CN217212904U

CN217212904U - Distribution network automation terminal battery voltage and current acquisition circuit

Info

Publication number: CN217212904U
Application number: CN202220446260.1U
Authority: CN
Inventors: 黄亮; 周学成; 刘世验; 艾少鹏
Original assignee: Wasion Electric Co Ltd
Current assignee: Weisheng Energy Technology Co ltd
Priority date: 2021-12-29
Filing date: 2022-03-02
Publication date: 2022-08-16
Anticipated expiration: 2032-03-02

Abstract

The utility model discloses a distribution network automation terminal battery voltage and current acquisition circuit, which comprises a current acquisition circuit and a voltage acquisition circuit, wherein the current acquisition circuit comprises an acquisition interface, and the acquisition interface is respectively and electrically connected with a second resistor, two ends of a storage battery and a current acquisition circuit; the current acquisition circuit comprises a current detector which is connected with the second resistor in parallel; the current detector is electrically connected with the voltage acquisition circuit, the voltage acquisition circuit comprises a third resistor, and one end of the third resistor is electrically connected with one end of a fourth resistor and the conversion chip; the other end of the third resistor is electrically connected with one pole of the storage battery, and the other end of the fourth resistor is electrically connected with the other pole of the storage battery to form a loop. The utility model discloses have high gain input scope, sampling high accuracy, the collection of distribution network automation terminal battery voltage electric current is satisfied in the design of binary channels, improves the duration at distribution network automation terminal.

Description

Distribution network automation terminal battery voltage and current acquisition circuit

Technical Field

The utility model belongs to the technical field of the electron, especially, relate to a distribution network automation terminal battery voltage and current acquisition circuit.

Background

With the increasing demand of the distribution network automation terminal part on intelligent battery management and functions, the demand on high-precision and low-power-consumption battery voltage and current monitoring becomes stronger and stronger. Conventionally, configured as a differential amplifier, a plurality of voltage and current monitoring amplifiers built in the system perform such voltage and current monitoring. The delay between voltage and current measurement is large, a gain amplifier needs to be built by an external operational amplifier, and the traditional 12-bit ADC cannot meet the increase of the requirements on intelligent management and functions of a battery.

Traditional mode, current acquisition often needs to do gain amplification to current signal and handles, traditional gain amplifier need lean on external operational amplifier to build the common mode, the input range is low, and the inside 12 bit ADC of singlechip gathers the increase that the data precision can not satisfy the demand to battery intelligent management and function, do not possess transient state protection simultaneously, receive electric wire netting voltage fluctuation and damage easily, in order to improve the common mode input range of voltage current sampling, improve sampling precision and anti-interference protection ability, consequently, a distribution automation terminal battery voltage and current acquisition circuit has been proposed.

SUMMERY OF THE UTILITY MODEL

The problems of overcharge, overdischarge, overcurrent damage of current and the like of the battery caused by incapability of accurately monitoring the voltage and the current of the battery in the actual use process of the distribution network automation terminal device are solved.

In order to achieve the above purpose, the technical scheme of the utility model is that:

a distribution network automation terminal battery voltage and current acquisition circuit comprises a current acquisition circuit and a voltage acquisition circuit, wherein the current acquisition circuit comprises an acquisition interface, and the acquisition interface is respectively and electrically connected with a second resistor, two ends of a storage battery and the current acquisition circuit; the current acquisition circuit comprises an INA282 current detector, wherein the INA282 current detector is connected with a second resistor in parallel; the INA282 current detector is electrically connected with a voltage acquisition circuit, the voltage acquisition circuit comprises a third resistor, and one end of the third resistor is electrically connected with one end of a fourth resistor and the MCP3422AD conversion chip; the other end of the third resistor is electrically connected with one pole of the storage battery, and the other end of the fourth resistor is electrically connected with the other pole of the storage battery to form a loop.

