Direct-current dual-power-supply switching device

Abstract

The invention relates to a DC dual power supply switching device, and relates to the technical field of power supply guarantee, the DC dual power supply switching device comprises a first input power supply module, a second input power supply module, a power supply switching module and an output power supply module, the power supply switching module is connected between the first input power supply module and the output power supply module and between the second input power supply module and the output power supply module; the power supply switching module comprises a trigger pulse generating circuit and a magnetic latching relay switching circuit, and the trigger pulse generating circuit can trigger the magnetic latching relay switching circuit according to the power supply state of the first input power supply module, so that the output power supply module is connected with the first input power supply module; according to the dual-power-supply switching power supply device, the reliability of the dual-power-supply switching power supply device can be improved, and the continuous power supply effect of dual power supplies is ensured.

Description

Technical Field

[0001] The present application relates to the technical field of power supply assurance, and in particular to a DC dual power supply switching device. Background Art

[0002] The stable operation of the power system is of vital importance. Many key equipment requires a continuous power supply. Once the power supply is interrupted, a large amount of economic losses will be incurred at the least, and people's lives and even the overall security of the country will be affected at the worst. However, the power system and the electrical equipment connected to the power system are bound to fail. Once a failure occurs that can affect the stable operation of the power system, it is usually necessary to isolate the faulty part from the power system in time to ensure the normal operation of other parts of the power system, prevent the scope of the fault from expanding, and even cause the power grid to be paralyzed. Therefore, control and protection devices are usually set up in the power system, such as relay protection equipment and automatic monitoring systems in substations. The automatic monitoring system is used to detect the operating status of the power system. Once a fault is detected, the relay protection equipment will act in time to disconnect the faulty part from the power system to avoid affecting the normal operation of the entire power system and maintain the stability and safety of the power system.

[0003] In order to be able to promptly discover and deal with faulty parts in the power system, it is necessary to ensure the continuous and uninterrupted operation of the control and protection device, so it is necessary to ensure the uninterrupted power supply of the control and protection device. The control and protection device is usually powered by the DC power supply of the power system, and the DC power supply of the power system may fail due to various reasons, such as aging of electronic components, poor heat dissipation, etc. In addition, the DC bus (a conductor that collects and distributes DC power) of the power system may also have faults such as short circuits. In order to ensure that the failure of the power supply does not affect the continuous operation of the control and protection device, the control and protection device is usually equipped with a dual power switching power supply device for power supply. Once one power supply fails, it automatically and quickly switches to another power supply to power the control and protection device, ensuring that the power supply of the control and protection device will not be interrupted.

[0004] The existing dual power switching power supply device usually sets a relay in each of the two power supply circuits, and combines the relay contacts in the two power supply circuits into an output power supply circuit to supply power to the control protection device. The power consumption of the control protection device is relatively large, usually 10-20 amperes, which requires the relay to have a large power supply load. Large current switching can easily cause damage to the relay contacts. Moreover, the coil current of a large-load relay is usually also large. The relay coil is connected to the power circuit for a long time and bears a large current, which can easily cause damage to the switching relay, affecting the normal operation of the dual power switching power supply device. Summary of the invention

[0005] In order to improve the reliability of a dual-power switching power supply device and ensure the continuous power supply effect of the dual power supplies, the present application provides a DC dual-power switching device.

[0006] The DC dual power supply switching device provided in this application adopts the following technical solution: A DC dual power switching device comprises a first input power module, a second input power module, a power supply switching module and an output power module, wherein the power supply switching module is connected between the first input power module, the second input power module and the output power module, and the power supply switching module comprises a trigger pulse generating circuit and a magnetic latching relay switching circuit, wherein the trigger pulse generating circuit can trigger the magnetic latching relay switching circuit according to the power supply state of the first input power module, so that the output power module is connected to the first input power module, or to the second input power module.

[0007] By adopting the above technical solution, using a power supply switching module composed of a trigger pulse generating circuit and a magnetic latching relay switching circuit, the power supply state change of the first input power module and / or the second input power module can be converted into a trigger pulse, and can be used to trigger the magnetic latching relay switching circuit to switch the connection between the output power module and the first input power module and the second input power module; using the magnetic latching relay switching circuit, the output of a large current DC power supply can be increased through the magnetic latching relay, and when the trigger pulse generating circuit does not generate a trigger signal, no current flows through the relay coil, thereby reducing the energy consumption of the magnetic latching relay and extending the service life of the magnetic latching relay.

[0008] In a specific feasible implementation scheme, the first input power module includes a first input power circuit, a first trigger relay circuit and a first input power indication circuit, the first input power circuit is connected to a first DC power supply, the first trigger relay circuit and the first input power indication circuit are connected to the first input power circuit, the first trigger relay circuit includes a first trigger relay, the first trigger relay can change the working state according to the power supply state of the first input power circuit, so that the trigger pulse generating circuit generates a trigger pulse, and the first input power indication circuit can indicate the power supply state of the first input power circuit; the second input power module includes a second input power circuit, a second trigger relay circuit and a second input power indication circuit, the second input power circuit is connected to a second DC power supply, the second trigger relay circuit and the second input power indication circuit are connected to the second input power circuit, the second trigger relay circuit includes a second trigger relay, the second trigger relay can change the working state according to the power supply state of the second input power circuit, and the second input power indication circuit can indicate the power supply state of the second input power circuit.

[0009] By adopting the above technical scheme, by utilizing the setting of the first input power indication circuit and the second input power indication circuit, the power supply status of the first input power circuit and the second input power circuit can be intuitively indicated, so that the working status of the first DC power supply and the second DC power supply can be conveniently monitored; by utilizing the first trigger relay connected in the first input power circuit and the second trigger relay connected in the second input power circuit, the power supply status of the input power circuit can be monitored by a smaller current flowing through the trigger relay coil, and a smaller trigger current signal can be output to the trigger pulse generating circuit when the power supply status changes, so that the first trigger relay and the second trigger relay can work online for a long time, thereby ensuring the service life of the first trigger relay and the second trigger relay.

[0010] In a specific feasible implementation scheme, the first trigger relay circuit and the first input power indication circuit are connected in series and then connected to the first input power circuit; the second trigger relay circuit and the second input power indication circuit are connected in series and then connected to the second input power circuit.

[0011] By adopting the above technical solution and utilizing the setting in which the trigger relay circuit and the input power indication circuit are connected in series, it is possible to ensure the synchronous change of the working states of the trigger relay circuit and the input power indication circuit, limit the working voltage and working current of the trigger relay, and extend the service life of the trigger relay.

