Power supply equipment and uninterruptible power supply

Abstract

The invention discloses power supply equipment and an uninterruptible power supply, and relates to the technical field of power electronics, the power supply equipment comprises a switching circuit used for being connected between a power grid and a load, the switching circuit comprises N groups of thyristors which are connected in series, each group of thyristors comprises two thyristors which are reversely connected in parallel, and N is an integer greater than or equal to 2; the driving module is used for switching on and switching off the switching circuit and comprises N + 1 first transformers, a second transformer and a plurality of driving circuits, a primary winding of one first transformer is connected with a secondary winding of another adjacent first transformer, and the plurality of driving circuits are connected between the N groups of thyristors and the secondary windings of the N + 1 first transformers; a primary winding of the second transformer is used for connecting a driving power supply, and a secondary winding of the second transformer is connected with a primary winding of the first transformer. Therefore, when the thyristor is used in the uninterruptible power supply, the size of the uninterruptible power supply is reduced, and the hardware cost of the uninterruptible power supply is reduced.

Description

Technical Field

[0001] This application relates to the field of power electronics technology, and more particularly to a power supply device and an uninterruptible power supply. Background Technology

[0002] When an uninterruptible power supply (UPS) operates in a medium- or high-voltage power system, its main circuit operating voltage is often 10kV or higher. Thyristors are often used as the core power control element. By utilizing the high voltage withstand capability, high current carrying capacity, and fast switching characteristics of thyristors, the safe and stable operation of the main circuit is ensured in high-voltage and high-power scenarios.

[0003] Typically, the transformer or magnetic ring used to drive the thyristors is connected between the low-voltage control circuit and the high-voltage main circuit of the uninterruptible power supply (UPS). When transmitting signals or power, the transformer or magnetic ring needs to withstand a significant voltage difference, making it prone to partial discharge problems and causing electronic component failures. Therefore, it is necessary to measure the partial discharge status of each electronic component connected between the high and low potentials, requiring the introduction of more electronic components for partial discharge detection, increasing the size and hardware cost of the UPS. Summary of the Invention

[0004] Embodiments of this application provide a power supply device and an uninterruptible power supply (UPS) for reducing the size of the UPS and lowering its hardware cost when using thyristors.

[0005] In a first aspect, this application provides a power supply device, which includes a switching circuit and a drive module: the switching circuit is used to connect between the power grid and the load, the switching circuit includes N sets of thyristors connected in series, each set of thyristors includes two thyristors connected in reverse parallel, and N is an integer greater than or equal to 2; the drive module is used to turn on and off the switching circuit, the drive module includes N+1 first transformers, one second transformer and multiple drive circuits, the primary winding of one first transformer is connected to the secondary winding of another adjacent first transformer, the multiple drive circuits are connected between the N sets of thyristors and the secondary windings of the N+1 first transformers, the primary winding of the second transformer is used to connect to the drive power supply, and the secondary winding of the second transformer is connected to the primary winding of one first transformer.

[0006] When the power supply equipment is located on the main circuit of an uninterruptible power supply (UPS), and the UPS operates in a medium-voltage or high-voltage power system, thyristors connected in series are used in the power supply equipment to ensure the safe and stable operation of the main circuit under high-voltage and high-power scenarios. Since the transformer used to drive the thyristors is connected between the high-potential and low-potential regions, it is necessary to measure the partial discharge condition of the transformer corresponding to each thyristor.

[0007] In this embodiment, by setting up multiple first transformers and one second transformer, the first transformers directly connected to the multiple thyristors are placed in a high-potential region. The primary winding of one of the first transformers is directly connected to the secondary winding of an adjacent first transformer, forming a cascaded structure of multiple first transformers. Therefore, for a switching circuit, only one second transformer connected between the high and low potential regions is needed. When the second transformer is connected to any of the multiple first transformers, power can be supplied to the multiple first transformers to drive the thyristors. At this time, the primary and secondary windings of the multiple first transformers operate at the same high potential, and the voltage difference between their primary and secondary windings is small. Only partial discharge measurement of the second transformer connected between the high and low potential regions is required, thereby reducing the number of objects that need partial discharge detection in the power supply equipment when driving the thyristors. Furthermore, the amount of partial discharge in the power supply equipment is reduced, eliminating the need to repeatedly arrange sensors and detection circuits in the power supply equipment, reducing the size of the power supply equipment and the uninterruptible power supply where the power supply equipment is located, and lowering its hardware cost.

[0008] In some embodiments, the number of the above-mentioned multiple drive circuits is N+1, and the N+1 drive circuits are connected one-to-one with the N+1 first transformers; each drive circuit is connected to at least one thyristor for turning on and off the thyristor connected to it, and two thyristors with their cathodes connected are connected to the same drive circuit.

[0009] In this embodiment, a first transformer is provided to connect to the drive circuit corresponding to at least one thyristor to turn the thyristor on and off. This reduces the number of transformers required in the power supply equipment, lowers the driving cost of the thyristors, and reduces the size and hardware cost of the power supply equipment. Furthermore, by providing a drive circuit to connect to at least one thyristor, that is, when two thyristors with connected cathodes are connected to the same drive circuit, the drive circuit can be used to turn the thyristor on and off, further reducing the number of drive circuits required in the power supply equipment, thereby further reducing the size and hardware cost of the power supply equipment.

[0010] In some embodiments, the two thyristors with connected cathodes include a first thyristor and a second thyristor, and the drive circuit includes a first switch and a second switch; the first switch is connected between the gate of the first thyristor and one end of the secondary winding of the first transformer, and the cathode of the first thyristor is connected to the other end of the secondary winding; the second switch is connected between the gate of the second thyristor and one end of the secondary winding of the first transformer, and the cathode of the second thyristor is connected to the other end of the secondary winding.

[0011] In this embodiment, in the two thyristors with connected cathodes, different switches are connected between the gate of the two thyristors and one end of the secondary winding. The cathodes of the two thyristors are both connected to the other end of the secondary winding. This allows a first transformer to drive either of the two thyristors with connected negative terminals when the first switch and the second switch in the control drive circuit are turned on and off. This reduces the number of transformers and drive circuits required in the power supply equipment and reduces the hardware cost of the power supply equipment.

[0012] In some embodiments, the withstand voltage of the second transformer is greater than that of the first transformer.

