Uninterruptible power supply for double battery packs

Abstract

The invention provides an uninterruptible power supply for double battery packs. A battery pack of the uninterruptible power supply is a double-battery pack, and the uninterruptible power supply comprises a PFC booster circuit, the input end of which is used for being connected with commercial power input, and the input end of which is also used for being connected with the positive electrode of the double-battery pack through a first switch and being connected with the negative electrode of the double-battery pack through a second switch; 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 battery bidirectional circuit of which a port corresponding to a battery side is used for connecting the double battery packs, and a port corresponding to a bus side is used for connecting the direct current bus; in the battery power supply mode, the double battery packs charge the positive capacitor and the negative capacitor through the battery bidirectional circuit, and when the capacity difference value of the two battery packs in the double battery packs is larger than a preset difference value, the battery pack with the high capacity in the double battery packs charges the positive capacitor or the negative capacitor through the PFC booster circuit. According to the invention, each battery pack of the UPS can be controlled to discharge reasonably by using the battery pack with high capacity.

Description

Technical Field

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

[0002] The basic structure of an uninterruptible power supply (UPS) includes a power factor correction (PFC) boost circuit, a battery bidirectional circuit, and a conversion circuit. 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 powered continuously.

[0003] Multiple battery packs can be set up in a UPS to supply power simultaneously. Since the capacities of the battery packs may be different, during the battery discharge process, when the low-capacity battery pack is discharged, the high-capacity battery pack still has remaining capacity. However, in order to prevent the battery pack from being overcharged or over-discharged, the overall battery pack composed of the individual battery packs will stop discharging, resulting in the inability to fully utilize the full capacity of the high-capacity battery pack. Summary of the invention

[0004] The embodiment of the present application provides an uninterruptible power supply for dual battery packs, so as to fully utilize the battery packs with high capacity and control the reasonable discharge of each battery pack of the UPS.

[0005] In a first aspect, an embodiment of the present application provides an uninterruptible power supply for a dual battery pack, wherein the battery pack of the uninterruptible power supply is a dual battery pack, and the dual battery pack includes two battery packs connected in series; the uninterruptible power supply includes:

[0006] A PFC boost circuit, whose input end is used to connect to the mains input, and whose input end is also used to connect to the positive electrode of the dual battery pack through a first switch, and to connect to the negative electrode of the dual battery pack through a second switch;

[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 and the second port corresponding to the battery side are respectively used to connect the positive electrode and the negative electrode of the dual battery pack, the third port and the fourth port corresponding to the bus side are respectively used to connect the two polarity ends of the DC bus, and the fifth port is used to connect the neutral line and the neutral line of the dual battery pack;

[0010] A balancing bridge circuit, connected to the DC bus, for balancing the voltage difference between the positive capacitor and the negative capacitor;

[0011] In the battery power supply mode, the dual battery pack charges the positive capacitor and the negative capacitor through a battery bidirectional circuit, and when the capacity difference between the two battery packs in the dual battery pack is greater than a preset difference, the battery pack with higher capacity in the dual battery pack charges the positive capacitor or the negative capacitor through a PFC boost circuit.

[0012] In one possible implementation, in a battery power supply mode, when the battery group with higher capacity in the dual battery group is the first battery group corresponding to the positive electrode of the dual battery group, the first switch is turned on; when the battery group with higher capacity in the dual battery group is the second battery group corresponding to the negative electrode of the dual battery group, the second switch is turned on.

