CN209542680U - A kind of electric instrument - Google Patents

Abstract

The utility model discloses an electric meter. The electric power meter of the utility model includes a housing; a parameter measuring terminal arranged on the side of the housing and a control main board arranged inside the housing, the parameter measuring terminal is connected with the control main board, and the control main board is used for measuring electric parameters. The power meter of the utility model can measure a variety of electrical parameters, has high measurement accuracy and reasonable structural design, can automate the measurement process and data analysis and processing, reduce human errors, and can effectively improve the integration and stability of power supply system parameter monitoring. reliability.

Description

a power meter

technical field

The utility model relates to an electric meter.

Background technique

With the continuous improvement of the degree of industrialization, the power consumption of enterprises has increased sharply, and the normal operation of the power supply system of enterprises has become particularly important. The multifunctional power monitoring instrument has been widely used in the monitoring field of power supply system. It has fundamentally changed the monitoring method of the traditional power supply system and greatly improved the operating efficiency of the power supply system.

At present, different types of control systems appear in various fields of industry. It is necessary to ensure the normal operation of the control system during the power supply process. It is necessary to use a variety of power meters to measure various parameters in the operation of the control system, such as the measurement of current and voltage. , the statistics of electric energy, the monitoring of the electric energy load of the electronic instrument and the alarm of the electric measurement quantity exceeding the limit, etc., because the function of the traditional electric meter is relatively single, which requires a variety of electric meters to monitor the control system at the same time , It also makes the system wiring configuration too complicated, the operation automation degree is low, the fault finding and maintenance are more difficult, and the loss of the system is also greatly increased.

Utility model content

The utility model provides an electric power meter to solve the problem that the single function of the existing electric power meter requires complex wiring for the monitoring and control system, which results in a low degree of automatic operation of the system, difficulties in failure and maintenance, and increased damage to the system.

In order to achieve the above object, the technical solution of the utility model is achieved in that:

The utility model provides an electric power meter, which comprises a shell; a parameter measuring terminal arranged on the side of the shell and a control main board arranged inside the shell, the parameter measuring terminal is connected with the control main board, and the control main board is used for measuring electric parameters.

Optionally, the parameter measurement terminals include: three-phase current input terminals, three-phase voltage input terminals, temperature input terminals, and leakage current input terminals.

Optionally, the control board is provided with a microcontroller, a current sampling circuit, a voltage sampling circuit, and an electric energy metering circuit; the three-phase current input terminal is connected to the current sampling circuit, the three-phase voltage input terminal is connected to the voltage sampling circuit, and the current sampling circuit Both the voltage sampling circuit and the electric energy metering circuit are connected with the electric energy metering circuit, and the electric energy metering circuit is connected with the microcontroller through the SPI data bus.

Optionally, the microcontroller is also connected to a non-volatile memory.

Optionally, the current sampling circuit includes a-phase current sampling branch, b-phase current sampling branch and c-phase current sampling branch with the same circuit structure, and each phase current sampling branch includes a current transformer; the voltage sampling circuit includes a circuit The a-phase voltage sampling branch, the b-phase voltage sampling branch and the c-phase voltage sampling branch have the same structure, and each phase voltage sampling branch includes a voltage transformer; the electric energy metering circuit adopts the RN7302 chip as the three-phase electric energy metering chip.

Optionally, the power meter further includes: a communication interface arranged on the side of the casing and a remote communication circuit arranged on the control board, the communication interface is connected to the remote communication circuit, and the remote communication circuit is connected to the microcontroller.

Optionally, the remote communication circuit adopts MODBUS communication transmission protocol.

Optionally, a switching value input circuit and a switching value output circuit respectively connected to the microcontroller are also arranged on the control main board.

Optionally, the power meter further includes: a display screen and operation buttons arranged on the surface of the casing, the display screen is connected to the microcontroller, and the operation buttons are connected to the I/O port of the microcontroller.

Optionally, the power meter further includes: a power supply connection terminal arranged on the side of the casing and a switching power supply arranged inside the casing; the power supply connection terminal is connected to the switching power supply, and the switching power supply is connected to the control board to supply power to the power meter.

