Control method and control circuit of magnetic latching relay

Abstract

The invention relates to the technical field of electrical control, and provides a control method and a control circuit of a magnetic latching relay. The method comprises the steps that a polarity switching unit is controlled to provide direction-variable driving current for a coil of the magnetic latching relay, and the polarity switching unit is of a double-H-bridge topological structure formed by cross connection of two single-pole double-throw relays; pulse signals which are conducted alternately are generated and output, and on-off of corresponding contacts in the polarity switching unit is controlled through an optocoupler isolation driving module, so that driving current pulses with variable directions are generated; by sampling the voltage of the contact of the magnetic latching relay, the on-off state of the magnetic latching relay is monitored in real time. According to the technical scheme, low-power-consumption and high-reliability control of the magnetic latching relay is achieved through the double-relay H bridge and state feedback.

Description

Technical Field

[0001] This application relates to the field of electrical control technology, and in particular to a control method and control circuit for a magnetic latching relay. Background Technology

[0002] A magnetic latching relay is a bistable relay that uses pulsed current to drive and achieves contact self-holding through an internal permanent magnet. Only a brief control pulse needs to be applied during operation or reset. Its coil does not consume electrical energy in steady state, thus exhibiting a significant advantage of extremely low power consumption. It is particularly suitable for applications with stringent energy-saving requirements, such as charging and discharging control units in electric vehicles, smart meters, and uninterruptible power supply systems.

[0003] Currently, the core of driving a magnetic latching relay lies in controlling the direction of the current flowing through its coil, thereby utilizing the interaction between electromagnetic force and permanent magnet force to drive the contacts to close or release. In existing technology, the most typical driving scheme uses an H-bridge circuit. By controlling the on and off states of the diagonal switches in the H-bridge, the polarity of the voltage applied across the coil can be easily changed, thus generating a forward or reverse driving current.

[0004] However, the aforementioned H-bridge drive scheme has some inherent drawbacks. First, semiconductor switches have on-resistance when turned on and switching losses during switching, especially when driving the large current required for high-power magnetic latching relays, where their power consumption and heat generation are significant, requiring additional heat dissipation design and increasing system complexity and cost. Second, semiconductor devices are sensitive to overvoltage, overcurrent, and external electromagnetic interference. In complex industrial electromagnetic environments (e.g., near the motor drive system of electric vehicles), their reliability is challenged, and there is a risk of false triggering or damage. Furthermore, although dedicated driver chips have high integration, they are often expensive and lack flexibility, making it difficult to adapt to all specifications of magnetic latching relays. Summary of the Invention

[0005] This application provides a control method and control circuit for a magnetic latching relay, which achieves low power consumption and high reliability control of the magnetic latching relay through a dual-relay H-bridge and state feedback.

[0006] On one hand, this application provides a control method for a magnetic latching relay, the method comprising: By controlling the polarity switching unit, a variable-direction drive current is provided to the coil of the magnetic latching relay. The polarity switching unit is composed of two single-pole double-throw relays cross-connected to form a double H-bridge topology. The alternating conduction pulse signal is generated and output, and the on / off state of the corresponding contact in the polarity switching unit is controlled by the optocoupler isolation drive module to generate the variable-direction drive current pulse. The on / off state of the magnetic latching relay is monitored in real time by sampling the voltage at the contacts of the magnetic latching relay.

[0007] On the other hand, this application provides a magnetic latching relay control circuit for implementing the above control method, comprising: The polarity switching unit consists of two single-pole double-throw relays, whose contacts are cross-connected to form a double H-bridge topology. The two output terminals of the double H-bridge topology are used to connect to the coils of the magnetic latching relays. The drive control unit has its output connected to the coils of two single-pole double-throw relays in the polarity switching unit. It is used to receive control signals from an external controller and generate the alternating conduction pulse signals to drive the polarity switching unit to operate. The status feedback unit has a sampling terminal for connecting to the contacts of the magnetic latching relay, and its output terminal provides a feedback signal characterizing the on / off state of the contacts.

