Three-phase resistance-capacitance power supply circuit based on three-path manganese-copper isolation and electric energy meter

Abstract

The utility model relates to a kind of three-phase resistance-capacitance power supply circuit and electric energy meter based on three-way manganese copper isolation, the circuit includes three-phase alternating current, power supply chip, three-way resistance-capacitance power taking branch and common rectifier filter circuit;Three-phase alternating current exports metering power supply by three-way resistance-capacitance power taking branch, the three-phase alternating current includes A phase, B phase, C phase live wire and neutral line N, three-way resistance-capacitance power taking branch is connected between one phase live wire and neutral line, when neutral line N is positive, provides metering power supply for the metering chip of corresponding phase by resistance-capacitance power taking branch;Common rectifier filter circuit inputs three-way resistance-capacitance power taking branch with output direct current;Metering power supply exports stabilized power supply by power supply chip, and the stabilized power supply is powered to metering chip by the manganese copper shunt ware of electric energy meter.The three-way manganese copper independent sampling structure in the application multiplex electric energy meter, realize the electrical isolation between three-way power supply, effectively block the mutual coupling of phase voltage fluctuation, harmonic interference or fault current.

Description

Technical Field

[0001] This utility model relates to the field of power supply technology for electricity meters, specifically to a three-phase RC power supply circuit and an electricity meter based on three-way manganese copper isolation. Background Technology

[0002] With the deepening of smart grid construction, three-phase four-wire smart meters, as core terminal equipment for power metering, load monitoring, and remote fee control in distribution substations, directly affect the stability of the electricity information collection system due to their operational reliability. Currently, low- and mid-range smart meters generally use a resistor-capacitor (RC) step-down power supply to power their internal circuits. This solution is low-cost, simple in structure, and requires no transformer. Existing technologies mostly employ a single-phase half-wave or full-wave RC power supply method, that is, connecting a resistor and capacitor between a phase line and the neutral line for step-down rectification to obtain the required DC operating voltage.

[0003] However, when a phase of the power supply fails, voltage drops, or line maintenance occurs, the power supply immediately loses power, causing the meter to malfunction and data to be interrupted, which seriously affects the continuity of remote meter reading and fee control functions. At the same time, single-point power supply has low reliability and weak anti-interference ability. Under complex operating conditions such as severe load fluctuations, three-phase imbalance, or the presence of harmonic pollution, the power output is unstable. Utility Model Content

[0004] To address the aforementioned problems, this utility model provides a three-phase RC power supply circuit based on three-way manganese copper isolation for powering a three-phase smart energy meter. The circuit includes three-phase AC power, a power chip, three RC power supply branches, and a common rectifier and filter circuit; wherein: The three-phase AC power is output as metering power through three resistor-capacitor power supply branches. The three-phase AC power includes A-phase, B-phase, C-phase live wires and neutral line N. The three resistor-capacitor power supply branches are connected between one live wire and the neutral line. When the neutral line N is positive, the resistor-capacitor power supply branches provide metering power to the metering chip of the corresponding phase. The common rectifier and filter circuit includes a rectifier bridge and a ferrite bead, and the common rectifier and filter circuit supplies the output DC power to the energy meter MCU; The metering power supply outputs a regulated power supply through the power chip, and the regulated power supply powers the metering chip through the manganese copper shunt of the energy meter.

[0005] Preferably, the independent RC power supply branch includes: the three-phase live wires are connected in sequence to a Zener diode, a wire-wound resistor, and a safety capacitor; the other end of the safety capacitor is connected to the neutral line N through a TVS diode; the other end of the Zener diode is connected to the positive terminal of a half-wave rectifier diode; the negative terminal of the half-wave rectifier diode outputs the metering power supply; and an electrolytic capacitor is also connected between the three-phase live wires and the metering power supply.

