A relay control circuit based on permission judgment and an electric energy meter

Abstract

The utility model relates to a kind of relay control circuit and electric energy meter based on permission judgment, the circuit includes electric energy meter MCU, permission judgment module and relay control module, the permission judgment module includes toggle switch, and the toggle switch switches to allow relay action signal and not allow relay action signal, the relay control module includes relay drive chip, when the toggle switch switches to allow relay action signal, the electric energy meter MCU can be realized relay drive control by sending pull-in brake control signal to relay drive chip.The permission lock makes electric energy meter in two states, avoids the security loophole or misoperation risk possibly existing in software control, improves the security and reliability of system.

Description

Technical Field

[0001] This utility model relates to the field of electricity meter technology, specifically to a relay control circuit and electricity meter based on access control. Background Technology

[0002] As a key device for metering and management in power systems, electricity meters, with their relays serving as the core control hub, bear the crucial mission of accurately executing remote on / off commands and achieving millisecond-level fault protection. Relays employ high-strength electrical isolation technology, effectively blocking high-voltage risks and ensuring operational safety. They also support multi-circuit intelligent control and real-time status feedback, flexibly adapting to diverse scenarios such as demand response and time-of-use metering, significantly improving electricity management efficiency. Currently, electricity meter products on the market have fully passed international authoritative certifications such as UL, CE, and IEC, possessing ultra-long mechanical life and excellent anti-interference capabilities, and can still operate stably in extreme environments, providing comprehensive and highly reliable operational protection for electricity meters. However, with the continuous expansion of the global electricity market, some overseas regions have put forward special requirements for the relay control of electricity meters, namely, that electricity meters must have two operating states: a relay-enabled state and a relay-disabled state.

[0003] Currently, most relay control schemes on the market are fixed-mode, unable to dynamically switch control permissions according to external needs. Existing technologies typically achieve relay control through software settings or fixed hardware configurations, lacking a flexible switching mechanism. When it is necessary to change the relay control permissions, reconfiguration or hardware replacement is often required, increasing costs. Furthermore, electricity meters often face complex operating conditions such as electromagnetic interference and power fluctuations in real-world applications. Existing control schemes lack effective anti-interference measures in the signal detection stage, which may lead to misjudgments or control failures, affecting the reliability and safety of the electricity meter. Utility Model Content

[0004] To address the aforementioned problems, this utility model provides a relay control circuit based on access control. The circuit includes an energy meter MCU, an access control module, and a relay control module. The access control module includes a toggle switch that switches between an allowed relay operation signal and an unallowed relay operation signal. The relay control module includes a relay driver chip. When the toggle switch is switched to the allowed relay operation signal, the energy meter MCU sends a trip control signal to the relay driver chip.

[0005] Preferably, the toggle switch includes pin 2, pin 3, and pin 4, pin 2 is connected to the disallow relay operation signal, pin 3 is grounded, and pin 4 is connected to the enable relay operation signal.

[0006] Based on the above scheme, the permission judgment module further includes a first resistor, a second resistor, a first capacitor, and a second capacitor. One end of the first resistor is connected to the power supply of the electricity meter system, and the other end is connected to the first capacitor and pin 2 of the toggle switch. The other end of the first capacitor is grounded. One end of the second resistor is connected to the power supply of the electricity meter system, and the other end is connected to the second capacitor and pin 4 of the toggle switch. The other end of the second capacitor is grounded.

[0007] Preferably, the first terminal of the relay driver chip is connected to the relay closing signal of the MCU terminal of the energy meter, the second terminal of the relay driver chip is connected to the relay opening signal of the MCU terminal of the energy meter, the third terminal of the relay driver chip outputs the relay control closing signal, and the fourth terminal of the relay driver chip outputs the relay control opening signal. When the relay closing signal of the MCU terminal of the energy meter is high, the relay driver chip controls the relay control closing signal to be high, and the relay closes.