[0008] As can be seen from the technical solution provided in this application, on the one hand, this application uses a double H-bridge topology structure composed of two single-pole double-throw relays cross-connected as the polarity switching unit, replacing the traditional semiconductor H-bridge. Since the relay contacts are mechanical contacts, their contact resistance when conducting is much lower than the conduction resistance of semiconductor devices. Therefore, the conduction loss in the current path of this solution is extremely low. The polarity switching unit only needs to consume a small amount of electrical energy to drive its coil at the moment of switching. Under steady state, neither the magnetic latching relay itself nor the polarity switching unit consumes any electrical energy, thereby achieving extremely low standby power consumption at the system level. At the same time, mechanical contacts are not easily affected by external electromagnetic interference. Their on / off state is determined by the mechanical structure, which has strong anti-interference ability and can effectively avoid malfunctions caused by interference in semiconductor solutions, significantly improving the reliability of the entire control path. On the other hand, this application adopts ordinary, standard The core drive circuit is constructed using a single-pole double-throw relay, eliminating the need for expensive power semiconductor switching transistors or dedicated drive chips. Ordinary relays, as mature and widely used basic components, offer significant cost advantages and have simple drive requirements, simplifying circuit design and reducing performance requirements for the core control components, thus contributing to overall cost control. Thirdly, this application monitors the on / off state of the magnetic latching relay contacts in real time by sampling the voltage, enabling direct feedback of the control results. This ensures the system is no longer operating blindly but can confirm whether the command has been correctly executed. This status feedback allows for timely identification of control anomalies caused by contact sticking, drive failure, etc., providing crucial information for further safety measures. This upgrades simple switching control to intelligent operation with preliminary fault diagnosis capabilities, enhancing the safety and maintainability of the entire controlled system. In summary, the technical solution of this application achieves low-power, high-reliability control of magnetic latching relays through a dual-relay H-bridge and status feedback. Attached Figure Description

[0009] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0010] Figure 1 This is a flowchart of the control method for a magnetic latching relay provided in the embodiments of this application; Figure 2 This is a schematic diagram of the overall system architecture of the magnetic latching relay control circuit provided in the embodiments of this application; Figure 3 This is a timing flowchart of the control method for a magnetic latching relay provided in an embodiment of this application; Figure 4 This is a schematic diagram of the magnetic latching relay control circuit provided in the embodiments of this application. Detailed Implementation

[0011] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0012] In this specification, adjectives such as "first" and "second" are used only to distinguish one element or action from another, without necessarily requiring or implying any actual such relationship or order. Where circumstances permit, reference to an element or component or step (etc.) should not be construed as being limited to only one of the elements, components, or steps, but may be one or more of the elements, components, or steps, etc.

[0013] For ease of description, the dimensions of the various parts shown in the accompanying drawings are not drawn to actual scale.

[0014] Currently, the core of driving magnetic latching relays lies in controlling the direction of the current flowing through its coil, thereby utilizing the interaction between electromagnetic force and permanent magnet force to drive the contacts to close or release. In existing technology, the most typical driving scheme uses an H-bridge circuit. By controlling the on and off states of the diagonal switches in the H-bridge, the polarity of the voltage applied across the coil can be easily changed, thus generating a forward or reverse driving current. However, the aforementioned H-bridge driving scheme has some inherent drawbacks. First, semiconductor switches have on-resistance when on and switching losses during switching, especially when driving high-power magnetic latching relays with large currents, their power consumption and heat generation are significant, requiring additional heat dissipation design, increasing system complexity and cost. Second, semiconductor devices are sensitive to overvoltage, overcurrent, and external electromagnetic interference. In complex industrial electromagnetic environments (e.g., near the motor drive system of electric vehicles), their reliability faces challenges, potentially leading to false triggering or damage. Furthermore, while dedicated driver chips have high integration, they are often expensive and lack flexibility, making it difficult to adapt to all specifications of magnetic latching relays.

[0015] To address the aforementioned problems in the prior art, this application proposes a control method for a magnetic latching relay, the flowchart of which is attached. Figure 1 As shown, the main steps include S101 to S103, which are detailed below: Step S101: By controlling the polarity switching unit, a variable-direction drive current is provided to the coil of the magnetic latching relay. The polarity switching unit is composed of two single-pole double-throw relays cross-connected to form a double H-bridge topology.

