Uninterruptible power supply

Abstract

The invention provides an uninterruptible power supply, which comprises a PFC booster circuit of which the input end is used for being connected with commercial power input and one of the input ends is connected with a target polarity end of a battery pack; the input end of the direct current bus is connected with the output end of the PFC booster circuit; the input end of the conversion circuit is connected with the output end of the direct-current bus, and the output end is connected with a load; a first port of the battery bidirectional circuit corresponding to the battery side is used for connecting a target polarity end, and a second port is used for connecting the other polarity end of the battery pack; a third port corresponding to the bus side is used for connecting a positive bus or a negative bus, and a fourth port is used for connecting a zero line; the balance bridge circuit is connected with the direct current bus and used for balancing the voltage difference between the positive capacitor and the negative capacitor; in the battery power supply mode, the battery pack charges the positive capacitor or the negative capacitor through the PFC booster circuit, and the battery pack charges the positive capacitor or the negative capacitor through the battery bidirectional circuit. According to the invention, the multiplexing rate of the circuit in the UPS can be improved.

Description

Technical Field

[0001] The present application relates to the field of power electronics technology, and in particular to an uninterruptible power supply. Background Art

[0002] The basic structure of an uninterruptible power supply (UPS) includes a power factor correction (PFC) boost circuit that converts AC power into DC power, a battery bidirectional circuit, and a conversion circuit that converts DC power. When the AC power supplied by the mains is normal, the mains supplies power to the DC bus to enable the load to work normally. At the same time, the battery stores energy and maintains a normal charging voltage. When the mains power supply is interrupted, the battery supplies power to the DC bus to ensure that the load is not disconnected.

[0003] Among them, when the battery is powered, only the battery bidirectional circuit is used for power supply, and the PFC boost circuit is only used under the AC power state. The AC power supply circuit and the battery power supply circuit are two parts of the circuit, which need to be designed and operated independently, resulting in low circuit utilization in the UPS; and, because the battery pack needs to supply power to the DC bus when the battery is powered to ensure the normal operation of the load, the power of the battery bidirectional circuit for battery charging and discharging needs to meet the rated power of the UPS. The circuit is relatively complex and requires more components, resulting in a larger circuit size and higher cost. Summary of the invention

[0004] The embodiment of the present application provides an uninterruptible power supply to improve the reuse rate of circuits in a UPS and reduce the size and cost of the entire machine.

[0005] In a first aspect, an embodiment of the present application provides an uninterruptible power supply, including:

[0006] A PFC boost circuit, whose input terminal is used to connect to the mains input and one of the input terminals is connected to the target polarity terminal of the battery pack;

[0007] A DC bus, whose input end is connected to the output end of the PFC boost circuit; wherein the DC bus includes a positive bus, a negative bus and a neutral line; a positive capacitor is connected between the positive bus and the neutral line, and a negative capacitor is connected between the neutral line and the negative bus;

[0008] A conversion circuit, whose input end is connected to the output end of the DC bus, and whose output end is used to connect to a load;

[0009] A battery bidirectional circuit, wherein the first port corresponding to the battery side is used to connect to the target polarity end, and the second port is used to connect to the other polarity end of the battery pack; the third port corresponding to the bus side is used to connect to the positive bus or negative bus, and the fourth port is used to connect to the neutral line;

[0010] A balancing bridge circuit is connected to the DC bus and is used to balance the voltage difference between the positive capacitor and the negative capacitor.

[0011] In a possible implementation, the battery bidirectional circuit includes a first inductor, a first switch tube, and a second switch tube;

[0012] The first end of the first inductor serves as the first port of the battery bidirectional circuit;

[0013] The second end of the first inductor is respectively connected to the first end of the first switch tube and the first end of the second switch tube;

[0014] The second end of the first switch tube serves as the second port and the fourth port of the battery bidirectional circuit;

[0015] The second end of the second switch tube serves as the third port of the battery bidirectional circuit;

[0016] When the target polarity end is the positive electrode of the battery pack, the third port of the battery bidirectional circuit is connected to the positive bus;

[0017] When the target polarity end is the negative electrode of the battery pack, the third port of the battery bidirectional circuit is connected to the negative bus.

[0018] In a possible implementation, the battery bidirectional circuit includes a first inductor, a first switch tube, and a second switch tube;

[0019] The first end of the first switch tube serves as the first port of the battery bidirectional circuit;

[0020] The second end of the first switch tube is respectively connected to the first end of the first inductor and the first end of the second switch tube;

[0021] The second end of the first inductor serves as the second port and the fourth port of the battery bidirectional circuit;

[0022] The second end of the second switch tube serves as the third port of the battery bidirectional circuit;

[0023] When the target polarity end is the positive electrode of the battery pack, the third port of the battery bidirectional circuit is connected to the negative bus;

[0024] When the target polarity end is the negative electrode of the battery pack, the third port of the battery bidirectional circuit is connected to the positive bus.

[0025] In one possible implementation, the uninterruptible power supply also includes a controller, which is used to: in a battery power supply mode, the battery pack charges the positive capacitor or the negative capacitor through a PFC boost circuit, and the battery pack charges the positive capacitor or the negative capacitor through a battery bidirectional circuit.

[0026] In a possible implementation, the uninterruptible power supply further includes a first switch, a second switch, and a third switch;

[0027] The first end of the first switch is used to connect to the mains input, and the second end of the first switch is connected to the input end of the PFC boost circuit;

[0028] The first end of the second switch is used to connect the target polarity end of the battery pack, and the second end of the second switch is connected to the input end of the PFC boost circuit;

[0029] The first end of the third switch is used to connect to the positive electrode of the battery pack, and the second end of the third switch is connected to a port in the battery bidirectional circuit that is used to connect to the positive electrode of the battery pack.

[0030] In a possible implementation, the PFC boost circuit includes a second inductor, a first diode, a second diode, a third switch tube, and a fourth switch tube;

[0031] The first end of the second inductor serves as the input end of the PFC boost circuit; the second end of the second inductor is respectively connected to the anode of the first diode, the cathode of the second diode and the collector of the third switch tube;

[0032] The cathode of the first diode is connected to the positive bus;

[0033] The anode of the second diode is connected to the negative bus;

[0034] The emitter of the third switch tube is connected to the emitter of the fourth switch tube, and the collector of the fourth switch tube is used to connect to the neutral line.

[0035] In a possible implementation, the first switch includes a first thyristor and a second thyristor, and the second switch includes a third thyristor;

[0036] The PFC boost circuit includes a second inductor, a third inductor, a first diode, a second diode, a third switch tube and a fourth switch tube;

[0037] The anode of the first thyristor and the cathode of the second thyristor are connected and serve as the first end of the first switch; the cathode of the first thyristor serves as the first port of the second end of the first switch and is connected to the first end of the second inductor; the anode of the second thyristor serves as the second port of the second end of the first switch and is connected to the first end of the third inductor;

[0038] The second end of the second inductor is connected to the anode of the first diode and the collector of the third switch tube respectively; the cathode of the first diode is connected to the positive bus; the emitter of the third switch tube is used to connect to the neutral line;

[0039] The second end of the third inductor is connected to the emitter of the fourth switch tube and the cathode of the second diode respectively; the anode of the second diode is connected to the negative bus; the collector of the fourth switch tube is used to connect to the neutral line;

[0040] When the target polarity end is the positive electrode of the battery pack, the anode of the third thyristor serves as the first end of the second switch, and the cathode of the third thyristor is connected to the first end of the second inductor; when the target polarity end is the negative electrode of the battery pack, the cathode of the third thyristor serves as the first end of the second switch, and the anode of the third thyristor is connected to the first end of the third inductor.

