CN117031103A

CN117031103A - Current sensor

Info

Publication number: CN117031103A
Application number: CN202310801711.8A
Authority: CN
Inventors: 张兴杰; 王冠群
Original assignee: Shenzhen Maikexin Technology Co ltd
Current assignee: Shenzhen Maikexin Technology Co ltd
Priority date: 2023-06-30
Filing date: 2023-06-30
Publication date: 2023-11-10

Abstract

The application discloses a current sensor, which is characterized in that a second coil unit for inducing a voltage U2 of a high-frequency signal is added in a ring-shaped magnetic core, so that a coil L1 in a first coil unit can be designed to have more turns, and when the coil L1 counteracts a magnetic field generated by an electrified conductor, a driving current flowing through the coil L1 does not need to be large, and the power requirement on a power circuit unit can be reduced. And because the coil L2 in the second coil unit has a smaller number of turns, the coil L2 can induce the high-frequency signal to generate an induced voltage, thereby compensating the influence caused by the reduction of the amplitude of the induced high-frequency signal due to the increase of the number of turns of the coil L1.

Description

Current sensor

Technical Field

The application relates to the technical field of electronics, in particular to a current sensor for detecting current in a conductor.

Background

The current sensor is a kind of information which can detect the current to be measured and can convert the detected information into an electric signal meeting the requirement of a certain standard or other information output in a required form according to a certain rule.

The prior art provides a high-broadband high-current sensor for detecting a high-current conductor, which adopts a high-frequency annular magnetic core, a Hall sensor is arranged in the annular magnetic core, and a coil with a certain number of turns is wound on the annular magnetic core. When the large current conductor passes through the annular magnetic core, a magnetic field is generated, the Hall sensor outputs a signal under the action of the magnetic field, and the signal output by the Hall sensor is amplified in amplitude and power and then drives a coil wound on the magnetic core, so that the coil generates a magnetic field with the opposite direction to the magnetic field generated by the conductor to be tested. When the magnetic field generated by the coil and the magnetic field generated by the tested conductor counteract, the voltage generated by the current in the coil flowing through the sampling resistor and the tested conductor current form a certain proportion relation, and the voltage of the sampling resistor can be observed and measured through an oscilloscope or other observation instruments, so that the current flowing through the tested conductor is measured.

In the high-broadband high-current sensor provided in the prior art, a certain power driving is required for the coil in order to cancel the magnetic field generated by the conductor to be measured. If the current of the tested conductor is 100A, the tested conductor passes through the magnetic core and can be seen as one turn, if the number of turns of the coil is 50 turns, the current of the driving coil is theoretically required to reach 2A, and then the operational amplifier of the driving coil or the power amplifier is required to output 2A current. The power supply circuit has certain requirements on power, so that the volume of the current probe is increased, heating is increased, power supply is difficult, and mobile use is not facilitated.

Disclosure of Invention

The embodiment of the application provides a current sensor aiming at the problems that the power requirement of a power circuit of the high-broadband high-current sensor for measuring high current is high, and the current sensor is large in size, increased in heating, difficult in power supply, unfavorable for mobile use and the like.

An embodiment of the present application provides a current sensor including:

the driving unit is connected with the output end of the Hall sensor;

a first coil unit including a coil L1 having N1 turns wound on a toroidal core; the first coil unit further comprises a current input end and a voltage output end, and the current input end is connected with the output end of the driving unit;

a second coil unit including a coil L2 having N2 turns wound on the toroidal core and satisfying N1> N2; the second coil unit is used for inducing a high-frequency magnetic field signal in the annular magnetic core and generating a voltage U2;

the voltage combining unit comprises a first voltage input end and a second voltage input end, wherein the first voltage input end is connected with the voltage output end of the first coil unit and used for receiving voltage U1 output by the first coil unit, and the second voltage input end is connected with the voltage output end of the second coil unit and used for receiving voltage U2 output by the second coil unit; the voltage combining unit is further used for combining the voltages U1 and U2.

When the current sensor provided by the prior art measures the current in a large current conductor, the magnetic field generated by the coil and the magnetic field generated by the conductor can be counteracted due to the fact that a relatively large driving current is needed in the coil, and the current sensor has high requirements on the operational amplifier or the power amplifier of the driving coil, particularly on a power circuit, so that the driving current in the coil is urgently needed to be reduced. In order to reduce the driving current of the coil, the number of turns of the coil needs to be increased to satisfy the cancellation of the magnetic field energy generated by the coil and the magnetic field generated by the conductor. And when the number of turns of the coil is increased, the inventor finds that the more the number of turns of the coil is, the lower the amplitude of the high-frequency signal generated by the large current in the coil-induced conductor is. At this time, the voltage induced in the coil is inaccurate in detection result due to lack of induction of the high-frequency signal.

