Uninterruptible power supply

Abstract

The embodiments of the present application relate to the technical field of power electronics. Disclosed is an uninterruptible power supply, which solves the problem of how to ensure the continuity of power supply to a load end while protecting a switch device located on a line from damage during the switching between a main circuit and a bypass. The specific solution is: an uninterruptible power supply device comprising a main circuit, a bypass and a load end, wherein both the main circuit and the bypass are configured to supply power to the load end; an inverter circuit and a switch are provided on the main circuit, an output end of the inverter circuit is connected to the switch, and the switch is configured to control the connection or disconnection between the output end of the inverter circuit and the load end; and a bidirectional conduction device is connected in series to a fuse, the bidirectional conduction device and the fuse, which are connected in series, are connected in parallel to the switch, the fuse is configured to open when a fault current flows through the bidirectional conduction device and the fault current is greater than a first current threshold, and the bidirectional conduction device is configured to be turned on during the switching from supplying power to the load end by the bypass to supplying power to the load end by the main circuit.

Description

An uninterruptible power supply

[0001] The present application claims priority to the Chinese patent application No. 202421739002.8, filed on July 22, 2024, and entitled "An uninterruptible power supply", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application relates to the field of power electronics, in particular to an uninterruptible power supply. BACKGROUND

[0003] An uninterruptible power supply (UPS) includes a main circuit, a bypass circuit and a load end, and the main circuit and the bypass circuit are used to supply power to the load end. The main circuit is provided with an inverter circuit and a relay, and the relay is used to disconnect the output end of the inverter circuit from the load end when the main circuit is abnormal, and control the inverter circuit to be disconnected. At this time, the bypass circuit is used to supply power to the load end. The relay is also used to close the output end of the inverter circuit from the load end when the main circuit returns to normal, and control the inverter circuit to be turned on. At this time, the main circuit is used to supply power to the load end.

[0004] However, there is a mechanical action delay when the relay is closed or disconnected. In addition, the fault current on the main circuit can also cause damage to the switching device. Therefore, during the switching process of the main circuit and the bypass circuit, how to ensure the continuity of power supply to the load end while protecting the switching device on the line from damage becomes a problem to be solved.

[0005] Utility model content

[0006] The embodiments of the present application provide an uninterruptible power supply, which solves the problem of how to ensure the continuity of power supply to the load end while protecting the switching device on the line from damage during the switching process of the main circuit and the bypass circuit.

[0007] To achieve the above-mentioned purpose, the embodiments of the present application adopt the following technical solutions:

[0008] In a first aspect, the present application provides an uninterruptible power supply, which includes a main circuit, a bypass circuit and a load end, and the main circuit and the bypass circuit are used to supply power to the load end. The main circuit is provided with an inverter circuit and a switch, and the output end of the inverter circuit is connected to the switch. The switch is used to control the inverter circuit to be turned on or disconnected between the output end and the load end. A bidirectional conduction device is connected in series with a fuse, and the series-connected bidirectional conduction device and the fuse are connected in parallel with the switch. The fuse is used to be disconnected when a fault current flows through the bidirectional conduction device and the fault current is greater than a first current threshold. The bidirectional conduction device is used to be turned on when the power supply to the load end by the bypass circuit is switched to the power supply to the load end by the main circuit.

[0009] In a possible embodiment, the ampere square second of the fuse is less than the explosion ampere square second of the bidirectional conducting device, which refers to the ampere square second when the bidirectional conducting device is about to explode, and can be determined by experimental test.

[0010] According to the scheme, the bidirectional conducting device in parallel with the switch is provided, and the bidirectional conducting device is used to conduct when the power supply for the load end is switched from the bypass to the main circuit. Compared with the switching speed of the switch, the switching speed of the bidirectional conducting device is faster, so that the rapid switching of the bypass and the main circuit can be realized, and the continuity of the power supply for the load end can be ensured. Meanwhile, the fuse in series with the bidirectional conducting device is provided, and the fuse is used to be disconnected when the fault current flows through the bidirectional conducting device and the fault current is greater than the first current threshold, so that the explosion damage of the bidirectional conducting device can be avoided when the uninterruptible power supply fails, and the reliability of the uninterruptible power supply can be improved.

[0011] In combination with the first aspect, in a possible implementation, the fuse in series with the bidirectional conducting device is a first fuse, and the switch is in series with a second fuse, and the second fuse is used to be disconnected when the current flowing through the switch is greater than a second current threshold, and the second current threshold is greater than the first current threshold.