[0041] In a possible implementation, the balanced bridge circuit includes a fourth inductor, a seventh switch tube, and an eighth switch tube;

[0042] The first end of the fourth inductor is used to connect the neutral line, and the second end of the fourth inductor is respectively connected to the emitter of the seventh switch tube and the collector of the eighth switch tube;

[0043] The collector of the seventh switch tube is used to connect the positive bus;

[0044] The emitter of the eighth switch tube is used to connect to the negative bus.

[0045] In a possible implementation, the uninterruptible power supply further includes a controller, and the controller is configured to:

[0046] When the AC power input from the mains is normal, the first switch is controlled to be turned on, the second switch is turned off, and the third switch is controlled to be turned on; the PFC boost circuit is controlled to convert the AC power input from the mains into DC power, and the conversion circuit is controlled to convert the DC power into AC power to provide to the load; and the battery bidirectional circuit is controlled to charge the battery pack;

[0047] When the AC power input from the mains fails, the first switch is controlled to be disconnected, the second switch is controlled to be turned on, and the third switch is controlled to be turned on; the electric energy stored in the battery pack is controlled to be input into the PFC boost circuit, and the PFC boost circuit is controlled to perform power conversion on the electric energy input from the battery pack and input it into the positive bus or the negative bus; the electric energy stored in the battery pack is controlled to be input into the battery bidirectional circuit, and the battery bidirectional circuit is controlled to discharge the electric energy input from the battery pack to the positive bus or the negative bus; and, the balancing bridge circuit is controlled to balance the voltage difference between the positive capacitor and the negative capacitor, and the conversion circuit is controlled to convert the DC power into AC power and provide it to the load.

[0048] In a possible implementation, the mains input is three-phase alternating current, the uninterruptible power supply includes three first switches, three second switches and three PFC boost circuits, and each phase of the three-phase alternating current corresponds to a first switch, a second switch and a PFC boost circuit;

[0049] For each phase, a first end of the first switch of the phase is used to connect the AC power of the phase, and a second end of the first switch of the phase is connected to an input end of the PFC boost circuit of the phase;

[0050] An input end of the corresponding PFC boost circuit is also connected to the second end of the second switch of the phase, and an output end of the corresponding PFC boost circuit is connected to the bus.

[0051] In a possible implementation, the mains power input is three-phase alternating current, the uninterruptible power supply includes three first switches, and each phase of the three-phase alternating current corresponds to a first switch;

[0052] For each phase, the first end of the corresponding first switch is used to connect the alternating current of the phase; the first port of the second end of the corresponding first switch is connected to the first end of the second inductor, and the second port of the second end of the corresponding first switch is connected to the first end of the third inductor.

[0053] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0054] The embodiment of the present application connects the battery pack and the PFC boost circuit, so that when there is a fault in the AC power input at the mains input terminal, that is, in the battery state, the electric energy of the battery pack can be discharged to the DC bus through the PFC boost circuit; the battery pack is also connected to the positive bus or the negative bus in the DC bus through the battery bidirectional circuit, and the electric energy in the battery pack is discharged to the DC bus through the battery bidirectional circuit. The DC bus can be powered by the PFC boost circuit and the battery bidirectional circuit at the same time. Compared with only rectifying and boosting by the battery bidirectional circuit, the power of the battery bidirectional circuit can be reduced, so that the power of the battery bidirectional circuit does not need to meet the rated power of the UPS, thereby reducing the volume and cost of the battery bidirectional circuit. Moreover, the DC bus is powered by the PFC boost circuit and the battery bidirectional circuit at the same time, so that the PFC boost circuit and the battery bidirectional circuit can be fully utilized when powered by AC power and battery, thereby improving the reuse rate of the circuit; in addition, since the PFC boost circuit and the battery bidirectional circuit are both connected to one polarity end in the DC bus when the battery pack is used for boosting, half of the DC bus is boosted, and there is an imbalance problem between the positive bus and the negative bus in the DC bus, a balancing bridge circuit is connected to the DC bus, and the balancing bridge circuit is used to balance the voltage difference between the positive capacitor and the negative capacitor. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0056] Figure 1 It is a structural schematic diagram of an uninterruptible power supply provided in an embodiment of the present application;

[0057] Figure 2A It is a structural schematic diagram of a first battery bidirectional circuit provided in an embodiment of the present application;

[0058] Figure 2B is a structural schematic diagram of a second battery bidirectional circuit provided in an embodiment of the present application;

[0059] Figure 3 It is a structural schematic diagram of an uninterruptible power supply of a single-phase multiplexed positive busbar boosting positive busbar provided in an embodiment of the present application;

[0060] Figure 4 It is a structural schematic diagram of an uninterruptible power supply of a single-phase multiplexed negative bus boosting negative bus provided in an embodiment of the present application;

[0061] Figure 5 It is a schematic diagram of the structure of an uninterruptible power supply that provides a single-phase multiplexing negative bus to boost the positive bus in an embodiment of the present application;

[0062] Figure 6 This is a circuit structure diagram of a first single-phase multiplexed positive bus boosting uninterruptible power supply provided in an embodiment of the present application;

[0063] Figure 7 It is a circuit structure diagram of a second single-phase multiplexed positive bus boosting uninterruptible power supply provided in an embodiment of the present application;

[0064] Figure 8 This is a circuit structure diagram of a third type of uninterruptible power supply for a single-phase multiplexed positive bus and a positive bus booster provided in an embodiment of the present application;

[0065] Fig. 9 This is a circuit structure diagram of a first uninterruptible power supply with a three-phase multiplexed positive bus and a positive bus booster provided in an embodiment of the present application;

[0066] Fig.10 This is a circuit structure diagram of a second uninterruptible power supply of a three-phase multiplexed positive bus boosting positive bus provided in an embodiment of the present application;

[0067] Fig.11 This is a circuit structure diagram of an uninterruptible power supply for a three-phase multiplexed negative bus and a negative bus booster provided in an embodiment of the present application;

[0068] Fig.12 This is a circuit structure diagram of an uninterruptible power supply for a three-phase multiplexed positive busbar and a negative busbar;

[0069] Fig.13A This is a schematic diagram of the operation of the uninterruptible power supply provided in an embodiment of the present application in a positive half-wave mode of mains power supply;

[0070] Fig. 13B It is a schematic diagram of the operation of the uninterruptible power supply provided in an embodiment of the present application in a negative half-wave in a mains power supply mode;

[0071] Fig. 13C This is a first working schematic diagram of the uninterruptible power supply provided by an embodiment of the present application in a battery power supply mode through a PFC boost circuit;

[0072] Fig.13D It is a first working schematic diagram of the uninterruptible power supply provided by an embodiment of the present application in a battery power supply mode through a battery bidirectional circuit;

[0073] Fig.14 It is a second working schematic diagram of the uninterruptible power supply provided by the embodiment of the present application in the battery power supply mode through the PFC boost circuit;

[0074] Fig.15A It is a third working schematic diagram of the uninterruptible power supply provided by the embodiment of the present application in the battery power supply mode through the PFC boost circuit;

[0075] Fig. 15B is a second working schematic diagram of the uninterruptible power supply provided by an embodiment of the present application in a battery power supply mode through a battery bidirectional circuit;

[0076] Fig. 15C It is a schematic diagram of the operation of the uninterruptible power supply provided in an embodiment of the present application through a battery bidirectional circuit in a mains power supply mode. DETAILED DESCRIPTION

[0077] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[0078] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, wholes, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or combinations thereof.