The power meter of the utility model can measure various electrical parameters, has high measurement accuracy and reasonable structural design, can automate the measurement process and data analysis and processing, reduce human errors, and can effectively improve the integration and stability of power supply system parameter monitoring. reliability.

Description of drawings

Fig. 1 is the electric meter schematic diagram that the utility model embodiment shows;

Fig. 2 is the schematic circuit diagram of the microcontroller shown in the utility model embodiment;

3-5 are circuit diagrams of the a-phase current sampling branch, the b-phase current sampling branch and the c-phase current sampling branch shown in the embodiment of the utility model in turn;

Figures 6-8 are schematic circuit diagrams of the a-phase voltage sampling branch, the b-phase voltage sampling branch and the c-phase voltage sampling branch shown in the embodiment of the utility model in turn;

Fig. 9 is a schematic circuit diagram of an electric energy metering circuit shown in an embodiment of the present invention;

Fig. 10 is a schematic circuit diagram of a switching value input circuit shown in an embodiment of the present invention;

Fig. 11 is a schematic circuit diagram of a switch output circuit shown in an embodiment of the present invention;

FIG. 12 is a schematic circuit diagram of a remote communication circuit shown in an embodiment of the present invention.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present utility model clearer, the implementation of the present utility model will be further described in detail below in conjunction with the accompanying drawings.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be understood, however, that these descriptions are exemplary only and are not intended to limit the scope of the present invention. Also, in the following description, descriptions of well-known structures and techniques are omitted to avoid unnecessarily obscuring the concept of the present invention.

The terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting of the invention. The words "a", "an" and "the" used herein shall also include the meanings of "plurality" and "multiple", unless the context clearly indicates otherwise. In addition, the terms "comprising", "comprising", etc. used herein indicate the existence of stated features, steps, operations and/or components, but do not exclude the existence or addition of one or more other features, steps, operations or components .

All terms (including technical and scientific terms) used herein have the meaning commonly understood by one of ordinary skill in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted to have a meaning consistent with the context of this specification, and not be interpreted in an idealized or overly rigid manner.

The power meter of this embodiment includes: a housing, a parameter measurement terminal arranged on the side of the housing and a control board arranged inside the housing, the parameter measurement terminal is connected to the control board, and the control board is used to measure electrical parameters, including the As well as the active power, reactive power, apparent power, active energy and reactive energy of the combined phase, it can also measure the current, voltage effective value, power factor, phase angle, frequency and other parameters of each phase.

Fig. 1 is a schematic diagram of a power meter shown in an embodiment of the present invention. As shown in Fig. 1 , the housing includes an upper cover 1 and a base 2, and the upper cover 1 and the base 2 can be fixed by screws 4 to form a housing with a housing space. At the bottom of the housing, a guide rail is installed by setting a snap spring 3 to facilitate the movement of the power meter; a circuit accessory 5 is arranged inside the housing, and the circuit accessory 5 is used to fix the circuit components inside the housing, such as a fixed control board.

The parameter measurement terminals in this embodiment include: three-phase current input terminals, three-phase voltage input terminals, temperature input terminals, and leakage current input terminals.

Correspondingly, the control board is equipped with a microcontroller, a current sampling circuit, a voltage sampling circuit, and an electric energy metering circuit; among them, the three-phase current input terminal is connected to the current sampling circuit, and the three-phase voltage input terminal is connected to the voltage sampling circuit. Both the electric circuit and the voltage sampling circuit are connected with the electric energy metering circuit, and the electric energy metering circuit is connected with the microcontroller through the SPI data bus.

Because the STM32 series microcontrollers have the advantages of low price, high performance, and low power consumption, and the STM32F103 chip is also equipped with a wealth of peripheral device interfaces, such as USART, IIC, SPI, ADC, and GPI0 interfaces. Therefore, as shown in Figure 2 As shown, the microcontroller of this embodiment adopts the STM32F103 chip as the main control chip and an external FM24CL16B non-volatile memory chip as the EEPROM memory.

