CN112213555A

CN112213555A - Electric energy meter solution method based on high-speed magnetic isolation communication

Info

Publication number: CN112213555A
Application number: CN201911326909.5A
Authority: CN
Inventors: 刁瑞朋; 闫乐乐; 解文豪
Original assignee: Qingdao Topscomm Communication Co Ltd
Current assignee: Qingdao Topscomm Communication Co Ltd
Priority date: 2019-12-20
Filing date: 2019-12-20
Publication date: 2021-01-12

Abstract

The invention discloses a method for solving an electric energy meter for high-speed magnetic isolation communication, which comprises the following steps: the device comprises a central processing unit, a data acquisition module, a communication module, an electric energy metering module, a storage module, a display module, a safe transmission module and a power supply module. The data acquisition module, the electric energy metering module, the storage module, the display module, the safety transmission module and the power supply module are respectively connected with the central processing unit, and the communication module is mutually connected with the safety transmission module. Compared with the prior art, the invention adopts a more stable and multifunctional high-speed magnetic isolation communication connection mode in the connection mode of the electric energy metering module and the central processing unit.

Description

Electric energy meter solution method based on high-speed magnetic isolation communication

Technical Field

The invention belongs to the field of intelligent electric energy meters, and particularly relates to an electric energy meter solution method based on high-speed magnetic isolation communication.

Background

In an electric meter, the interface parts of an RS485 communication module and a metering module often have impact such as misoperation, static electricity or lightning surge, high voltage can be generated at the interface end, if safe isolation is not available among the modules, overvoltage can be transmitted in equipment through a power supply and a ground wire, an interface chip can be damaged, and a core chip MCU can be involved. Therefore, the industry generally supplies power to each module independently, and the front stage and the rear stage are isolated in various ways to ensure the safety of equipment and operators.

At present, electric energy meters basically adopt optical couplers for isolation, and the basic implementation structure is shown in figure 1. In the isolation scheme based on the optocoupler, a power supply needs to provide three paths of isolation power supplies to respectively supply power to the main MCU control circuit, the RS485 communication circuit and the metering circuit; the power supply design needs to add transformer windings for isolation to supply power to each isolation module, and each winding needs to provide an independent rectification voltage stabilizing circuit. This results in complex power supply structure, large size, complex peripheral circuitry, difficult PCB layout, and high cost. As in the isolation scheme of fig. 1, at least 3 isolated power supplies are required, which is a high requirement for power supply design. The optical coupling isolation scheme also has the defect of low effective transmission rate.

Disclosure of Invention

The invention aims to provide a method for solving a high-speed magnetic isolation communication electric energy meter.

The technical scheme of the invention is that on the basis of fully considering the application requirements of the electric energy meter, a brand-new magnetic coupling transmission technology is used, isolation power supply and isolation communication are both considered, and the power supply and communication of a master MCU control circuit, a slave RS485 circuit and a metering circuit are realized by utilizing a magnetic coupling isolation chip and a magnetic coupling transformer; a new generation of electric energy meter solution is formed by adopting a single-path power supply scheme of transformer single-path tap output. The defects of an optical coupler and the defects of complex process and poor application stability of a multi-output transformer are overcome.

The method is characterized in that: a. the electric energy meter main MCU is connected with the slave end through the magnetic coupling isolation chip and the magnetic coupling transformer, and the electric isolation between the main MCU and the slave end is realized by utilizing the electric isolation performance of the magnetic coupling transformer. b. The power supply of the whole electric energy meter is provided for the main MCU by the single-path power supply output of the power circuit; and the power supply of the slave end circuit is realized by the main MCU end through a magnetic coupling isolation chip and a magnetic coupling transformer by adopting modulation-demodulation and rectification filtering technologies.

The electric energy meter main MCU is provided with a UART interface, and a magnetic coupling isolation main chip is integrated in the electric energy meter main MCU and used for completing communication and power supply with a slave end.

The slave end refers to an RS485 circuit and a metering circuit of the ammeter, wherein a magnetic coupling isolation slave chip is integrated inside the RS485 chip, and a magnetic coupling isolation slave chip is also integrated inside the metering chip.

The magnetic coupling isolation chip is divided into a magnetic coupling isolation main chip and a magnetic coupling isolation slave chip. The main chip adopts a frequency modulation technology to realize digital signal transmission, and adopts an amplitude demodulation technology to realize digital signal reception; the slave chip adopts a frequency demodulation technology to realize digital signal receiving, and adopts an amplitude modulation technology to realize digital signal sending.

The magnetic coupling transformer completes energy conversion and signal transmission of the primary coil and the secondary coil through magnetic circuit coupling.

The electrical isolation comprises communication isolation and power supply isolation. The communication isolation means transmits digital signals through a magnetic coupling transformer to realize bidirectional half-duplex asynchronous serial communication at a master end and a slave end; the power supply isolation means that the slave end power supply is provided by the master end MCU through a magnetic coupling transformer.

