Low-power-consumption standby circuit of external circuit breaker of electric energy meter

Abstract

The utility model is suitable for the technical field of electric meter circuits, and relates to a low-power standby circuit of an external circuit breaker of an electric energy meter, which comprises an electromagnetic compatibility and rectification circuit, a linear step-down power supply circuit, a bus switch circuit, a DC / DC power supply circuit, a voltage-stabilized power supply circuit and an MCU control circuit. The electromagnetic compatibility and rectification circuit is respectively in communication connection with the linear step-down power supply circuit and the bus switch circuit, the bus switch circuit is further respectively in communication connection with the DC / DC power supply circuit and the MCU control circuit, the linear step-down power supply circuit, the voltage-stabilized power supply circuit and the MCU control circuit are sequentially in communication connection, and the DC / DC power supply circuit is further in communication connection with the voltage-stabilized power supply circuit. The external circuit breaker is simple in structure, powerful in function, small in occupied space and low in cost while low-power-consumption standby of the external circuit breaker circuit of the electric energy meter is achieved.

Description

Technical Field

[0001] The utility model belongs to the technical field of electric meter circuits, and in particular relates to a low-power standby circuit of an external circuit breaker of an electric energy meter. Background Art

[0002] State Grid Corporation of China and China Southern Power Grid Corporation clearly require that after the control unit is opened and closed, the steady-state current consumed by each phase line should be less than 0.2mA, in order to make the power consumption of the external circuit breaker of the energy meter not counted when the energy meter is unloaded. In order to achieve such low power consumption, the low-power standby circuit of the external circuit breaker of the energy meter on the market generally adopts MOS tubes or triodes, which are realized by closing the busbar in a two-by-two combination. This method requires at least two high-voltage thyristors and a string of step-down resistors to cooperate with each other for control. The circuit logic is complex, and there are many devices in the circuit. Once one of the devices fails, it will affect the entire control circuit. Moreover, they are all high-voltage devices, and the electrical clearance and creepage distance must be strictly controlled. The price of two high-voltage thyristors is also relatively high. Therefore, there are disadvantages such as complex circuits, many components, large circuit board area, and high cost.

[0003] The patent application with publication number CN204188687U provides a load switch pre-circuit, which includes a rectifier circuit and a switch circuit for controlling the on / off of a DC / DC power module circuit. One end of the rectifier circuit is connected to the circuit breaker, and the other end is connected to the DC / DC power module through the switch circuit. The switch circuit includes a first control element and a second control element for on / off, and the first and second control elements are triodes or MOS tubes. This patent also uses a method of using MOS tubes or triodes to close the bus, which has the same disadvantages as the prior art.

[0004] Therefore, how to provide a low-power standby circuit for an external circuit breaker of an electric energy meter with a simple circuit, low cost and small space occupation is an urgent problem to be solved by personnel in this technical field. Utility Model Content

[0005] In view of the deficiencies in the prior art, the purpose of the utility model is to provide a low-power standby circuit for an external circuit breaker of an electric energy meter, so as to solve the problems in the prior art that the low-power standby circuit for an external circuit breaker of an electric energy meter is high in cost and has a large space occupied due to complex circuits.

[0006] In order to solve the above technical problems, the utility model adopts the following technical solutions:

[0007] The utility model provides a low-power standby circuit for an external circuit breaker of an electric energy meter, comprising:

[0008] Electromagnetic compatibility and rectification circuit, linear step-down power supply circuit, bus switch circuit, DC / DC power supply circuit, voltage-stabilized power supply circuit and MCU control circuit;

[0009] The electromagnetic compatibility and rectification circuit is communicatively connected to the linear step-down power supply circuit and the bus switch circuit respectively, and the bus switch circuit is also communicatively connected to the DC / DC power supply circuit and the MCU control circuit respectively. The linear step-down power supply circuit, the voltage-stabilized power supply circuit, and the MCU control circuit are communicatively connected in sequence, and the DC / DC power supply circuit is also communicatively connected to the voltage-stabilized power supply circuit.

[0010] Furthermore, the electromagnetic compatibility and rectification circuit includes a resistor RP1, a resistor RP2, a resistor RTA and a diode D1, one end of the resistor RP1 is connected to the live wire, the other end of the resistor RP1 is connected to one end of the resistor RP2 and one end of the resistor RTA respectively, the other end of the resistor RP2 is connected to the positive electrode of the diode D1, and the other end of the resistor RTA is connected to the neutral line and grounded.

