CN213041920U

CN213041920U - Single-phase intelligent electric energy meter adopting PCB type current sensor for metering

Info

Publication number: CN213041920U
Application number: CN202021207491.4U
Authority: CN
Inventors: 崔婷婷; 张健; 王海宝; 王峥; 庞振江; 郭彦
Original assignee: Beijing Banner Electric Manufacturing Corp; Beijing Smartchip Microelectronics Technology Co Ltd
Current assignee: Beijing Banner Electric Manufacturing Corp; Beijing Smartchip Microelectronics Technology Co Ltd
Priority date: 2020-06-25
Filing date: 2020-06-25
Publication date: 2021-04-23
Anticipated expiration: 2030-06-25

Abstract

The utility model discloses a single-phase intelligent electric energy meter which adopts a PCB type current sensor to measure, wherein the PCB type current sensor is used for replacing a traditional current transformer to sample the current of the intelligent electric energy meter, and the current value is calculated through a corresponding formula; meanwhile, the correction method is used for temperature compensation, so that the current sensor accurately samples current and is free from the influence of a direct current component. The beneficial effects of the utility model are that, simple structure, low cost can carry out compatible assembly better with the electric energy meter mainboard.

Description

Single-phase intelligent electric energy meter adopting PCB type current sensor for metering

Technical Field

The utility model relates to a current metering field of electric energy meter, especially an adopt single-phase intelligent electric energy meter of PCB formula current sensor measurement.

Background

The electric energy metering is one of the most important functions in the intelligent electric energy meter, and the accurate sampling of voltage and current directly influences the metering accuracy.

At present, in most single-phase intelligent electric energy meter designs, a zero line current loop realizes sampling by using a current transformer, the current transformer is provided with an iron core, direct current components existing in current cannot be transmitted and changed between the transformer and a secondary transformer, all the direct current components are used as exciting current, the increase of the exciting current leads to magnetic saturation of the transformer, and further causes overlarge sampling current error; meanwhile, the current transformer also has the defects of complex insulation structure, large volume, high cost and the like.

SUMMERY OF THE UTILITY MODEL

The utility model aims at solving the problem, a single-phase intelligent electric energy meter that adopts PCB formula current sensor measurement has been designed.

The technical scheme of the utility model is that, a single-phase intelligent electric energy meter using PCB type current sensor for metering comprises a single-phase intelligent electric energy meter and a PCB type current sensor, characterized in that, the PCB type current sensor is fixedly installed on a zero line connecting terminal of the single-phase intelligent electric energy meter, the differential voltage signal output end of the PCB type current sensor is connected to a zero line current metering loop on a main board of the single-phase intelligent electric energy meter, the voltage signal of the PCB type current sensor is sent to a metering chip current sampling channel of the single-phase intelligent electric energy meter after passing through a resistance-capacitance anti-aliasing circuit on the main board of the single-phase intelligent electric energy meter, and is input into a metering chip of the single-phase intelligent electric energy meter after AD conversion, the metering chip calculates the input voltage and then stores the input voltage into a current register of the metering chip for subsequent current effective value calculation, a power supply interface of the PCB type current sensor is connected with a metering, and connecting the ground wire interface of the current sensor with a ground loop of a metering part circuit of the electric energy meter.

The alternating current measuring range of the PCB type current sensor is 0-150A.

The signal sensitivity of the PCB type current sensor is 13.33mV/A, namely when 1A current flows through the sensor, the output voltage signal is 13.33 mV.

The PCB type current sensor is a SCT6101M module provided by Beijing Intelligence core micro corporation.

The PCB type current sensor is fixedly installed on the 3 rd and 4 th terminals of the main terminal of the single-phase intelligent electric energy meter at the primary side through screws.

The power supply of the PCB type current sensor adopts a power supply mode shared with the metering chip, and is a direct current 5V power supply.

The differential voltage signal output end of the PCB type current sensor is connected to a zero line current metering loop on a main board of the single-phase intelligent electric energy meter, and connectors between the PCB type current sensor and the main board of the electric energy meter are connected through a group of flat cables.

The current effective value is calculated in the following mode:

a. firstly, the current value needs to be adjusted, and the standard meter is loaded on the rated currents Ib and Ib of the electric energy meter_RMSWhen the rated current loaded on the electric energy meter by the standard meter reaches Ib, the metering chip calculates the reading of the current register after AD conversion, and a ratio coefficient K can be obtained according to the following formula:

K＝Ib/Ib_RMS

b. when the electric energy meter measures current, the current can be measured through I-K I_RMSThe input current value I is obtained.

