Electric energy meter relay control circuit

Abstract

The utility model discloses an electric energy meter relay control circuit comprising a driving chip possessing a bidirectional control output end; two input control nodes; inputting into a filter network; the pull-down resistor is connected to the first input control node; the connector and the first voltage dividing network are connected between the third terminal and the ground and are used for detecting the voltage of the contact common end to form a detection signal; the second potential-divider network is connected between the fourth terminal and the ground and is used for detecting the voltage at the input end of the contact to form a second detection signal; the two-stage filter capacitor is connected to the detection signal ground in parallel; and the second two-stage filter capacitor is connected to the second detection signal ground in parallel. The utility model has the following beneficial effects: through an integrated bidirectional control structure and a dual-channel state monitoring mechanism, the control reliability of the relay is greatly improved, the comprehensive monitoring of the working state of the relay is realized, the power consumption of the system is reduced, and the service life of the relay is prolonged.

Description

Technical Field

[0001] The utility model relates to an electric energy meter relay control circuit. Background Art

[0002] Relays, as important actuators in electrical control systems, are widely used in the field of electric energy meters. Traditional relay control circuits usually use simple transistor or field-effect transistor drive methods. Although the above method has a simple structure, it has several technical problems:

[0003] First, traditional relay control circuits generally lack the ability to detect the relay's actual operating status. Control systems are unable to confirm whether the relay is operating as expected. This "blind operation" mode poses a significant safety hazard in critical applications. For example, in power control systems, if relay contacts stick or fail to operate, the control system cannot detect it in time, potentially leading to equipment damage or safety accidents.

[0004] Secondly, traditional relay drive circuits are usually composed of multiple discrete components, such as drive transistors, freewheeling diodes, current-limiting resistors, etc., which not only increase circuit complexity and failure points, but also reduce reliability and increase manufacturing and maintenance costs.

[0005] Third, conventional relay control circuits have insufficient anti-interference capabilities. Electromagnetic interference in industrial environments can easily cause relay malfunctions, especially when control signals are transmitted over long lines, where the interference problem is even more serious.

[0006] Fourth, traditional relay control circuits are difficult to simultaneously adapt to the control requirements of different types of relays, such as single-coil latching relays and double-coil latching relays, which limits the versatility and flexibility of the system.

[0007] Fifth, in applications involving high-voltage contact control, traditional circuits often lack effective high- and low-voltage isolation measures, posing safety risks.

[0008] Therefore, there is an urgent need to develop a relay control circuit with high integration, state monitoring function, strong anti-interference ability, safety, reliability and good versatility to solve the above technical problems. Utility Model Content

[0009] The utility model aims to provide an electric energy meter relay control circuit, which has the characteristics of integrated design, high reliability, high safety, low power consumption and easy maintenance.

[0010] The above technical objectives of the present invention are achieved through the following technical solutions:

[0011] An electric energy meter relay control circuit includes: a driver chip U35 having a bidirectional control output terminal; two input control nodes, wherein the first input control node is used to receive a relay pull-in instruction RLYON, and the second input control node is used to receive a relay disconnect instruction RLYOFF; an input filter network including a first series resistor R260 and a first parallel filter capacitor C208 connected to the first input control node, and a second series resistor R259 and a second parallel filter capacitor C207 connected to the second input control node; a pull-down resistor R258 connected to the first input control node; a connector J2 including a resistor for connecting a relay. The first output terminal Pin3 and the second output terminal Pin4 of the transformer coil, the third terminal Pin1 for connecting the contact common terminal, the fourth terminal Pin2 for connecting the contact input terminal, and the fifth terminal Pin5 for connecting the reference voltage; the first voltage divider network R262 / R263 is connected between the third terminal and ground, and is used to detect the voltage of the contact common terminal to form a first detection signal RLY_CHECK; the second voltage divider network is connected between the fourth terminal and ground, and is used to detect the voltage of the contact input terminal to form a second detection signal RELAY_IN; the dual-stage filter capacitors C209 / C210 are connected in parallel to the detection signal to ground.