[0012] In a specific implementation scheme, the first trigger relay circuit includes a diode D11, a trigger relay coil RLA2, a resistor RD1 and a diode D12, the anode of the diode D11 is connected to the anode of the first input power circuit, the cathode of the diode D11 is connected to the trigger relay coil RLA2, the trigger relay coil RLA2 is connected to the first input power indication circuit, the resistor RD1 is connected in series with the diode D12 and then connected in parallel with the trigger relay coil RLA2, and the cathode of the diode D12 is connected to the cathode of the diode D11; the first input power indication circuit includes a light-emitting diode H1, a resistor RH1 and a resistor R11, the anode of the light-emitting diode H1 is connected to the trigger relay coil RLA2, the resistor R11 is connected between the cathode of the light-emitting diode H1 and the cathode of the first input power circuit, and the resistor RH1 is connected to the light-emitting diode H1 is connected in parallel; the second trigger relay circuit includes a diode D21, a trigger relay coil RLA3, a resistor RD2 and a diode D22, the anode of the diode D21 is connected to the anode of the second input power circuit, the cathode of the diode D21 is connected to the trigger relay coil RLA3, the trigger relay coil RLA3 is connected to the second input power indication circuit, the resistor RD2 is connected in series with the diode D22 and then connected in parallel with the trigger relay coil RLA3, and the cathode of the diode D22 is connected to the cathode of the diode D21; the second input power indication circuit includes a light-emitting diode H2, a resistor RH2 and a resistor R21, the anode of the light-emitting diode H2 is connected to the trigger relay coil RLA3, the resistor R21 is connected between the cathode of the light-emitting diode H2 and the cathode of the second input power circuit, and the resistor RH2 is connected in parallel with the light-emitting diode H2.

[0013] By adopting the above technical scheme, by using the resistor RD1 and the diode D12 connected in parallel with the trigger relay coil RLA2, and the resistor RD1 and the diode D12 connected in parallel with the trigger relay coil RLA2, the induced electromotive force generated in the coil when the power supply state changes can be quickly eliminated, the trigger time delay of the trigger relay can be reduced, and the trigger time sensitivity of the trigger relay can be improved; by using the resistor RH1 connected in parallel with the light-emitting diode H1, and the resistor RH2 connected in parallel with the light-emitting diode H2, a power supply circuit can be provided for the coil of the trigger relay when the light-emitting diode fails and opens, thereby avoiding the trigger relay circuit from losing function. At the same time, the resistor RH1 and the resistor RH2 can also form a voltage divider circuit with the resistor R11 and the resistor R21 respectively to adjust the light brightness of the light-emitting diode H1 and the light-emitting diode H2 respectively.

[0014] In a specific feasible implementation scheme, the trigger pulse generating circuit includes a diode D13, a trigger relay contact group RL2B, a capacitor C1, a resistor R1 and a resistor R3, the trigger relay contact group RL2B includes a moving contact K1, a normally closed static contact K2 and a normally open static contact K3, the diode D13 is connected between the positive pole of the first input power circuit and the normally open static contact K3, one end of the capacitor C1 is connected to the moving contact K1, and the other end is connected to the resistor R1, the other end of the resistor R1 is connected to the magnetic holding relay switching circuit, the resistor R3 is connected between the normally closed static contact K2 and the negative pole of the first input power circuit, and the trigger relay contact group RL2B can change the connection state according to the action of the first trigger relay.

[0015] By adopting the above technical solution, using the trigger pulse generating circuit composed of the diode D13, the trigger relay contact group RL2B, the capacitor C1, the resistor R1 and the resistor R3, when the first trigger relay is actuated, the contact of the trigger relay contact group RL2B changes, so that the diode D13 is connected to the capacitor C1, the first DC power supply charges the capacitor C1 through the diode D13, the resistor R1 and the magnetic latching relay switching circuit, and a charging pulse current is generated in the magnetic latching relay switching circuit, triggering the magnetic latching relay switching circuit to generate a switching action; and when the first trigger relay loses power, the contact of the trigger relay contact group RL2B changes, so that the resistor R3 is connected to the capacitor C1, the capacitor C1 is discharged through the resistor R3, the magnetic latching relay switching circuit and the resistor R1, and a discharge pulse current is generated in the magnetic latching relay switching circuit, triggering the magnetic latching relay switching circuit to generate a reverse switching action.

[0016] In a specific implementation scheme, the magnetic latching relay switching circuit includes a magnetic latching relay coil RL1A, a resistor R2, a normally closed contact group RL1B, a normally open contact group RL1C, a normally closed contact group RL1D and a normally open contact group RL1E, the magnetic latching relay coil RL1A is connected between the resistor R1 and the negative electrode of the first input power circuit, the resistor R2 is connected in parallel with the magnetic latching relay coil RL1A, the normally closed contact group RL1B is connected between the positive electrode of the second input power circuit and the positive electrode of the output power module, and the normally The open contact group RL1C is connected between the positive pole of the first input power circuit and the positive pole of the output power module, the normally closed contact group RL1D is connected between the negative pole of the second input power circuit and the negative pole of the output power module, the normally open contact group RL1E is connected between the negative pole of the first input power circuit and the negative pole of the output power module, and the normally closed contact group RL1B, the normally open contact group RL1C, the normally closed contact group RL1D and the normally open contact group RL1E can change the open and closed state under the action of the trigger pulse in the magnetic holding relay coil RL1A.

[0017] By adopting the above technical scheme, by utilizing the magnetic latching relay coil RL1A connected between the resistor R1 and the negative pole of the first input power circuit, it is possible to switch and maintain the connection states of the normally closed contact group RL1B, the normally closed contact group RL1D, the normally open contact group RL1C and the normally open contact group RL1E of the large current load under the action of pulse currents in different directions, while no current passes through under normal conditions, thereby effectively extending the service life of the magnetic latching relay and reducing energy consumption; by utilizing the resistor R2 connected in parallel with the magnetic latching relay coil RL1A, it is possible to quickly eliminate the induced electromotive force generated when the pulse current passes through the magnetic latching relay coil RL1A, and participate in controlling the magnitude and duration of the voltage formed at both ends of the magnetic latching relay coil RL1A by the charging and discharging of the capacitor C1.

[0018] In a specific feasible implementation scheme, a diode D23 is provided on the connection line connecting the positive electrode of the output power module and the second input power module, a diode D14 is provided on the connection line connecting the positive electrode of the output power module and the first input power module, a diode D24 is provided on the connection line connecting the negative electrode of the output power module and the second input power module, and a diode D15 is provided on the connection line connecting the negative electrode of the output power module and the first input power module.

