CN213633577U

CN213633577U - High dynamic range alternating current/direct current isolation measuring circuit for measuring instrument

Info

Publication number: CN213633577U
Application number: CN202022524078.7U
Authority: CN
Inventors: 宋晓峰; 蔡磊; 关建国; 胡心祥; 梁巧华; 卢少标
Original assignee: Hanhua Intelligent Technology Foshan Co ltd
Current assignee: Hanhua Intelligent Technology Foshan Co ltd
Priority date: 2020-11-04
Filing date: 2020-11-04
Publication date: 2021-07-06
Anticipated expiration: 2030-11-04

Abstract

The utility model belongs to the electronic field and discloses a high dynamic range alternating/direct current isolated measuring circuit for a measuring instrument, which comprises a PCB circuit board and a Hall sensor; the circuit comprises a PCB and is characterized in that a circuit loop is arranged on one surface of the PCB, the Hall sensor is arranged on the other surface of the PCB, and the Hall sensor and the circuit loop are arranged oppositely. The circuit has low cost and can test the current which is more than 20 times of rated current of the Hall sensor.

Description

High dynamic range alternating current/direct current isolation measuring circuit for measuring instrument

Technical Field

The utility model relates to an electron field specifically is a high dynamic range exchanges/direct current's isolation measurement circuit for measuring instrument.

Background

The current currently applied to power measurement mainly includes three types of current methods for measuring ac current:

1. a current transformer using electromagnetic coupling effect is provided, but the transformer is provided with a metal magnetic core, so that when the input current reaches more than 10 times of the rated current, the transformer is saturated and cannot be accurately measured. The measuring method has the advantages of high measuring precision, and can realize electrical isolation by adopting electromagnetic isolation input and output. The disadvantage is that the overcurrent exceeding the rated current of the current transformer by more than 10 times cannot be measured.

2. The second one is to use an electronic transformer, which is essentially a hall sensor with a magnetic core and uses the hall effect to isolate and measure current, but the element also has the problem of easy saturation and higher cost.

3. The third one is to use manganese copper resistance, which is a copper alloy, and can pass large current, but the disadvantage is also obvious, because the voltage drop generated when the manganese copper resistance flows current is directly used to detect current, the power supply and the isolation device which are independently supplied with power from outside are used to realize electrical isolation for realizing isolation measurement, thus increasing cost and product volume, and being not suitable for small space.

Therefore, the technical problem to be solved by the scheme is as follows: how to develop a set of circuit applicable to the detection of high-rate overcurrent at low cost.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a measuring instrument is with high dynamic range AC/DC current's isolation measurement circuit, this circuit with low costs, testable 20 times more than the hall sensor rated current.

In order to achieve the above object, the utility model provides a following technical scheme:

a high dynamic range alternating current/direct current isolation measuring circuit for a measuring instrument comprises a PCB circuit board and a Hall sensor; the circuit comprises a PCB and is characterized in that a circuit loop is arranged on one surface of the PCB, the Hall sensor is arranged on the other surface of the PCB, and the Hall sensor and the circuit loop are arranged oppositely.

In the isolated measuring circuit of high dynamic range alternating current/direct current for the measuring instrument, a current transformer is connected in series on the circuit loop.

In the high dynamic range alternating current/direct current isolation measuring circuit for the measuring instrument, the PCB is of a single-layer or multi-layer structure.

In the above-mentioned high dynamic range ac/dc current isolated measuring circuit for a measuring instrument, the circuit loop is a copper foil circuit printed on a PCB circuit board.

In the isolation measurement circuit for high dynamic range alternating current/direct current for the measurement instrument, the position of the circuit loop, which is opposite to the hall sensor, is a necking structure, and the distance between two lines of the necking structure is smaller than the distance between two lines of other positions on the circuit loop.

In the high dynamic range alternating/direct current isolation measuring circuit for the measuring instrument, the PCB is provided with two terminals, and the two terminals are electrically connected with two ends of the circuit loop.

In the high dynamic range alternating current/direct current isolation measuring circuit for the measuring instrument, the current transformer and the hall sensor are arranged on the same side of the PCB or on two sides of the PCB.

The utility model has the advantages of as follows and beneficial effect:

according to the scheme, the Hall sensor and the circuit loop are respectively arranged on two sides of the PCB, the current does not pass through the Hall sensor, an external magnetic field formed at the position of the Hall sensor acts on an internal sensing circuit of the Hall sensor, and isolation measurement of the current is realized.

More specifically, the chip-type hall sensor (reference chip ACS712) using direct current input is operated in a manner that current isolation measurement is performed by a magnetic field formed by current flowing through a pin of the chip-type hall sensor, but the pin has limited current carrying capacity and cannot pass large current due to direct current input.

The current does not directly flow through the Hall sensor but flows through the reverse side of the circuit board welded with the Hall sensor, an insulating circuit board is arranged in the middle of the circuit board, the electrical isolation capability of the detection circuit is improved, meanwhile, the detected intensity of the magnetic field constructed by the external current is smaller than the magnetic field intensity formed by the current directly flowing through the Hall sensor, so that the detection range of the magnetic field detection circuit on the current can be greatly expanded, and the mode is equivalent to weakening the sensitivity of a chip on the magnetic field detection, and the measurement accuracy is reduced when the signal is small. The solution to this problem is to connect a current transformer in series in the measured current loop, and to measure a small current by using the current transformer, when the current exceeds the measurement range of the current transformer, the hall sensor can ensure the measurement capability of the large current part, thereby realizing the measurement capability within the range of 20 times of the rated current.

