An automatic switching circuit for three-phase four-wire and three-phase three-wire voltage lines for intelligent instruments

Abstract

The utility model discloses an automatic switching circuit for three-phase four-wire and three-phase three-wire voltage wiring systems for intelligent instruments, including a resistance voltage-dropping network module, a multi-way analog switch, a metering chip, a main controller, a button and a display, wherein the resistance voltage-dropping network module end is connected to the positive end of the metering chip, the resistance voltage-dropping network module is connected to the multi-way analog switch, the multi-way analog switch is connected to the negative end of the metering chip, the resistance voltage-dropping network module is used to connect the output power supply of three-phase four-wire or three-phase three-wire, the metering chip is connected to the main controller, and the main controller is connected to the multi-way analog switch, the button and the display. The utility model unifies the wiring of the three-phase four-wire and three-phase three-wire voltage wiring systems, simplifies production, reduces the circuit volume, greatly reduces costs, and is convenient for ready-made installation and subsequent upgrades.

Description

Technical Field

[0001] The utility model belongs to the field of three-phase intelligent instruments, and particularly relates to an automatic switching circuit for three-phase four-wire and three-phase three-wire voltage lines for intelligent instruments. Background Art

[0002] During the installation process of existing three-phase smart meters, multiple voltage wiring methods such as three-phase four-wire and three-phase three-wire are encountered. Since the voltage measurement inside the smart meter is based on the neutral line N phase voltage under the three-phase four-wire system, and the voltage measurement is based on the live line B phase voltage under the three-phase three-wire system, it is bound to result in the production of two smart meters that adapt to different wiring systems, increasing the cost of the smart meter itself. If the on-site installation environment has both three-phase four-wire and three-phase three-wire voltage wiring methods, it is easy to cause the meter to be incorrectly wired during the installation process. Utility Model Content

[0003] In order to solve the above technical problems, the utility model provides an automatic switching circuit between three-phase four-wire and three-phase three-wire voltage systems for intelligent instruments.

[0004] In order to solve the above technical problems, the utility model adopts the following technical solutions:

[0005] A three-phase four-wire and three-phase three-wire voltage line automatic switching circuit for intelligent instruments, comprising a resistance step-down network module, a multi-way analog switch, a metering chip, a main controller, a button and a display, wherein the resistance step-down network module end is connected to the positive end of the metering chip, the resistance step-down network module is connected to the multi-way analog switch, the multi-way analog switch is connected to the negative end of the metering chip, the resistance step-down network module is used to connect the output power supply of the three-phase four-wire or three-phase three-wire, the metering chip is connected to the main controller, and the main controller is connected to the multi-way analog switch, the button and the display.

[0006] The multi-way analog switch includes an A terminal, a B terminal, a C terminal, an AC terminal, a BC terminal and a CC terminal, wherein the AC terminal is connected to the switch AX and the switch AY, the AB terminal is connected to the switch BC and the switch BY, the AC terminal is connected to the switch XC and the switch XY, the AC terminal is used to output a voltage signal UAN, the AB terminal is used to output a voltage signal UBN, the CC terminal is used to output a voltage signal UCN, the A terminal is used to output a voltage signal V1, the B terminal is used to output a voltage signal V2, and the C terminal is used to output a voltage signal V3. The power supply terminal of the multi-way analog switch is connected to a DC power supply VCC, and the power ground, the negative power supply and the enable pin in the multi-way analog switch are connected to the signal ground.

[0007] The resistive step-down network module includes a UA phase step-down structure, a UB phase step-down structure, a UC phase step-down structure and an N phase step-down structure, wherein the UB phase step-down structure has two UB sub-phase step-down structures connected in parallel, and the N phase step-down structure has three N sub-phase step-down structures connected in parallel, wherein one UB sub-phase step-down structure is connected to switch AY and switch BY in a multi-way analog switch, and another UB sub-phase step-down structure is connected to switch CY in a plurality of analog switches, and the three N sub-phase step-down structures are respectively connected to switch AX, switch BX and switch CX in the multi-way analog switch.

[0008] The UA phase step-down structure includes a resistor RA1, a resistor RA2, a resistor RA3, a resistor RA4 and a resistor R1 which are connected in series in sequence, and the resistor R1 is grounded.