[0019] By adopting the above technical solution, by using the diodes D14, D15, D23 and D24 arranged between the output power module and the first input power module and the second input power module, it is possible to prevent a circuit short circuit failure inside the switching device caused by reverse connection of the positive and negative poles between the first input power module and the first DC power supply, or between the second input power module and the second DC power supply.

[0020] In a specific feasible implementation scheme, the output power supply module includes a first power supply indication circuit and a second power supply indication circuit, the first power supply indication circuit includes a resistor R12, a resistor RH3 and a light-emitting diode H3, one end of the resistor R12 is connected to the positive electrode of the diode D14, and the other end is connected to the light-emitting diode H3, the other end of the light-emitting diode H3 is connected to the negative electrode of the diode D15, and the resistor RH3 is connected in parallel with the light-emitting diode H3; the second power supply indication circuit includes a resistor R22, a resistor RH4 and a light-emitting diode H4, one end of the resistor R22 is connected to the positive electrode of the diode D23, and the other end is connected to the light-emitting diode H4, the other end of the light-emitting diode H4 is connected to the negative electrode of the diode D24, and the resistor RH4 is connected in parallel with the light-emitting diode H4.

[0021] By adopting the above technical solution, using the first power supply indication circuit and the second power supply indication circuit, the input power supply module connected to the output power supply module can be intuitively indicated, thereby intuitively indicating which DC power supply of the first DC power supply and the second DC power supply is used as the current power supply.

[0022] In a specific implementation scheme, the output power module further includes a diode protection circuit, and the diode protection circuit includes a diode bridge BR5, and the diode bridge BR5 is connected between the positive electrode and the negative electrode of the output power module.

[0023] By adopting the above technical solution, using the diode bridge BR5 connected between the positive and negative electrodes of the output power module, it is possible to smooth out the voltage spikes and current mutations caused by the induced electromotive force generated by the relay coil or the switching of the relay contacts between the positive and negative electrodes of the output power module, thereby reducing the damage caused to the circuit.

[0024] In a specific implementation scheme, the DC dual power supply switching device of the present application further includes an alarm trigger module, which can generate an alarm signal when the first input power module or the second input power module loses power.

[0025] By adopting the above technical solution and utilizing the alarm trigger module, an alarm signal can be generated when the first input power module or the second input power module loses power, indicating the power shortage caused by the failure of the first DC power supply, the second DC power supply, the first input power module or the second input power module, thereby ensuring that the two DC power supplies are in an effective redundant power supply state.

[0026] In summary, the present application includes at least one of the following beneficial technical effects: By using a magnetic latching relay as a switching device of the switching circuit, not only can the power supply be smoothly switched under a large current load, but also a pulse signal can be used as a switching trigger signal of the magnetic latching relay, so that there is no need to continuously pass current through the coil of the magnetic latching relay, thus avoiding the heating and aging of the coil of the magnetic latching relay under the action of continuous current, effectively improving the service life of the switching device and ensuring the reliability of the dual power switching device; By setting the pulse generating circuit, a trigger signal can be generated when the power supply state of the first input power supply module changes, and the voltage and trigger time of the trigger signal are controlled to ensure the reliable triggering of the magnetic latching relay, thereby effectively ensuring the reliability of the switching of the power supply switching module; By setting the input power indication circuit and the power supply indication circuit, the power supply status of the two power supply DC power supplies and the power supply currently connected to the output power module can be displayed, and the working status of the two power supply DC power supplies can be intuitively indicated, which is conducive to the staff to grasp the working status of the dual power supply switching device and the two power supplies at any time; The alarm trigger module can be used to give an alarm message when the first input power module or the second input power module loses power, reminding the staff to deal with it in time, which is conducive to keeping both power supply circuits ready to supply power at any time, ensuring that the output power module can output power at any time, and the control and protection device that monitors the power system status can be powered uninterruptedly. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a working principle diagram of an embodiment of the present application.

[0028] Figure 2 This is a main circuit diagram in one embodiment of the present application.

[0029] Figure 3 This is a voltage waveform diagram across the coil RL1A of the magnetic latching relay when the capacitor C1 is in a charging state in one embodiment of the present application.

[0030] Figure 4 This is a voltage waveform diagram across the coil RL1A of the magnetic latching relay when the capacitor C1 is in the discharge state in one embodiment of the present application.

[0031] Figure 5This is a voltage waveform diagram across the output power module during the process of switching from a connection state with the second input power module to a connection state with the first input power module in one embodiment of the present application.

[0032] Figure 6 This is a voltage waveform diagram across the output power module during the process of switching from a connection state with a first input power module to a connection state with a second input power module in one embodiment of the present application.

[0033] Explanation of the accompanying drawings: 1. First input power module; 11. First input power circuit; 12. First trigger relay circuit; 121. First trigger relay; 13. First input power indication circuit; 2. Second input power module; 21. Second input power circuit; 22. Second trigger relay circuit; 221. Second trigger relay; 23. Second input power indication circuit; 3. Power supply switching module; 31. Trigger pulse generating circuit; 32. Magnetic holding relay switching circuit; 4. Output power module; 41. First power supply indication circuit; 42. Second power supply indication circuit; 43. Diode protection circuit; 5. Alarm trigger module. DETAILED DESCRIPTION

[0034] The specific implementation of the present application is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present application, and is not used to limit the present application.

[0035] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "disposed" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0036] In this specification, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or suggesting relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the said features.

[0037] An embodiment of the DC dual power switching device of the present application is as follows: Figure 1 and Figure 2As shown, it includes a first input power module 1, a second input power module 2, a power supply switching module 3 and an output power module 4. The first input power module 1 and the second input power module 2 are each connected to a DC power supply, and can detect the power supply status of the connected DC power supply. The power supply switching module 3 is connected between the first input power module 1, the second input power module 2 and the output power module 4, and can switch the output power module 4 to be connected to the first input power module 1 or to the second input power module 2 according to the power supply status of the first input power module 1 and the second input power module 2, so as to control whether the output power module 4 is powered by the first DC power supply connected to the first input power module 1 or the second DC power supply connected to the second input power module 2, so as to ensure that the output power module 4 can output the DC power uninterruptedly, thereby ensuring that the control protection device can work reliably and continuously.