[0079] It should also be understood that the term “and / or” used in the specification and appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0080] In addition, in the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0081] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0082] In addition, the “plurality” mentioned in the embodiments of the present application should be interpreted as two or more.

[0083] The inventors have found that when the UPS is powered by batteries, usually only the battery bidirectional circuit is used for power supply, and the PFC boost circuit does not work and is only used when powered by AC power, resulting in the need for the AC power supply and battery power supply circuits to be designed and operated independently, resulting in low circuit utilization in the UPS. In addition, when powered by batteries, since the DC bus is powered only by the battery bidirectional circuit, the power of the battery bidirectional circuit needs to meet the rated power of the UPS, and the power of the electronic components constituting the battery bidirectional circuit is relatively large, which is not conducive to reducing the volume and cost. Therefore, it is necessary to consider an uninterruptible power supply.

[0084] In order to increase the reuse rate of circuits in UPS and reduce the volume and cost, in the implementation mode of the present application, a battery pack and a PFC boost circuit are connected. When the battery is powered, the battery pack can be discharged to the DC bus through the PFC boost circuit, so that the PFC boost circuit can be used when powered by the battery and the AC power. Moreover, when the battery is powered, the DC bus is powered by the PFC boost circuit and the battery bidirectional circuit at the same time. Compared with only rectifying and boosting by the battery bidirectional circuit, the power of the battery bidirectional circuit does not need to meet the rated power of the UPS, thereby reducing the volume and cost of the battery bidirectional circuit.

[0085] In order to make the purpose, technical solutions and advantages of the present application clearer, specific embodiments will be described below in conjunction with the accompanying drawings.

[0086] Figure 1 A schematic diagram of the structure of an uninterruptible power supply provided in an embodiment of the present application, the uninterruptible power supply comprising:

[0087] The PFC boost circuit has an input terminal for connecting to a mains input and one of the input terminals is connected to a target polarity terminal of a battery pack. The polarity terminal of the battery pack includes a positive electrode BAT+ and a negative electrode BAT-, and the target polarity terminal can be the positive electrode BAT+ of the battery pack or the negative electrode BAT- of the battery pack.

[0088] Here, the PFC boost circuit can rectify and boost the AC power input from the mains, convert it into DC power, and input it into the DC bus; the PFC boost circuit can also boost the DC power input from the battery pack and discharge it to the positive bus or negative bus of the DC bus.

[0089] In addition, the battery pack can be built into the UPS or placed outside the UPS.

[0090] A DC bus, whose input end is connected to the output end of the PFC boost circuit; wherein the DC bus includes a positive bus +BUS, a negative bus -BUS and a neutral line N; a positive capacitor C11 is connected between the positive bus +BUS and the neutral line N, and a negative capacitor C12 is connected between the neutral line N and the negative bus -BUS. Here, the "positive" and "negative" in the positive capacitor and the negative capacitor are only for the convenience of distinguishing the two capacitors, and are not a limitation on the capacitors.

[0091] The conversion circuit has an input end connected to the output end of the DC bus and an output end connected to the load. Here, the conversion circuit can be a direct current (DC)-to-DC conversion circuit or an inverter circuit. When the current required by the load is direct current, a DC-DC conversion circuit can be used to convert the direct current and provide it to the load; when the current required by the load is alternating current, an inverter circuit can be used to convert the direct current into alternating current and provide it to the load.

[0092] The battery bidirectional circuit has a first port D01 on the battery side for connecting to a target polarity end, and a second port D02 for connecting to another polarity end of the battery pack; a third port D03 on the bus side for connecting to a positive bus +BUS or a negative bus -BUS, and a fourth port D04 for connecting to a neutral line N.

[0093] In this embodiment, in the AC power supply mode, the battery bidirectional circuit can charge the DC bus to the battery pack; in the battery power supply mode, the battery bidirectional circuit can discharge the electric energy of the battery pack to the DC bus.

[0094] Here, when the target polarity end is the positive electrode BAT+ of the battery pack, the first port D01 of the battery bidirectional circuit is connected to the positive electrode BAT+ of the battery pack, and the second port D02 is connected to the negative electrode BAT- of the battery pack; when the target polarity end is the negative electrode BAT- of the battery pack, the first port D01 of the battery bidirectional circuit is connected to the negative electrode BAT- of the battery pack, and the second port D02 is connected to the positive electrode BAT+ of the battery pack.

[0095] The balancing bridge circuit is connected to the DC bus and is used to balance the voltage difference between the positive capacitor C11 and the negative capacitor C12, thereby realizing the power regulation between the positive bus +BUS and the negative bus -BUS, so that the DC bus meets the power needs of the load.

[0096] Optionally, in the battery power supply mode, one of the input terminals of the PFC boost circuit is connected to the target polarity terminal of the battery pack, so that the battery pack can be discharged to the positive bus +BUS or the negative bus -BUS through the PFC boost circuit, that is, the battery pack is charged with the positive capacitor C11 or the negative capacitor C12; the first port D01 and the second port D02 on the battery side of the battery bidirectional circuit are connected to the BAT+ and the negative electrode BAT- of the battery pack, the third port D03 on the bus side is connected to the positive bus +BUS or the negative bus -BUS, and the fourth port D04 is connected to the neutral line N, so that the battery pack can be discharged to the positive bus +BUS or the negative bus -BUS through the battery bidirectional circuit, that is, the battery pack is charged with the positive capacitor C11 or the negative capacitor C12.

[0097] Specifically, the uninterruptible power supply may further include a controller, which is specifically used to: in the battery power supply mode, control the battery pack to charge the positive capacitor C11 or the negative capacitor C12 through the PFC boost circuit, and the battery pack to charge the positive capacitor C11 or the negative capacitor C12 through the battery bidirectional circuit.

[0098] From the above, it can be seen that the battery pack boosts half of the DC bus through the PFC boost circuit and boosts half of the DC bus through the battery bidirectional circuit. Compared with the conventional solution of boosting the battery pack voltage to the entire bus voltage, under the same boost ratio, the present invention reduces the voltage of the battery pack and improves battery safety.

[0099] Furthermore, in order to solve the problem of possible imbalance between the positive capacitor C11 and the negative capacitor C12, especially when the battery pack charges the same half bus through the PFC boost voltage and the battery two-wire circuit, the positive capacitor C11 and the negative capacitor C12 need to be balanced through a balancing bridge.

[0100] Optionally, the uninterruptible power supply further comprises a controller, the controller being used for:

[0101] When the AC power input from the mains is normal, the AC power input from the mains is used for power supply, that is, the mains power supply mode, which can be specifically: controlling the PFC boost circuit to convert the AC power input from the mains into DC power, and controlling the conversion circuit to convert the DC power and provide it to the load; in addition, the battery bidirectional circuit is also controlled to charge the battery pack.

