Electromagnetic control switch on-off direct-current high-voltage large-current circuit

Abstract

The invention discloses an electromagnetic control switch on-off direct-current high-voltage large-current circuit, which belongs to the field of electromagnetic switches and comprises an electromagnetic control switch K1 and an electromagnetic control switch K2. One end of a wiring coil of the electromagnetic control switch K2 is connected with a control signal, and the other end of the wiring coil of the electromagnetic control switch K2 is connected with a power supply VCC; the other end of the wiring contact of the electromagnetic control switch K2 is connected with one end of the wiring contact of the electromagnetic control switch K1. The two ends of the wiring contact of the electromagnetic control switch K2 and the two ends of the resistor R1 are arranged in parallel. Two ends of the resistor R1 and two ends of the capacitor C2 are arranged in parallel; and one end of a wiring coil of the electromagnetic control switch K1 is connected with the anode of the diode D2. The arc energy is effectively reduced, the duration of the arc is inhibited, and the service life of the contact is prolonged; the risk of simultaneous arc discharge is reduced; and the potential safety hazards of long arc duration and serious contact ablation when the electromagnetic control switch cuts off direct current are avoided.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic switches, specifically to an electromagnetically controlled switch for switching high-voltage, high-current DC circuits. Background Technology

[0002] An electromagnetic switch is an electrical component that uses the principle of electromagnetism to control the on / off state of a circuit. The magnetic field generated by energizing a coil drives an armature to move, thereby connecting or disconnecting contacts. It is widely used in industrial control, home appliances, automotive electronics, and power systems, providing functions such as isolation control and automatic protection. Electromagnetic switches have the capacity to carry high current and high voltage; their mechanical contacts can withstand thousands of amperes of current and tens of thousands of volts of voltage, making them convenient for motor start-stop control. They offer excellent physical isolation safety; when the contacts are disconnected, an air-insulating gap is formed, completely cutting off the circuit without the leakage current risk associated with semiconductor devices. Electromagnetic switches also have good surge protection and EMC performance, with no risk of breakdown.

[0003] Existing electromagnetic control switches do not have a natural zero-crossing point for DC current when DC is switched on, which makes it difficult to extinguish the arc generated during switching. The arc lasts for a long time, and the contacts are severely eroded, which can easily cause safety hazards. Summary of the Invention

[0004] To address the aforementioned problems in the prior art, the present invention aims to provide an electromagnetically controlled switch for interrupting high-voltage, high-current DC circuits, thereby solving the problems of long arc duration and severe contact erosion.

[0005] To achieve the above objectives, the present invention provides the following technical solution: An electromagnetic control switch for switching a DC high-voltage, high-current circuit includes an electromagnetic control switch K1, an electromagnetic control switch K2, a resistor R1, a capacitor C2, and a diode D2. One end of the coil of the electromagnetic control switch K2 is connected to a control signal, and the other control signal is grounded. The other end of the coil of the electromagnetic control switch K2 is connected to the power supply VCC. One end of the contact of the electromagnetic control switch K2 is connected to the output signal, and the other end of the contact of the electromagnetic control switch K2 is connected to one end of the contact of the electromagnetic control switch K1. The other end of the contact of the electromagnetic control switch K1 is also connected to the output signal. The two ends of the wiring contacts of electromagnetic control switch K2 are connected in parallel with the two ends of resistor R1; the two ends of resistor R1 are connected in parallel with the two ends of capacitor C2. One end of the wiring coil of electromagnetic control switch K1 is connected to the anode of diode D2, and the cathode of diode D2 is connected to a control signal. The other end of the wiring coil of the electromagnetic control switch K1 is connected to the power supply VCC.

[0006] As a further aspect of the present invention: a diode D3 is connected in parallel across the two ends of the wiring coil of the electromagnetic control switch K2.

[0007] As a further aspect of the present invention, the cathode of the diode D3 is connected to the power supply VCC.