[0006] Based on the above scheme, the three independent resistor-capacitor power supply branches include: A-phase branch: The A-phase live wire is connected in sequence to the first Zener diode, the first wire-wound resistor, and the first safety capacitor. The other end of the first safety capacitor is connected to the neutral line N through the first TVS diode. The other end of the first Zener diode is connected to the positive terminal of the first half-wave rectifier diode. The negative terminal of the first half-wave rectifier diode outputs the first metering power supply. B-phase branch: The B-phase live wire is connected in sequence to the second Zener diode, the second wire-wound resistor, and the second safety capacitor. The other end of the second safety capacitor is connected to the neutral line N through the second TVS diode. The other end of the second Zener diode is connected to the positive terminal of the second half-wave rectifier diode. The negative terminal of the second half-wave rectifier diode outputs the second metering power supply. C-phase branch: The C-phase live wire is connected in sequence to the third Zener diode, the third wire-wound resistor, and the third safety capacitor. The other end of the third safety capacitor is connected to the neutral line N through the third TVS diode. The other end of the third Zener diode is connected to the positive terminal of the third half-wave rectifier diode. The negative terminal of the third half-wave rectifier diode outputs the third metering power supply.

[0007] Specifically, the first safety capacitor and the second safety capacitor are respectively connected to the first rectifier bridge, the third safety capacitor is connected to the second rectifier bridge, the outputs of the first rectifier bridge and the second rectifier bridge are connected to a ferrite bead, and the other end of the ferrite bead outputs a power supply voltage to power the energy meter MCU. The power supply voltage is also connected to a fourth electrolytic capacitor, and the fourth electrolytic capacitor is connected in parallel with the ceramic capacitor.

[0008] Based on the above scheme, the power chip includes a first LDO power supply, a second LDO power supply, and a third LDO power supply. The first metering power supply inputs the first LDO power supply and outputs a first regulated power supply. The second metering power supply inputs the second LDO power supply and outputs a second regulated power supply. The third metering power supply inputs the third LDO power supply and outputs a third regulated power supply.

[0009] Specifically, a fourth TVS diode is connected between the negative DC terminal and the positive DC terminal of the first rectifier bridge and the second rectifier bridge, respectively.

[0010] On the other hand, this application also provides an energy meter, including a three-phase RC power supply circuit as described above.

[0011] Compared with the prior art, the beneficial effects of this utility model are as follows: 1. Through the three-phase RC power supply design, the energy meter can independently draw power from multiple phases, so that when any phase is de-energized, the remaining phases can still power the metering chip or MCU, thereby enabling the energy meter to continue to work under single-phase or two-phase power failure, significantly improving power supply reliability and phase failure operation capability. 2. The three independent sampling structures of manganese copper in the energy meter are reused to achieve electrical isolation between the three power supplies, effectively blocking the mutual coupling of phase voltage fluctuations, harmonic interference or fault current, avoiding the impact of single-phase abnormalities on other phase metering circuits, and greatly improving the anti-interference capability of the multi-phase metering system. 3. TSV transistors are configured at the input of each phase for transient protection to quickly suppress transient high voltages such as lightning strikes and switching surges. The metering power supply is regulated by an LDO and then supplied to the metering chip to provide a low-noise, highly stable DC power supply, thus balancing safety in strong electromagnetic environments with the power purity required for high-precision metering. 4. The circuit of this application only uses common components such as diodes, Zener diodes, capacitors, and resistors. The circuit structure is simple, low in cost, and highly integrated, and can effectively power the electricity meter. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the overall circuit structure of this utility model; Figure 2 This is a schematic diagram of the circuit structure of the output metering power supply of this utility model; Figure 3 This is a circuit diagram of the step-down power chip of this utility model. Detailed Implementation

[0013] The present invention will be further described below with reference to the accompanying drawings: In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in this utility model can be understood according to the specific circumstances.

