TMR sensor-based non-contact current measuring device

Abstract

A TMR sensor-based non-contact current measuring device, comprising a TMR sensor module, a differential processing module, a signal processing module, and an intelligent control module. The TMR sensor module is used for acquiring a detection signal and transmitting the detection signal to the differential processing module; the differential processing module is used for performing differential amplification, filtering and conversion processing on the detection signal to output a single-ended signal; the signal processing module is used for performing inverting amplification processing on the single-ended signal to obtain a control signal; and the intelligent control module is used for receiving the control signal and implementing control. According to the TMR sensor-based non-contact current measuring device, a current detection signal is obtained on the basis of the TMR sensor module, differential amplification, filtering and conversion processing are performed on the current detection signal by means of the differential processing module to output a single-ended signal, and inverting amplification processing is performed on the single-ended signal by means of the signal processing module, thereby improving the detection signal precision, and thus improving the accuracy of current detection.

Description

A non-contact current measuring device based on TMR sensor Technical Field

[0001] The present invention relates to the technical field of current measurement, and in particular to a non-contact current measuring device based on a TMR sensor. Background Art

[0002] Current is an important parameter in the power system, and its accurate measurement is of great significance. With the development of sensing technology, non-contact current measurement has been widely used. The current non-contact current measurement technology mainly uses a surrounding method to measure the magnetic field around the conductor, specifically using TMR sensors to achieve non-contact current detection. This method has no effect on the current to be measured and is relatively safe. However, the existing non-contact current measurement device based on TMR sensors has low current measurement accuracy, cannot perform autonomous gain adjustment, and has low signal detection accuracy.

[0003] Summary of the Invention

[0004] The present invention aims to provide a non-contact current measuring device based on a TMR sensor to solve the above-mentioned technical problems. The device obtains a current detection signal based on a TMR sensor module and performs differential amplification, filtering and conversion processing on the current detection signal by a differential processing module to output a single-ended signal. The single-ended signal is then subjected to inverting amplification processing by a signal processing module to improve the detection signal precision and thereby improve the accuracy of current detection.

[0005] In order to solve the above technical problems, the present invention provides a non-contact current measurement device based on a TMR sensor, comprising a TMR sensor module, a differential processing module, a signal processing module and an intelligent control module; wherein:

[0006] The TMR sensor module is used to obtain a detection signal and transmit the detection signal to the differential processing module;

[0007] The differential processing module is used to perform differential amplification, filtering and conversion processing on the detection signal and output a single-ended signal;

[0008] The signal processing module is used to perform inverse amplification processing on the single-ended signal to obtain a control signal;

[0009] The intelligent control module is used to receive control signals and implement control.

[0010] In the above scheme, the current detection signal is obtained based on the TMR sensor module and the differential processing module performs differential amplification, filtering and conversion on the current detection signal to output a single-ended signal. The single-ended signal is inverted and amplified by the signal processing module to improve the detection signal accuracy, thereby improving the accuracy of current detection.

[0011] Furthermore, the differential processing module includes a first amplifier stage circuit, a filter circuit, and a second amplifier stage circuit; wherein:

[0012] The first amplifier stage circuit is used to perform differential amplification processing on the detection signal to obtain a differential current signal;

[0013] The filtering circuit is used to filter the differential current signal to obtain a filtered differential current signal;

[0014] The second amplifier stage circuit is used to convert the filtered differential current signal into a single-ended signal and output it to the signal processing module.

[0015] Furthermore, the TMR sensor module measures the magnetic field around the measured conductor in a surrounding manner and converts the magnetic field into an electrical signal to obtain a detection signal; the TMR sensor module includes a first sensor, a second sensor, a third sensor, a fourth sensor and a first power supply; wherein:

[0016] The first end of the first sensor is electrically connected to the first power supply, the second end of the first sensor is electrically connected to the first end of the third sensor, and the second end of the third sensor is grounded;

[0017] The first end of the second sensor is electrically connected to the first power supply, the second end of the second sensor is electrically connected to the first end of the fourth sensor, and the second end of the fourth sensor is grounded;

[0018] The first end of the third sensor and the first end of the fourth sensor are both electrically connected to the first amplifying stage circuit to transmit the detection signal to the differential processing module.

