A dual-input switching circuit

Abstract

A dual-input switching circuit includes: input voltage 1, input voltage 2, an intelligent switching unit, an auxiliary power supply unit, and a critical power supply unit. The intelligent switching unit is connected to input voltage 1, input voltage 2, and the auxiliary power supply unit, and connects either input voltage 1 or input voltage 2 to the critical power supply unit. The intelligent switching unit includes a relay group, a dual-input control circuit, and an electromagnetic interference filter 3. Input voltage 1 is connected to the normally open contacts B1 and C1 of relays 2 and 3, and to the normally closed contacts E1 and F1 of relay 5. Input voltage 2 is connected to the normally open contacts A1 and D1 of relays 1 and 4. Contact A2 of relay 1 and contact B2 of relay 2 are connected, and contact C2 of relay 3 and contact D2 of relay 4 are connected, each connected to the critical power supply circuit through the electromagnetic interference filter 3. This invention can effectively reduce device costs, and the series connection of two relays increases the contact spacing and improves dielectric strength.

Description

Technical Field

[0001] This invention relates to the field of power supply technology, and more specifically to a dual-input switching circuit. Background Technology

[0002] Modern power supplies have increasingly higher requirements for power density, stability, and safety. In many applications, double redundancy is used to ensure power supply reliability. However, this method is costly and space-consuming, leading to the emergence of products with dual-input methods for single power supplies. Existing dual-input switching circuits mostly use a combination of multiple relays, which results in a relatively complex circuit structure and a large footprint.

[0003] Patent No. 2020108563645 discloses a dual-input circuit, characterized in that: the dual-input circuit includes a first input port, a second input port, an intelligent switching unit, an auxiliary power supply unit, and a key power supply unit; the first input port receives a first input voltage, the second input port receives a second input voltage, and the auxiliary power supply unit is connected in parallel between the first and second input ports; the intelligent switching unit connects the first input port, the second input port, and the auxiliary power supply unit to provide one of the first and second input voltages to the key power supply unit and output it. Using a contactor as the switching device is more suitable for medium to high power applications. Furthermore, the contactor used is a single double-pole double-throw contactor, employing a single dual-input auxiliary power supply. Compared to a solution using two single-input auxiliary power supplies, this reduces the required space and lowers costs.

[0004] However, this invention uses a contactor, which is manufactured with precision and uses high-grade materials, resulting in a higher price and increasing the cost of the circuit. Compared to a solution using multiple relays, the cost is higher. Furthermore, the magnetic latching contactor used in the aforementioned patent has an unstable initial state, making the control logic more complex. Summary of the Invention

[0005] To address the aforementioned technical problems, this technical solution provides a dual-input switching circuit that uses five relays to control power supply switching, with two relays configured on each power supply, effectively solving the above-mentioned problems.

[0006] This invention is achieved through the following technical solution:

[0007] A dual-input switching circuit includes: input voltage 1, input voltage 2, intelligent switching unit, auxiliary power supply unit, and critical power supply unit. The intelligent switching unit is connected to input voltage 1, input voltage 2, and auxiliary power supply unit, and connects either input voltage 1 or input voltage 2 to the critical power supply unit. The intelligent switching unit includes a relay group, a dual-input control circuit, and an electromagnetic interference filter 3. Input voltage 1 is connected to the normally open contacts B1 and C1 of relays 2 and 3, and to the normally closed contacts E1 and F1 of relay 5. Input voltage 2 is connected to the normally open contacts A1 and D1 of relays 1 and 4. Contact A2 of relay 1 is connected to contact B2 of relay 2, and contact C2 of relay 3 is connected to contact D2 of relay 4, and each is connected to the critical power supply circuit through the electromagnetic interference filter 3.

[0008] Furthermore, the input voltage 1 is connected to relays 2, 3, and 5 after passing through electromagnetic interference filter 1 and detection circuit 1 in sequence, and the input voltage 2 is connected to relays 1 and 4 after passing through electromagnetic interference filter 2 and detection circuit 2 in sequence. The electromagnetic interference filter 1 and electromagnetic interference filter 2 can filter the input voltage 1 and input voltage 2 respectively. The electromagnetic interference filter 3 filters the output circuit of the relays. The combination of electromagnetic interference filter 1, electromagnetic interference filter 2, and electromagnetic interference filter 3 filters the entire circuit.