[0012] According to the scheme, the second fuse in series with the switch is provided, and the second fuse is used to be disconnected when the current flowing through the switch is greater than the second current threshold, so that the overcurrent protection of the switch is realized, and the switch can be prevented from being damaged when the uninterruptible power supply fails, and the reliability of the uninterruptible power supply can be improved.

[0013] In combination with the first aspect, in a possible implementation, the bidirectional conducting device includes two thyristors, the fuse in series with the bidirectional conducting device is a first fuse, and the two thyristors are connected in reverse parallel and in series with the first fuse.

[0014] In a possible embodiment, the ampere square second of the first fuse is less than the explosion ampere square second of any one of the two thyristors.

[0015] According to the scheme, the two thyristors in the bidirectional conducting device are protected by the first fuse, so that the explosion damage of the two thyristors can be avoided when the uninterruptible power supply fails, and the reliability of the uninterruptible power supply can be improved.

[0016] In combination with the first aspect, in a possible implementation, the fusing of the first fuse is used to protect the bidirectional conducting device.

[0017] In combination with the first aspect, in a possible implementation, the fusing of the second fuse is used to protect the switch.

[0018] In a possible implementation of the first aspect, the bidirectional conducting device includes two thyristors, and the fuse connected in series with the bidirectional conducting device includes two fuses, and the two thyristors are connected in reverse parallel after being connected in series with one of the fuses respectively.

[0019] In a possible embodiment, the ampere square second of each of the two fuses is less than the explosion ampere square second of the thyristor connected in series with the fuse respectively, and the explosion ampere square second of each thyristor refers to the ampere square second when the thyristor is about to explode, which can be determined by experiment.

[0020] Based on the scheme, the bidirectional conducting device includes two thyristors, and the fuse connected in series with the bidirectional conducting device includes two fuses, and the two thyristors are connected in reverse parallel after being connected in series with one of the fuses respectively, so that the two thyristors can be prevented from exploding and being damaged when the uninterruptible power supply fails, and the reliability of the uninterruptible power supply can be improved.

[0021] In a possible implementation of the first aspect, the direction of the fault current is opposite to the direction of the output current of the output end of the inverter circuit.

[0022] Based on the scheme, by setting the fuse connected in series with the bidirectional conducting device, the fuse is used to be disconnected when the fault current flows through the bidirectional conducting device and the fault current is greater than the first current threshold, so that the bidirectional conducting device can be prevented from exploding and being damaged when the uninterruptible power supply fails and the direction of the fault current is opposite to the direction of the output current of the output end of the inverter circuit, and the reliability of the uninterruptible power supply can be improved.

[0023] In a possible implementation of the first aspect, the fuse includes a plurality of sub-fuses connected in parallel.

[0024] Based on the scheme, by using a plurality of sub-fuses connected in parallel to replace one fuse, the plurality of sub-fuses share the current compared with using one fuse, so that the life of each sub-fuse in the plurality of sub-fuses can be prolonged. BRIEF DESCRIPTION OF DRAWINGS

[0025] FIG. 1 is a circuit topology schematic diagram of a modular UPS;

[0026] FIG. 2 is a circuit topology schematic diagram of another modular UPS;

[0027] FIG. 3 is a circuit topology schematic diagram of still another modular UPS;

[0028] FIG. 4 is a circuit topology schematic diagram of an application scenario of an uninterruptible power supply provided by an embodiment of the present application;

[0029] FIG. 5 is a schematic diagram of a circuit topology of an uninterruptible power supply according to an embodiment of the present application;

[0030] FIG. 6 is a schematic diagram of a circuit topology of an uninterruptible power supply according to another embodiment of the present application;

[0031] FIG. 7 is a schematic diagram of a circuit topology of an uninterruptible power supply according to yet another embodiment of the present application;

[0032] FIG. 8 is a schematic diagram of a circuit topology of an uninterruptible power supply according to still another embodiment of the present application;

[0033] FIG. 9 is a schematic diagram of a circuit topology of an uninterruptible power supply according to still another embodiment of the present application;

[0034] FIG. 10 is a schematic diagram of a circuit topology of an uninterruptible power supply according to still another embodiment of the present application;

[0035] FIG. 11 is a schematic diagram of a circuit topology of an uninterruptible power supply according to still another embodiment of the present application;

[0036] FIG. 12 is a schematic diagram of a circuit topology of an uninterruptible power supply according to still another embodiment of the present application. DETAILED DESCRIPTION

