A TMR electronic current transformer

Abstract

This utility model discloses a TMR electronic current transformer, including a TMR sensing head and a data acquisition device. The TMR sensing head includes a printed circuit board and a TMR chip, a temperature chip, and corresponding power supply and conditioning circuits disposed on the printed circuit board. A through-hole is provided in the center of the printed circuit board for the power system busbar under test to pass through. The TMR sensing head uses a single-chip, dual-chip, or ring array TMR chip. The TMR chip is used to sense the measured current value, and the temperature chip is used to sense the ambient temperature value. Both the TMR chip and the temperature chip are electrically connected to the data acquisition device. The TMR electronic current transformer provided by this utility model measures the power system busbar current based on the TMR chip, and has a series of advantages such as non-contact measurement, simultaneous AC and DC measurement, frequency up to the MHz level, small delay, large dynamic measurement range, low cost, high insulation level, small size, and high precision.

Description

Technical Field

[0001] This utility model relates to the field of current transformer technology, and in particular to a TMR electronic current transformer. Background Technology

[0002] Current transformers are crucial devices for power system energy metering and protection, and are broadly classified into non-isolated and isolated types. Non-isolated current transformers generally employ the shunt principle and can measure AC / DC and wideband signals; however, they are intrusive measurements that can disrupt the existing power system, limiting their application. Isolated current transformers are typically based on Rogowski coils and iron-core coils. This principle cannot measure DC currents, the iron core is prone to saturation under high currents, and they are bulky, making them unsuitable for the measurement requirements of next-generation intelligent power systems. Utility Model Content

[0003] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0004] A TMR electronic current transformer includes a TMR sensing head and a data acquisition device;

[0005] The TMR sensor head includes a printed circuit board and a TMR chip, a temperature chip, and corresponding power supply circuits and conditioning circuits disposed on the printed circuit board.

[0006] The printed circuit board has a through hole in the middle for the busbar of the power system under test to pass through;

[0007] The TMR sensor head uses a single-chip, dual-chip, or ring array TMR chip.

[0008] The TMR chip is used to sense the measured current value, and the temperature chip is used to sense the ambient temperature value.

[0009] Both the TMR chip and the temperature chip are electrically connected to the acquisition device.

[0010] In some embodiments, the acquisition device includes an analog-to-digital converter, a processor, a memory, and corresponding power supply circuits and peripheral circuits;

[0011] The analog-to-digital converter is used to convert the analog signals collected by the TMR chip and the temperature chip into digital signals;

[0012] The processor is electrically connected to the analog-to-digital converter and the memory respectively. The memory stores compensation parameters in advance. The processor is used to perform compensation calibration and output the compensated and calibrated data.

[0013] In some embodiments, a soldering area is provided on each side of the through hole on the printed circuit board;

[0014] When a single TMR chip is used in the TMR sensor head, only one TMR chip is soldered in one of the soldering areas.

[0015] When dual TMR chips are used in the TMR sensor head, one TMR chip is soldered in each of the two soldering areas.

[0016] The temperature chip, power supply circuit, and conditioning circuit are located on the printed circuit board at a position away from the through-hole relative to the soldering area.

[0017] In some embodiments, when an array of TMR chips is used in the TMR sensor head, multiple TMR chips are distributed in a ring array on the printed circuit board around the via.

[0018] The temperature chip, power supply circuit, and conditioning circuit are located on the printed circuit board at a position away from the through-hole relative to the soldering area.

[0019] In some embodiments, the TMR chip has a push-pull Wheatstone full-bridge structure and contains four unshielded high-sensitivity TMR sensor elements.

[0020] Compared with the prior art, the TMR electronic current transformer provided by this utility model measures the bus current of the power system based on the tunnel magnetoresistive (TMR) chip. It has a series of advantages such as non-contact measurement, simultaneous AC and DC measurement, frequency up to MHz level, small delay, large dynamic measurement range, low cost, high insulation level, small size, and high precision. Attached Figure Description

[0021] Figure 1 A schematic diagram of the TMR electronic current transformer provided by this utility model;

[0022] Figure 2 A schematic diagram of a TMR sensor head using a single or dual TMR chip;

[0023] Figure 3 This is a schematic diagram of a TMR sensor head that uses an array of TMR chips. Detailed Implementation

[0024] To make the technical means, creative features, objectives and effects of this utility model easier to understand, the following describes how this utility model is implemented in conjunction with specific embodiments.

[0025] Reference Figure 1As shown, this utility model provides a TMR electronic current transformer, including a TMR sensing head 1 and a data acquisition device 2. The TMR sensing head 1 includes a printed circuit board 10 and a TMR chip 11, a temperature chip 12, and corresponding power supply circuits and conditioning circuits disposed on the printed circuit board 10. A through hole 13 is provided in the middle of the printed circuit board 10 for the busbar of the power system under test to pass through. The TMR sensing head 1 uses a single chip, a dual chip, or a ring array of TMR chips 11. The TMR chip 11 is used to sense the measured current value, and the temperature chip 12 is used to sense the ambient temperature value. Both the TMR chip 11 and the temperature chip 12 are electrically connected to the data acquisition device 2.

[0026] Furthermore, the acquisition device 2 includes an analog-to-digital converter 21, a processor 22, a memory 23, and corresponding power supply circuits and peripheral circuits; the analog-to-digital converter 21 is used to convert the analog signals acquired by the TMR chip 11 and the temperature chip 12 into digital signals; the processor 22 is electrically connected to the analog-to-digital converter 21 and the memory 23 respectively, the memory 23 is pre-stored with compensation parameters, the processor 22 is used to perform compensation calibration, and output the compensated and calibrated data.

