Fluxgate voltage sensor

Abstract

The invention provides a fluxgate voltage sensor. The voltage sensor comprises a high-voltage module, a low-voltage module and an isolation power supply, the high-voltage module comprises a high-voltage input Vi, divider resistor networks R1-R6, multiplexers U1 and U2, a differential operational amplifier A1, an error operational amplifier A2, a sampling resistor R7, a compensation capacitor C1, a main fluxgate sensor DCCT1, an auxiliary fluxgate current sensor DCCT2 and a measuring resistor RM. And the detection precision of the voltage sensor is improved.

Description

Technical Field

[0001] The present invention relates to the field of voltage sensors, and in particular to a fluxgate voltage sensor. Background Art

[0002] The fluxgate current sensor for high voltage measurement disclosed in the prior art is used for high voltage measurement. The high voltage signal 1 is connected to the two ends of HV+ and HV-. The high voltage 1 is converted into a small current through a resistor. The small current passes through a skeleton wound on a magnetic core 4 to form a winding 3 with multiple turns, so that the fluxgate sensor with 4, 5, and 6 as a whole can double the primary current to achieve a doubling of the signal-to-noise ratio; 6 is a zero flux detector. When a current flows through 3, 6 will be affected by the magnetic potential caused by the current in 3 on the magnetic core 4, thereby generating high-order harmonics. After filtering, amplification and other circuits, the compensation current is introduced into the compensation winding 5 wound on the magnetic core 4 to generate an opposite magnetic potential on 4 to that generated by 3 on 4, which is equal in magnitude, so that the magnetic flux in 6 returns to 0. At this time, the high voltage 1 is linearly related to the compensation current Is, and the voltage Um generated by Is on the measuring resistor 7 is linearly related to the high voltage 1. The magnitude of the high voltage 1 can be obtained by measuring the magnitude of Um.

[0003] Disadvantages: High-voltage measurement requires a large input impedance, and direct series connection will result in very small currents in 3. The current enhanced by equal ampere-turns greatly limits the bandwidth of the sensor due to the increase in windings, inductance, and parasitic capacitance. At the same time, the temperature coefficient of 2 has a greater impact on the accuracy of the entire machine. 6 is not a closed-loop system, the zero point offset is large, and due to the influence of residual magnetism, the zero point is extremely unstable, and the accuracy of the entire machine is low under small voltages. The entire machine has only one range and a small dynamic range.

[0004] In summary, the accuracy of the voltage sensor in the prior art is low. Summary of the invention

[0005] In view of the above problems, the present invention is proposed to provide a fluxgate voltage sensor that overcomes the above problems or at least partially solves the above problems.

[0006] According to one aspect of the present invention, a fluxgate voltage sensor is provided, the voltage sensor comprising: a high voltage module, a low voltage module and a fluxgate sensor;

[0007] The high voltage module and the low voltage module are connected via the fluxgate sensor.

[0008] Optionally, the high voltage module includes: a high voltage input V i , a voltage-dividing resistor network, a first multiplexer U1 and a second multiplexer U2, a differential operational amplifier A1, an error operational amplifier A2, a fourth power amplifier A4, a second zero-flux detection winding W 23, sampling resistor R7 and compensation capacitor C1;

[0009] The voltage divider resistor network is connected in parallel with the high voltage input V i at both ends;

[0010] The voltage-dividing resistor network specifically includes: a first voltage-dividing resistor R1, a second voltage-dividing resistor R2, ..., a sixth voltage-dividing resistor R6, which are connected in series in sequence;

[0011] The input end of the first voltage-dividing resistor R1 is connected to the high voltage input V i The output end of the sixth voltage-dividing resistor R6 is connected to the positive electrode of the high voltage input V i The negative connection of

[0012] The output end of the first voltage-dividing resistor R1 and the output end of the second voltage-dividing resistor R2 are respectively connected to the input end of the first multiplexer U1;

[0013] The output end of the fourth voltage-dividing resistor R4 and the output end of the fifth voltage-dividing resistor R5 are respectively connected to the input end of the second multiplexer U2;

[0014] The output ends of the first multiplexer U1 and the second multiplexer U2 are respectively connected to the input end of the differential operational amplifier A1, and the output end of the differential operational amplifier A1 is connected to the input end of the error operational amplifier A2;

[0015] The other input terminal of the error amplifier A2 is connected to the sampling resistor R7;

[0016] One end of the compensation resistor C1 is connected to the input end of the error amplifier A2, and the other end is connected to the output end of the error amplifier A2.