Therefore, in the current sensor provided by the embodiment of the application, the second coil unit with fewer turns is arranged on the annular magnetic core, and the coil L2 in the second coil unit is sensitive to induction of a high-frequency magnetic field signal generated by a large current of a conductor because the number of turns is smaller than that of the coil L1 in the first coil unit, so that the high-frequency magnetic field signal can be induced and a voltage U2 can be generated. At this time, the coil L1 mainly induces the low-frequency magnetic field signal and generates the voltage U1, the coil L2 mainly induces the high-frequency magnetic field signal and generates the voltage U2, and the obtained detection signal can more accurately reflect the current flowing in the heavy current conductor after the voltage U1 and the voltage U2 are combined. Meanwhile, when the frequency of the current in the conductor is relatively low, the coil L1 plays a main role in detection, and when the frequency of the current in the conductor is relatively high, the coil L2 plays a main role in detection, so that the current sensor provided by the application can be more suitable for the frequency range of the current flowing through the conductor.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present application, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram of a current sensor according to an embodiment of the present application;

FIG. 2 is a schematic diagram of a current sensor according to embodiment 1 of the present application;

fig. 3, fig. 4A, fig. 4B, and fig. 4C are schematic views of a current sensor according to embodiment 2 of the present application;

FIG. 5 is a schematic diagram of a current sensor according to embodiment 3 of the present application;

FIG. 6 is a schematic diagram of an inverting adder according to embodiment 4 of the present application;

FIG. 7 is a schematic diagram of an in-phase adder according to embodiment 4 of the present application;

fig. 8 is a schematic diagram of an in-phase amplifying circuit according to embodiment 5 of the present application;

fig. 9 is a schematic diagram of an inverting amplifier circuit according to embodiment 5 of the present application.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the present application more apparent, the technical solutions of the present application will be clearly and completely described by means of implementation examples with reference to the accompanying drawings in the embodiments of the present application, and it is apparent that the described embodiments are some embodiments of the present application, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.

In the description of the present application, the meaning of a number is one or more, the meaning of a number is two or more, and greater than, less than, exceeding, etc. are understood to exclude the present number, and the meaning of a number is understood to include the present number. The description of the first and second is for the purpose of distinguishing between technical features only and should not be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated or implicitly indicating the precedence of the technical features indicated.

In the description of the present application, unless explicitly defined otherwise, terms such as arrangement and the like should be construed broadly, and those skilled in the art can reasonably determine the specific meaning of the terms in the present application in combination with the specific contents of the technical scheme.

In the description of the present application, a description of the terms "one embodiment," "some embodiments," "an exemplary embodiment," "an example," "a particular example," or "some examples," etc., means that a particular feature or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present application. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

As shown in fig. 1, the current sensor provided by the embodiment of the application comprises an annular magnetic core, a Hall sensor Hall embedded in the annular magnetic core, and a driving unit connected with the output end of the Hall sensor Hall; a first coil unit including a coil L1 having N1 turns wound on a toroidal core; the first coil unit further comprises a current input end and a voltage output end, and the current input end is connected with the output end of the driving unit; a second coil unit including a coil L2 having N2 turns wound on the toroidal core and satisfying N1> N2; the second coil unit is used for inducing a voltage U2 generated by a high-frequency signal in the annular magnetic core; the voltage combining unit comprises a first voltage input end and a second voltage input end, wherein the first voltage input end is connected with the voltage output end of the first coil unit and used for receiving voltage U1 output by the first coil unit, and the second voltage input end is connected with the voltage output end of the second coil unit and used for receiving voltage U2 output by the second coil unit; the voltage combining unit is further used for combining the voltages U1 and U2.