[0013] In a possible implementation, the uninterruptible power supply further includes a controller, a third switch, and a fourth switch;

[0014] The input end of the PFC boost circuit is connected to the mains input through the third switch, and the battery bidirectional circuit is connected to the dual battery pack through the fourth switch;

[0015] The controller is used to:

[0016] When the AC power input from the mains fails, the third switch is controlled to be disconnected and the fourth switch is turned on to enter the battery power supply mode; the battery power supply mode is specifically: the electric energy stored in the dual 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 dual battery pack to the DC bus; 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 and provide it to the load;

[0017] and, determining whether a capacity difference between two battery packs in the dual battery pack is greater than a preset difference, and determining a battery pack with a higher capacity in the dual battery pack;

[0018] If the capacity difference between the two battery groups in the dual battery group is greater than a preset difference, and the battery group with a higher capacity in the dual battery group is the first battery group, controlling the first switch to be turned on and the second switch to be turned off;

[0019] If the capacity difference between the two battery groups in the dual battery group is greater than a preset difference, and the battery group with a higher capacity in the dual battery group is the second battery group, the first switch is controlled to be disconnected, and the second switch is controlled to be turned on.

[0020] In a possible implementation manner, the controller is further configured to:

[0021] When the AC power input from the mains is normal, controlling the first switch to be disconnected, the second switch to be disconnected, the third switch to be turned on, and the fourth switch to be turned on, to enter the mains power supply mode;

[0022] When the AC power input from the mains fails, the third switch is controlled to be disconnected and the fourth switch is turned on to enter the battery power supply mode; the battery power supply mode also includes: if the capacity difference between the two battery packs in the dual battery pack is less than or equal to the preset difference, the first switch is controlled to be disconnected, and the second switch is controlled to be disconnected.

[0023] In a possible implementation, the PFC boost circuit includes a third inductor, a first diode, a second diode, a fifth switch tube, and a sixth switch tube;

[0024] The first end of the third inductor serves as the input end of the PFC boost circuit; the second end of the third inductor is respectively connected to the anode of the first diode, the cathode of the second diode and the collector of the fifth switch tube;

[0025] The cathode of the first diode is used to connect the positive bus;

[0026] The anode of the second diode is used to connect the negative bus;

[0027] The emitter of the fifth switch tube is connected to the emitter of the sixth switch tube, and the collector of the sixth switch tube is used to connect to the neutral line.

[0028] In a possible implementation, the mains input is three-phase alternating current, the uninterruptible power supply includes three first switches, three second switches, three third switches and three PFC boost circuits, and each phase of the three-phase alternating current corresponds to a first switch, a second switch, a third switch and a PFC boost circuit;

[0029] For each phase, the first end of the corresponding third switch is used to connect the AC power of the phase, and the second end of the corresponding third switch is connected to the input end of the PFC boost circuit of the phase;

[0030] The input end of the corresponding PFC boost circuit is also connected to the second end of the first switch of the phase and the second end of the second switch of the phase, and the output end of the corresponding PFC boost circuit is connected to the DC bus.

[0031] In a possible implementation, the third switch includes a first thyristor and a second thyristor, the first switch includes the third thyristor, and the second switch includes a fourth thyristor;

[0032] The PFC boost circuit includes a third inductor, a fourth inductor, a first diode, a second diode, a fifth switch tube and a sixth switch tube;

[0033] The anode of the first thyristor and the cathode of the second thyristor are connected and serve as the first end of the third switch; the cathode of the first thyristor serves as the first port of the second end of the third switch and is connected to the first end of the third inductor; the anode of the second thyristor serves as the second port of the second end of the third switch and is connected to the first end of the fourth inductor;

[0034] The second end of the third inductor is connected to the anode of the first diode and the collector of the fifth switch tube respectively; the cathode of the first diode is connected to the positive bus; the emitter of the fifth switch tube is used to connect to the neutral line;

[0035] The second end of the fourth inductor is connected to the emitter of the sixth 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 sixth switch tube is used to connect to the neutral line;

[0036] The anode of the third thyristor serves as the first end of the first switch; the cathode of the third thyristor serves as the second end of the first switch and is connected to the first end of the third inductor;

[0037] The cathode of the fourth thyristor serves as the first end of the second switch; the anode of the fourth thyristor serves as the second end of the second switch and is connected to the first end of the fourth inductor.