[0013] In this embodiment, since the high-voltage transformer uses insulation materials that are more bulky and costly than the low-voltage transformer, and occupies a larger area in the circuit, the voltage difference between the primary and secondary windings of the second transformer is large, while the voltage difference between the primary and secondary windings of the first transformer is small. Therefore, only the second transformer can be set as a high-voltage transformer, and the first transformer can be set as a low-voltage transformer. This can reduce the packaging area of ​​the transformer in the power supply equipment, reduce the volume of the power supply equipment, and lower the manufacturing cost of the power supply equipment.

[0014] In some embodiments, the power supply equipment further includes a controller, which is used to: control the first switch to be turned on and the second switch to be turned off, so that the first thyristor is turned on and the second thyristor is turned off; control the second switch to be turned on and the first switch to be turned off, so that the second thyristor is turned on and the first thyristor is turned off.

[0015] In some embodiments, the drive circuit further includes a rectifier bridge, with the positive terminal of the rectifier bridge connected to the other end of the secondary winding and the negative terminal of the rectifier bridge connected to one end of the secondary winding.

[0016] In this embodiment, when the driving power supply outputs AC power to the second transformer, the second transformer provides AC power to the first transformer. By setting a rectifier bridge at the secondary winding, the AC power is converted into DC power after the rectifier bridge, so that a positive trigger voltage can always be applied between the gate and cathode of the thyristor at the secondary winding of the first transformer to meet the triggering and conduction requirements of the thyristor.

[0017] In some embodiments, the drive circuit further includes a capacitor and a third switch, with one end of the primary winding of the first transformer connected to one end of the capacitor, and the third switch connected between the other end of the primary winding of the first transformer and the other end of the capacitor.

[0018] In this embodiment, by connecting a capacitor in parallel across the primary winding of the first transformer, the electrical energy is first stored in the capacitor when powering the first transformer. When the first switch or the second switch in the drive circuit is turned on, the capacitor discharges rapidly through the primary winding, releasing a large amount of electrical energy instantly, thereby satisfying the large current required for the thyristor to be triggered and turned on.

[0019] In some embodiments, the secondary winding of the first transformer includes a first secondary winding and a second secondary winding; a first switch is connected between the gate of the first thyristor and one end of the first secondary winding, and the cathode of the first thyristor is connected to the other end of the first secondary winding; a second switch is connected between the gate of the second thyristor and one end of the second secondary winding, and the cathode of the second thyristor is connected to the other end of the second secondary winding.

[0020] In this embodiment, by setting two isolated secondary windings in the first transformer, and connecting each secondary winding to a switch in the drive circuit, the two thyristors with their cathodes connected can each form an independent current loop when they are turned on. This allows the first transformer to drive either of the two thyristors with their negative terminals connected when the first and second switches in the control drive circuit are turned on and off. This reduces the number of transformers and drive circuits required in the power supply equipment, thereby reducing the hardware cost of the power supply equipment.

[0021] In some embodiments, the power supply equipment further includes a controller for: controlling both the first switch and the second switch to be turned on, so that both the first thyristor and the second thyristor are turned on.

[0022] In this embodiment, the first transformer is equipped with two isolated secondary windings, and when the two thyristors with connected cathodes are connected to different secondary windings, the two isolated secondary windings are relatively independent when used as power supplies. This allows the first and second thyristors to conduct simultaneously when both switches in the control drive circuit are turned on, breaking the half-wave limitation of alternating conduction of two conductive channels with opposite conduction directions in the switching circuit. That is, when the first transformer drives the two thyristors to conduct simultaneously, the switching circuit can output full-wave continuous AC power, thereby improving the quality of the AC power output from the power supply equipment.

[0023] Secondly, embodiments of this application provide an uninterruptible power supply (UPS), which includes a main circuit, a maintenance bypass, and an inverter bypass. The main circuit and the maintenance bypass are used to connect between the power grid and the load, and the inverter bypass is used to connect between an energy storage device and the load. The main circuit includes the power supply equipment provided in the above embodiments. The UPS is used to: turn on the power supply equipment so that the power grid supplies power to the load through the main circuit; or, turn on the maintenance bypass so that the power grid supplies power to the load through the maintenance bypass; or, turn on the inverter bypass so that the energy storage device supplies power to the load through the inverter bypass.

[0024] In this embodiment, the beneficial effects of the second aspect can be referred to the description of the first aspect and any of its implementations, and will not be repeated here. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of an uninterruptible power supply provided in an embodiment of this application;

[0026] Figure 2 This is a schematic diagram of the structure of a power supply device;

[0027] Figure 3 This is a schematic diagram of another type of power supply equipment;

[0028] Figure 4 This is a schematic diagram of the structure of a power supply device provided in an embodiment of this application;

[0029] Figure 5 This is a schematic diagram of a driving circuit provided in an embodiment of this application;

[0030] Figure 6 This application provides a schematic diagram of the connection between a switching circuit and a driving module.

[0031] Figure 7 This is a schematic diagram of another driving circuit provided in an embodiment of this application;

[0032] Figure 8 for Figure 7 The current flow diagram of the provided drive circuit;

[0033] Figure 9 This is a schematic diagram of another driving circuit provided in an embodiment of this application;

[0034] Figure 10 for Figure 9 The current flow diagram of the provided drive circuit is shown. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] Before introducing the embodiments involved in this application, some technical terms related to the embodiments of this application will be introduced first.

[0037] Thyristor (silicon controlled rectifier, SCR): also known as silicon controlled rectifier, is a high-power semiconductor device with three PN junctions. It has unidirectional conductivity, can control high power with low power, and can achieve microsecond-level turn-on and turn-off.

[0038] Partial discharge: The phenomenon of local insulation breakdown of insulating materials under high voltage. It is manifested as a small discharge caused by excessive electric field strength in a local area, which will gradually erode the insulation and shorten the life of the device.

[0039] Please see Figure 1 , Figure 1 This is a schematic diagram of the structure of an uninterruptible power supply 100 provided in an embodiment of this application. Figure 1 As shown, the uninterruptible power supply 100 provided in this application embodiment includes a main circuit 110, a maintenance bypass 120, and an inverter bypass 130.

[0040] In this embodiment, the main circuit 110 is used to connect the power grid 210 and the load 300. By connecting the main circuit 110, the uninterruptible power supply 100 converts the AC power and outputs it to the load 300, allowing the power grid 210 to supply power to the load 300 through the main circuit 110. The maintenance bypass 120 is used to connect the power grid 210 and the load 300. When the uninterruptible power supply 100 is under maintenance, by connecting the switch K in the maintenance bypass 120, the power grid 210 supplies power to the load 300 through the maintenance bypass 120, ensuring uninterrupted power supply to the load 300 during maintenance. The uninterruptible power supply 100 is used to provide uninterrupted power to loads 300 with high power stability requirements, such as communication equipment and charging piles for electric vehicles.