As shown in Figure 3-5, the current sampling circuit of this embodiment includes a-phase current sampling branch, b-phase current sampling branch and c-phase current sampling branch with the same circuit structure, and each phase current sampling branch includes current Transformer. Taking the a-phase current sampling branch as an example, the first end and the second end of the current transformer CT1 of the a-phase current sampling branch are respectively connected to the a-phase current input terminal among the three-phase current input terminals, and the current transformer CT1 The connectors I1p and I1N after the third terminal and the fourth section are respectively connected to the resistor R13 and the resistor R14 are connected to the microcontroller, and the third terminal and the fourth section of the current transformer CT1 are connected to the resistor R13 and the resistor R14. Resistor R7 and resistor R8 are connected in parallel, the parallel connection of resistor R7 and resistor R8 is grounded; capacitor C6 and capacitor C8 are also connected in parallel between resistor R13, resistor R14 and connectors I1p and I1N, and the parallel connection of capacitor C6 and capacitor C8 is grounded . Similarly, the circuit structure of the b-phase current sampling branch and the c-phase current sampling branch is the same as that of the a-phase current sampling branch, except that the values of the circuit components in each phase current sampling branch are different.

As shown in Figures 6-8, the voltage sampling circuit of this embodiment includes a-phase voltage sampling branch, b-phase voltage sampling branch and c-phase voltage sampling branch with the same circuit structure, and each phase voltage sampling branch includes a voltage Transformer. Taking the a-phase voltage sampling branch as an example, the first end and the second end of the voltage transformer PT1 of the a-phase voltage sampling branch are respectively connected to resistors R100 and R101, and then connected to the a-phase voltage input terminal among the three-phase voltage input terminals , the third terminal and the fourth section of the voltage transformer PT1 are respectively connected to the resistor R20 and the resistor R19, and the connectors VA and VAN are connected to the microcontroller, and the third terminal, the fourth section of the voltage transformer PT1 and the resistor R20 , Resistor R26 and resistor R25 are also connected in parallel between resistor R19, and the parallel connection of resistor R26 and resistor R25 is grounded; between resistor R20, resistor R19 and connector VA and VAN, capacitor C7 and capacitor C3, capacitor C7 and capacitor The parallel connection of C3 is connected to ground. Similarly, the circuit structure of the b-phase voltage sampling branch and the c-phase voltage sampling branch is the same as that of the a-phase voltage sampling branch, except that the values of the circuit components in each phase voltage sampling branch are different.

In this embodiment, the current transformer adopts ZMCT102 miniature current transformer, its rated input current is 5A, and its rated output current is 2.5raA; the voltage transformer adopts ZMPT107 miniature voltage transformer, its rated input current is 2mA, and its rated output current is 2mA.

As shown in Figure 9, the electric energy metering circuit of this embodiment uses the RN7302 chip as the three-phase electric energy metering chip, which is suitable for the application occasions of three-phase three-wire and three-phase four-wire. The RN7302 chip integrates multiple second-order sigma-delta- ADC (that is, ∑-△-ADC, an analog-to-digital converter), reference voltage circuit, and digital signal processing circuits for power, energy, effective value, power factor, and frequency measurement can measure the phases of each phase and the combined phase Active power, reactive power, apparent power, active energy and reactive energy can also measure the parameters of each phase current, voltage RMS, power factor, phase angle, frequency, etc. Power Meter Requirements.

In this embodiment, the power meter further includes: a communication interface arranged on the side of the casing and a remote communication circuit arranged on the control board, the communication interface is connected to the remote communication circuit, and the remote communication circuit is connected to the microcontroller.

As shown in Figure 12, the remote communication circuit of this embodiment includes a RS485 communication module and a GPRS communication module. The modules are connected together. Exemplarily, the GPRS communication module adopts the M590E GPRS module.

In this embodiment, the remote communication circuit adopts the MODBUS communication transmission protocol. Since the power meter is applied to the occasion of one-to-many and long-distance communication, on the one hand, the SN75176 half-duplex isolated RS485 bus transceiver chip is used to design the RS485 communication module. Realize stable and reliable data remote communication, and strong anti-interference ability; on the other hand, the GPRS communication module is used together to effectively realize the real-time monitoring and remote control of the power quality of the power meter.

Referring to Figures 10-11, the control board of this embodiment is also provided with a switching value input circuit and a switching value output circuit respectively connected to the microcontroller.