[0016] If an H-bridge is constructed using several switching transistors (e.g., MOSFETs or IGBTs) as in existing technologies, significant conduction losses and heat generation will occur under high-current applications due to the inherent on-resistance of power semiconductor devices when they are turned on. This requires additional heat dissipation design, increasing system complexity and size. Simultaneously, semiconductor devices are highly sensitive to electrostatic discharge, surge voltage, and electromagnetic interference from surrounding motors, posing reliability challenges in harsh industrial environments. Even with integrated H-bridge driver chips, while highly integrated, they are typically expensive, and their output current capability, withstand voltage rating, and other parameters are fixed, lacking flexibility and making it difficult to optimally adapt to all specifications of magnetic latching relays. To address the problems of high conduction losses, susceptibility to electromagnetic interference, and high cost associated with existing technologies such as H-bridge circuits based on semiconductor switching transistors when driving magnetic latching relays, the technical solution of this application provides a variable-direction drive current to the coil of the magnetic latching relay by controlling a polarity switching unit. This polarity switching unit consists of two single-pole double-throw relays cross-connected to form a dual H-bridge topology. As can be seen from the technical solution adopted in this application, on the one hand, using the metal contacts of a mechanical relay for current switching results in a much lower on-resistance than semiconductor devices, extremely low path loss, and the physical on / off state of the mechanical contacts is unaffected by electromagnetic interference, fundamentally improving anti-interference capability and system reliability; on the other hand, using two standardized single-pole double-throw relays, which are common and low-cost components, and through a clever double H-bridge topology connection, achieves the same polarity switching function as dedicated chips, offering significant cost advantages and broad specification compatibility. Figure 2 The diagram shown is a schematic diagram of the overall system architecture of the magnetic latching relay control circuit provided in the embodiment of this application. The polarity switching unit is composed of two single-pole double-throw relays cross-connected to form a double H-bridge topology.

[0017] Step S102: Generate and output alternating conduction pulse signals, and control the on / off state of the corresponding contacts in the polarity switching unit through the optocoupler isolation drive module to generate drive current pulses with variable direction.

[0018] If the relay coil is directly driven by the microcontroller's I / O port, the driving capability of the microcontroller's I / O port is usually insufficient to directly drive the relay coil. Furthermore, directly introducing the high-voltage back electromotive force induced by the relay coil into the microcontroller port can easily damage the microcontroller, making the system extremely fragile. If a non-isolated semiconductor amplification driving scheme is used, i.e., using transistors for current amplification without electrical isolation, although the driving capability problem is solved, the threats of circuit ground potential crosstalk and high-voltage surges to the low-voltage control core remain unresolved, resulting in poor system safety. To address the problems of the prior art, the technical solution adopted in this application is to generate and output alternating conduction pulse signals, and control the on / off state of corresponding contacts in the polarity switching unit through an optocoupler-isolated driving module to generate the variable-direction driving current pulses. This scheme generates alternating conduction pulse signals, which can precisely control the energizing timing of the polarity switching unit coil. This ensures that the dual H-bridge outputs the correct and timely short pulse current to drive the magnetic latching relay, avoiding the risk of coil burnout due to continuous energizing. It also achieves precise matching of the magnetic latching relay characteristics. In addition, through the optocoupler isolation drive module, the control signal side (characterized by low voltage and susceptibility to interference) is electrically isolated from the power drive side (characterized by high voltage and high current). This effectively blocks the impact of high voltage, surge, and ground loop interference on the control core, ensuring the safety and stability of the control system.

[0019] In one embodiment of this application, the alternately conducting pulse signal can be a pulse width modulation signal. By adjusting the duty cycle of the pulse width modulation signal, the intensity of the drive current pulse can be controlled. During the process of generating the variable-direction drive current pulse in step S102, magnetic isolation can also be used to electrically isolate the control terminal of the pulse signal from the drive terminal of the polarity switching unit.