[0008] As a further aspect of the present invention: a diode D1 is connected in parallel across the two ends of the wiring coil of the electromagnetic control switch K1.

[0009] As a further aspect of the present invention, the cathode of the diode D1 is connected to the power supply VCC.

[0010] As a further aspect of the present invention: the two non-connected wiring contacts of the electromagnetic control switches K1 and K2 are connected to the external output OUT.

[0011] As a further aspect of the present invention: the capacitor C2 is an arc-extinguishing capacitor, the resistor R1 is a discharge resistor, and the arc-extinguishing capacitor C2 and the discharge resistor R1 constitute a DC interruption working circuit.

[0012] As a further aspect of the present invention: the capacitor C1 and the diode D2 constitute the delay control loop of the electromagnetic control switch K1.

[0013] As a further aspect of the present invention, the value of the capacitor C2 satisfies: C2≥I²·t / (V²·k), where I is the breaking current, t is the required arc extinguishing time, V is the system voltage, and k is the safety factor.

[0014] As a further aspect of the present invention, the value of the resistor R1 satisfies: R1≤V / (10·I); where I is the interrupting current and V is the system voltage.

[0015] Compared with the prior art, the beneficial effects of the present invention are: This invention effectively reduces arc energy, suppresses arc duration, and extends contact life; ensures staggered shutdown of dual relays, reducing the risk of simultaneous arcing; avoids reverse voltage damage; and prevents prolonged arc duration and severe contact erosion during DC interruption by electromagnetic control switches. Through a dual-relay collaborative control strategy, combined with an optimized arc-extinguishing capacitor and bleeder resistor network, and precise timing control circuitry, this invention achieves efficient and reliable interruption of high-voltage, high-current DC circuits while maintaining miniaturization and low cost. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of an electromagnetic control switch for switching high-voltage, high-current DC circuits, as disclosed in an embodiment. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "connected," and "linked" should be interpreted broadly; for example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0019] Small electromagnetic control switches typically have different performance parameters for AC and DC operating circuits. This is because in AC circuits, the current has a natural zero-crossing point, allowing the arc between the contacts to extinguish itself easily during the switching process, resulting in strong voltage and current breaking capacity. However, in DC circuits, the current lacks a zero-crossing point, causing the arc between the contacts to fail to extinguish itself. Prolonged arcing can burn out the electromagnetic control switch, so the nominal DC breaking voltage or current parameters of electromagnetic control switches are usually much lower than their AC parameters. The main difference lies in breaking capacity; the operating circuit only performs closing, so AC and DC have equivalent capabilities. This circuit, by introducing a transition capacitor and auxiliary circuitry, enables the small electromagnetic control switch to achieve DC breaking capacity equal to its AC voltage and current parameters.

[0020] Please see Figure 1 An electromagnetic control switch for switching a DC high-voltage, high-current circuit includes an electromagnetic control switch K1, an electromagnetic control switch K2, a resistor R1, a capacitor C1, a capacitor C2, a diode D1, a diode D2, and a diode D3; one end of the wiring coil of the electromagnetic control switch K2 is connected to a control signal, and the other control signal is grounded; The other end of the wiring coil of electromagnetic control switch K2 is connected to power supply VCC; Diode D3 is connected in parallel across the coil of electromagnetic control switch K2; The cathode of diode D3 is connected to the power supply VCC; One end of the wiring contact of electromagnetic control switch K2 is connected to the output signal, and the other end of the wiring contact of electromagnetic control switch K2 is connected to one end of the wiring contact of electromagnetic control switch K1, and the other end of the wiring contact of electromagnetic control switch K1 is connected to the output signal. The two ends of the wiring contacts of the electromagnetic control switch K2 and the two ends of the resistor R1 are connected in parallel; The two ends of resistor R1 and the two ends of capacitor C2 are connected in parallel; One end of the wiring coil of electromagnetic control switch K1 is connected to the anode of diode D2, and the cathode of diode D2 is connected to a control signal. The other end of the wiring coil of the electromagnetic control switch K1 is connected to the power supply VCC; Diode D1 is connected in parallel across the terminals of the coil of electromagnetic control switch K1; The cathode of diode D1 is connected to the power supply VCC; A capacitor C1 is connected in parallel across the two ends of diode D1; the two non-connected terminals of electromagnetic control switches K1 and K2 are connected to the external output OUT.