When the current is large, the compensation correction method for the current value is as follows:

a. and (3) loading the current Imax of the electric energy meter by the standard meter, calculating a current value I according to a formula in the step 5, obtaining a difference value e between the current value I and the standard value Imax, and calculating a correction coefficient I:

i＝e/Imax

i takes a 3-bit decimal number;

b. the corrected value I (corrected) at each current point affected by temperature is I/(1+ I).

And the power supply of the metering part circuit is a direct current 5V power supply.

Advantageous effects

Utilize the utility model discloses an adopt single-phase intelligent ammeter of PCB formula current sensor measurement of technical scheme preparation, it includes the advantage as follows:

1. the method uses the current sensor to sample current, and because the current sensor does not have iron core materials, the sampling precision is not influenced when direct current components exist in alternating current signals, so that the problem of magnetic saturation of the iron core of the current transformer caused by the direct current components is well solved;

2. the method adopts the PCB type current sensor, the size of the PCB type current sensor is smaller, the interference with a main board of the electric energy meter is reduced, and meanwhile, more space is provided for the layout of the main board;

3. the PCB type current sensor has simple structure and low price, and greatly saves the cost;

4. temperature compensation is adopted in current sampling, so that the sampling precision is more accurate.

Drawings

Fig. 1 is a measurement schematic diagram of a single-phase intelligent electric energy meter according to the present invention, which is measured by using a PCB type current sensor;

fig. 2 is a circuit diagram of the PCB type current sensor connected to the single-phase intelligent electric energy meter.

Detailed Description

The following specifically describes the present invention with reference to the accompanying drawings, and as shown in fig. 1-2, the present application is characterized in that the current transformer on the single-phase intelligent electric energy meter is removed, and then the PCB type current sensor is fixedly mounted on the zero line terminal of the single-phase intelligent electric energy meter; the power supply of the PCB type current sensor adopts a power supply mode shared with a metering chip, and the mode is as follows: connecting a power supply interface of the PCB type current sensor with a power supply of a metering part circuit of the electric energy meter, and connecting a ground wire interface of the current sensor with a ground loop of the metering part circuit of the electric energy meter so as to ensure that the whole metering loop has no influence caused by a power supply level difference; connecting a differential voltage signal output end of the PCB type current sensor to a zero line current metering loop on a main board of the single-phase intelligent electric energy meter; voltage signals of the PCB type current sensor are sent to a current sampling channel of a metering chip after passing through a resistance-capacitance anti-aliasing circuit, are subjected to AD conversion, are further calculated by the metering chip and are stored in a current register of the metering chip for calculating the effective value and power of subsequent current;

in the technical scheme of the application, the current effective value is calculated in the following mode:

K＝Ib/Ib_RMS

b. when the electric energy meter measures current, the current can be measured through I-K I_RMSObtaining the current value I of the current input;

in addition, when the sampling current of the electric energy meter is large, the internal circuit temperature of the current sensor is high, which affects the signal sensitivity S of the current sensor to deviate from 13.33mV/a, and further makes the calculated current value inaccurate, so that the current value needs to be compensated and corrected when the current is large, and the correction method is as follows:

i＝e/Imax

i takes a 3-bit decimal number;

In the implementation process of the technical scheme, a person in the art needs to connect all the electrical components in the present application with a power supply adapted to the electrical components through a wire, and should select an appropriate controller according to actual conditions to meet control requirements, and specific connection and control sequence.

In the technical scheme, the specific implementation process comprises the following steps:

1. the utility model discloses the current sensor is SCT6101M module that Beijing intelligence core micro corporation provided, the primary side is fixedly installed on the 3 rd and 4 th terminals of the main terminal of the single-phase intelligent electric energy meter by screws;

2. the power supply of the current sensor is direct current 5V, and a power supply mode shared with the metering chip is adopted, so that a power supply interface and a ground wire interface of the current sensor are respectively connected with a 5V power supply and a ground loop of a metering part circuit of the electric energy meter, and the influence caused by a power supply level difference value does not exist in the whole metering loop;

3. the differential voltage signal output end of the current sensor is connected to a zero line current metering loop on a main board of the single-phase intelligent electric energy meter; each connecting port between the current sensor and the electric energy meter main board is connected through a group of flat cables;

4. when current flows through the electric energy meter, for example, the current applied by the electric energy meter is 5A, the current flowing through the primary side of the sensor is 5A;

5. through the conversion of an internal circuit of the current sensor, the secondary side outputs a corresponding tiny voltage signal U; the current sensor signal sensitivity is 13.33mV/A, and when the sensor current is 5A, the differential voltage signal output by the secondary side is 66.65 mV;