[0020] It should be noted that after a variable-direction drive current pulse is generated, if no arc suppression measures are taken, the contact arc will rapidly oxidize the contact material, increasing contact resistance and ultimately leading to control failure, which is a weak point in the reliability of the entire system. Furthermore, while using a varistor connected across the contacts of a magnetic latching relay to absorb surges can suppress overvoltage, its response characteristics are less effective than RC circuits in absorbing transient arc energy generated by frequent switching. Moreover, varistors are subject to aging, and their performance will degrade after repeated impacts. Therefore, in order to solve the problem that the polarity switching unit (i.e., dual relay) generates an electric arc when disconnecting an inductive load (magnetic latching relay coil), which leads to contact oxidation and ablation, thereby affecting the reliability and service life of the control circuit, this application can absorb the generated arc energy through an RC anti-sparking circuit connected in parallel to the contacts when the contacts in the polarity switching unit are disconnected after generating a variable-direction drive current pulse. Specifically, the absorption of the generated arc energy through the RC anti-sparking circuit connected in parallel to the contacts can be achieved by charging the capacitor in the RC anti-sparking circuit to limit the sudden change in voltage across the contacts, and by using a resistor to consume the energy stored in the capacitor. In the above-mentioned solution of this application, due to the introduction of protection measures for the control loop itself, the arc-breaking energy is actively absorbed through dynamic arc suppression, thus significantly reducing the probability of contact oxidation, thereby extending the mechanical life of the entire control core—the polarity switching unit, and improving the long-term stability of the system. Furthermore, by concretizing the arc suppression mechanism into the physical process of capacitor voltage limiting and resistor energy dissipation in the RC circuit, it has the characteristics of fast response, no polarity requirement, low cost and long life, providing an optimal and efficient way to realize the arc suppression function and ensuring the reliable achievement of the effect.

[0021] Step S103: Monitor the on / off state of the magnetic latching relay in real time by sampling the voltage of the magnetic latching relay contacts.

[0022] If it is assumed that the relay will always operate correctly after the drive pulse is issued, then this open-loop control scheme has a fatal flaw. This is because when faults such as contact sticking, insufficient drive energy, or mechanical jamming occur, the system cannot detect them and will mistakenly believe that the state has switched, potentially leading to a serious accident in the entire controlled system (e.g., an electric vehicle charging circuit), resulting in extremely low safety. Even using mechanical sensors to feedback the on / off state of the magnetic latching relay—that is, detecting the physical position of the contact mechanism through additional position sensors (e.g., microswitches, Hall effect sensors)—while state detection can be achieved, it increases additional hardware costs, installation complexity, and space occupation. Furthermore, the sensors themselves may fail, introducing new potential failure points. To address the above technical problems, the solution in this application is to sample the voltage of the magnetic latching relay contacts to monitor the on / off state of the magnetic latching relay in real time. By sampling this direct and reliable electrical parameter of contact voltage, the system can verify in real time whether the actual on / off state of the magnetic latching relay is consistent with the command. This upgrades the control scheme from an open-loop to a closed-loop system with verification capabilities, providing the most direct basis for system fault diagnosis, safety interlocking, and alarms, thereby improving the overall safety level and maintainability of the application system. Furthermore, this scheme requires no additional physical sensors; it only uses existing control circuitry to detect existing electrical signals, achieving the acquisition of the most critical status information at minimal additional cost.

[0023] Specifically, as one embodiment of this application, real-time monitoring of the on / off state of the magnetic latching relay by sampling the voltage of the magnetic latching relay contacts can be achieved by: comparing the voltage of the magnetic latching relay contacts with a preset threshold; determining whether the magnetic latching relay has successfully operated to the expected state based on the comparison result; if it is determined that the magnetic latching relay has not successfully operated to the expected state, then generating a variable-direction drive current pulse again through the control polarity switching unit until the magnetic latching relay successfully operates to the expected state. Figure 3 The diagram shown is a timing flowchart of the control method for a magnetic latching relay provided in this application embodiment. It intuitively describes the complete control logic from drive pulse triggering and state sampling to closed-loop judgment and the timing relationship between various signals. The above scheme achieves low-cost, high-reliability verification of the action result through intelligent analysis of the contact voltage. It can automatically retry when a failure is detected, improving the system's fault tolerance and robustness, and upgrading the control scheme from functional implementation to reliable assurance.