[0041] Inverter bypass 130 is used to connect energy storage device 220 and load 300. Uninterruptible power supply 100 is used to enable energy storage device 220 to continue supplying power to load 300 for a period of time when main circuit 110 fails or grid 210 stops supplying power, thus preventing power outage of load 300. Inverter bypass 130 includes inverter circuit 131, thyristor SCR, and three-phase transformer TPT. When inverter bypass 130 is activated, inverter circuit 131 converts the DC power output from energy storage device 220 into AC power, which is then transmitted to three-phase transformer TPT through the activated thyristor SCR. The three-phase transformer TPT then converts the AC power to meet the power supply requirements of load 300.

[0042] When the uninterruptible power supply 100 operates in a medium-voltage or high-voltage power system, the operating voltage of its main circuit 110 is usually 10kV or higher. The uninterruptible power supply 100 can be divided into a high-potential region and a low-potential region. Figure 1(Not shown in the diagram). The high-potential region includes the part directly connected to the high-voltage main circuit 110, whose voltage is close to the operating voltage of the main circuit 110, such as the input and output terminals of the main circuit 110, and the high-voltage winding side of the transformer driving the thyristor SCR. This is the main path for power transmission and conversion in the uninterruptible power supply 100. The low-potential region includes the low-voltage control circuit, including controllers and drivers for controlling and detecting the high-potential region. Its voltage is much lower than that of the high-potential region, close to the ground or the control power supply voltage (usually tens to hundreds of volts), such as the controller, driver, and the low-voltage winding side of the transformer driving the thyristor SCR. The drive signal of the low-potential region is coupled to the high-potential region through electronic components such as transformers and magnetic rings, which can realize the control of the main circuit 110. The high-potential region and the low-potential region transmit signals through optical fiber. The high-potential region feeds back the signal to the controller on the low-potential region side for processing, so that the controller can detect the operating status of the equipment in the high-potential region in real time.

[0043] Typically, electronic components connected between high-potential and low-potential regions need to withstand significant voltage differences to transmit signals or power. This can lead to various issues. For example, the superposition of charges on the high-voltage side of the electronic component, defects in localized areas (such as bubbles, gaps, or impurities) causing poor insulation uniformity and resulting in localized electric field distortion, and the concentration of localized electric fields caused by structures like sharp points, floating potentials, or floating potentials on insulating surfaces can easily cause the electric field in a localized area of ​​the electronic component to exceed a critical value, resulting in short-term, localized breakdown discharge. Partial discharge generates high-energy spikes, which have a certain probability of damaging electronic components, controllers, and drivers in the power supply equipment. In severe cases, it can cause the power supply equipment to fail, affecting the safe operation of the uninterruptible power supply 100. Therefore, appropriate protection mechanisms need to be introduced to address partial discharge in the uninterruptible power supply 100. These mechanisms could include measuring the partial discharge of the connected electronic components and promptly disconnecting the electronic components from the circuit when the partial discharge exceeds a critical value, thus ensuring the safe operation of the uninterruptible power supply 100.

[0044] In some implementations, the main path includes power supply equipment 400, such as... Figure 2 As shown, Figure 2 This is a schematic diagram of the structure of a power supply device 400. The power supply device 400 provided in this embodiment includes a switching circuit 410 and a drive module 420.

[0045] In this embodiment, the switching circuit 410 is located in the high-potential region of the main circuit and is used to connect the power grid 210 and the load 300. Part of the drive module 420 is located in the high-potential region of the main circuit, and the rest is located in the low-potential region and is used to turn the switching circuit 410 on and off.

[0046] The switching circuit 410 incorporates multiple series-connected thyristors (SCRs) that conduct when the power grid 210 supplies power to the power supply device 400. SCRs offer better voltage withstand capability than field-effect transistors (FETs) and bipolar transistors (BJTs). By using multiple series-connected SCRs, the overall voltage withstand capability of the switching circuit 410 is improved, making it suitable for scenarios where the uninterruptible power supply 100 operates in medium- or high-voltage power systems. Furthermore, the power supply device 400 provided in this embodiment can also be applied to power supply systems other than uninterruptible power supplies that use SCRs as switching elements.

[0047] In this embodiment, the drive module 420 turns on the main circuit of the uninterruptible power supply 100 by connecting the thyristors SCRs connected in series in the switching circuit 410, and the power grid 210 supplies power to the load 300 through the main circuit connected by the switching circuit 410. The drive module 420 includes multiple magnetic rings MR for connecting the drive power supply 421. The multiple magnetic rings MR are connected between the high potential region and the low potential region to realize the transmission of drive signals and status feedback signals without electrical connection between the high and low potential regions. That is, some magnetic rings MR are used to turn on and off the thyristors SCRs in the switching circuit 410, and each thyristor SCR is connected to one magnetic ring MR. The remaining magnetic rings MR are used to provide feedback on the operating status of the series-connected thyristors SCRs. In this context, A1 and A2 in the drive module 420 correspond to A1 and A2 in the switch circuit 410, B1 and B2 in the drive module 420 correspond to B1 and B2 in the switch circuit 410, and C1 and C2 in the drive module 420 correspond to C1 and C2 in the switch circuit 410.

[0048] However, when the drive signal from the low-potential region is directly transmitted to the thyristor SCR in the high-potential region through the magnetic ring MR, since there is no drive power supply 421 on the high-voltage side, most faults cannot be directly detected on the high-voltage side and can only be judged indirectly by relying on the low-voltage side. The reliability of fault location is low and the response is lagging. In addition, there are many magnetic ring MRs connected between the high and low potential regions, and the number of partial discharge detection objects is large and the partial discharge is large. The number of sensors and detection circuits required is large, resulting in high cost of partial discharge detection.

[0049] In other implementations, such as Figure 3 As shown, Figure 3 This is a schematic diagram of another power supply device 400. The power supply device 400 provided in this embodiment includes a switching circuit 410 and a drive module 420.