[0038] In a possible implementation, the mains input is three-phase alternating current, the uninterruptible power supply includes three third switches, and each phase of the three-phase alternating current corresponds to one third switch;

[0039] For each phase, the first end of the corresponding third switch is used to connect the alternating current of the phase, the first port of the second end of the corresponding third switch is connected to the first end of the third inductor, and the second port of the second end of the corresponding third switch is connected to the first end of the fourth inductor.

[0040] In a possible implementation, the battery bidirectional circuit includes a first inductor, a second inductor, a first switch tube, a second switch tube, a third switch tube and a fourth switch tube;

[0041] The first end of the first inductor serves as the first port of the battery bidirectional circuit, and is used to connect to the positive electrode of the dual battery pack;

[0042] The second end of the first inductor is respectively connected to the emitter of the first switch tube and the collector of the second switch tube;

[0043] The collector of the first switch tube serves as the third port of the battery bidirectional circuit, and is used to connect the positive bus;

[0044] The emitter of the second switch tube is connected to the collector of the third switch tube, and the emitter of the second switch tube serves as the fifth port of the battery bidirectional circuit, and is used to connect the neutral line of the dual battery group and the neutral line;

[0045] The first end of the second inductor serves as the second port of the battery bidirectional circuit, and is used to connect to the negative electrode of the dual battery pack;

[0046] The second end of the second inductor is respectively connected to the emitter of the third switch tube and the collector of the fourth switch tube;

[0047] The emitter of the fourth switch tube serves as the fourth port of the battery bidirectional circuit and is used to connect to the negative bus.

[0048] In a second aspect, an embodiment of the present application provides an uninterruptible power supply for a dual battery pack, wherein the battery pack of the uninterruptible power supply is a dual battery pack, wherein the dual battery pack includes a first battery pack and a second battery pack connected in series, wherein the capacity of the first battery pack is greater than the capacity of the second battery pack; the uninterruptible power supply includes:

[0049] A PFC boost circuit, whose input end is used to connect the mains input and the target polarity end of the dual battery group; wherein the target polarity end is the polarity end of the dual battery group corresponding to the first battery group;

[0050] 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;

[0051] 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;

[0052] A battery bidirectional circuit, wherein the first port and the second port corresponding to the battery side are respectively used to connect the positive electrode and the negative electrode of the dual battery pack, the third port and the fourth port corresponding to the bus side are respectively used to connect the two polarity ends of the DC bus, and the fifth port is used to connect the neutral line and the neutral line of the dual battery pack;

[0053] A balancing bridge circuit, connected to the DC bus, for balancing the voltage difference between the positive capacitor and the negative capacitor;

[0054] In the battery power supply mode, the dual battery pack charges the positive capacitor and the negative capacitor through a battery bidirectional circuit, and when the capacity difference between the two battery packs in the dual battery pack is greater than a preset difference, the first battery pack charges the positive capacitor or the negative capacitor through a PFC boost circuit.

[0055] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0056] In the embodiment of the present application, the positive and negative electrodes of the dual battery group are connected to the PFC boost circuit respectively through the first switch and the second switch. When there is a fault in the AC power input at the mains input terminal, that is, in the battery power supply mode, the battery group with high capacity in the dual battery group is connected to the DC bus through the PFC boost circuit, so that the battery group with high capacity in the dual battery group is discharged to the DC bus through the PFC boost circuit; at the same time, the dual battery group is connected to the DC bus through the battery bidirectional circuit, so that the two battery groups in the dual battery group can be discharged to the DC bus through the battery bidirectional circuit. Among them, the battery group with high capacity in the dual battery group is discharged to the DC bus through the PFC boost circuit and the battery bidirectional circuit respectively, while the battery group with low capacity in the dual battery group is only discharged to the bus through the battery bidirectional circuit, which can speed up the discharge speed of the battery group with high capacity, make the two battery groups in the dual battery group tend to balance, reduce the capacity difference between the battery groups, and make full use of the battery group with high capacity to achieve reasonable discharge of the dual battery group. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] 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.