[0024] It should be noted that, Figure 1 The example method is compatible with both DC and AC power supply environments, using a polarity switching unit to rectify the AC power before supplying it to the coil of the magnetic latching relay. This is because... Figure 2The example dual H-bridge topology inherently possesses the hidden advantage of full-wave rectification. This innovative application allows the circuit to automatically adapt to AC / DC power supplies without any structural modifications or additional components, expanding the applicability of the solution and enabling circuit reuse.

[0025] From the above appendix Figure 1 As can be seen from the example of the magnetic latching relay control method, on the one hand, this application uses a double H-bridge topology structure composed of two single-pole double-throw relays cross-connected as the polarity switching unit, replacing the traditional semiconductor H-bridge. Since the relay contacts are mechanical contacts, their contact resistance when conducting is much lower than the conduction resistance of semiconductor devices. Therefore, the conduction loss in the current path of this solution is extremely low. The polarity switching unit only needs to consume a small amount of electrical energy to drive its coil at the moment of switching. Under steady state, neither the magnetic latching relay itself nor the polarity switching unit consumes any electrical energy, thereby achieving extremely low standby power consumption at the system level. At the same time, mechanical contacts are not easily affected by external electromagnetic interference. Their on / off state is determined by the mechanical structure, which has strong anti-interference ability and can effectively avoid malfunctions caused by interference in semiconductor solutions, significantly improving the reliability of the entire control path. On the other hand, this application uses ordinary, standardized single-pole double-throw relays to construct the core drive circuit, eliminating the need for expensive... High-power semiconductor switching transistors or dedicated driver chips are used, while ordinary relays, as mature and widely used basic components, offer significant cost advantages and have simple driving requirements. This solution effectively transforms the control problem of magnetic latching relays into a collaborative control problem of two common relays (ordinary relays and magnetic latching relays), simplifying circuit design and reducing the performance requirements of the core control components, thus contributing to overall cost control. Thirdly, this application monitors the on / off state of the magnetic latching relay contacts in real time by sampling the voltage, achieving direct feedback of the control results. This ensures the system is no longer operating blindly but can confirm whether the command has been correctly executed. Through this status feedback, control anomalies caused by contact sticking, drive failure, etc., can be identified in a timely manner, providing crucial information for further safety measures. This upgrades simple switching control to intelligent operation with preliminary fault diagnosis capabilities, enhancing the safety and maintainability of the entire controlled system. In summary, the technical solution of this application achieves low-power, high-reliability control of magnetic latching relays through a dual-relay H-bridge and status feedback.

[0026] Please see the appendix Figure 4 This application provides a magnetic latching relay control circuit for implementing the control method described above. The control circuit may include a polarity switching unit 401, a drive control unit 402, and a status feedback unit 403, as detailed below: The polarity switching unit 401 consists of two single-pole double-throw relays, whose contacts are cross-connected to form a double H-bridge topology. The two output terminals of the double H-bridge topology are used to connect the coils of the magnetic latching relays. The drive control unit 402 has its output connected to the coils of two single-pole double-throw relays in the polarity switching unit 401. It is used to receive control signals from an external controller and generate alternating conduction pulse signals to drive the polarity switching unit 402 to operate. The status feedback unit 403 has a sampling terminal for connecting to the contacts of the magnetic latching relay, and its output terminal provides a feedback signal characterizing the on / off state of the contacts.