[0050] In this embodiment, for the multiple thyristors SCRs connected in series in the switching circuit 410, the driving module 420 is equipped with multiple transformers T connected between the high-potential region and the low-potential region. Each transformer T is connected to a corresponding thyristor SCR. Specifically, A1 and A2 in the driving module 420 correspond to A1 and A2 in the switching circuit 410; B1 and B2 in the driving module 420 correspond to B1 and B2 in the switching circuit 410; and C1 and C2 in the driving module 420 correspond to C1 and C2 in the switching circuit 410. When the primary winding of the transformer T is connected to the driving power supply 421 in the low-potential region, based on the principle of electromagnetic induction, the secondary winding of the transformer T serves as the driving power supply 421 for the thyristors SCRs in the high-potential region, driving the thyristors SCRs to conduct.

[0051] However, because the primary and secondary windings of the transformer T, which is connected across the high-potential and low-potential regions, operate at different potentials, the voltage difference between them is large, making partial discharge a common problem. Furthermore, the large number of transformers T connected across these regions not only leads to high drive control costs but also results in a large number of objects requiring partial discharge detection, further increasing the cost of partial discharge detection.

[0052] To address the aforementioned issues, embodiments of this application provide a power supply device and an uninterruptible power supply (UPS) to reduce the size of the UPS and lower its hardware costs when using thyristors.

[0053] The specific embodiments involved in this application are described in detail below with reference to the accompanying drawings.

[0054] Please see Figure 4 , Figure 4 This is a structural schematic diagram of a power supply device 400 provided in an embodiment of this application. For example... Figure 4 As shown, the power supply device 400 provided in this embodiment includes a switching circuit 410 and a drive module 420.

[0055] In this embodiment, the switching circuit 410 is used to connect between the power grid 210 and the load 300. The switching circuit 410 includes N sets of thyristor SCRs connected in series. Each set of thyristor SCRs includes two thyristor SCRs connected in reverse parallel. That is, the anode of one thyristor SCR in each set is connected to the cathode of another thyristor SCR, and the cathode of one thyristor SCR is connected to the anode of another thyristor SCR. N is an integer greater than or equal to 2.

[0056] In some embodiments, when the power grid 210 outputs three-phase AC power to the power supply equipment 400, the power supply equipment 400 includes three switching circuits 410 and three drive modules 420. The three switching circuits 410 and the three drive modules 420 are connected one-to-one. Each switching circuit 410 corresponds to one phase of the three-phase AC power. The drive module 420 is used to independently control the conduction and cutoff of the corresponding switching circuit 410 to conduct and cut off the AC power of the corresponding phase. In addition, when N groups of thyristors (SCRs) in the switching circuit 410 are connected in series, including two anti-parallel connected thyristors (SCRs), the switching circuit 410 will form two conductive channels with opposite conduction directions, so that the switching circuit 410 can conduct bidirectionally when AC power is input from the power grid 210.

[0057] In this embodiment, the drive module 420 is used to turn the thyristor SCR in the switching circuit 410 on and off, and the drive module 420 includes N+1 first transformers T1 and one second transformer T2. The primary winding of one first transformer T1 is connected to the secondary winding of an adjacent first transformer T1, forming a cascaded structure among multiple first transformers T1. The primary winding of the second transformer T2 is used to connect to the drive power supply 421, and the secondary winding of the second transformer T2 is connected to the primary winding of one of the cascaded first transformers T1. When the uninterruptible power supply where the power supply equipment 400 is located operates in a medium-voltage or high-voltage power system, the N+1 first transformers T1 are located in the high-potential region of the power supply equipment 400, the second transformer T2 is connected between the high-potential region and the low-potential region, and the drive power supply 421 is located in the low-potential region to provide power to the second transformer T2.

[0058] In addition, the drive module 420 also includes multiple drive circuits 422, which are connected between N sets of thyristors SCRs and the secondary windings of N+1 first transformers T1. Each thyristor SCR includes an anode, a cathode, and a gate. The drive circuit 422 is connected between the gate and the cathode of the thyristor SCR. When the drive circuit 422 is turned on, the secondary winding of the first transformer T1 applies a positive trigger voltage between the gate and the cathode of the thyristor SCR through the turned-on drive circuit 422. After a trigger current is generated between the gate and the cathode, the anode and cathode of the thyristor SCR will change from a high-resistance blocking state to a low-resistance conducting state, thus turning on the thyristor SCR.

[0059] When the driving power supply 421 in the low-potential region provides power to the second transformer T2 connected between the high and low potential regions, and the second transformer T2 is connected to any one of the cascaded first transformers T1 to provide power to that first transformer T1, since the power can be transferred from the primary winding of one first transformer T1 to the secondary winding of another adjacent first transformer T1, the power can be supplied to the multiple first transformers T1 in the high-potential region through the second transformer T2 connected between the high and low potential regions.

[0060] In some embodiments, the power supply device 400 also includes a controller ( Figure 4 (Not shown in the diagram) The drive circuit 422 includes a switch. The controller controls the switch in the drive circuit 422, which is connected to the secondary winding of the first transformer T1, to turn on the drive circuit 422. The first transformer T1 applies a positive trigger voltage between the gate and cathode of the thyristor SCR through the turned-on drive circuit 422, thereby turning on the thyristor SCR.

[0061] Because the primary and secondary windings of the multiple first transformers T1 located in the high-potential region operate at the same high potential, the voltage difference between their primary and secondary windings is small, the electric field distribution is relatively uniform, and the probability of partial discharge is low. However, the primary and secondary windings of the second transformer T2, which is connected across the high-potential and low-potential regions, operate at different potentials. The voltage difference between its primary and secondary windings is large, easily forming areas of concentrated local electric field, leading to partial discharge. Furthermore, when a partial discharge breaks down the insulation material of the second transformer T2, the high voltage in the high-potential region will flow to the controller and driver in the low-potential region, causing malfunctions and damage to the controller and driver in the low-potential region, resulting in uninterruptible power supply (UPS) failure and shutdown, and even electric shock to personnel on the low-potential side.

[0062] In related technologies, each thyristor SCR in the switching circuit 410 is provided with a corresponding transformer connected between the high and low potential regions, and the primary and secondary windings of multiple transformers are isolated from each other. To ensure the safe and stable operation of the uninterruptible power supply, partial discharge detection needs to be performed on each transformer connected between the high and low potential regions. In the embodiment of this application, each thyristor SCR in the switching circuit 410 is provided with a first transformer T1 located in the high potential region. The primary winding of one of the multiple first transformers T1 is directly connected to the secondary winding of the adjacent first transformer T1, that is, the windings of the two first transformers T1 are electrically connected, forming a structure of multiple first transformers T1 cascaded together.