Drawings

Fig. 1 is a front view of embodiment 1 of the present invention.

Fig. 2 is a front view of embodiment 1 of the present invention.

Detailed Description

The technical solution of the present invention will be further described in detail with reference to the following detailed description, but the present invention is not limited thereto.

Example 1

Referring to fig. 1 and 2, an isolated measuring circuit of high dynamic range alternating/direct current for a measuring instrument comprises a PCB circuit board 1, a hall sensor 3; a circuit loop 2 is arranged on one side of the PCB 1, the Hall sensor 3 is arranged on the other side of the PCB 1, and the Hall sensor 3 and the circuit loop 2 are arranged just opposite to each other.

The hall sensor 3 is also called an electronic transformer, the electronic transformer is essentially the hall sensor 3 with a magnetic core, and the hall effect is adopted to isolate and measure the current.

According to the scheme, the Hall sensor 3 and the circuit loop 2 are respectively arranged on two sides of the PCB 1, the current does not pass through the Hall sensor 3, an external magnetic field formed at the position of the Hall sensor 3 acts on an internal sensing circuit of the Hall sensor 3, and isolation measurement of the current is realized.

More specifically, the chip-type hall sensor 3 (refer to the chip ACS712) with a current directly input function is used, the chip-type hall element operates on the principle that current isolation measurement is performed through a magnetic field formed by current flowing through a pin of the chip, but the current directly input function is current carrying capacity of the pin is limited, and large current cannot pass through the pin.

Because the current does not flow through the Hall sensor 3 directly but flows through the reverse side of the circuit board welded with the Hall sensor 3, an insulating circuit board is arranged in the middle, the electrical isolation capability of the detection circuit is increased, and meanwhile, because the magnetic field constructed by the external current has the detected intensity smaller than the magnetic field intensity formed by the current flowing through the Hall sensor 3 directly, the detection range of the current can be greatly expanded, and the mode is equivalent to weakening the sensitivity of the chip to the magnetic field detection, so that the measurement precision is reduced when the signal is small.

The solution to this problem is to connect a current transformer 4 in series in the measured current loop, specifically, the current transformer 4 is connected in series on the circuit loop 2, the current transformer 4 is used to measure a small current, and when the current exceeds the measurement range of the current transformer 4, the hall sensor 3 can ensure the measurement capability of the large current part, thereby realizing the measurement capability within the range of 20 times of the rated current.

Generally, the rated current of the Hall sensor is 20A at most, and the rated current of the current transformer is generally less than 10A.

In the present embodiment, the PCB circuit board 1 has a single-layer or multi-layer structure, preferably a multi-layer structure.

As a further preferred embodiment, the circuit 2 is a copper foil circuit printed on the PCB circuit board 1.

In order to improve the magnetic field intensity of a local area and increase the amplitude of an output signal of the hall chip, the position of the circuit loop 2, which is opposite to the hall sensor 3, is provided with a necking structure 5, and the distance between two lines of the necking structure 5 is smaller than the distance between two lines of other positions on the circuit loop 2.

Preferably, the PCB circuit board 1 is provided with two terminals 6, and the two terminals 6 are electrically connected to two ends of the circuit loop 2. The current transformer 4 and the hall sensor 3 are arranged at the same side of the PCB circuit board 1 or at two sides of the PCB circuit board 1, specifically referring to fig. 1, the current transformer 4 and the hall sensor 3 are arranged at the same side of the PCB circuit board 1, referring to fig. 2, the current transformer 4 and the hall sensor 3 are arranged at the front and back sides of the PCB circuit board 1.

The current transformer 4 is provided with a pin A and a pin B.

The specific dc current flow direction of this embodiment is: current enters from one terminal 6, passes through the current loop 2, passes through pin a, passes through pin B, passes through the current loop 2, and is output from the other terminal 6.

In the case of an alternating current, the current is periodically changed, and the forward and reverse flowing directions of the direct current can be referred to.

The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be equivalent replacement modes, and all are included in the scope of the present invention.

Claims

1. A high dynamic range alternating current/direct current isolation measuring circuit for a measuring instrument comprises a PCB circuit board and a Hall sensor; the circuit is characterized in that a circuit loop is arranged on one surface of the PCB, the Hall sensor is arranged on the other surface of the PCB, and the Hall sensor and the circuit loop are arranged in a right-to-right mode.

2. The high dynamic range ac/dc isolated measurement circuit for a meter of claim 1, wherein: and a current transformer is connected in series on the circuit loop.

3. The high dynamic range ac/dc isolated measurement circuit for a meter of claim 1, wherein: the PCB circuit board is of a single-layer or multi-layer structure.

4. The high dynamic range ac/dc isolated measurement circuit for a meter of claim 1, wherein: the circuit loop is a copper foil circuit printed on a PCB circuit board.

5. The isolated measuring circuit of high dynamic range AC/DC current for measuring instrument according to any one of claims 1-4, wherein: the circuit loop is of a necking structure at a position opposite to the Hall sensor, and the distance between two lines of the necking structure is smaller than the distance between two lines of other positions on the circuit loop.

6. The isolated measuring circuit of high dynamic range AC/DC current for measuring instrument according to any one of claims 1-4, wherein: the PCB circuit board is provided with two terminals, and the two terminals are electrically connected with two ends of the circuit loop.

7. The high dynamic range ac/dc isolated measurement circuit for a measurement instrument of claim 2, wherein: the current transformer and the Hall sensor are arranged on the same side of the PCB or on two sides of the PCB.