Three-phase intelligent electric energy meter cover opening detection circuit and electric energy meter

Abstract

The three-phase intelligent electric energy meter cover opening detection circuit comprises a grading power supply circuit, a cover opening detection circuit and an MCU, the grading power supply circuit comprises a first diode, a second diode, a third diode, a fourth diode, a first voltage stabilizing chip and a second voltage stabilizing chip, the anode of the first diode is connected with 6V input, and the cathode of the first diode is connected with an input pin of the second voltage stabilizing chip; an output pin of the second voltage-stabilizing chip is connected with a VBB input end of the uncovering detection circuit and a VCC pin of the MCU, an anode of the second diode is connected with 12V input, a cathode of the second diode is connected with input pins of the two voltage-stabilizing chips, an output pin of the first voltage-stabilizing chip is connected with an anode of the third diode, an anode of the fourth diode is connected with 3.6 V input, and an output pin of the third diode is connected with an anode of the fourth diode. The cathode of the third diode and the cathode of the fourth diode are combined and then are respectively connected with the VRTC input end of the cover opening detection circuit and the VRTC pin of the MCU. Therefore, under the condition that the 3.6 V clock battery supplies power, the cover opening event recording function can be achieved.

Description

Technical Field

[0001] This utility model relates to the field of smart energy meter technology, and in particular to a three-phase smart energy meter cover opening detection circuit and energy meter. Background Technology

[0002] Cover opening event logging is an important data point in three-phase smart meters, monitoring whether cover opening events occur during grid connection. Three-phase smart meters have three external voltage inputs: mains power, a 6V meter reading battery, and a 3.6V clock battery. The 3.6V clock battery typically powers only the internal real-time clock (RTC) of the MCU. Currently, most three-phase meters can log cover opening events when connected to 220V mains power or a 6V meter reading battery. When the meter is powered off and the meter reading battery is low on voltage, cover opening event logging will not occur. Utility Model Content

[0003] In view of the above-mentioned shortcomings of the prior art, the purpose of this utility model is to provide a three-phase smart energy meter cover opening detection circuit and energy meter, which can also realize the cover opening event recording function when powered by a 3.6V clock battery.

[0004] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0005] A three-phase smart energy meter cover opening detection circuit includes a graded power supply circuit, a cover opening detection circuit, and an MCU. The cover opening detection circuit includes a VBB input terminal, a VRTC input terminal, and a push-button switch with four interfaces. The four interfaces form two sets of switch contacts. Two interfaces in the first set of switch contacts are connected to the VBB input terminal and the VRTC input terminal, respectively. Two interfaces in the second set of switch contacts are connected to the VRTC input terminal and the cover opening detection pin of the MCU, respectively. The push-button switch allows selection to simultaneously turn on or off both sets of switch contacts. The graded power supply circuit includes a first diode, a second diode, a third diode, a fourth diode, a first voltage regulator chip, and a second voltage regulator chip. The anode of the first diode is connected to a 6V input. The cathode is connected to the input pin of the second voltage regulator chip, and the output pin of the second voltage regulator chip forms the VBB output terminal. The VBB output terminal is connected to the VBB input terminal of the cover opening detection circuit and the VCC pin of the MCU, respectively. The anode of the second diode is connected to the 12V input, and the cathode of the second diode is connected to the input pins of the first voltage regulator chip and the input pins of the second voltage regulator chip. The output pin of the first voltage regulator chip is connected to the anode of the third diode, and the anode of the fourth diode is connected to the 3.6V input. The cathodes of the third and fourth diodes are combined to form the VRTC output terminal, which is connected to the VRTC input terminal of the cover opening detection circuit and the VRTC pin of the MCU, respectively. The 12V input is obtained by stepping down the AC mains power through a transformer.

[0006] Optionally, the graded power supply circuit further includes a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor, a sixth capacitor, and a seventh capacitor. The cathodes of the first diode and the second diode are grounded through the first capacitor. The input pin of the first voltage regulator chip is grounded through the second capacitor. The output pin of the first voltage regulator chip is grounded through the third capacitor. The input pin of the second voltage regulator chip is grounded through the fourth capacitor. The output pin of the second voltage regulator chip is grounded through the fifth, sixth, and seventh capacitors connected in parallel.

[0007] Optionally, the second diode consists of two diodes connected in parallel in the same direction.

[0008] Optionally, the third diode is composed of two diodes connected in parallel in the same direction, and then a third diode connected in series in the same direction.