The working principle of the current sensor provided by the embodiment of the application is as follows: passing through the current-carrying conductor L to be measured in the toroidal core _d The energized conductor causes the toroidal core to generate a magnetic field. Hall sensors Hall embedded in the toroidal core generate Hall voltages and output to the drive unit. The driving unit amplifies the amplitude and power of the signal output by the Hall sensor, and outputs driving current to the coil L1 in the first coil unit, when the magnetic field generated by the coil L1 and the energizing conductor L _d When the generated magnetic field counteracts, the coil L1 generates a voltage U1, and the coil L2 in the second coil unit generates a voltage U2 under the induction high-frequency signal, and the voltage combining unit combines the voltage U1 and the voltage U2 and outputs the voltage U2. The first coil unit further comprises a current output end and a resistor R4, wherein the current output end is connected with the first end of the resistor R4 and is connected with a reference voltage or ground after passing through the resistor R4. The current flowing through the coil L1 by the resistor R4 flows out after flowing through the resistor R4, so that a complete current loop is formed, and the first end of the resistor R4 is also connected with the voltage output end of the first coil unit. Optionally, the resistor R4 is an adjustable resistor, and by adjusting the resistance of the resistor R4, the voltage output by the voltage output terminal in the first coil unit can be more stable.

By providing the second coil unit, the number of turns of the coil L2 is smaller than that of the coil L1. For example, coil L1 has 500 turns of N1, e.g. current-carrying conductor L _d If the current flowing in the drive coil L1 is 100A, the current theoretically needs only 0.2A. At this time, since the number of turns of the coil L1 is large, it is insensitive to induction of high frequency signals, which results in a relatively large deviation of the measurement result. By setting the coil L2, for example, setting the number of turns of N2 to 50 turns, the induction of a high-frequency signal is more sensitive than that of the coil L1. Meanwhile, the coil L2 only needs to induce a high-frequency signal to generate voltage, and does not need a power circuit to provide driving current, and the power circuit only needs to provide about 0.2A of driving current of the coil L1The requirements for the power supply circuit are significantly reduced. And greatly reduced the consumption of current sensor, current sensor's volume also can reduce for its removal and use are more convenient.

The current sensor provided by the embodiment of the application can be used for measuring larger current as the requirement of a power circuit can be obviously reduced. As in the current sensor provided according to the prior art, in order to maintain the voltage at which the high frequency signal is sensed, the number of turns of the coil cannot be set too large, resulting in the need for the power supply circuit to supply a larger driving current. The current sensor provided in the prior art, assuming that the number of turns is 50 turns, measures the energizing conductor L with 1 turn _d When the current flowing is 100A, the theoretical driving current needs to reach 2A, but the scheme of the application is only 0.2A, when the current-carrying conductor L _d The current sensor provided by the prior art requires a drive current of 4A, which current sensor cannot be used for measuring anymore, otherwise there is a risk of damage. The driving current in the current sensor provided by the application is only about 0.4A, and the current sensor is not damaged. Therefore, the current sensor provided by the embodiment of the application can measure larger current.

Meanwhile, when the current frequency in the conductor is lower, the coil L1 plays a main role in detection, and when the current frequency in the conductor is higher, the coil L2 plays a main role in detection, so that the current sensor provided by the application can be more suitable for the frequency range of the current flowing through the conductor, and the current sensor provided by the embodiment of the application has the characteristic of high bandwidth and large current.

The current sensor provided by the application has obvious practical effect brought by improvement. For example, the current sensor is typically used with an oscilloscope, and the BNC port of the oscilloscope typically has a power output contact, and if the current sensor consumes a significant amount of power, for example, more than 10W, power cannot be supplied at all through the contact of the oscilloscope because the contact of the oscilloscope does not have such load carrying capability. The current sensor provided by the application can obviously reduce the current of the driving coil, thereby obviously reducing the power consumption of the current sensor, enabling the current sensor to be powered through the contact of the oscilloscope, meeting the load carrying capacity of the oscilloscope and greatly facilitating the use of the current sensor.

Preferably, in the current sensor provided by the embodiment of the application, the annular magnetic core adopts a high-frequency annular magnetic core. In one implementation manner of the driving unit, as shown in fig. 3, 4 and 5, the driving unit comprises a differential amplifier A1 and an operational amplifier A2, two output ends of the hall sensor are respectively connected with a non-inverting input end and an inverting input end of the differential amplifier A1, an output end of the differential amplifier is connected with a non-inverting input end of the operational amplifier A2, an output end of the operational amplifier A2 is connected with a current input end of the first coil unit, and an inverting input end of the operational amplifier A2 is connected with an output end of the operational amplifier A2 through a feedback circuit.

