High-precision double-range current sensor

Abstract

The utility model relates to the technical field of sensors, in particular to a high-precision double-range current sensor, a closed-loop circuit comprises a self-checking coil SC and a sampling resistor Rm, the self-checking coil SC is used for generating an excitation signal, the excitation signal is converted into an output signal through the closed-loop circuit, and the sampling resistor Rm is connected with the self-checking coil SC. The sampling resistor Rm is used for providing sampling current for the large-current range circuit and the small-current range circuit, and the large-current range circuit is connected to the two ends of the sampling resistor Rm in series; compared with a conventional sensor, according to the scheme, double-path output is adopted, a measured current wire penetrates through the sensor, the functions of amplification and signal conditioning of currents of different ranges are achieved through two paths of operational amplifiers, an external auxiliary circuit is matched, and therefore the function of high-precision double-range current measurement is flexibly achieved; according to the scheme, the current sensor adopts a closed-loop scheme to improve the signal-to-noise ratio and the detection precision, and is very suitable for occasions of high-precision current detection in a power electronic system.

Description

Technical Field

[0001] This utility model relates to the field of sensor technology, and in particular to a high-precision dual-range current sensor. Background Technology

[0002] Traditional single-range sensors can only measure one range of current, offering limited functionality, a limited current measurement range, and low measurement accuracy, making them unsuitable for applications requiring dual-range current measurement. Alternatively, two current sensors can be used to measure different current ranges, but this increases size and cost, and adds inconvenience to use.

[0003] Traditional dual-range sensors typically employ an open-loop design, which, compared to a closed-loop design, has a poorer signal-to-noise ratio and lower detection accuracy, failing to meet the demands of high-precision detection. Summary of the Invention

[0004] The main objective of this invention is to provide a high-precision dual-range current sensor to solve the problems of poor signal-to-noise ratio, low detection accuracy, and inability to meet the requirements of high-precision detection in related technologies.

[0005] To achieve the above objectives, according to one aspect of the present invention, a high-precision dual-range current sensor is provided, comprising: a closed-loop circuit, the closed-loop circuit including a self-test coil SC and a sampling resistor Rm, the self-test coil SC being used to generate an excitation signal, the excitation signal being converted into an output signal by the closed-loop circuit, and the sampling resistor Rm being used to provide sampling current for a large current range circuit and a small current range circuit.

[0006] A high-current range circuit is connected in series across the sampling resistor Rm, and the high-current range circuit is used to sample and amplify the sampling resistor Rm.

[0007] The small current range circuit is connected in series across the sampling resistor Rm, and the small current range circuit samples and amplifies the sampling resistor Rm.

[0008] Furthermore, the closed-loop circuit also includes a magnetic core PQ, a feedback coil FBC, a sensitive component sensor, an operational amplifier UC, and a push-pull amplifier PPA. The self-test coil SC is wound around the magnetic core PQ, with one end of the self-test coil SC grounded and the other end connected to the check point CHK. The feedback coil FBC is wound around the magnetic core PQ.

[0009] Furthermore, one end of the feedback coil FBC is connected to the collector (C) of the push-pull amplifier PPA, and the other end is connected to one end of the sampling resistor Rm. The other end of the sampling resistor Rm is connected to the base (B) of the push-pull amplifier PPA. The negative input terminal (-Vee) of the operational amplifier UC is connected to the emitter (E) of the push-pull amplifier PPA, and the positive input terminal (+Vcc) of the operational amplifier UC is connected to the EN interface of the sensitive component sensor.

[0010] Furthermore, the high current range circuit includes an operational amplifier UB, resistors RB1, RB2, RB3, and RB4. The positive input terminal (+Vcc) of the operational amplifier UB is connected to one end of the sampling resistor Rm, and the negative input terminal (-Vee) of the operational amplifier UB is connected to the other end of the sampling resistor Rm. One end of the resistor RB4 is connected to the negative input terminal (-Vee) of the operational amplifier UB, and the other end is connected to the OUT terminal of the operational amplifier UB. The OUT terminal of the operational amplifier UB is used to output the amplified signal.

[0011] Furthermore, resistor RB1 is connected in series between the positive input terminal (+Vcc) of operational amplifier UB and the sampling resistor Rm, resistor RB2 is connected in series between the negative input terminal (-Vee) of operational amplifier UB and the sampling resistor Rm, and one end of resistor RB3 is connected to the positive input terminal (+Vcc) of operational amplifier UB, and the other end is connected to the voltage source Vref, which provides a reference voltage for the high current range circuit.

[0012] Furthermore, the small current range circuit includes an operational amplifier UA, a resistor group, and a capacitor group. The resistor group includes resistors RA1, RA2, RA3, and RA4. The capacitor group includes capacitors CA1 and CA2. Resistor RA1 and capacitor CA1 are connected in series between the positive input terminal (+Vcc) of operational amplifier UA and the sampling resistor Rm. Resistor RA2 and capacitor CA2 are connected in series between the negative input terminal (-Vee) of operational amplifier UA and the sampling resistor Rm.

