阅读说明：本技术 一种电能表电池欠压监测装置及其监测方法 (Device and method for monitoring undervoltage of battery of electric energy meter ) 是由 黄友朋 路韬 党三磊 赵闻 李倩 于 2020-07-07 设计创作，主要内容包括：本申请一种电能表电池欠压监测装置及其监测方法,包括供电电源、比较器、锁存器；所述供电电源分别与所述比较器和所述锁存器连接；所述比较器的第一输入端与电能表内部电池的电阻分压电路连接,输出端与所述锁存器的第一输入端连接；所述锁存器的输出端与电能表的MCU的信号输入端连接。相比较于现有技术,本申请利用锁存器对电池欠压信号进行持续锁存直至被检测到,可实现对电池欠压事件的准确监测,尤其是瞬时电压跌落的情形,可对电池欠压的瞬时信号进行及时捕获；本申请提供的监测装置结构简单,成本较低,可应用于现有的电能表内部电路,无需改变现有设计。(The application relates to an electric energy meter battery under-voltage monitoring device and a monitoring method thereof, which comprises a power supply, a comparator and a latch; the power supply is respectively connected with the comparator and the latch; the first input end of the comparator is connected with a resistance voltage division circuit of a battery in the electric energy meter, and the output end of the comparator is connected with the first input end of the latch; and the output end of the latch is connected with the signal input end of the MCU of the electric energy meter. Compared with the prior art, the method and the device have the advantages that the latch is used for continuously latching the battery under-voltage signal until the battery under-voltage signal is detected, so that the accurate monitoring of the battery under-voltage event can be realized, particularly the situation of instantaneous voltage drop, and the instantaneous signal of the battery under-voltage can be captured in time; the monitoring device provided by the application is simple in structure and low in cost, can be applied to an internal circuit of an existing electric energy meter, and does not need to change the existing design.)

1. The utility model provides an electric energy meter battery under-voltage monitoring devices which characterized in that includes:

a power supply, a comparator and a latch;

the power supply is respectively connected with the comparator and the latch, and the output voltage of the power supply is used as the power supply voltage of the comparator and the latch;

the first input end of the comparator is connected with a resistance voltage division circuit of a battery in the electric energy meter and used for sampling the voltage of the battery, and the output end of the comparator is connected with the first input end of the latch and used for sending an undervoltage signal to the latch;

the output end of the latch is connected with the signal input end of the MCU of the electric energy meter and used for sending the latched undervoltage signal to the MCU.

2. The undervoltage battery monitoring device of an electric energy meter according to claim 1, wherein said MCU further comprises a reset signal terminal connected to said second input terminal of said latch for sending a reset signal to said latch for clearing the state.

3. The undervoltage battery monitoring device according to claim 1, further comprising:

and the voltage reference unit is connected with the second input end of the comparator and used for providing a reference voltage.

4. The undervoltage battery monitoring device according to claim 1, wherein said latch is an RS flip-flop.

5. The undervoltage monitoring device for batteries of electric energy meters as claimed in claim 1, wherein the power supply is 2.5V power supply chip.

6. The undervoltage battery monitoring device according to claim 3, wherein the output voltage of said voltage reference unit is 1.25V.

7. A battery under-voltage monitoring method for realizing the battery under-voltage monitoring device of the electric energy meter according to any one of the claims 1 to 6, characterized by comprising the following steps:

the comparator samples the battery voltage, compares the battery voltage with a reference voltage, and outputs an undervoltage signal according to an undervoltage threshold value;

the latch acquires the undervoltage signal to latch and hold the undervoltage signal;

and the MCU monitors the undervoltage signal in the polling period.

8. The under-voltage battery monitoring method of claim 7, further comprising:

and the MCU outputs a reset signal to the latch to clear the latch state when detecting the undervoltage signal.

9. The method of claim 7, wherein the reference voltage is 1.25V.

Technical Field

The invention belongs to the field of electric energy meter detection, and particularly relates to an electric energy meter battery under-voltage monitoring device and a monitoring method thereof.