In a further improvement, the current acquisition circuit comprises an acquisition interface, the acquisition interface is provided with a ninth pin and a tenth pin, the ninth pin is electrically connected with a second resistor and a fifth resistor, and the tenth pin is electrically connected with a battery BAT-pole; the second resistor is electrically connected with a battery BAT + pole and the first resistor; the first resistor is electrically connected with an eighth pin of the current detector; the fifth resistor is electrically connected with a first pin of the current detector; the eighth pin is electrically connected with a first protection diode and a second capacitor, and the first pin is electrically connected with a second protection diode and a fifth capacitor; the first protection diode, the second capacitor and the fifth capacitor are all grounded; a third capacitor is electrically connected between the eighth pin and the first pin; the second pin, the third pin and the seventh pin of the current detector are all grounded; a sixth pin of the current detector is electrically connected with a power supply and a first capacitor, and the first capacitor is grounded; the fifth pin of the current detector is electrically connected with the eleventh pin of the MCP3422AD conversion chip.

In a further improvement, one end of the third resistor is electrically connected with a storage battery BAT +, the other end of the third resistor is electrically connected with a fourteenth pin of the MCP3422AD conversion chip, and the other end of the fourth resistor is electrically connected with the storage battery BAT-; a sixteenth pin of the MCP3422AD conversion chip is electrically connected with a power supply and a fourth capacitor, and the fourth capacitor is grounded; and the twelfth pin, the thirteenth pin and the fifteenth pin of the AD conversion chip are all grounded.

In a further improvement, the first resistor and the fifth resistor are both current-limiting resistors with a resistance value of 10 Ω.

In a further improvement, the first capacitor, the second capacitor, the third capacitor, the fourth capacitor and the fifth capacitor are all filter capacitors of 0.1 uF.

In a further improvement, the second resistor is a current sampling resistor of 0.1 Ω.

In a further improvement, the third resistor and the fourth resistor are both voltage sampling resistors, the resistance of the third resistor is 30K Ω, and the resistance of the fourth resistor is 1.2K Ω.

The utility model has the advantages that:

1. the circuit of the utility model has high gain input range and instantaneous protection range, and high sampling precision;

2. the dual-channel design is adopted to meet the requirement of collecting the voltage and the current of the storage battery of the distribution network automation terminal, and the cruising ability of the distribution network automation terminal is improved.

Drawings

Fig. 1 is a schematic diagram of the circuit structure of the present invention.

Detailed Description

The present invention will be further explained with reference to the drawings and the embodiments.

Example 1

A distribution automation terminal battery voltage and current acquisition circuit as shown in fig. 1, comprising a current acquisition circuit: after J1 and R2 are connected in series, R2 is connected to a BAT + pole of the storage battery power supply, a tenth pin of J1 is connected to a BAT-pole of the storage battery power supply, one end of R1 and the BAT + are connected, the other end of the R1 and the BAT + are connected to be connected to an eighth pin of U2, one end of R5 is connected to be connected with a ninth pin of J1, and the other end of the R5 is connected to be the first pin of U2. The cathode of the D1 is connected with the eighth pin of the U2, the anode is grounded, the cathode of the D2 is connected with the first pin of the U2, the anode is grounded, the C3 is connected between the first pin and the eighth pin of the U2 in parallel, one end of the C1 is connected with the eighth pin of the U2, the other end of the C1 is grounded, one end of the C5 is connected with the first pin of the U2, the other end of the C5 is grounded, the second, third and seventh pins of the U2 are grounded, the fourth pin is empty, the fifth pin is connected with the first pin of the U3, the sixth pin of the U2 is connected with the power supply VDD and one end of the capacitor C1, and the other end of the capacitor C1 is grounded.