[0058] Figure 1 is a schematic diagram of the structure of an uninterruptible power supply for a dual battery pack provided in an embodiment of the present application;

[0059] Figure 2 is a schematic diagram of a first state of an uninterruptible power supply provided by an embodiment of the present application;

[0060] Figure 3 is a schematic diagram of a second state of the uninterruptible power supply provided by an embodiment of the present application;

[0061] Figure 4 This is a circuit structure diagram of a first single-phase uninterruptible power supply provided in an embodiment of the present application;

[0062] Figure 5 This is a circuit structure diagram of a first three-phase uninterruptible power supply provided in an embodiment of the present application;

[0063] Figure 6 is a circuit structure diagram of a second single-phase uninterruptible power supply provided in an embodiment of the present application;

[0064] Figure 7 is a circuit structure diagram of a second three-phase uninterruptible power supply provided in an embodiment of the present application;

[0065] Figure 8 It is a circuit structure diagram of a third single-phase uninterruptible power supply provided in an embodiment of the present application;

[0066] Fig. 9 It is a schematic diagram of the operation of an uninterruptible power supply provided by an embodiment of the present application in a battery-powered mode through a PFC boost circuit;

[0067] Fig.10 It is a schematic diagram of another uninterruptible power supply provided by an embodiment of the present application working in a battery power supply mode through a PFC boost circuit;

[0068] Fig.11 It is a schematic diagram of the operation of the uninterruptible power supply provided by an embodiment of the present application through a battery bidirectional circuit in a battery power supply mode. DETAILED DESCRIPTION

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] In addition, the “plurality” mentioned in the embodiments of the present application should be interpreted as two or more.

[0075] The inventors have found that multiple battery packs can be set in the UPS for battery power supply, which usually requires that the capacity of each battery pack is equal, or the capacity difference between the battery packs is less than a preset difference. However, in the actual operation of the UPS, the capacity difference between the battery packs is often greater than the preset difference, such as mixing new and old batteries. Taking two battery packs as an example, during the battery discharge process, the battery with low capacity will be emptied first, while the battery pack with high capacity still has residual capacity. In order to prevent the battery pack from being overcharged or over-discharged, the discharge will be stopped at this time, which will result in the inability to fully utilize the full capacity of the battery pack with high capacity. Therefore, it is necessary to consider an uninterruptible power supply.

[0076] In order to make full use of the high-capacity battery pack and control the reasonable discharge of each battery pack, in the implementation mode of the present application, the positive and negative electrodes of the dual battery pack are respectively connected to the PFC boost circuit through switches. In the battery power supply mode, the switch corresponding to the high-capacity battery pack in the dual battery pack is closed, and the high-capacity battery pack can be discharged to the DC bus through the PFC boost circuit, and the two battery packs in the dual battery pack can also be discharged to the DC bus through the battery bidirectional circuit, so that the high-capacity battery pack in the dual battery pack can be discharged through the PFC boost circuit and the battery bidirectional circuit at the same time, thereby accelerating the discharge speed of the high-capacity battery pack, while the low-capacity battery pack is discharged only through the battery bidirectional circuit, which can make the energy of the two battery packs in the dual battery pack tend to be balanced and reduce the capacity difference between the battery packs, thereby making full use of the high-capacity battery pack and realizing the reasonable discharge of the dual battery pack.

[0077] 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.

[0078] Figure 1 A schematic diagram of the structure of an uninterruptible power supply for a dual battery pack provided in an embodiment of the present application, wherein the battery pack of the uninterruptible power supply is a dual battery pack, and the dual battery pack includes two battery packs connected in series. The dual battery pack can be built into the UPS or placed outside the UPS.

[0079] Here, multiple batteries can be connected to the UPS, and two battery groups can be formed by dividing all the connected batteries, that is, each battery group in the dual battery group can also be composed of multiple batteries. For example, eight batteries can be connected to the UPS, four batteries form a battery group, and two battery groups are connected in series to form a dual battery group.