[0009] Optionally, the cover opening detection circuit further includes a first resistor, a second resistor, a third resistor, an eighth capacitor, and a ninth capacitor. The first resistor is connected in series between one interface of the second set of switch contacts and the VRTC input terminal. The second resistor is connected in series between the other interface of the second set of switch contacts and the cover opening detection pin of the MCU. The interface of the first set of switch contacts connected to the VBB input terminal is grounded through the eighth capacitor. One end of the second resistor connected to the other interface of the second set of switch contacts is grounded through the third resistor. One end of the second resistor connected to the cover opening detection pin of the MCU is grounded through the ninth capacitor.

[0010] Optionally, it also includes a fourth resistor, a tenth capacitor, an eleventh capacitor, and a twelfth capacitor. The fourth resistor is connected in series between the VRTC output terminal and the VRTC pin of the MCU. One end of the fourth resistor connected to the VRTC output terminal is grounded through the tenth capacitor. The VCC pin of the MCU is grounded through the eleventh and twelfth capacitors connected in parallel.

[0011] Another technical solution adopted by this utility model is:

[0012] An electricity meter includes the aforementioned three-phase smart electricity meter cover opening detection circuit.

[0013] The beneficial effects of this utility model are as follows:

[0014] This invention aims to solve the problem of three-phase smart meters failing to record cover opening events when powered by a 3.6V clock battery. A hierarchical power supply circuit is employed, prioritizing the power supply to the 220V AC mains power, the 6V meter reading battery, and the 3.6V clock battery. The 220V AC mains power has the highest priority and powers the meter first, while the 3.6V clock battery has the lowest priority. When the meter is connected to AC mains or a 6V meter reading battery is present, the MCU is powered by either AC mains or the 6V meter reading battery. When either power input is disconnected, the 3.6V clock battery provides power. Furthermore, the 3.6V clock battery is modified to simultaneously power both the MCU and the RTC clock, thus enabling cover opening event recording even when powered by the 3.6V clock battery. Attached Figure Description

[0015] Figure 1 The diagram shown is a schematic diagram of the graded power supply circuit of the three-phase smart energy meter cover opening detection circuit according to an embodiment of this utility model.

[0016] Figure 2 The diagram shown is a schematic diagram of the cover opening detection circuit of the three-phase smart energy meter according to an embodiment of this utility model.

[0017] Figure 3 The diagram shown is a schematic of the MCU and its peripheral circuits of the three-phase smart energy meter cover opening detection circuit according to an embodiment of this utility model. Detailed Implementation

[0018] To better understand the technical content, objectives, and effects of this utility model, the following detailed description, in conjunction with specific embodiments and accompanying drawings, is provided. It should be noted that, unless otherwise specified, the embodiments and features of this utility model can be combined with each other. Many specific details are set forth in the following description to provide a thorough understanding of this utility model; the described embodiments are merely a part of, and not all, of the embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without inventive effort are within the scope of protection of this utility model.

[0019] Please refer to Figure 1-3 As shown, Embodiment 1 of this utility model is as follows:

[0020] A three-phase smart energy meter cover opening detection circuit includes a graded power supply circuit, a cover opening detection circuit, an MCU, a resistor R4, a capacitor C10, a capacitor C11, and a capacitor C12. Figure 1 As shown, the graded power supply circuit includes a 12V input terminal, a 6V input terminal, a 3.6V input terminal, diodes D1 to D7, capacitors C1 to C7, a 4.4V voltage regulator chip U1, and a 3.3V voltage regulator chip U2. In a specific example, the voltage regulator chip U1 is model MD8244, and the voltage regulator chip U2 is model MD8233. The anode of diode D1 is connected to the 6V input through the 6V input terminal, and the cathode of diode D1 is connected to the input pin IN of the voltage regulator chip U2. The anodes of diodes D2 and D3, connected in parallel in the same direction, are connected to a 12V input via a 12V input terminal. This 12V input is obtained from the AC mains voltage through a transformer. The cathodes of diodes D2 and D3 are connected to the input pins IN of voltage regulator chips U1 and U2, respectively. The output pin OUT of voltage regulator chip U1 is connected to the anodes of diodes D4 and D5, also connected in parallel in the same direction. The cathodes of diodes D4 and D5 are connected to the anode of diode D6. The anode of diode D7 is connected to a 3.6V input via a 3.6V input terminal. The cathodes of diodes D1, D2, and D3 are grounded via capacitor C1. The input pin IN of voltage regulator chip U1 is grounded via capacitor C2, and the output pin OUT of voltage regulator chip U1 is grounded via capacitor C3. The input pin IN of voltage regulator chip U2 is grounded via capacitor C4, and the output pin OUT of voltage regulator chip U2 is grounded via parallel capacitors C5, C6, and C7. The ground pins GND of voltage regulator chip U1 and U2 are both grounded. The output pin OUT of voltage regulator chip U2 forms the VBB output terminal, and the cathodes of diode D6 and D7 are combined to form the VRTC output terminal.