[0019] Furthermore, the first amplifier stage circuit includes a first resistor, a second resistor, a third resistor, a fourth resistor and a first amplifier; wherein:

[0020] One end of the first resistor is electrically connected to the TMR sensor module, and the other end is electrically connected to the inverting end of the first amplifier;

[0021] One end of the second resistor is electrically connected to the TMR sensor module, and the other end is electrically connected to the in-phase terminal of the first amplifier;

[0022] One end of the third resistor is electrically connected to the inverting end of the first amplifier, and the other end is electrically connected to the first output end of the first amplifier;

[0023] One end of the fourth resistor is electrically connected to the in-phase terminal of the first amplifier, and the other end is electrically connected to the second output terminal of the first amplifier;

[0024] The first amplifier stage circuit is electrically connected to the filter circuit via the first amplifier first output terminal and the first amplifier second output terminal.

[0025] Furthermore, the filtering circuit includes a fifth resistor, a sixth resistor and a first capacitor; wherein:

[0026] One end of the fifth resistor is electrically connected to the first output end of the first amplifier, and the other end is electrically connected to one end of the first capacitor;

[0027] One end of the sixth resistor is electrically connected to the second output end of the first amplifier, and the other end is electrically connected to the other end of the first capacitor;

[0028] The filter circuit is electrically connected to the second amplifier stage circuit via the first capacitor.

[0029] Furthermore, the second amplifier stage circuit includes a second amplifier and a seventh resistor; wherein:

[0030] The non-inverting terminal of the second amplifier is electrically connected to one end of the first capacitor, and the inverting terminal of the second amplifier is electrically connected to the other end of the first capacitor;

[0031] One end of the seventh resistor is electrically connected to the inverting end of the second amplifier, and the other end is electrically connected to the output end of the second amplifier;

[0032] The second amplifier stage circuit is electrically connected to the signal processing module via the second amplifier output terminal.

[0033] Furthermore, the signal processing module includes a first operational amplifier, an eighth resistor, a ninth resistor, and a tenth resistor; wherein:

[0034] The inverting terminal of the first operational amplifier is electrically connected to the output terminal of the second amplifier, and the non-inverting terminal of the first operational amplifier is grounded;

[0035] One end of the eighth resistor is electrically connected to the inverting terminal of the first operational amplifier, and the other end thereof is grounded via the ninth resistor;

[0036] One end of the tenth resistor is electrically connected to the inverting terminal of the first operational amplifier, and the other end is electrically connected to the output terminal of the first operational amplifier;

[0037] The output terminal of the first operational amplifier is electrically connected to the intelligent control module.

[0038] The present invention provides a non-contact current measuring device based on a TMR sensor, further comprising a gain adjustment circuit and a feedback adjustment circuit, wherein:

[0039] The gain adjustment circuit is used to increase the gain of the signal processing module when the single-ended signal input to the signal processing module is less than a preset first gain adjustment threshold or greater than a preset second gain adjustment threshold;

[0040] The feedback adjustment circuit is used to set a feedback coefficient for the signal processing module and adjust the gain of the signal processing module;

[0041] The signal processing module performs inverting amplification processing on the single-ended signal according to the working states of the gain adjustment circuit and the feedback adjustment circuit to obtain a control signal.

[0042] Furthermore, the gain adjustment circuit includes an eleventh resistor, a twelfth resistor, a first diode, a thirteenth resistor, a second operational amplifier, a fourteenth resistor, a second diode, a fifteenth resistor, a sixteenth resistor, a threshold setting unit, and a third operational amplifier; wherein:

[0043] One end of the eleventh resistor is electrically connected to the non-grounded end of the ninth resistor, and the other end is electrically connected to the cathode of the first diode; the anode of the first diode is electrically connected to the output end of the second operational amplifier;

[0044] One end of the twelfth resistor is electrically connected to the output terminal of the second operational amplifier, and the other end is electrically connected to the inverting terminal of the second operational amplifier;

[0045] One end of the thirteenth resistor is electrically connected to the inverting terminal of the second operational amplifier, and the other end is electrically connected to the output terminal of the first operational amplifier;

[0046] One end of the fourteenth resistor is electrically connected to the non-grounded end of the ninth resistor, and the other end is electrically connected to the cathode of the second diode; the anode of the second diode is electrically connected to the output end of the third operational amplifier;