[0063] Based on this, in this embodiment, only one second transformer T2 needs to be set for a switching circuit 410, which is connected between the high and low potential regions. When the second transformer T2 is connected to any one of the multiple first transformers T1, power can be supplied to the multiple first transformers T1. Therefore, in this embodiment, only partial discharge detection needs to be performed on one second transformer T2 corresponding to each switching circuit 410 to determine whether there is an insulation failure problem that could cause damage or safety accidents to the uninterruptible power supply, thereby ensuring the safe and stable operation of the uninterruptible power supply. Furthermore, when the second transformer T2 supplies power to the multiple first transformers T1, each first transformer T1 used to drive the thyristor SCR in the high potential region can be regarded as an independent driving power supply 421, so that faults can be directly detected in the high potential region, improving the reliability of fault location and response speed.

[0064] For example, when the power supply equipment 400 includes three switching circuits 410 corresponding to three-phase AC power, the partial discharge detection object is changed from the traditional transformer connected between the high and low potential regions corresponding to each thyristor SCR to three second transformers T2 connected between the high and low potential regions corresponding to the three switching circuits 410. This reduces the number of partial discharge detection objects and the amount of partial discharge in the power supply equipment 400 is reduced. There is no need to repeatedly arrange sensors and detection circuits in the power supply equipment 400, and the wiring and debugging workload of the power supply equipment 400 is reduced, thereby reducing the cost of partial discharge detection.

[0065] In this embodiment, the first transformer T1 and the second transformer T2 used in the drive module 420 have the same withstand voltage, or the withstand voltage of the second transformer T2 used in the drive module 420 is greater than that of the first transformer T1, which is not limited here.

[0066] Because the voltage difference between the primary and secondary windings of the second transformer T2 is large, while the voltage difference between the primary and secondary windings of the first transformer T1 is small, if the withstand voltage of the second transformer T2 is set to be greater than its withstand voltage rating, the second transformer T2 can be set as a high-voltage transformer, such as with a withstand voltage rating greater than or equal to 75kVp, and the first transformer T1 can be set as a low-voltage transformer, such as with a withstand voltage rating greater than or equal to 6.5kVp. Since the insulation design standards for high-voltage and low-voltage transformers are different, the volume and cost of the insulation materials used in high-voltage transformers are higher, resulting in a larger volume, higher cost, and larger area occupied in the circuit compared to low-voltage transformers. Therefore, when only one high-voltage second transformer T2 is needed for each switching circuit 410, and the other multiple first transformers T1 are set as low-voltage transformers, the volume and manufacturing cost of the power supply equipment 400 can be reduced.

[0067] In some embodiments, the number of drive circuits 422 in the drive module 420 is 2N, and the 2N drive circuits 422 are connected one-to-one with 2N thyristors SCR. Each first transformer T1 is connected to at least one drive circuit 422, and each drive circuit 422 is connected to one thyristor SCR for turning on and off the thyristor SCR connected to it.

[0068] Please see Figure 5 , Figure 5 This is a schematic diagram of a driving circuit 422 provided in an embodiment of this application. The driving circuit 422 provided in this embodiment includes a switch K.

[0069] In this embodiment, when a first transformer T1 is connected to two drive circuits 422, the first transformer T1 includes a primary winding and two isolated secondary windings. The two isolated secondary windings share the same iron core. When a trigger pulse is input to the primary winding, the magnetic field change is synchronously coupled to the two secondary windings. However, each of the two secondary windings forms an independent current loop, which can be connected to the drive circuits 422 of two thyristors SCRs respectively. The primary winding is connected to the drive power supply 421 in the low-potential region. One drive circuit 422 is connected between the first secondary winding and one thyristor SCR, and the other drive circuit 422 is connected between the second secondary winding and another thyristor SCR.

[0070] Furthermore, when the first transformer T1 includes multiple isolated secondary windings, one first transformer T1 can connect to multiple drive circuits 422 and be used to turn on and off multiple thyristors SCRs connected to it through the drive circuits 422. Thus, by setting a second transformer T2 connected across the high and low potential regions, and multiple first transformers T1 located in the high potential region for connecting at least one thyristor SCR, the on and off control of multiple sets of thyristor SCRs in the switching circuit 410 can be achieved. This ensures the safe and stable operation of the transformer while reducing the number of transformers and the area required for transformer packaging in the power supply equipment, lowering the driving cost of the thyristor SCRs in the power supply equipment, and reducing the number of transformers requiring partial discharge detection, thereby lowering the partial discharge detection cost of the power supply equipment.

[0071] In some embodiments, the number of drive circuits 422 in the drive module 420 is N+1, and the N+1 drive circuits 422 are connected one-to-one with the N+1 first transformers T1. Each drive circuit 422 is connected to at least one thyristor SCR for turning on and off the connected thyristor SCR. Two thyristors SCRs with their cathodes connected are connected to the same drive circuit 422. Figure 4As shown, A1 and A2 in the drive module 420 correspond to A1 and A2 in the switch circuit 410; B1 and B2 in the drive module 420 correspond to B1 and B2 in the switch circuit 410; C1 and C2 in the drive module 420 correspond to C1 and C2 in the switch circuit 410. However, with... Figure 3 The connection methods between the transformer and the SCR thyristor are different. Figure 4 One of the first transformers, T1, can be used to drive two thyristors, SCR.

[0072] Thus, when N groups of thyristor SCRs (including those connected in reverse parallel) are connected in series, except for one thyristor SCR in the first and last groups which has no thyristor SCR connected to its negative terminal, there will be N-1 pairs of thyristor SCRs connected to their negative terminals. In this case, when the N groups of thyristor SCRs include 2N thyristor SCRs, only N+1 first transformers T1 and corresponding N+1 drive circuits 422 are needed to control the conduction and turn-off of the 2N thyristor SCRs. This reduces the number of transformers required to turn on the thyristor SCRs in the power supply equipment, thus reducing the hardware cost of the power supply equipment.

[0073] For example, such as Figure 6 As shown, Figure 6 This is a schematic diagram illustrating the connection between a switching circuit and a driving module provided in an embodiment of this application. The switching circuit provided in this embodiment includes three sets of thyristors, and the driving module includes four first transformers, one second transformer, and four driving circuits.