[0021] Capacitor C2 is an arc-extinguishing capacitor, and resistor R1 is a bleeder resistor. The arc-extinguishing capacitor C2 and the bleeder resistor R1 constitute the working circuit for realizing DC interruption; capacitor C1 and diode D2 constitute the delay control loop of K1.

[0022] This circuit consists of two small electromagnetic control switches K1 and K2, an arc-extinguishing capacitor C2, and a bleeder resistor R1, forming a working circuit that can realize DC interruption; capacitor C1 and diode D2 form a delay control circuit for electromagnetic control switch K1.

[0023] This invention employs a dual-relay graded interruption technology: K2 disconnects first, transferring the current to the arc-extinguishing network; K1 then disconnects, achieving complete isolation. Optimized arc extinguishing network parameter design: The value of capacitor C2 satisfies: C2≥I²·t / (V²·k), where I is the breaking current, t is the required arc extinguishing time, V is the system voltage, and k is the safety factor. Arc extinguishing capacitor C2 absorbs inductive energy at the moment K2 is turned off, suppressing the generation of arc. Through its capacitive characteristics, it slows down the voltage rise rate (dv / dt), reducing the risk of breakdown between contacts.

[0024] The value of resistor R1 satisfies: R1≤V / (10·I); the discharge resistor R1 releases the energy stored in C2, avoiding secondary breakdown caused by the accumulation of capacitor voltage; and converts the arc energy into heat energy for consumption.

[0025] The present invention uses a delay circuit composed of capacitor C1 and diode D2 to ensure that K1 operates later than K2, thereby precisely controlling the timing.

[0026] This invention employs a multi-protection design with coil protection diodes D1 and D3, and contact buffer capacitor C1.

[0027] In this invention, electromagnetic control switches K1 and K2 serve as main switching elements, responsible for the conduction and cutoff of current; arc-extinguishing capacitor C2 and bleeder resistor R1 suppress arcs and protect contacts; delay capacitor C1 and control diode D2 optimize the switching sequence of the relay; protection diodes D1 and D3 prevent reverse voltage of the coil from damaging the circuit.

[0028] The function of the pre-charge relay K2 is to operate before relay K1, undertaking the initial current conduction and switching tasks; during switching off, it first transfers the current to the arc extinguishing network, reducing the burden on relay K1. The contacts of relay K2 are connected in series with relay K1 to ensure that K1 switches off under low current conditions, reducing arc damage.

[0029] The function of the main relay K1 is to completely cut off the circuit after the relay K2 completes its pre-turn-off. Since relay K2 has already transferred most of the current, the arc energy when relay K1 turns off is significantly reduced. Through the delay control of diode D2 and capacitor C1, it is ensured that relay K1 operates 5-10ms later than relay K2.

[0030] The delay capacitor C1 and diode D2 work together to form an RC delay circuit, which causes the coil voltage of relay K1 to drop slowly, ensuring that relay K1 disconnects 5-10ms later than K2, thus preventing both relays from turning off at the same time.

[0031] When the control signal is removed, the control diode D2 blocks the rapid discharge path of C1, forcing the current to be released slowly through the K1 coil; thus ensuring the delayed turn-off action of the relay K1.

[0032] Protection diode D1 is connected in parallel across the coil of relay K1 to absorb the reverse electromotive force peak voltage generated when the relay is turned off, preventing high-voltage pulses from damaging the drive circuit. Diode D3 functions the same as diode D1, protecting the coil of relay K2 from reverse peak voltage surges.

[0033] Capacitor C1 acts as a buffer, connected in parallel across diode D1 to further smooth coil voltage fluctuations and reduce electromagnetic interference when the relay operates.