[0012] The present invention is further configured as follows: the driving chip U35 is internally integrated with an H-bridge output structure, which can generate a forward or reverse voltage between the first output terminal and the second output terminal according to the signal state of the first input control node and the second input control node to drive a single-coil self-locking relay or a double-coil self-locking relay.

[0013] The utility model is further configured as follows: the first voltage divider network and the second voltage divider network both include a high-resistance resistor and a low-resistance resistor connected in series, and the resistance ratio of the high-resistance resistor to the low-resistance resistor is 100:1.

[0014] The utility model is further configured as follows: the high-resistance resistor is 100 kΩ, the low-resistance resistor is 1 kΩ, and the voltage division ratio enables the high-voltage signal to be safely reduced to a voltage level suitable for electronic detection.

[0015] The utility model is further configured as follows: the dual-stage filter capacitor includes a parallel combination of a small-capacitance capacitor and a large-capacitance capacitor, the small-capacitance capacitor is used to filter out high-frequency interference, and the large-capacitance capacitor is used to smooth low-frequency fluctuations.

[0016] The utility model is further configured as follows: the small-capacitance capacitor is 0.01 μF, and the large-capacitance capacitor is 0.1 μF, which together form a filtering structure for interference in different frequency ranges.

[0017] The utility model is further configured such that a creepage distance of not less than 3 mm is maintained between the high-voltage terminal and the low-voltage terminal in the connector (J2) to ensure electrical safety isolation.

[0018] The present invention is further configured such that the signals of the first input control node and the second input control node are mutually exclusive signals and will not be in a high level state at the same time.

[0019] In summary, the present invention has the following beneficial effects:

[0020] High-reliability control structure: A single WS4680Q chip is used to achieve bidirectional control of the relay, integrating an H-bridge output structure. This eliminates the need for external driver transistors and freewheeling diodes, significantly reducing the number of components and failure points, and improving system reliability.

[0021] Dual-channel status monitoring function: Two independent high-voltage voltage-dividing detection channels monitor the voltage on the relay input and output sides respectively, achieving comprehensive monitoring of the relay's actual working status, overcoming the shortcomings of "blind operation" in traditional relay control, and reducing the error rate of relay status judgment.

[0022] Multi-level anti-interference design: The input control signal adopts a three-component protection network of series resistor + parallel capacitor + pull-down resistor. The status detection adopts a two-stage filtering strategy with capacitors of different capacitance values ​​in parallel, forming a complete anti-interference barrier and reducing the system's false trigger rate in complex electrical environments.

[0023] Safety isolation structure: A 100kΩ / 1kΩ high-ratio voltage divider design safely converts high-voltage signals into low-voltage signals. The connector design maintains a creepage distance of at least 3mm between the high-voltage and low-voltage terminals, providing dual safety protection and reducing overall safety risks.

[0024] Extending relay life: The pulse control mode reduces the coil operating time, and the built-in freewheeling protection circuit reduces the sudden change of electromagnetic force when the coil is powered off. These protection measures increase the average service life of the relay.

[0025] Energy saving and low power consumption: Utilizing the characteristics of self-latching relays, only short pulses are required to switch states. The high-resistance voltage divider detection network reduces the static power consumption of the state monitoring circuit to the milliwatt level, thereby reducing the overall power consumption of the system.

[0026] Modular standard design: The 5-pin standard connector design and modular structure allow the relay control unit to be quickly replaced as a complete module, reducing the complexity and time of on-site repairs and significantly reducing maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of the circuit structure of the utility model. DETAILED DESCRIPTION

[0028] The following will be combined with the accompanying drawings of the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0029] like Figure 1 As shown, the utility model provides an electric energy meter relay control circuit, including a driver chip, two input control nodes, an input filter network, a pull-down resistor, a connector, a first voltage divider network, a second voltage divider network, and a two-stage filter capacitor.

[0030] The driver chip uses the WS4680Q chip (U35), which has a bidirectional control output terminal and an internal integrated H-bridge output structure. It can generate forward or reverse voltage between the output terminals according to the signal state of the input control node.