[0017] Optionally, the fluxgate sensor specifically includes: a main fluxgate sensor DCCT1 and an auxiliary fluxgate current sensor DCCT2;

[0018] The primary winding of the main fluxgate sensor DCCT1 is W 11 , the secondary winding is W 12 ;

[0019] The primary winding of the auxiliary fluxgate sensor DCCT2 is W 21 , the secondary winding is W 22 ;

[0020] The primary winding W of the main fluxgate sensor DCCT1 11 One end is connected to the output end of the error amplifier A2, and the other end is grounded;

[0021] The secondary winding W of the auxiliary fluxgate sensor DCCT2 22 One end of is connected to another input end of the error amplifier, and the other end is connected to the input end of the fourth power amplifier A4;

[0022] The output end of the fourth power amplifier A4 is connected to the second zero flux detection winding W 23 connect.

[0023] Optionally, the low voltage module specifically includes: a first zero flux detector W 13 and a third power amplifier A3;

[0024] The secondary winding W of the main fluxgate sensor DCCT1 12 One end of the auxiliary fluxgate sensor DCCT2 is connected to the primary winding W 21 One end of is connected in series;

[0025] The other end is connected to the input end of the third power amplifier A3;

[0026] The output end of the third power amplifier A3 is connected to the first zero flux detector W 13 connect;

[0027] The primary winding W of the auxiliary fluxgate sensor DCCT2 21 The other end of the detection resistor R M One end of the detection resistor R M The other end of the ground connection.

[0028] The present invention provides a fluxgate voltage sensor, the voltage sensor comprising: a high voltage module, a low voltage module and an isolated power supply; the high voltage module comprises: a high voltage input V i , voltage divider resistor network R1~R6, multiplexers U1 and U2, differential op amp A1, error op amp A2, sampling resistor R7, compensation capacitor C1, main fluxgate sensor DCCT1, auxiliary fluxgate current sensor DCCT2, measuring resistor R M . The detection accuracy of the voltage sensor is improved.

[0029] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented according to the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0031] Figure 1 A schematic diagram of the structure of a fluxgate voltage sensor provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0032] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0033] The terms "comprises" and "having" and any variations thereof in the description embodiments, claims and drawings of the present invention are intended to cover non-exclusive inclusions, for example, including a series of steps or units.

[0034] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0035] like Figure 1 As shown, a fluxgate voltage sensor includes: a high voltage module, a low voltage module and an isolated power supply. The high voltage module is inside the dotted line frame, and the low voltage module is outside the dotted line.

[0036] The high voltage module includes: the high voltage input V i , a voltage-dividing resistor network, a first multiplexer U1 and a second multiplexer U2, a differential operational amplifier A1, an error operational amplifier A2, a fourth power amplifier A4, a second zero-flux detection winding W 23 , sampling resistor R7 and compensation capacitor C1;

[0037] The voltage divider resistor network is connected in parallel to the high voltage input V i The two ends of the circuit convert the high voltage into a low voltage signal for subsequent circuit processing.

[0038] The voltage-dividing resistor network specifically includes: a first voltage-dividing resistor R1, a second voltage-dividing resistor R2, ..., a sixth voltage-dividing resistor R6, which are connected in series in sequence; wherein the first voltage-dividing resistor R1 and the sixth voltage-dividing resistor R6 are high-voltage arms, the third voltage-dividing resistor R3 and the fourth voltage-dividing resistor R4 are low-range voltage-dividing arms, and the second voltage-dividing resistor R2 and the fifth voltage-dividing resistor R5 are high-range voltage-dividing arms, thus realizing the effect of a multiplexer, wherein the low-range selects the voltage across the third voltage-dividing resistor R3 and the fourth voltage-dividing resistor R4 to the output end; and the high-range selects the voltage across the second voltage-dividing resistor R2 and the fifth voltage-dividing resistor R5 to the output end.