Referring to Fig. 10, the S1 end of the switch value input circuit is connected to the first end of the coupler OP3 after connecting the resistor R104, the public interface SG end of the switch value input circuit is connected to the second end of the coupler OP3, and the resistor R104, the coupler A diode D1 and a capacitor C28 are connected in series between the first end of the OP3 and the SG end and the second end of the coupler OP3, a capacitor C26 is connected in parallel between the third end and the fourth end of the coupler OP3, and the third end of the coupler OP3 is grounded. The fourth end of the coupler OP3 is connected to the switch connection terminal SwitchIN1 of the microcontroller; the S2 end of the switch input circuit is connected to the resistor R105 and then connected to the first end of the coupler OP4, and the public interface SG end of the switch input circuit is connected to the coupler The second end of OP4 is connected, a diode D2 and a capacitor C29 are connected in series between the resistor R105, the first end of the coupler OP4 and the SG end, and the second end of the coupler OP4, and between the third end and the fourth end of the coupler OP4 The capacitor C30 is connected in parallel, the third terminal of the coupler OP4 is grounded, and the fourth terminal of the coupler OP4 is connected to the switch terminal SwitchIN2 of the microcontroller; wherein, both the coupler OP3 and the coupler OP4 are TLP181 type transistor output optocouplers.

Referring to FIG. 11 , the switch value output circuit includes a first output branch and a second output branch with the same circuit structure. Taking the first output branch as an example, the resistor 102 of the first output branch is connected to the base of the triode Q3, the emitter of the triode Q3 is grounded, the collector of the triode is connected to the positive pole of the diode D3, the negative pole of the diode is grounded, and the positive pole of the diode D3 The negative pole is also connected to the first terminal and the second terminal of the switch K1, the third terminal of the switch K1 is connected to the fourth terminal and then connected to RL12, the fifth terminal of the switch K1 is connected to RL11, and the switch K1 is a HF3312FS ultra-small medium power relay , RL11 and RL12 are connected to the switching output terminals.

The power meter in this embodiment also includes a display screen and operation buttons arranged on the surface of the housing, the display screen is connected to the microcontroller, and the operation buttons are connected to the I/O port of the microcontroller.

Apparently, the power meter of this embodiment also includes a power supply connection terminal arranged on the side of the casing and a switching power supply arranged inside the casing; the power supply connection terminal is connected to the switching power supply, and the switching power supply is connected to the control board to supply power to the power meter. Among them, the input voltage of the switching power supply is 85-270VAC, and the output voltage is 12VDC, which can be applied to various application occasions of different power supply systems.

In a specific embodiment, as shown in Figure 1, this embodiment provides a multi-functional power meter, including: a housing; an LCD display and operation buttons arranged on the front of the housing; Power supply terminal, three-phase current input terminal, three-phase voltage input terminal, electric energy pulse output port, communication interface; switching power supply and control board installed inside the housing, power supply terminal connected to the switching power supply, switching power supply connected to the control board , to supply power for the entire power meter; LCD display, operation buttons, three-phase current input terminals, three-phase voltage input terminals, and communication interfaces are all electrically connected to the control board.

The control board is equipped with a current sampling circuit, a voltage sampling circuit, an electric energy metering circuit, a microcontroller, a switch input circuit, a switch output circuit, and a remote communication circuit; among them, the three-phase current input terminals are connected to the current sampling circuit, and the three-phase The voltage input terminal is connected to the voltage sampling circuit, the current sampling circuit and the voltage sampling circuit are connected to the electric energy metering circuit, the electric energy metering circuit is connected to the microcontroller through the SPI data bus, the switching value input circuit, the switching value output circuit, the remote communication circuit, the LCD The display screens are all connected with the microcontroller; the remote communication circuit is connected with the communication interface, and the operation keys are connected with the I/O port of the microcontroller.

