Dual-power supply circuit and power supply system

Abstract

The invention relates to a dual-power supply circuit and a power supply system, and belongs to the technical field of power supply switching of power supply systems. The dual-power-supply power supply circuit comprises two power input ends, a power output end used for being connected with a load and a first intermediate relay. The cathodes of the two power input ends are connected together and then are connected with the cathode of the power output end through a first cathode connecting wire; the anode of the first power input end is connected in series with a normally open contact of the first intermediate relay and then connected with the anode of the power output end; the anode of the first power input end is connected in series with a coil of a first intermediate relay and then connected with a first cathode connecting wire; the anode of the second power input end is connected in series with the normally-closed contact of the first intermediate relay and then connected with the anode of the power output end. According to the invention, the first power input end can be automatically switched to the second power input end when the first power input end fails according to the power-on and power-off conditions of the coil of the first intermediate relay, so that the cost is low, and the reliability is high.

Description

Technical Field

[0001] The invention relates to a dual-power supply circuit and a power supply system, belonging to the technical field of power supply switching of power supply systems. Background Art

[0002] In the power supply system, the controller unit or other low-voltage DC loads require a stable supply voltage, which is generally derived from a power converter.

[0003] In a power supply system, the power supply circuit from a power converter to a power load is generally a single loop, that is, only the power converter is working in the loop. Once the power converter fails, it will cause the power load at the back end to work unstably, and in severe cases, it will cause the entire power supply system to be paralyzed. Therefore, this power supply loop has the problem of low reliability.

[0004] In order to solve the problem of low reliability of the power supply circuit in the power supply system, there are two commonly used solutions in the industry: one is to use a more reliable power converter as a replacement, and the other is to use two power converters of the same specification and a redundant module to combine to achieve parallel connection of the two power converters. Both methods can improve the overall reliability of the power supply circuit.

[0005] However, both solutions adopted by the industry have some disadvantages. If a more reliable power converter is used as an alternative, the price cost will increase by more than an order of magnitude, as the more reliable power converter may reach military grade or above, which is a high cost problem. In the solution of using two power converters of the same specification and a redundant module to implement two power converters, the core components inside the redundant module are semiconductor power devices such as diodes or metal-oxide-semiconductor field-effect transistors (MOSFET), which are easy to heat up when working, resulting in instability. Once the heat dissipation is not in place, extreme damage such as burning of the tube will occur. Therefore, the overall reliability of the combined solution will not be significantly improved.

[0006] The Chinese invention patent application with application publication number CN118677089A discloses a dual power switching device, a switching method, a circuit board and an electronic device. The dual power switching device includes: a first power supply circuit, a second power supply circuit, a microprocessor, a detection circuit and a switching module, wherein the output end of the first power supply circuit is connected to the detection circuit, the output end of the detection circuit is connected to the microprocessor, the switching module is used to disconnect the path between the first power supply circuit and the power load when the first power supply circuit fails, and to conduct the path between the second power supply circuit and the power load, the detection circuit is used to detect the output voltages of the first power supply circuit and the second power supply circuit, the second power supply circuit is used to supply power to the power load when the path between the second power supply circuit and the power load is conducted, and the microprocessor is used to output a regulation signal to the switching module according to the output signal of the detection circuit.

[0007] The solution with application publication number CN118677089A improves the reliability of the power supply circuit by adding a power supply circuit as a redundant device. Compared with using military-grade products in the power conversion module of a single power supply circuit, the cost is lower; and because the switching module uses two relays and a capacitor, the reliability is higher compared with the solution using semiconductor power devices as the switching device. However, this solution still has the problem of high cost because it requires a special detection circuit to detect the working status of the first power supply circuit and the second power supply circuit, and requires a special microprocessor to control the switching module to switch according to the detection results. Summary of the invention

[0008] The object of the present invention is to provide a dual power supply circuit and a power supply system to solve the problem of high cost in the prior art, so as to improve the reliability of the power supply circuit at a lower cost.

[0009] To achieve the above object, the solution of the present invention includes: A dual power supply circuit of the present invention includes the following circuit scheme: Circuit scheme 1 includes two power input terminals, a power output terminal for connecting a load, and a first intermediate relay; The negative electrodes of the two power input terminals are connected together and then connected to the negative electrode of the power output terminal through a first negative electrode connecting line; The positive electrode of the first power input terminal is connected in series with the normally open contact of the first intermediate relay, and then connected to the positive electrode of the power output terminal; the positive electrode of the first power input terminal is also connected in series with the coil of the first intermediate relay and then connected to the first negative electrode connection line; The positive electrode of the second power input terminal is connected in series with the normally closed contact of the first intermediate relay, and then connected to the positive electrode of the power output terminal.

[0010] Circuit scheme 2, based on circuit scheme 1, after the output end of the normally open contact of the first intermediate relay and the output end of the normally closed contact of the first intermediate relay are connected, they are connected to the positive pole of the power output end through the first positive pole connecting line.

[0011] Circuit scheme three, based on circuit scheme one, the first intermediate relay includes a first single-pole double-throw switch; The normally open end of the first single-pole double-throw switch is connected to the positive electrode of the first power input terminal, the normally closed end is connected to the positive electrode of the second power input terminal, and the common end is connected to the positive electrode of the power output terminal through the first positive electrode connecting line; The normally open end and the common end of the first single-pole double-throw switch constitute the normally open contact of the first intermediate relay, and the normally closed end and the common end of the first single-pole double-throw switch constitute the normally closed contact of the first intermediate relay.

[0012] Circuit scheme 4, based on circuit scheme 3, further includes a diode whose cathodes are connected together and then connected to the common end of the first single-pole double-throw switch; The anode of the first diode is connected to the normally open terminal of the first single-pole double-throw switch; The anode of the second diode is connected to the normally closed terminal of the first single-pole double-throw switch.

[0013] Circuit scheme 5, based on circuit scheme 1, further includes a first indicator light; The positive electrode of the first indicator light is connected to the positive electrode of the first power input terminal; The cathode of the first indicator light is connected to the cathode of the first power input terminal.

[0014] Circuit scheme six, based on circuit scheme five, further comprising a first relay; The coil of the first relay is connected in parallel to the two ends of the first indicator light; the normally open contact of the first relay is used to be connected in parallel with the signal acquisition device in the background system.

[0015] Circuit scheme seven, based on circuit scheme one, also includes a second indicator light; The positive electrode of the second indicator light is connected to the positive electrode of the second power input terminal; The cathode of the second indicator light is connected to the cathode of the second power input terminal.

[0016] Circuit scheme eight, based on circuit scheme seven, further comprising a second relay; The coil of the second relay is connected in parallel to the two ends of the second indicator light; the normally open contact of the second relay is used to be connected in parallel with the signal acquisition device in the background system.

[0017] Circuit solution nine, based on circuit solution two or circuit solution three, further includes a third indicator light; The positive electrode of the third indicator light is connected to the first positive electrode connecting wire; The cathode of the third indicator light is connected to the first cathode connecting wire.