[0027] The working principle of the TMR electronic current transformer provided by this utility model is as follows: (Refer to...) Figure 1 As shown, it can be understood that the TMR chip 11 is used to sense the measured current value Ip and convert it into a voltage signal V_TMR, the temperature chip 12 is used to sense the ambient temperature value and convert it into a voltage signal V_TEMP, and both voltage signals V_TMR and V_TEMP are transmitted to the analog-to-digital converter 21; the analog-to-digital converter 21 is used to convert the voltage signals V_TMR and V_TEMP into digital signals TMR_AD and TEMP_AD, respectively; the memory 23 stores compensation parameters in advance; the processor 22 is used to perform compensation calibration according to the digital signals TMR_AD, TEMP_AD and compensation parameters, and output the compensated and calibrated data TMR_OUT.

[0028] During compensation calibration, it can be implemented based on existing compensation algorithms. For example, a compensation table between temperature and current measurement values ​​and actual current values ​​can be established in advance through experiments, and the corresponding compensation parameters can be input into memory 23 for storage. Subsequently, compensation calibration can be completed directly based on the current temperature and current measurement values ​​by looking up the table.

[0029] Reference Figure 2As shown, in the first embodiment, when a TMR sensor head 1 using a single or dual TMR chip 11 is employed, a soldering area 14 is provided on each side of the through hole on the printed circuit board 10; when a single TMR chip 11 is used in the TMR sensor head 1, only one TMR chip 11 is soldered in one of the soldering areas 14; when dual TMR chips 11 are used in the TMR sensor head 1, one TMR chip 11 is soldered in each of the two soldering areas 14; the temperature chip 12, the power supply circuit, and the conditioning circuit are located on the printed circuit board 10 at a position away from the through hole 13 relative to the soldering area 14.

[0030] Reference Figure 3 As shown, in the second embodiment, when an array of TMR chips 11 is used in the TMR sensor head 1, multiple TMR chips 11 are distributed in a ring array on the printed circuit board 10 around the through hole 13; the temperature chip 12, power supply circuit and conditioning circuit are located on the printed circuit board 10 at a position away from the through hole 13 relative to the soldering area 14.

[0031] Furthermore, the TMR chip 11 can be internally designed as a push-pull Wheatstone full-bridge structure, containing four unshielded, high-sensitivity TMR sensor elements capable of sensing the magnitude of an external magnetic field. When the external magnetic field changes, its output voltage changes proportionally. The temperature chip 12 is positioned near the TMR chip 11 to sense the ambient temperature. The TMR chip 11 can be an existing multidimensional TMR2151 or TMR2102 chip; the temperature chip 12 can be an existing LM20BIM7 temperature sensor. Of course, other models of the TMR chip 11 and temperature chip 12 can also be selected according to actual needs.

[0032] In summary, the TMR electronic current transformer provided by this utility model measures the bus current of the power system based on the TMR chip, and has a series of advantages such as non-contact measurement, simultaneous AC and DC measurement, frequency up to MHz level, small delay, large dynamic measurement range, low cost, high insulation level, small size, and high precision.

[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model and are not intended to limit it. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this utility model without departing from the spirit and scope of the technical solutions of this utility model, and all such modifications or substitutions should be covered within the scope of the claims of this utility model.

Claims

1. A TMR electronic current transformer, characterized in that, Includes a TMR sensor head (1) and a data acquisition device (2); The TMR sensor head (1) includes a printed circuit board (10) and a TMR chip (11), a temperature chip (12) and corresponding power supply circuit and conditioning circuit disposed on the printed circuit board (10); The printed circuit board (10) has a through hole (13) in the middle for the busbar of the power system under test to pass through. The TMR sensor head (1) uses a single-chip, dual-chip, or ring array TMR chip (11). The TMR chip (11) is used to sense the measured current value, and the temperature chip (12) is used to sense the ambient temperature value. The TMR chip (11) and the temperature chip (12) are both electrically connected to the acquisition device (2).

2. The TMR electronic current transformer according to claim 1, characterized in that, The acquisition device (2) includes an analog-to-digital converter (21), a processor (22), a memory (23), and corresponding power supply circuits and peripheral circuits; The analog-to-digital converter (21) is used to convert the analog signals collected by the TMR chip (11) and the temperature chip (12) into digital signals; The processor (22) is electrically connected to the analog-to-digital converter (21) and the memory (23) respectively. The memory (23) stores compensation parameters in advance. The processor (22) is used to perform compensation calibration and output the data after compensation calibration.

3. The TMR electronic current transformer according to claim 1, characterized in that, On the printed circuit board (10), a soldering area (14) is provided on each side of the through hole. When a single TMR chip (11) is used in the TMR sensor head (1), only one TMR chip (11) is soldered in one of the soldering areas (14). When the TMR sensor head (1) uses dual TMR chips (11), one TMR chip (11) is soldered in each of the two soldering areas (14). The temperature chip (12), power supply circuit and conditioning circuit are located on the printed circuit board (10) at a position away from the through hole (13) relative to the soldering area (14).

4. The TMR electronic current transformer according to claim 1, characterized in that, When an array of TMR chips (11) is used in the TMR sensor head (1), multiple TMR chips (11) are arranged in a ring array on the printed circuit board (10) around the through hole (13). The temperature chip (12), power supply circuit and conditioning circuit are located on the printed circuit board (10) at a position away from the through hole (13) relative to the soldering area (14).

5. The TMR electronic current transformer according to claim 1, characterized in that, The TMR chip (11) has a push-pull Wheatstone full-bridge structure and contains four unshielded high-sensitivity TMR sensor elements.

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