[0080] Likewise, when four battery packs are connected to the UPS, the four battery packs can be divided to form a dual battery pack.

[0081] The present application provides an uninterruptible power supply for a dual battery pack, comprising:

[0082] The PFC boost circuit has an input end for connecting to the mains input. 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.

[0083] In addition, the input end of the PFC boost circuit is also used to connect the positive electrode BAT+ of the dual battery group through the first switch K1, and to connect the negative electrode BAT- of the dual battery group through the second switch K2. When the first switch K1 is closed, the positive electrode BAT+ of the dual battery group is connected to the PFC boost circuit, and the electric energy of the battery group corresponding to the positive electrode of the dual battery group can be input to the PFC boost circuit; when the second switch K2 is closed, the negative electrode BAT- of the dual battery group is connected to the PFC boost circuit, and the electric energy of the battery group corresponding to the negative electrode of the dual battery group can be input to the PFC boost circuit. The PFC boost circuit can boost the DC power input by the battery group, thereby discharging to the positive bus or negative bus of the DC bus.

[0084] 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.

[0085] 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.

[0086] The battery bidirectional circuit has a first port D01 and a second port D02 on the battery side corresponding to the positive electrode BAT+ and the negative electrode BAT- of the dual battery pack, respectively, a third port D03 and a fourth port D04 on the bus side corresponding to the two polarity ends of the DC bus (positive bus +BUS and negative bus -BUS), respectively, and a fifth port D05 for connecting the neutral line N and the neutral line of the dual battery pack.

[0087] In the AC power supply mode, the battery bidirectional circuit can charge the DC bus to the dual battery pack; in the battery power supply mode, the battery bidirectional circuit can discharge the electrical energy of the dual battery pack to the DC bus.

[0088] 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.

[0089] Here, since the high-capacity battery pack is connected to one polarity end of the DC bus through the PFC boost circuit to boost half of the DC bus, and the dual battery pack is connected to the two polarity ends of the DC bus through the battery bidirectional circuit to boost the entire DC bus, an imbalance problem occurs between the positive and negative buses in the DC bus. Accordingly, there is a voltage difference between the positive capacitor C11 and the negative capacitor C12. By connecting the balancing bridge circuit to the DC bus, the positive capacitor C11 and the negative capacitor C12 can be balanced by the balancing bridge circuit, thereby ensuring the normal and safe use of the UPS.

[0090] In the battery power supply mode, the first port D01 and the second port D02 of the battery bidirectional circuit are connected to the positive electrode BAT+ and the negative electrode BAT- of the dual battery pack, the third port D03 and the fourth port D04 are connected to the positive bus +BUS and the negative bus -BUS, and the fifth port is connected to the neutral line N, so that the dual battery pack can discharge to the DC bus through the battery bidirectional circuit, that is, the dual battery pack charges the positive capacitor C11 and the negative capacitor C12 through the battery bidirectional circuit.

[0091] When the capacity difference between the two battery groups in the dual battery group is greater than the preset difference, the dual battery group can only be discharged through the battery bidirectional circuit, and the battery group with higher capacity in the dual battery group cannot be fully utilized. Therefore, the battery group with higher capacity in the dual battery group can be connected to the PFC boost circuit to discharge to the positive bus +BUS or the negative bus -BUS, that is, the battery group with higher capacity in the dual battery group charges the positive capacitor C11 or the negative capacitor C12 through the PFC boost circuit.