[0018] Circuit scheme 10 is based on circuit scheme 9 and further includes a third relay; The coil of the third relay is connected in parallel to the two ends of the third indicator light; the normally open contact of the third relay is used to be connected in parallel with the signal acquisition device in the background system.

[0019] Circuit solution 11, based on circuit solution 2 or circuit solution 3, further includes a second intermediate relay; The normally closed contact of the second intermediate relay is connected in series to the first positive connecting line.

[0020] Circuit solution 12, based on circuit solution 11, the second intermediate relay includes a second single-pole double-throw switch; The normally open end of the second single-pole double-throw switch is left floating; The normally closed end of the second single-pole double-throw switch is connected to the common end of the first single-pole double-throw switch; The normally open end of the second single-pole double-throw switch and the common end of the second single-pole double-throw switch constitute a normally open contact of the second intermediate relay; The normally closed end of the second single-pole double-throw switch and the common end of the second single-pole double-throw switch constitute a normally closed contact of the second intermediate relay.

[0021] Circuit solution 13 is based on circuit solution 12 and further includes a third diode; The anode of the third diode is connected to the normally closed end of the second single-pole double-throw switch; The cathode of the third diode is connected to the common terminal of the second single-pole double-throw switch.

[0022] Circuit solution 14, based on circuit solution 1, further includes a first power converter and a second power converter; The first power input terminal is connected to the input power through a first power converter; The second power input terminal is connected to the input power through a second power converter.

[0023] A power supply system with two dual power supply circuits of the present invention includes the following first power supply system solution: The first power supply system scheme 1 includes the circuit scheme 3 in the aforementioned dual power supply circuit and the circuit scheme 12 in the aforementioned dual power supply circuit; the dual power supply circuit in the circuit scheme 3 is used as the primary stage, and the dual power supply circuit in the circuit scheme 12 is used as the secondary stage; The first negative electrode connection line in the dual power supply circuit of the secondary stage is connected to the first negative electrode connection line in the dual power supply circuit of the primary stage; The common end of the second single-pole double-throw switch in the dual-power supply circuit of the secondary stage is connected to the first positive connection line in the dual-power supply circuit of the primary stage; One end of the coil of the second intermediate relay in the secondary dual power supply circuit is connected to the first negative connection line in the secondary dual power supply circuit, and the other end is connected to the first positive connection line in the primary dual power supply circuit; The normally open end of the second single-pole double-throw switch in the dual-power supply circuit of the secondary stage is connected to the first positive connection line in the dual-power supply circuit of the primary stage.

[0024] First power supply system solution 2, based on the first power supply system solution 1, a first anti-reverse diode with a conduction direction pointing to the power output end of the main-stage dual power supply circuit is provided on the first positive electrode connecting line of the main-stage dual power supply circuit; The normally open end of the second single-pole double-throw switch in the dual-power supply circuit of the secondary stage is connected to the anode of the first anti-reverse diode on the first positive electrode connection line of the dual-power supply circuit of the primary stage; The common end of the second single-pole double-throw switch in the secondary-stage dual-power supply circuit is connected to the cathode of the first anti-reverse diode on the first positive electrode connection line of the primary-stage dual-power supply circuit.

[0025] The first power supply system solution three, based on the first power supply system solution one or the first power supply system solution two, further includes a first power converter, a second power converter, a third power converter and a fourth power converter; A first power input terminal in the dual power supply circuit of the main stage is connected to the input power through a first power converter; The second power input terminal in the dual power supply circuit of the main stage is connected to the input power through the second power converter; The first power input terminal of the dual power supply circuit of the secondary stage is connected to the input power through the third power converter; The second power input terminal in the secondary-stage dual-power supply circuit is connected to the input power through a fourth power converter.

[0026] A power supply system with three dual power supply circuits of the present invention includes the following second power supply system solution: The second power supply system scheme 1 includes the first power supply system scheme 1 in the power supply system having two dual power supply circuits and the circuit scheme 12 in the dual power supply circuit; the dual power supply circuit in the circuit scheme 12 serves as a secondary stage; The first negative electrode connection line in the dual power supply circuit of the secondary stage is connected to the first negative electrode connection line in the dual power supply circuit of the primary stage; The common end of the second single-pole double-throw switch in the secondary-stage dual-power supply circuit is connected to the first positive connection line in the primary-stage dual-power supply circuit; One end of the coil of the second intermediate relay in the secondary-stage dual power supply circuit is connected to the first negative electrode connection line in the secondary-stage dual power supply circuit, and the other end is connected to the common end of the second single-pole double-throw switch in the secondary-stage dual power supply circuit; The normally open end of the second single-pole double-throw switch in the secondary-stage dual-power supply circuit is connected to the first positive connection line in the primary-stage dual-power supply circuit.

[0027] Second power supply system scheme 2, based on the second power supply system scheme 1, a first positive pole connecting line of the dual power supply circuit of the main stage is provided with a first anti-reverse diode and a second anti-reverse diode whose conduction direction points to the power output end of the dual power supply circuit of the main stage; The normally open end of the second single-pole double-throw switch in the dual-power supply circuit of the secondary stage is connected to the anode of the first anti-reverse diode on the first positive electrode connection line of the dual-power supply circuit of the primary stage; The common end of the second single-pole double-throw switch in the dual-power supply circuit of the secondary stage is connected to the cathode of the first anti-reverse diode on the first positive electrode connection line of the dual-power supply circuit of the primary stage; The normally open end of the second single-pole double-throw switch in the secondary-stage dual-power supply circuit is connected to the anode of the second anti-reverse diode on the first positive electrode connection line of the primary-stage dual-power supply circuit; The common end of the second single-pole double-throw switch in the secondary-stage dual-power supply circuit is connected to the cathode of the second anti-reverse diode on the second positive electrode connection line of the primary-stage dual-power supply circuit.

[0028] The second power supply system scheme three, based on the second power supply system scheme one or the second power supply system scheme two, further includes a first power converter, a second power converter, a third power converter, a fourth power converter, a fifth power converter and a sixth power converter; A first power input terminal in the dual power supply circuit of the main stage is connected to the input power through a first power converter; The second power input terminal in the dual power supply circuit of the main stage is connected to the input power through the second power converter; The first power input terminal of the dual power supply circuit of the secondary stage is connected to the input power through the third power converter; The second power input terminal of the secondary-stage dual-power supply circuit is connected to the input power supply through a fourth power converter; The first power input terminal of the dual power supply circuit of the secondary stage is connected to the input power through the fifth power converter; The second power input terminal of the secondary-stage dual-power supply circuit is connected to the input power through a sixth power converter.