[0039] The input end of the first voltage divider resistor R1 is connected to the high voltage input V i The positive electrode of the sixth voltage divider resistor R6 is connected to the high voltage input V i The negative connection of

[0040] The output end of the first voltage-dividing resistor R1 and the output end of the second voltage-dividing resistor R2 are respectively connected to the input end of the first multiplexer U1;

[0041] The output end of the fourth voltage-dividing resistor R4 and the output end of the fifth voltage-dividing resistor R5 are respectively connected to the input end of the second multiplexer U2;

[0042] The output ends of the first multiplexer U1 and the second multiplexer U2 are respectively connected to the input end of the differential operational amplifier A1, and the output end of the differential operational amplifier A1 is connected to the input end of the error operational amplifier A2; the differential operational amplifier A1 amplifies the output signal of the multiplexer in proportion;

[0043] The other input terminal of the error amplifier A2 is connected to the sampling resistor R7;

[0044] Error amplifier A2 compares the voltage obtained by sampling resistor R7 from compensation current Is2 of DCCT2 with the output voltage of differential amplifier A1. If Is2*R7>V A2 , reduce the output voltage, Is2 will decrease proportionally until Is2*R7=V A2 ; If Is2*R7 <V A2 , reduce the output voltage, Is2 will increase proportionally until Is2*R7=V A2 ; So that Is2=V A2 / R7.

[0045] One end of the compensation resistor C1 is connected to the input end of the error amplifier A2, and the other end is connected to the output end of the error amplifier A2. The compensation resistor C1 is used to phase compensate the capacitor to eliminate the oscillation that may be caused by the time difference of the electric / magnetic and magneto-electric conversion in DCCT1 and DCCT2, which is unfavorable to the circuit.

[0046] The fluxgate sensor specifically includes: a main fluxgate sensor DCCT1 and an auxiliary fluxgate current sensor DCCT2;

[0047] The primary winding of the main fluxgate sensor DCCT1 is W 11 , the secondary winding is W 12 ;

[0048] The primary winding of the auxiliary fluxgate sensor DCCT2 is W 21 , the secondary winding is W 22 ;

[0049] Primary winding W of main fluxgate sensor DCCT1 11 One end is connected to the output end of the error amplifier A2, and the other end is grounded;

[0050] The secondary winding W of the auxiliary fluxgate sensor DCCT2 22 One end is connected to the other input end of the error amplifier, and the other end is connected to the input end of the fourth power amplifier A4;

[0051] The output terminal of the fourth power amplifier A4 is connected to the second zero flux detection winding W 23 connect.

[0052] The low voltage module specifically includes: a first zero flux detector W 13 and a third power amplifier A3;

[0053] The secondary winding W of the main fluxgate sensor DCCT1 12 One end of the auxiliary fluxgate sensor DCCT2 is connected to the primary winding W 21 One end of is connected in series;

[0054] The other end is connected to the input end of the third power amplifier A3;

[0055] The output terminal of the third power amplifier A3 is connected to the first zero flux detector W 13 connect;

[0056] The primary winding W of the auxiliary fluxgate sensor DCCT2 21 The other end of the detection resistor R M Connect one end of the detection resistor R M The other end of the ground connection.

[0057] From the principle of DCCT, we know that due to the existence of zero flux detector, the primary winding W of auxiliary fluxgate sensor DCCT2 21 The current in the secondary winding W 22 There is a proportional relationship between the current in 21 =k2*I 22The secondary winding W12 of the main fluxgate sensor DCCT1 is connected in series with the primary winding W21 of the auxiliary fluxgate sensor DCCT2, ie I 11 =K1*K2*I 22 ;

[0058] The third power amplifier A3 and the fourth power amplifier A4 output the compensation current I in proportion to the signal of the zero flux detector. 12 ,I 22 .

[0059] Example job description:

[0060] Taking 2kV high voltage input as an example, the voltage divider resistors R1 = 9.99MΩ, R2 = 9k, R3 = 1k, R4 = 1k, R5 = 9k, R6 = 9.99M;

[0061] When the range is high, the multiplexer outputs a voltage of 200mV across R3 and R4, which is amplified 10 times to 2V by the differential amplifier. The sampling resistor is 10Ω, so I 11 =200mA, if K1=10, K2=0.1; then I 12 =2A,I 22 =200mA, if R M =1Ω, the output voltage of the sensor is 2V;

[0062] The sensor ratio is 2000V / 2V.