[0047] One end of the fifteenth resistor is electrically connected to the output terminal of the third operational amplifier, and the other end is electrically connected to the inverting terminal of the third operational amplifier;

[0048] One end of the sixteenth resistor is electrically connected to the inverting terminal of the third operational amplifier, and the other end is electrically connected to the output terminal of the first operational amplifier;

[0049] The threshold setting unit is electrically connected to the non-inverting terminal of the second operational amplifier and the non-inverting terminal of the third operational amplifier, and is used to set the first feedback threshold as the first gain adjustment threshold and set the second feedback threshold as the second gain adjustment threshold; wherein:

[0050] When the single-ended signal input to the signal processing module is less than a first gain adjustment threshold, the second operational amplifier starts working, thereby increasing the gain of the first operational amplifier; when the single-ended signal input to the signal processing module is greater than the second gain adjustment threshold, the third operational amplifier starts working, thereby increasing the gain of the first operational amplifier.

[0051] Furthermore, the feedback regulation circuit includes a seventeenth resistor, a fourth operational amplifier, a third diode, a fourth diode and an eighteenth resistor; wherein:

[0052] One end of the seventeenth resistor is electrically connected to the non-grounded end of the ninth resistor, and the other end is electrically connected to the anode of the third diode, the cathode of the fourth diode, and the output end of the fourth operational amplifier;

[0053] The cathode of the third diode and the anode of the fourth diode are electrically connected to the inverting terminal of the fourth operational amplifier;

[0054] The non-inverting terminal of the fourth operational amplifier is grounded;

[0055] One end of the eighteenth resistor is electrically connected to the inverting terminal of the fourth operational amplifier, and the other end is electrically connected to the output terminal of the first operational amplifier; wherein:

[0056] When the single-ended signal input to the signal processing module does not reach the first gain adjustment threshold and the second gain adjustment threshold, the fourth operational amplifier operates to adjust the gain of the first operational amplifier.

[0057] The above-mentioned solution provides a non-contact current measurement device based on a TMR sensor, which uses a TMR sensor module to measure the magnetic field around a conductor in a surrounding manner, and then performs non-contact current measurement. The differential processing module performs differential amplification, filtering, and conversion processing on the detected signal and outputs a single-ended signal. The single-ended signal is further processed by the signal processing module to improve the detection signal precision and the accuracy of current detection. At the same time, the feedback adjustment circuit sets the feedback coefficient and adjusts the gain of the signal processing module. The gain adjustment circuit automatically adjusts the gain of the signal processing module according to the relationship between the single-ended signal and the set first gain adjustment threshold and second gain adjustment threshold, thereby further improving the signal precision. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] FIG1 is a schematic diagram showing the connection of modules of a non-contact current measurement device based on a TMR sensor according to an embodiment of the present invention;

[0059] FIG2 is a circuit diagram of a non-contact current measuring device based on a TMR sensor provided by one embodiment of the present invention;

[0060] FIG3 is a connection diagram of a gain adjustment circuit provided in one embodiment of the present invention;

[0061] FIG4 is a connection diagram of a feedback regulation circuit provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0062] The following will provide a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0063] Referring to FIG1 , this embodiment provides a non-contact current measurement device based on a TMR sensor, comprising a TMR sensor module, a differential processing module, a signal processing module, and an intelligent control module; wherein:

[0064] The TMR sensor module measures the magnetic field around the conductor in a surrounding manner, obtains a first voltage signal and a second voltage signal as detection signals, and transmits the detection signals to the differential processing module;

[0065] The differential processing module is connected to the TMR sensor module and is used to perform differential amplification, filtering and conversion processing on the first voltage signal and the second voltage signal, and output a single-ended signal;

[0066] The signal processing module is used to perform inverse amplification processing on the single-ended signal to obtain a control signal;

[0067] The intelligent control module is used to receive control signals and implement control.

[0068] In this embodiment, the TMR sensor module obtains the current detection signal and the differential processing module performs differential amplification, filtering and conversion processing on the current detection signal to output a single-ended signal. The single-ended signal is then inverted and amplified by the signal processing module to improve the detection signal precision and thus improve the accuracy of current detection.