[0038] The power supply switching module 3 includes a trigger pulse generating circuit 31 and a magnetic latching relay switching circuit 32. The trigger pulse generating circuit 31 can adopt various circuits capable of generating trigger electrical pulses. The trigger pulse generating circuit 31 is connected to the first input power module through a trigger element, such as a relay, a photoelectric coupling device or a coupling transformer. When the power supply state of the first input power module 1 changes, such as power interruption or power restoration, the trigger pulse generating circuit 31 can generate a trigger electrical pulse to trigger the magnetic latching relay switching circuit 32 to generate a switching action, and switch the output power module 4 to be connected to the first input power module 1, or to the second input power module 2.

[0039] Specifically, when the first input power module 1 loses power, that is, the power supply voltage on the first input power module 1 drops significantly and the power supply of normal voltage cannot be guaranteed, the trigger pulse generating circuit 31 generates a positive trigger electric pulse, controls the trigger magnetic latching relay switching circuit 32 to quickly switch the output power module 4 to connect with the second input power module 2, and uses the second DC power supply to provide power to the output power module 4; when the first input power module 1 resumes normal power supply, the trigger pulse generating circuit 31 generates a negative trigger electric pulse, triggers the magnetic latching relay switching circuit 32 to quickly switch the output power module 4 to connect with the first input power module 1, and uses the first DC power supply to provide power to the output power module 4. That is, as long as the power supply to the first input power module 1 is normal, the output power module 4 uses the first DC power supply to provide power.

[0040] The magnetic latching relay switching circuit 32 uses a magnetic latching relay to switch the connection circuit. The magnetic latching relay can not only provide a higher contact current, but also switch the connection state under the action of a pulse current. The magnetic latching relay coil does not need to be supplied with current for a long time, so that the power-on time of the magnetic latching relay coil is shorter, the current load is smaller, the aging speed during the working process is slower, the reliability is higher, and the service life is longer.

[0041] In some embodiments of the DC dual power switching device of the present application, as Figure 2 As shown, the first input power module 1 includes a first input power circuit 11, a first trigger relay circuit 12 and a first input power indication circuit 13. The first input power circuit 11 is connected to the first DC power supply for providing and transmitting DC power.

[0042] The first trigger relay circuit 12 is connected to the first input power circuit 11, and works by using the DC power transmitted by the first input power circuit 11. The first trigger relay circuit 12 is provided with a first trigger relay 121, which can be operated under the action of the power on the first input power circuit 11, change the connection state of the contacts of the first trigger relay 121, and generate a trigger pulse to control the action of the trigger pulse generating circuit 31.

[0043] The first input power indication circuit 13 can use various electronic circuits that can indicate whether there is current supply in the circuit. The first input power indication circuit 13 is connected to the first input power circuit 11 and is used to indicate the power status of the first input power circuit 11, so that the staff can understand the power supply status of the first input power circuit 11.

[0044] The second input power module 2 includes a second input power circuit 21, a second trigger relay circuit 22 and a second input power indication circuit 23. The second input power circuit 21 is connected to a second DC power source for providing and transmitting DC power.

[0045] The second trigger relay circuit 22 is connected to the second input power circuit 21 and works by using the DC power transmitted by the second input power circuit 21. The second trigger relay circuit 22 is provided with a second trigger relay 221, which can be operated under the action of the power on the second input power circuit 21, change the connection state of the contacts of the second trigger relay 221, and generate an electrical signal representing the change of the power state on the second input power circuit 21.

[0046] The second input power indication circuit 23 can use various electronic circuits that can indicate whether there is current supply in the circuit. The second input power indication circuit 23 is connected to the second input power circuit 21 and is used to indicate the power status of the second input power circuit 21, so that the staff can understand the power supply status of the second input power circuit 21.

[0047] In a preferred embodiment of the DC dual power switching device of the present application, as Figure 2 As shown, the first trigger relay circuit 12 and the first input power indication circuit 13 are connected in series to the first input power circuit 11. In this way, the indication signal of the first input power indication circuit 13 not only reflects the power supply condition of the first input power circuit 11, but also includes the working condition of the first trigger relay circuit 12.

[0048] Similarly, the second trigger relay circuit 22 and the second input power indication circuit 23 are connected in series to the second input power circuit 21, so that the indication signal of the second input power indication circuit 23 not only reflects the power supply condition on the second input power circuit 21, but also includes the working condition of the second trigger relay circuit 22.

[0049] As a specific implementation of the DC dual power switching device of the present application, Figure 2 As shown, the first trigger relay circuit 12 includes a diode D11, a trigger relay coil RLA2, a resistor RD1 and a diode D12, wherein the trigger relay coil RLA2 is a working coil of the first trigger relay 121. The anode of the diode D11 is connected to the anode line +KM1 of the first input power circuit 11, the cathode of the diode D11 is connected to one end of the trigger relay coil RLA2, and the other end of the trigger relay coil RLA2 is connected to the first input power indication circuit 13. After the resistor RD1 and the diode D12 are connected in series, they are connected in parallel to the two ends of the trigger relay coil RLA2, and the cathode of the diode D12 is connected to the connection circuit where the trigger relay coil RLA2 is connected to the cathode of the diode D11.

[0050] The first input power indication circuit 13 includes a light-emitting diode H1, a resistor RH1 and a resistor R11. The positive electrode of the light-emitting diode H1 is connected to the trigger relay coil RLA2. One end of the resistor R11 is connected to the negative electrode of the light-emitting diode H1, and the other end is connected to the negative electrode line -KM1 of the first input power circuit 11. The resistor RH1 is connected in parallel to both ends of the light-emitting diode H1.

[0051] When the power supply of the first DC power supply is normal and is transmitted normally on the first input power supply circuit 11, the current on the positive line +KM1 of the first input power supply circuit 11 flows through the diode D11, the trigger relay coil RLA2, the resistor RH1 and the light-emitting diode H1, and the resistor R11 into the negative line -KM1 of the first input power supply circuit 11, and the first trigger relay 121 is attracted by the current, and the light-emitting diode H1 emits light due to the current passing through it, indicating that the power supply on the first input power supply circuit 11 is normal and the first trigger relay 121 is working normally.