[0021] like Figure 2 As shown, the cover-opening detection circuit includes a VBB input terminal, a VRTC input terminal, four key switches (1, 2, 3, 4), resistors R1 to R3, and capacitors C8 and C9. The four interfaces form two sets of switch contacts. In the first set, interface 3 is connected to the VRTC input terminal, and interface 4 is connected to both the VBB input terminal and one end of capacitor C8. In the second set, interface 1 is connected to the VRTC input terminal via resistor R1, and interface 2 is connected to both resistor R2 and resistor R3. The other end of resistor R2 is connected to the MCU's cover-opening detection pin (Key_CoverUp) and one end of capacitor C9. The other ends of capacitor C8, resistor R3, and capacitor C9 are all grounded. The key switch selects whether both sets of switches are simultaneously on or off. Specifically, when the key is on, interfaces 1 and 2 are on, and interfaces 3 and 4 are on; when the key is off, interfaces 1 and 2 are off, and interfaces 3 and 4 are off. The VBB output terminal is connected to the VBB input terminal of the lid opening detection circuit, and the VRTC output terminal is connected to the VRTC input terminal of the lid opening detection circuit.

[0022] like Figure 3 The diagram shows the MCU and its peripheral circuitry. Resistor R4 is connected in series between the VRTC output and the MCU's VRTC pin. One end of resistor R4 connected to the VRTC output is grounded via capacitor C10. The MCU's VCC pin is connected to the VBB output, and the MCU's VCC pin is also grounded via parallel capacitors C11 and C12. In a specific example, the MCU model is HT6035.

[0023] Embodiment two of this utility model is as follows:

[0024] An electricity meter includes the three-phase smart electricity meter cover opening detection circuit described in Embodiment 1.

[0025] The working principle of this utility model is as follows:

[0026] When the electricity meter is connected to the 220V mains power, the voltage is stepped down by the transformer to output the 12V input in the above circuit.

[0027] When a 12V input is present, diode D1 is cut off, while diodes D2 and D3 are conducting. At this time, the 6V meter battery does not supply power to the circuit. The 12V is input to voltage regulator chips U1 and U2 respectively. After passing through voltage regulator chip U1, the 12V output is 4.4V. At this time, diodes D4, D5, and D6 are conducting, while diode D7 is cut off. The 3.6V clock battery does not supply power to the circuit; instead, the 4.4V is output to the VRTC output terminal. After passing through voltage regulator chip U2, the 12V output is 3.3V to the VBB output terminal.

[0028] When the electricity meter is disconnected from the mains power, there is no 12V input in the circuit. Diode D1 conducts, while diodes D2 and D3 are cut off. At this time, 6V is input to voltage regulator chips U1 and U2 respectively. After passing through voltage regulator chip U1, the 12V output is 4.4V. At this time, diodes D4, D5, and D6 conduct, while diode D7 is cut off. The 3.6V clock battery does not supply power to the circuit; instead, the 4.4V is output to the VRTC output terminal. After passing through voltage regulator chip U2, the 6V output is 3.3V output to the VBB output terminal.

[0029] When the electricity meter is disconnected from the mains power and the 6V meter reading battery is low on voltage, diodes D1-D6 are all cut off, and the circuit is powered only by the 3.6V clock battery. The 3.6V is output to the VRTC output terminal via diode D7. When the switch button KEY is pressed, interfaces 1 and 2 are connected, and interfaces 3 and 4 are connected. The VRTC is directly connected to VBB, and the 3.6V clock battery powers both the MCU and RTC. When the switch button KEY is released, the 3.6V clock battery powers only the RTC.