The overall structure of the power meter proposed by the utility model is ingenious in design, convenient in disassembly, assembly, maintenance and replacement, low in cost, various in measurement electrical parameters, high in measurement accuracy, reasonable in structural design, convenient in installation, strong in safety, reliability and anti-interference , the power meter is an intelligent three-phase comprehensive power parameter monitoring instrument with programmable functions, automatic measurement, LCD liquid crystal display, power accumulation and digital remote communication. It can measure the three-phase AC power according to the linear relationship Converted to standardized digital quantities, integrating digitization, intelligence, and networking, to automate the measurement process and data analysis and processing, reduce human errors, and can partially replace power transmitters, electric energy meters, digital display instruments and data acquisition Devices and other instruments can effectively improve the integration degree, stability and reliability of power supply system parameter monitoring. The LCD display adopts liquid crystal display, which is convenient for observation and recording.

The multifunctional power meter proposed by the utility model adopts a modular design, which can adapt to the design requirements of a high-reliability multifunctional power monitoring meter. The power meter in this embodiment can communicate with a specific server by setting server information to realize data exchange and monitoring. Remote control has the characteristics of convenient installation, simple wiring, convenient maintenance, field programmable input parameters, complete functions, good versatility, high precision, fast processing speed, networked remote transmission of power grid operation data and instrument operation status, etc. It can directly replace conventional power transmitters, measuring and indicating instruments, electric energy metering instruments and related auxiliary units; as a front-end acquisition component of an advanced intelligent and digital power supply system, the power meter of this embodiment can be widely used in various Various control systems, substation automation, distribution network automation, community power monitoring, intelligent buildings and switch cabinets, and can complete the networking of different PLC and industrial control computer systems in the industry.

The above descriptions are only specific implementations of the present utility model. Under the above teaching of the present utility model, those skilled in the art can make other improvements or deformations on the basis of the above embodiments. Those skilled in the art should understand that the above specific description is only to better explain the purpose of the utility model, and the protection scope of the utility model should be based on the protection scope of the claims.

Claims (10)

1. A power meter, characterized in that, comprising: case; The parameter measurement terminal arranged on the side of the casing and the control mainboard arranged inside the casing, the parameter measurement terminal is connected to the control mainboard; The control mainboard is used for measuring electrical parameters. 2. The power meter according to claim 1, wherein the parameter measurement terminals include: three-phase current input terminals, three-phase voltage input terminals, temperature input terminals, and leakage current input terminals. 3. The power meter according to claim 2, wherein the control board is provided with a microcontroller, a current sampling circuit, a voltage sampling circuit, and an electric energy metering circuit; The three-phase current input terminal is connected to a current sampling circuit, the three-phase voltage input terminal is connected to a voltage sampling circuit, both the current sampling circuit and the voltage sampling circuit are connected to the electric energy metering circuit, and the electric energy metering circuit passes The SPI data bus connects the microcontroller. 4. The power meter according to claim 3, wherein the microcontroller is also connected to a non-volatile memory. 5. The power meter according to claim 3, characterized in that, The current sampling circuit includes a-phase current sampling branch, b-phase current sampling branch and c-phase current sampling branch with the same circuit structure, and each phase current sampling branch includes a current transformer; The voltage sampling circuit includes a-phase voltage sampling branch, b-phase voltage sampling branch and c-phase voltage sampling branch with the same circuit structure, and each phase voltage sampling branch includes a voltage transformer; The electric energy metering circuit adopts RN7302 chip as the three-phase electric energy metering chip. 6. The power meter according to claim 3, further comprising: a communication interface arranged on the side of the housing and a remote communication circuit arranged on the control board, the communication interface and the remote communication circuit connected, and the remote communication circuit is connected with the microcontroller. 7. The power meter according to claim 6, wherein the remote communication circuit adopts MODBUS communication transmission protocol. 8 . The power meter according to claim 3 , wherein the control board is further provided with a switching value input circuit and a switching value output circuit respectively connected to the microcontroller. 9. The power meter according to claim 3, further comprising: a display screen and operation buttons arranged on the surface of the casing, the display screen is connected to the microcontroller, and the operation buttons are connected to the The I/O port of the microcontroller. 10. The power meter according to any one of claims 1-9, further comprising: a power supply connection terminal arranged on the side of the casing and a switching power supply arranged inside the casing; The power supply connection terminal is connected to the switching power supply, and the switching power supply is connected to the control main board to supply power to the power meter.