6. the voltage signal is sent to a current sampling channel of the metering chip after passing through a resistance-capacitance anti-aliasing circuit, is further calculated by AD conversion and is stored in a current register of the metering chip, and when the input current is 5A, the value of the read current register is 0230AE (hexadecimal) and is used for calculating the effective value and power of the subsequent current;

7. calculating a current value;

7-1, firstly, the current value needs to be adjusted, the rated current Ib loaded on the electric energy meter by the standard meter is 5A, and the corresponding register value Ib_RMS0230AE, the coefficient of the ratio K is 5/0230 AE;

7-2, when the electric energy meter measures the current, obtaining the value of the input current according to the ratio coefficient and the current register value, namely I (5/0230AE) I_RMSObtaining the current value of the current input;

8. when the sampling current of the electric energy meter is larger, the temperature of an internal circuit of the current sensor is higher, so that the signal sensitivity S of the current sensor is influenced to deviate from 13.33mV/A, and the calculated current value is further inaccurate, so that the current value needs to be compensated and corrected when the current is larger;

8-1, the current Imax of the electric energy meter loaded by the standard meter is 60A, the current value I is 60.921A according to the formula in the step 7, the difference e between the current value I and the standard value Imax is 0.921A, and the correction coefficient I is calculated:

i＝e/Imax＝0.921/60＝0.015

i takes a 3-bit decimal number;

8-2, when the electric energy meter is loaded with a larger current value for a long time, and the obtained current value is 45.705A, the corrected value I (corrected) is I/(1+ I) 45.705A/(1 +0.015) 45.03A, so that the influence of temperature on sampling precision can be compensated;

it is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation. The use of the phrase "comprising one of the elements does not exclude the presence of other like elements in the process, method, article, or apparatus that comprises the element.

Above-mentioned technical scheme has only embodied the utility model discloses technical scheme's preferred technical scheme, some changes that this technical field's technical personnel probably made to some parts wherein have all embodied the utility model discloses a principle belongs to within the protection scope of the utility model.

Claims

1. A single-phase intelligent electric energy meter adopting a PCB type current sensor for metering comprises the single-phase intelligent electric energy meter and the PCB type current sensor, and is characterized in that the PCB type current sensor is fixedly arranged on a zero line connecting terminal of the single-phase intelligent electric energy meter, a differential voltage signal output end of the PCB type current sensor is connected to a zero line current metering loop on a main board of the single-phase intelligent electric energy meter, a voltage signal of the PCB type current sensor is sent into a metering chip current sampling channel of the single-phase intelligent electric energy meter after passing through a resistance-capacitance anti-aliasing circuit on the main board of the single-phase intelligent electric energy meter, is input into a metering chip of the single-phase intelligent electric energy meter after being subjected to AD conversion, is stored into a current register of the metering chip after being subjected to input voltage calculation for subsequent current effective value calculation, and a power supply interface of the PCB type current sensor is connected with, and connecting the ground wire interface of the current sensor with a ground loop of a metering part circuit of the electric energy meter.

2. The single-phase intelligent electric energy meter metered by the PCB type current sensor as recited in claim 1, wherein the AC current measuring range of the PCB type current sensor is 0-150A.

3. The single-phase intelligent electric energy meter measured by the PCB type current sensor as recited in claim 1, wherein the signal sensitivity of the PCB type current sensor is 13.33mV/A, namely when 1A current flows through the sensor, the output voltage signal is 13.33 mV.

4. The single-phase intelligent electric energy meter measured by the PCB type current sensor as claimed in claim 1, wherein the PCB type current sensor is SCT6101M module provided by Beijing Intelligent core micro corporation.

5. The single-phase intelligent electric energy meter measured by the PCB type current sensor as claimed in claim 4, wherein the PCB type current sensor is fixedly arranged on the 3 rd and 4 th terminals of the main terminal of the single-phase intelligent electric energy meter at the primary side through screws.

6. The single-phase intelligent electric energy meter measured by the PCB type current sensor as claimed in claim 1, wherein the power supply of the PCB type current sensor is a common power supply mode with the measuring chip, and the power supply is a direct current 5V power supply.

7. The single-phase intelligent electric energy meter measured by the PCB type current sensor as claimed in claim 1, wherein each connecting port between the PCB type current sensor and the electric energy meter main board is connected by a group of flat cables.

8. The single-phase intelligent electric energy meter measured by the PCB type current sensor as claimed in claim 1, wherein the circuit power supply of the measuring part is a direct current 5V power supply.