Optionally, the reference signal terminal REF of the differential amplifier A1 may be connected to a degaussing circuit and/or a zeroing circuit for transmitting a degaussing signal and/or a zeroing signal. In one implementation, the reference signal terminal REF of the differential amplifier A1 is connected to an MCU (micro control unit, microcontroller Unit) through a digital-to-analog conversion module. The MCU generates a degaussing signal or a zeroing signal, and the degaussing signal or the zeroing signal is converted into an analog signal through the digital-to-analog conversion module and is transmitted to the differential amplifier A1, so that the residual magnetism of the annular magnetic core is eliminated or the zeroing of the current sensor is realized.

The current sensor provided in this embodiment, as shown in fig. 3, 4 and 5, further includes a protection resistor R1, where one end of the protection resistor is grounded and the other end of the protection resistor is connected to the inverting input end of the operational amplifier A2. Preferably, the filter circuit further comprises a resistor R3 and a capacitor C1, one end of the resistor R3 is connected with the output end of the operational amplifier A2, the other end of the resistor R3 is connected with one end of the capacitor C1, and the other end of the capacitor C1 is grounded. The filter circuit is used to obtain a more stable drive current.

Preferably, the current sensor provided in this embodiment further includes a buffer output module, where the buffer output module includes an operational amplifier A4, an in-phase input end of the operational amplifier A4 is connected to an output signal end of the voltage combining unit, and an output end of the operational amplifier A4 is connected to an inverting input end through a feedback circuit. The output end of the operational amplifier can be externally connected with external equipment, such as an oscilloscope, a spectrum analyzer and the like. The buffer output module buffers the voltage signals output by the voltage merging unit and outputs the buffered voltage signals to external equipment.

16. Preferably, based on the same inventive concept, the current sensor provided in the embodiment of the present application may set a third coil unit according to design requirements, which sets the number of turns of the coil L3 of the third coil unit to N3 and satisfies N2> N3; the third coil unit is used for inducing a magnetic field signal with higher frequency in the annular magnetic core, generating a voltage U3 and sending the voltage U3 to the voltage merging unit;

the voltage combining unit further comprises a third voltage input end, and is used for receiving the voltage U3 output by the third coil unit, and the voltage combining unit is further used for combining the voltages U1, U2 and U3.

Further, a plurality of coil units can be arranged, the plurality of coil units are respectively marked as a first coil unit, a second coil unit and a … … ith coil unit, i is more than or equal to 4, each coil unit comprises a coil wound on an annular magnetic core, and the number of turns of each coil meets N1> N2> … … > Ni; each coil unit is used for respectively inducing magnetic field signals with different frequencies in the annular magnetic core and generating voltages which are respectively marked as U1, U2 and … … Ui, and the voltage combining unit combines and outputs the voltages U1, U2 and … … Ui. . So that the coil L2, the coil L3 … …, the coil Li can induce voltages of signals of different frequencies. Thereby expanding the detection broadband of the current sensor provided by the application.

The voltage merging unit in the embodiment of the application can be realized in a software way, namely in a digital way, and the voltage merging unit realized in a digital way is a digital voltage merging unit; the voltage combining unit provided in this embodiment may also be implemented by an analog voltage combining module formed by combining specific electronic components.

Example 1

The embodiment provides a digital voltage combining module for realizing the voltage combining function in the application. The specific implementation manner of the digital voltage combining module provided in this embodiment is as follows:

as shown in fig. 2, the digital voltage combining module includes a first analog-to-digital conversion subunit, a second analog-to-digital conversion subunit, a combining computation subunit and a digital-to-analog conversion subunit, where an input end of the first analog-to-digital conversion subunit is connected to the first voltage input end, and an output end of the first analog-to-digital conversion subunit is connected to the combining computation subunit, and the first analog-to-digital conversion subunit is used for converting the voltage U1 into a digital signal; the input end of the second analog-to-digital conversion subunit is connected with a second voltage input end, the output end of the second analog-to-digital conversion subunit is connected with the merging calculation subunit, and the second analog-to-digital conversion subunit is used for converting the voltage U2 into a digital signal; the output end of the merging and calculating subunit is connected with the digital-to-analog conversion subunit and is used for merging and calculating the two paths of digital signals and sending the digital signals after merging and calculating to the digital-to-analog conversion subunit, and the digital-to-analog conversion subunit is used for converting the digital signals into analog signals and outputting the analog signals.