[0102] When the AC power input from the mains fails, the DC power input from the battery pack is used for power supply, that is, the battery power supply mode, which can be specifically: controlling the electric energy stored in the battery pack to be input into the PFC boost circuit, and controlling the PFC boost circuit to convert the electric energy input from the battery pack into the positive bus +BUS or the negative bus -BUS; controlling the electric energy stored in the battery pack to be input into the battery bidirectional circuit, and controlling the battery bidirectional circuit to discharge the electric energy input from the battery pack to the positive bus +BUS or the negative bus -BUS; and controlling the balancing bridge circuit to balance the voltage difference between the positive capacitor C11 and the negative capacitor C12, and controlling the conversion circuit to convert the DC power and provide it to the load.

[0103] The embodiment of the present application connects the battery pack and the PFC boost circuit, so that when there is a fault in the AC power input at the mains input terminal, that is, in the battery state, the electric energy of the battery pack can be discharged to the DC bus through the PFC boost circuit; the battery pack is also connected to the positive bus or the negative bus in the DC bus through the battery bidirectional circuit, and the electric energy in the battery pack is discharged to the DC bus through the battery bidirectional circuit. The DC bus can be powered by the PFC boost circuit and the battery bidirectional circuit at the same time. Compared with only rectifying and boosting by the battery bidirectional circuit, the power of the battery bidirectional circuit can be reduced, so that the power of the battery bidirectional circuit does not need to meet the rated power of the UPS, thereby reducing the volume and cost of the battery bidirectional circuit. Moreover, the DC bus is powered by the PFC boost circuit and the battery bidirectional circuit at the same time, so that the PFC boost circuit and the battery bidirectional circuit can be fully utilized when powered by AC power and battery, thereby improving the reuse rate of the circuit; in addition, since the PFC boost circuit and the battery bidirectional circuit are both connected to one polarity end in the DC bus when the battery pack is used for boosting, half of the DC bus is boosted, and there is an imbalance problem between the positive bus and the negative bus in the DC bus, a balancing bridge circuit is connected to the DC bus, and the balancing bridge circuit is used to balance the voltage difference between the positive capacitor and the negative capacitor.

[0104] The following is an introduction to the battery bidirectional circuit, PFC boost circuit, balanced bridge circuit and conversion circuit in the uninterruptible power supply.

[0105] There are two main structures of battery bidirectional circuits: Figure 2A The structural diagram of the first battery bidirectional circuit is shown, and Figure 2B The structural schematic diagram of the second battery bidirectional circuit is shown.

[0106] In some embodiments, see Figure 2AThe structural schematic diagram of the first battery bidirectional circuit is shown, and the battery bidirectional circuit includes a first inductor L1, a first switch tube Q1 and a second switch tube Q2; the first end of the first inductor L1 serves as the first port D01 of the battery bidirectional circuit; the second end of the first inductor L1 is respectively connected to the first end of the first switch tube Q1 and the first end of the second switch tube Q2; the second end of the first switch tube Q1 serves as the second port D02 and the fourth port D04 of the battery bidirectional circuit (it can be seen that the second port D02 and the fourth port D04 of the battery bidirectional circuit are directly connected); the second end of the second switch tube Q2 serves as the third port D03 of the battery bidirectional circuit.

[0107] When the target polarity end is the positive terminal BAT+ of the battery pack, refer to Figure 3 The structural schematic diagram of the uninterruptible power supply with multiplexing positive bus to boost the positive bus is shown, the first port D01 of the battery bidirectional circuit is connected to the positive electrode BAT+ of the battery pack, and the third port D03 of the battery bidirectional circuit is connected to the positive bus +BUS.

[0108] At this time, the battery pack can boost the positive bus +BUS through the battery bidirectional circuit; and the positive electrode BAT+ of the battery pack is connected to an input end of the PFC boost circuit, and the battery pack can reuse the positive bus +BUS through the PFC boost circuit. That is, the battery pack boosts the positive bus +BUS through both the battery bidirectional circuit and the PFC boost circuit to charge the positive capacitor C11.

[0109] When the target polarity terminal is the negative electrode BAT- of the battery pack, refer to Figure 4 The structural schematic diagram of the uninterruptible power supply with multiplexed negative bus to boost negative bus is shown, the first port D01 of the battery bidirectional circuit is connected to the negative electrode BAT- of the battery pack, and the third port D03 of the battery bidirectional circuit is connected to the negative bus -BUS.

[0110] At this time, the battery pack can boost the negative bus -BUS through the battery bidirectional circuit; and the negative electrode BAT- of the battery pack is connected to an input end of the PFC boost circuit, and the battery pack can reuse the negative bus -BUS through the PFC boost circuit. That is, the battery pack boosts the negative bus -BUS through both the battery bidirectional circuit and the PFC boost circuit to charge the negative capacitor C12.

[0111] In addition, using Figure 2A In the battery bidirectional circuit shown in the figure, the battery pack is used to boost the same half bus through the battery bidirectional circuit and the PFC boost circuit, and only one capacitor between the bus bars is charged, which aggravates the imbalance between the positive bus +BUS and the negative bus -BUS, and between the positive capacitor C11 and the negative capacitor C12. Therefore, a balancing bridge circuit is also needed here to balance the voltage difference between the positive and negative bus bars, so as to make the UPS work more stably.

[0112] In other embodiments, see Figure 2B The structural schematic diagram of the second battery bidirectional circuit shown in the figure, the battery bidirectional circuit includes a first inductor L1, a first switch tube Q1 and a second switch tube Q2; the first end of the first switch tube Q1 serves as the first port D01 of the battery bidirectional circuit; the second end of the first switch tube Q1 is respectively connected to the first end of the first inductor L1 and the first end of the second switch tube Q2; the second end of the first inductor L1 serves as the second port D02 and the fourth port D04 of the battery bidirectional circuit (it can be seen that the second port D02 and the fourth port D04 of the battery bidirectional circuit are directly connected); the second end of the second switch tube Q2 serves as the third port D03 of the battery bidirectional circuit.

[0113] When the target polarity end is the positive electrode BAT+ of the battery pack, the third port D03 of the battery bidirectional circuit is connected to the negative bus -BUS.

[0114] At this time, the positive electrode BAT+ of the battery pack is connected to an input end of the PFC boost circuit, and the battery pack can reuse the positive bus +BUS through the PFC boost circuit; and the battery pack can boost the negative bus -BUS through the battery bidirectional circuit. That is, the positive bus +BUS is boosted by the PFC boost circuit to charge the positive capacitor C11, and the battery pack boosts the negative bus -BUS through the battery bidirectional circuit to charge the negative capacitor C12.

[0115] When the target polarity terminal is the negative electrode BAT- of the battery pack, refer to Figure 5 The structural schematic diagram of the uninterruptible power supply that reuses the negative bus to boost the positive bus is shown, the first port D01 of the battery bidirectional circuit is connected to the negative electrode BAT- of the battery pack, and the third port D03 of the battery bidirectional circuit is connected to the positive bus +BUS.

[0116] At this time, the negative electrode BAT- of the battery pack is connected to an input terminal of the PFC boost circuit, and the battery pack can reuse the negative bus -BUS through the PFC boost circuit; and the battery pack can boost the positive bus +BUS through the battery bidirectional circuit. That is, the battery pack boosts the negative bus -BUS through the PFC boost circuit to charge the negative capacitor C12, and boosts the positive bus +BUS through the battery bidirectional circuit to charge the positive capacitor C11.