[0011] Furthermore, the linear step-down power supply circuit includes a resistor R1, a resistor R2, a resistor R3, a capacitor C1 and a Zener diode D5, one end of the resistor R1 is connected to the cathode of the diode D1, the other end of the resistor R1 is connected to one end of the resistor R2, the other end of the resistor R2 is connected to one end of the resistor R3, the other end of the resistor R3 is respectively connected to one end of the capacitor C1 and the cathode of the Zener diode D5, and the other end of the capacitor C1 is connected to the anode of the Zener diode D5.

[0012] Furthermore, the bus switch circuit includes an optocoupler thyristor U2, a TVS tube D4 and a resistor R4, the 4th pin of the optocoupler thyristor U2 is respectively connected to the cathode of the diode D1, one end of the resistor R1, and one end of the TVS tube D4, the 6th pin of the optocoupler thyristor U2 is respectively connected to the other end of the TVS tube D4 and the DC / DC power supply circuit, the 1st pin of the optocoupler thyristor U2 is connected to one end of the resistor R4, and the other end of the resistor R4 is connected to the MCU control circuit.

[0013] Furthermore, the DC / DC power supply circuit includes a capacitor C2 and a DC / DC power supply module, one end of the capacitor C2 is connected to the 6th pin of the optocoupler thyristor U2 and the high voltage end of the DC / DC power supply module, and the other end of the capacitor C2 is connected to the ground end of the DC / DC power supply module.

[0014] Furthermore, the voltage-stabilized power supply circuit includes a diode D2, a diode D3, a capacitor C3, a capacitor C4 and a voltage-stabilizing chip U1, the positive electrode of the diode D2 is respectively connected to the negative electrode of the voltage-stabilizing diode D5 and the other end of the resistor R3, the negative electrode of the diode D2 is respectively connected to the negative electrode of the diode D3, one end of the capacitor C3, one end of the capacitor C4, and the input end of the voltage-stabilizing chip U1, the positive electrode of the diode D3 is connected to the DC / DC power supply module, the other end of the capacitor C3 is connected to the other end of the capacitor C4 and is grounded, and the output end of the voltage-stabilizing chip U1 is connected to the MCU control module.

[0015] Furthermore, the MCU control circuit includes a capacitor C5 and an MCU control module, one end of the capacitor C5 is connected to the output end of the voltage regulator chip U1 and the power supply end of the MCU control module respectively, and the other end of the capacitor C5 is connected to the ground end of the MCU control module.

[0016] Compared with the prior art, the low-power standby circuit of the electric energy meter external circuit breaker provided by the utility model has at least the following beneficial effects:

[0017] At present, the low-power standby circuit of the external circuit breaker of the electric energy meter on the market generally adopts MOS tube or triode, and is realized by closing the bus in a two-by-two combination. This method has the disadvantages of complex circuit, many components, large circuit board area, high cost, etc. The utility model has a simple structure and powerful functions. It uses a thyristor optocoupler as a bus switch, and does not need to use two high-voltage thyristors. The bus switch control response is fast, the control logic is simple, and it is not affected by electromagnetic interference. When the bus is opened, the continuous output capacity is 100mA, which meets the general load requirements of the external circuit breaker of the electric energy meter. When the bus is closed, the bus leakage current is only 10nA, and the current of the linear step-down power supply is 0.14mA. The utility model fully meets and exceeds the requirements of the State Grid and the China Southern Power Grid Company for the static leakage current of the external circuit breaker of the electric energy meter to be less than 0.2mA. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the scheme of the utility model, a brief introduction is given below to the figures required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 A structural block diagram of a low-power standby circuit of an external circuit breaker of an electric energy meter provided in an embodiment of the utility model;

[0020] Figure 2 A circuit diagram of a low-power standby circuit of an external circuit breaker of an electric energy meter provided in one embodiment of the utility model;

[0021] Figure 3 A circuit diagram of a low-power standby circuit of an external circuit breaker of an electric energy meter provided in another embodiment of the utility model. DETAILED DESCRIPTION

[0022] Unless otherwise defined, all technical and scientific terms used in this document have the same meaning as commonly understood by technicians in the technical field of the present invention; the terms used in this specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. For example, the directions or positions indicated by terms such as "length", "width", "up", "down", "left", "right", "front", "back", "vertical", "horizontal", "top", "bottom", "inside", and "outside" are based on the directions or positions shown in the drawings, which are only for the convenience of description and cannot be understood as limitations on the present technical solution.