[0092] In the embodiment of the present application, the positive and negative electrodes of the dual battery group are connected to the PFC boost circuit respectively through the first switch and the second switch. When there is a fault in the AC power input at the mains input terminal, that is, in the battery power supply mode, the battery group with high capacity in the dual battery group is connected to the DC bus through the PFC boost circuit, so that the battery group with high capacity in the dual battery group is discharged to the DC bus through the PFC boost circuit; at the same time, the dual battery group is connected to the DC bus through the battery bidirectional circuit, so that the two battery groups in the dual battery group can be discharged to the DC bus through the battery bidirectional circuit. Among them, the battery group with high capacity in the dual battery group is discharged to the DC bus through the PFC boost circuit and the battery bidirectional circuit respectively, while the battery group with low capacity in the dual battery group is only discharged to the bus through the battery bidirectional circuit, which can speed up the discharge speed of the battery group with high capacity, make the two battery groups in the dual battery group tend to balance, reduce the capacity difference between the battery groups, and make full use of the battery group with high capacity to achieve reasonable discharge of the dual battery group. In addition, the dual battery pack boosts the entire DC bus through a battery bidirectional circuit, and the battery pack with higher capacity in the dual battery pack also boosts the positive bus +BUS or the negative bus -BUS through a PFC boost circuit, resulting in an unbalanced boost between the positive and negative buses, causing a voltage difference between the positive capacitor C11 and the negative capacitor C12. Therefore, a balancing bridge is also connected to the DC bus to balance the positive capacitor C11 and the negative capacitor C12 through the balancing bridge.

[0093] There are three main working modes of UPS, namely AC power supply mode, battery power supply mode and bypass mode. The following is an introduction to the above three working modes respectively.

[0094] Since this solution mainly considers the difference in capacity between the two battery packs in the dual battery pack, the battery power supply mode of the UPS will be described below.

[0095] In some embodiments, the battery group corresponding to the positive electrode BAT+ in the dual battery group can be used as the first battery group, and the battery group corresponding to the negative electrode BAT- can be used as the second battery group.

[0096] In the battery power supply mode, when the battery pack with higher capacity in the dual battery pack is the first battery pack corresponding to the positive electrode BAT+ of the dual battery pack, such as Figure 2 As shown, the first switch K1 is turned on and the second switch K2 is turned off (in Figure 2 The second switch K2 in the disconnected state is not shown in the figure, which can connect the positive electrode BAT+ of the dual battery group with the PFC boost circuit, so that the first battery group can be discharged to the positive bus +BUS through the PFC boost circuit, thereby accelerating the discharge speed of the first battery group and promoting the balance between the first battery group and the second battery group.

[0097] When the battery pack with the highest capacity in the dual battery pack is the second battery pack corresponding to the negative electrode BAT- of the dual battery pack, such as Figure 3 As shown, the second switch K2 is turned on and the first switch K1 is turned off (at Figure 3 The first switch K1 in the disconnected state is not shown in the figure, which can connect the negative electrode BAT- of the dual battery group with the PFC boost circuit, and the second battery group can be discharged to the negative bus -BUS through the PFC boost circuit, thereby accelerating the discharge speed of the second battery group and promoting the balance between the first battery group and the second battery group.

[0098] In this embodiment, in the battery power supply mode, the first switch K1 is turned on and the second switch K2 is turned on. This may be because the UPS receives a control instruction or signal of the first switch K1 or the second switch K2; or because the UPS receives an instruction on the capacity difference between the two battery packs in the dual battery pack and controls the corresponding switches to be turned on according to the received instruction; or because the UPS detects that there is a capacity difference between the two battery packs in the dual battery pack, makes a judgment, and controls the corresponding switches to be turned on.

[0099] In addition, if there are staff on site at the UPS, the staff can also manually control the switch to turn on the first switch K1 or the second switch K2. For example, when replacing the dual battery pack of the UPS with a dual battery pack that mixes new and old batteries, the staff knows the battery pack with a higher capacity and can perform manual control in the battery power supply mode.

[0100] The above-mentioned control method of switch conduction is only an example and is not intended to be limiting. Any method that can achieve the switch conduction between the battery pack with a higher capacity in the dual battery pack and the PFC boost circuit is acceptable.

[0101] In some embodiments, the uninterruptible power supply further includes a controller, a third switch K3 and a fourth switch K4; the input end of the PFC boost circuit is connected to the AC input through the third switch K3, and the battery bidirectional circuit is connected to the dual battery pack through the fourth switch K4.