[0027] From the above appendix Figure 4 As can be seen from the example magnetic latching relay control circuit, on the one hand, this application uses a double H-bridge topology structure composed of two single-pole double-throw relays cross-connected as the polarity switching unit, replacing the traditional semiconductor H-bridge. Since the relay contacts are mechanical contacts, their contact resistance when conducting is much lower than the conduction resistance of semiconductor devices. Therefore, the conduction loss in the current path of this solution is extremely low. The polarity switching unit only needs to consume a small amount of electrical energy to drive its coil at the moment of switching. Under steady state, neither the magnetic latching relay itself nor the polarity switching unit consumes any electrical energy, thus achieving extremely low standby power consumption at the system level. At the same time, mechanical contacts are not easily affected by external electromagnetic interference. Their on / off state is determined by the mechanical structure, which has strong anti-interference ability and can effectively avoid malfunctions caused by interference in semiconductor solutions, significantly improving the reliability of the entire control path. On the other hand, this application uses ordinary, standardized single-pole double-throw relays to construct the core drive circuit, eliminating the need for using more expensive... High-power semiconductor switching transistors or dedicated driver chips, along with ordinary relays as a mature, widely used basic component, offer significant cost advantages and have simple driving requirements. This solution effectively transforms the control problem of magnetic latching relays into a collaborative control problem of two common relays (ordinary relays and magnetic latching relays), simplifying circuit design and reducing the performance requirements of the core control components, thus contributing to overall cost control. Thirdly, this application monitors the on / off state of the magnetic latching relay contacts in real time by sampling the voltage, achieving direct feedback on the control results. This ensures the system is no longer operating blindly but can confirm whether the command has been correctly executed. Through this status feedback, control anomalies caused by contact sticking, drive failure, etc., can be identified in a timely manner, providing crucial information for further safety measures. This upgrades simple switching control to intelligent operation with preliminary fault diagnosis capabilities, enhancing the safety and maintainability of the entire controlled system. In summary, the technical solution of this application achieves low-power, high-reliability control of magnetic latching relays through a dual-relay H-bridge and status feedback.

[0028] In one embodiment of this application, Figure 2 or Figure 4 In the example polarity switching unit 401, each single-pole double-throw relay has an RC anti-sparking circuit connected in parallel across its contacts. The resistance and capacitance parameters of the RC anti-sparking circuit are matched and selected based on the operating current and inductance of the magnetic latching relay coil to optimize the arc suppression effect.

[0029] In one embodiment of this application, the status feedback unit 403 may include a voltage sampling circuit, a comparator circuit, and an analog-to-digital converter (ADC). The input terminal of the ADC is connected to the output terminal of the voltage sampling circuit, and the output terminal of the ADC is connected to the drive control unit. The voltage sampling circuit is used to divide and condition the contact voltage of the magnetic latching relay. The comparator circuit is used to compare the conditioned voltage with a reference voltage and output a high-level or low-level feedback signal. The ADC is used to convert the analog contact voltage value into a digital value for accurate judgment by the drive control unit 402. It should be noted that monitoring the health status of the contacts, such as whether there is increased contact resistance due to oxidation or ablation, or whether there are potential faults such as poor contact (i.e., loose connections), is crucial. These problems cannot be detected by simple on / off checks but will manifest as an abnormal increase in contact voltage drop. In the above embodiment, the introduction of the ADC is not an isolated action; it forms a closely coordinated digital monitoring system with the drive control unit 402. In scenarios requiring high reliability, such as electric vehicle charging and discharging management, the aforementioned combination of an analog-to-digital converter (ADC) and the drive control unit 402 can provide early warnings of relay aging, achieving a technical effect far superior to the on / off judgment of comparator circuits. In short, the ADC elevates the status feedback from binary judgment to precise analog monitoring. This allows the system to quantify the contact voltage drop, enabling early diagnosis of contact degradation trends. This represents a qualitative leap from status feedback to health status early warning, offering significant value for applications demanding high reliability and maintainability.

[0030] Considering that in complex and harsh electromagnetic environments (e.g., electric vehicle powertrain systems), optocoupler isolation alone may be insufficient to withstand surge currents and low-frequency strong electromagnetic interference from the power supply or load, leading to control malfunctions or damage. Even if the drive capability of the optocoupler isolation circuit is enhanced and transient suppression devices such as TVS diodes are added, the enhancement is only localized and does not fundamentally change the isolation method; its suppression effect on common-mode interference is not as good as magnetic isolation. To solve the above problems, Figure 4The example drive control unit 402 may also include a magnetic isolation protection module connected in series between the optocoupler-isolated drive module and the polarity switching unit 401 to protect against inrush current and electromagnetic interference. By superimposing the magnetic isolation protection module (e.g., isolation transformer, common-mode choke, etc.), a dual, heterogeneous isolation protection system is formed with the optocoupler isolation. Magnetic isolation is particularly adept at handling power supply noise and low-frequency interference, complementing the advantages of optocoupler isolation to provide the system with significantly stronger anti-interference and port protection capabilities than a single isolation method, ensuring the system's ultimate reliability in harsh industrial environments.