[0009] Furthermore, the output terminals of detection circuit 1 and detection circuit 2 are respectively connected to the input terminals of the dual-input control circuit. Detection circuit 1 detects whether input voltage 1 is a normal input voltage and provides the detection signal 1 to the control circuit; detection circuit 2 detects whether input voltage 2 is a normal input voltage and provides the detection signal 2 to the dual-input control circuit. The output terminals of the dual-input control circuit are respectively connected to the input terminals of drive circuit 1, drive circuit 2 and drive circuit 3. The output terminal of drive circuit 1 is connected to K2 of relay 2, the output terminal of drive circuit 2 is connected to K4 of relay 4, and the output terminal of drive circuit 3 is connected to K5 of relay 5. After receiving detection signal 1 and detection signal 2, the dual-input control circuit determines whether they are normal input voltages and then controls the relay circuit to switch from one of input voltage 1 and input voltage 2 to the other or maintain the current state.

[0010] Furthermore, both input voltage 1 and input voltage 2 can be set by default, with one being the main input and the other being the backup input. When input voltage 1 is set as the main input, input voltage 2 is the backup input, and when input voltage 2 is set as the main input, input voltage 1 is the backup input.

[0011] When both input voltage 1 and input voltage 2 are normal voltages, the main input will be connected to the output of the relay, and the backup input will be isolated from the relay output circuit and the main input voltage due to the disconnection of its corresponding set of contacts.

[0012] When the main input voltage deteriorates, or there is a power outage or over / under voltage, the dual-input control circuit will send a control signal to drive the relay to switch and connect the backup input voltage to the relay output.

[0013] Furthermore, one end of the auxiliary power supply is connected between the electromagnetic interference filter 2 and the detection circuit 2, and the other end is connected to the dual-input control circuit; when the input voltage 1 is an abnormal voltage and the input voltage 2 is a normal input voltage, the auxiliary power supply supplies power to the detection circuit 2 and the dual-input control circuit.

[0014] Furthermore, relays 1, 2, 3, and 4 are all normally open relays, and relay 5 is a double-pole normally closed relay. Input voltage 1 is connected to the normally closed contact of relay 5. When input voltage 1 is normally supplied, it is connected to the critical power supply section. Relay 5 ensures that a power supply circuit is provided to the critical power supply circuit when input voltage 1 is normally supplied. After the critical power supply circuit operates, the drive circuit 3 is sent to disconnect contacts E1 and E2, F1 and F2 of relay 5. Then, the drive circuit 1 is sent to change relays 2 and 3 from the open state to the closed state, connecting input voltage 1 to the critical power supply circuit.

[0015] Furthermore, when input voltage 1 is a normal voltage and input voltage 2 is an abnormal voltage, input voltage 1 is connected to the electromagnetic interference filter 3 via relay 5 to supply power to the critical power circuit. The critical power circuit supplies power to detection circuit 1, detection circuit 2, dual-input control circuit, drive circuit 1, and drive circuit 3. After the dual-input control circuit sends drive 3 to disconnect relay 5, it then sends drive 1 to switch the contacts of relay 2 and relay 3 from open to closed, ensuring that input voltage 1 is connected to the electromagnetic interference filter 3 via relay 2 and relay 3 to supply power to the critical power circuit. At the same time, input voltage 2 is isolated from the relay output and input voltage 1 because its corresponding set of contacts remains open.

[0016] When input voltage 1 is an abnormal voltage and input voltage 2 is a normal input voltage, input voltage 2 is connected to the auxiliary power supply circuit through electromagnetic interference filter 2. The auxiliary power supply powers the detection circuit 2 and the dual-input control circuit. The dual-input control circuit sends drive 3 to switch relay 5 from closed to open, and then sends drive 2 to switch relay 1 and relay 4 from open to closed. Input voltage 2 is connected to the output terminals of relay 1 and relay 4 to power the critical power supply circuit.

[0017] Furthermore, the input voltage 1 and input voltage 2 can be two AC input voltages, one AC input voltage and one DC input voltage, or two DC input voltages.

[0018] Furthermore, the relay may also be a combination of other types of relays and / or other types of contactors and / or power switches.

[0019] Furthermore, the dual-input control circuit is controlled by a microcontroller chip or by a circuit built with analog devices; and the microcontroller chip used in the dual-input control circuit is not limited to sharing a microcontroller chip with the control circuit of the input part of the key power supply unit, but can also use a separate microcontroller chip. Beneficial effects

[0020] The dual-input switching circuit proposed in this invention has the following advantages compared with the prior art:

[0021] This technical solution uses five relays for power switching control, with two relays configured on each power supply. Compared to the previous solution using multiple relays, this simplifies the circuit structure. Compared to contactor solutions, it effectively reduces costs. Furthermore, the two relays per power supply increase the dielectric strength between the two inputs, enhancing circuit safety. It is more suitable for control circuits or low-voltage signals, operating at frequencies of tens to hundreds of times per hour, and is particularly suitable for control signal circuits, small motors, low-power household appliances, lighting, signal lights, solenoid valves, etc. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall circuit of the present invention.