[0029] The beneficial effects of the present invention are as follows: as a pioneering invention, the present invention provides a dual power supply circuit and power supply system, including two power input terminals, a power output terminal for connecting a load and a first intermediate relay; the negative poles of the two power input terminals are connected together and then connected to the negative pole of the power output terminal through a first negative pole connecting line; the positive pole of the first power input terminal is connected in series with the normally open contact of the first intermediate relay and then connected to the positive pole of the power output terminal; the positive pole of the first power input terminal is also connected in series with the coil of the first intermediate relay and then connected to the first negative pole connecting line; the positive pole of the second power input terminal is connected in series with the normally closed contact of the first intermediate relay and then connected to the positive pole of the power output terminal. On the one hand, since the first power input terminal can be automatically switched to the second power input terminal when there is a fault through the power gain and loss of the coil of the first intermediate relay, the cost is low; on the other hand, since the normally open contact and the normally closed contact of the first intermediate relay are mechanical contacts, the internal resistance is extremely low once they are turned on, and they have the characteristics of continuous overcurrent without heating, so the occurrence of circuit burnout can be reduced, and the reliability of the power supply circuit can be further improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a structural schematic diagram of a dual power supply circuit provided by an embodiment of the present invention; Figure 2 It is a structural schematic diagram of a power supply system with three dual power supply circuits provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0032] The concept of the present invention is to add a redundant power supply to a single power supply circuit and use an intermediate relay to switch between the two power supplies.

[0033] Specifically, the dual power supply circuit includes two power input terminals, a power output terminal for connecting a load, and a first intermediate relay; the negative poles of the two power input terminals are connected together and then connected to the negative pole of the power output terminal through a first negative pole connecting line; the positive pole of the first power input terminal is connected in series with the normally open contact of the first intermediate relay and then connected to the positive pole of the power output terminal; the positive pole of the first power input terminal is also connected in series with the coil of the first intermediate relay and then connected to the first negative pole connecting line; the positive pole of the second power input terminal is connected in series with the normally closed contact of the first intermediate relay and then connected to the positive pole of the power output terminal.

[0034] An embodiment of a dual power supply circuit: Figure 1 is a schematic diagram of a dual power supply circuit provided by an embodiment of the present invention. Figure 1As shown, the dual power supply circuit includes two power input terminals, a power output terminal for connecting a load, and a first intermediate relay KM1.

[0035] Specifically, the negative poles of the two power input terminals are connected together and then connected to the negative pole of the power output terminal through the first negative pole connecting line; the positive pole of the first power input terminal is connected in series with the normally open contact of the first intermediate relay KM1, and then connected to the positive pole of the power output terminal; the positive pole of the first power input terminal is also connected in series with the coil of the first intermediate relay KM1 and then connected to the first negative pole connecting line; the positive pole of the second power input terminal is connected in series with the normally closed contact of the first intermediate relay KM1, and then connected to the positive pole of the power output terminal.

[0036] In order to make the circuit neat and beautiful, as an optional implementation, the output end of the normally open contact of the first intermediate relay KM1 and the output end of the normally closed contact of the first intermediate relay KM1 can be connected together and then connected to the positive pole of the power output end through the first positive connecting line.

[0037] As an optional implementation, the first intermediate relay KM1 may include a first single-pole double-throw switch. Then, the normally open terminal NO of the first single-pole double-throw switch is connected to the positive pole of the first power input terminal, the normally closed terminal NC is connected to the positive pole of the second power input terminal, and the common terminal COM is connected to the positive pole of the power output terminal through the first positive pole connecting line.

[0038] Among them, the normally open terminal NO and the common terminal COM of the first single-pole double-throw switch constitute the normally open contact NO-COM, which is also the normally open contact of the first intermediate relay KM1; the normally closed terminal NC and the common terminal COM of the first single-pole double-throw switch constitute the normally closed contact NC-COM, which is also the normally closed contact of the first intermediate relay KM1.

[0039] The following description will be given by taking the example that the first intermediate relay KM1 includes a first single-pole double-throw switch and a coil.

[0040] The dual power supply circuit provided in the embodiment of the present invention includes two power input terminals, one power output terminal and a first intermediate relay. The working principle of the dual power supply circuit is as follows: when there is no fault in the first power input terminal, the first power input terminal outputs a power supply voltage. After the coil of the first intermediate relay KM1 is energized, the normally closed contact of the first intermediate relay KM1 is disconnected, and the normally open contact of the first intermediate relay KM1 is closed, that is, the first single-pole double-throw switch in the first intermediate relay KM1 is switched from the normally closed contact NC-COM to the normally open contact NO-COM, then the normally closed contact of the first intermediate relay KM1 is switched from the "normally closed state" to the "normally open state", and the normally open contact of the first intermediate relay KM1 is switched from the "normally open state" to the "normally closed state", therefore, the power supply circuit from the first power input terminal to the rear-end load is connected, the power supply circuit from the second power input terminal to the rear-end load is disconnected, and the first power input terminal supplies power to the rear-end load.

[0041] When a fault occurs in the first power input terminal, the first power input terminal does not output the power supply voltage, and the coil of the first intermediate relay KM1 loses power. At this time, the normally closed contact of the first intermediate relay KM1 is closed, and the normally open contact of the first intermediate relay KM1 is disconnected, that is, the first single-pole double-throw switch in the first intermediate relay KM1 is switched from the normally open contact NO-COM to the normally closed contact NC-COM, and the normally closed contact of the first intermediate relay KM1 is switched from the "normally open state" to the "normally closed state", and the normally open contact of the first intermediate relay KM1 is switched from the "normally closed state" to the "normally open state", therefore, the power supply circuit from the first power input terminal to the rear-end load is disconnected, and the power supply circuit from the second power input terminal to the rear-end load is connected, and the second power input terminal supplies power to the rear-end load.

[0042] Since the first power input terminal and the second power input terminal can complement each other to supply power to the rear-end load, the reliability of the power supply circuit can be improved. In addition, since the first intermediate relay is used to complete the switching between the first power input terminal and the second power input terminal, the normally open contact and the normally closed contact of the first intermediate relay KM1 are both mechanical contacts, and once turned on, the internal resistance is extremely low, and continuous overcurrent can be generated without heating, which can further improve the reliability of the power supply circuit.

[0043] Since there is a switching time gap between the normally open contact and the normally closed contact of the first intermediate relay KM1 during the switching process, that is, there is a switching time gap during the switching of the first single-pole double-throw switch from the normally closed contact NC-COM to the normally open contact NO-COM or from the normally open contact NO-COM to the normally closed contact NC-COM. Although this switching time gap is very short, at the millisecond level, it will still cause complementary interruptions in the power supply between the first power input terminal and the second power output terminal, which may cause data loss and, in severe cases, cause restarting. Therefore, in order to avoid this situation, as an optional implementation, a dual power supply circuit provided in an embodiment of the present invention also includes a first diode D1 and a second diode D2.

[0044] The first diode D1 and the second diode D2 are a group of common cathode diodes, that is, the cathodes of the first diode D1 and the second diode D2 are connected together. The conduction voltage difference of the first diode D1 and the second diode D2 is in the range of [0.7 volts (V), 1V].

[0045] The cathodes of the first diode D1 and the second diode D2 are connected to the common terminal COM of the first single-pole double-throw switch; the anode of the first diode D1 is connected to the normally open terminal NO of the first single-pole double-throw switch; the anode of the second diode D2 is connected to the normally closed terminal NC of the first single-pole double-throw switch.

