and grounded; the resistor The two ends on the side furthest from the active integrator 2 are connected in parallel with the voltage follower 4.

[0061] In this embodiment, the capacitor Used to filter out low-frequency noise, resistor Converting current signals into voltage signals facilitates subsequent circuit processing and measurement; capacitors... and resistance Together they form a filter structure, effectively suppressing low-frequency interference and improving the system's response to high-frequency signals.

[0062] Optionally, the voltage follower 4 is composed of an operational amplifier A2, an input resistor R2, and a resistor R3;

[0063] The non-inverting input terminal of the operational amplifier A2 is connected in series with the input resistor R2 and then connected to the resistor via a transmission line. The input terminal of operational amplifier A2 is connected to the inverting input terminal via resistor R3; and the output terminal of operational amplifier A2 is directly connected to the inverting input terminal via resistor R3.

[0064] An oscilloscope 5 is connected in series between the output terminal of the operational amplifier A2 and the output terminal of the load capacitor C2. The oscilloscope 5 is used to display the output voltage. Waveform.

[0065] In this embodiment, the input resistor R2 is used to limit the input current and protect the input stage of the operational amplifier A1. The input resistors R2 and R3 have equal resistance values, providing a DC negative feedback path to stabilize the DC operating point of the operational amplifier A1 and prevent output saturation due to the accumulation of input bias current.

[0066] Meanwhile, operational amplifier A1 provides virtual short characteristics. Due to the extremely high open-loop gain of the op-amp, under the action of negative feedback, the voltage at its inverting input terminal is forced to follow the voltage at its non-inverting input terminal, thereby achieving consistency between the input voltage and the output voltage, and realizing the isolation and transmission of electrical signals.

[0067] Optionally, a resistor R4 with a resistance of 50Ω is connected in series between the output terminal of the operational amplifier A2 and the oscilloscope 5 to achieve impedance matching of the transmission line, ensuring that the signal is not reflected or attenuated due to impedance mismatch during transmission, thereby ensuring signal integrity and measurement accuracy.

[0068] A test method for extending the ultra-wideband response performance of a capacitive inductive voltage sensor includes the following steps:

[0069] S1. Obtain the design parameters of the capacitive inductive voltage sensor and obtain the equivalent circuit diagram of the capacitive inductive voltage sensor without the insertion of the hybrid integration circuit;

[0070] S2. Using the equivalent circuit diagram, determine the influencing factors of the corner frequency of the capacitive induction voltage sensor measurement system, optimize the parameters of each capacitor and resistor in the hybrid integration circuit, and make the measurement loop in a self-integrating state over a wide frequency range.

[0071] S3. Insert the optimized hybrid integration circuit into the measurement circuit of the capacitive induction voltage sensor to obtain the hybrid voltage sensor;

[0072] S4. Perform a frequency response test on the hybrid voltage sensor. Use a signal generator to input voltage signals of different frequencies, record the output voltage waveform displayed on the oscilloscope 5, and verify the effectiveness of the hybrid voltage sensor in the low-frequency to high-frequency range.

[0073] Optionally, the equivalent circuit diagram includes coupling capacitor C1, load capacitor C2, and input resistance R2;

[0074] The coupling capacitor C1 is connected in series with the input resistor R2, and the input terminal of the coupling capacitor C1 is connected to the voltage of the conductor being measured. The positive terminal of the input resistor R2 is connected to the positive terminal of the conductor being measured, and the output terminal of the input resistor R2 is connected to the voltage of the conductor being measured. The negative terminal of the input resistor R2 is connected to the load capacitor C2 in parallel on one side of the input resistor R2, which is close to the coupling capacitor C1. The other side is connected in parallel with an oscilloscope 5. The oscilloscope 5 is used to acquire the output voltage waveform across the input resistor R2.

[0075] The actual impact of hybrid integrator circuit parameter optimization on the system frequency response has not been verified; experimental comparison of the amplitude-frequency response curves with and without the circuit is necessary. The parameters of the electronic components in the hybrid integrator circuit are selected as shown in the table below:

[0076] parameter value parameter value [C1] 340fF [C2] 34pF [R m ]] 3MΩ [R1] 100Ω [C f ]]> 1μF [R f ]] 330kΩ <![CDATA[C h ]]> 10μF <![CDATA[R h ]]> 33kΩ <![CDATA[R3]]> 200Ω <![CDATA[R2]]> 200Ω

[0077] A capacitive voltage sensor (i.e., a hybrid voltage sensor) inserted into a hybrid integrator circuit was tested by applying a 5Hz sinusoidal voltage and a steep wave with a rise time on the order of 10MHz. The test results are as follows. Figure 6 , Figure 7 As shown in the figure. The test results show that the hybrid voltage sensor can achieve good waveform reproduction for sinusoidal signals as low as 5Hz and steep waves up to 10MHz, while maintaining a stable voltage division ratio.