[0023] Figure 2 This is a schematic diagram of the relay status when input voltage 1 is a normal voltage and input voltage 2 is an abnormal voltage.

[0024] Figure 3 This is a schematic diagram of the relay status when input voltage 1 is an abnormal voltage and input voltage 2 is a normal voltage. Detailed Implementation

[0025] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. The described embodiments are merely some embodiments of the present invention, and not all embodiments. Various modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the design concept of the present invention should fall within the protection scope of the present invention. Example

[0026] like Figure 1 As shown, a dual-input switching circuit includes: input voltage 1, input voltage 2, intelligent switching unit, auxiliary power supply unit, and key power supply unit; the intelligent switching unit is connected to input voltage 1, input voltage 2, and auxiliary power supply unit, and connects either input voltage 1 or input voltage 2 to the key power supply unit; the intelligent switching unit includes relay 1, relay 2, relay 3, relay 4, relay 5, dual-input control circuit, and electromagnetic interference filter 3.

[0027] The input voltage 1 passes through the electromagnetic interference filter 1 and the detection circuit 1 in sequence, and is then connected to the normally open contact B1 of the relay 2 and the normally open contact C1 of the relay 3. The input voltage 1 is also connected to the normally closed contacts E1 and F1 of the relay 5 through the electromagnetic interference filter 1.

[0028] The input voltage 2 passes through the electromagnetic interference filter 2 and the detection circuit 2 in sequence, and then connects to the normally open contact A1 of relay 1 and the normally open contact D1 of relay 4.

[0029] Relay 1 contact A2 and relay 2 contact B2 are connected and connected to the critical power circuit through electromagnetic interference filter 3; relay 3 contact C2 and relay 4 contact D2 are connected and connected to the critical power circuit through electromagnetic interference filter 3.

[0030] The electromagnetic interference filter 1 and electromagnetic interference filter 2 can filter input voltage 1 and input voltage 2 respectively; the electromagnetic interference filter 3 filters the output circuit of the relay; the combination of electromagnetic interference filter 1, electromagnetic interference filter 2 and electromagnetic interference filter 3 filters the entire circuit.

[0031] The output terminals of detection circuit 1 and detection circuit 2 are respectively connected to the input terminals of the dual-input control circuit. Detection circuit 1 detects whether input voltage 1 is a normal input voltage and provides the detection signal 1 to the control circuit. Detection circuit 2 detects whether input voltage 2 is a normal input voltage and provides the detection signal 2 to the dual-input control circuit. The output terminals of the dual-input control circuit are respectively connected to the input terminals of drive circuit 1, drive circuit 2 and drive circuit 3. The output terminal of drive circuit 1 is connected to K2 of relay 2, the output terminal of drive circuit 2 is connected to K4 of relay 4, and the output terminal of drive circuit 3 is connected to K5 of relay 5. After receiving detection signal 1 and detection signal 2, the dual-input control circuit determines whether they are normal input voltages and then controls the relay circuit to switch from one of input voltage 1 and input voltage 2 to the other or maintain the current state.

[0032] One end of the auxiliary power supply is connected between the electromagnetic interference filter 2 and the detection circuit 2, and the other end is connected to the dual-input control circuit. When the input voltage 1 is an abnormal voltage and the input voltage 2 is a normal input voltage, the auxiliary power supply supplies power to the detection circuit 2 and the dual-input control circuit.

[0033] Both input voltage 1 and input voltage 2 can be set by default, with one being the main input and the other being the backup input. When input voltage 1 is set as the main input, input voltage 2 is the backup input, and when input voltage 2 is set as the main input, input voltage 1 is the backup input.

[0034] When both input voltage 1 and input voltage 2 are normal voltages, the main input will be connected to the output of the relay, and the backup input will be isolated from the relay output circuit and the main input voltage due to the disconnection of its corresponding set of contacts.

[0035] When the main input voltage deteriorates, or there is a power outage or over / under voltage, the dual-input control circuit will send a control signal to drive the relay to switch and connect the backup input voltage to the relay output.