The digital voltage combining module provided in this embodiment may be implemented by software. Such as analog-to-digital conversion, combined computation, and digital-to-analog conversion, by a chip programmed with a processing program. On the one hand, the realization mode is more flexible, and on the other hand, the volume of the current sensor can be reduced.

Example 2

The voltage combining unit is realized by an analog voltage combining module, and the embodiment of the application provides an addition circuit.

As shown in fig. 3, in one implementation manner provided in this embodiment, the second coil unit includes a resistor R5, where a first end of the resistor R5 is connected to one end a of the coil L2, and a second end of the resistor R5 may be directly connected to the other end B of the coil L2; the second end of the resistor R5 may also be connected to the other end B of the coil L2 via an intermediate unit. The specific composition of the intermediate element in this embodiment is not limited, and those skilled in the art, based on the technical solution provided in this embodiment, can implement the specific implementation manner of the object of the present embodiment based on the same or similar concept, all of which are within the scope of protection of the present application. When the second coil unit includes the resistor R5, in the current sensor provided in this embodiment, the adding circuit mainly combines the voltage U1 in the first coil unit and the voltage U2 in the second coil unit through the connection relationship between the resistor R4 and the resistor R5. Specifically, a first end of the resistor R4 is connected to a first end of the resistor R5, and a second end of the resistor R5 is connected to an output end. In the addition circuit provided in this embodiment, the low-frequency voltage U1 generated by the first coil unit at the connection end of the connected resistor R4 is added to one end of the coil L2, the voltage connected to the two ends of the coil L2 takes the resistor R5 to sample the voltage U2 generated by the high-frequency magnetic field signal at the two ends of the coil L2, and then the low-frequency voltage U1 output by the first coil unit is superimposed, so as to form a voltage signal with complete frequency component, and the voltage signal is output to an external device through the signal output end or through the buffer output module.

In this embodiment and other embodiments, the coil L1 and the coil L2 may be disposed around the toroidal core by different wires, or may be disposed around the toroidal core by the same wire. And the same wire is wound, so that the assembly process can be simplified to a certain extent. When the same wire is wound, according to the designed turns requirement of the coil L1 and the coil L2, a tap is arranged in the wire for connecting the first end of the resistor R5, and the tap divides the wire into the coil L1 and the coil L2.

In the case of adding the third coil unit and/or the fourth coil unit, the windings of the coils L1, L2, L3, L4 may be wound individually or by one wire, and a tap is provided on the wire to supply power for connection and serve as a distinguishing point of the respective coils. It is also possible that the coil L1 is wound by a separate wire, the coils L2, L3 are wound by one wire, and taps are provided on the wires. Those skilled in the art can implement the present application according to the design requirement of the current sensor in light of the above teachings, and will not be described herein.

As shown in fig. 4A, in a further preferred implementation manner of the addition circuit provided in this embodiment, the addition circuit further includes an operational amplifier A3, a first end of a resistor R4 is connected to one input end of the operational amplifier A3, an output of the operational amplifier A3 is connected to a first end of a resistor R5, specifically, a first end of the resistor R4 is connected to a non-inverting input end of the operational amplifier A3, an inverting input end of the operational amplifier A3 is connected to an output end of the operational amplifier A3, a first end of the resistor R5 is connected to an output end of the operational amplifier A3 and a first end a of a coil L2, respectively, and a second end of the resistor R5 is connected to a second end B of the coil L2 and to a signal output end. The low-frequency voltage U1 generated by the first coil unit at the connecting end of the connected resistor R4 is buffered by the operational amplifier A3 and then is added to one end of the coil L2, the resistor R5 connected to the two ends of the coil L2 samples the voltage U2 generated by the high-frequency signal at the two ends of the coil L2, and the low-frequency voltage U1 output by the operational amplifier A3 is overlapped to form a voltage signal with complete frequency components and is output to external equipment through a signal output end or a buffer output module.

Further, as shown in fig. 4B, in the embodiment of the present application, based on the addition circuit, the first end of R4 may be connected to the non-inverting input end of the operational amplifier A3, the output end of the operational amplifier A3 is connected to the inverting input end via the resistor R6, and the inverting input end of the operational amplifier A3 is connected to the reference voltage or the ground via the resistor R7. Further preferred embodiments of the present application provide that in-phase amplification of the voltage U1 can be achieved.