[0074] In this embodiment, when thyristors SCR-1 and SCR-2 form a set of thyristors connected in reverse series, thyristors SCR-3 and SCR-4 form a set of thyristors connected in reverse parallel, and thyristors SCR-5 and SCR-6 form a set of thyristors connected in reverse series, the negative terminal of thyristor SCR-2 is connected to the negative terminal of thyristor SCR-3, and the negative terminal of thyristor SCR-4 is connected to the negative terminal of thyristor SCR-5. The primary winding of the second transformer T2 is connected to the drive power supply, the secondary winding of the second transformer T2 is connected to the primary winding of the first transformer T1-1, the secondary winding of the first transformer T1-1 is connected to the primary winding of the first transformer T1-2, the secondary winding of the first transformer T1-2 is connected to the primary winding of the first transformer T1-3, and the secondary winding of the first transformer T1-3 is connected to the primary winding of the first transformer T1-4.

[0075] The drive circuit 422-1 is connected between the secondary winding of the first transformer T1-1 and the thyristor SCR-1. Specifically, points A1 and A2 connected to the drive circuit 422-1 correspond to points A1 and A2 connected to the thyristor SCR-1. The drive circuit 422-1 is used to turn the thyristor SCR-1 on and off. The drive circuit 422-2 is connected between the secondary winding of the first transformer T1-2 and the thyristors SCR-2 and SCR-3 connected to the negative terminal. Specifically, points B1 and B2 connected to the drive circuit 422-2 correspond to points B1 and B2 connected to the thyristor SCR-3. The drive circuit 422-2 is used to turn the thyristors SCR-2 and SCR-3 on and off. Drive circuit 422-3 is connected between the secondary winding of the first transformer T1-3 and the adjacent negative terminals of thyristors SCR-4 and SCR-5. Specifically, capacitors C1 and C2 connected to drive circuit 422-3 correspond to the potential points of thyristors SCR-5. Drive circuit 422-3 is used to turn on and off thyristors SCR-4 and SCR-5. Drive circuit 422-4 is connected between the secondary winding of the first transformer T1-4 and thyristor SCR-6. Drive circuit 422-4 is used to turn on and off thyristor SCR-6. Thus, when there are three sets of thyristors, including six thyristors, only four first transformers and four corresponding drive circuits are needed to achieve the on / off control of all six thyristors.

[0076] In the embodiments of this application, firstly, only one second transformer T2 needs to be set for each switching circuit 410, which is connected across the high and low potential regions. When the second transformer T2 is connected to any one of the multiple first transformers T1, power can be supplied to the multiple first transformers T1, thereby reducing the number of transformers that need to be detected for partial discharge in the power supply device 400. Furthermore, the amount of partial discharge in the power supply device 400 is reduced, eliminating the need to repeatedly arrange sensors and detection circuits in the power supply device 400, thus reducing the cost of partial discharge detection, the size of the power supply device 400, and the hardware cost. Secondly, one first transformer T1 is set to connect at least one drive circuit 422 to turn on and off the thyristor SCR connected to the drive circuit 422, thereby reducing the number of transformers that need to be set in the power supply device 400, reducing the driving cost of the thyristor SCR in the power supply device 400, and further reducing the size and hardware cost of the power supply device 400. Furthermore, a drive circuit 422 is provided to connect at least one thyristor SCR. The drive circuit 422 is used to turn on and off the thyristor SCR connected to it. Two thyristor SCRs with their cathodes connected can be connected to the same drive circuit 422, which reduces the number of drive circuits 422 that need to be provided in the power supply equipment 400. This further reduces the driving cost of the thyristor SCRs in the power supply equipment 400, and further reduces the size and hardware cost of the power supply equipment 400.

[0077] The following example illustrates the connection between the drive circuit 422 and the two thyristors SCRs connected to their cathodes, including the first thyristor SCR1 and the second thyristor SCR2. The first thyristor SCR1 and the second thyristor SCR2, connected to their cathodes, have opposite conduction directions. For instance, when the AC power input from the power grid 210 to the switching circuit 410 is in the positive half-cycle, the first thyristor SCR1 conducts; when the AC power is in the negative half-cycle, the second thyristor SCR2 conducts.

[0078] As one implementation method, such as Figure 7 As shown, Figure 7 This is a schematic diagram of another driving circuit 422 provided in an embodiment of this application. The driving circuit 422 provided in this embodiment includes a first switch K1 and a second switch K2.

[0079] In this embodiment, the first switch K1 is connected between the gate of the first thyristor SCR1 (one of the two thyristors with connected cathodes) and one end of the secondary winding of the first transformer T1, with the cathode of the first thyristor SCR1 connected to the other end of the secondary winding. The second switch K2 is connected between the gate of the second thyristor SCR2 (one of the two thyristors with connected cathodes) and one end of the secondary winding of the first transformer T1, with the cathode of the second thyristor SCR2 connected to the other end of the secondary winding.

[0080] Furthermore, the drive circuit 422 also includes a rectifier bridge RB. The positive terminal of the rectifier bridge RB is connected to the other end of the secondary winding, and the negative terminal of the rectifier bridge RB is connected to one end of the secondary winding. If the drive power supply outputs AC power to the second transformer, the second transformer provides AC power to the first transformer T1. The secondary winding of the first transformer T1 outputs AC power. By setting the rectifier bridge RB at the secondary winding, the AC power is converted into DC power after being rectified by the rectifier bridge RB, so that a positive trigger voltage can always be applied between the gate and cathode of the thyristor SCR at the secondary winding of the first transformer T1 to meet the triggering and conduction requirements of the thyristor SCR.

[0081] In addition, the drive circuit 422 also includes a capacitor C and a third switch K3. One end of the primary winding of the first transformer T1 is connected to one end of the capacitor C, and the third switch K3 is connected between the other end of the primary winding of the first transformer T1 and the other end of the capacitor C. The first switch K1 and the second switch K2 may include mechanical switches, metal-oxide-semiconductor field-effect transistors (MOSFETs), insulated-gate bipolar transistors (IGBTs), etc., and this application does not limit the specific type of switch.

[0082] When the drive power supply supplies power to the second transformer, the controller turns on the third switch K3 connected to the primary winding of the first transformer T1, enabling the second transformer to supply power to the cascaded first transformers T1. Specifically, when supplying power to the first transformer T1, electrical energy is first stored in the capacitor C connected to the primary winding of the first transformer T1. When the first switch K1 or the second switch K2 in the drive circuit 422 turns on, the capacitor C rapidly discharges through the primary winding, instantly releasing a large amount of electrical energy to meet the high current required for the triggering and conduction of the thyristor SCR.