[0037] The making and using of various embodiments are discussed in detail below. It should be appreciated that the specific embodiments discussed are merely illustrative of specific ways to make and use the application and this application should not be construed as limited to such specific embodiments. Rather, these specific embodiments are presented so that this application will be thorough and complete, and will fully convey the scope thereof to those skilled in the art.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0039] Circuits or other components can be described as or said to be "configured to" perform one or more tasks for convenience. In this context, "configured to" is used to connote structure by indicating that the circuits / components include structure (e.g., circuitry) that performs the task during operation. As such, the term "configured to" can or can not connote structure in a way that is accessible by a human being, and in fact in a typical case will not connote structure accessible by a human being. The structure may, in some

[0040] The technical solutions in the embodiments of this application will be described below with reference to the accompanying drawings. In this application, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, or B exists alone, where A and B can be singular or plural. The character " / " generally indicates that the related objects before and after are in an "or" relationship. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can mean: a, b, c, a and b, a and c, b and c, or a, b, and c, where a, b, and c can be single or multiple. In addition, in the embodiments of this application, the words "first," "second," etc., do not limit the quantity or order.

[0041] In this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or illustration. Any embodiment or design described as "exemplary" or "for example" in this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of the terms "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0042] Before introducing the embodiments of this application, the technical terms and background technology involved in this application will be introduced first.

[0043] A silicon controlled rectifier (SCR) is a type of thyristor used as a switch in circuits. It offers advantages such as small size, high efficiency, and long lifespan. Types of SCRs include unidirectional SCRs and triple alternating current semiconductor switches (Triacs). Triacs, also known as bidirectional SCRs, can replace two unidirectional SCRs connected in parallel with opposite polarities (or two unidirectional SCRs connected in reverse parallel).

[0044] Figure 1 shows a circuit topology diagram of a modular UPS 100. The modular UPS 100 includes a bypass 110, a load terminal H, and multiple main circuits 120. The bypass 110 can also be called a bypass module or bypass device, and the main circuits 120 can also be called power modules or power conversion devices. The input terminal of the bypass 110 and the first input terminals of the multiple main circuits 120 are used to connect to the input power supply 200, the second input terminals of the multiple main circuits 120 are used to connect to the energy storage device 400, and the output terminals of the bypass 110 and the multiple main circuits 120 are connected to the load terminal H, which is used to connect to the load 300.

[0045] Referring to Figure 1, each main circuit 120 includes a rectifier circuit 121 (also called a rectifier), a DC-DC converter circuit 122 (also called a battery discharger), and an inverter circuit 123 (also called an inverter). The input terminal of the rectifier circuit 121 is the first input terminal of the main circuit 120 and is used to connect to the input power supply 200. The input terminal of the DC-DC converter circuit 122 is the second input terminal of the main circuit 120 and is used to connect to the energy storage device 400. The output terminals of the rectifier circuit 121 and the DC-DC converter circuit 122 are connected to the input terminal of the inverter circuit 123. The output terminal of the inverter circuit 123 is the output terminal of the main circuit 120 and is used to connect to the load terminal H.

[0046] When the input power supply 200 is normal, the rectifier circuit 121 in the main circuit 120 is used to convert the AC power provided by the input power supply 200 into a stable DC voltage, and the inverter circuit 123 is used to convert the stable DC voltage into a stable AC voltage so as to provide power to the load 300 through the load terminal H.

[0047] When the input power supply 200 is abnormal, the DC-DC converter circuit 122 in the main circuit 120 is used to convert the DC voltage provided by the energy storage device 400 into a stable DC voltage, and the inverter circuit 123 is used to convert the stable DC voltage into a stable AC voltage to provide power to the load 300 through the load terminal H.

[0048] When the input power supply 200 is normal, but all the main circuits 120 in the modular UPS100 fail, the bypass 110 is used to transmit the AC power provided by the input power supply 200 to the load 300, so as to provide power to the load 300 through the load terminal H and ensure the continuity of power supply to the load 300.

[0049] Referring to Figure 1, each main circuit 120 also includes a relay 124 and a fuse 125 corresponding to each phase output terminal of the inverter circuit 123. The first terminal of the relay 124 is connected to one phase output terminal of the inverter circuit 123, and the second terminal of the relay 124 is connected to the first terminal of the fuse 125. The second terminal of the fuse 125 is used to connect to the load 300. Therefore, when a fault occurs in the main circuit 120, the relay 124 can isolate the main circuit 120, and the fuse 125 provides overcurrent protection for the relay 124, thereby improving the reliability of the main circuit 120.