Preferably, as shown in fig. 4C, in the embodiment of the present application, based on the addition circuit, the first end of the R4 is connected to the inverting input end of the operational amplifier A3 through a resistor R8, and the output end of the operational amplifier A3 is connected to the inverting input end through a resistor R6, and the non-inverting input end of the operational amplifier A3 is connected to the reference voltage or the ground. Further preferred embodiments of the present application provide that an inverting amplification of the voltage U1 can be achieved.

Example 3

As shown in fig. 5, the present embodiment provides another addition circuit to implement an analog voltage combining module.

The adding circuit comprises a capacitor C2, the first end of the second coil unit is grounded, the second end of the second coil unit is connected with the first end of the capacitor C2, and the second end of the capacitor C2 is connected with the voltage output end of the first coil unit and the signal output end. Further, the adding circuit may further include a resistor R5, a first end of the resistor R5 is connected to a second end of the second coil unit, and a second end of the resistor R5 is grounded.

Since the voltage output terminal of the first coil unit is connected to the second coil unit through the capacitor C2. The capacitor C2 may block low frequency signals by high frequency signals. Therefore, the voltage U2 generated by the high-frequency signal induced by the coil L2 can be superimposed to the low-frequency voltage U1 induced by the first coil through the capacitor C2 to form a voltage signal with complete frequency components, and the voltage signal is output to external equipment through a signal output end or a buffer output module.

Example 4

The embodiment provides an adder to realize an analog voltage combining module. The adder may use an inverted adder or an in-phase adder.

As shown IN fig. 6, the inverting adder includes a first input terminal IN1, a resistor R9, a second input terminal IN2, a resistor R10, and an operational amplifier A5, where the first input terminal IN1 is connected to the inverting input terminal of the operational amplifier A5 through the resistor R9 and the second input terminal is connected to the signal output terminal through the resistor R10, the output terminal of the operational amplifier A5 is also connected to the inverting input terminal through the resistor R11, and the non-inverting input terminal of the operational amplifier A5 is connected to a reference voltage; preferably, the non-inverting input terminal of the operational amplifier A5 is connected to a reference voltage through a resistor R12.

The first input end IN1 is connected to the voltage output end of the first coil unit, the second input end IN2 receives a voltage U2 generated by the second coil unit through a high-frequency magnetic field signal induced by the coil L2, and the voltage U2 is output to an external device or to a buffer output module provided by the embodiment of the present application after being superimposed by the operational amplifier A5.

Preferably, IN the solution of providing the third coil unit according to the embodiment of the present application, the inverting adder further includes a third input terminal IN3, where the third input terminal IN3 is connected to the inverting input terminal of the operational amplifier A5 through a resistor R15, and the third input terminal IN3 is configured to receive a voltage U3 generated by a higher-frequency magnetic field signal induced by the third coil unit. The operational amplifier is used for outputting the superimposed voltage U1, voltage U2 and voltage U3 to external equipment or to the buffer output module provided by the embodiment of the application.

As shown IN fig. 7, the IN-phase adder includes a first input terminal IN1, a resistor R9, a second input terminal IN2, a resistor R10, and an operational amplifier A5, where the first input terminal IN1 is connected to the IN-phase input terminal of the operational amplifier A5 through the resistor R9, the second input terminal IN2 is connected to the signal output terminal of the operational amplifier A5 through the resistor R10, the output terminal of the operational amplifier A5 is also connected to the inverting input terminal through the resistor R11, and the inverting input terminal of the operational amplifier A5 is connected to a reference voltage; alternatively, the inverting input terminal of the operational amplifier A5 is connected to the reference voltage through a resistor R12.

Example 5

The buffer output module provided by the embodiment of the application also provides a mode realized by the in-phase amplifying circuit or the anti-phase amplifying circuit.

As shown in fig. 8, the in-phase amplifying circuit includes an operational amplifier A4, a resistor R13 and a resistor R14, wherein the in-phase input end of the operational amplifier A4 is connected to the output end of the voltage combining unit, the inverting input end of the operational amplifier A4 is grounded through the resistor R13, the output end of the operational amplifier A4 outputs a signal to an external device, and the output end of the operational amplifier A4 is connected to the inverting input end through the resistor R14. The inverting amplifier circuit inputs the superimposed voltage at the inverting input terminal, and amplifies a signal outputted to the outside through operational amplification.