[0078] To further verify the effect of the hybrid sensor on the reconstruction of the sensed signal, the output waveforms with and without the hybrid integrator circuit were compared and tested. The results are as follows: Figure 8 As shown. The test conditions were an input signal frequency of 1kHz and an amplitude of 10V. Without the hybrid integrator circuit inserted, the sensor operated in the differential state, with the output signal phase leading by π / 2 and the amplitude significantly attenuated. However, after insertion, the output signal phase was consistent with the input, and the amplitude was accurately restored according to the designed voltage division ratio, verifying the effective suppression of phase and amplitude distortion by the hybrid integrator circuit over a wide frequency range.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A circuit for extending the ultra-wideband response performance of a capacitive inductive voltage sensor, characterized in that: The mixed integral circuit is inserted into the capacitive induced voltage sensor to form a mixed voltage sensor, and the mixed voltage sensor improves the low-frequency and high-frequency response capability to the induced voltage through the mixed integral circuit. The mixed voltage sensor is composed of an integral circuit module, a high-pass filter module (3) and a voltage follower (4) in cascade, the integral circuit module is used for integral reduction of differential signals of the measured conductor voltage in the differential mode, the high-pass filter module (3) is used for filtering out the direct current bias voltage introduced in the integral circuit module, and the voltage follower (4) is used for realizing output impedance matching and signal isolation, ensuring the integrity of high-frequency signals and the stability of low-frequency response.

2. The ultra-wideband response performance extension circuit of a capacitive inductive voltage sensor according to claim 1, characterized in that: The integral circuit module is formed by connecting a passive integrator (1) and an active integrator (2) in series, wherein the passive integrator (1) works in a self-integration mode and is used for performing preliminary integration processing on a low-frequency signal and suppressing high-frequency noise interference, and the active integrator (2) works in a differentiation mode and is used for performing integral restoration on a high-frequency signal, and the active integrator (2) and the passive integrator (1) work cooperatively to widen a measurement frequency band and improve full-frequency domain response consistency. The active integrator (2) is connected in series with the high-pass filter module (3).

3. The ultra-wideband response performance extension circuit of a capacitive inductive voltage sensor according to claim 2, characterized in that: The passive integrator (1) is formed by a load resistor Rm, a coupling capacitor C1 and a load capacitor C2. Wherein, the input end of the coupling capacitor C1 is connected with the positive end of the measured conductor voltage , the output end is connected with the input end of the load resistor Rm, the output end of the load resistor Rm is connected with the negative end of the measured conductor voltage , a closed loop is formed, the load capacitor C2 is connected in parallel to the two ends of the load resistor Rm away from the active integrator (2), and the load capacitor C2 is grounded.

4. The ultra-wideband response performance extension circuit of a capacitive inductive voltage sensor according to claim 3, characterized in that: The active integrator (2) is composed of an operational amplifier Al, an input resistance , a feedback capacitance and a feedback resistance ; The non-inverting input of the operational amplifier A1 is connected with the input of the load resistor Rm, the inverting input is connected with the output of the load resistor Rm through an input resistor , the feedback resistor is connected in parallel between the inverting input and the output of the operational amplifier A1, and the feedback resistor is connected in series with the feedback capacitor .

5. The ultra-wideband response performance extension circuit of a capacitive inductive voltage sensor according to claim 4, characterized in that: The high-pass filter is composed of a resistor and a capacitor ; The input end of the capacitor is connected in series to the output end of the operational amplifier A1, the output end of the capacitor is connected to one end of the resistor , the other end of the resistor is connected to the load capacitor C2 and grounded; the resistor is connected in parallel to the voltage follower (4) at both ends away from the active integrator (2).

6. The ultra-wideband response performance extension circuit of a capacitive inductive voltage sensor according to claim 5, characterized in that: The voltage follower (4) is formed by operational amplifiers A1A2, an input resistor R2 and a resistor R3. Wherein, the non-inverting input terminal of the operational amplifier A1A2 is connected with the input terminal of the resistor R2 through a transmission line, the output terminal of the operational amplifier A1A2 is directly connected with the inverting input terminal through the resistor R3 , and the output terminal of the operational amplifier A1A2 is connected with the inverting input terminal of the operational amplifier A2 through the resistor R4. An oscilloscope (5) is connected in series between the output of the operational amplifier A1A2 and the output of the load capacitor C2, for displaying the output voltage waveform.

7. A circuit for extending the ultra-wide frequency response of a capacitive inductive voltage sensor according to claim 6, wherein: A resistor R4 is connected in series between an output end of the operational amplifiers A1A2 and the oscilloscope (5).

8. A test method for extending the ultra-wideband response performance of a capacitive inductive voltage sensor, characterized in that: The method comprises the following steps: S1. Obtaining design parameters of the capacitive induced voltage sensor to obtain an equivalent circuit diagram of the capacitive induced voltage sensor without the mixed integral circuit; S2. Determining, through the equivalent circuit diagram, influencing factors of a turning frequency of the capacitive induced voltage sensor measurement system, optimizing parameters of each capacitor and resistor in the mixed integral circuit, and making the measurement loop in a self-integration state in a wide frequency range; S3. Inserting the optimized mixed integral circuit into the measurement loop of the capacitive induced voltage sensor to obtain the mixed voltage sensor; S4. Performing frequency response testing on the mixed voltage sensor, inputting voltage signals of different frequencies by using a signal generator, recording output voltage waveforms displayed by the oscilloscope (5), and verifying effectiveness of the mixed voltage sensor in a low-frequency to high-frequency range.

9. The method of claim 8, wherein the method further comprises: applying a voltage to the capacitor; and measuring the voltage across the capacitor. The equivalent circuit diagram comprises the coupling capacitor C1, the load capacitor C2 and the input resistor R2. The coupling capacitor C1 is connected in series with the input resistor R2, the input end of the coupling capacitor C1 is connected with the positive end of the measured conductor voltage , the output end of the input resistor R2 is connected with the negative end of the measured conductor voltage , the input resistor R2 is provided in parallel with the load capacitor C2 on one side close to the coupling capacitor C1, and provided in parallel with an oscilloscope (5) on the other side, the oscilloscope (5) is used for collecting the output voltage waveform between the input resistor R2.

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