[0031] The two input control nodes include a first input control node for receiving the relay on command (RLYON) and a second input control node for receiving the relay off command (RLYOFF). The signals of these two control nodes are mutually exclusive and cannot be in a high-level state at the same time, ensuring clear control instructions and avoiding control conflicts.

[0032] The input filter network includes a first series resistor (R260, 1kΩ) and a first parallel filter capacitor (C208, 0.01μF) connected to the first input control node, and a second series resistor (R259, 1kΩ) and a second parallel filter capacitor (C207, 0.01μF) connected to the second input control node. This series resistor + parallel capacitor configuration forms an effective low-pass filter, current limiting and filtering the input signal, effectively suppressing spikes and noise on the control signal.

[0033] A pull-down resistor (R258, 5.1kΩ) is connected to the first input control node. The pull-down resistor ensures that the input is stable at a low level when there is no control signal, preventing false triggering caused by a floating state.

[0034] Connector (J2) is a 5-pin physical connector, including the first output terminal (Pin3) and the second output terminal (Pin4) for connecting to the relay coil, the third terminal (Pin1) for connecting to the contact common terminal, the fourth terminal (Pin2) for connecting to the contact input terminal, and the fifth terminal (Pin5) for connecting to the reference voltage. A creepage distance of at least 3mm is maintained between the connector's high-voltage terminals (Pin1, Pin2) and the low-voltage terminals (Pin3, Pin4) to ensure electrical safety isolation. The pin arrangement can be single-row linear or matrix, with a pin pitch of typically 2.54mm or 3.96mm.

[0035] The first voltage divider network (R262 / R263) is connected between the third terminal and ground, detecting the voltage at the contact common terminal to generate the first detection signal (RLY_CHECK). The second voltage divider network (not shown) is connected between the fourth terminal and ground to detect the voltage at the contact input terminal to generate the second detection signal (RELAY_IN). Both voltage divider networks consist of a high-resistance resistor (100kΩ) and a low-resistance resistor (1kΩ) connected in series with a resistance ratio of 100:1. This safely reduces the high-voltage signal (220V) to a low-voltage signal of approximately 2.2V, suitable for electronic testing.

[0036] The dual-stage filter capacitors (C209 / C210) are connected in parallel to the first detection signal ground. The small-capacitance capacitors are used to filter out high-frequency interference, and the large-capacitance capacitors are used to smooth low-frequency fluctuations, together forming a wide-band filter structure for interference in different frequency ranges.

[0037] The signal flow of this utility model is as follows: a first control signal enters from the input control node, passes through the input filter network, and is sent to the driver chip. The driver chip generates a corresponding output signal based on the input control signal, which drives the relay coil through the first and second output terminals of the connector. Simultaneously, the state of the relay contacts is fed back through the third and fourth terminals of the connector, passing through the first and second voltage divider networks to form a detection signal. This signal is then processed by the two-stage filter capacitor and sent to the control unit for monitoring the actual operating status of the relay.

[0038] When the present invention is applied to a single-coil latching relay, the two ends of the relay coil are connected to the first and second output terminals of the connector, respectively. When the driver chip receives the RLYON signal, a forward voltage (OA ≈ 0, OB ≈ VIN) is generated between OA and OB, energizing the coil and closing the relay. When the driver chip receives the RLYOFF signal, a reverse voltage (OA ≈ VIN, OB ≈ 0) is generated, reversely energizing the coil and releasing the relay.

[0039] When used in a dual-coil latching relay, the pull-in coil is connected to the first output terminal, and the release coil is connected to the second output terminal. When the driver chip receives the RLYON signal, OA outputs a low level, activating the pull-in coil; when it receives the RLYOFF signal, OB outputs a low level, activating the release coil.