[0083] like Figure 8 As shown, Figure 8 for Figure 7 The current flow diagram of the provided drive circuit 422.

[0084] like Figure 8 As shown in (a), when the drive power supply supplies power to the second transformer, since one of the cascaded first transformers T1 is connected to the second transformer, the second transformer supplies power to the cascaded first transformers T1. When the controller controls the first switch K1 in the drive circuit 422 to be turned on and the second switch K2 to be turned off, the first thyristor SCR1 can be turned on and the second thyristor SCR2 can be turned off.

[0085] Specifically, the current flows out from one end of the secondary winding of the first transformer T1, passes through the first switch K1, the gate of the first thyristor SCR1, and the cathode of the first thyristor SCR1, and returns to the other end of the secondary winding of the first transformer T1. A positive trigger voltage is applied between the gate and cathode of the first thyristor SCR1 in the secondary winding of the first transformer T1 to drive the first thyristor SCR1 to conduct.

[0086] like Figure 8 As shown in (b), when the drive power supply supplies power to the second transformer, the second transformer supplies power to the multiple cascaded first transformers T1. When the controller controls the second switch K2 in the drive circuit 422 to be turned on and the first switch K1 to be turned off, the second thyristor SCR2 can be turned on and the first thyristor SCR1 can be turned off.

[0087] Specifically, the current flows out from one end of the secondary winding of the first transformer T1, passes through the conducting second switch K2, the gate of the second thyristor SCR2, and the cathode of the second thyristor SCR2, and returns to the other end of the secondary winding of the first transformer T1. A positive trigger voltage is applied between the gate and cathode of the second thyristor SCR2 in the secondary winding of the first transformer T1 to drive the second thyristor SCR2 to conduct.

[0088] In some implementations, a voltage divider resistor is connected between the anode and the gate of the thyristor, and another voltage divider resistor is connected between the gate and the other end of the secondary winding. The resistance of the voltage divider resistor between the anode and the gate is much larger than the resistance of the voltage divider resistor between the gate and the other end of the secondary winding, so as to ensure that the secondary winding can provide a stable positive trigger voltage to the gate of the thyristor during the driving process.

[0089] In this embodiment, when the power grid outputs AC power to the power supply equipment, and the N groups of thyristors in the switching circuit, including two thyristors connected in reverse parallel, are connected in series, the switching circuit will form two conductive channels with opposite conduction directions, allowing the switching circuit to conduct bidirectionally when AC power is input from the power grid. Using the aforementioned drive circuit 422, in the two thyristors with connected cathodes, different switches are connected between the gate of the two thyristors and one end of the secondary winding. The cathodes of both thyristors are connected to the other end of the secondary winding. A first transformer T1 can drive either of the two thyristors with connected negative terminals, thereby reducing the number of transformers required in the power supply equipment and reducing the hardware cost of the power supply equipment. Furthermore, by controlling the conduction and cutoff of the first switch K1 and the second switch K2 in the drive circuit 422, the switch circuit can alternately conduct two conductive channels with opposite conduction directions to transmit AC power to the load.

[0090] As one implementation method, such as Figure 9 As shown, Figure 9 This is a schematic diagram of another driving circuit 422 provided in an embodiment of this application. The driving circuit 422 provided in this embodiment includes a first switch K1 and a second switch K2.

[0091] In this embodiment, the first transformer includes a primary winding Pri and a secondary winding. The secondary winding of the first transformer includes a first secondary winding Sec1 and a second secondary winding Sec2. The isolated first secondary winding Sec1 and the second secondary winding Sec2 share the same iron core, but each of the two secondary windings forms an independent current loop, which can be connected to the drive circuits 422 of two thyristors respectively. The first switch K1 is connected between the gate of the first thyristor SCR1 and one end of the first secondary winding Sec1 of the two thyristors with connected cathodes. The cathode of the first thyristor SCR1 is connected to the other end of the first secondary winding Sec1. The second switch K2 is connected between the gate of the second thyristor SCR2 and one end of the second secondary winding Sec2 of the two thyristors with connected cathodes. The cathode of the second thyristor SCR2 is connected to the other end of the second secondary winding Sec2.

[0092] In addition, the drive circuit 422 also includes the aforementioned rectifier bridge RB, capacitor C, and third switch K3, as described above. Figure 7 The contents of that document will not be repeated here.

[0093] like Figure 10 As shown, Figure 10 for Figure 9 The current flow diagram of the provided drive circuit 422.

[0094] like Figure 10 As shown in (a), when the drive power supply supplies power to the second transformer, since one of the cascaded first transformers is connected to the second transformer, the second transformer supplies power to the cascaded first transformers. When the controller controls the first switch K1 in the drive circuit 422 to be turned on and the second switch K2 to be turned off, the first thyristor SCR1 can be turned on and the second thyristor SCR2 can be turned off.

[0095] Specifically, the current flows out from one end of the first secondary winding Sec1 of the first transformer, passes through the first switch K1, the gate of the first thyristor SCR1, and the cathode of the first thyristor SCR1, and returns to the other end of the first secondary winding Sec1 of the first transformer. A positive trigger voltage is applied between the gate and cathode of the first thyristor SCR1 in the first secondary winding Sec1 to drive the first thyristor SCR1 to conduct.

[0096] like Figure 10 As shown in (b), when the drive power supply supplies power to the second transformer, the second transformer supplies power to the multiple cascaded first transformers. When the controller controls the second switch K2 in the drive circuit 422 to be turned on and the first switch K1 to be turned off, the second thyristor SCR2 can be turned on and the first thyristor SCR1 can be turned off.

[0097] Specifically, the current flows out from one end of the second secondary winding Sec2 of the first transformer, passes through the conducting second switch K2, the gate of the second thyristor SCR2, and the cathode of the second thyristor SCR2, and returns to the other end of the second secondary winding Sec2 of the first transformer. A positive trigger voltage is applied between the gate and cathode of the second secondary winding Sec2 to drive the second thyristor SCR2 to conduct.

[0098] like Figure 10 As shown in (c), when the driving power supply supplies power to the second transformer, the second transformer supplies power to the multiple cascaded first transformers. When the controller controls the first switch K1 and the second switch K2 in the drive circuit 422 to be turned on, the first thyristor SCR1 and the second thyristor SCR2 can be turned on.