[0008] Based on the above scheme, the relay control module further includes a third resistor, a fourth resistor, a fifth resistor, and a sixth resistor. The first terminal of the relay driver chip is grounded through the third resistor and connected to the relay tripping signal of the MCU terminal of the energy meter through the fourth resistor. The second terminal of the relay driver chip is connected to the relay closing signal of the MCU terminal of the energy meter through the fifth resistor and grounded through the sixth resistor.

[0009] Based on the above scheme, the relay control module further includes a relay control interface, an electrolytic capacitor, a third capacitor, and a fourth capacitor. The third and fourth terminals of the relay driver chip are connected to the relay control interface, and the fourth capacitor is connected between the third and fourth terminals. The fifth terminal of the relay driver chip is connected to the relay input power supply, the third capacitor, and the electrolytic capacitor, respectively.

[0010] On the other hand, this application also provides an electricity meter, including a relay control circuit based on permission judgment as described above.

[0011] Compared with the prior art, the beneficial effects of this utility model are as follows: 1. By toggling the switch, the physical level dynamic switching of relay action permissions is realized. Users or maintenance personnel can flexibly switch between the two states of "allowing relay action" and "disallowing relay action" by manually toggling the switch, which effectively meets the compliance requirements of different overseas regions for the control permissions of electricity meter relays. 2. Hardware-based access control avoids potential security vulnerabilities or erroneous operation risks associated with software control, thus improving system security and reliability. When the toggle switch is switched to the "relay operation not allowed" state, the electricity meter MCU can detect the corresponding low-level signal, thereby blocking remote or automatic circuit breaker commands, ensuring that the relay will not malfunction, and protecting the user's electricity rights and equipment safety. 3. Through circuit design, the stability and anti-interference ability of the signal are effectively enhanced, preventing false triggering caused by electromagnetic interference or power fluctuations, and ensuring that the relay can still work stably and reliably under complex operating conditions. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the control circuit structure of this utility model; Figure 2 This is a circuit diagram of the permission judgment module of this utility model; Figure 3 This is a schematic diagram of the toggle switch and its operation according to this utility model; Figure 4 This is the circuit diagram of the relay control module 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 utility model provides a relay control circuit based on access control, the circuit including an energy meter MCU, an access control module, and a relay control module. Among them, According to this embodiment, as Figure 2 As shown, the permission judgment module includes a toggle switch JY1, a first resistor RT1, a second resistor RT2, a first capacitor CT1, and a second capacitor CT2. JY1 includes pins 2, 3, and 4. Pin 2 of JY1 is connected to the relay-disallowed signal Relay_on_Test, pin 3 of JY1 is grounded, and pin 4 of JY1 is connected to the relay-allowed signal Relay_off_Test.

[0015] One end of RT1 is connected to the power supply DVDD of the electricity meter system, and the other end is connected to pin 2 of CT1 and JY1 respectively. The other end of CT1 is grounded to GND. One end of RT2 is connected to DVDD, and the other end is connected to pin 4 of CT2 and JY1 respectively. The other end of CT2 is connected to GND.

[0016] The working principle of the permission judgment module is as follows: Figure 3 As shown, pin 3 of the toggle switch is the common terminal and grounded. When the toggle switch is to pin 2, pin 2 is connected to pin 3, and the relay-disallowing signal Relay_on_Test connected to pin 2 is low. If the energy meter MCU detects that Relay_on_Test is low, it will not allow the relay to operate, and the energy meter cannot implement relay opening and closing behavior via communication commands. When the toggle switch is to pin 4, pin 4 is connected to pin 3, and the relay-allowing signal Relay_off_Test connected to pin 4 is low. If the energy meter MCU detects that Relay_off_Test is low, it will allow the relay to operate, and the energy meter can implement relay opening and closing behavior via communication commands.

[0017] RT1 and RT2 act as pull-up resistors to ensure that the Relay_on_Test and Relay_off_Test signal lines remain at a high level when the toggle switch is not turned on, preventing interference introduced by floating. CT1 and CT2 are connected between the signal lines and ground, forming an RC filter circuit to effectively filter out signal glitches caused by external electromagnetic interference or switch bounce, improving the accuracy and stability of MCU detection.