[0052] Once the first input power circuit 11 loses power, the current in the trigger relay coil RLA2 disappears, and the first trigger relay 121 releases and generates a power failure trigger signal; at the same time, the light-emitting diode H1 stops emitting light, indicating that the first input power circuit 11 is powered abnormally, or the diode D11 and the trigger relay coil RLA2 are open. The resistor RD1 and the diode D12 can quickly release the induced electromotive force generated in the trigger relay coil RLA2 when the first input power circuit 11 loses power, thereby improving the response time of the first trigger relay 121. The resistor RH1 and the emitter resistor R11 can control the voltage across the light-emitting diode H1 and the current flowing through the light-emitting diode H1, thereby controlling the brightness of the light-emitting diode H1. The resistor RH1 can also provide a current path for the trigger relay coil RLA2 when the light-emitting diode H1 is open, thereby preventing the light-emitting diode H1 from being damaged and causing the first trigger relay 121 to fail to work normally, thereby improving the reliability of the operation of the dual power switching device.

[0053] The second trigger relay circuit 22 includes a diode D21, a trigger relay coil RLA3, a resistor RD2 and a diode D22, wherein the trigger relay coil RLA3 is a working coil of the second trigger relay 221. The anode of the diode D21 is connected to the anode line +KM2 of the second input power circuit 21, the cathode of the diode D21 is connected to one end of the trigger relay coil RLA3, and the other end of the trigger relay coil RLA3 is connected to the second input power indication circuit 23. After the resistor RD2 is connected in series with the diode D22, it is connected in parallel to both ends of the trigger relay coil RLA3, and the cathode of the diode D22 is connected to the connection circuit where the trigger relay coil RLA3 is connected to the cathode of the diode D21.

[0054] The second input power indication circuit 23 includes a light-emitting diode H2, a resistor RH2 and a resistor R21. The positive electrode of the light-emitting diode H2 is connected to the trigger relay coil RLA3. One end of the resistor R21 is connected to the negative electrode of the light-emitting diode H2, and the other end is connected to the negative electrode line -KM2 of the second input power circuit 21. The resistor RH2 is connected in parallel to both ends of the light-emitting diode H2.

[0055] When the power supply of the second DC power supply is normal and is transmitted normally on the second input power supply circuit 21, the current on the positive line +KM2 of the second input power supply circuit 21 flows through the diode D21, the trigger relay coil RLA3, the resistor RH2 and the light-emitting diode H2, and the resistor R21 into the negative line -KM2 of the second input power supply circuit 21, and the second trigger relay 221 is attracted by the current, and the light-emitting diode H2 emits light due to the current passing through it, indicating that the power supply on the second input power supply circuit 21 is normal and the second trigger relay 221 is working normally.

[0056] Once the second input power circuit 21 loses power, the current in the trigger relay coil RLA3 disappears, and the second trigger relay 221 releases and generates a power failure trigger signal; at the same time, the light-emitting diode H2 stops emitting light, indicating that the second input power circuit 21 has an abnormal power supply, or the diode D21 and the trigger relay coil RLA3 are open. The resistor RD2 and the diode D22 can quickly release the induced electromotive force generated in the trigger relay coil RLA3 when the second input power circuit 21 loses power, thereby improving the response time of the second trigger relay 221. The resistor RH2 and the emitting resistor R21 can control the voltage across the light-emitting diode H2 and the current flowing through the light-emitting diode H2, thereby controlling the luminous brightness of the light-emitting diode H2. The resistor RH2 can also provide a current path for the trigger relay coil RLA3 when the light-emitting diode H2 is open, thereby preventing the light-emitting diode H2 from being damaged and causing the second trigger relay 221 to fail to work normally, thereby improving the reliability of the operation of the dual power switching device.

[0057] In some embodiments of the DC dual power switching device of the present application, as Figure 2 As shown, the trigger pulse generating circuit 31 includes a diode D13, a trigger relay contact group RL2B, a capacitor C1, a resistor R1 and a resistor R3. The trigger relay contact group RL2B is a contact group of the first trigger relay 121, and the trigger relay contact group RL2B includes a moving contact K1, a normally closed static contact K2 and a normally open static contact K3. The positive electrode of the diode D13 is connected to the positive line +KM1 of the first input power circuit 11, and the negative electrode is connected to the normally open static contact K3. The capacitor C1 adopts an electrolytic capacitor with relatively small leakage current, such as a tantalum electrolytic capacitor. The positive electrode of the capacitor C1 is connected to the moving contact K1, and the negative electrode is connected to one end of the resistor R1; the other end of the resistor R1 is connected to the magnetic latching relay switching circuit 32. The resistor R3 is connected between the normally closed static contact K2 and the negative line -KM1 of the first input power circuit 11. The setting of R3 can also prevent the moving contact K1 from generating an instantaneous short circuit when switching between the normally closed static contact K2 and the normally open static contact K3. Therefore, R3 needs to use a resistor with higher power, usually a wirewound resistor.

[0058] When the first DC power supply is normally supplied by the first input power circuit 11, the first trigger relay 121 is energized, the moving contact K1 of the trigger relay contact group RL2B is disconnected from the normally closed contact K2 and connected to the normally open contact K3, and the current on the first input power circuit 11 charges the capacitor C1 through the diode D13, the resistor R1 and the magnetic latching relay switching circuit 32, generating a positive triggering electrical pulse that triggers the magnetic latching relay switching circuit 32 to operate; and when the first input power circuit 11 loses power, the first trigger relay 121 is released, the moving contact K1 of the trigger relay contact group RL2B is disconnected from the normally open contact K3 and contacts the normally closed contact, and the charge on the capacitor C1 is discharged through the resistor R3, the magnetic latching relay switching circuit 32 and the resistor R1, generating a negative triggering electrical pulse that triggers the magnetic latching relay switching circuit 32 to operate in the reverse direction.

[0059] In a preferred embodiment of the DC dual power switching device of the present application, as Figure 2 As shown, the magnetic holding relay switching circuit 32 includes a magnetic holding relay coil RL1A, a resistor R2, a normally closed contact group RL1B, a normally open contact group RL1C, a normally closed contact group RL1D and a normally open contact group RL1E, wherein the magnetic holding relay coil RL1A is the working coil of the magnetic holding relay, and the normally closed contact group RL1B, the normally open contact group RL1C, the normally closed contact group RL1D and the normally open contact group RL1E are respectively different contact groups on the magnetic holding relay.

[0060] The positive terminal of the magnetic latching relay coil RL1A is connected to the resistor R1, and the negative terminal is connected to the negative line -KM1 of the first input power circuit 11; the resistor R2 is connected in parallel to both ends of the magnetic latching relay coil RL1A. The normally closed contact group RL1B is connected between the positive line +KM2 of the second input power circuit 21 and the positive line +KM of the output power module 4, the normally open contact group RL1C is connected between the positive line +KM1 of the first input power circuit 11 and the positive line +KM of the output power module 4, the normally closed contact group RL1D is connected between the negative line -KM2 of the second input power circuit 21 and the negative line -KM of the output power module 4, and the normally open contact group RL1E is connected between the negative line -KM1 of the first input power circuit 11 and the negative line -KM of the output power module 4.