As shown in fig. 9, the inverting amplification circuit includes an operational amplifier A4, a resistor R13 and a resistor R14, wherein an inverting input end of the operational amplifier A4 is connected to an output end of the voltage combining unit through the resistor R13, a non-inverting input end of the operational amplifier A4 is grounded, an output end of the operational amplifier A4 outputs a signal to an external device, and an output end of the operational amplifier A4 is connected to the inverting input end through the resistor R14. The in-phase amplifying circuit inputs the superimposed voltage at the in-phase input terminal, and amplifies a signal outputted to the outside through operational amplification.

It will be apparent to those skilled in the art from this disclosure that various other changes and modifications can be made which are within the scope of the application as defined in the appended claims.

Claims

1. A current sensor, comprising:

the driving unit is connected with the output end of the Hall sensor;

the voltage combining unit comprises a first voltage input end and a second voltage input end, wherein the first voltage input end is connected with the voltage output end of the first coil unit and used for receiving voltage U1 output by the first coil unit, and the second voltage input end is connected with the voltage output end of the second coil unit and used for receiving voltage U2 output by the second coil unit; the voltage combining unit is also used for combining and outputting the voltages U1 and U2.

2. The current sensor of claim 1, wherein the voltage combining unit comprises a digital voltage combining module or an analog voltage combining module.

3. The current sensor of claim 2, wherein the digital voltage combining module comprises a first analog-to-digital conversion subunit, a second analog-to-digital conversion subunit, a combining computation subunit and a digital-to-analog conversion subunit, the first analog-to-digital conversion subunit having an input connected to the first voltage input and an output connected to the combining computation subunit, the first analog-to-digital conversion subunit being configured to convert the voltage U1 into a digital signal; the input end of the second analog-to-digital conversion subunit is connected with a second voltage input end, the output end of the second analog-to-digital conversion subunit is connected with a merging calculation subunit, and the second analog-to-digital conversion subunit is used for converting the voltage U2 into a digital signal; the output end of the merging computation subunit is connected with the digital-to-analog conversion subunit, and is used for merging two paths of digital signals, sending the digital signals after merging computation to the digital-to-analog conversion subunit, and converting the digital signals into analog signals and outputting the analog signals.

4. The current sensor of claim 2, wherein the analog voltage combining module comprises an adder or a summing circuit.

5. The current sensor of claim 4, wherein the first coil unit comprises a resistor R4, the resistor R4 having a first end connected to a voltage output of the first coil unit and a second end connected to a reference voltage or a reference ground.

6. The current sensor according to claim 5, wherein the second coil unit includes a resistor R5, a first end of the resistor R5 is connected to one end a of the coil L2, and a second end of the resistor R5 is connected to the other end B of the coil L2; alternatively, the second end of the resistor R5 is connected to the other end B of the coil L2 through an intermediate unit.

7. The current sensor of claim 6, wherein the summing circuit connects a first terminal of resistor R4 to a first terminal of resistor R5 and a second terminal of resistor R5 to an output terminal; or an operational amplifier A3, with a first terminal of a resistor R4 connected to one input terminal of the operational amplifier A3, and an output of the operational amplifier A3 connected to a first terminal of a resistor R5.

8. The current sensor of claim 7, the first end of R4 being connected to the non-inverting input of the operational amplifier A3, the output of the operational amplifier A3 being connected to the inverting input;

or the first end of the R4 is connected to the non-inverting input end of the operational amplifier A3, the output end of the operational amplifier A3 is connected to the inverting input end through a resistor R6, and the inverting input end of the operational amplifier A3 is connected to a reference voltage or ground through a resistor R7;

or the first end of the R4 is connected to the inverting input end of the operational amplifier A3 through a resistor R8, and meanwhile, the output end of the operational amplifier A3 is connected to the inverting input end through a resistor R6, and the non-inverting input end of the operational amplifier A3 is connected with reference voltage or ground.

9. The current sensor of claim 6, wherein: the adding circuit comprises a capacitor C2, the first end of the second coil unit is grounded, the second end of the second coil unit is connected with the first end of the capacitor C2, and the second end of the capacitor C2 is connected with the voltage output end of the first coil unit and the signal output end.