The single-path power output means that the power module only provides one path of power for the main MCU module, the RS485 module and the metering circuit module are not independently powered by the power transformer, the secondary voltage output of the power module transformer is simplified from the previous three paths to only one path, only one group of secondary coils of the power module transformer is provided, and only one path of secondary rectifying and filtering circuit of the power module transformer is provided.

Drawings

FIG. 1: and (4) an optical coupling isolation communication scheme system block diagram.

FIG. 2: magnetic coupling isolation communication scheme system block diagram.

FIG. 3: a new generation electric energy meter block diagram based on magnetic coupling communication and single-path power supply output technology.

Detailed Description

A power module of the electric energy meter completes the conversion from alternating current to direct current power supply through the access of 220V alternating current, the conversion of an AC-DC power module and a primary secondary winding of a transformer, the secondary output of the power module is only one path, the secondary output winding of the transformer is only one group, and then a rectifying circuit of the secondary output of the transformer provides stable power for a main MCU control module.

Compared with the existing three-way output transformer, the single-way secondary winding output transformer has the advantages of simpler structure, more optimized manufacturing process, greatly improved performance reliability, and more advantageous production efficiency and cost. Only one path of power supply output is needed, only one path of rectifying and filtering circuit is needed, other two paths of rectifying and filtering circuits are saved, the number of power supply circuit devices is less, the layout and wiring are more convenient, the area of a board can be effectively reduced, and the cost is saved; in addition, the circuit is simple, and the reliability is higher, and radiation and conducted interference that power supply circuit produced reduce by a wide margin, and ammeter EMC performance is better.

The master MCU control module modulates digital signals with different frequencies through a master chip of magnetic coupling communication integrated in the MCU, finishes signal transmission and energy transmission from the master MCU control module to a slave module (such as an RS485 communication module and a metering communication module) through a primary coil, a secondary coil and a magnetic coupling of a magnetic coupling transformer and a passage, finishes demodulation and reception of signals through a demodulation module of a slave chip of the magnetic coupling communication integrated in the chip respectively by an RS485 chip and a metering chip of a slave module chip of the magnetic coupling communication integrated in the chip, finishes power supply energy conversion from the master MCU module to the slave module through a rectification filter circuit in the slave chip of the magnetic coupling communication, and provides stable power supply for the RS485 communication module and the metering communication module. In the whole process, the magnetic coupling transformer undertakes signal transmission and energy transmission, and ensures the electrical and physical isolation among different circuit modules. The number of devices is reduced by an isolated power supply mode, and the reliability of the whole meter is effectively improved.

The power supply is isolated through the magnetic coupling transformer, and a traditional power frequency/switch power supply transformer independent auxiliary winding isolation power supply circuit is omitted. The bidirectional half-duplex asynchronous serial communication is realized through the magnetic coupling isolation transformer, and a traditional optical coupling isolation circuit is omitted.

The magnetic coupling power supply/communication system is composed of a host machine and a slave machine. The master refers to an MCU module, and the slave refers to a module which needs to be electrically isolated from the periphery of the MCU, such as a metering chip or a 485 communication module. There may be more than one slave derived.

The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes performed by the present specification and drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.

Claims

1. A method for solving an electric energy meter based on high-speed magnetic isolation communication is disclosed. The method is characterized in that: a. the electric energy meter main MCU is connected with the slave end through the magnetic isolation chip and the magnetic coupling transformer, and the electric isolation between the main MCU and the slave end is realized by utilizing the electric appliance isolation performance of the magnetic coupling transformer. b. The whole electric energy meter is powered, and a power circuit outputs a single power supply to a main MCU; and the power supply of the slave end circuit is realized by the main MCU end through a magnetic coupling transformer by adopting modulation regulation and rectification filtering technologies.

2. The electric energy meter main MCU of claim 1, having UART interface, internally integrating magnetic coupling isolation main chip for communication and power supply with slave end.

3. The slave end according to claim 1 is a metering circuit of an electricity meter, wherein the metering chip is internally integrated with a magnetic coupling isolation slave chip.

4. The magnetically coupled isolated chip of claim 1, being divided into a magnetically coupled isolated master chip and a magnetically coupled isolated slave chip. The main chip adopts a frequency modulation technology to realize digital signal transmission, and adopts an amplitude demodulation technology to realize digital signal reception; the slave chip adopts a frequency demodulation technology to realize digital signal receiving, and adopts an amplitude modulation technology to realize digital signal sending.

5. The magnetically-coupled transformer of claim 1, wherein the primary coil and the secondary coil are coupled by a magnetic circuit to perform energy conversion and signal transmission.

6. The electrical isolation of claim 1, comprising communication isolation and power supply isolation. The communication isolation means transmits digital signals through a magnetic coupling transformer to realize bidirectional half-duplex asynchronous serial communication at a master end and a slave end; the power supply isolation means that the slave end power supply is provided by the master end MCU through a magnetic coupling transformer.

7. The single-path power output as claimed in claim 1, means that the power module only provides one path of power to the main MCU module and the metering circuit module is no longer powered by the power transformer alone, the secondary voltage output of the power module transformer is reduced from the previous three paths to only one path, there is only one set of secondary windings of the power module transformer, and there is only one path of secondary rectifying and filtering circuit of the power module transformer.