Background

Along with the construction and promotion of metering automation services in a power grid system, the intelligent electric energy meter has been popularized in a large range, and due to the fact that the total running amount of an external field put in the intelligent electric energy meter is large, battery under-voltage alarm of the electric energy meter often occurs, and one part of the battery under-voltage alarm belongs to false alarm, a monitoring device capable of accurately monitoring the battery under-voltage is needed. The existing battery under-voltage detection circuit is designed inside an electric energy meter, and the battery voltage is sampled, recorded and uploaded by a main control chip (MCU) in the operation process, however, the traditional battery voltage detection circuit has a simple structure, the MCU inspection working mode easily leaks and detects voltage drops occurring in the inspection interval period, and the voltage drops in the period easily cause abnormal actions of an MCU driver or other operations, so that the battery under-voltage event can not be truly reflected, and therefore, the device for accurately monitoring the real battery under-voltage event of the electric energy meter is necessary.

Disclosure of Invention

Based on this, the invention aims to provide an under-voltage monitoring device and a monitoring method for a battery of an electric energy meter, so as to overcome the defects of the prior art.

The invention relates to an electric energy meter battery under-voltage monitoring device, which comprises:

a power supply, a comparator and a latch;

the power supply is respectively connected with the comparator and the latch, and the output voltage of the power supply is used as the power supply voltage of the comparator and the latch;

the first input end of the comparator is connected with a resistance voltage division circuit of a battery in the electric energy meter and used for sampling the voltage of the battery, and the output end of the comparator is connected with the first input end of the latch and used for sending an undervoltage signal to the latch;

the output end of the latch is connected with the signal input end of the MCU of the electric energy meter and used for sending the latched undervoltage signal to the MCU.

Preferably, the MCU further comprises a reset signal terminal connected to the second input terminal of the latch for feeding back a reset signal to the latch.

Preferably, the battery under-voltage monitoring device of the electric energy meter further comprises:

and the voltage reference unit is connected with the second input end of the comparator and used for providing a reference voltage.

Preferably, the latch is an RS flip-flop.

Preferably, the power supply is a 2.5V power supply chip.

Preferably, the output voltage of the voltage reference unit is 1.25V.

On the other hand, the invention also provides an electric energy meter battery under-voltage monitoring method, which is realized by the monitoring device and comprises the following steps:

the comparator samples the battery voltage, compares the battery voltage with a reference voltage, and outputs an undervoltage signal according to an undervoltage threshold value;

the latch acquires the undervoltage signal to latch and hold the undervoltage signal;

the MCU monitors the undervoltage signal in the polling period.

Preferably, the method further comprises:

and when the MCU detects the undervoltage signal, the MCU outputs a reset signal to the latch to clear the latch state of the latch.

Preferably, the reference voltage is 1.25V.

According to the technical scheme, the invention has the following beneficial effects:

the invention relates to a device and a method for monitoring undervoltage of a battery of an electric energy meter.A latch is used for continuously latching an undervoltage signal of the battery until the undervoltage signal is detected, compared with the prior art that the voltage of the battery is directly sampled by an MCU (microprogrammed control unit), the device and the method can realize accurate monitoring of an undervoltage event of the battery, particularly can timely capture the undervoltage instantaneous signal of the battery under voltage; the monitoring device provided by the invention has the advantages of simple structure and lower cost, can be applied to the internal circuit of the existing electric energy meter, and does not need to change the existing design.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

FIG. 1 is a block diagram of an embodiment of an under-voltage monitoring device for a battery of an electric energy meter

FIG. 2 is a schematic diagram of a battery under-voltage monitoring circuit of an electric energy meter according to another embodiment of the present invention

FIG. 3 is a flow chart of an implementation of a method for monitoring under-voltage of a battery of an electric energy meter according to another embodiment of the invention

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1, the present embodiment provides an under-voltage monitoring device for a battery of an electric energy meter, including a power supply, a voltage reference unit, a comparator, and a latch;

the power supply is powered by a main power VCC and a battery at the same time, a power conversion chip with a wide input voltage range is used and is respectively connected with the comparator and the latch, and the output voltage of the power supply provides power supply voltage for the comparator and the latch;

the first input end of the comparator is connected with a resistance voltage division circuit of a battery in the electric energy meter, and the output end of the comparator is connected with one end of the latch; the other end of the latch is connected with the signal input end of the electric energy meter MCU.

The MCU also comprises a reset signal end which is used for outputting a reset signal to the latch, clearing the state of the latch after the battery under-voltage signal is inspected and waiting for the next under-voltage signal latch.

In a further embodiment, the power conversion chip of the power supply can select a power chip of 3.3V, 2.8V, or 2.5V according to actual requirements, and the power chip of 2.5V is selected in this embodiment.

