阅读说明：本技术 单相智能电能表采用pcb式电流传感器计量的方法 (Method for single-phase intelligent electric energy meter to measure by adopting PCB type current sensor ) 是由 崔婷婷 张健 王海宝 王峥 庞振江 郭彦 于 2020-06-25 设计创作，主要内容包括：本发明公开了一种单相智能电能表采用PCB式电流传感器计量的方法,该方法运用PCB式电流传感器代替传统的电流互感器进行智能电能表电流采样,当电能表计量电流时,电流传感器将电流转换为满足计量芯片采样通道的小电压信号,计量芯片AD转换进一步得到寄存器值,最终通过转换公式得出电流值；同时,在采样电流较大电流传感器灵敏度受温度影响时,运用矫正方法来进行温度补偿,使得电流传感器精确采样电流且免受直流分量影响。本发明的有益效果是,结构简单,成本低廉,可更好与电能表主板进行兼容装配。(The invention discloses a method for metering a single-phase intelligent electric energy meter by adopting a PCB (printed circuit board) type current sensor, which is characterized in that the PCB type current sensor is used for replacing a traditional current transformer to sample the current of the intelligent electric energy meter, when the electric energy meter meters the current, the current sensor converts the current into a small voltage signal meeting a sampling channel of a metering chip, the metering chip is subjected to AD (analog-to-digital) conversion to further obtain a register value, and finally, a current value is obtained through a conversion formula; meanwhile, when the sensitivity of the current sensor with larger sampling current is influenced by temperature, a correction method is applied to carry out temperature compensation, so that the current sensor accurately samples the current and is not influenced by a direct-current component. The invention has the advantages of simple structure, low cost and better compatibility assembly with the electric energy meter mainboard.)

1. A method for metering a single-phase intelligent electric energy meter by adopting a PCB type current sensor is characterized by comprising the following steps:

step 1, fixedly mounting a PCB type current sensor on a zero line wiring terminal of a single-phase intelligent electric energy meter;

step 2, the power supply of the PCB type current sensor adopts a power supply sharing mode with the 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;

step 3, 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;

step 4, sending a voltage signal of the PCB type current sensor into a current sampling channel of a metering chip after passing through a resistance-capacitance anti-aliasing circuit, performing AD conversion, further calculating by the metering chip, and storing the voltage signal into a current register of the metering chip for calculating a subsequent current effective value and power;

step 5, the way of calculating the current effective value in step 4 is:

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 current register reading is calculated by the metering chip after AD conversion, and the 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_RMSObtaining the current value I of the current input;

step 6, when the sampling current of the electric energy meter is large, the temperature of an internal circuit of the current sensor is high, 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 large, and the correction mode 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).

2. The method for the single-phase intelligent electric energy meter to measure by the PCB type current sensor according to claim 1, wherein when current flows through the electric energy meter, zero line current flows through the primary side of the sensor, and the alternating current measuring range of the current sensor is 0-150A due to the limitation of the overcurrent area.

3. The method for the single-phase intelligent electric energy meter to measure by the PCB type current sensor according to claim 1, wherein the secondary side outputs a corresponding tiny voltage signal U through the conversion of an internal circuit of the current sensor; wherein, the current sensor signal sensitivity is 13.33mV/A, that is, when 1A current flows through the sensor, the output voltage signal is 13.33 mV.

4. The method for metering by using the PCB type current sensor of the single-phase intelligent electric energy meter according to claim 1, wherein the PCB type current sensor is an SCT6101M module provided by Beijing Intelligent core micro corporation.

5. The method for metering by using the PCB type current sensor for the single-phase intelligent electric energy meter according to 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 by screws.

6. The method for metering by using the PCB type current sensor of the single-phase intelligent electric energy meter according to claim 1, wherein the power supply of the PCB type current sensor is a power supply shared with the metering chip, and the power supply is a direct current 5V power supply.

7. The method for metering by using the PCB type current sensor of the single-phase intelligent electric energy meter according to claim 1, wherein 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, and each connecting port between the PCB type current sensor and the main board of the electric energy meter is connected by a group of flat cables.

Technical Field

The invention relates to the field of current measurement of electric energy meters, in particular to a method for measuring by adopting a PCB (printed circuit board) type current sensor for a single-phase intelligent electric energy meter.