[0023] The terms "including" and "having" and any variations thereof in the specification and claims of the utility model and the above-mentioned drawings are intended to cover non-exclusive inclusions; the terms "first", "second", etc. in the specification and claims of the utility model or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order. In the specification and claims of the utility model and the above-mentioned drawings, when an element is referred to as "fixed to" or "mounted on" or "disposed on" or "connected to" another element, it may be directly or indirectly located on the other element. For example, when an element is referred to as "connected to" another element, it may be directly or indirectly connected to the other element.

[0024] In addition, the reference to "embodiment" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiment may be included in at least one embodiment of the present invention. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0025] The utility model provides a low-power standby circuit for an external circuit breaker of an electric energy meter, comprising:

[0026] Electromagnetic compatibility and rectification circuit, linear step-down power supply circuit, bus switch circuit, DC / DC power supply circuit, voltage-stabilized power supply circuit and MCU control circuit; the electromagnetic compatibility and rectification circuit are communicatively connected with the linear step-down power supply circuit and the bus switch circuit respectively, the bus switch circuit is also communicatively connected with the DC / DC power supply circuit and the MCU control circuit respectively, the linear step-down power supply circuit, the voltage-stabilized power supply circuit and the MCU control circuit are communicatively connected in sequence, and the DC / DC power supply circuit is also communicatively connected with the voltage-stabilized power supply circuit.

[0027] The utility model has a simple structure and powerful functions, realizes the low-power standby of the external circuit breaker circuit of the electric energy meter, occupies a small space and has a low cost.

[0028] In order to enable those skilled in the art to better understand the method of the utility model, the technical solutions in the embodiments of the utility model will be clearly and completely described below in conjunction with the accompanying drawings.

[0029] The utility model provides a low-power standby circuit for an external circuit breaker of an electric energy meter. Figures 1 to 3 In this embodiment, the low-power standby circuit of the external circuit breaker of the electric energy meter includes:

[0030] Electromagnetic compatibility and rectification circuit, linear step-down power supply circuit, bus switch circuit, DC / DC power supply circuit, voltage-stabilized power supply circuit and MCU control circuit;

[0031] The electromagnetic compatibility and rectification circuit are communicatively connected to the linear step-down power supply circuit and the bus switch circuit respectively. The bus switch circuit is also communicatively connected to the DC / DC power supply circuit and the MCU control circuit respectively. The linear step-down power supply circuit, the voltage-stabilized power supply circuit, and the MCU control circuit are communicatively connected in sequence. The DC / DC power supply circuit is also communicatively connected to the voltage-stabilized power supply circuit.

[0032] Furthermore, in this embodiment, the electromagnetic compatibility and rectification circuit includes a power resistor RP1, a power resistor RP2, a varistor RTA and a diode D1, one end of the resistor RP1 is connected to the live wire, the other end of the resistor RP1 is connected to one end of the resistor RP2 and one end of the resistor RTA respectively, the other end of the resistor RP2 is connected to the positive electrode of the diode D1, and the other end of the resistor RTA is connected to the neutral line and grounded.

[0033] In another embodiment, the electromagnetic compatibility and rectification circuit includes a power resistor RP1, a power resistor RP2, a varistor RTA and a rectifier bridge D1, one end of the resistor RP1 is connected to the live wire, the other end of the resistor RP1 is connected to one end of the resistor RP2 and one end of the resistor RTA respectively, the other end of the resistor RP2 is connected to the fourth pin of the rectifier bridge D1, the other end of the resistor RTA is connected to the neutral line and the third pin of the rectifier bridge D1 respectively, the first pin of the rectifier bridge D1 is connected to one end of the resistor R1 and the fourth pin of the TVS tube D4 respectively, and the second pin of the rectifier bridge D1 is grounded.

[0034] Furthermore, in the present embodiment, the linear step-down power supply circuit includes a resistor R1, a resistor R2, a resistor R3, a capacitor C1 and a Zener diode D5, one end of the resistor R1 is connected to the cathode of the diode D1, the other end of the resistor R1 is connected to one end of the resistor R2, the other end of the resistor R2 is connected to one end of the resistor R3, the other end of the resistor R3 is respectively connected to one end of the capacitor C1 and the cathode of the Zener diode D5, and the other end of the capacitor C1 is connected to the anode of the Zener diode D5.

[0035] Furthermore, in this embodiment, the bus switch circuit includes an optocoupler thyristor U2, a TVS tube D4 and a resistor R4, the 4th pin of the optocoupler thyristor U2 is respectively connected to the cathode of the diode D1, one end of the resistor R1, and one end of the TVS tube D4, the 6th pin of the optocoupler thyristor U2 is respectively connected to the other end of the TVS tube D4 and the DC / DC power supply circuit, the 1st pin of the optocoupler thyristor U2 is connected to one end of the resistor R4, and the other end of the resistor R4 is connected to the MCU control circuit.