[0063] Taking 10V high voltage input as an example, the voltage divider resistor R1=9.99MΩ, R2=9k, R3=1k, R4=1k, R5=9k, R6=9.99M; at this time, the range should be switched to low range, the multiplexer outputs 10mV voltage across R3 and R4, which is amplified 10 times to 100mV by the differential amplifier; the sampling resistor is 10Ω, then I11=10mA, if K1=10, K2=0.1; then I 12 =100mA, I 22 =10mA, if R M =1Ω, the output voltage of the sensor is 100mV; the input-output ratio is 10V / 100mV, and the sensor ratio is still 2000V / 2V.

[0064] Beneficial effects:

[0065] The present invention achieves multiple ranges without changing the input impedance (R1+R2+...+R6), so that the dynamic range of the entire sensor is larger;

[0066] The magnetic core and zero flux detector of the present invention are complete ring structures, without magnetic leakage, and the primary winding W 11 With the secondary winding W12 The current ratio is more accurate, the precision is higher, and the repeatability is better;

[0067] The ratio K2 of the auxiliary fluxgate sensor DCCT2 further corrects the accuracy reduction caused by the accuracy problem of R7 itself; at the same time, the existence of k2 of the auxiliary fluxgate sensor DCCT2 feeds the output current back to R7, making A1, DCCT1, DCCT2 and R M The closed-loop system formed has higher accuracy.

[0068] The above specific implementation methods further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific implementation methods of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A fluxgate voltage sensor, characterized in that: The voltage sensor comprises: High voltage module, low voltage module and fluxgate sensor; The high voltage module and the low voltage module are connected via the fluxgate sensor.

2. A fluxgate voltage sensor according to claim 1, characterized in that: The high voltage module includes: a high voltage input V i , a voltage-dividing resistor network, a first multiplexer U1 and a second multiplexer U2, a differential operational amplifier A1, an error operational amplifier A2, a fourth power amplifier A4, a second zero-flux detection winding W 23 , sampling resistor R7 and compensation capacitor C1; The voltage divider resistor network is connected in parallel with the high voltage input V i at both ends; The voltage-dividing resistor network specifically includes: a first voltage-dividing resistor R1, a second voltage-dividing resistor R2, ..., a sixth voltage-dividing resistor R6, which are connected in series in sequence; The input end of the first voltage-dividing resistor R1 is connected to the high voltage input V i The output end of the sixth voltage-dividing resistor R6 is connected to the positive electrode of the high voltage input V i The negative connection of The output end of the first voltage-dividing resistor R1 and the output end of the second voltage-dividing resistor R2 are respectively connected to the input end of the first multiplexer U1; The output end of the fourth voltage-dividing resistor R4 and the output end of the fifth voltage-dividing resistor R5 are respectively connected to the input end of the second multiplexer U2; The output ends of the first multiplexer U1 and the second multiplexer U2 are respectively connected to the input end of the differential operational amplifier A1, and the output end of the differential operational amplifier A1 is connected to the input end of the error operational amplifier A2; The other input terminal of the error amplifier A2 is connected to the sampling resistor R7; One end of the compensation resistor C1 is connected to the input end of the error amplifier A2, and the other end is connected to the output end of the error amplifier A2.

3. A fluxgate voltage sensor according to claim 2, characterized in that: The fluxgate sensor specifically includes: a main fluxgate sensor DCCT1 and an auxiliary fluxgate current sensor DCCT2; The primary winding of the main fluxgate sensor DCCT1 is W 11 , the secondary winding is W 12 ; The primary winding of the auxiliary fluxgate sensor DCCT2 is W 21 , the secondary winding is W 22 ; The primary winding W of the main fluxgate sensor DCCT1 11 One end is connected to the output end of the error amplifier A2, and the other end is grounded; The secondary winding W of the auxiliary fluxgate sensor DCCT2 22 One end of is connected to another input end of the error amplifier, and the other end is connected to the input end of the fourth power amplifier A4; The output end of the fourth power amplifier A4 is connected to the second zero flux detection winding W 23 connect.

4. A fluxgate voltage sensor according to claim 3, characterized in that: The low voltage module specifically includes: a first zero flux detector W 13 and a third power amplifier A3; The secondary winding W of the main fluxgate sensor DCCT1 12 One end of the auxiliary fluxgate sensor DCCT2 is connected to the primary winding W 21 One end of is connected in series; The other end is connected to the input end of the third power amplifier A3; The output end of the third power amplifier A3 is connected to the first zero flux detector W 13 connect; The primary winding W of the auxiliary fluxgate sensor DCCT2 21 The other end of the detection resistor R M One end of the detection resistor R M The other end of the ground connection.

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