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 transformed between the transformer and a secondary current, and all the direct current components are used as exciting current; the increase of the exciting current leads to the magnetic saturation of the mutual inductor, thereby causing the error of the sampling current to be overlarge; meanwhile, the current transformer also has the defects of complex insulation structure, large volume, high cost and the like.

Disclosure of Invention

The invention aims to solve the problems and designs a method for measuring by adopting a PCB (printed circuit board) type current sensor for a single-phase intelligent electric energy meter.

The technical scheme of the invention is that a method for measuring by adopting a PCB type current sensor for a single-phase intelligent electric energy meter comprises the following steps:

step 1, fixedly mounting a PCB type current sensor on a zero line wiring terminal of a single-phase intelligent electric energy meter;

step 2, the power supply of the PCB type current sensor adopts a power supply sharing mode with the 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 level difference;

step 3, 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;

step 4, sending a voltage signal of the PCB type current sensor into a current sampling channel of a metering chip after passing through a resistance-capacitance anti-aliasing circuit, performing AD conversion, further calculating by the metering chip, and storing the voltage signal into a current register of the metering chip for calculating a subsequent current effective value and power;

step 5, the way of calculating the current effective value in step 4 is:

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 current register reading is calculated by the metering chip after AD conversion, and the 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_RMSObtaining the current value I of the current input;

step 6, when the sampling current of the electric energy meter is large, the temperature of an internal circuit of the current sensor is high, 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 large, and the correction mode 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).

Furthermore, when current flows through the electric energy meter, zero line current flows through the primary side of the current sensor, and due to the limitation of the current flowing area, the alternating current measuring range of the current sensor is 0-150A;

further, through the conversion of an internal circuit of the current sensor, the secondary side of the current sensor outputs a corresponding tiny voltage signal U; the signal sensitivity of the current sensor is 13.33mV/A, namely when 1A current flows through the sensor, the output voltage signal is 13.33 mV;

further, the PCB type current sensor is a SCT6101M module provided by the beijing smart core micro corporation.

Further, the primary side of 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 through screws.

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

Furthermore, 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, 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.

Advantageous effects

The method for measuring the single-phase intelligent electric energy meter by adopting the PCB type current sensor, which is manufactured by the technical scheme of the invention, has the following advantages:

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 reduces the cost;

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

Drawings

FIG. 1 is a schematic diagram of a method for measuring by using a PCB type current sensor for a single-phase intelligent electric energy meter according to the present invention;

fig. 2 is a diagram of an object of the PCB type current sensor of the present invention installed in an electric energy meter.

Detailed Description

The following detailed description of the present invention is provided with reference to the accompanying drawings, and as shown in fig. 1-2, the method for measuring by using a PCB type current sensor for a single-phase intelligent electric energy meter according to the present invention includes the following steps:

step 1, fixedly mounting a PCB type current sensor on a zero line wiring terminal of a single-phase intelligent electric energy meter;

step 2, the power supply of the PCB type current sensor adopts a power supply sharing mode with the 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;

step 3, 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;

step 4, sending a voltage signal of the PCB type current sensor into a current sampling channel of a metering chip after passing through a resistance-capacitance anti-aliasing circuit, performing AD conversion, further calculating by the metering chip, and storing the voltage signal into a current register of the metering chip for calculating a subsequent current effective value and power;

step 5, the way of calculating the current effective value in step 4 is:

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 current register reading is calculated by the metering chip after AD conversion, and the 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_RMSObtaining the current value I of the current input;

step 6, when the sampling current of the electric energy meter is large, the temperature of an internal circuit of the current sensor is high, 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 large, and the correction mode 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).

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 current sensor is an SCT6101M module provided by Beijing Intelligence core micro corporation, and one primary side of the 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 by using screws;

2. the power supply of the current sensor is direct current 5V, and a power supply mode shared by the current sensor and the metering chip is adopted, so that a power supply interface (red line in figure 1) and a ground line interface (black line in figure 1) 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. a differential voltage signal output end (a blue line in fig. 1) 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.

The technical solutions described above only represent the preferred technical solutions of the present invention, and some possible modifications to some parts of the technical solutions by those skilled in the art all represent the principles of the present invention, and fall within the protection scope of the present invention.