The voltage reference unit in this embodiment uses a voltage reference chip with low power consumption and a wide input voltage range, and the output voltage may be selected to be 1.2V or 1.25V or 2.048V, which is lower than the under-voltage threshold of the battery by 3.3V, and is used as the voltage reference of the comparator. It should be understood that the voltage reference unit is not necessary when the comparator has its own reference voltage, and those skilled in the art can select the voltage reference unit according to the actual comparator, and the embodiment is only illustrated in fig. 1, and will not be listed and described further herein.

The comparator in the embodiment adopts an operational amplifier with low power consumption and wide input voltage range, the battery voltage is sampled through a resistance voltage division circuit, the comparator is compared with a voltage reference, and when the battery voltage is monitored to be lower than an undervoltage threshold value, the comparator outputs an undervoltage signal (high or low level); the judgment voltage threshold value of the undervoltage signal output by the comparator is consistent with the specified battery undervoltage threshold value by selecting a proper voltage reference or adjusting the resistance voltage dividing circuit.

It should be understood that the level signal output by the comparator may not be limited to indicate the battery under-voltage, and the level signal output by the comparator when the battery voltage is in a normal state can be latched by the latch, so that the latch state output by the latch in the present invention is not limited to the battery under-voltage.

Referring to fig. 2 and fig. 3, the present embodiment provides a battery under-voltage monitoring circuit for an electric energy meter, which is designed inside the electric energy meter and is used for monitoring battery under-voltage of the electric energy meter in real time.

As shown in fig. 2, the monitoring circuit of the present embodiment mainly includes four units, i.e., a power supply (D1, C1, U1, and C2), a voltage reference unit (U2), a comparator circuit (R1, R2, and U3A), and a latch circuit (U4, R3, and D2).

The power supply is powered by a main power supply Vmains power supply and a Battery through an input end Vin simultaneously, the main power supply Vmains power supply is selected as a main working circuit through a diode D1, the power supply adopts a power supply conversion chip U1 with a wide input voltage range, and the output voltage Vout of the power supply is the power supply voltage of a comparator U3A and a voltage reference unit U2; specifically, the power supply of this embodiment selects a 2.5V power chip as the power conversion chip.

The voltage reference unit U2 of this embodiment uses a voltage reference chip with low power consumption and a wide input voltage range, the output voltage of 1.25V is used as the voltage reference of the comparator circuit and is far lower than the under-voltage threshold of the battery by 3.3V, and the output end of the voltage reference unit U2 is connected with the non-inverting input end of the comparator U3A to provide the comparison reference voltage.

The comparator circuit uses an operational amplifier U3A with low power consumption and wide input voltage range, samples the battery voltage VBat through resistance voltage division R1 and R2 to obtain a sampling voltage value VBatSamp, compares the sampling voltage value VBatSamp with a voltage reference Vref through a comparator U3A, and outputs an undervoltage signal high level when the battery voltage is monitored to be lower than an undervoltage threshold value; the judgment voltage threshold of the undervoltage signal output by the comparator circuit is consistent with the specified battery undervoltage threshold by selecting proper R1 and R2 resistance voltage division.

The latch U4 of the embodiment is an asynchronous RS trigger, and captures the high level of the undervoltage signal through the SN end to latch and maintain the undervoltage signal, so that the MCU can detect the undervoltage signal through a DetectSignal pin in the polling period, and the latch can latch and maintain the undervoltage signal to provide enough maintaining time for the next polling of the MCU, thereby avoiding missing detection of the instantaneous voltage drop occurring in the polling interval; and after the MCU patrols and obtains the undervoltage signal, outputting a Reset signal to the RN end of the latch U4 through a Reset pin Reset to clear the state of the trigger and wait for the next acquisition of the undervoltage signal.

As shown in fig. 3, the operation of the under-voltage battery monitoring circuit of the present embodiment is described as follows:

the comparator U3A samples the battery voltage and compares the battery voltage with a reference voltage Vref, and outputs an undervoltage signal according to an undervoltage threshold;

the latch U4 acquires the undervoltage signal through the SN end to latch and hold the undervoltage signal;

the MCU monitors the undervoltage signal through a DetectSignal pin in the polling period;

when the MCU detects the undervoltage signal, the MCU outputs a Reset signal to the RN end of the latch U4 through a Reset pin to clear the latch state of the RN end.

The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.