[0046] For two diodes with a common cathode, since the cathode potential is the same, the conduction priority of the two diodes with a common cathode depends on the anode potential of the two diodes, that is, whichever diode has a higher anode potential will be turned on first, and the other diode will be in the cut-off state. The diode that is turned on first will clamp the common cathode potential (that is, common cathode potential = anode potential - diode conduction voltage drop, and the silicon diode conduction voltage drop is generally in the range of 0.6-0.7V). When the anode potential deviation of the two diodes is less than 0.1V (the dual power supply voltage difference is less than 0.1V), the other diode will be in the cut-off state (does not have the conduction voltage drop condition).

[0047] When there is no fault in the first power input terminal, the normally closed contact NC-COM of the first single-pole double-throw switch switches to the normally open contact NO-COM. Before switching to the normally open contact NO-COM, since the potential of the normally open terminal NO of the first single-pole double-throw switch is the same as the potential of the normally closed terminal NC of the first single-pole double-throw switch, and is higher than the potential of the common terminal COM of the first single-pole double-throw switch, at this time, the first diode D1 and the second diode D2 are both turned on, and the entire dual power supply circuit is powered by the first power input terminal and the second power input terminal to supply power to the rear-end load; when the first single-pole double-throw switch has switched to its normally open contact NO-COM, the first diode D1 is bypassed. At this time, the potentials of the normally open terminal NO of the first single-pole double-throw switch, the normally closed terminal NV of the first single-pole double-throw switch and the common terminal COM of the first single-pole double-throw switch are equal, then the second diode D2 is turned off, and only the first power input terminal of the entire dual power supply circuit supplies power to the rear-end load.

[0048] When there is a fault in the first power input terminal, the normally open contact NO-COM of the first single-pole double-throw switch switches to the normally closed contact NC-COM of the first single-pole double-throw switch. Before switching to the normally closed contact NC-COM of the first single-pole double-throw switch, due to the fault of the first input power, the first diode D1 is cut off. Since the potential at the normally closed terminal NC of the first single-pole double-throw switch is higher than the potential at the common terminal COM of the first single-pole double-throw switch, the second diode D2 is turned on. When the first single-pole double-throw switch has switched to its normally closed contact NC-COM, the second diode D2 is bypassed. At this time, only the second power input terminal of the entire dual power supply circuit supplies power to the rear-end load.

[0049] Since voltage can be provided to the rear-end load through the first diode D1 and the second diode D2 during the switching interval to ensure smooth and uninterrupted switching, the continuous stability of the power supply for the load can be guaranteed to avoid data loss or restart.

[0050] In order to facilitate the staff to observe whether the status of the first power input terminal and the status of the second power input terminal are normal, as an optional implementation, the dual power supply circuit provided in the embodiment of the present invention also includes a fault feedback module 1 connected in parallel at both ends of the first power input terminal and a fault feedback module 2 connected in parallel at both ends of the second power input terminal.

[0051] The fault feedback module 1 and the fault feedback module 2 each include an indicator light HG. For the convenience of description, the indicator light in the fault feedback module 1 is named as the first indicator light, and the indicator light in the fault feedback module 2 is named as the second indicator light.

[0052] Then, the positive pole of the first indicator light is connected to the positive pole of the first power input terminal, and the negative pole of the first indicator light is connected to the negative pole of the first power input terminal; the positive pole of the second indicator light is connected to the positive pole of the second power input terminal, and the negative pole of the second indicator light is connected to the negative pole of the second power input terminal.

[0053] When there is no fault at the first power input terminal, the first indicator light will illuminate, and when there is a fault at the first power input terminal, the first indicator light will not illuminate; when there is no fault at the second power input terminal, the second indicator light will illuminate, and when there is a fault at the second power input terminal, the second indicator light will not illuminate. Therefore, the staff can know whether the first power input terminal is faulty by observing whether the first indicator light is on or off, and can know whether the second power input terminal is faulty by observing whether the second indicator light is on or off.

[0054] In order to facilitate the background system to detect the status of the first power input circuit and the second power input circuit and facilitate intelligent management, as an optional implementation, the fault module 1 and the fault module 2 may also include a relay KA. For the convenience of description, the relay KA in the fault feedback module 1 is named the first relay, and the relay KA in the fault feedback module 2 is named the second relay.

[0055] Then, the coil of the first relay is connected in parallel at both ends of the first indicator light; the normally open contact of the first relay is used to be connected in parallel with the signal acquisition device in the background system; the coil of the second relay is connected in parallel at both ends of the second indicator light; the normally open contact of the second relay is used to be connected in parallel with the signal acquisition device in the background system.

[0056] In order to reduce the volume of the power supply circuit, as an optional implementation, the first relay and the second relay are both micro relays.

[0057] Furthermore, as an optional implementation, the normally closed contacts of the first relay may be connected in parallel with the signal acquisition device in the background system instead of the normally open contacts of the first relay being connected in parallel with the signal acquisition device in the background system; the normally closed contacts of the second relay may be connected in parallel with the signal acquisition device in the background system instead of the normally open contacts of the second relay being connected in parallel with the signal acquisition device in the background system.

[0058] The present invention does not specifically limit whether the normally closed contact of the first relay is connected in parallel with the signal acquisition device in the background system, or whether the normally open contact of the first relay is connected in parallel with the signal acquisition device in the background system. The present embodiment will be exemplified by taking the example of using the normally open contact of the first relay to be connected in parallel with the signal acquisition device in the background system.

[0059] The present invention does not specifically limit whether the normally closed contact of the second relay is connected in parallel with the signal acquisition device in the background system, or whether the normally open contact of the second relay is connected in parallel with the signal acquisition device in the background system. The present embodiment will be exemplified by taking the normally open contact of the second relay connected in parallel with the signal acquisition device in the background system as an example.

[0060] When there is no fault at the first power input terminal, the coil of the first relay is energized and the normally open contact of the first relay is closed. At this time, the signal acquisition device in the background system can collect a signal; when there is a fault at the first power input terminal, the coil of the first relay loses power and the normally open contact of the first relay is disconnected. At this time, the signal acquisition device in the background system can collect another signal. Therefore, the background system can determine whether there is a fault at the first power input terminal by monitoring the signal form collected by the signal acquisition device.

[0061] When there is no fault at the second power supply input terminal, the coil of the second relay is energized and the normally open contact of the second relay is closed. At this time, the signal acquisition device in the background system can collect a signal; when there is a fault at the second power supply system input terminal, the coil of the second relay loses power and the normally open contact of the second relay is disconnected. At this time, the signal acquisition device in the background system can collect another signal. Therefore, the background system can determine whether there is a fault at the second power supply input terminal by monitoring the signal form collected by the signal acquisition device.