[0034] Relays K1 and K2 are designed with series contacts to form a dual breaking mechanism of "breaking first and then breaking": Relay K2, as the pilot relay, breaks first and transfers the current to the arc-extinguishing branch; Relay K1, as the main relay, completes the final breaking after the current has been limited; This timing difference design ensures that the arc energy is consumed in stages.

[0035] The capacitor C2 in the RC network connected across the K2 contact provides a transient current path and absorbs the electromagnetic energy generated when the contact is opened; the resistor R1 limits the capacitor discharge current and consumes the stored energy.

[0036] The timing control circuit controls the delayed action of relay K1. Diode D2 blocks the fast discharge circuit when the control signal is removed. Capacitor C1 and the relay coil form an RC delay circuit with a typical delay of 5-10ms, ensuring that K2 completes its action first.

[0037] The protective components connected in parallel across the coil are: diodes D1 and D3, which provide a freewheeling path when the coil is de-energized, suppress back electromotive force, and protect the drive circuit; capacitor C1 helps absorb high-frequency interference and enhances anti-interference capability.

[0038] All relay coils share a common power supply, with the diode cathodes connected to VCC to ensure consistent protection. Power supply decoupling design reduces interference.

[0039] The circuit operates as follows: During the closing process, the control terminals of miniature electromagnetic control switches K1 and K2 are powered on, the relay electromagnet is attracted, and the contacts of miniature electromagnetic control switches K1 and K2 close, thus activating the working circuit. Simultaneously, the power supply at the control terminals charges capacitor C1.

[0040] In the opening and closing process, the power supply to the control terminals of miniature electromagnetic control switches K1 and K2 is disconnected. Capacitor C1 supplies power to miniature electromagnetic control switch K1, which delays the opening process and remains closed. Simultaneously, the contacts of relay K2 open, and the working circuit current flows through the bypass capacitor C2. At this time, the current between the contacts of miniature electromagnetic control switch K2 is extremely small, and the voltage is low. Capacitor C2 is in the charging process and can be easily disconnected. As capacitor C2 is fully charged, the working circuit current decreases. With the discharge of capacitor C1 completed, miniature electromagnetic control switch K1 opens. At this time, the current in the working circuit is very small, and miniature electromagnetic control switch K1 can be easily disconnected, thus successfully completing the DC breaking process.

[0041] In the circuit, after the working circuit is completely disconnected, the voltage across capacitor C2 remains high, reaching the working circuit voltage. Resistor R1 is used to discharge the residual voltage of capacitor C2, preparing for subsequent closing.

[0042] After the power supply to the control terminals of the miniature electromagnetic control switches K1 and R1K2 is disconnected, capacitor C1 discharges through R1K1 to maintain the process, while D2 isolates the control terminals of the miniature electromagnetic control switches K1 and K2.

[0043] In the circuit, the parameters of capacitor C1, capacitor C2, and resistor R1 need to be adjusted and matched according to the parameters of the small relay itself, the voltage and current of the working circuit, and the control action time requirements to meet the overall requirements of the functional circuit.

[0044] In this invention, capacitor C2 and resistor R1 effectively reduce arc energy, suppress the duration of arc, and extend contact life; capacitor C1 and diode D2 ensure that relays K1 and K2 are turned off at off-peak times, reducing the risk of simultaneous arcing; diodes D1 and D3 prevent damage from reverse voltage; through proper selection, high-voltage and high-current interruption can be achieved in a small volume.

[0045] This invention discloses an electromagnetic control switch circuit for interrupting high-voltage, high-current DC signals. Through dual-relay coordinated control combined with an optimized arc-extinguishing network, reliable interruption of a small electromagnetic control switch under high-voltage, high-current DC conditions is achieved. This circuit has advantages such as simple structure, low cost, and high reliability, and is suitable for applications in new energy power generation, electric vehicles, and industrial control.