[0030] In summary, the three-phase smart energy meter cover-opening detection circuit and energy meter of this invention can record cover-opening events under different power supply conditions. The power supply priority is given to mains power, followed by the 6V meter reading battery, and finally the 3.6V clock battery. When the energy meter is in the 3.6V clock battery power supply mode, if the meter cover is closed (no cover opening occurs), the clock battery only powers the RTC module in the MCU. When the meter cover is opened (cover opening occurs), the clock battery powers both the MCU and the RTC module simultaneously, recording the cover opening event. Therefore, even when the mains power is disconnected or the meter reading battery is low on voltage, the cover opening event can still be recorded while minimizing clock battery power consumption and extending its lifespan.

[0031] The above description is merely an embodiment of the present utility model and does not limit the patent scope of the present utility model. Therefore, any modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present utility model without departing from the technical solution of the present utility model shall still fall within the scope of the technical solution of the present utility model.

Claims

1. A three-phase smart energy meter cover opening detection circuit, characterized in that, The system includes a tiered power supply circuit, a lid opening detection circuit, and an MCU. The lid opening detection circuit includes a VBB input terminal, a VRTC input terminal, and a four-interface push-button switch. These four interfaces form two sets of switch contacts. Two interfaces in the first set are connected to the VBB input terminal and the VRTC input terminal, respectively. Two interfaces in the second set are connected to the VRTC input terminal and the lid opening detection pin of the MCU, respectively. A push-button switch allows simultaneous activation or deactivation of both sets of switches. The tiered power supply circuit includes a first diode, a second diode, a third diode, a fourth diode, a first voltage regulator chip, and a second voltage regulator chip. The anode of the first diode is connected to the 6V input, and the cathode of the first diode is connected to the second voltage regulator chip. The input pins of the chip and the output pins of the second voltage regulator chip form the VBB output terminal. The VBB output terminal is connected to the VBB input terminal of the cover opening detection circuit and the VCC pin of the MCU, respectively. The anode of the second diode is connected to the 12V input, and the cathode of the second diode is connected to the input pins of the first and second voltage regulator chips. The output pin of the first voltage regulator chip is connected to the anode of the third diode, and the anode of the fourth diode is connected to the 3.6V input. The cathodes of the third and fourth diodes are combined to form the VRTC output terminal. The VRTC output terminal is connected to the VRTC input terminal of the cover opening detection circuit and the VRTC pin of the MCU, respectively. The 12V input is obtained by stepping down the AC mains power through a transformer.

2. The three-phase smart energy meter cover opening detection circuit according to claim 1, characterized in that, The graded power supply circuit further includes a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor, a sixth capacitor, and a seventh capacitor. The cathodes of the first diode and the second diode are grounded through the first capacitor. The input pin of the first voltage regulator chip is grounded through the second capacitor. The output pin of the first voltage regulator chip is grounded through the third capacitor. The input pin of the second voltage regulator chip is grounded through the fourth capacitor. The output pin of the second voltage regulator chip is grounded through the fifth, sixth, and seventh capacitors connected in parallel.

3. The three-phase smart energy meter cover opening detection circuit according to claim 1, characterized in that, The second diode consists of two diodes connected in parallel in the same direction.

4. The three-phase smart energy meter cover opening detection circuit according to claim 1, characterized in that, The third diode consists of two diodes connected in parallel in the same direction, and then another diode connected in series in the same direction.

5. The three-phase smart energy meter cover opening detection circuit according to claim 1, characterized in that, The lid opening detection circuit further includes a first resistor, a second resistor, a third resistor, an eighth capacitor, and a ninth capacitor. The first resistor is connected in series between one interface of the second set of switch contacts and the VRTC input terminal. The second resistor is connected in series between the other interface of the second set of switch contacts and the lid opening detection pin of the MCU. The interface of the first set of switch contacts connected to the VBB input terminal is grounded through the eighth capacitor. One end of the second resistor connected to the other interface of the second set of switch contacts is grounded through the third resistor. One end of the second resistor connected to the lid opening detection pin of the MCU is grounded through the ninth capacitor.

6. The three-phase smart energy meter cover opening detection circuit according to claim 1, characterized in that, It also includes a fourth resistor, a tenth capacitor, an eleventh capacitor, and a twelfth capacitor. The fourth resistor is connected in series between the VRTC output terminal and the VRTC pin of the MCU. One end of the fourth resistor connected to the VRTC output terminal is grounded through the tenth capacitor. The VCC pin of the MCU is grounded through the eleventh and twelfth capacitors connected in parallel.

7. An electricity meter, characterized in that, The three-phase smart energy meter cover opening detection circuit includes any one of claims 1-6.

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