[0062] Since the voltage types and voltage levels that the front-end power supply can provide are diverse, it is possible that the voltage provided by the front-end power supply is not suitable for the back-end load. In order to solve this problem, as an optional implementation, the dual power supply circuit provided in an embodiment of the present invention also includes a first power converter P1 and a second power converter P2.

[0063] Specifically, the first power input terminal is connected to the input power 10 through the first power converter P1 ; the second power input terminal is connected to the input power 10 through the second power converter P2 .

[0064] Among them, the types of the first power converter P1 and the second power converter P2 are related to the load requirements of the back end, and can be an alternating current (AC) to direct current (DC) power converter, or a DC / DC power converter (i.e., a high voltage / low voltage converter), etc. The present invention does not make any special limitation on this. The following description of this embodiment takes the example that both the first power converter P1 and the second power converter P2 are DC / DC power converters.

[0065] In order to facilitate monitoring of the status of the power output terminal, as an optional implementation, the dual power supply circuit provided in the embodiment of the present invention further includes a fault feedback module 3.

[0066] The fault feedback module 3 includes an indicator light HG. For the convenience of description, the indicator light HG in the fault feedback module 3 is referred to as the third indicator light. Then, the positive electrode of the third indicator light is connected to the first positive electrode connection line, and the negative electrode of the third indicator light is connected to the first negative electrode connection line.

[0067] In order to facilitate the background system to detect the state of the power output and facilitate intelligent management, as an optional implementation, the fault module 3 can also include a relay KA. For the convenience of description, the relay KA in the fault feedback module 3 is named the third relay.

[0068] Then, the coil of the third relay is connected in parallel to the two ends of the third indicator light; the normally open contact of the third relay is used to be connected in parallel with the signal acquisition device in the background system.

[0069] Further, as an optional implementation, the normally closed contact of the third relay may be connected in parallel with the signal acquisition device in the background system, rather than the normally open contact of the third relay being connected in parallel with the signal acquisition device in the background system.

[0070] The present invention does not specifically limit whether the normally closed contact of the third relay is connected in parallel with the signal acquisition device in the background system, or whether the normally open contact of the third relay is connected in parallel with the signal acquisition device in the background system. The present embodiment will be exemplified by taking the normally open contact of the third relay connected in parallel with the signal acquisition device in the background system as an example.

[0071] In order to reduce the volume of the power supply circuit, as an optional implementation, the third relay is a micro relay.

[0072] The working principle of the third indicator light and the third relay in the fault module 3 is similar to the working principle of the first indicator light and the first relay in the aforementioned fault module 1, and will not be repeated here.

[0073] In order to increase the service life of the power supply system, the dual power supply circuit provided in the embodiment of the present invention may be architecturally expanded. As an optional implementation, the dual power supply circuit provided in the embodiment of the present invention further includes a second intermediate relay KM2.

[0074] Specifically, the normally closed contact of the second intermediate relay KM2 is connected in series with the first positive connecting line.

[0075] As an optional embodiment, the second intermediate relay KM2 includes a second single-pole double-throw switch; the normally open terminal NO of the second single-pole double-throw switch is suspended; the normally closed terminal NC of the second single-pole double-throw switch is connected to the common terminal COM of the first single-pole double-throw switch; the normally open terminal NO of the second single-pole double-throw switch and the common terminal COM of the second single-pole double-throw switch constitute the normally open contact of the second intermediate relay KM2; the normally closed terminal NC of the second single-pole double-throw switch and the common terminal COM of the second single-pole double-throw switch constitute the normally closed contact of the second intermediate relay KM2.

[0076] In order to reduce the occurrence of data loss or circuit restart during the switching process, as an optional implementation, the dual power supply circuit provided in the embodiment of the present invention further includes a third diode D3. The anode of the third diode D3 is connected to the normally closed terminal NC of the second single-pole double-throw switch; the cathode of the third diode D3 is connected to the common terminal COM of the second single-pole double-throw switch.

[0077] The dual power supply circuit provided by the embodiment of the present invention includes two power input terminals, a power output terminal for connecting a load, and a first intermediate relay; the negative poles of the two power input terminals are connected together and then connected to the negative pole of the power output terminal through a first negative pole connecting line; the positive pole of the first power input terminal is connected in series with the normally open contact of the first intermediate relay and then connected to the positive pole of the power output terminal; the positive pole of the first power input terminal is also connected in series with the coil of the first intermediate relay and then connected to the first negative pole connecting line; the positive pole of the second power input terminal is connected in series with the normally closed contact of the first intermediate relay and then connected to the positive pole of the power output terminal. On the one hand, since the first power input terminal can be automatically switched to the second power input terminal when there is a fault through the power gain and loss of the coil of the first intermediate relay, the cost is low; on the other hand, since the normally open contact and the normally closed contact of the first intermediate relay are mechanical contacts, the internal resistance is extremely low once they are turned on, and they have the characteristics of continuous overcurrent without heating, so the occurrence of circuit burnout can be reduced, and the reliability of the power supply circuit can be further improved.

[0078] An embodiment of a power supply system: Embodiment 1: An embodiment of the present invention provides a power supply system with two dual power supply circuits, including two dual power supply circuits.

[0079] Among them, one of the two dual power supply circuits is used as the main stage, and the other is used as the secondary stage dual power supply circuit. The dual power supply circuit of the main stage uses the dual power supply circuit in the aforementioned "an embodiment of a dual power supply circuit" without the second intermediate relay KM2 but the first intermediate relay includes a first single-pole double-throw switch, and the dual power supply circuit of the secondary stage uses the dual power supply circuit in the aforementioned "an embodiment of a dual power supply circuit" with the second intermediate relay KM2 and the second intermediate relay KM2 includes a second single-pole double-throw switch, and the first intermediate relay KM1 includes a first single-pole double-throw switch.

[0080] It should be noted that, for the specific introduction of the dual power supply circuit of the main stage and the dual power supply circuit of the secondary stage, please refer to the relevant description in the aforementioned "an embodiment of a dual power supply circuit", which will not be repeated here. Only the connection relationship between the dual power supply circuit of the main stage and the dual power supply circuit of the secondary stage is introduced here.

[0081] First, the connection relationship between the dual power supply circuit of the main stage and the dual power supply circuit of the secondary stage is introduced. Specifically, the first negative connection line in the dual power supply circuit of the secondary stage is connected to the first negative connection line in the dual power supply circuit of the main stage; the common end COM of the second single-pole double-throw switch in the dual power supply circuit of the secondary stage is connected to the first positive connection line in the dual power supply circuit of the main stage; one end of the coil of the second intermediate relay KM2 in the dual power supply circuit of the secondary stage is connected to the first negative connection line in the dual power supply circuit of the secondary stage, and the other end is connected to the first positive connection line in the dual power supply circuit of the main stage; the normally open end NO of the second single-pole double-throw switch in the dual power supply circuit of the secondary stage is connected to the first positive connection line in the dual power supply circuit of the main stage.