The voltage acquisition circuit: the resistors R3 and R4 are connected in series and then connected between the BAT + pole and the BAT-negative pole of the storage battery power supply in parallel, and one end of R3 is connected with BAT +; the other end of the R4 is connected with a fourteenth pin of the U3, and one end of the R4 is connected with BAT-; the other end of the U-shaped resistor is connected to a fourteenth pin of the U3, the twelfth, thirteenth and fifteenth pins of the U3 are grounded, the sixteenth pin is connected with VDD and is also connected with a capacitor C4 in parallel, the other end of the C4 is grounded, the seventeenth pin of the U3 is connected with the MCU _ SDA, the eighteenth pin of the U3 is connected with the MCU _ SCL, and the nineteen pin of the U3 is connected with the ADDR 0; the twentieth pin of U3 is connected to ADDR 1.

The working principle is as follows:

in the figure, J1 is an acquisition interface of a distribution network automation terminal LOAD, and R2 is a current sampling resistor of 0.1 Ω; r1 and R5 are 10 omega current limiting resistors, D1 and D2 are TVS protection diodes, U2 is INA282 is a current detector, and R3 and R4 are voltage sampling resistors which are respectively 30K omega and 1.2K omega; the MCP3422 is an AD conversion chip. C1, C2, C3, C4 and C5 are 0.1uF filter capacitors.

Current collection procedure

The INA282 is a high-precision wide common-mode input range bidirectional current detector, the chip can accurately measure the voltage drop in the voltage range of-14V to +80V, has a wide common-mode input range, can work in the power supply working range of +2.7V to +18V, can work at the temperature of-40 ℃ to +125 ℃, has a small volume, and is packaged as SOIC-8. The transient protection internal gain can reach 50V/V. Transient protection range from 12V battery reverse to up to +80V transient; no additional protection components are required to achieve these levels.

After the distribution network automation terminal is powered on, the device is powered by the electric quantity stored in the storage battery and flows through R2 and a sampling resistor of 0.1 omega; r1 and R5 are 10 omega current limiting resistors and limit the input current of INA282, D1 and D2 are TVS protection diodes and can protect a circuit from damaging a current detector due to grid voltage fluctuation and excessive instantaneous voltage, the current detection current U2 amplifies the voltage of the R2 sampling resistor by 50 times and outputs the amplified voltage, and according to a calculation formula, the U2 current detection voltage VOUT (load) is equal to I (load) R2, and I (load) is equal to the load current flowing through two ends of R2 when a storage battery is powered.

(2) Voltage acquisition process

The detection of voltage signal quantity acquired by the storage battery adopts a double-resistor voltage division mode, two resistors with proper resistance values are connected in series for voltage division, voltage signals after voltage division are sent, and R3 and R4 are voltage sampling resistors and are respectively 30K omega and 1.2K omega; according to the calculation formula, Vch2 is Vbat R4/(R3+ R4), Vch2 is the input voltage of channel 2 of the U3 analog-to-digital conversion chip, Vbat is the storage battery voltage, namely Vch2 is Vbat 1.2/(30+1.2)

MCP3422 is AD conversion chip, and the 18 bit ADC that provide differential input has the characteristics of high resolution, low-power consumption, and the design of fourteenth pin just satisfies the collection of distribution network automation terminal battery voltage electric current, and internally integrated programmable gain amplifier, voltage reference and oscillator, novel ADC significantly reduced required external component quantity, dwindle PCB board design volume, carry out 3V continuous conversion and only consume 135mA electric current, improve the duration at distribution network automation terminal. Direct IIC interface MCU _ SDA and MCU _ SCL output, provide to singlechip processing, can change independently each other. The delay between the voltage and current measurements is minimized.

C1, C2, C3, C4 and C5 are 0.1uF filter capacitors. Voltage and current acquisition requires a power supply bypass capacitor to realize stability. Power supply noise is suppressed. The bypass capacitor is connected to a location proximate to the device pin.

Improve the sampling precision and stability of the system

While the embodiments of the invention have been disclosed above, it is not limited to the applications listed in the description and embodiments, but is capable of being applied in all kinds of fields where the invention is suitable, and further modifications may readily be made by those skilled in the art, and the invention is therefore not limited to the details shown and described herein, without departing from the general concept defined by the appended claims and their equivalents.