[0018] The relay control module includes a relay driver chip UW1. The first terminal of UW1 is connected to the relay closing signal M_Connector_Off_Control at the MCU of the energy meter. The second terminal of UW1 is connected to the relay opening signal M_Connector_On_Control at the MCU of the energy meter. The third terminal of UW1 outputs the relay closing control signal Connector_Off_In. The fourth terminal of UW1 outputs the relay opening control signal Connector_On_In.

[0019] According to this embodiment, as Figure 4As shown, the relay control module also includes a third resistor RW1, a fourth resistor RW2, a fifth resistor RW3, a sixth resistor RW4, a relay control interface JW1, an electrolytic capacitor EW1, a third capacitor CW1, and a fourth capacitor CW2. The first terminal of UW1 is grounded to GND via RW1 and connected to M_Connector_On_Control via RW2; the second terminal of UW1 is connected to M_Connector_Off_Control via RW3 and to GND via RW4; the third terminal of UW1 is connected to the first terminal of JW1, the fourth terminal of UW1 is connected to the second terminal of JW1, and CW2 is connected between the third and fourth terminals of UW1; the fifth terminal of UW1 is connected to the positive terminals of the relay input power supply RVCC, CW1, and EW1, respectively; the other terminal of CW1 is grounded to GND, and the negative terminal of EW1 is grounded.

[0020] The relay control module works as follows: When the relay closing signal M_Connector_Off_Control at the MCU end of the energy meter is high, and the relay opening signal M_Connector_On_Control at the MCU end of the energy meter is low, the relay driver chip controls the relay closing signal Connector_Off_In to be high and the relay opening signal Connector_On_In to be low. The relay closing signal Connector_Off_In is valid, and the relay is closed. When the relay opening signal M_Connector_On_Control at the MCU end of the energy meter is high, and the relay closing signal M_Connector_Off_Control at the MCU end of the energy meter is low, the relay driver chip controls the relay opening signal Connector_On_In to be high and the relay closing signal Connector_Off_In to be low. The relay opening signal Connector_On_In is valid, and the relay is open.

[0021] RW1 and RW4 act as pull-down resistors to ensure that the input terminals INA and INB of the driver chip UW1 remain low when the MCU is not outputting a signal, preventing false triggering. RW2 and RW3 are used for current limiting and isolation to protect the MCU output ports. EW1 and CW1 are connected in parallel between the power supply RVCC of UW1 and ground to achieve power supply decoupling, filter out high-frequency noise, and ensure stable power supply to the driver chip.

[0022] The overall working process of the relay control circuit based on access control of this utility model is as follows: First, the relay operation permission is set by toggling switch JY1. When relay operation needs to be disabled, JY1 is toggled to pin 2. At this time, pin 2 is connected to pin 3 (GND), causing the "Relay_on_Test" signal (not allowed to operate) to go low. The energy meter MCU monitors this signal status in real time. Once it detects that Relay_on_Test is low, it determines that the current operation mode is disabled, automatically blocking all opening and closing commands from the communication interface, ensuring that the relay cannot be triggered by remote or local commands, thus achieving safety locking.

[0023] When relay operation is required, switch JY1 to pin 4. At this point, pin 4 is connected to pin 3 (GND), causing the "Relay Off Test" signal to go low. Upon detecting this low-level signal, the MCU determines that the operation is enabled, opens the relay control channel, and prepares to receive opening and closing commands.

[0024] Provided permissions permit, the MCU of the electricity meter outputs control signals according to actual needs, and sends opening and closing control signals to the relay driver chip to achieve relay drive control. When a closing (relay closure) operation is required, the MCU sets the "relay closing signal" M_Connector_Off_Control to a high level, while the "relay opening signal" M_Connector_On_Control remains at a low level. This signal is sent to the driver chip UW1 via the input circuit composed of resistors RW2 and RW4. After UW1 responds, its output terminal Connector_Off_In outputs a high level, and Connector_On_In outputs a low level, driving the external relay to close and realizing circuit conduction.