[0082] In order to prevent the power supply current from flowing back and causing damage to the main-stage dual power supply circuit when the secondary-stage dual power supply circuit supplies power to the rear-end load, as an optional implementation, the power supply system of two dual power supply circuits provided in the embodiment of the present invention also includes a first anti-reverse diode D4 arranged on the first positive pole connection line of the main-stage dual power supply circuit and with the conduction direction pointing to the power output end of the main-stage dual power supply circuit.

[0083] When the first anti-reverse diode D4 is provided, the normally-open terminal NO of the second single-pole double-throw switch in the secondary-stage dual-power supply circuit is connected to the anode of the first anti-reverse diode D4 on the first positive connection line of the primary-stage dual-power supply circuit; the common terminal COM of the second single-pole double-throw switch in the secondary-stage dual-power supply circuit is connected to the cathode of the first anti-reverse diode D4 on the first positive connection line of the primary-stage dual-power supply circuit.

[0084] As an optional implementation, the first power input terminal and the second power input terminal of the main-stage dual power supply circuit and the first power input terminal and the second power input terminal of the secondary-stage dual power supply circuit can share an input power supply, and the power output terminal of the main-stage dual power supply circuit and the power output terminal of the secondary-stage dual power supply circuit can supply power to the same load.

[0085] In order to enable the front-end power supply to better meet the power demand of the back-end load, as an optional implementation, the power supply system with two dual power supply circuits provided in the embodiment of the present invention also includes: a first power converter, a second power converter, a third power converter and a fourth power converter; the first power input terminal in the main-stage dual power supply circuit is connected to the input power through the first power converter; the second power input terminal in the main-stage dual power supply circuit is connected to the input power through the second power converter; the first power input terminal in the secondary-stage dual power supply circuit is connected to the input power through the third power converter; the second power input terminal in the secondary-stage dual power supply circuit is connected to the input power through the fourth power converter.

[0086] The input power source may be a battery cluster.

[0087] Among them, the battery cluster can also be connected to the energy storage inverter (Power Conversion System, PCS) in the energy conversion system.

[0088] Furthermore, in order to facilitate manual control of a power supply system having two dual power supply circuits, as an optional implementation, a manual switch QF can be set on the connection line between the input power supply and the first power converter, the second power converter, the third power converter and the fourth power converter.

[0089] The working principle of the dual power supply circuit provided by the embodiment of the present invention is as follows: when the dual power supply circuit of the main stage is fault-free, the dual power supply circuit of the secondary stage does not work, and only when both the first power input terminal and the second power input terminal in the dual power supply circuit of the main stage are faulty, the dual power supply circuit of the secondary stage starts to work, and the first power input terminal in the dual power supply circuit of the secondary stage outputs voltage first, and when the first power input terminal in the dual power supply circuit of the secondary stage outputs faulty, the second power input terminal in the dual power supply circuit of the secondary stage starts to output voltage. Since one more set of dual power supply circuits is provided, the service life and reliability of the power supply system can be improved.

[0090] During the switching interval between the dual power supply circuit of the primary stage and the dual power supply circuit of the secondary stage, the third diode D3 in the negative dual power supply circuit can continue current, thus ensuring smooth and uninterrupted circuit switching and continuous stability of the load working power supply.

[0091] The power supply system with two dual power supply circuits provided by the embodiment of the present invention, on the one hand, since each electrical component in the dual power supply circuit of the main and secondary stages is selected from mature shelf products on the market, there is no need to formulate development and verification; on the second hand, since the normally open contacts and normally closed contacts of the first intermediate relay and the second intermediate relay used are both mechanical contacts, once they are turned on, the internal resistance is extremely low, and continuous overcurrent can be generated without heat. Therefore, compared with the existing solutions using semiconductor devices such as diodes or MOS tubes, there is no situation where the circuit will be burned out, so the reliability of the power supply system can be improved, and in addition, the power loss is low; on the third hand, since the first intermediate relay and the two common cathode diodes in the dual power supply circuit of the main and secondary stages are designed in parallel, the power supply circuit will not be paralyzed if any of them fails or fails, which can further improve the stability of the power supply system; on the fourth hand, when the dual power supply circuit of the main stage switches to the dual power supply circuit of the secondary stage, since the two ends of the normally closed contact of the second intermediate relay in the dual power supply circuit of the secondary stage are connected in parallel The third diode can play the role of freewheeling, ensure smooth and uninterrupted circuit switching, ensure that the power supply system can continuously output a stable voltage, and reduce the loss or restart of load data; fifthly, due to the addition of a second intermediate relay for architecture expansion, it is more practical than the prior art; sixthly, since the dual power supply circuit of the secondary stage will only be started when both power input ends in the dual power supply circuit of the main stage are faulty, it has priority, which can reduce the occurrence of problems such as chaotic working sequence of each unit or random uncontrollable problems; sixthly, since both the dual power supply circuits of the main and secondary stages have a fault feedback module, it is possible to observe the indicator light and / or the status indication of the micro-relay in the fault feedback module to understand whether there is a problem with the power supply system. When there is a problem, the problematic area can be quickly located for easy testing; seventhly, compared with the solution of using a military-grade power supply, or a solution of using a special detection circuit and a special microprocessor, it has the advantage of low cost.

[0092] Embodiment 2: Embodiment 2 adds a dual power supply circuit on the basis of Embodiment 1, thereby forming a power supply system with three dual power supply circuits provided in the embodiment of the present invention.

[0093] The newly added dual power supply circuit selects the aforementioned "an embodiment of a dual power supply circuit" in which there is a second intermediate relay KM2 and the second intermediate relay KM2 includes a second single-pole double-throw switch, the first intermediate relay KM1 includes a dual power supply circuit in the form of a first single-pole double-throw switch, and the newly added dual power supply circuit serves as a secondary-stage. Therefore, the power supply system with three dual power supply circuits provided in the embodiment of the present invention includes a main-stage dual power supply circuit, a secondary-stage dual power supply circuit and a secondary-stage dual power supply circuit.

[0094] Figure 2 FIG. 1 is a schematic diagram of a power supply system having three dual power supply circuits provided by an embodiment of the present invention. Figure 2 As shown, the power supply system with three dual power supply circuits includes a minimum unit 1 (i.e., a dual power supply circuit of the main stage), a minimum unit 2 (i.e., a dual power supply circuit of the secondary stage) and a minimum unit 3 (i.e., a dual power supply circuit of the sub-secondary stage).

[0095] It should be noted that, since the connection relationship between the dual power supply circuit of the main stage and the dual power supply circuit of the secondary stage has been described in detail in Example 2, it will not be repeated here. Here, only the connection relationship between the dual power supply circuit of the secondary stage and the dual power supply circuit of the main stage and the dual power supply circuit of the secondary stage is described.