[0036] Furthermore, in this embodiment, the DC / DC power supply circuit includes a capacitor C2 and a DC / DC power supply module, one end of the capacitor C2 is connected to the 6th pin of the optocoupler thyristor U2 and the high voltage end of the DC / DC power supply module, and the other end of the capacitor C2 is connected to the ground end of the DC / DC power supply module.

[0037] Furthermore, in this embodiment, the voltage-stabilizing power supply circuit includes a diode D2, a diode D3, a capacitor C3, a capacitor C4 and a voltage-stabilizing chip U1. The positive electrode of the diode D2 is respectively connected to the negative electrode of the voltage-stabilizing diode D5 and the other end of the resistor R3, the negative electrode of the diode D2 is respectively connected to the negative electrode of the diode D3, one end of the capacitor C3, one end of the capacitor C4, and the input end of the voltage-stabilizing chip U1, the positive electrode of the diode D3 is connected to the DC / DC power supply module, the other end of the capacitor C3 is connected to the other end of the capacitor C4 and is grounded, and the output end of the voltage-stabilizing chip U1 is connected to the MCU control module.

[0038] Furthermore, in this embodiment, the voltage-stabilizing power supply circuit includes a diode D2, a diode D3, a capacitor C3, a capacitor C4 and a voltage-stabilizing chip U1. The positive electrode of the diode D2 is respectively connected to the negative electrode of the voltage-stabilizing diode D5 and the other end of the resistor R3, the negative electrode of the diode D2 is respectively connected to the negative electrode of the diode D3, one end of the capacitor C3, one end of the capacitor C4, and the input end of the voltage-stabilizing chip U1, the positive electrode of the diode D3 is connected to the DC / DC power supply module, the other end of the capacitor C3 is connected to the other end of the capacitor C4 and is grounded, and the output end of the voltage-stabilizing chip U1 is connected to the MCU control module.

[0039] In the low-power standby circuit of the external circuit breaker of the electric energy meter provided in this embodiment, after the AC power is input into the electromagnetic compatibility and rectification circuit, a part of it is supplied to the linear step-down power supply circuit, and a part of it is supplied to the bus switch circuit. The linear step-down power supply circuit supplies power to the voltage-stabilizing power supply circuit through the diode D2. The bus switch circuit is controlled by the MCU to realize the opening and closing of the DC / DC power supply circuit. The DC / DC power supply circuit supplies power to the voltage-stabilizing power supply circuit through the diode D3. The voltage-stabilizing power supply circuit supplies power to the MCU control circuit at the same time through the power from the linear step-down power supply circuit and the DC / DC power supply circuit respectively from the diode D2 and the diode D3. The MCU control circuit controls the bus switch circuit. When the motor needs to be driven, the bus is opened to realize the DC / DC power supply circuit to supply power to the motor. When the motor is finished working, the MCU controls the bus switch circuit to turn off the DC / DC power supply to realize low power consumption. When the DC / DC power supply is turned off, the MCU control circuit is powered by the linear step-down power supply circuit to realize the continuous operation of the MCU circuit.

[0040] The low-power standby circuit of the external circuit breaker of the energy meter described in the above embodiment is compared with the prior art. The low-power standby circuit of the external circuit breaker of the energy meter currently on the market generally adopts MOS tubes or triodes, and is realized by closing the bus in a two-by-two combination. This method has the disadvantages of complex circuit, many components, large circuit board area, high cost, etc. The utility model has a simple structure and powerful functions. It uses a thyristor optocoupler as a bus switch, and does not need to use two high-voltage thyristors. The bus switch control responds quickly, the control logic is simple, and it is not affected by electromagnetic interference. When the bus is opened, the continuous output capacity is 100mA, which meets the general load requirements of the external circuit breaker of the energy meter. When the bus is closed, the bus leakage current is only 10nA, and the current of the linear step-down power supply is 0.14mA. The utility model fully meets and exceeds the requirements of the State Grid and the China Southern Power Grid Company for the static leakage current of the external circuit breaker of the energy meter to be less than 0.2mA.