[0014] like Figure 1 As shown, this application provides a three-phase RC power supply circuit based on three-way manganese copper isolation for powering a three-phase smart energy meter. The circuit includes three-phase AC power, a power chip, three RC power supply branches, and a common rectifier and filter circuit; wherein: The three-phase AC power is output as metering power through three resistor-capacitor power supply branches. The three-phase AC power includes A-phase, B-phase, C-phase live wires and neutral line N. The three resistor-capacitor power supply branches are connected between one live wire and the neutral line. When the neutral line N is positive, the resistor-capacitor power supply branches provide metering power to the metering chip of the corresponding phase. The independent RC power supply branch includes: three-phase live wires connected in sequence to a Zener diode, a wire-wound resistor, and a safety capacitor. The other end of the safety capacitor is connected to the neutral line N through a TVS diode. The other end of the Zener diode is connected to the positive terminal of a half-wave rectifier diode. The negative terminal of the half-wave rectifier diode outputs the metering power supply. An electrolytic capacitor is also connected between the three-phase live wires and the metering power supply.

[0015] like Figure 2 As shown, the three independent resistor-capacitor power supply branches in this embodiment specifically include: A-phase branch: The A-phase live wire LA is connected in sequence to the first Zener diode D2, the first winding resistor R1, and the first safety capacitor C1. The other end of C1 is connected to the neutral line N through the first TVS diode D3. The other end of D2 is connected to the positive terminal of D1. The negative terminal of D1 outputs the first metering power supply VDD5.6A. The first electrolytic capacitor E1 is connected between LA and VDD5.6A.

[0016] B-phase branch: The B-phase live wire LB is connected in sequence to the second Zener diode D5, the second winding resistor R2, and the second safety capacitor C2. The other end of C2 is connected to the neutral line N through the second TVS diode D7. The other end of D5 is connected to the positive terminal of the second half-wave rectifier diode D4. The negative terminal of D4 outputs the second metering power supply VDD5.6B. The second electrolytic capacitor E2 is connected between LB and VDD5.6B.

[0017] C-phase branch: The C-phase live wire LC is connected in sequence to the third Zener diode D10, the third winding resistor R3, and the third safety capacitor C3. The other end of C3 is connected to the neutral line N through the third TVS diode D12. The other end of D10 is connected to the positive terminal of the third half-wave rectifier diode D9. The negative terminal of D9 outputs the third metering power supply VDD5.6C. The third electrolytic capacitor E3 is connected between LC and VDD5.6C.

[0018] In the above circuit, a TVS diode is used instead of the varistor in the existing technology. TVS diodes have extremely fast response and precise clamping, and can absorb transient high voltage pulses, quickly suppress transient high voltage, and protect the downstream circuits. Wire-wound resistors and safety capacitors are used to achieve voltage reduction through resistance and capacitance.

[0019] According to this embodiment, an AC sine wave is rectified into pulsating DC by a half-wave rectifier diode, and an electrolytic capacitor converts the pulsating DC into a smooth DC output, thereby outputting a metering power supply.

[0020] like Figure 2 As shown, the shared rectifier and filter circuit includes a first rectifier bridge, a second rectifier bridge, and a filter capacitor. The three-phase RC power supply circuit outputs DC power through the shared rectifier and filter circuit, and then inputs the DC power into the DC-DC step-down chip to power the MCU of the energy meter.

[0021] Specifically, C1 and C2 in the independent RC power supply branch are connected to the first rectifier bridge D6, and C3 is connected to the second rectifier bridge D8. The outputs of D6 and D8 are connected to the ferrite bead LD1. The other end of LD1 outputs a power supply voltage of 36V. The power supply voltage is output as 3.3V by the DC-DC step-down chip to power the MCU of the energy meter. The power supply voltage is also connected to the fourth electrolytic capacitor C5, which is connected in parallel with the ceramic capacitor C4. The negative DC terminal and the positive DC terminal of D6 and D8 are connected to the fourth TVS diode D13. The circuit also includes a fourth Zener diode D11 and a fifth Zener diode D14. D14 and D11 are connected in series and then in parallel with D13.