[0096] The connection relationship between the secondary-stage dual power supply circuit and the primary-stage dual power supply circuit and the secondary-stage dual power supply circuit is specifically as follows: the first negative pole connection line in the secondary-stage dual power supply circuit is connected to the first negative pole connection line in the primary-stage dual power supply circuit; the common end COM of the second single-pole double-throw switch in the secondary-stage dual power supply circuit is connected to the first positive pole connection line in the primary-stage dual power supply circuit; one end of the coil of the second intermediate relay KM2 in the secondary-stage dual power supply circuit is connected to the first negative pole connection line in the secondary-stage dual power supply circuit, and the other end is connected to the common end COM of the second single-pole double-throw switch in the secondary-stage dual power supply circuit; the normally open end NO of the second single-pole double-throw switch in the secondary-stage dual power supply circuit is connected to the first positive pole connection line in the primary-stage dual power supply circuit.

[0097] In order to prevent the power supply current from flowing back and causing damage to the main-stage dual power supply circuit when the secondary-stage dual power supply circuit supplies power to the rear-end load, as an optional implementation, the power supply system with three dual power supply circuits provided in the embodiment of the present invention, on the basis of Embodiment 2, also includes a second anti-reverse diode D5 which is arranged on the first positive pole connection line of the main-stage dual power supply circuit and has a conduction direction pointing to the power output terminal of the main-stage dual power supply circuit.

[0098] When the second anti-reverse diode D5 is provided, the normally-open terminal NO of the second single-pole double-throw switch in the secondary-stage dual-power supply circuit is connected to the anode of the second anti-reverse diode D5 on the first positive connection line of the primary-stage dual-power supply circuit; the common terminal COM of the second single-pole double-throw switch in the secondary-stage dual-power supply circuit is connected to the cathode of the second anti-reverse diode D5 on the first positive connection line of the primary-stage dual-power supply circuit.

[0099] As an optional implementation, the first power input terminal and the second power input terminal of the main-stage dual power supply circuit, the first power input terminal and the second power input terminal of the secondary-stage dual power supply circuit, and the first power input terminal and the second power input terminal of the sub-sub-stage dual power supply circuit can share an input power supply, and the power output terminal of the main-stage dual power supply circuit, the power output terminal of the secondary-stage dual power supply circuit, and the power output terminal of the sub-sub-stage dual power supply circuit can supply power to the same load.

[0100] The loads may include battery management systems, fire protection, fans, etc.

[0101] In order to make the front-end power supply better meet the power demand of the back-end load, as an optional implementation, the power supply system with three dual power supply circuits provided in the embodiment of the present invention also includes a fifth power converter and a sixth power converter added on the basis of Example 2.

[0102] That is, the first power input terminal in the dual power supply circuit of the main stage is connected to the input power through the first power converter; the second power input terminal in the dual power supply circuit of the main stage is connected to the input power through the second power converter; the first power input terminal in the dual power supply circuit of the secondary stage is connected to the input power through the third power converter; the second power input terminal in the dual power supply circuit of the secondary stage is connected to the input power through the fourth power converter; the first power input terminal in the dual power supply circuit of the sub-secondary stage is connected to the input power through the fifth power converter; the second power input terminal in the dual power supply circuit of the secondary stage is connected to the input power through the sixth power converter.

[0103] The input power source may be a battery cluster driven by a motor. The first power converter, the second power converter, the third power converter, the fourth power converter, the fifth power converter and the sixth power converter are all DC / DC power converters that can convert a high-voltage DC input of 200V to 800V into a low-voltage DC of 24V.

[0104] Furthermore, in order to facilitate manual control of a power supply system having three dual power supply circuits, as an optional implementation, a manual switch QF can be set on the connection line between the input power supply and the first power converter, the second power converter, the third power converter, the fourth power converter, the fifth power converter and the sixth power converter.

[0105] The working principle of the dual power supply circuit with three power supplies provided by the embodiment of the present invention is as follows: when the dual power supply circuit of the main stage is fault-free, the dual power supply circuit of the secondary stage and the dual power supply circuit of the secondary stage do not work, and when both the first power input terminal and the second power input terminal in the dual power supply circuit of the main stage are faulty, the dual power supply circuit of the secondary stage starts to work. The first power input terminal in the dual power supply circuit of the secondary stage outputs a voltage first, and when the first power input terminal in the dual power supply circuit of the secondary stage outputs a fault, the second power input terminal in the dual power supply circuit of the secondary stage starts to output a voltage, and when the second power input terminal in the dual power supply circuit of the secondary stage outputs a fault, the dual power supply circuit of the secondary stage starts to work. The first power input terminal in the dual power supply circuit of the secondary stage outputs a voltage first, and when the first power input terminal in the dual power supply circuit of the secondary stage outputs a fault, the second power input terminal in the dual power supply circuit of the secondary stage starts to output a voltage. Compared with a power supply system with two dual power supply circuits, two more sets of dual power supply circuits are provided, so the service life and reliability of the power supply system can be further improved.

[0106] The power supply system with three dual power supply circuits provided in the embodiment of the present invention can achieve similar beneficial effects as the aforementioned "a power supply system with two dual power supply circuits", which will not be repeated here.

Claims

1. A dual power supply circuit, characterized in that: It includes two power input terminals, a power output terminal for connecting a load, and a first intermediate relay; The negative electrodes of the two power input terminals are connected together and then connected to the negative electrode of the power output terminal through a first negative electrode connecting line; The positive electrode of the first power input terminal is connected in series with the normally open contact of the first intermediate relay and then connected to the positive electrode of the power output terminal; the positive electrode of the first power input terminal is also connected in series with the coil of the first intermediate relay and then connected to the first negative electrode connection line; The positive electrode of the second power input terminal is connected in series with the normally closed contact of the first intermediate relay, and then connected to the positive electrode of the power output terminal.

2. The dual power supply circuit according to claim 1, characterized in that: After the output end of the normally open contact of the first intermediate relay and the output end of the normally closed contact of the first intermediate relay are connected, they are connected to the positive electrode of the power output end through the first positive electrode connecting line.

3. The dual power supply circuit according to claim 1, characterized in that: The first intermediate relay comprises a first single-pole double-throw switch; The normally open end of the first single-pole double-throw switch is connected to the positive electrode of the first power input terminal, the normally closed end is connected to the positive electrode of the second power input terminal, and the common end is connected to the positive electrode of the power output terminal through the first positive electrode connecting line; The normally open end and the common end of the first single-pole double-throw switch constitute the normally open contact of the first intermediate relay, and the normally closed end and the common end of the first single-pole double-throw switch constitute the normally closed contact of the first intermediate relay.

4. The dual power supply circuit according to claim 3, characterized in that: Also includes a diode whose two cathodes are connected together and then connected to the common end of the first single-pole double-throw switch; The anode of the first diode is connected to the normally-open end of the first single-pole double-throw switch; The anode of the second diode is connected to the normally closed terminal of the first single-pole double-throw switch.

5. The dual power supply circuit according to claim 1, characterized in that: Also included is a first indicator light; The positive electrode of the first indicator light is connected to the positive electrode of the first power input terminal; The cathode of the first indicator light is connected to the cathode of the first power input terminal.

6. The dual power supply circuit according to claim 5, characterized in that: Also included is a first relay; The coil of the first relay is connected in parallel to the two ends of the first indicator light; the normally open contact of the first relay is used to be connected in parallel with the signal acquisition device in the background system.