[0069] Furthermore, the differential processing module includes a first amplifier stage circuit, a filter circuit, and a second amplifier stage circuit; wherein:

[0070] The first amplifier stage circuit is used to perform differential amplification processing on the detection signal to obtain a differential current signal;

[0071] The filtering circuit is used to filter the differential current signal to obtain a filtered differential current signal;

[0072] The second amplifier stage circuit is used to convert the filtered differential current signal into a single-ended signal and output it to the signal processing module.

[0073] Further, referring to FIG2 , the TMR sensor module measures the magnetic field around the measured conductor in a surrounding manner and converts the magnetic field into an electrical signal to obtain a detection signal; the TMR sensor module includes a first sensor J1, a second sensor J2, a third sensor J3, a fourth sensor J4 and a first power supply VCC1; wherein:

[0074] A first end of the first sensor J1 is electrically connected to the first power supply VCC1, a second end of the first sensor J1 is electrically connected to a first end of the third sensor J3, and a second end of the third sensor J3 is grounded;

[0075] A first end of the second sensor J2 is electrically connected to the first power supply VCC1, a second end of the second sensor J2 is electrically connected to a first end of the fourth sensor J4, and a second end of the fourth sensor J4 is grounded;

[0076] The first end of the third sensor J3 and the first end of the fourth sensor J4 are both electrically connected to the first amplifying stage circuit to transmit the detection signal to the differential processing module.

[0077] In a specific implementation process, the first sensor J1 , the second sensor J2 , the third sensor J3 and the fourth sensor J4 may all be TMR sensors, forming a bridge circuit, and the specific models are not limited.

[0078] Furthermore, the first amplifier stage circuit includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4 and a first amplifier U1; wherein:

[0079] One end of the first resistor R1 is electrically connected to the TMR sensor module, and the other end is electrically connected to the inverting end of the first amplifier U1;

[0080] One end of the second resistor R2 is electrically connected to the TMR sensor module, and the other end is electrically connected to the in-phase terminal of the first amplifier U1;

[0081] One end of the third resistor R3 is electrically connected to the inverting end of the first amplifier U1, and the other end is electrically connected to the first output end of the first amplifier U1;

[0082] One end of the fourth resistor R4 is electrically connected to the in-phase terminal of the first amplifier U1, and the other end is electrically connected to the second output terminal of the first amplifier U1;

[0083] The first amplifier stage circuit is electrically connected to the filter circuit via the first output terminal of the first amplifier U1 and the second output terminal of the first amplifier U1.

[0084] In this embodiment, the first amplifier stage circuit is used to perform differential amplification processing on the detection signal to obtain a differential current signal.

[0085] Furthermore, the filtering circuit includes a fifth resistor R5, a sixth resistor R6 and a first capacitor C1; wherein:

[0086] One end of the fifth resistor R5 is electrically connected to the first output end of the first amplifier U1, and the other end is electrically connected to one end of the first capacitor C1;

[0087] One end of the sixth resistor R6 is electrically connected to the second output end of the first amplifier U1, and the other end is electrically connected to the other end of the first capacitor C1;

[0088] The filter circuit is electrically connected to the second amplifier stage circuit via the first capacitor C1.

[0089] In this embodiment, the filtering circuit is used to filter the differential current signal to obtain a filtered differential current signal.

[0090] Furthermore, the second amplifier stage circuit includes a second amplifier U2 and a seventh resistor R7; wherein:

[0091] The non-inverting terminal of the second amplifier U2 is electrically connected to one end of the first capacitor C1, and the inverting terminal of the second amplifier U2 is electrically connected to the other end of the first capacitor C1;

[0092] One end of the seventh resistor R7 is electrically connected to the inverting end of the second amplifier U2, and the other end is electrically connected to the output end of the second amplifier U2;

[0093] The second amplifier stage circuit is electrically connected to the signal processing module via the output end of the second amplifier U2.

[0094] In this embodiment, the second amplifier stage circuit is used to convert the filtered differential current signal into a single-ended signal and output it to the signal processing module.