[0041] Obviously, the embodiments described above are only preferred embodiments of the utility model, rather than all embodiments. The preferred embodiments of the utility model are given in the accompanying drawings, but they do not limit the patent scope of the utility model. The utility model can be implemented in many different forms. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the utility model more thorough and comprehensive. Although the utility model is described in detail with reference to the aforementioned embodiments, for those skilled in the art, it is still possible to modify the technical solutions recorded in the aforementioned specific implementation methods, or to replace some of the technical features therein with equivalents. Any equivalent structure made using the contents of the utility model specification and the accompanying drawings, directly or indirectly used in other related technical fields, is also within the scope of patent protection of the utility model.

Claims

1. A low-power standby circuit for an external circuit breaker of an electric energy meter, characterized in that: include: Electromagnetic compatibility and rectification circuit, linear step-down power supply circuit, bus switch circuit, DC / DC power supply circuit, voltage-stabilized power supply circuit and MCU control circuit; The electromagnetic compatibility and rectification circuit is communicatively connected to the linear step-down power supply circuit and the bus switch circuit respectively, and the bus switch circuit is also communicatively connected to the DC / DC power supply circuit and the MCU control circuit respectively. The linear step-down power supply circuit, the voltage-stabilized power supply circuit, and the MCU control circuit are communicatively connected in sequence, and the DC / DC power supply circuit is also communicatively connected to the voltage-stabilized power supply circuit.

2. The low power consumption standby circuit of an external circuit breaker of an electric energy meter according to claim 1, characterized in that: The electromagnetic compatibility and rectification circuit includes a resistor RP1, a resistor RP2, a resistor RTA and a diode D1, one end of the resistor RP1 is connected to the live wire, the other end of the resistor RP1 is connected to one end of the resistor RP2 and one end of the resistor RTA respectively, the other end of the resistor RP2 is connected to the positive electrode of the diode D1, and the other end of the resistor RTA is connected to the neutral line and grounded.

3. The low power consumption standby circuit of an external circuit breaker of an electric energy meter according to claim 2, characterized in that: The linear step-down power supply circuit includes a resistor R1, a resistor R2, a resistor R3, a capacitor C1 and a Zener diode D5, one end of the resistor R1 is connected to the cathode of the diode D1, the other end of the resistor R1 is connected to one end of the resistor R2, the other end of the resistor R2 is connected to one end of the resistor R3, the other end of the resistor R3 is connected to one end of the capacitor C1 and the cathode of the Zener diode D5 respectively, and the other end of the capacitor C1 is connected to the anode of the Zener diode D5.

4. A low power consumption standby circuit for an external circuit breaker of an electric energy meter according to claim 3, characterized in that: The bus switch circuit includes an optocoupler thyristor U2, a TVS tube D4 and a resistor R4. The 4th pin of the optocoupler thyristor U2 is respectively connected to the cathode of the diode D1, one end of the resistor R1 and one end of the TVS tube D4. The 6th pin of the optocoupler thyristor U2 is respectively connected to the other end of the TVS tube D4 and a DC / DC power supply circuit. The 1st pin of the optocoupler thyristor U2 is connected to one end of the resistor R4, and the other end of the resistor R4 is connected to the MCU control circuit.

5. The low power consumption standby circuit of an external circuit breaker of an electric energy meter according to claim 4, characterized in that: The DC / DC power supply circuit includes a capacitor C2 and a DC / DC power supply module, one end of the capacitor C2 is connected to the 6th pin of the optocoupler thyristor U2 and the high voltage end of the DC / DC power supply module, and the other end of the capacitor C2 is connected to the ground end of the DC / DC power supply module.

6. A low-power standby circuit for an external circuit breaker of an electric energy meter according to claim 5, characterized in that: The voltage-stabilizing power supply circuit includes a diode D2, a diode D3, a capacitor C3, a capacitor C4 and a voltage-stabilizing chip U1. The anode of the diode D2 is connected to the cathode of the voltage-stabilizing diode D5 and the other end of the resistor R3, respectively. The cathode of the diode D2 is connected to the cathode of the diode D3, one end of the capacitor C3, one end of the capacitor C4 and the input end of the voltage-stabilizing chip U1, respectively. The anode of the diode D3 is connected to the DC / DC power supply module. The other end of the capacitor C3 is connected to the other end of the capacitor C4 and is grounded. The output end of the voltage-stabilizing chip U1 is connected to the MCU control circuit.

7. A low power consumption standby circuit for an external circuit breaker of an electric energy meter according to claim 6, characterized in that: The MCU control circuit includes a capacitor C5 and an MCU control module. One end of the capacitor C5 is connected to the output end of the voltage regulator chip U1 and the power supply end of the MCU control module respectively, and the other end of the capacitor C5 is connected to the ground end of the MCU control module.

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