[0099] Specifically, current flows out from one end of the first secondary winding Sec1 of the first transformer, passes through the conducting first switch K1, the gate of the first thyristor SCR1, and the cathode of the first thyristor SCR1, and returns to the other end of the first secondary winding Sec1 of the first transformer. A positive trigger voltage is applied between the gate and cathode of the first thyristor SCR1 in the first secondary winding Sec1 to drive the first thyristor SCR1 to conduct. Furthermore, current flows out from one end of the second secondary winding Sec2 of the first transformer, passes through the conducting second switch K2, the gate of the second thyristor SCR2, and the cathode of the second thyristor SCR2, and returns to the other end of the second secondary winding Sec2 of the first transformer. A positive trigger voltage is applied between the gate and cathode of the second thyristor SCR2 in the second secondary winding Sec2 to drive the second thyristor SCR2 to conduct.

[0100] Thus, by setting two isolated secondary windings in the first transformer, and connecting each secondary winding to a switch in the drive circuit 422, the first thyristor SCR1 and the second thyristor SCR2 will each form an independent current loop when they are turned on. The two isolated secondary windings are relatively independent when used as power supplies, so that when both switches in the control drive circuit 422 are turned on, the first thyristor SCR1 and the second thyristor SCR2 can be turned on simultaneously.

[0101] In the switching circuit, when two conductive channels with opposite conduction directions are alternately turned on, after one of the two thyristors connected to the negative terminal turns off, the other thyristor turns on to avoid short circuit caused by the two thyristors turning on simultaneously near the zero-crossing point of the AC voltage. In this embodiment, a first transformer can drive the two thyristors connected to the negative terminal to turn on simultaneously, and the two thyristors will form independent current loops when they are turned on, without affecting each other. The triggering of thyristor conduction does not depend on the position of the zero-crossing point of the AC voltage. The two thyristors can be triggered simultaneously at any position to form a bidirectional current path, avoid current interruption, and make the output waveform of the power supply equipment free of dead zone and with lower harmonics.

[0102] In this embodiment, when the power grid outputs AC power to the power supply equipment, and the N groups of thyristors in the switching circuit, including two thyristors connected in reverse parallel, are connected in series, the switching circuit will form two conductive channels with opposite conduction directions, allowing the switching circuit to conduct bidirectionally when AC power is input from the power grid. Using the aforementioned drive circuit 422, a first transformer can drive either one of the two thyristors connected to the negative terminal to conduct, or drive both thyristors to conduct. This not only reduces the number of transformers required in the power supply equipment, thus reducing the hardware cost, but also breaks the half-wave limitation of alternating conduction of the two conductive channels with opposite conduction directions in the switching circuit. That is, when the first transformer drives both thyristors to conduct simultaneously, the switching circuit can output full-wave continuous AC power, thereby improving the quality of the AC power output from the power supply equipment.

[0103] 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. A power supply device, characterized in that, The power supply equipment includes: A switching circuit for connecting a power grid and a load, the switching circuit comprising N sets of thyristors connected in series, each set of thyristors comprising two thyristors connected in anti-parallel, where N is an integer greater than or equal to 2; A drive module is used to turn the switching circuit on and off. The drive module includes N+1 first transformers, one second transformer, and multiple drive circuits. The primary winding of one first transformer is connected to the secondary winding of an adjacent first transformer. The multiple drive circuits are connected between the N sets of thyristors and the secondary windings of the N+1 first transformers. The primary winding of the second transformer is used to connect to the drive power supply. The secondary winding of the second transformer is connected to the primary winding of one first transformer.

2. The power supply equipment according to claim 1, characterized in that, The number of the plurality of driving circuits is N+1, and the N+1 driving circuits are connected one-to-one with the N+1 first transformers; Each of the drive circuits is connected to at least one of the thyristors for turning on and off the thyristors connected thereto, and two thyristors with their cathodes connected are connected to the same drive circuit.

3. The power supply equipment according to claim 2, characterized in that, The two thyristors connected to the cathodes include a first thyristor and a second thyristor, and the driving circuit includes a first switch and a second switch; The first switch is connected between the gate of the first thyristor and one end of the secondary winding of the first transformer, and the cathode of the first thyristor is connected to the other end of the secondary winding. The second switch is connected between the gate of the second thyristor and one end of the secondary winding of the first transformer, and the cathode of the second thyristor is connected to the other end of the secondary winding.

4. The power supply equipment according to claim 3, characterized in that, The withstand voltage of the second transformer is greater than that of the first transformer.

5. The power supply equipment according to claim 3, characterized in that, The power supply equipment also includes a controller, the controller being used for: Controlling the first switch to be turned on and the second switch to be turned off, thereby turning on the first thyristor and turning off the second thyristor; Controlling the second switch to turn on and the first switch to turn off causes the second thyristor to turn on and the first thyristor to turn off.

6. The power supply equipment according to claim 3, characterized in that, The drive circuit also includes a rectifier bridge, the positive terminal of which is connected to the other end of the secondary winding, and the negative terminal of which is connected to one end of the secondary winding.

7. The power supply equipment according to claim 3, characterized in that, The driving circuit also includes a capacitor and a third switch. One end of the primary winding of the first transformer is connected to one end of the capacitor, and the third switch is connected between the other end of the primary winding of the first transformer and the other end of the capacitor.

8. The power supply equipment according to any one of claims 3 to 7, characterized in that, The secondary winding of the first transformer includes a first secondary winding and a second secondary winding; The first switch is connected between the gate of the first thyristor and one end of the first secondary winding, and the cathode of the first thyristor is connected to the other end of the first secondary winding. The second switch is connected between the gate of the second thyristor and one end of the second secondary winding, and the cathode of the second thyristor is connected to the other end of the second secondary winding.

9. The power supply equipment according to claim 8, characterized in that, The power supply equipment also includes a controller, the controller being used for: The first switch and the second switch are both turned on, so that the first thyristor and the second thyristor are both turned on.

10. An uninterruptible power supply, characterized in that, The uninterruptible power supply (UPS) includes a main circuit, a maintenance bypass, and an inverter bypass. The main circuit and the maintenance bypass are used to connect between the power grid and the load. The inverter bypass is used to connect between the energy storage device and the load. The main circuit includes the power supply equipment as described in any one of claims 1 to 9. The UPS is used for: The power supply equipment is switched on, allowing the power grid to supply power to the load through the main circuit; or... The maintenance bypass is activated, allowing the power grid to supply power to the load through the maintenance bypass; or... The inverter bypass is activated, allowing the energy storage device to supply power to the load through the inverter bypass.

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