[0025] When a tripping (relay disconnection) operation is required, the MCU sets the "relay tripping signal" M_Connector_On_Control to a high level, while the "relay closing signal" M_Connector_Off_Control remains low. Upon receiving this signal combination, UW1 reverses the output state, setting Connector_On_In to a high level and Connector_Off_In to a low level, thus driving the relay to disconnect and cutting off the circuit.

[0026] Throughout the control process, the access control module acts as a prerequisite security condition, ensuring that relay operations can only be performed under authorized conditions, thus constructing a hardware-level security protection mechanism. This novel circuit uses a hardware toggle switch to achieve access control switching, combined with filtering and protection circuits. This not only meets the compliance requirements of overseas markets but also significantly improves the system's security, anti-interference capabilities, and long-term operational reliability.

[0027] On the other hand, this application also provides an electricity meter that integrates the aforementioned relay control circuit. In practical applications, it can be deployed in the power distribution systems of residential, commercial, or industrial users, serving as an important sensing and control unit at the end of the smart grid. By integrating a hardware-level permission judgment mechanism, this electricity meter achieves mandatory control over relay operation permissions at the physical level, making it particularly suitable for special scenarios such as electricity disputes, equipment maintenance, transition periods for handling user arrears, or operation and maintenance debugging.

[0028] 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.

[0029] 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 relay control circuit based on access control, characterized in that, The circuit includes an energy meter MCU, an access control module, and a relay control module. The access control module includes a toggle switch, which switches between an enabled relay action signal and an disabled relay action signal. The relay control module includes a relay driver chip. When the toggle switch is switched to an enabled relay action signal, the energy meter MCU sends a trip control signal to the relay driver chip.

2. The relay control circuit based on permission judgment according to claim 1, characterized in that, The toggle switch includes pin 2, pin 3, and pin 4. Pin 2 is connected to the signal that the relay is not allowed to operate, pin 3 is grounded, and pin 4 is connected to the signal that the relay is allowed to operate.

3. A relay control circuit based on permission judgment according to claim 2, characterized in that, The permission determination module further includes a first resistor, a second resistor, a first capacitor, and a second capacitor. One end of the first resistor is connected to the power supply of the electricity meter system, and the other end is connected to the first capacitor and pin 2 of the toggle switch. The other end of the first capacitor is grounded. One end of the second resistor is connected to the power supply of the electricity meter system, and the other end is connected to the second capacitor and pin 4 of the toggle switch. The other end of the second capacitor is grounded.

4. A relay control circuit based on access control according to claim 1, characterized in that, The first terminal of the relay driver chip is connected to the relay closing signal of the MCU terminal of the energy meter, the second terminal of the relay driver chip is connected to the relay opening signal of the MCU terminal of the energy meter, the third terminal of the relay driver chip outputs the relay control closing signal, and the fourth terminal of the relay driver chip outputs the relay control opening signal. When the relay closing signal of the MCU terminal of the energy meter is high, the relay driver chip controls the relay control closing signal to be high, and the relay closes.

5. A relay control circuit based on permission judgment according to claim 4, characterized in that, The relay control module further includes a third resistor, a fourth resistor, a fifth resistor, and a sixth resistor. The first terminal of the relay driver chip is grounded through the third resistor and connected to the relay tripping signal of the MCU terminal of the energy meter through the fourth resistor. The second terminal of the relay driver chip is connected to the relay closing signal of the MCU terminal of the energy meter through the fifth resistor and grounded through the sixth resistor.

6. A relay control circuit based on permission judgment according to claim 4, characterized in that, The relay control module further includes a relay control interface, an electrolytic capacitor, a third capacitor, and a fourth capacitor. The third and fourth terminals of the relay driver chip are connected to the relay control interface, and the fourth capacitor is connected between the third and fourth terminals. The fifth terminal of the relay driver chip is connected to the relay input power supply, the third capacitor, and the electrolytic capacitor.

7. An electricity meter, characterized in that, Includes a relay control circuit based on permission determination as described in any one of claims 1-6.

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