[0022] The circuit described above uses two Zener diodes connected in series. When the voltage in the circuit exceeds a certain safety threshold, the Zener diodes will enter the breakdown region and conduct, sharing the excess voltage and thus protecting other sensitive components from damage. Using two Zener diodes in series can increase the shared voltage, ensure the power of the Zener diodes, and prevent excessive power consumption and severe heat generation of the Zener diodes when the downstream is unloaded. C4 and C5 are used for filtering and energy storage, and the ferrite bead is connected in series with the output power supply to filter out high-frequency noise from the power supply and prevent interference with the operation of downstream chips.

[0023] In this embodiment, the metering power supply outputs a regulated power supply through a power chip, and the regulated power supply powers the metering chip through a manganese copper shunt.

[0024] like Figure 3 As shown, the metering power supply is regulated to 3.3V by a power chip to power the A / B / C metering chips. The power chip includes a first LDO power supply U1, a second LDO power supply U2, and a third LDO power supply U3. VDD5.6A is input to U1, and U1 outputs the first regulated power supply AVCC; VDD5.6B is input to U2, and U2 outputs the second regulated power supply BVCC; VDD5.6C is input to U3, and U3 outputs the third regulated power supply CVCC; AVCC, BVCC, and CVCC respectively power the three metering chips.

[0025] The circuit outputs three power supply circuits that power the metering chip, each with its own ground wires AGND, BGND, and CGND. U1 is connected to AGND, U2 to BGND, and U3 to CGND. A first capacitor C6 and a second capacitor C7 are connected in parallel between AVCC and AGND, and a third capacitor C8 is connected between VDD5.6A and AGND. A fourth capacitor C11 and a fifth capacitor C9 are connected in parallel between BVCC and BGND, and a sixth capacitor C10 is connected between VDD5.6B and BGND. A seventh capacitor C12 and an eighth capacitor C13 are connected in parallel between CVCC and CGND, and a ninth capacitor C14 is connected between VDD5.6C and CGND.

[0026] The circuit works as follows: When LA is positive and N is negative, the current flows out of LA, passing through D2, R1, C1, D6, LD1, C5, and D8 in sequence, finally returning to N. When LA is negative and N is positive, the current starts from N, passing through D8, LD1, C5, D6, C1, R1, D1, and E1 in sequence, finally outputting VDD5.6A. Therefore, when N is positive, the circuit outputs VDD5.6A, which is then stepped down by U1 to provide power to the metering chip via AVCC.

[0027] When LB is positive and N is negative, the current flows out of LB, passing through D5, R2, C2, D6, LD1, C5, and D8 in sequence, finally returning to N. When LB is negative and N is positive, the current starts from N, passing through D8, LD1, C5, D6, C2, R2, D4, and E2 in sequence, finally outputting VDD5.6B. Therefore, when N is positive, the circuit outputs VDD5.6B, which is then stepped down through U2 to BVCC to power the metering chip.

[0028] When LC is positive and N is negative, the current flows out of LC, passing through D10, R3, C3, D8, LD1, C5, and D8 in sequence, finally returning to N. When LC is negative and N is positive, the current starts from N, passing through D8, LD1, C5, D8, C3, R3, D9, and E3 in sequence, finally outputting VDD5.6C. Therefore, when N is positive, the circuit outputs VDD5.6C, which is then stepped down through U3 to provide power to the metering chip via CVCC.

[0029] On the other hand, this application also provides an energy meter, including the three-phase RC power supply circuit as described above. The circuit utilizes the electrical isolation characteristics of the existing three-channel manganese copper independent sampling structure in the energy meter. The regulated power supplies AVCC, BVCC and CVCC respectively supply power to the A / B / C metering chips through the three manganese copper channels. This circuit solves the problems of low reliability, poor anti-interference ability and easy power loss due to phase failure in traditional single-phase power supplies.

[0030] The foregoing has shown and described the basic principles and main features of this utility model. It is obvious to those skilled in the art that this utility model is not limited to the details of the above exemplary embodiments. Therefore, the embodiments should be regarded as exemplary and non-limiting. The scope of this utility model is defined by the appended claims rather than the foregoing description. Therefore, it is intended to include all changes that fall within the meaning and scope of the equivalents of the claims within this utility model.