[0061] When the first trigger relay 121 is energized, the power of the first input power circuit 11 charges the capacitor C1 through the parallel circuit of the diode D13, the resistor R1, the resistor R2 and the magnetic latching relay coil RL1A, and forms a circuit at both ends of the magnetic latching relay coil RL1A. Figure 3 A positive triggering electrical pulse is shown.

[0062] The internal resistance of the magnetic latching relay coil RL1A is defined as RL. The rated voltage of the first DC power supply is Un. When the capacitor C1 is charged, the voltage formed across the magnetic latching relay coil RL1A is The initial value of is: Usually, the magnetic latching relay coil RL1A needs to work under a pulse voltage of 6 times the rated voltage, and the pulse voltage needs to be kept above the rated voltage for at least 8ms to operate reliably. Therefore, a magnetic latching relay with a rated voltage of 24VDC is selected to control the voltage during initial charging. The value is 144VDC, and the duration of the generated trigger pulse voltage above 24VDC is 15ms. Based on this standard, the parameters of capacitor C1, resistor R1, resistor R2 and magnetic latching relay coil RL1A are calculated and selected.

[0063] Select the magnetic latching relay coil RL1A with an internal resistance of 144Ω, and select C1 = 47uF, R1 = 620Ω, R2 = 6.2K. In this state, the charging pulse waveform of capacitor C1 is as follows Figure 3 As shown, the voltage across the coil RL1A of the magnetic latching relay is maintained above 24.4V for 16.6ms. During the charging process of the capacitor C1, the magnetic latching relay operates reliably under the triggering of the positive charging pulse, the normally open contact group RL1C and the normally open contact group RL1E are energized, and the normally closed contact group RL1B and the normally closed contact group RL1D are disconnected, and the positive line +KM of the output power module 4 is connected to the positive line +KM1 of the first input power circuit 11, and disconnected from the positive line +KM2 of the second input power circuit 21; at the same time, the negative line -KM of the output power module 4 is connected to the negative line -KM1 of the first input power circuit 11, and disconnected from the negative line -KM2 of the second input power circuit 21, and the first DC power supply is supplied through the output power module 4.

[0064] In order to distinguish in the waveform whether the output power module 4 is powered by the first DC power supply or the second DC power supply, the voltage of the first DC power supply is adjusted to 220VDC, and the voltage of the second DC power supply is adjusted to 150VDC. The waveform of the output power module 4 when it is switched from the second DC power supply to the first DC power supply is as follows: Figure 5 As shown in the waveform, it can be seen that the switching time from the second DC power supply to the first DC power supply is 5.01ms, which is far lower than the requirement of the power industry that the switching time should not exceed 20ms. After the switching is completed, the first DC power supply provides stable power supply.

[0065] During the continuous power supply of the first input power circuit 11, when the capacitor C1 is fully charged, no current flows through the circuit where the capacitor C1 is located, and no current flows through the magnetic latching relay coil RL1A, and the magnetic latching relay also maintains its original state.

[0066] When the first input power circuit 11 loses power, the first trigger relay 121 is released, the moving contact K1 contacts the normally closed contact, and the charge on the capacitor C1 is discharged through the resistor R3, the parallel circuit of the magnetic latching relay coil RL1A and the resistor R2, and the resistor R1.

[0067] When C1=47uF, R1=620Ω, R2=6.2K, and the internal resistance of the magnetic latching relay coil RL1A is 144Ω, the capacitor C1 discharges at both ends of the magnetic latching relay coil RL1A to form the following Figure 4 The negative triggering electric pulse shown in the figure, wherein the voltage across the coil RL1A of the magnetic latching relay is maintained above 23.0V for 15.1ms. During the discharge process of the capacitor C1, the magnetic latching relay operates reliably under the triggering of the negative discharge pulse, the normally closed contact group RL1B and the normally closed contact group RL1D are closed, the normally open contact group RL1C and the normally open contact group RL1E are disconnected, the positive line +KM of the output power module 4 is connected to the positive line +KM2 of the second input power circuit 21, and is disconnected from the positive line +KM1 of the first input power circuit 11; at the same time, the negative line -KM of the output power module 4 is connected to the negative line -KM2 of the second input power circuit 21, and is disconnected from the negative line -KM1 of the first input power circuit 11, and the second DC power supply is supplied through the output power module 4.

[0068] The waveform of the output power module 4 when it switches from the first DC power supply to the second DC power supply is as follows: Figure 6 As shown in the waveform, it can be seen that the switching time from the first DC power supply to the second DC power supply is 15.8ms, which is also lower than the power industry's requirement of no more than 20ms. After the switching is completed, the second DC power supply provides stable power supply.

[0069] During the continuous power supply of the second input power circuit 21 , when the capacitor C1 is discharged, no current flows through the circuit where the capacitor C1 is located, and no current flows through the coil RL1A of the magnetic latching relay, and the magnetic latching relay also maintains its original state.

[0070] If the first DC power source is restored and the power of the first input power circuit 11 returns to normal, the first trigger relay 121 is energized to restart the charging process of the capacitor C1.

[0071] In some embodiments of the DC dual power switching device of the present application, as Figure 2As shown, a diode D23 is provided on the connection line connecting the positive line +KM of the output power module 4 and the positive line +KM2 of the second input power module 2. Specifically, the cathode of the diode D23 is connected to the positive line +KM of the output power module 4, and the cathode of the diode D23 is connected to the normally closed contact group RL1B. A diode D14 is provided on the connection line connecting the positive line +KM of the output power module 4 and the positive line +KM1 of the first input power module 1, and the cathode of the diode D14 is connected to the positive line +KM of the output power module 4, and the anode of the diode D14 is connected to the normally open contact group RL1C.

[0072] A diode D24 is provided on the connection line connecting the negative line -KM of the output power module 4 and the negative line -KM2 of the second input power module 2, the anode of the diode D24 is connected to the negative line -KM of the output power module 4, and the cathode of the diode D24 is connected to the normally closed contact group RL1D. A diode D15 is provided on the connection line connecting the negative line -KM of the output power module 4 and the negative line -KM1 of the first input power module 1, the anode of the diode D15 is connected to the negative line -KM of the output power module 4, and the cathode of the diode D15 is connected to the normally open contact group RL1E.