[0095] Furthermore, the signal processing module includes a first operational amplifier OP1, an eighth resistor R8, a ninth resistor R9 and a tenth resistor R10; wherein:

[0096] The inverting terminal of the first operational amplifier OP1 is electrically connected to the output terminal of the second amplifier U2, and the non-inverting terminal of the first operational amplifier OP1 is grounded;

[0097] One end of the eighth resistor R8 is electrically connected to the inverting terminal of the first operational amplifier OP1, and the other end thereof is grounded via the ninth resistor R9;

[0098] One end of the tenth resistor R10 is electrically connected to the inverting terminal of the first operational amplifier OP1, and the other end is electrically connected to the output terminal of the first operational amplifier OP1;

[0099] The output end of the first operational amplifier OP1 is electrically connected to the intelligent control module.

[0100] In this embodiment, the first operational amplifier OP1 may be, but is not limited to, an OP07 operational amplifier, and cooperates with the eighth resistor R8, the ninth resistor R9, and the tenth resistor R10 to form a signal processing module for performing inverting amplification processing on the input signal; the intelligent control module may be, but is not limited to, an MCU processor.

[0101] 1 to 4 , the present invention provides a non-contact current measuring device based on a TMR sensor, which further includes a gain adjustment circuit and a feedback adjustment circuit, wherein:

[0102] The gain adjustment circuit is used to increase the gain of the signal processing module when the single-ended signal input to the signal processing module is less than a preset first gain adjustment threshold or greater than a preset second gain adjustment threshold;

[0103] The feedback adjustment circuit is used to set a feedback coefficient for the signal processing module and adjust the gain of the signal processing module;

[0104] The signal processing module performs inverting amplification processing on the single-ended signal according to the working states of the gain adjustment circuit and the feedback adjustment circuit to obtain a control signal.

[0105] In this embodiment, the TMR sensor module can adopt a TMR sensor circuit, which is composed of four groups of TMR sensors, and measures the magnetic field around the wire in a surrounding manner and converts magnetic energy into electrical energy; the differential processing module can adopt a first amplifier stage circuit, a filter circuit and a second amplifier stage circuit, the first amplifier stage circuit converts the detection signal into a differential current signal, and the filter circuit performs filtering processing, and then the second amplifier stage circuit converts the filtered differential current signal into a single-ended signal; the signal processing module can adopt a signal processing circuit to perform inverse amplification processing on the input single-ended signal and output it; the gain adjustment module can adopt a first amplifier stage circuit, a filter circuit and a second amplifier stage circuit, the first amplifier stage circuit converts the detection signal into a differential current signal, and the filter circuit performs filtering processing, and then the second amplifier stage circuit converts the filtered differential current signal into a single-ended signal. The gain adjustment circuit, composed of a gain adjustment circuit and a second gain adjustment circuit, sets a first gain adjustment threshold and a second gain adjustment threshold respectively, wherein the first gain adjustment threshold is a set negative value and the second gain adjustment threshold is a set positive value, and automatically adjusts the gain effect according to the relationship between the single-ended signal and the first gain adjustment threshold and the second gain adjustment threshold; the feedback adjustment module can adopt a feedback adjustment circuit to provide a feedback coefficient for the signal processing module when the single-ended signal does not reach the adjustment threshold set by the gain adjustment module; the intelligent control module can adopt an intelligent control circuit to receive and analyze the signal output by the signal processing module.

[0106] Further, referring to FIG3 , the gain adjustment circuit includes an eleventh resistor R11, a twelfth resistor R12, a first diode D1, a thirteenth resistor R13, a second operational amplifier OP2, a fourteenth resistor R14, a second diode D2, a fifteenth resistor R15, a sixteenth resistor R16, a threshold setting unit, and a third operational amplifier OP3; wherein:

[0107] One end of the eleventh resistor R11 is electrically connected to the non-grounded end of the ninth resistor R9, and the other end is electrically connected to the cathode of the first diode D1; the anode of the first diode D1 is electrically connected to the output end of the second operational amplifier OP2;

[0108] One end of the twelfth resistor R12 is electrically connected to the output terminal of the second operational amplifier OP2, and the other end is electrically connected to the inverting terminal of the second operational amplifier OP2;

[0109] One end of the thirteenth resistor R13 is electrically connected to the inverting terminal of the second operational amplifier OP2, and the other end is electrically connected to the output terminal of the first operational amplifier OP1;