[0036] Relays 1, 2, 3, and 4 are all normally open relays, and relay 5 is a double-pole normally closed relay. Input voltage 1 is connected to the normally closed contact of relay 5. When input voltage 1 is normally supplied, it is connected to the critical power supply section. Relay 5 ensures that a power supply circuit is provided to the critical power supply circuit when input voltage 1 is normally supplied. After the critical power supply circuit is working, the drive circuit 3 is sent to disconnect contacts E1 and E2, F1 and F2 of relay 5. Then, the drive circuit 1 is sent to change relays 2 and 3 from the open state to the closed state, connecting input voltage 1 to the critical power supply circuit.

[0037] When input voltage 1 is normal and input voltage 2 is abnormal, input voltage 1 is connected to the electromagnetic interference filter 3 via relay 5 to supply power to the critical power circuit. The relay status is as follows: Figure 1 As shown. The critical power supply circuit supplies power to detection circuit 1, detection circuit 2, dual-input control circuit, drive circuit 1, and drive circuit 3. After drive relay 5 is disconnected, the contacts of relays 2 and 3 switch from open to closed, ensuring that input voltage 1 is supplied to the critical power supply circuit via relays 2 and 3 through electromagnetic interference filter 3; simultaneously, input voltage 2 is isolated from the relay output and input voltage 1 because its corresponding set of contacts remains open; the relay states are as follows. Figure 2 As shown.

[0038] When input voltage 1 is an abnormal voltage and input voltage 2 is a normal input voltage, input voltage 2 is connected to the auxiliary power supply circuit via electromagnetic interference filter 2. The auxiliary power supply powers the detection circuit 2 and the dual-input control circuit. The drive circuit 3 switches relay 5 from closed to open, and then the drive circuit 2 switches relays 1 and 4 from open to closed. Input voltage 2 is connected to the output terminals of relays 1 and 4 to power the critical power supply circuit. The relay states are as follows: Figure 3 As shown.

[0039] The relay circuit in this example consists of four normally open relays (relay 1, relay 2, relay 3, and relay 4) and one double-pole normally closed relay (relay 5). It includes four normally open contacts (A1-A2, B1-B2, C1-C2, and D1-D2), two normally closed contacts (E1-E2 and F1-F2), and five coils (K1, K2, K3, K4, and K5). When coils K1, K2, K3, K4, and K5 are not energized, contacts A1-A2, B1-B2, C1-C2, and D1-D2 are open, while contacts E1-E2 and F1-F2 are closed.

[0040] The relay used in this embodiment is a PCB board soldering type. This product has the advantages of small size, light weight, low coil drive power, and low vibration during operation, making it particularly suitable for use in integrated PCB main circuits.

[0041] Input voltage 1 and input voltage 2 can be two AC input voltages, one AC input voltage and one DC input voltage, or two DC input voltages.

[0042] The relay can also be a combination of other types of relays or / and other types of contactors or / and power switches.

[0043] The dual-input control circuit is controlled by a microcontroller chip or by a circuit built with analog devices. The microcontroller chip used in the dual-input control circuit is not limited to sharing a microcontroller chip with the control circuit of the input part of the key power supply unit; a separate microcontroller chip can also be used.

Claims

1. A dual-input switching circuit, comprising: The system comprises an input voltage 1, an input voltage 2, an intelligent switching unit, an auxiliary power supply unit, and a critical power supply unit. The intelligent switching unit is connected to the input voltage 1, the input voltage 2, and the auxiliary power supply unit, and connects either the input voltage 1 or the input voltage 2 to the critical power supply unit. The intelligent switching unit includes a relay group, a dual-input control circuit, and an electromagnetic interference filter 3. Input voltage 1 is connected to the normally open contacts B1 and C1 of relays 2 and 3, and to the normally closed contacts E1 and F1 of relay 5. Input voltage 2 is connected to the normally open contacts A1 and D1 of relays 1 and 4. Contact A2 of relay 1 is connected to contact B2 of relay 2, and contact C2 of relay 3 is connected to contact D2 of relay 4, and each is connected to the critical power supply circuit via the electromagnetic interference filter 3.

2. A dual input switching circuit according to claim 1, characterized in that: The input voltage 1 passes through the electromagnetic interference filter 1 and the detection circuit 1 in sequence and is then connected to relays 2, 3, and 5. The input voltage 2 passes through the electromagnetic interference filter 2 and the detection circuit 2 in sequence and is then connected to relays 1 and 4. The electromagnetic interference filter 1 and the electromagnetic interference filter 2 can filter the input voltage 1 and the input voltage 2 respectively. The electromagnetic interference filter 3 filters the output circuit of the relays. The combination of electromagnetic interference filter 1, electromagnetic interference filter 2, and electromagnetic interference filter 3 filters the entire circuit.