[0073] Diode D14, diode D15, diode D23 and diode D24 can prevent the first input power circuit 11 or the second input power circuit 21 from being short-circuited due to the reverse polarity of the power supply. When selecting diode D14, diode D15, diode D23 and diode D24, the power consumption of the diode should be considered to prevent the current flowing through the diode from being too large when the back-end load of the power supply is too large, thereby causing damage to the diode.

[0074] In a preferred embodiment of the DC dual power switching device of the present application, as Figure 2 As shown, the output power module 4 includes a first power supply indication circuit 41 and a second power supply indication circuit 42. The first power supply indication circuit 41 includes a resistor R12, a resistor RH3 and a light emitting diode H3, one end of the resistor R12 is connected to the positive electrode of the diode D14, specifically connected between the positive electrode of the diode D14 and the normally open contact group RL1C; the other end of the resistor R12 is connected to the positive electrode of the light emitting diode H3, the negative electrode of the light emitting diode H3 is connected to the negative electrode of the diode D15, specifically connected between the negative electrode of the axis diode D15 and the normally open contact group RL1E; the resistor RH3 is connected in parallel to both ends of the light emitting diode H3.

[0075] The second power supply indication circuit 42 includes a resistor R22, a resistor RH4 and a light-emitting diode H4. One end of the resistor R22 is connected to the positive electrode of the diode D23, specifically connected between the positive electrode of the diode D23 and the normally closed contact group RL1B; the other end of the resistor R22 is connected to the positive electrode of the light-emitting diode H4, and the negative electrode of the light-emitting diode H4 is connected to the negative electrode of the diode D24, specifically connected between the negative electrode of the diode D24 and the normally closed contact group RL1D; the resistor RH4 is connected in parallel to both ends of the light-emitting diode H4.

[0076] When the normally open contact group RL1C and the normally open contact group RL1E are closed, and the first DC power supply supplies power to the output power module 4, the current flows through the light emitting diode H3 through the resistor R12, and the light emitting diode H3 emits light, indicating that the first DC power supply is currently being used for power supply. The voltage at both ends of the light emitting diode H3 and the current flowing through the light emitting diode H3 can be controlled by the resistor R12 and the resistor RH3, thereby controlling the brightness of the light emitting diode H3. When the normally closed contact group RL1B and the normally closed contact group RL1D are closed, and the second DC power supply supplies power to the output power module 4, the current flows through the light emitting diode H4 through the resistor R22, and the light emitting diode H4 emits light, indicating that the second DC power supply is currently being used for power supply. The voltage at both ends of the light emitting diode H4 and the current flowing through the light emitting diode H4 can be controlled by the resistor R22 and the resistor RH4, thereby controlling the brightness of the light emitting diode H4.

[0077] In some embodiments of the DC dual power switching device of the present application, as Figure 2 As shown, a diode protection circuit 43 is also provided in the output power module 4. The diode protection circuit 43 is a diode bridge BR5 formed by connecting four diodes, the input end of the diode bridge BR5 is connected to the negative line -KM of the output power module 4, and the output end of the diode bridge BR5 is connected to the positive line +KM of the output power module 4.

[0078] The diode bridge BR5 can prevent voltage spikes and current mutations from damaging the circuit. Specifically, when the relay coil is de-energized, a reverse electromotive force will be generated in the coil due to the inductance of the coil. This reverse electromotive force will cause the voltage in the circuit to rise instantly, and may even damage other electronic components in the circuit. The diode bridge BR5 can provide a discharge path for the reverse electromotive force, effectively reducing the instantaneous voltage rise caused by the reverse electromotive force, thereby avoiding the generation of voltage spikes.

[0079] In some embodiments of the DC dual power switching device of the present application, as Figure 1 and Figure 2As shown, the DC dual power switching device of the present application is also provided with an alarm trigger module 5. The alarm trigger module 5 includes a first alarm contact group RL2C and a second alarm contact group RL3B, wherein the first alarm contact group RL2C is a group of normally closed contacts on the first trigger relay 121. When the first input power circuit 11 loses power, the first trigger relay 121 is released, the first alarm contact group RL2C is closed, and the first alarm signal contact GJ1 of the alarm trigger module 5 is connected to the signal contact GJCOM. The first alarm signal contact GJ1 sends an alarm signal of the first input power circuit 11 losing power to the background, so that the background system can perform corresponding processing. The second alarm contact group RL3 is a group of normally closed contacts on the second trigger relay 221. When the second input power circuit 21 loses power, the second trigger relay 221 is released, the second alarm contact group RL3B is closed, and the second alarm signal contact GJ2 of the alarm trigger module 5 is connected to the signal contact GJCOM. The second alarm signal contact GJ2 sends an alarm signal of power loss in the second input power circuit 21 to the background for the background system to perform corresponding processing.

[0080] The setting of the alarm trigger module 5 can send out a corresponding power failure alarm signal when the first input power circuit 11 or the second input power circuit 21 loses power, and provides the background application system with a power failure processing trigger signal of the corresponding circuit, which helps to enrich the processing means of the background application system when the first input power circuit 11 or the second input power circuit 21 loses power.

[0081] In the description of the present invention, the description with reference to the terms "one embodiment", "specific embodiment", "preferred embodiment" and the like means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In the present invention, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0082] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A DC dual power supply switching device, characterized in that: The invention comprises a first input power module (1), a second input power module (2), a power supply switching module (3) and an output power module (4); the power supply switching module (3) is connected between the first input power module (1), the second input power module (2) and the output power module (4); the power supply switching module (3) comprises a trigger pulse generating circuit (31) and a magnetic latching relay switching circuit (32); the trigger pulse generating circuit (31) can trigger the magnetic latching relay switching circuit (32) according to the power supply state of the first input power module (1), so that the output power module (4) is connected to the first input power module (1) or to the second input power module (2).

2. The DC dual power switching device according to claim 1, characterized in that: The first input power module (1) comprises a first input power circuit (11), a first trigger relay circuit (12) and a first input power indication circuit (13); the first input power circuit (11) is connected to a first DC power supply; the first trigger relay circuit (12) and the first input power indication circuit (13) are connected to the first input power circuit (11); the first trigger relay circuit (12) comprises a first trigger relay (121); the first trigger relay (121) can change its working state according to the power supply state of the first input power circuit (11), so that the trigger pulse generating circuit (31) generates a trigger pulse; the first input power indication circuit (13) can indicate that the first input power circuit (11) is powered on. The second input power module (2) comprises a second input power circuit (21), a second trigger relay circuit (22) and a second input power indication circuit (23); the second input power circuit (21) is connected to a second DC power supply; the second trigger relay circuit (22) and the second input power indication circuit (23) are connected to the second input power circuit (21); the second trigger relay circuit (22) comprises a second trigger relay (221); the second trigger relay (221) can change its working state according to the power supply state of the second input power circuit (21); and the second input power indication circuit (23) can indicate the power supply state of the second input power circuit (21).