[0050] However, there is a mechanical delay when the relay 124 is closed or opened, and the power supply continuity of the load 300 cannot be guaranteed during the switching process between the bypass 110 and the main circuit 120.

[0051] To solve this problem, referring to Figure 1, each main circuit 120 also includes a first unidirectional SCR 126 and a second unidirectional SCR 127 corresponding to each phase output terminal of the inverter circuit 123. The cathode of the first unidirectional SCR 126 and the anode of the second unidirectional SCR 127 are connected to the first terminal of the relay 124, and the anode of the first unidirectional SCR 126 and the cathode of the second unidirectional SCR 127 are connected to the second terminal of the relay 124.

[0052] During the switching process between bypass 110 and main circuit 120, the first unidirectional SCR 126 and the second unidirectional SCR 127 are first turned on, and the relay 124 is closed at the same time. After the relay 124 is closed, the first unidirectional SCR 126 and the second unidirectional SCR 127 are then turned off. Compared with the switching speed of the relay 124, the switching speed of the first unidirectional SCR 126 and the second unidirectional SCR 127 is faster, thus enabling rapid switching between bypass 110 and main circuit 120 and ensuring the power supply continuity of the 300 load.

[0053] Understandably, during the operation of the main circuit 120, relay 124 and fuse 125 continuously carry a large current, while the first unidirectional SCR 126 and the second unidirectional SCR 127 do not continuously carry a large current; the current flowing through the first unidirectional SCR 126 and the second unidirectional SCR 127 is relatively small. In this main circuit 120, fuse 125 is matched with relay 124. When the modular UPS 100 fails, and the fault current flows through fuse 125 and relay 124, fuse 125 can quickly trip, thus protecting relay 124.

[0054] However, the fuse 125 is incompatible with either the first unidirectional SCR 126 or the second unidirectional SCR 127. When the modular UPS 100 fails and a large current flows through the first unidirectional SCR 126, the second unidirectional SCR 127, and the fuse 125, the fuse 125 cannot provide overcurrent protection for the first unidirectional SCR 126 or the second unidirectional SCR 127. The first unidirectional SCR 126 or the second unidirectional SCR 127 will explode and be damaged, resulting in low reliability of the main circuit 120.

[0055] For example, as shown in Figure 2, when the fault point is located between the modular UPS100 and the load 300, such as when the output cable of the modular UPS100 is damaged and short-circuits with the casing of the modular UPS100, the current flowing through the first unidirectional SCR 126 and the second unidirectional SCR 127 will flow as shown by line A in Figure 2. This current will cause the first unidirectional SCR 126 or the second unidirectional SCR 127 to explode and be damaged.

[0056] To address this issue, when the fault point is outside the main circuit 120, such as when the output cable of the aforementioned modular UPS 100 is damaged and short-circuited, the current limiting protection function of the inverter circuit 123 can be used to limit the current flowing through the first unidirectional SCR 126 and the second unidirectional SCR 127, thereby preventing damage to the first unidirectional SCR 126 and the second unidirectional SCR 127.

[0057] However, as shown in Figure 3, when the fault point is inside the main circuit 120, for example, when the inverter circuit 123 is short-circuited, and the current output from the other main circuits 120 is input in reverse to the faulty main circuit 120, the current flow through the first unidirectional SCR 126 and the second unidirectional SCR 127 is as shown by line B in Figure 3. The inverter circuit 123 in the faulty main circuit 120 cannot perform current limiting protection, and at the same time, the inverter circuits 123 in the other main circuits 120 also cannot perform current limiting protection. The fuse 125 also cannot protect the first unidirectional SCR 126 and the second unidirectional SCR 127, which will cause the first unidirectional SCR 126 or the second unidirectional SCR 127 to explode and be damaged, resulting in low reliability of the faulty main circuit 120.

[0058] In summary, in the modular UPS100, the relay 124 experiences a mechanical delay when closing and opening. Furthermore, fault current on the main circuit 120 can cause the first unidirectional SCR 126 or the second unidirectional SCR 127 to explode and be damaged. Therefore, ensuring the continuity of power supply to the load H while protecting the first unidirectional SCR 126 or the second unidirectional SCR 127 from damage during the switching between the bypass 110 and the main circuit 120 is a pressing issue. Based on this, this application provides an uninterruptible power supply that uses a fuse connected in series with a bidirectional conducting device to provide overcurrent protection, preventing the bidirectional conducting device from exploding. The series-connected bidirectional conducting device and fuse are connected in parallel with the switch, ensuring the continuity of power supply to the load during the switching between the main circuit and the bypass circuit, thus improving the reliability of the uninterruptible power supply.