[0040] This utility model determines the actual operating status and fault conditions of relay contacts by comparing the states of a first detection signal (RLY_CHECK) and a second detection signal 20 (RELAY_IN). When RELAY_IN is high and RLY_CHECK is low, the relay contacts are not closed; when both are high, the contacts are closed; and when RLY_CHECK is high and RLY_CHECK is low, the contacts are stuck. This dual-channel status monitoring mechanism significantly improves the system's reliability in relay status determination.

[0041] The driver chip also integrates a freewheeling protection circuit to absorb back EMF when the relay coil is de-energized, reducing mechanical shock. This protection mitigates the sudden change in electromagnetic force when the coil is de-energized, reducing the impact on the relay's mechanical components and significantly extending the relay's service life.

[0042] The circuit board of this utility model adopts a zoning design principle, clearly distinguishing the signal processing area, the driver output area, and the voltage detection area. The driver chip is located in the center, with other components distributed around it according to their functions. The input filter network is located near the chip input terminal, forming a compact signal conditioning area. The voltage divider network and the corresponding filter capacitor form an independent detection area. The high-voltage and low-voltage sections are clearly physically isolated, with an isolation distance of no less than 3mm. The connector is usually located at the edge of the circuit board to facilitate external connections, thereby improving signal integrity and system safety.

[0043] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. An electric energy meter relay control circuit, characterized in that: include: Driver chip U35, with bidirectional control output terminal; Two input control nodes, wherein the first input control node is used to receive the relay pull-in instruction RLYON, and the second input control node is used to receive the relay disconnection instruction RLYOFF; an input filter network comprising a first series resistor R260 and a first parallel filter capacitor C208 connected to the first input control node, and a second series resistor R259 and a second parallel filter capacitor C207 connected to the second input control node; a pull-down resistor R258 connected to the first input control node; Connector J2, including a first output terminal Pin3 and a second output terminal Pin4 for connecting to a relay coil, a third terminal Pin1 for connecting to a contact common terminal, a fourth terminal Pin2 for connecting to a contact input terminal, and a fifth terminal Pin5 for connecting to a reference voltage; A first voltage divider network R262 / R263 is connected between the third terminal and ground, and is used to detect the voltage of the contact common terminal to form a first detection signal RLY_CHECK; a second voltage divider network connected between the fourth terminal and ground, for detecting a voltage at the contact input terminal to form a second detection signal RELAY_IN; The dual-stage filter capacitors C209 / C210 are connected in parallel to the detection signal ground.

2. The electric energy meter relay control circuit according to claim 1, characterized in that: The driver chip U35 has an integrated H-bridge output structure, which can generate a forward or reverse voltage between the first output terminal and the second output terminal according to the signal state of the first input control node and the second input control node to drive a single-coil self-locking relay or a double-coil self-locking relay.

3. The electric energy meter relay control circuit according to claim 1, characterized in that: The first voltage divider network and the second voltage divider network both include a high-resistance resistor and a low-resistance resistor connected in series, and the resistance ratio of the high-resistance resistor to the low-resistance resistor is 100:

1.

4. The electric energy meter relay control circuit according to claim 3, characterized in that: The high-value resistor is 100kΩ and the low-value resistor is 1kΩ, allowing the high-voltage signal to be safely stepped down to a voltage level suitable for electronic detection.

5. The electric energy meter relay control circuit according to claim 1, characterized in that: The two-stage filter capacitor includes a parallel combination of small-value capacitors and large-value capacitors. The small-value capacitors are used to filter out high-frequency interference, and the large-value capacitors are used to smooth low-frequency fluctuations.

6. The electric energy meter relay control circuit according to claim 5, characterized in that: The small-value capacitor is 0.01μF, and the large-value capacitor is 0.1μF, which together form a filtering structure for interference in different frequency ranges.

7. The electric energy meter relay control circuit according to claim 1, characterized in that: A creepage distance of at least 3 mm is maintained between the high-voltage terminal and the low-voltage terminal in connector J2 to ensure electrical safety isolation.

8. The electric energy meter relay control circuit according to claim 1, characterized in that: The signals of the first input control node and the second input control node are mutually exclusive signals and will not be in a high level state at the same time.

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