7. The dual power supply circuit according to claim 1, characterized in that: Also including a second indicator light; The positive electrode of the second indicator light is connected to the positive electrode of the second power input terminal; The cathode of the second indicator light is connected to the cathode of the second power input terminal.

8. The dual power supply circuit according to claim 7, characterized in that: Also included is a second relay; The coil of the second relay is connected in parallel to the two ends of the second indicator light; the normally open contact of the second relay is used to be connected in parallel with the signal acquisition device in the background system.

9. The dual power supply circuit according to claim 2 or 3, characterized in that: Also included is a third indicator light; The positive electrode of the third indicator light is connected to the first positive electrode connecting wire; The cathode of the third indicator light is connected to the first cathode connecting wire.

10. The dual power supply circuit according to claim 9, characterized in that: Also included is a third relay; The coil of the third relay is connected in parallel to the two ends of the third indicator light; the normally open contact of the third relay is used to be connected in parallel with the signal acquisition device in the background system.

11. The dual power supply circuit according to claim 3, characterized in that: Also includes a second intermediate relay; The normally closed contact of the second intermediate relay is connected in series to the first positive connecting line.

12. The dual power supply circuit according to claim 11, characterized in that: The second intermediate relay comprises a second single-pole double-throw switch; The normally open end of the second single-pole double-throw switch is suspended; The normally closed end of the second single-pole double-throw switch is connected to the common end of the first single-pole double-throw switch; The normally open end of the second single-pole double-throw switch and the common end of the second single-pole double-throw switch constitute a normally open contact of the second intermediate relay; The normally closed end of the second single-pole double-throw switch and the common end of the second single-pole double-throw switch constitute a normally closed contact of the second intermediate relay.

13. The dual power supply circuit according to claim 12, characterized in that: Also including a third diode; An anode of the third diode is connected to a normally closed end of the second single-pole double-throw switch; A cathode of the third diode is connected to the common terminal of the second single-pole double-throw switch.

14. The dual power supply circuit according to claim 1, characterized in that: Also included is a first power converter and a second power converter; The first power input terminal is connected to an input power source through the first power converter; The second power input terminal is connected to the input power through the second power converter.

15. A power supply system having two dual power supply circuits, characterized in that: comprising a dual power supply circuit as claimed in claim 3 as a primary stage, and a dual power supply circuit as claimed in claim 12 as a secondary stage; The first negative electrode connection line in the dual power supply circuit of the secondary stage is connected to the first negative electrode connection line in the dual power supply circuit of the primary stage; The common end of the second single-pole double-throw switch in the dual-power supply circuit of the secondary stage is connected to the first positive connection line in the dual-power supply circuit of the primary stage; One end of the coil of the second intermediate relay in the secondary dual power supply circuit is connected to the first negative connection line in the secondary dual power supply circuit, and the other end is connected to the first positive connection line in the primary dual power supply circuit; The normally open end of the second single-pole double-throw switch in the dual-power supply circuit of the secondary stage is connected to the first positive connection line in the dual-power supply circuit of the primary stage.

16. The power supply system with two dual power supply circuits according to claim 15, characterized in that: A first anti-reverse diode is provided on the first positive pole connection line of the dual power supply circuit of the main stage, the conduction direction of which points to the power output end of the dual power supply circuit of the main stage; The normally open end of the second single-pole double-throw switch in the dual-power supply circuit of the secondary stage is connected to the anode of the first anti-reverse diode on the first positive electrode connection line of the dual-power supply circuit of the primary stage; The common end of the second single-pole double-throw switch in the secondary-stage dual-power supply circuit is connected to the cathode of the first anti-reverse diode on the first positive electrode connection line of the primary-stage dual-power supply circuit.

17. The power supply system with two dual power supply circuits according to claim 15 or 16, characterized in that: Also included is a first power converter, a second power converter, a third power converter and a fourth power converter; A first power input terminal in the dual power supply circuit of the main stage is connected to the input power through a first power converter; The second power input terminal in the dual power supply circuit of the main stage is connected to the input power through a second power converter; The first power input terminal of the secondary dual power supply circuit is connected to the input power through a third power converter; The second power input terminal in the secondary-stage dual-power supply circuit is connected to the input power through a fourth power converter.

18. A power supply system having three dual power supply circuits, characterized in that: A power supply system comprising two dual power supply circuits as claimed in claim 15 and a dual power supply circuit as claimed in claim 12 as a secondary stage; The first negative electrode connection line in the dual power supply circuit of the secondary stage is connected to the first negative electrode connection line in the dual power supply circuit of the primary stage; The common end of the second single-pole double-throw switch in the secondary-stage dual-power supply circuit is connected to the first positive connection line in the primary-stage dual-power supply circuit; One end of the coil of the second intermediate relay in the secondary-stage dual power supply circuit is connected to the first negative electrode connection line in the secondary-stage dual power supply circuit, and the other end is connected to the common end of the second single-pole double-throw switch in the secondary-stage dual power supply circuit; The normally open end of the second single-pole double-throw switch in the secondary-stage dual-power supply circuit is connected to the first positive connection line in the primary-stage dual-power supply circuit.

19. The power supply system with three dual power supply circuits according to claim 18, characterized in that: A first positive electrode connection line of the dual power supply circuit of the main stage is provided with a first anti-reverse diode and a second anti-reverse diode whose conduction direction points to the power output end of the dual power supply circuit of the main stage; The normally open end of the second single-pole double-throw switch in the dual-power supply circuit of the secondary stage is connected to the anode of the first anti-reverse diode on the first positive electrode connection line of the dual-power supply circuit of the primary stage; The common end of the second single-pole double-throw switch in the dual-power supply circuit of the secondary stage is connected to the cathode of the first anti-reverse diode on the first positive electrode connection line of the dual-power supply circuit of the primary stage; The normally open end of the second single-pole double-throw switch in the secondary-stage dual-power supply circuit is connected to the anode of the second anti-reverse diode on the first positive electrode connection line of the primary-stage dual-power supply circuit; The common end of the second single-pole double-throw switch in the secondary-stage dual-power supply circuit is connected to the cathode of the second anti-reverse diode on the second positive electrode connection line of the primary-stage dual-power supply circuit.

20. The power supply system with three dual power supply circuits according to claim 18 or 19, characterized in that: Also includes a first power converter, a second power converter, a third power converter, a fourth power converter, a fifth power converter and a sixth power converter; A first power input terminal in the dual power supply circuit of the main stage is connected to the input power through a first power converter; The second power input terminal in the dual power supply circuit of the main stage is connected to the input power through a second power converter; The first power input terminal of the secondary dual power supply circuit is connected to the input power through a third power converter; The second power input terminal of the secondary-stage dual-power supply circuit is connected to the input power supply through a fourth power converter; The first power input terminal of the dual power supply circuit of the secondary stage is connected to the input power supply through a fifth power converter; The second power input terminal in the secondary-stage dual-power supply circuit is connected to the input power through a sixth power converter.

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