[0059] Figure 4 shows a circuit topology diagram of an uninterruptible power supply (UPS) 500 application scenario provided in an embodiment of this application. Specifically, the UPS 500 may include a bypass 510, a load terminal H, and at least one main circuit 520. Both the bypass 510 and the at least one main circuit 520 are used to supply power to the load terminal H. The bypass 510 may also be called a bypass module or bypass device, and the main circuit 520 may also be called a power module or power conversion device. This application embodiment does not limit the specific number of main circuits 520 included in the UPS 500. In the following embodiments of this application, the UPS 500 includes one main circuit 520 as an example for illustrative purposes. The input terminal of bypass 510 and the first input terminal of at least one main circuit 520 are connected to the first input terminal of uninterruptible power supply 500, the second input terminal of at least one main circuit 520 is connected to the second input terminal of uninterruptible power supply 500, the output terminal of bypass 510 and the output terminal of at least one main circuit 520 are connected to the load terminal H, the first input terminal of uninterruptible power supply 500 is used to connect to input power supply 200, the second input terminal of uninterruptible power supply 500 is used to connect to energy storage device 400, and the load terminal H is used to connect to load 300.

[0060] The uninterruptible power supply 500 can be applied to systems such as large data centers, large communication centers, large enterprise computer rooms, financial system computer rooms, industrial automation centers and dispatch centers. The specific systems in which the uninterruptible power supply 500 is applied are not limited in the embodiments of this application.

[0061] In one possible embodiment, when the uninterruptible power supply 500 is applied to the above system, it can be applied to the system as a standalone unit, where a single uninterruptible power supply 500 is applied to the system. Alternatively, multiple uninterruptible power supplies 500 can be applied to the system in parallel, where multiple uninterruptible power supplies 500 are connected in parallel and then applied to the system. This application embodiment does not limit this. As shown in FIG4, this application embodiment takes the application of an uninterruptible power supply 500 as a standalone unit in the above system as an example for illustrative explanation.

[0062] Referring to Figure 4, the first input terminal of the uninterruptible power supply 500 is connected to the input power supply 200 via the input distribution cabinet 600. The input power supply 200 may include mains power 210 or a fuel generator set 220. The second input terminal of the uninterruptible power supply 500 is connected to the energy storage device 400 via the battery combiner box 700. The energy storage device 400 may include battery packs 1 to N. The N battery packs may be connected in series, in parallel, or a portion of them may be connected in series and the rest in parallel. N is a positive integer greater than or equal to 1. The load terminal H of the uninterruptible power supply 500 is connected to the load 300 via the output distribution cabinet 800. The load 300 may include multiple loads. The uninterruptible power supply 500 is also connected to the management system 900 via a communication cable. The management system 900 is used to manage and control the uninterruptible power supply 500. The management system 900 can also manage and control the input distribution cabinet 600, battery combiner box 700, energy storage device 400 and output distribution cabinet 800 via the communication cables between the uninterruptible power supply 500 and other devices.

[0063] In one possible embodiment, when the uninterruptible power supply 500 is applied to the above system, it can be installed against a wall or not, and this application embodiment does not limit this.

[0064] Figure 5 shows a circuit topology diagram of an uninterruptible power supply 500 provided in an embodiment of this application. The uninterruptible power supply 500 includes a bypass 510, a load terminal H, and a main circuit 520. The main circuit 520 is equipped with an inverter circuit 521 and a switch K. The output terminal of the inverter circuit 521 is connected to the switch K, which controls the connection or disconnection between the output terminal of the inverter circuit 521 and the load terminal H. A bidirectional conducting device 522 is connected in series with a fuse 523, and the series-connected bidirectional conducting device 522 and fuse 523 are connected in parallel with the switch K. The fuse 523 is used to disconnect when a fault current flows through the bidirectional conducting device 522 and the fault current exceeds a first current threshold. This embodiment of the application does not limit the specific value of the first current threshold. The bidirectional conducting device 522 is used to conduct when the power supply to the load terminal H is switched from the bypass 510 to the main circuit 520.

[0065] Optionally, the type of switch K may include a relay or a contactor. This application embodiment does not limit the specific type of switch K.