[0117] In this embodiment, the third port on the bus side of the battery bidirectional circuit is connected to the positive bus or the negative bus, and the fourth port is connected to the neutral line, that is, the battery pack is discharged only to the positive bus or the negative bus through the battery bidirectional circuit, and only half of the DC bus is boosted, instead of being discharged to the positive bus and the negative bus. This can reduce the voltage that the battery bidirectional circuit needs to increase, and only needs to meet the voltage of half the bus, thereby reducing the voltage stress of the battery bidirectional circuit, thereby reducing the specifications of each component in the battery bidirectional circuit, and reducing the volume and cost of the battery bidirectional circuit.

[0118] Optional, see Figure 6As shown in the circuit structure diagram of the first single-phase multiplexed positive bus boosting uninterruptible power supply, the battery bidirectional circuit may further include a first capacitor C1 connected between the first port and the second port of the battery bidirectional circuit.

[0119] See also Figure 7 As shown in the circuit structure diagram of the second single-phase multiplexed positive bus boosting uninterruptible power supply, the battery bidirectional circuit may also include a first Hall device HALL1, and the second end of the first inductor L1 may be connected to the first switch tube Q1 and the second switch tube Q2 through the first Hall device HALL1.

[0120] In some embodiments, see Figure 1 The uninterruptible power supply also includes a first switch K1, a second switch K2 and a third switch K3; the first end of the first switch K1 is used to connect to the mains input, and the second end of the first switch K1 is connected to the input end of the PFC boost circuit; the first end of the second switch K2 is used to connect to the target polarity end of the battery pack, and the second end of the second switch K2 is connected to an input end of the PFC boost circuit; the first end of the third switch K3 is used to connect to the positive electrode BAT+ of the battery pack, and the second end of the third switch K3 is connected to a port in the battery bidirectional circuit for connecting to the positive electrode of the battery pack.

[0121] In this embodiment, by controlling the on and off of the first switch K1, the second switch K2 and the third switch K3, the power supply mode of the uninterruptible power supply can be switched to realize mains power supply and battery power supply.

[0122] When the first switch K1 is turned on and the second switch K2 is turned off, the AC input from the mains can be converted into DC by the PFC boost circuit, and then the DC is converted by the conversion circuit and provided to the load. If the third switch K3 is turned on, the battery pack can also be charged.

[0123] When the first switch K1 is disconnected, the second switch K2 is turned on, and the third switch K3 is turned on, the battery pack is discharged, and the electric energy input by the battery pack can be converted into power and input to the positive bus or the negative bus through the PFC boost circuit; at the same time, the electric energy input by the battery pack can be discharged to the positive bus or the negative bus through the battery bidirectional circuit.

[0124] The above article introduces two types of battery bidirectional circuits and switches in uninterruptible power supplies. The following will continue to introduce the PFC boost circuit. The circuit structure diagram of the uninterruptible power supply with a single-phase multiplexed positive bus boosting positive bus is used for illustration. There are two main structures of the PFC boost circuit, namely Figure 6 The circuit structure diagram of the first single-phase multiplexed positive bus boosting positive bus shown in FIG. Figure 7 The circuit structure diagram of the second single-phase multiplexed positive bus boosting positive bus is shown.

[0125] In some embodiments, see Figure 6 The circuit structure diagram of the first single-phase multiplexed positive bus boosting uninterruptible power supply of the positive bus is shown, the PFC boost circuit includes a second inductor L2, a first diode D1, a second diode D2, a third switch tube Q3 and a fourth switch tube Q4; the first end of the second inductor L2 serves as the input end of the PFC boost circuit; the second end of the second inductor L2 is respectively connected to the anode of the first diode D1, the cathode of the second diode D2 and the collector of the third switch tube Q3; the cathode of the first diode D1 is connected to the positive bus; the anode of the second diode D2 is connected to the negative bus; the emitter of the third switch tube Q3 is connected to the emitter of the fourth switch tube Q4, and the collector of the fourth switch tube Q4 is used to connect the neutral line.

[0126] Here, the PFC boost circuit further includes a first current transformer CT1 , a first end of the first current transformer CT1 serves as an input end of the PFC boost circuit, and a second end of the first current transformer CT1 is connected to a first end of the second inductor L2 .

[0127] In addition, the first switch K1 may include a first relay RLY1, a second relay RLY2 and a first resistor R1; after the second relay RLY2 is connected in series with the first resistor R1, it is connected in parallel with the first relay RLY1, which can reduce the starting current and loss.

[0128] Correspondingly, the second switch K2 may include a third relay, a fourth relay and a second resistor; the fourth relay is connected in series with the second resistor and then connected in parallel with the third relay. The third switch K3 may include a fifth relay RLY5, a sixth relay RLY6 and a third resistor R3; the sixth relay RLY6 is connected in series with the third resistor R3 and then connected in parallel with the fifth relay RLY5.

[0129] In some other embodiments, referring to the circuit structure diagram of the second single-phase multiplexed positive bus boosting uninterruptible power supply of the positive bus shown in 7, the first switch K1 includes a first thyristor SCR1 and a second thyristor SCR2, and the second switch K2 includes a third thyristor SCR3; the PFC boost circuit includes a second inductor L2, a third inductor L3, a first diode D1, a second diode D2, a third switch tube Q3 and a fourth switch tube Q4.

[0130] The anode of the first thyristor SCR1 is connected to the cathode of the second thyristor SCR2 and serves as the first end of the first switch K1; the cathode of the first thyristor SCR1 serves as the first port of the second end of the first switch K1 and is connected to the first end of the second inductor L2; the anode of the second thyristor SCR2 serves as the second port of the second end of the first switch K1 and is connected to the first end of the third inductor L3.

[0131] Here, when the gate of the first thyristor SCR1 is subjected to a forward voltage, when the anode potential of the first thyristor SCR1 is higher than the cathode potential, the first thyristor SCR1 is turned on and can transmit current; when the cathode potential of the first thyristor SCR1 is higher than the anode potential, the first thyristor SCR1 is reversely blocked and cannot transmit current. That is, when the AC power input from the mains is a positive half-wave, it can be input into the PFC boost circuit through the first thyristor SCR1.

[0132] Correspondingly, when the gate of the second thyristor SCR2 is subjected to a forward voltage, when the anode potential of the second thyristor SCR2 is higher than the cathode potential, the second thyristor SCR2 is turned on and can transmit current; when the cathode potential of the second thyristor SCR2 is higher than the anode potential, the second thyristor SCR2 is reversely blocked and cannot transmit current. That is, when the AC input of the mains is a negative half-wave, the second thyristor SCR2 is turned on, and the PFC boost circuit is connected to the mains input.

[0133] In the PFC boost circuit, the second end of the second inductor L2 is respectively connected to the anode of the first diode D1 and the collector of the third switch tube Q3; the cathode of the first diode D1 is connected to the positive bus +BUS; the emitter of the third switch tube Q3 is used to connect to the neutral line N; the second end of the third inductor L3 is respectively connected to the emitter of the fourth switch tube Q4 and the cathode of the second diode D2; the anode of the second diode D2 is connected to the negative bus -BUS; the collector of the fourth switch tube Q4 is used to connect to the neutral line N.

[0134] In the second switch K2, when the target polarity end is the positive electrode BAT+ of the battery pack, the anode of the third thyristor SCR3 serves as the first end of the second switch K2, and the cathode of the third thyristor SCR3 is connected to the first end of the second inductor L2. When the gate of the third thyristor SCR3 is subjected to a forward voltage, the battery pack is discharged, the anode potential of the third thyristor SCR3 is higher than the cathode potential, the third thyristor SCR3 is turned on, and the battery pack is connected to the PFC boost circuit.