[0110] One end of the fourteenth resistor R14 is electrically connected to the non-grounded end of the ninth resistor R9, and the other end is electrically connected to the cathode of the second diode D2; the anode of the second diode D2 is electrically connected to the output end of the third operational amplifier OP3;

[0111] One end of the fifteenth resistor R15 is electrically connected to the output terminal of the third operational amplifier OP3, and the other end is electrically connected to the inverting terminal of the third operational amplifier OP3;

[0112] One end of the sixteenth resistor R16 is electrically connected to the inverting terminal of the third operational amplifier OP3, and the other end is electrically connected to the output terminal of the first operational amplifier OP1;

[0113] The threshold setting unit is electrically connected to the non-inverting terminal of the second operational amplifier OP2 and the non-inverting terminal of the third operational amplifier OP3, and is used to set the first feedback threshold as the first gain adjustment threshold and the second feedback threshold as the second gain adjustment threshold; wherein:

[0114] When the single-ended signal input to the signal processing module is less than the first gain adjustment threshold, the second operational amplifier OP2 starts working, thereby increasing the gain of the first operational amplifier OP1; when the single-ended signal input to the signal processing module is greater than the second gain adjustment threshold, the third operational amplifier OP3 starts working, thereby increasing the gain of the first operational amplifier OP1.

[0115] In this embodiment, the second operational amplifier OP2 and the third operational amplifier OP3 may be, but are not limited to, OP07 operational amplifiers.

[0116] Further, referring to FIG4 , the feedback regulation circuit includes a seventeenth resistor R17 , a fourth operational amplifier OP4 , a third diode D3 , a fourth diode D4 , and an eighteenth resistor R18 ; wherein:

[0117] One end of the seventeenth resistor R17 is electrically connected to the non-grounded end of the ninth resistor R9, and the other end is electrically connected to the anode of the third diode D3, the cathode of the fourth diode D4, and the output end of the fourth operational amplifier OP4;

[0118] The cathode of the third diode D3 and the anode of the fourth diode D4 are electrically connected to the inverting terminal of the fourth operational amplifier OP4;

[0119] The non-inverting terminal of the fourth operational amplifier OP4 is grounded;

[0120] One end of the eighteenth resistor R18 is electrically connected to the inverting terminal of the fourth operational amplifier OP4, and the other end is electrically connected to the output terminal of the first operational amplifier OP1; wherein:

[0121] When the single-ended signal input to the signal processing module does not reach the first gain adjustment threshold and the second gain adjustment threshold, the fourth operational amplifier OP4 operates to adjust the gain of the first operational amplifier OP1.

[0122] It should be noted that the present embodiment provides a non-contact current measuring device based on a TMR sensor, which is composed of a first sensor J1, a second sensor J2, a third sensor J3 and a fourth sensor J4 to form a bridge circuit. It measures the magnetic field around the wire in a surrounding manner and converts the magnetic energy into electrical energy, and outputs a differential voltage signal. The differential voltage signal is processed by the first amplifier stage U1 in conjunction with the first resistor R1, the second resistor R2, the third resistor R3, and the fourth resistor R4 and converted into a differential current signal. The differential current signal is filtered by the fifth resistor R5, the sixth resistor R6 and the first capacitor C1, and the filtered differential current signal is converted into a single-ended signal by the second amplifier stage U2 in conjunction with the seventh resistor R7. The single-ended signal is inverted by the first operational amplifier OP1. When the processed signal is less than the set first feedback threshold, that is, the first operational amplifier OP1 is inverted. When the processed signal is greater than the set second feedback threshold, that is, the second gain adjustment threshold, the third op amp OP3 starts working and cooperates with the fourteenth resistor R14, the fifteenth resistor R15, the second diode D2 and the sixteenth resistor R16 to adjust the gain effect of the first op amp OP1. When the processed signal is neither greater than the second feedback threshold nor less than the first feedback threshold, the fourth op amp OP4 starts working and cooperates with the seventeenth resistor R17, the third diode D3, the fourth diode D4 and the eighteenth resistor R18 to adjust the gain effect of the first op amp OP1. Finally, the signal output by the first op amp OP1 will be received and analyzed and processed by the intelligent controller.