[0066] Optionally, the bidirectional conducting device 522 includes a bidirectional thyristor, or the bidirectional conducting device 522 includes two unidirectional thyristors connected in reverse parallel. This application embodiment does not limit this, for example, Figure 5 uses the bidirectional conducting device 522 including a bidirectional thyristor TRIAC as an example for illustrative purposes.

[0067] Optionally, the type of fuse 523 may include a fuse or a fast-acting fuse. This application embodiment does not limit this. For example, Figure 5 shows an example where fuse 523 includes a first fuse FU1.

[0068] Compared to the modular UPS100 shown in Figure 1, the main circuit 520 of this uninterruptible power supply 500 incorporates a bidirectional conducting device 522 connected in parallel with switch K. This device 522 conducts when the power supply to load H switches from bypass 510 to main circuit 520. Compared to the switching speed of switch K, the bidirectional conducting device 522 switches much faster, enabling rapid switching between bypass 510 and main circuit 520 and ensuring continuous power supply to load H. Compared to the modular UPS100 shown in Figure 2, the main circuit 520 of this uninterruptible power supply 500 incorporates a fuse 523 connected in series with the bidirectional conducting device 522. This fuse 523 disconnects when a fault current flows through the bidirectional conducting device 522 and exceeds a first current threshold. This prevents the bidirectional conducting device 522 from exploding and being damaged in the event of a fault in the uninterruptible power supply 500, thus improving the reliability of the uninterruptible power supply 500.

[0069] In one possible embodiment, the direction of the fault current is opposite to the direction of the output current at the output terminal of the inverter circuit 521. In the main circuit 520 of the uninterruptible power supply 500, a fuse 523 connected in series with the bidirectional conducting device 522 is provided. The fuse 523 is used to disconnect when the fault current flows through the bidirectional conducting device 522 and the fault current is greater than a first current threshold. This can prevent the bidirectional conducting device 522 from exploding and being damaged when the uninterruptible power supply 500 fails and the direction of the fault current is opposite to the direction of the output current at the output terminal of the inverter circuit 521, thereby improving the reliability of the uninterruptible power supply 500.

[0070] In one possible embodiment, referring to FIG5, the main circuit 520 further includes a rectifier circuit 524 (also referred to as a rectifier) ​​and a DC-DC converter circuit 525 (also referred to as a battery discharger). The input terminal of the rectifier circuit 524 is used to connect to the input power supply 200, the input terminal of the DC-DC converter circuit 525 is used to connect to the energy storage device 400, and the output terminals of the rectifier circuit 524 and the DC-DC converter circuit 525 are connected to the input terminal of the inverter circuit 521.

[0071] Optionally, the inverter circuit 521 may include a single-phase output terminal or a three-phase output terminal. This application embodiment does not limit this. When the inverter circuit 521 includes a single-phase output terminal, the circuit topology diagram of the uninterruptible power supply 500 is shown in Figure 5. When the inverter circuit 521 includes a three-phase output terminal, the circuit topology diagram of the uninterruptible power supply 500 is shown in Figure 6. Referring to Figure 6, when the inverter circuit 521 includes a three-phase output terminal, the main circuit 520 also includes a bidirectional conducting device 522, a switch K, and a fuse 523 respectively connected to each phase output terminal of the inverter circuit 521. In the following embodiments of this application, the inverter circuit 521 including a single-phase output terminal is used as an example for illustrative explanation.

[0072] In one possible embodiment, when the inverter circuit 521 includes a single-phase output terminal, the uninterruptible power supply 500 can be referred to as a single-phase uninterruptible power supply, and when the inverter circuit 521 includes a three-phase output terminal, the uninterruptible power supply 500 can be referred to as a three-phase uninterruptible power supply.

[0073] In one possible embodiment, fuse 523 includes a plurality of sub-fuses connected in parallel. By using the plurality of sub-fuses connected in parallel to equivalently replace a single fuse, the plurality of sub-fuses connected in parallel share the current compared to using a single fuse, thereby extending the life of each of the plurality of sub-fuses.

[0074] The following section introduces various possible circuit topologies for the Uninterruptible Power Supply 500:

[0075] In one possible embodiment, referring to FIG5, the bidirectional conducting device 522 includes a bidirectional thyristor TRIAC, and the fuse 523 includes a first fuse FU1, which is matched with the bidirectional thyristor TRIAC. When a fault occurs in the main circuit 520, and a fault current flows through the bidirectional thyristor TRIAC and the first fuse FU1, the first fuse FU1 melts in time, providing overcurrent protection for the bidirectional thyristor TRIAC. This can prevent the bidirectional thyristor TRIAC from exploding and being damaged, thereby improving the reliability of the uninterruptible power supply 500.