[0013] Furthermore, one end of resistor RA3 is connected to the positive input terminal (+Vcc) of operational amplifier UA, and the other end is connected to voltage source Vref, which provides a reference voltage for the small current range circuit. One end of resistor RA4 is connected to the negative input terminal (-Vee) of operational amplifier UA, and the other end is connected to the OUT terminal of operational amplifier UA, which is used to output the amplified signal.

[0014] Compared with the prior art, this utility model has the following advantages: Compared with conventional sensors, this solution adopts dual output, the current being measured is passed through the sensor, and two operational amplifiers realize the functions of amplification and signal conditioning of currents with different ranges. Matching external auxiliary circuits, it can flexibly realize the function of high-precision dual-range current measurement. The current sensor of this solution adopts a closed-loop scheme to improve the signal-to-noise ratio and detection accuracy, which is very suitable for high-precision current detection in power electronic systems. Attached Figure Description

[0015] Figure 1 This is the circuit diagram of this utility model. Detailed Implementation

[0016] To further illustrate the technical means and effects adopted by this utility model in order to achieve the intended utility model purpose, the following detailed description of the specific implementation methods, structure, features and effects of this utility model is provided in conjunction with the accompanying drawings and preferred embodiments.

[0017] Please see Figure 1 This embodiment provides a high-precision dual-range current sensor, including: a closed-loop circuit, the closed-loop circuit including a self-test coil SC and a sampling resistor Rm, the self-test coil SC is used to generate an excitation signal, the excitation signal is converted into an output signal through the closed-loop circuit, and the sampling resistor Rm is used to provide sampling current for the large current range circuit and the small current range circuit.

[0018] The self-test coil SC generates an excitation signal, and the frequency and amplitude of this excitation signal can be flexibly set according to the system detection needs. The excitation signal is converted into an output signal through the magnetic core PQ, feedback coil FBC, sensitive component sensor, operational amplifier UC, push-pull amplifier PPA, and sampling resistor Rm, thereby determining the system's operating status and providing system reliability.

[0019] The high current range circuit is connected in series across the sampling resistor Rm. The high current range circuit is used to sample and amplify the sampling resistor Rm to realize the detection of a large range current.

[0020] The small current range circuit is connected in series across the sampling resistor Rm. The small current range circuit samples and amplifies the sampling resistor Rm to realize the detection of small current range.

[0021] The closed-loop circuit also includes a magnetic core PQ, a feedback coil FBC, a sensitive component sensor, an operational amplifier UC, and a push-pull amplifier PPA. The self-test coil SC is wound around the magnetic core PQ, with one end of the self-test coil SC grounded and the other end connected to the check point CHK. The feedback coil FBC is wound around the magnetic core PQ.

[0022] One end of the feedback coil FBC is connected to the collector (C) of the push-pull amplifier PPA, and the other end is connected to one end of the sampling resistor Rm. The other end of the sampling resistor Rm is connected to the base (B) of the push-pull amplifier PPA. The negative input terminal (-Vee) of the operational amplifier UC is connected to the emitter (E) of the push-pull amplifier PPA, and the positive input terminal (+Vcc) of the operational amplifier UC is connected to the EN interface of the sensitive component sensor.

[0023] The high current range circuit includes an operational amplifier UB, resistors RB1, RB2, RB3, and RB4. The positive input terminal (+Vcc) of the operational amplifier UB is connected to one end of the sampling resistor Rm, and the negative input terminal (-Vee) of the operational amplifier UB is connected to the other end of the sampling resistor Rm. One end of the resistor RB4 is connected to the negative input terminal (-Vee) of the operational amplifier UB, and the other end is connected to the OUT terminal of the operational amplifier UB. The OUT terminal of the operational amplifier UB is used to output the amplified signal.

[0024] Resistor RB1 is connected in series between the positive input terminal (+Vcc) of operational amplifier UB and the sampling resistor Rm. Resistor RB2 is connected in series between the negative input terminal (-Vee) of operational amplifier UB and the sampling resistor Rm. One end of resistor RB3 is connected to the positive input terminal (+Vcc) of operational amplifier UB, and the other end is connected to the voltage source Vref, which provides a reference voltage for the high current range circuit.

[0025] The small current range circuit includes an operational amplifier UA, a resistor group, and a capacitor group. The resistor group includes resistors RA1, RA2, RA3, and RA4. The capacitor group includes capacitors CA1 and CA2. Resistor RA1 and capacitor CA1 are connected in series between the positive input terminal (+Vcc) of operational amplifier UA and the sampling resistor Rm. Resistor RA2 and capacitor CA2 are connected in series between the negative input terminal (-Vee) of operational amplifier UA and the sampling resistor Rm.

[0026] One end of resistor RA3 is connected to the positive input terminal (+Vcc) of operational amplifier UA, and the other end is connected to the voltage source Vref. The voltage source Vref provides a reference voltage for the small current range circuit. One end of resistor RA4 is connected to the negative input terminal (-Vee) of operational amplifier UA, and the other end is connected to the OUT terminal of operational amplifier UA. The OUT terminal of operational amplifier UA is used to output the amplified signal.

