CN212483673U

CN212483673U - Low-power consumption closed-loop Hall current sensor

Info

Publication number: CN212483673U
Application number: CN202020598815.5U
Authority: CN
Inventors: 安云良; 潘海涛; 陈洪梅; 董江华
Original assignee: Beijing Passion Technology Co ltd
Current assignee: Beijing Passion Technology Co ltd
Priority date: 2020-04-20
Filing date: 2020-04-20
Publication date: 2021-02-05
Anticipated expiration: 2030-04-20

Abstract

The utility model discloses a low-power consumption closed loop hall current sensor, including the magnetic core, with the primary side wire of magnetic core cross-under, with the feedback coil of magnetic core wire-wound connection with set up the hall element in the air gap of magnetic core, hall element's output is in proper order through differential amplifier, the switch spare, a drive circuit, ground connection behind feedback coil and the measuring resistance, the switch spare links to each other with microcontroller, microcontroller embeds there is AD converting circuit, AD converting circuit's input connects between feedback coil and measuring resistance, output terminal is connected through the isolator to AD converting circuit's output. The utility model adopts the above structure low-power consumption closed loop hall current sensor, through the switching that adopts microcontroller control analog switch, and then switch on and turn off hall element through the analog switch timesharing for the whole average power control of sensor is at lower level, has realized reducing drive power pipe and load resistance's heat accumulation's purpose, has reduced arranging of fin, has reduced the volume.

Description

Low-power consumption closed-loop Hall current sensor

Technical Field

The utility model relates to a current detection technique especially relates to a low-power consumption closed loop hall current sensor.

Background

Currently in the industrial field there are many situations where the current needs to be measured. The current measurement usually adopts a current sensor based on the hall principle, wherein the current sensor based on the hall principle can be divided into an open-loop hall current sensor and a closed-loop hall current sensor, and the two types of hall current sensors are different in structure and performance. The open-loop Hall current sensor has a simple structure and poor precision; the closed-loop Hall current sensor has excellent linearity and precision and excellent performance due to the existence of the feedback coil, but the closed-loop Hall current sensor is relatively complex in structure.

Fig. 1 is a schematic diagram of a conventional closed-loop hall current sensor, and as shown in fig. 1, when the conventional hall closed-loop current sensor measures a large current, since a magnetic core works in a magnetic balance state (also called a zero-flux state), it can be known from an electromagnetic induction principle that a large secondary compensation current exists in a feedback coil of the sensor; or because the feedback coil has the larger volume of the existing closed-loop Hall sensor, in order to reduce the volume as much as possible, the number of turns of the feedback coil needs to be reduced as much as possible, and at the moment, the current sensor based on the common closed-loop Hall principle can output large secondary compensation current when measuring small current according to the electromagnetic induction principle; the larger secondary compensation current causes the power consumption of a transistor for driving the secondary current, the load resistor and the feedback coil to be larger, so that the sensor is required to have stronger heat dissipation capacity, namely, a heat sink with larger volume is required to be additionally arranged, the process becomes very complicated, the volume is also larger, and the purpose of reducing the volume cannot be achieved.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing a low-power consumption closed loop hall current sensor through the switching that adopts microcontroller control analog switch, and then switches on and turn-off hall element through the analog switch timesharing for the whole average power control of sensor has realized reducing drive power pipe and load resistance's heat accumulation's purpose at lower level, has reduced arranging of fin, has reduced the volume.

In order to achieve the above object, the utility model provides a low-power consumption closed loop hall current sensor, including the magnetic core, with the primary side wire of magnetic core cross-under, with the feedback coil of magnetic core wire-wound connection with set up in hall element in the air gap of magnetic core, hall element's output is ground connection behind differential amplifier, switching part, drive circuit, feedback coil and measuring resistance in proper order, switching part links to each other with microcontroller, microcontroller embeds there is AD converting circuit, AD converting circuit's input connect in feedback coil with between the measuring resistance, output terminal is connected through the isolator to AD converting circuit's output.