[0076] In one possible embodiment, the first fuse FU1 is matched with a bidirectional thyristor TRIAC, meaning that the first fuse FU1's ampere-square-second (I0.05) is...2 t) is less than the explosion ampere-square seconds of the bidirectional thyristor TRIAC. The explosion ampere-square seconds of the bidirectional thyristor TRIAC refers to the ampere-square seconds when the bidirectional thyristor TRIAC is about to explode, which can be determined by experimental testing.

[0077] In one possible embodiment, as shown in FIG7, the bidirectional conducting device 522 includes a first unidirectional thyristor 5221 (also referred to as a thyristor) and a second unidirectional thyristor 5222 connected in reverse parallel. The fuse 523 includes a first fuse FU1, which is matched with the first unidirectional thyristor 5221 and the second unidirectional thyristor 5222. When a fault occurs in the main circuit 520, and a fault current flows through the first fuse FU1, the first unidirectional thyristor 5221, and the second unidirectional thyristor 5222, the first fuse FU1 melts in time, providing overcurrent protection for the first unidirectional thyristor 5221 and the second unidirectional thyristor 5222. This can prevent the first unidirectional thyristor 5221 and the second unidirectional thyristor 5222 from exploding and being damaged, thereby improving the reliability of the uninterruptible power supply 500.

[0078] In one possible embodiment, the first fuse FU1 is matched with the first unidirectional thyristor 5221 and the second unidirectional thyristor 5222, meaning that the ampere-second square of the first fuse FU1 is less than the explosive ampere-second square of the first unidirectional thyristor 5221, and the ampere-second square of the first fuse FU1 is less than the explosive ampere-second square of the second unidirectional thyristor 5222.

[0079] In one possible embodiment, as shown in Figure 8, the bidirectional conducting device 522 includes a first unidirectional thyristor 5221 and a second unidirectional thyristor 5222. The fuse 523 includes two fuses. The first unidirectional thyristor 5221 and the second unidirectional thyristor 5222 are connected in series with one of the fuses and then connected in reverse parallel. The two fuses include a second fuse FU2 and a third fuse FU3. The second fuse FU2 is matched with the first unidirectional thyristor 5221, and the third fuse FU3 is matched with the second unidirectional thyristor 5222. When the uninterruptible power supply 500 fails and a fault current flows through the first unidirectional thyristor 5221 and the second fuse FU2, the second fuse FU2 melts in time, providing overcurrent protection for the first unidirectional thyristor 5221. This can prevent the first unidirectional thyristor 5221 from exploding and being damaged, thereby improving the reliability of the uninterruptible power supply 500. When the uninterruptible power supply 500 fails, and the fault current flows through the second unidirectional thyristor 5222 and the third fuse FU3, the third fuse FU3 melts in time, providing overcurrent protection for the second unidirectional thyristor 5222. This can prevent the second unidirectional thyristor 5222 from exploding and being damaged, and can improve the reliability of the uninterruptible power supply 500.

[0080] In one possible embodiment, the second fuse FU2 is matched with the first unidirectional thyristor 5221, and the third fuse FU3 is matched with the second unidirectional thyristor 5222. This means that the ampere-second square of the second fuse FU2 is less than the explosive ampere-second square of the first unidirectional thyristor 5221, and the ampere-second square of the third fuse FU3 is less than the explosive ampere-second square of the second unidirectional thyristor 5222.

[0081] The uninterruptible power supply 500 provided in this application embodiment incorporates a bidirectional conducting device 522 connected in parallel with switch K. This bidirectional conducting device 522 is used to conduct when switching from power supply to load terminal H via bypass 510 to power supply to load terminal H via main circuit 520. Compared to the switching speed of switch K, the bidirectional conducting device 522 has a faster switching speed, thereby enabling rapid switching between bypass 510 and main circuit 520 and ensuring the continuity of power supply to load terminal H. Furthermore, a fuse 523 is connected in series with the bidirectional conducting device 522. This fuse 523 is used to disconnect when a fault current flows through the bidirectional conducting device 522 and the fault current exceeds a first current threshold. This prevents the bidirectional conducting device 522 from exploding and being damaged when the uninterruptible power supply 500 fails, thus improving the reliability of the uninterruptible power supply 500.