3. The DC dual power switching device according to claim 2, characterized in that: The first trigger relay circuit (12) and the first input power indication circuit (13) are connected in series to each other and are then connected to the first input power circuit (11); the second trigger relay circuit (22) and the second input power indication circuit (23) are connected in series to each other and are then connected to the second input power circuit (21).

4. The DC dual power switching device according to claim 3, characterized in that: The first trigger relay circuit (12) comprises a diode D11, a trigger relay coil RLA2, a resistor RD1 and a diode D12, wherein the anode of the diode D11 is connected to the anode of the first input power circuit (11), the cathode of the diode D11 is connected to the trigger relay coil RLA2, the trigger relay coil RLA2 is connected to the first input power indication circuit (13), the resistor RD1 is connected in series with the diode D12 and then connected in parallel with the trigger relay coil RLA2, and the cathode of the diode D12 is connected to the cathode of the diode D11; the first input power indication circuit (13) comprises a light emitting diode H1, a resistor RH1 and a resistor R11, the anode of the light emitting diode H1 is connected to the trigger relay coil RLA2, the resistor R11 is connected between the cathode of the light emitting diode H1 and the cathode of the first input power circuit (11), and the resistor RH1 is connected in parallel with the light emitting diode H1; The second trigger relay circuit (22) comprises a diode D21, a trigger relay coil RLA3, a resistor RD2 and a diode D22, wherein the anode of the diode D21 is connected to the anode of the second input power circuit (21), the cathode of the diode D21 is connected to the trigger relay coil RLA3, the trigger relay coil RLA3 is connected to the second input power indication circuit (23), the resistor RD2 is connected in series with the diode D22 and then connected in parallel with the trigger relay coil RLA3, and the cathode of the diode D22 is connected to the cathode of the diode D21; the second input power indication circuit (23) comprises a light emitting diode H2, a resistor RH2 and a resistor R21, the anode of the light emitting diode H2 is connected to the trigger relay coil RLA3, the resistor R21 is connected between the cathode of the light emitting diode H2 and the cathode of the second input power circuit (21), and the resistor RH2 is connected in parallel with the light emitting diode H2.

5. The DC dual power switching device according to claim 2, characterized in that: The trigger pulse generating circuit (31) comprises a diode D13, a trigger relay contact group RL2B, a capacitor C1, a resistor R1 and a resistor R3; the trigger relay contact group RL2B comprises a moving contact K1, a normally closed static contact K2 and a normally open static contact K3; the diode D13 is connected between the positive electrode of the first input power circuit (11) and the normally open static contact K3; one end of the capacitor C1 is connected to the moving contact K1 and the other end is connected to the resistor R1; the other end of the resistor R1 is connected to the magnetic latching relay switching circuit (32); the resistor R3 is connected between the normally closed static contact K2 and the negative electrode of the first input power circuit (11); and the trigger relay contact group RL2B can change the connection state according to the action of the first trigger relay (121).

6. The DC dual power switching device according to claim 5, characterized in that: The magnetic latching relay switching circuit (32) comprises a magnetic latching relay coil RL1A, a resistor R2, a normally closed contact group RL1B, a normally open contact group RL1C, a normally closed contact group RL1D and a normally open contact group RL1E, the magnetic latching relay coil RL1A is connected between the resistor R1 and the negative electrode of the first input power circuit (11), the resistor R2 is connected in parallel with the magnetic latching relay coil RL1A, the normally closed contact group RL1B is connected between the positive electrode of the second input power circuit (21) and the positive electrode of the output power module (4), and the normally open contact group RL1C is connected between the positive electrode of the second input power circuit (21) and the positive electrode of the output power module (4). The normally closed contact group RL1D is connected between the positive electrode of the first input power circuit (11) and the positive electrode of the output power module (4), the normally open contact group RL1E is connected between the negative electrode of the first input power circuit (11) and the negative electrode of the output power module (4), and the normally closed contact group RL1B, the normally open contact group RL1C, the normally closed contact group RL1D and the normally open contact group RL1E are capable of changing the open and closed states under the action of a trigger pulse in the magnetic latching relay coil RL1A.

7. The DC dual power switching device according to claim 1, characterized in that: A diode D23 is provided on the connection line connecting the positive electrode of the output power module (4) and the second input power module (2), a diode D14 is provided on the connection line connecting the positive electrode of the output power module (4) and the first input power module (1), a diode D24 is provided on the connection line connecting the negative electrode of the output power module (4) and the second input power module (2), and a diode D15 is provided on the connection line connecting the negative electrode of the output power module (4) and the first input power module (1).

8. The DC dual power switching device according to claim 7, characterized in that: The output power module (4) comprises a first power supply indication circuit (41) and a second power supply indication circuit (42), wherein the first power supply indication circuit (41) comprises a resistor R12, a resistor RH3 and a light emitting diode H3, wherein one end of the resistor R12 is connected to the positive electrode of the diode D14, and the other end is connected to the light emitting diode H3, the other end of the light emitting diode H3 is connected to the negative electrode of the diode D15, and the resistor RH3 is connected in parallel with the light emitting diode H3; the second power supply indication circuit (42) comprises a resistor R22, a resistor RH4 and a light emitting diode H4, wherein one end of the resistor R22 is connected to the positive electrode of the diode D23, and the other end is connected to the light emitting diode H4, the other end of the light emitting diode H4 is connected to the negative electrode of the diode D24, and the resistor RH4 is connected in parallel with the light emitting diode H4.

9. The DC dual power switching device according to claim 7, characterized in that: The output power module (4) further comprises a diode protection circuit (43), wherein the diode protection circuit (43) comprises a diode bridge BR5, wherein the diode bridge BR5 is connected between the positive electrode and the negative electrode of the output power module (4).

10. The DC dual power switching device according to any one of claims 1 to 9, characterized in that: It also comprises an alarm triggering module (5), wherein the alarm triggering module (5) can generate an alarm signal when the first input power module (1) or the second input power module (2) loses power.

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