[0027] This device features dual outputs, enabling high-precision measurement across both large and small current ranges, and is widely applicable.

[0028] This sensor employs a closed-loop design to improve detection accuracy and signal-to-noise ratio. The closed-loop design consists of a magnetic core, feedback coil, sensing components, operational amplifiers, and push-pull amplifiers. The large-range output operational amplifier UB samples and amplifies the sampling resistor Rm to detect a large-range current; the small-range output operational amplifier UA samples, biases, and amplifies the sampling resistor Rm to detect a small-range current. Furthermore, different operational amplifier resistance values ​​allow for adjustment of the amplification factor.

[0029] The sensor itself has a self-testing function. The self-testing coil generates an excitation signal, and the signal is converted into an output signal through a closed-loop system, which is used to judge the system's working status, provide the system's reliability, and has a compact structure and high detection accuracy. It meets various needs for measuring currents of different sizes, and its shape can also be flexibly designed according to the system being tested.

[0030] The sensitive components in a sensor include, but are not limited to, Hall, AMR, GMR, TMR, etc. The current that can be detected by a large current range includes, but is not limited to, DC, AC, and pulsating current, while the current that can be detected by a small current range includes, but is not limited to, AC and arcing current.

[0031] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Although the present utility model has been disclosed above with reference to a preferred embodiment, it is not intended to limit the present utility model. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present utility model. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present utility model without departing from the scope of the present utility model shall still fall within the scope of the present utility model.

Claims

1. A high-precision dual-range current sensor, characterized in that, include: A closed-loop circuit, comprising a self-test coil SC and a sampling resistor Rm, wherein the self-test coil SC is used to generate an excitation signal, the excitation signal is converted into an output signal by the closed-loop circuit, and the sampling resistor Rm is used to provide sampling current for the large current range circuit and the small current range circuit. A high-current range circuit is connected in series across the sampling resistor Rm, and the high-current range circuit is used to sample and amplify the sampling resistor Rm. The small current range circuit is connected in series across the sampling resistor Rm, and the small current range circuit samples and amplifies the sampling resistor Rm.

2. The high-precision dual-range current sensor according to claim 1, characterized in that, The closed-loop circuit also includes a magnetic core PQ, a feedback coil FBC, a sensitive component sensor, an operational amplifier UC, and a push-pull amplifier PPA. The self-test coil SC is wound around the magnetic core PQ, with one end of the self-test coil SC grounded and the other end connected to the check point CHK. The feedback coil FBC is wound around the magnetic core PQ.

3. The high-precision dual-range current sensor according to claim 2, characterized in that, One end of the feedback coil FBC is connected to the collector of the push-pull amplifier PPA, and the other end is connected to one end of the sampling resistor Rm. The other end of the sampling resistor Rm is connected to the base of the push-pull amplifier PPA. The negative input terminal of the operational amplifier UC is connected to the emitter of the push-pull amplifier PPA, and the positive input terminal of the operational amplifier UC is connected to the EN interface of the sensitive component sensor.

4. The high-precision dual-range current sensor according to claim 1, characterized in that, The high current range circuit includes an operational amplifier UB, resistors RB1, RB2, RB3, and RB4. The positive input terminal of the operational amplifier UB is connected to one end of the sampling resistor Rm, and the negative input terminal of the operational amplifier UB is connected to the other end of the sampling resistor Rm. One end of the resistor RB4 is connected to the negative input terminal of the operational amplifier UB, and the other end is connected to the OUT terminal of the operational amplifier UB. The OUT terminal of the operational amplifier UB is used to output the amplified signal.

5. The high-precision dual-range current sensor according to claim 4, characterized in that, The resistor RB1 is connected in series between the positive input terminal of the operational amplifier UB and the sampling resistor Rm. The resistor RB2 is connected in series between the negative input terminal of the operational amplifier UB and the sampling resistor Rm. One end of the resistor RB3 is connected to the positive input terminal of the operational amplifier UB, and the other end is connected to the voltage source Vref, which provides a reference voltage for the high current range circuit.

6. The high-precision dual-range current sensor according to claim 1, characterized in that, The small current range circuit includes an operational amplifier UA, a resistor group, and a capacitor group. The resistor group includes resistors RA1, RA2, RA3, and RA4. The capacitor group includes capacitors CA1 and CA2. Resistor RA1 and capacitor CA1 are connected in series between the positive input terminal of operational amplifier UA and the sampling resistor Rm. Resistor RA2 and capacitor CA2 are connected in series between the negative input terminal of operational amplifier UA and the sampling resistor Rm.

7. The high-precision dual-range current sensor according to claim 6, characterized in that, One end of resistor RA3 is connected to the positive input terminal of operational amplifier UA, and the other end is connected to voltage source Vref. Voltage source Vref provides a reference voltage for small current range circuit. One end of resistor RA4 is connected to the negative input terminal of operational amplifier UA, and the other end is connected to the OUT terminal of operational amplifier UA. The OUT terminal of operational amplifier UA is used to output the amplified signal.

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