[0123] A non-contact current measurement device based on a TMR sensor provided in this embodiment uses a TMR sensor module to measure the magnetic field around a conductor in a surrounding manner, and then performs non-contact current measurement. The differential processing module performs differential amplification, filtering, and conversion processing on the detected signal and outputs a single-ended signal. The single-ended signal is further processed by the signal processing module to improve the detection signal precision and the accuracy of current detection. At the same time, the feedback adjustment circuit sets the feedback coefficient and adjusts the gain of the signal processing module. The gain adjustment circuit automatically adjusts the gain of the signal processing module according to the relationship between the single-ended signal and the set first gain adjustment threshold and second gain adjustment threshold, further improving the signal precision.

[0124] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A non-contact current measuring device based on a TMR sensor, characterized in that: It includes a TMR sensor module, a differential processing module, a signal processing module and an intelligent control module; wherein: The TMR sensor module is used to obtain a detection signal and transmit the detection signal to the differential processing module; The differential processing module is used to perform differential amplification, filtering and conversion processing on the detection signal and output a single-ended signal; The signal processing module is used to perform inverse amplification processing on the single-ended signal to obtain a control signal; The intelligent control module is used to receive control signals and implement control.

2. A non-contact current measuring device based on a TMR sensor according to claim 1, characterized in that: The differential processing module includes a first amplifier circuit, a filter circuit and a second amplifier circuit; wherein: The first amplifier stage circuit is used to perform differential amplification processing on the detection signal to obtain a differential current signal; The filtering circuit is used to filter the differential current signal to obtain a filtered differential current signal; The second amplifier stage circuit is used to convert the filtered differential current signal into a single-ended signal and output it to the signal processing module.

3. A non-contact current measuring device based on a TMR sensor according to claim 2, characterized in that: The TMR sensor module measures the magnetic field around the measured wire in a surrounding manner and converts the magnetic field into an electrical signal to obtain a detection signal; the TMR sensor module includes a first sensor, a second sensor, a third sensor, a fourth sensor and a first power supply; wherein: The first end of the first sensor is electrically connected to the first power supply, the second end of the first sensor is electrically connected to the first end of the third sensor, and the second end of the third sensor is grounded; The first end of the second sensor is electrically connected to the first power supply, the second end of the second sensor is electrically connected to the first end of the fourth sensor, and the second end of the fourth sensor is grounded; The first end of the third sensor and the first end of the fourth sensor are both electrically connected to the first amplifier stage circuit to transmit the detection signal to the differential processing module.

4. A non-contact current measuring device based on a TMR sensor according to claim 3, characterized in that: The first amplifier stage circuit comprises a first resistor, a second resistor, a third resistor, a fourth resistor and a first amplifier; wherein: One end of the first resistor is electrically connected to the TMR sensor module, and the other end is electrically connected to the inverting end of the first amplifier; One end of the second resistor is electrically connected to the TMR sensor module, and the other end is electrically connected to the in-phase end of the first amplifier; One end of the third resistor is electrically connected to the inverting end of the first amplifier, and the other end is electrically connected to the first output end of the first amplifier; One end of the fourth resistor is electrically connected to the in-phase end of the first amplifier, and the other end is electrically connected to the second output end of the first amplifier; The first amplifier stage circuit is electrically connected to the filter circuit via the first amplifier first output terminal and the first amplifier second output terminal.

5. A non-contact current measuring device based on a TMR sensor according to claim 4, characterized in that: The filter circuit comprises a fifth resistor, a sixth resistor and a first capacitor; wherein: One end of the fifth resistor is electrically connected to the first output end of the first amplifier, and the other end is electrically connected to one end of the first capacitor; One end of the sixth resistor is electrically connected to the second output end of the first amplifier, and the other end of the sixth resistor is electrically connected to the other end of the first capacitor; The filter circuit is electrically connected to the second amplifier stage circuit via the first capacitor.

6. A non-contact current measuring device based on a TMR sensor according to claim 5, characterized in that: The second amplifier stage circuit comprises a second amplifier and a seventh resistor; wherein: The in-phase terminal of the second amplifier is electrically connected to one end of the first capacitor, and the inverting terminal of the second amplifier is electrically connected to the other end of the first capacitor; One end of the seventh resistor is electrically connected to the inverting end of the second amplifier, and the other end is electrically connected to the output end of the second amplifier; The second amplifier stage circuit is electrically connected to the signal processing module via the second amplifier output terminal.