[0046] This invention, through an innovative dual-relay structure combined with optimized arc-extinguishing and timing control circuits, achieves reliable interruption of a small electromagnetic control switch under DC high voltage and high current conditions, solving the technical problems of long arc duration and severe contact erosion during DC interruption caused by traditional single relays. This invention, through an innovative dual-relay collaborative control strategy, combined with an optimized arc-extinguishing capacitor and bleeder resistor network, and precise timing control circuitry, achieves efficient and reliable interruption of DC high voltage and high current while ensuring miniaturization and low cost.

[0047] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered exemplary and not restrictive in all respects. The scope of the invention is defined by the appended claims rather than the foregoing description, and therefore all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0048] 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. An electromagnetically controlled switch for interrupting high-voltage, high-current DC circuits, characterized in that, It includes an electromagnetic control switch K1, an electromagnetic control switch K2, a resistor R1, a capacitor C2, and a diode D2; one end of the wiring coil of the electromagnetic control switch K2 is connected to a control signal, and the other control signal is grounded; the other end of the wiring coil of the electromagnetic control switch K2 is connected to the power supply VCC; one end of the wiring contact of the electromagnetic control switch K2 is connected to the output signal, and the other end of the wiring contact of the electromagnetic control switch K2 is connected to one end of the wiring contact of the electromagnetic control switch K1, and the other end of the wiring contact of the electromagnetic control switch K1 is connected to the output signal; The two ends of the wiring contacts of electromagnetic control switch K2 are connected in parallel with the two ends of resistor R1; the two ends of resistor R1 are connected in parallel with the two ends of capacitor C2. One end of the wiring coil of the electromagnetic control switch K1 is connected to the anode of the diode D2, and the cathode of the diode D2 is connected to a control signal; a capacitor C1 is connected in parallel across the two ends of the wiring coil of the electromagnetic control switch K1. The other end of the wiring coil of the electromagnetic control switch K1 is connected to the power supply VCC.

2. The electromagnetic control switch for interrupting high-voltage, high-current DC circuits according to claim 1, characterized in that, A diode D3 is connected in parallel across the two ends of the wiring coil of the electromagnetic control switch K2.

3. The electromagnetic control switch for interrupting high-voltage, high-current DC circuits according to claim 2, characterized in that, The cathode of diode D3 is connected to the power supply VCC.

4. The electromagnetic control switch for interrupting high-voltage, high-current DC circuits according to claim 3, characterized in that, A diode D1 is connected in parallel across the two ends of the wiring coil of the electromagnetic control switch K1.

5. The electromagnetic control switch for interrupting high-voltage, high-current DC circuits according to claim 4, characterized in that, The cathode of diode D1 is connected to the power supply VCC.

6. The electromagnetic control switch for interrupting high-voltage, high-current DC circuits according to claim 5, characterized in that, The two non-connected wiring contacts of the electromagnetic control switches K1 and K2 are connected to the external output OUT.

7. The electromagnetic control switch for interrupting high-voltage, high-current DC circuits according to claim 6, characterized in that, The capacitor C2 is an arc-extinguishing capacitor, and the resistor R1 is a discharge resistor. The arc-extinguishing capacitor C2 and the discharge resistor R1 constitute a DC interruption working circuit.

8. The electromagnetic control switch for interrupting high-voltage, high-current DC circuits according to claim 7, characterized in that, The capacitor C1 and diode D2 constitute the delay control loop of the electromagnetic control switch K1.

9. The electromagnetic control switch for interrupting high-voltage, high-current DC circuits according to claim 8, characterized in that, The value of capacitor C2 satisfies: C2≥I²·t / (V²·k), where I is the breaking current, t is the required arc extinguishing time, V is the system voltage, and k is the safety factor.

10. The electromagnetic control switch for interrupting high-voltage, high-current DC circuit according to claim 9, characterized in that, The value of resistor R1 satisfies: R1≤V / (10·I); where I is the interrupting current and V is the system voltage.

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