Preferably, the hall element comprises one hall element or at least two hall elements connected in parallel, and the hall element is an indium antimonide hall element.

Preferably, the switch member includes one analog switch or at least two analog switches connected in parallel, and the analog switch is a normally-closed switch.

Preferably, the driving circuit comprises at least one pair of triodes or field effect transistors.

Preferably, the microcontroller, the switch, the differential amplifier, the driving circuit, the measuring resistor and the output terminal are all integrated on a circuit board, and the circuit board and the magnetic core are all encapsulated inside the housing through resin.

Preferably, the housing includes a housing and a cover fastened to an end of the housing.

Preferably, the material of the magnetic core is low remanence soft magnetic.

Preferably, the measuring resistor is a power type measuring resistor.

Therefore, the utility model discloses an adopt low-power consumption closed loop hall current sensor of above-mentioned structure, through the switching that adopts microcontroller control analog switch, and then switch on and turn off hall element through the analog switch timesharing, make the whole average power control of sensor at lower level, realized reducing drive power pipe and load resistance's heat accumulation's purpose, the long-term steady operation under the condition of less compensating coil number of turns or great secondary compensating current of fin heat dissipation that need not the heaviness, thereby realized that the heavy current measurement need not the purpose of fin.

The technical solution of the present invention is further described in detail by the accompanying drawings and examples.

Drawings

FIG. 1 is a schematic diagram of a prior art closed loop Hall current sensor;

fig. 2 is a schematic diagram of a low-power consumption closed-loop hall current sensor according to an embodiment of the present invention;

fig. 3 is a structural diagram of a low-power consumption closed-loop hall current sensor according to an embodiment of the present invention.

Wherein: 1. a primary side wire; 2. a magnetic core; 3. a feedback coil; 4. a Hall element; 5. a differential amplifier; 6. a switch member; 7. a drive circuit; 8. measuring the resistance; 9. a housing; 10. a circuit board; 11. an output terminal; 12. and (7) buckling a cover.

Detailed Description

The present invention will be further described with reference to the accompanying drawings, and it should be noted that the present embodiment is based on the technical solution, and the detailed embodiments and the specific operation processes are provided, but the protection scope of the present invention is not limited to the present embodiment.

Fig. 2 is the schematic diagram of a low-power consumption closed-loop hall current sensor according to an embodiment of the present invention, fig. 3 is the structure diagram of a low-power consumption closed-loop hall current sensor according to an embodiment of the present invention, as shown in fig. 2 and fig. 3, the present invention provides a structure for achieving the above object, which comprises a magnetic core 2, a primary side wire 1 crossing the magnetic core 2, a feedback coil 3 winding around the magnetic core 2, and a hall element 4 disposed in an air gap of the magnetic core 2, wherein an output end of the hall element 4 is grounded after passing through a differential amplifier 5, a switch element 6, a driving circuit 7, the feedback coil 3, and a measuring resistor 8 in sequence, wherein the material of the magnetic core 2 is soft magnetic; the measuring resistor 8 is a power type measuring resistor 8; the Hall element 4 comprises a Hall element or at least two Hall elements connected in parallel, and the Hall element is an indium antimonide Hall element; the switch member 6 includes an analog switch or at least two analog switches connected in parallel, the analog switch is a normally-closed switch, that is, the analog switch 2001 is in an off state in a default state; the driving circuit 7 includes at least one pair of transistors or fets. Microcontroller, switch member 6, differential amplifier 5, drive circuit 7, measuring resistor 8 and output terminal 11 are all integrated on circuit board 10, circuit board 10 and magnetic core 2 are all encapsulated inside the shell through the resin, the shell includes casing 9 and buckle closure 12 in casing 9 tip, switch member 6 links to each other with microcontroller, microcontroller embeds there is AD converting circuit, AD converting circuit's input connects between feedback coil 3 and measuring resistor 8, output terminal 11 is connected through the isolator to AD converting circuit's output, output terminal 11 of this embodiment can be through RS485 communication interface and export digital signal to the display screen with MODBUS digital protocol form.