Claims

1. The distribution network automation terminal battery voltage and current acquisition circuit comprises a current acquisition circuit and a voltage acquisition circuit, and is characterized in that the current acquisition circuit comprises an acquisition interface (J1), and the acquisition interface (J1) is respectively and electrically connected with a second resistor (R2), two ends of a storage battery and the current acquisition circuit; the current acquisition circuit comprises an INA282 current detector (U2), the INA282 current detector (U2) being connected in parallel with a second resistor (R2); the INA282 current detector (U2) is electrically connected with a voltage acquisition circuit, the voltage acquisition circuit comprises a third resistor (R3), one end of the third resistor (R3) is electrically connected with one end of a fourth resistor (R4) and an MCP34 3422AD conversion chip (U3); the other end of the third resistor (R3) is electrically connected with one pole of the storage battery, and the other end of the fourth resistor (R4) is electrically connected with the other pole of the storage battery to form a loop.

2. The distribution network automation terminal battery voltage and current collection circuit according to claim 1, characterized in that the collection interface (J1) is provided with a ninth pin (9) and a tenth pin (10), the ninth pin (9) is electrically connected with a second resistor (R2) and a fifth resistor (R5), the tenth pin (10) is electrically connected with a battery BAT-pole; the second resistor (R2) is electrically connected with a battery BAT + pole and a first resistor (R1); the first resistor (R1) is electrically connected with an eighth pin (8) of a current detector (U2); the fifth resistor (R5) is electrically connected with a first pin (1) of a current detector (U2); the eighth pin (8) is electrically connected with a first protection diode (D1) and a second capacitor (C2), and the first pin (1) is electrically connected with a second protection diode (D2) and a fifth capacitor (C5); the first protection diode (D1), the second protection diode (D2), the second capacitor (C2) and the fifth capacitor (C5) are all grounded; a third capacitor (C3) is electrically connected between the eighth pin (8) and the first pin (1); the second pin (2), the third pin (3) and the seventh pin (7) of the current detector (U2) are all grounded; the sixth pin (6) of the current detector (U2) is electrically connected with a power supply and a first capacitor (C1), and the first capacitor (C1) is grounded; the fifth pin (5) of the current detector (U2) is electrically connected with the eleventh pin (11) of the MCP3422AD conversion chip (U3).

3. The distribution network automation terminal battery voltage and current collection circuit according to claim 2, characterized in that one end of the third resistor (R3) is electrically connected with a battery BAT +, the other end of the third resistor (R3) is electrically connected with a fourteenth pin (14) of a MCP3422AD conversion chip (U3), and the other end of the fourth resistor (R4) is electrically connected with a battery BAT-; a sixteenth pin (16) of the MCP3422AD conversion chip (U3) is electrically connected with a power supply and a fourth capacitor (C4), and the fourth capacitor (C4) is grounded; the twelfth pin (12), the thirteenth pin (13) and the fifteenth pin (15) of the AD conversion chip (U3) are all grounded.

4. The distribution network automation terminal battery voltage and current collection circuit of claim 2, wherein the first resistor (R1) and the fifth resistor (R5) are both current limiting resistors with a resistance of 10 Ω.

5. A distribution network automation terminal battery voltage and current harvesting circuit according to claim 3, characterized in that the first (C1), second (C2), third (C3), fourth (C4) and fifth (C5) capacitors are all 0.1uF filter capacitors.

6. A distribution automation terminal battery voltage and current collection circuit as claimed in claim 1 characterised in that the second resistor (R2) is a 0.1 Ω current sampling resistor.

7. The distribution network automation terminal battery voltage and current collection circuit of claim 1, wherein the third resistor (R3) and the fourth resistor (R4) are voltage sampling resistors, the third resistor (R3) has a resistance of 30K Ω and the fourth resistor (R4) has a resistance of 1.2K Ω.