[0009] In the UB phase step-down structure, one UB sub-phase step-down structure includes a resistor RB11, a resistor RB12, a resistor RB13, a resistor RB14 and a resistor R2 connected in series in sequence, and the resistor R2 is grounded. Another UB sub-phase step-down structure includes a resistor RB21, a resistor RB22, a resistor RB23, a resistor RB24 and a resistor R3 connected in series in sequence, and the resistor R2 is grounded. The resistor RB11 is connected to the resistor RB21, the resistor RB14 is connected to the switch AY and the switch BY, and the resistor R24 ​​is connected to the switch XY.

[0010] The UC phase voltage reduction structure includes a resistor RC1, a resistor RC2, a resistor RC2, a resistor RC2 and a resistor R4 which are connected in series in sequence.

[0011] In the N-phase step-down structure, the first N-sub-phase step-down structure includes a resistor RAN1, a resistor RAN2, a resistor RAN3, a resistor RAN4 and a resistor R5 connected in series in sequence, the resistor RAN4 is connected to the switch AX, and the resistor R5 is grounded; the second N-sub-phase step-down structure includes a resistor RBN1, a resistor RBN2, a resistor RBN3, a resistor RBN4 and a resistor R6 connected in series in sequence, the resistor RBN4 is connected to the switch BX, and the resistor R6 is grounded; the third N-sub-phase step-down structure includes a resistor RCN1, a resistor RCN2, a resistor RCN3, a resistor RCN4 and a resistor R7 connected in series in sequence, the resistor RCN4 is connected to the switch CX, and the resistor R7 is grounded.

[0012] Compared with the prior art, the utility model has the following beneficial technical effects:

[0013] The input voltage is stepped down through the resistor network step-down module, and then controlled by the main controller and metering chip, as well as the control of the multi-channel analog switch, which can effectively achieve the unification of the wiring of the three-phase four-wire system and the three-phase three-wire system, simplify production, reduce circuit size, significantly reduce costs, and facilitate ready-made installation and subsequent upgrades. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of the principle framework of the utility model;

[0015] Figure 2 This is a schematic diagram of the connection principle between the resistor network step-down module and the multi-channel analog switch in the utility model. DETAILED DESCRIPTION

[0016] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0017] In the description of the present utility model, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like are involved, the orientation or position relationship indicated is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present utility model and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present utility model, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0018] In the description of the present utility model, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection. It can be a mechanical connection or an electrical connection. It can be directly connected or indirectly connected through an intermediate medium. It can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0019] refer to Figure 1 and 2As shown, an automatic switching circuit for three-phase four-wire and three-phase three-wire voltage lines for intelligent instruments includes a resistor voltage-drop network module, a multi-way analog switch, a metering chip, a main controller, a button and a display. The resistor voltage-drop network module end is connected to the positive end of the metering chip, the resistor voltage-drop network module is connected to the multi-way analog switch, the multi-way analog switch is connected to the negative end of the metering chip, the resistor voltage-drop network module is used to connect the output power supply of three-phase four-wire or three-phase three-wire, the metering chip is connected to the main controller, the main controller is connected to the multi-way analog switch, the button and the display, the display is used to display the current state, and can input parameters, such as setting the current state to three-phase four-wire or three-phase three-wire. When the external voltage system is input with three-phase four-wire, the voltages UA, UB, and UC are reduced to smaller voltage signals VA1, VB1, and VC1 through the resistor step-down network module and enter the positive terminal of the metering chip. The voltage UN is reduced to smaller signals VAN1, VBN1, and VCN1 through the resistor step-down network module and enter the multi-way analog switch. The main controller controls the multi-way analog switch to enter the negative terminal of the metering chip based on the UN sampling signal. When the external voltage system is input with three-phase three-wire, the voltages UA and UC are reduced to smaller signals VA1 and VC1 through the resistor step-down network module and enter the positive terminal of the metering chip. The voltage UB is reduced to small signals VB1 and VB2 through the resistor step-down network module and enter the multi-way analog switch. The main controller controls the multi-way analog switch to enter the negative terminal of the metering chip based on the UB sampling signal.