The working principle is as follows:

during measurement, firstly, the analog switch Is controlled by the microcontroller to be conducted, a primary current Ip Is conducted in a primary lead wire 1, a magnetic field generated by the current Is gathered in the magnetic core 2 according to the electromagnetic induction principle, a Hall element arranged in an air gap of the magnetic core 2 senses the magnetic field B, the Hall element outputs a differential voltage signal VH, the differential voltage signal VH Is respectively input to a positive input end and a negative input end of the differential amplifier 5 and then sequentially outputs a secondary current Is through the conducted analog switch and the driving circuit 7, the secondary current Is generates a magnetic field which Is the same as the magnetic field B in magnitude and opposite in direction after passing through the feedback coil 3, so that the magnetic induction intensity in the magnetic core 2 Is kept to be zero, at the moment, the magnitude of the primary current Ip can be calculated according to the turn ratio by collecting the voltage drop at the measuring resistor 8 through the AD conversion circuit, and the calculated value Is output, and the calculation part of the calculation part, therefore, it is not described herein; and most of the time, because the analog switch is in an off state, the average output current in a period of time is very small, so that the heat productivity of the feedback coil 3, the driving circuit 7 and the measuring resistor 8 is very low, and the power consumption and the heat productivity are reduced.

Therefore, the utility model discloses an adopt low-power consumption closed loop hall current sensor of above-mentioned structure, through the switching that adopts microcontroller control analog switch, and then switch on and turn off hall element through the analog switch timesharing for the whole average power control of sensor has realized reducing drive power pipe and load resistance's heat accumulation's purpose at lower level, has reduced arranging of fin, has reduced the volume.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting the same, and although the present invention is described in detail with reference to the preferred embodiments, those skilled in the art should understand that: the technical solution of the present invention can still be modified or replaced by other equivalent means, and the modified technical solution can not be separated from the spirit and scope of the technical solution of the present invention.

Claims

1. A low-power consumption closed-loop Hall current sensor comprises a magnetic core, a primary side wire connected with the magnetic core in a penetrating way, a feedback coil wound with the magnetic core and a Hall element arranged in an air gap of the magnetic core, and is characterized in that: the output end of the Hall element is grounded after sequentially passing through a differential amplifier, a switching piece, a driving circuit, a feedback coil and a measuring resistor, the switching piece is connected with a microcontroller, an AD conversion circuit is arranged in the microcontroller, the input end of the AD conversion circuit is connected between the feedback coil and the measuring resistor, and the output end of the AD conversion circuit is connected with an output terminal through an isolator.

2. The low-power consumption closed-loop hall current sensor according to claim 1, wherein: the Hall element comprises a Hall piece or at least two Hall pieces connected in parallel, and the Hall piece is an indium antimonide Hall piece.

3. The low-power consumption closed-loop hall current sensor according to claim 1, wherein: the switch part comprises an analog switch or at least two analog switches connected in parallel, and the analog switches are normally closed switches.

4. The low-power consumption closed-loop hall current sensor according to claim 1, wherein: the driving circuit comprises at least one pair of triodes or field effect transistors.

5. The low-power consumption closed-loop hall current sensor according to claim 1, wherein: the microcontroller, the switch piece, the differential amplifier, the drive circuit, the measuring resistor and the output terminal are all integrated on a circuit board, and the circuit board and the magnetic core are all packaged in the shell through resin.

6. The low-power consumption closed-loop Hall current sensor according to claim 5, wherein: the shell comprises a shell body and a buckle cover buckled at the end part of the shell body.

7. The low-power consumption closed-loop hall current sensor according to claim 1, wherein: the magnetic core is made of soft magnetic with low remanence.

8. The low-power consumption closed-loop hall current sensor according to claim 1, wherein: the measuring resistor is a power type measuring resistor.