7. A non-contact current measuring device based on a TMR sensor according to claim 6, characterized in that: The signal processing module includes a first operational amplifier, an eighth resistor, a ninth resistor and a tenth resistor; in: The inverting terminal of the first operational amplifier is electrically connected to the output terminal of the second amplifier, and the non-inverting terminal of the first operational amplifier is grounded; One end of the eighth resistor is electrically connected to the inverting terminal of the first operational amplifier, and the other end is grounded through the ninth resistor; One end of the tenth resistor is electrically connected to the inverting terminal of the first operational amplifier, and the other end is electrically connected to the output terminal of the first operational amplifier; The first operational amplifier output terminal is electrically connected to the intelligent control module.

8. The non-contact current measuring device based on a TMR sensor according to claim 7, characterized in that: It also includes a gain adjustment circuit and a feedback adjustment circuit, wherein: The gain adjustment circuit is used to increase the gain of the signal processing module when the single-ended signal input to the signal processing module is less than a preset first gain adjustment threshold or greater than a preset second gain adjustment threshold; The feedback adjustment circuit is used to set a feedback coefficient for the signal processing module and adjust the gain of the signal processing module; The signal processing module performs inverting amplification processing on the single-ended signal according to the working states of the gain adjustment circuit and the feedback adjustment circuit to obtain a control signal.

9. The non-contact current measuring device based on a TMR sensor according to claim 8, characterized in that: The gain adjustment circuit includes an eleventh resistor, a twelfth resistor, a first diode, a thirteenth resistor, a second operational amplifier, a fourteenth resistor, a second diode, a fifteenth resistor, a sixteenth resistor, a threshold setting unit and a third operational amplifier; wherein: One end of the eleventh resistor is electrically connected to the non-grounded end of the ninth resistor, and the other end is electrically connected to the cathode of the first diode; the anode of the first diode is electrically connected to the output end of the second operational amplifier; One end of the twelfth resistor is electrically connected to the output end of the second operational amplifier, and the other end is electrically connected to the inverting end of the second operational amplifier; One end of the thirteenth resistor is electrically connected to the inverting terminal of the second operational amplifier, and the other end is electrically connected to the output terminal of the first operational amplifier; One end of the fourteenth resistor is electrically connected to the non-grounded end of the ninth resistor, and the other end is electrically connected to the cathode of the second diode; the anode of the second diode is electrically connected to the output end of the third operational amplifier; One end of the fifteenth resistor is electrically connected to the output end of the third operational amplifier, and the other end is electrically connected to the inverting end of the third operational amplifier; One end of the sixteenth resistor is electrically connected to the inverting terminal of the third operational amplifier, and the other end is electrically connected to the output terminal of the first operational amplifier; The threshold setting unit is electrically connected to the in-phase terminal of the second operational amplifier and the in-phase terminal of the third operational amplifier, and is used to set the first feedback threshold as the first gain adjustment threshold and set the second feedback threshold as the second gain adjustment threshold; wherein: When the single-ended signal input to the signal processing module is less than the first gain adjustment threshold, the second operational amplifier starts working and then increases the gain of the first operational amplifier; when the single-ended signal input to the signal processing module is greater than the second gain adjustment threshold, the third operational amplifier starts working and then increases the gain of the first operational amplifier.

10. The non-contact current measuring device based on a TMR sensor according to claim 8, characterized in that: The feedback regulation circuit includes a seventeenth resistor, a fourth operational amplifier, a third diode, a fourth diode and an eighteenth resistor; wherein: One end of the seventeenth resistor is electrically connected to the non-grounded end of the ninth resistor, and the other end is electrically connected to the anode of the third diode, the cathode of the fourth diode and the output end of the fourth operational amplifier; The cathode of the third diode and the anode of the fourth diode are electrically connected to the inverting terminal of the fourth operational amplifier; The in-phase terminal of the fourth operational amplifier is grounded; One end of the eighteenth resistor is electrically connected to the inverting end of the fourth operational amplifier, and the other end is electrically connected to the output end of the first operational amplifier; wherein: When the single-ended signal input to the signal processing module does not reach the first gain adjustment threshold and the second gain adjustment threshold, the fourth operational amplifier operates to adjust the gain of the first operational amplifier.

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