[0020] The multi-channel analog switch is selected as a three-channel two-choice analog switch, including an A terminal, a B terminal, a C terminal, an AC terminal, a BC terminal and a CC terminal, wherein the AC terminal is connected to the switch AX and the switch AY, the AB terminal is connected to the switch BC and the switch BY, the AC terminal is connected to the switch XC and the switch XY, the AC terminal is used to output a voltage signal UAN, the AB terminal is used to output a voltage signal UBN, the CC terminal is used to output a voltage signal UCN, the A terminal is used to output a voltage signal V1, the B terminal is used to output a voltage signal V2, and the C terminal is used to output a voltage signal V3. The power supply terminal of the multi-channel analog switch is connected to a DC power supply VCC, and the power ground, the negative power supply and the enable pin in the multi-channel analog switch are connected to the signal ground.

[0021] The resistive step-down network module includes a UA phase step-down structure, a UB phase step-down structure, a UC phase step-down structure and an N phase step-down structure, wherein the UB phase step-down structure has two UB sub-phase step-down structures connected in parallel, and the N phase step-down structure has three N sub-phase step-down structures connected in parallel, wherein one UB sub-phase step-down structure is connected to switch AY and switch BY in a multi-way analog switch, and another UB sub-phase step-down structure is connected to switch CY in a plurality of analog switches, and the three N sub-phase step-down structures are respectively connected to switch AX, switch BX and switch CX in the multi-way analog switch.

[0022] The UA phase step-down structure includes a resistor RA1, a resistor RA2, a resistor RA3, a resistor RA4 and a resistor R1 which are connected in series in sequence, and the resistor R1 is grounded.

[0023] In the UB phase step-down structure, one UB sub-phase step-down structure includes a resistor RB11, a resistor RB12, a resistor RB13, a resistor RB14 and a resistor R2 connected in series in sequence, and the resistor R2 is grounded. Another UB sub-phase step-down structure includes a resistor RB21, a resistor RB22, a resistor RB23, a resistor RB24 and a resistor R3 connected in series in sequence, and the resistor R2 is grounded. The resistor RB11 is connected to the resistor RB21, the resistor RB14 is connected to the switch AY and the switch BY, and the resistor R24 ​​is connected to the switch XY.

[0024] The UC phase voltage reduction structure includes a resistor RC1, a resistor RC2, a resistor RC2, a resistor RC2 and a resistor R4 which are connected in series in sequence.

[0025] In the N-phase step-down structure, the first N-sub-phase step-down structure includes a resistor RAN1, a resistor RAN2, a resistor RAN3, a resistor RAN4 and a resistor R5 connected in series in sequence, the resistor RAN4 is connected to the switch AX, and the resistor R5 is grounded; the second N-sub-phase step-down structure includes a resistor RBN1, a resistor RBN2, a resistor RBN3, a resistor RBN4 and a resistor R6 connected in series in sequence, the resistor RBN4 is connected to the switch BX, and the resistor R6 is grounded; the third N-sub-phase step-down structure includes a resistor RCN1, a resistor RCN2, a resistor RCN3, a resistor RCN4 and a resistor R7 connected in series in sequence, the resistor RCN4 is connected to the switch CX, and the resistor R7 is grounded.

[0026] When the external voltage system is input with three-phase four-wire, the voltage UA, UB, UC is reduced to small signals VA1, VB1, VC1 through the resistor step-down network module and enters the positive terminal of the metering chip. The voltage UN is reduced to small signals VAN1, VBN1, VCN1 through the resistor step-down network module and enters the multi-channel analog switch. After the operator operates the buttons and observes the display to set the smart meter to three-phase four-wire, the main controller connects AX-AC, BX-BC, CX-CC in the multi-channel analog switch by pulling down the V1, V2, V3 control signals. At this time, UAN, UBN, UCN enters the negative terminal of the metering chip; when the external voltage system is input with three-phase three-wire, the voltages UA and UC are reduced to small signals VA1 and VC1 through the resistor network and enter the positive terminal of the metering chip, and the voltage UB is reduced to small signals VB1 and VB2 through the resistor voltage-dropping network and enters the multi-channel analog switch. After the operator operates the buttons and observes the display to set the smart meter to a three-phase three-wire system, the main controller connects AY-AC, BY-BC, and CY-CC in the multi-channel analog switch by pulling up the V1, V2, and V3 control signals. At this time, UAN and UCN based on the UB sampling signal enter the negative terminal of the metering chip.