[0135] When the target polarity end is the negative electrode BAT- of the battery pack, the cathode of the third thyristor SCR3 serves as the first end of the second switch K2, and the anode of the third thyristor SCR3 is connected to the first end of the third inductor L3. When the gate of the third thyristor SCR3 is subjected to a forward voltage, the battery pack is discharged, the anode potential of the third thyristor SCR3 is higher than the cathode potential, the third thyristor SCR3 is turned on, and the battery pack is connected to the PFC boost circuit.

[0136] Here, the PFC boost circuit also includes a first current transformer CT1 and a second current transformer CT2, the first end of the first current transformer CT1 serves as an input end of the PFC boost circuit, and the second end of the first current transformer CT1 is connected to the first end of the second inductor L2; the first end of the second current transformer CT2 serves as an input end of the PFC boost circuit, and the second end of the second current transformer CT2 is connected to the first end of the third inductor L3.

[0137] In some embodiments, Figure 6 and Figure 7 As shown, the balanced bridge circuit includes a fourth inductor L4, a seventh switch tube Q7 and an eighth switch tube Q8; the first end of the fourth inductor L4 is used to connect to the neutral line N, and the second end of the fourth inductor L4 is respectively connected to the emitter of the seventh switch tube Q7 and the collector of the eighth switch tube; the collector of the seventh switch tube Q7 is used to connect to the positive bus +BUS; the emitter of the eighth switch tube Q8 is used to connect to the negative bus -BUS.

[0138] In this embodiment, the positive capacitor C11 stores the electric energy between the positive bus +BUS and the neutral line N, and the negative capacitor C12 stores the electric energy between the negative bus -BUS and the neutral line N. When the battery is powered, since the PFC boost circuit reuses the positive bus +BUS or the negative bus -BUS, and the battery bidirectional circuit boosts the positive bus +BUS or the negative bus -BUS, the electric energy stored in the positive capacitor C11 and the negative capacitor C12 may be different. Therefore, a balanced bridge circuit can be used to transfer the electric energy of the capacitor with high stored electric energy to the capacitor with low stored electric energy, so that the electric energy stored in the positive capacitor C11 and the negative capacitor C12 are equal, and the voltage difference between the positive capacitor C1 and the negative capacitor C12 is balanced.

[0139] In actual use, when the conversion circuit is an inverter circuit, the electric energy stored in the positive capacitor C11 and the negative capacitor C12 can be converted into alternating current. Specifically, the inverter circuit converts the electric energy stored in the positive capacitor C11 into the positive half-wave of the output alternating current, and the inverter circuit converts the electric energy stored in the negative capacitor C12 into the negative half-wave of the output alternating current.

[0140] In some embodiments, Figure 6 and Figure 7 As shown, the inverter circuit may adopt an I-type inverter circuit. The inverter circuit includes a third diode D3, a fourth diode D4, a first inverter switch tube Q71, a second inverter switch tube Q72, a third inverter switch tube Q73 and a fourth inverter switch tube Q74.

[0141] The anode of the third diode D3 is connected to the neutral line N, and the cathode of the third diode D3 is connected to the emitter of the first inverter switch tube Q71 and the collector of the second inverter switch tube Q72; the collector of the first inverter switch tube Q71 is connected to the positive bus +BUS, and the emitter of the second inverter switch tube Q72 serves as the output end of the inverter circuit.

[0142] The cathode of the fourth diode D4 is connected to the neutral line N, and the anode of the fourth diode D4 is connected to the emitter of the third inverter switch tube Q73 and the collector of the fourth inverter switch tube Q74; the collector of the third inverter switch tube Q73 serves as the output end of the inverter circuit, and the emitter of the fourth inverter switch tube Q74 is connected to the negative bus -BUS.

[0143] Optionally, the output end of the inverter circuit may be connected to a load via a fifth inductor L5.

[0144] Two current transformers may also be connected between the fifth inductor L5 and the load, such as the fourth current transformer CT4 and the fifth current transformer CT5 in the figure.

[0145] In addition, a fourth capacitor C4 may be connected between the live wire and the neutral wire of the output AC power to filter out high-frequency signals in the output AC power and prevent high-frequency interference from leaking from the output AC power and interfering with the load.

[0146] In some embodiments, the uninterruptible power supply also includes a bypass and a fourth switch K4; the input end of the bypass is used to connect to the AC input, and the output end of the bypass is connected to the first end of the fourth switch K4; the second end of the fourth switch K4 is connected to the output end of the conversion circuit, and the third end of the fourth switch K4 is used to connect to the load.

[0147] By controlling the fourth switch K4, when bypass operation is required, the first end of the fourth switch K4 can be controlled to be turned on to turn on the bypass, and the AC power input from the mains can be directly provided to the load through the bypass; when the UPS is used normally, the second end of the fourth switch K4 can be controlled to be turned on to turn off the bypass.

[0148] See also Figure 8 The circuit structure diagram of the third type of uninterruptible power supply with single-phase multiplexed positive bus and positive bus boost is shown. In some embodiments, a common mode inductor can also be set in the uninterruptible power supply. The uninterruptible power supply also includes a first common mode inductor Lc1, a second common mode inductor Lc2 and a third common mode inductor Lc3. The AC power input from the mains is connected to the PFC boost circuit through the first common mode inductor Lc1; the battery pack is connected to one input end of the PFC boost circuit through the second common mode inductor Lc2, and the battery pack is connected to the battery bidirectional circuit through the second common mode inductor Lc2; the conversion circuit supplies power to the load through the third common mode inductor Lc3.

[0149] See also Figure 9-12The AC power input from the mains may be three-phase AC power, such as phase A, phase B, and phase C.

[0150] In some embodiments of the present application, see Fig. 9 The circuit structure diagram of the first three-phase multiplexed positive bus boosting uninterruptible power supply is shown in FIG. Fig.11 The circuit structure diagram of the uninterruptible power supply of the three-phase multiplexing negative bus boosting negative bus shown in FIG. Fig.12 The circuit structure diagram of the uninterruptible power supply of the three-phase multiplexing positive bus boosting negative bus is shown.

[0151] The uninterruptible power supply comprises three first switches, three second switches and three PFC boost circuits, and each phase of the three-phase alternating current corresponds to a first switch, a second switch and a PFC boost circuit.

[0152] For each phase, the first end of the first switch of the phase is used to connect the alternating current of the phase, and the second end of the first switch of the phase is connected to the input end of the PFC boost circuit of the phase; an input end of the corresponding PFC boost circuit is also connected to the second end of the second switch of the phase, and the output end of the corresponding PFC boost circuit is connected to the bus.

[0153] In this embodiment, in the mains power supply mode, each PFC boost circuit converts the corresponding one-phase AC power received into DC power and inputs the DC power into the DC bus.

[0154] In the battery power supply mode, the battery pack is connected to each phase of the PFC boost circuit through three second switches, and the three-phase PFC boost circuit can be used for power conversion at the same time. Therefore, in the battery power supply mode, the battery pack can be discharged through the three-phase PFC boost circuit and the battery bidirectional circuit, realizing four-way parallel discharge of the battery.

[0155] In addition, the topological structure in each PFC boost circuit can refer to the topological structure of single-phase alternating current, which will not be described in detail here.

[0156] In other embodiments, see Fig.10 The circuit structure diagram of the second three-phase multiplexed positive bus boosting uninterruptible power supply is shown. The mains input is three-phase AC power. The uninterruptible power supply includes three first switches K1. Each phase of the three-phase AC power corresponds to a first switch K1.