3. A dual input switching circuit according to claim 2, characterized in that: The output terminals of detection circuit 1 and detection circuit 2 are respectively connected to the input terminals of the dual-input control circuit. Detection circuit 1 detects whether the input voltage 1 is a normal input voltage and provides the detection signal 1 to the control circuit. The detection circuit 2 detects whether the input voltage 2 is a normal input voltage and provides the detection signal 2 to the dual-input control circuit. The output of the dual-input control circuit is connected to the input of the drive circuit 1, drive circuit 2 and drive circuit 3 respectively. The output of drive circuit 1 is connected to K2 of relay 2, the output of drive circuit 2 is connected to K4 of relay 4, and the output of drive circuit 3 is connected to K5 of relay 5. After receiving the detection signal 1 and the detection signal 2, the dual-input control circuit determines whether they are normal input voltages and then controls the relay circuit to switch from one of the input voltages 1 and 2 to the other or keep the current state unchanged.

4. The dual input switching circuit of claim 1, wherein: Both input voltage 1 and input voltage 2 can be set by default, with one being the main input and the other being the backup input. When input voltage 1 is set as the main input, input voltage 2 is the backup input, and when input voltage 2 is set as the main input, input voltage 1 is the backup input. When both input voltage 1 and input voltage 2 are normal voltages, the main input will be connected to the output of the relay, and the backup input will be isolated from the relay output circuit and the main input voltage due to the disconnection of its corresponding set of contacts. When the main input voltage deteriorates, or there is a power outage or over / under voltage, the dual-input control circuit will send a control signal to drive the relay to switch and connect the backup input voltage to the relay output.

5. The dual input switching circuit of claim 1, wherein: One end of the auxiliary power supply is connected between the electromagnetic interference filter 2 and the detection circuit 2, and the other end is connected to the dual-input control circuit. When the input voltage 1 is an abnormal voltage and the input voltage 2 is a normal input voltage, the auxiliary power supply supplies power to the detection circuit 2 and the dual-input control circuit.

6. A dual input switching circuit according to claim 1, characterized in that: Relays 1, 2, 3, and 4 are all normally open relays, and relay 5 is a double-pole normally closed relay. Input voltage 1 is connected to the normally closed contact of relay 5. When input voltage 1 is normally supplied, it is connected to the critical power supply section. Relay 5 ensures that a power supply circuit is provided to the critical power supply circuit when input voltage 1 is normally supplied. After the critical power supply circuit is working, the drive circuit 3 is sent to disconnect contacts E1 and E2, F1 and F2 of relay 5. Then, the drive circuit 1 is sent to change relays 2 and 3 from the open state to the closed state, connecting input voltage 1 to the critical power supply circuit.

7. A dual input switching circuit according to claim 6, characterised in that: When input voltage 1 is a normal voltage and input voltage 2 is an abnormal voltage, input voltage 1 is connected to the electromagnetic interference filter 3 through relay 5 to supply power to the critical power circuit. The critical power circuit supplies power to detection circuit 1, detection circuit 2, dual-input control circuit, drive circuit 1, and drive circuit 3. The dual-input control circuit sends drive 3 to disconnect relay 5, and then sends drive 1 to switch the contacts of relay 2 and relay 3 from open to closed, ensuring that input voltage 1 is connected to the electromagnetic interference filter 3 through relay 2 and relay 3 to supply power to the critical power circuit. At the same time, input voltage 2 will be isolated from the relay output and input voltage 1 because its corresponding set of contacts remains open. When input voltage 1 is an abnormal voltage and input voltage 2 is a normal input voltage, input voltage 2 is connected to the auxiliary power supply circuit through electromagnetic interference filter 2. The auxiliary power supply powers the detection circuit 2 and the dual-input control circuit. The dual-input control circuit sends a drive 3 to switch the relay 5 from closed to open, and then sends a drive 2 to switch the relays 1 and 4 from open to closed. The input voltage 2 is connected to the output terminals of the relays 1 and 4 to power the critical power circuit.

8. The dual input switching circuit of claim 1, wherein: The input voltage 1 and input voltage 2 are two AC input voltages, or one AC input voltage and one DC input voltage, or two DC input voltages.

9. A dual input switching circuit according to claim 1, characterized in that: The dual-input control circuit is controlled by a microcontroller chip or by a circuit built with analog devices; and the microcontroller chip used in the dual-input control circuit is not limited to sharing a microcontroller chip with the control circuit of the input part of the key power supply unit, or using a separate microcontroller chip.

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