[0027] It should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent substitutions for some of the technical features therein. However, any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An automatic switching circuit for three-phase four-wire and three-phase three-wire voltage lines for intelligent instruments, characterized in that: It includes a resistance step-down network module, a multi-way analog switch, a metering chip, a main controller, buttons and a display. The resistance step-down network module end is connected to the positive end of the metering chip, the resistance step-down network module is connected to the multi-way analog switch, the multi-way analog switch is connected to the negative end of the metering chip, the resistance step-down network module is used to connect a three-phase four-wire or three-phase three-wire output power supply, the metering chip is connected to the main controller, and the main controller is connected to the multi-way analog switch, the buttons and the display.

2. The three-phase four-wire and three-phase three-wire voltage line automatic switching circuit for intelligent meters according to claim 1 is characterized in that: The multi-way analog switch includes an A terminal, a B terminal, a C terminal, an AC terminal, a BC terminal and a CC terminal, wherein the AC terminal is connected to the switch AX and the switch AY, the AB terminal is connected to the switch BC and the switch BY, the AC terminal is connected to the switch XC and the switch XY, the AC terminal is used to output a voltage signal UAN, the AB terminal is used to output a voltage signal UBN, the CC terminal is used to output a voltage signal UCN, the A terminal is used to output a voltage signal V1, the B terminal is used to output a voltage signal V2, and the C terminal is used to output a voltage signal V3. The power supply terminal of the multi-way analog switch is connected to a DC power supply VCC, and the power ground, the negative power supply and the enable pin in the multi-way analog switch are connected to the signal ground.

3. The three-phase four-wire and three-phase three-wire voltage line automatic switching circuit for intelligent meters according to claim 2 is characterized in that: The resistive step-down network module includes a UA phase step-down structure, a UB phase step-down structure, a UC phase step-down structure and an N phase step-down structure, wherein the UB phase step-down structure has two UB sub-phase step-down structures connected in parallel, and the N phase step-down structure has three N sub-phase step-down structures connected in parallel, wherein one UB sub-phase step-down structure is connected to switch AY and switch BY in a multi-way analog switch, and another UB sub-phase step-down structure is connected to switch CY in a plurality of analog switches, and the three N sub-phase step-down structures are respectively connected to switch AX, switch BX and switch CX in the multi-way analog switch.

4. The three-phase four-wire and three-phase three-wire voltage line automatic switching circuit for intelligent meters according to claim 3 is characterized in that: The UA phase step-down structure includes a resistor RA1, a resistor RA2, a resistor RA3, a resistor RA4 and a resistor R1 which are connected in series in sequence, and the resistor R1 is grounded.

5. The three-phase four-wire and three-phase three-wire voltage automatic switching circuit for intelligent meters according to claim 4, characterized in that: In the UB phase step-down structure, one UB sub-phase step-down structure includes a resistor RB11, a resistor RB12, a resistor RB13, a resistor RB14 and a resistor R2 connected in series in sequence, and the resistor R2 is grounded. Another UB sub-phase step-down structure includes a resistor RB21, a resistor RB22, a resistor RB23, a resistor RB24 and a resistor R3 connected in series in sequence, and the resistor R2 is grounded. The resistor RB11 is connected to the resistor RB21, the resistor RB14 is connected to the switch AY and the switch BY, and the resistor R24 ​​is connected to the switch XY.

6. The three-phase four-wire and three-phase three-wire voltage line automatic switching circuit for intelligent meters according to claim 5, characterized in that: The UC phase voltage reduction structure includes a resistor RC1, a resistor RC2, a resistor RC2, a resistor RC2 and a resistor R4 which are connected in series in sequence.

7. The three-phase four-wire and three-phase three-wire voltage line automatic switching circuit for intelligent meters according to claim 6, characterized in that: In the N-phase step-down structure, the first N-sub-phase step-down structure includes a resistor RAN1, a resistor RAN2, a resistor RAN3, a resistor RAN4 and a resistor R5 connected in series in sequence, the resistor RAN4 is connected to the switch AX, and the resistor R5 is grounded; the second N-sub-phase step-down structure includes a resistor RBN1, a resistor RBN2, a resistor RBN3, a resistor RBN4 and a resistor R6 connected in series in sequence, the resistor RBN4 is connected to the switch BX, and the resistor R6 is grounded; the third N-sub-phase step-down structure includes a resistor RCN1, a resistor RCN2, a resistor RCN3, a resistor RCN4 and a resistor R7 connected in series in sequence, the resistor RCN4 is connected to the switch CX, and the resistor R7 is grounded.

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