[0082] In one possible embodiment, referring to Figure 5 and as shown in Figure 9, the fuse 523 connected in series with the bidirectional conducting device 522 is the first fuse, and the fuse 526 connected in series with the switch K is the second fuse. The fuse 526 is used to disconnect when the current flowing through the switch K is greater than a second current threshold, which is greater than the first current threshold. This embodiment does not limit the specific value of the second current threshold. The melting of fuse 523 (the first fuse) protects the bidirectional conducting device 522, and the melting of fuse 526 (the second fuse) protects the switch K.

[0083] In one possible embodiment, as shown in FIG9, the fuse 526 includes a fourth fuse FU4 that is matched with the switch K and is used to provide overcurrent protection for the switch K.

[0084] Optionally, referring to Figure 9, the fourth fuse FU4 can be disposed between connection point M and load terminal H, or it can be disposed between switch K and connection point M. This application embodiment does not limit this, and the following provides an exemplary description of possible circuit topologies:

[0085] In one possible embodiment, referring to FIG5, when the fuse 526 is located between the connection point M and the load terminal H, the circuit topology of the uninterruptible power supply 500 is shown in FIG9. Alternatively, referring to FIG8, when the fuse 526 is located between the connection point M and the load terminal H, the circuit topology of the uninterruptible power supply 500 is shown in FIG10.

[0086] In one possible embodiment, referring to FIG5, the circuit topology of the uninterruptible power supply 500 when the fuse 526 is located between the switch K and the connection point M is shown in FIG11. Alternatively, referring to FIG8, the circuit topology of the uninterruptible power supply 500 when the fuse 526 is located between the switch K and the connection point M is shown in FIG12.

[0087] In one possible embodiment, when the inverter circuit 521 includes a three-phase output terminal, the main circuit 520 also includes a fuse 526 connected to each phase output terminal of the inverter circuit 521 respectively. The specific connection method can be referred to the circuit topology diagram of the uninterruptible power supply 500 shown in any of the above figures 9 to 12. The embodiments of this application will not be described in detail here.

[0088] This application embodiment provides an uninterruptible power supply 500, and the main circuit 520 also includes a fuse 526. The fuse 526 is matched with a switch K and is used to provide overcurrent protection for the switch K. In this way, when the uninterruptible power supply 500 fails, the switch K can be prevented from being damaged, and the reliability of the uninterruptible power supply 500 can be improved.

[0089] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An uninterruptible power supply, characterized by The uninterrupted power supply device comprises a main path, a bypass path and a load end, the main path and the bypass path are used for supplying power to the load end; An inverter circuit and a switch are arranged on the main path, an output end of the inverter circuit is connected to the switch, and the switch is used for controlling conduction or disconnection between the output end of the inverter circuit and the load end; The bidirectional conduction device and the fuse are connected in series, and the bidirectional conduction device and the fuse connected in series are connected in parallel with the switch, the fuse is used for being disconnected when a fault current flows through the bidirectional conduction device and the fault current is greater than a first current threshold, and the bidirectional conduction device is used for being conducted when power supply to the load end by the bypass path is switched to power supply to the load end by the main path.

2. The uninterruptible power supply of claim 1, wherein, The fuse connected in series with the bidirectional conduction device is a first fuse, the switch is connected in series with a second fuse, the second fuse is used for being disconnected when a current flowing through the switch is greater than a second current threshold, and the second current threshold is greater than the first current threshold.

3. The uninterruptible power supply of claim 1 or 2, wherein, The bidirectional conduction device comprises two thyristors, the fuse connected in series with the bidirectional conduction device is a first fuse, and the two thyristors are connected in reverse parallel and connected in series with the first fuse.

4. The uninterrupted power supply according to claim 2, wherein Fusing of the first fuse is used for protecting the bidirectional conduction device.

5. The uninterrupted power supply according to claim 2 or 4, wherein Fusing of the second fuse is used for protecting the switch.

6. The uninterruptible power supply of claim 1 or 2, wherein, The bidirectional conduction device comprises two thyristors, the fuse connected in series with the bidirectional conduction device comprises two fuses, and the two thyristors are connected in reverse parallel after being connected in series with one of the fuses respectively.

7. The uninterruptible power supply of claim 1 or 2, wherein, The direction of the fault current is opposite to the direction of an output current of the output end of the inverter circuit.

8. The uninterruptible power supply of claim 1 or 2, wherein, The fuse comprises a plurality of sub-fuses connected in parallel.

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