10. The current sensor according to claim 4, wherein the adder comprises an inverting adder, the inverting adder comprises a first input terminal, a resistor R9, a second input terminal, a resistor R10, and an operational amplifier A5, the first input terminal is connected to the inverting input terminal of the operational amplifier A5 through the resistor R9, the second input terminal is connected to the signal output terminal through the resistor R10, the output terminal of the operational amplifier A5 is connected to the inverting input terminal through the resistor R11, and the non-inverting input terminal of the operational amplifier A5 is connected to the reference voltage; or, the non-inverting input end of the operational amplifier A5 is connected with a reference voltage through a resistor R12; the first input end and the second input end are respectively connected with the first voltage input end and the second voltage input end.

11. The current sensor according to claim 4, wherein the adder comprises an in-phase adder, the in-phase adder comprises a first input terminal, a resistor R9, a second input terminal, a resistor R10, and an operational amplifier A5, the first input terminal is connected to the in-phase input terminal of the operational amplifier A5 through the resistor R9, the second input terminal is connected to the signal output terminal through the resistor R10, the output terminal of the operational amplifier A5 is connected to the inverting input terminal through the resistor R11, and the inverting input terminal of the operational amplifier A5 is connected to the reference voltage; alternatively, the inverting input end of the operational amplifier A5 is connected with the reference voltage through a resistor R12; the first input end and the second input end are respectively connected with the first voltage input end and the second voltage input end of the voltage merging unit.

12. The current sensor according to claim 7, wherein the coil L1 in the first coil unit and the coil L2 in the second coil unit are wound by the same wire, and a tap is provided in the wire for connection of the first end of the resistor R5, the tap dividing the wire into the coil L1 and the coil L2.

13. A current sensor according to any one of claims 1 to 12, wherein: the magnetic core also comprises a third coil unit, wherein the third coil unit comprises a coil L3 which is wound on the annular magnetic core and has N3 turns, and N2 is more than N3; the third coil unit is used for inducing a magnetic field signal with higher frequency in the annular magnetic core, generating a voltage U3 and sending the voltage U3 to the voltage merging unit;

the voltage combining unit further comprises a third voltage input end, is used for receiving a voltage U3 output by the third coil unit, and is further used for combining the voltages U1, U2 and U3;

or comprises a plurality of coil units, wherein the plurality of coil units are respectively marked as a first coil unit, a second coil unit and a … … ith coil unit, i is more than or equal to 4, each coil unit comprises a coil wound on an annular magnetic core, and the number of turns of each coil meets N1> N2> … … > Ni; each coil unit is used for respectively inducing magnetic field signals with different frequencies in the annular magnetic core and generating voltages which are respectively marked as U1, U2 and … … Ui, and the voltage combining unit combines and outputs the voltages U1, U2 and … … Ui.

14. A current sensor according to any one of claims 1 to 12, wherein: the driving unit comprises a differential amplifier A1 and a power amplifier A2, wherein two output ends of the Hall sensor are respectively connected with a non-inverting input end and an inverting input end of the differential amplifier A1, an output end of the differential amplifier is connected with a non-inverting input end of an operational amplifier A2, an output end of the operational amplifier A2 is connected with a current input end of the first coil unit, and an inverting input end of the operational amplifier A2 is connected with an output end of the operational amplifier A2 through a feedback circuit.

15. A current sensor according to any one of claims 1 to 12, wherein: the buffer output module comprises an operational amplifier A4, wherein the non-inverting input end of the operational amplifier A4 is connected with the output signal end of the voltage merging unit, the output end of the operational amplifier A4 is connected with the inverting input end through a feedback circuit, and the output end of the operational amplifier A4 outputs signals to external equipment;

or, the buffer output module comprises an in-phase amplifying circuit, the in-phase amplifying circuit comprises an operational amplifier A4, a resistor R13 and a resistor R14, the in-phase input end of the operational amplifier A4 is connected with the output end of the voltage combining unit, the inverting input end of the operational amplifier A4 is grounded through the resistor R13, the output end of the operational amplifier A4 outputs a signal to external equipment, and the output end of the operational amplifier A4 is connected with the inverting input end through the resistor R14;

or, the buffer output module comprises an inverting amplification circuit, the inverting amplification circuit comprises an operational amplifier A4, a resistor R13 and a resistor R14, the inverting input end of the operational amplifier A4 is connected with the output end of the voltage combining unit through the resistor R13, the non-inverting input end of the operational amplifier A4 is grounded, the output end of the operational amplifier A4 outputs a signal to external equipment, and the output end of the operational amplifier A4 is connected with the inverting input end through the resistor R14.