[0031] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A three-phase RC power supply circuit based on three-way manganese copper isolation, characterized in that, The circuit is used to power a three-phase smart energy meter and includes a three-phase AC power supply, a power chip, three resistor-capacitor power supply branches, and a common rectifier and filter circuit; wherein: The three-phase AC power is output as metering power through three resistor-capacitor power supply branches. The three-phase AC power includes A-phase, B-phase, C-phase live wires and neutral line N. The three resistor-capacitor power supply branches are connected between one live wire and the neutral line. When the neutral line N is positive, the resistor-capacitor power supply branches provide metering power to the metering chip of the corresponding phase. The common rectifier and filter circuit includes a rectifier bridge and a ferrite bead, and the common rectifier and filter circuit supplies the output DC power to the energy meter MCU; The metering power supply outputs a regulated power supply through the power chip, and the regulated power supply powers the metering chip through the manganese copper shunt of the energy meter.

2. The three-phase RC power supply circuit based on three-way manganese copper isolation according to claim 1, characterized in that, The independent RC power supply branch includes: three-phase live wires connected in sequence to a Zener diode, a wire-wound resistor, and a safety capacitor. The other end of the safety capacitor is connected to the neutral line N through a TVS diode. The other end of the Zener diode is connected to the positive terminal of a half-wave rectifier diode. The negative terminal of the half-wave rectifier diode outputs the metering power supply. An electrolytic capacitor is also connected between the three-phase live wires and the metering power supply.

3. The three-phase RC power supply circuit based on three-way manganese copper isolation according to claim 2, characterized in that, The three independent resistor-capacitor power supply branches include: A-phase branch: The A-phase live wire is connected in sequence to the first Zener diode, the first wire-wound resistor, and the first safety capacitor. The other end of the first safety capacitor is connected to the neutral line N through the first TVS diode. The other end of the first Zener diode is connected to the positive terminal of the first half-wave rectifier diode. The negative terminal of the first half-wave rectifier diode outputs the first metering power supply. B-phase branch: The B-phase live wire is connected in sequence to the second Zener diode, the second wire-wound resistor, and the second safety capacitor. The other end of the second safety capacitor is connected to the neutral line N through the second TVS diode. The other end of the second Zener diode is connected to the positive terminal of the second half-wave rectifier diode. The negative terminal of the second half-wave rectifier diode outputs the second metering power supply. C-phase branch: The C-phase live wire is connected in sequence to the third Zener diode, the third wire-wound resistor, and the third safety capacitor. The other end of the third safety capacitor is connected to the neutral line N through the third TVS diode. The other end of the third Zener diode is connected to the positive terminal of the third half-wave rectifier diode. The negative terminal of the third half-wave rectifier diode outputs the third metering power supply.

4. The three-phase RC power supply circuit based on three-way manganese copper isolation according to claim 3, characterized in that, The first safety capacitor and the second safety capacitor are respectively connected to the first rectifier bridge, and the third safety capacitor is connected to the second rectifier bridge. The outputs of the first rectifier bridge and the second rectifier bridge are connected to a ferrite bead. The other end of the ferrite bead outputs a power supply voltage to power the energy meter MCU. The power supply voltage is also connected to a fourth electrolytic capacitor, which is connected in parallel with a ceramic capacitor.

5. The three-phase RC power supply circuit based on three-way manganese copper isolation according to claim 3, characterized in that, The power chip includes a first LDO power supply, a second LDO power supply, and a third LDO power supply. The first metering power supply inputs the first LDO power supply and outputs a first regulated power supply. The second metering power supply inputs the second LDO power supply and outputs a second regulated power supply. The third metering power supply inputs the third LDO power supply and outputs a third regulated power supply.

6. The three-phase RC power supply circuit based on three-way manganese copper isolation according to claim 4, characterized in that, A fourth TVS diode is connected between the negative DC terminal and the positive DC terminal of the first rectifier bridge and the second rectifier bridge, respectively.

7. An electricity meter, characterized in that, Includes the three-phase RC power supply circuit as described in any one of claims 1-6.

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