[0157] For each phase, the first end of the corresponding first switch K1 is used to connect the alternating current of the phase; the first port of the second end of the corresponding first switch K1 is connected to the first end of the second inductor L2, and the second port of the second end of the corresponding first switch K1 is connected to the first end of the third inductor L3.

[0158] In this embodiment, in the mains power supply mode, each phase of AC power is input into the PFC boost circuit through the corresponding first switch K1 , and the PFC boost circuit converts the received three-phase AC power into DC power and inputs it into the DC bus.

[0159] Here, by setting three first switches K1, the three-phase AC power can be input into one PFC boost circuit, without setting three PFC boost circuits, which can reduce the components of the PFC boost circuit, reduce the circuit volume, and reduce the cost.

[0160] The above introduces the specific structure of the uninterruptible power supply. Figure 6 Taking the first single-phase multiplexed positive bus boosting positive bus uninterruptible power supply as an example, the working principle and control method of the uninterruptible power supply are introduced.

[0161] Reference Figures 13A-13D In the embodiment of the present application, the uninterruptible power supply further includes a controller, and the controller is used to:

[0162] When the AC power input from the mains is normal, the uninterruptible power supply works in the mains power supply mode, and can control the first switch K1 to be turned on, the second switch K2 to be turned off, and the third switch K3 to be turned on; control the PFC boost circuit to convert the AC power input from the mains into DC power, control the conversion circuit to convert the DC power and provide it to the load; and control the battery bidirectional circuit to charge the battery pack.

[0163] The first switch K1 is turned on to connect the AC input with the PFC boost circuit, the third switch K3 is turned on to connect the battery pack with the battery bidirectional circuit, and the second switch is turned off to disconnect the battery pack from the PFC boost circuit.

[0164] See also Fig.13A The uninterruptible power supply shown is a working schematic diagram of the positive half-wave in the AC power supply mode. In the positive half-wave of the AC power, when the third switch tube Q3 is turned off, the current passes through the A path; when the third switch tube Q3 is turned on, the current passes through the B path.

[0165] See also Fig. 13B The working schematic diagram of the uninterruptible power supply in the negative half-wave under the AC power supply mode is shown. In the negative half-wave of the AC power, when the fourth switch tube Q4 is turned off, the current passes through the A path; when the fourth switch tube Q4 is turned on, the current passes through the B path.

[0166] In addition, Fig.13A and Fig. 13B In the embodiment, when the second switch tube Q2 is turned on, the current charges the battery pack through the C path; when the second switch tube Q2 is turned off, the current charges the battery pack through the D path.

[0167] When the AC power input from the mains fails, the first switch K1 is controlled to be disconnected, the second switch K2 is controlled to be turned on, and the third switch K3 is controlled to be turned on; the electric energy stored in the battery pack is controlled to be input into the PFC boost circuit, and the PFC boost circuit is controlled to convert the electric energy input from the battery pack into the positive bus +BUS or the negative bus -BUS; the electric energy stored in the battery pack is controlled to be input into the battery bidirectional circuit, and the battery bidirectional circuit is controlled to discharge the electric energy input from the battery pack to the positive bus +BUS or the negative bus -BUS; and, the balancing bridge circuit is controlled to balance the voltage difference between the positive capacitor C11 and the negative capacitor C12, and the conversion circuit is controlled to convert the DC power and provide it to the load.

[0168] The second switch K2 is turned on to connect the battery pack with the PFC boost circuit, the third switch K3 is turned on to connect the battery pack with the battery bidirectional circuit, and the first switch K1 is turned off to disconnect the AC input from the PFC boost circuit.

[0169] See also Fig. 13C The uninterruptible power supply shown in the figure is in the battery power supply mode through the PFC boost circuit's first working schematic diagram, when the third switch tube Q3 is turned off, the current passes through the A path; when the third switch tube Q3 is turned on, the current passes through the B path, and the battery pack discharges the stored electrical energy to the positive bus +BUS through the PFC boost circuit.

[0170] See also Fig.13D The uninterruptible power supply shown in the figure is in the battery power supply mode through the first working schematic diagram of the battery bidirectional circuit. The battery bidirectional circuit switches from the charging state to the discharging state. When the first switch tube Q1 is turned on, the current passes through the A path. When the first switch tube Q1 is turned off, the current passes through the B path to discharge the electrical energy stored in the battery pack to the positive bus +BUS.

[0171] Here, only an uninterruptible power supply that reuses the positive bus to boost the positive bus is used for explanation. When other uninterruptible power supplies in the above embodiments of the present application are used, the electrical energy stored in the battery pack is also discharged to the corresponding positive bus or negative bus.

[0172] For example, in Figure 4 In the corresponding uninterruptible power supply, in the battery power supply mode, the battery pack discharges the stored electric energy to the negative bus -BUS through the PFC boost circuit, and the battery bidirectional circuit discharges the stored electric energy of the battery pack to the negative bus -BUS.

[0173] Among them, see Fig.14 The second working schematic diagram of the uninterruptible power supply in the battery power supply mode through the PFC boost circuit is shown. When the fourth switch tube Q4 is turned on, the current passes through the A path; when the fourth switch tube Q4 is turned off, the current passes through the B path. The working process of the uninterruptible power supply in the battery power supply mode through the battery bidirectional circuit can refer to the above Fig.13Dshown.

[0174] exist Figure 5 In the corresponding uninterruptible power supply, in the battery power supply mode, the battery pack discharges the stored electric energy to the negative bus -BUS through the PFC boost circuit, and the battery bidirectional circuit discharges the stored electric energy of the battery pack to the positive bus +BUS.

[0175] Among them, see Fig.15A The third working schematic diagram of the uninterruptible power supply through the PFC boost circuit in the battery power supply mode shown, when the fourth switch tube Q4 is turned on, the current passes through the A path; when the fourth switch tube Q4 is turned off, the current passes through the B path.

[0176] See also Fig. 15B The uninterruptible power supply shown in the figure is in a second working schematic diagram of a battery bidirectional circuit in a battery power supply mode. When the first switch tube Q1 is turned on, the current passes through the A path, and the battery pack charges the first inductor L1; when the first switch tube Q1 is turned off, the current passes through the B path, and the first inductor L1 is discharged to charge the positive capacitor C11.

[0177] Accordingly, in the mains power supply mode, the battery pack is charged through the battery bidirectional circuit. For details, please refer to Fig. 15C When the second switch tube Q2 is turned on, the current passes through the A path, and the positive capacitor C11 charges the first inductor L1; when the second switch tube Q2 is turned off, the current passes through the B path, and the first inductor L1 is discharged to charge the battery pack.

[0178] In addition, when the uninterruptible power supply needs to use a bypass, the first switch K1 is controlled to be disconnected, the second switch K2 is controlled to be disconnected, the third switch K3 is controlled to be disconnected, and the first end of the fourth switch K4 is turned on, and the bypass is controlled to provide the AC power input by the mains to the load.

[0179] The controller in the embodiment of the present application may be physically multiple controllers, which respectively control different circuits in the uninterruptible power supply. For example, the uninterruptible power supply may include a first controller and a second controller, the first controller is used to control the PFC boost circuit and the battery bidirectional circuit, and the second controller is used to control the conversion circuit. Accordingly, the first controller may also control the first switch K1, the second switch K2, the third switch K3 and the fourth switch K4. Specifically, one controller may be a control chip.