[0031] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application. The specific embodiments described above further illustrate the purpose, technical solutions, and beneficial effects of this application. It should be understood that the above descriptions are merely specific embodiments of this application and are not intended to limit the protection scope of this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A control method for a magnetic latching relay, characterized in that, The method includes: By controlling the polarity switching unit, a variable-direction drive current is provided to the coil of the magnetic latching relay. The polarity switching unit is composed of two single-pole double-throw relays cross-connected to form a double H-bridge topology. The alternating conduction pulse signal is generated and output, and the on / off state of the corresponding contact in the polarity switching unit is controlled by the optocoupler isolation drive module to generate the variable-direction drive current pulse. The on / off state of the magnetic latching relay is monitored in real time by sampling the voltage at the contacts of the magnetic latching relay.

2. The control method for a magnetic latching relay as described in claim 1, characterized in that, The method further includes: after generating the variable-direction drive current pulse, when the contacts in the polarity switching unit are opened, absorbing the generated arc energy through an RC anti-sparking circuit connected in parallel to the contacts.

3. The control method for a magnetic latching relay as described in claim 2, characterized in that, The absorption of generated arc energy by the RC anti-sparking circuit connected in parallel to the contacts includes: using the capacitor in the RC anti-sparking circuit to charge to limit the sudden change in voltage across the contacts, and using a resistor to consume the energy stored in the capacitor.

4. The control method for a magnetic latching relay as described in claim 1, characterized in that, The step of monitoring the on / off state of the magnetic latching relay in real time by sampling the voltage of the magnetic latching relay contacts includes: The voltage at the magnetic latching relay contact is compared with a preset threshold. The comparison results determine whether the magnetic latching relay has successfully operated to the expected state.

5. The control method for a magnetic latching relay as described in claim 4, characterized in that, The method further includes: if it is determined that the magnetic latching relay has not successfully operated to the expected state, then the variable-direction drive current pulse is generated again by controlling the polarity switching unit until the magnetic latching relay successfully operates to the expected state.

6. The control method for a magnetic latching relay as described in claim 1, characterized in that, The method is compatible with both DC and AC power supply environments. The AC power is rectified by the polarity switching unit and then used to power the coil of the magnetic latching relay.

7. A magnetic latching relay control circuit for implementing the control method as described in any one of claims 1 to 6, characterized in that, include: The polarity switching unit consists of two single-pole double-throw relays, whose contacts are cross-connected to form a double H-bridge topology. The two output terminals of the double H-bridge topology are used to connect to the coils of the magnetic latching relays. The drive control unit has its output connected to the coils of two single-pole double-throw relays in the polarity switching unit. It is used to receive control signals from an external controller and generate alternating conduction pulse signals to drive the polarity switching unit to operate. The status feedback unit has a sampling terminal for connecting to the contacts of the magnetic latching relay, and its output terminal provides a feedback signal characterizing the on / off state of the contacts.

8. The magnetic latching relay control circuit as described in claim 7, characterized in that, Each single-pole double-throw relay in the polarity switching unit has an RC anti-sparking circuit connected in parallel across its contacts. The resistance and capacitance parameters of the RC anti-sparking circuit are matched and selected according to the operating current and inductance of the magnetic latching relay coil to optimize the arc suppression effect.

9. The magnetic latching relay control circuit as described in claim 7, characterized in that, The state feedback unit includes a voltage sampling circuit, a comparator circuit, and an analog-to-digital converter. The input terminal of the analog-to-digital converter is connected to the output terminal of the voltage sampling circuit, and the output terminal of the analog-to-digital converter is connected to the drive control unit. The voltage sampling circuit is used to divide and condition the contact voltage of the magnetic latching relay; The comparator circuit is used to compare the conditioned voltage with the reference voltage and output the feedback signal at a high or low level. The analog-to-digital converter is used to convert the analog contact voltage value into a digital value for the drive control unit to make accurate judgments.

10. The magnetic latching relay control circuit as described in claim 7, characterized in that, The drive control unit also includes a magnetic isolation protection module, which is connected in series between the optocoupler isolation drive module and the polarity switching unit to resist surge current and electromagnetic interference.

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