[0180] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0181] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. An uninterruptible power supply, characterized in that: include: A PFC boost circuit, whose input terminal is used to connect to the mains input and one of the input terminals is connected to the target polarity terminal of the battery pack; A DC bus, whose input end is connected to the output end of the PFC boost circuit; wherein the DC bus includes a positive bus, a negative bus and a neutral line; a positive capacitor is connected between the positive bus and the neutral line, and a negative capacitor is connected between the neutral line and the negative bus; A conversion circuit, whose input end is connected to the output end of the DC bus, and whose output end is used to connect to a load; A battery bidirectional circuit, wherein the first port corresponding to the battery side is used to connect to the target polarity end, and the second port is used to connect to the other polarity end of the battery pack; the third port corresponding to the bus side is used to connect to the positive bus or negative bus, and the fourth port is used to connect to the neutral line; A balancing bridge circuit is connected to the DC bus and is used to balance the voltage difference between the positive capacitor and the negative capacitor.

2. The uninterruptible power supply according to claim 1, characterized in that: The battery bidirectional circuit includes a first inductor, a first switch tube and a second switch tube; The first end of the first inductor serves as the first port of the battery bidirectional circuit; The second end of the first inductor is respectively connected to the first end of the first switch tube and the first end of the second switch tube; The second end of the first switch tube serves as the second port and the fourth port of the battery bidirectional circuit; The second end of the second switch tube serves as the third port of the battery bidirectional circuit; When the target polarity end is the positive electrode of the battery pack, the third port of the battery bidirectional circuit is connected to the positive bus; When the target polarity end is the negative electrode of the battery pack, the third port of the battery bidirectional circuit is connected to the negative bus.

3. The uninterruptible power supply according to claim 1, characterized in that: The battery bidirectional circuit includes a first inductor, a first switch tube and a second switch tube; The first end of the first switch tube serves as the first port of the battery bidirectional circuit; The second end of the first switch tube is respectively connected to the first end of the first inductor and the first end of the second switch tube; The second end of the first inductor serves as the second port and the fourth port of the battery bidirectional circuit; The second end of the second switch tube serves as the third port of the battery bidirectional circuit; When the target polarity end is the positive electrode of the battery pack, the third port of the battery bidirectional circuit is connected to the negative bus; When the target polarity end is the negative electrode of the battery pack, the third port of the battery bidirectional circuit is connected to the positive bus.

4. The uninterruptible power supply according to any one of claims 1 to 3, characterized in that: The uninterruptible power supply also includes a controller, which is used to: in a battery power supply mode, control the battery pack to charge the positive capacitor or the negative capacitor through a PFC boost circuit, and the battery pack to charge the positive capacitor or the negative capacitor through a battery bidirectional circuit.

5. The uninterruptible power supply according to claim 4, characterized in that: The uninterruptible power supply also includes a first switch, a second switch and a third switch; The first end of the first switch is used to connect to the mains input, and the second end of the first switch is connected to the input end of the PFC boost circuit; The first end of the second switch is used to connect the target polarity end of the battery pack, and the second end of the second switch is connected to the input end of the PFC boost circuit; The first end of the third switch is used to connect to the positive electrode of the battery pack, and the second end of the third switch is connected to a port in the battery bidirectional circuit that is used to connect to the positive electrode of the battery pack.

6. The uninterruptible power supply according to any one of claims 1 to 3, characterized in that: The PFC boost circuit includes a second inductor, a first diode, a second diode, a third switch tube and a fourth switch tube; The first end of the second inductor serves as the input end of the PFC boost circuit; the second end of the second inductor is respectively connected to the anode of the first diode, the cathode of the second diode and the collector of the third switch tube; The cathode of the first diode is connected to the positive bus; The anode of the second diode is connected to the negative bus; The emitter of the third switch tube is connected to the emitter of the fourth switch tube, and the collector of the fourth switch tube is used to connect to the neutral line.

7. The uninterruptible power supply according to claim 5, characterized in that: The first switch includes a first thyristor and a second thyristor, and the second switch includes a third thyristor; The PFC boost circuit includes a second inductor, a third inductor, a first diode, a second diode, a third switch tube and a fourth switch tube; The anode of the first thyristor and the cathode of the second thyristor are connected and serve as the first end of the first switch; the cathode of the first thyristor serves as the first port of the second end of the first switch and is connected to the first end of the second inductor; the anode of the second thyristor serves as the second port of the second end of the first switch and is connected to the first end of the third inductor; The second end of the second inductor is connected to the anode of the first diode and the collector of the third switch tube respectively; the cathode of the first diode is connected to the positive bus; the emitter of the third switch tube is used to connect to the neutral line; The second end of the third inductor is connected to the emitter of the fourth switch tube and the cathode of the second diode respectively; the anode of the second diode is connected to the negative bus; the collector of the fourth switch tube is used to connect to the neutral line; When the target polarity end is the positive electrode of the battery pack, the anode of the third thyristor serves as the first end of the second switch, and the cathode of the third thyristor is connected to the first end of the second inductor; when the target polarity end is the negative electrode of the battery pack, the cathode of the third thyristor serves as the first end of the second switch, and the anode of the third thyristor is connected to the first end of the third inductor.

8. The uninterruptible power supply according to claim 5, characterized in that: The controller is used to: When the AC power input from the mains is normal, the first switch is controlled to be turned on, the second switch is turned off, and the third switch is controlled to be turned on; the PFC boost circuit is controlled to convert the AC power input from the mains into DC power, and the conversion circuit is controlled to convert the DC power into AC power to provide to the load; and the battery bidirectional circuit is controlled to charge the battery pack; When the AC power input from the mains fails, the first switch is controlled to be disconnected, the second switch is controlled to be turned on, and the third switch is controlled to be turned on; the electric energy stored in the battery pack is controlled to be input into the PFC boost circuit, and the PFC boost circuit is controlled to perform power conversion on the electric energy input from the battery pack and input it into the positive bus or the negative bus; the electric energy stored in the battery pack is controlled to be input into the battery bidirectional circuit, and the battery bidirectional circuit is controlled to discharge the electric energy input from the battery pack to the positive bus or the negative bus; and, the balancing bridge circuit is controlled to balance the voltage difference between the positive capacitor and the negative capacitor, and the conversion circuit is controlled to convert the DC power into AC power and provide it to the load.

9. The uninterruptible power supply according to claim 5, characterized in that: The mains input is three-phase alternating current, the uninterruptible power supply comprises three first switches, three second switches and three PFC boost circuits, each phase of the three-phase alternating current corresponds to a first switch, a second switch and a PFC boost circuit; For each phase, a first end of the first switch of the phase is used to connect the AC power of the phase, and a second end of the first switch of the phase is connected to an input end of the PFC boost circuit of the phase; An input end of the corresponding PFC boost circuit is also connected to the second end of the second switch of the phase, and an output end of the corresponding PFC boost circuit is connected to the bus.

10. The uninterruptible power supply according to claim 7, characterized in that: The mains inputs three-phase alternating current, and the uninterruptible power supply comprises three first switches, each phase of the three-phase alternating current corresponds to a first switch; For each phase, the first end of the corresponding first switch is used to connect the alternating current of the phase; the first port of the second end of the corresponding first switch is connected to the first end of the second inductor, and the second port of the second end of the corresponding first switch is connected to the first end of the third inductor.

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