[0102] Here, the controller can control the UPS, for example, control switches in the UPS, switch working modes, etc.

[0103] The controller can be used to:

[0104] When the AC power input from the mains fails, the third switch K3 is controlled to be disconnected and the fourth switch K4 is turned on, entering the battery power supply mode. When the third switch K3 is disconnected, the input end of the PFC boost circuit is disconnected from the mains input; when the fourth switch K4 is closed, the dual battery pack is connected to the battery bidirectional circuit, and the dual battery pack can be discharged to the DC bus through the battery bidirectional circuit.

[0105] The battery power supply mode is specifically as follows: controlling the electric energy stored in the dual battery pack to be input into the battery bidirectional circuit, and controlling the battery bidirectional circuit to discharge the electric energy input by the dual battery pack to the DC bus; 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.

[0106] And, it is determined whether the capacity difference between the two battery groups in the dual battery group is greater than a preset difference, and the battery group with higher capacity in the dual battery group is determined.

[0107] If the capacity difference between the two battery groups in the dual battery group is greater than the preset difference, and the battery group with higher capacity in the dual battery group is the first battery group, the first switch K1 is controlled to be turned on, and the second switch K2 is controlled to be turned off.

[0108] If the capacity difference between the two battery groups in the dual battery group is greater than the preset difference, and the battery group with higher capacity in the dual battery group is the second battery group, the first switch K1 is controlled to be disconnected, and the second switch K2 is controlled to be turned on.

[0109] In the battery power supply mode, the controller can be used to detect and judge the two battery packs in the dual battery pack, determine the battery pack with higher capacity in the dual battery pack, and determine whether the battery pack with higher capacity needs to be discharged faster.

[0110] In the above process, "controlling the electric energy stored in the dual battery pack to be input into the battery bidirectional circuit, and controlling the battery bidirectional circuit to discharge the electric energy input by the dual battery pack to the DC bus", and "determining whether the capacity difference between the two battery packs in the dual battery pack is greater than the preset difference, and determining the battery pack with higher capacity in the dual battery pack" can be carried out simultaneously or in steps.

[0111] Furthermore, when the AC power input from the mains fails, the third switch is controlled to be disconnected and the fourth switch is turned on to enter the battery power supply mode; the battery power supply mode also includes: if the capacity difference between the two battery packs in the dual battery pack is less than or equal to the preset difference, it means that the capacity difference between the two battery packs in the dual battery pack is small, and the two battery packs can be used in a balanced manner without speeding up the discharge speed of one of the battery packs, then the first switch is controlled to be disconnected, and the second switch is controlled to be disconnected, and there is no need to connect the dual battery pack to the PFC boost circuit.

[0112] The above are various situations of UPS in battery power supply mode. The following will continue to introduce the AC power supply mode of UPS.

[0113] In some embodiments, the controller is further used to: when the AC power input from the mains is normal, control the first switch K1 to be disconnected, the second switch K2 to be disconnected, the third switch K3 to be turned on, and the fourth switch K4 to be turned on, so as to enter the mains power supply mode.

[0114] The first switch K1 and the second switch K2 are disconnected, so that the dual battery pack is disconnected from the PFC boost circuit. The third switch K3 is turned on, so that the AC power input from the mains is input to the DC bus through the PFC boost circuit, so that the load is powered by the mains input. The fourth switch K4 is turned on, and the dual battery pack can be charged through the battery bidirectional circuit to ensure that the UPS works in the battery power supply mode.

[0115] In addition, the UPS operation mode also includes a bypass mode. Figure 4 The circuit structure diagram of the first single-phase uninterruptible power supply shown in the figure, the uninterruptible power supply also includes a bypass and a fifth switch K5; the input end of the bypass is used to connect to the mains input, and the output end of the bypass is connected to the first end of the fifth switch K5; the second end of the fifth switch K5 is connected to the output end of the conversion circuit, and the third end of the fifth switch K5 is used to connect to the load.

[0116] By controlling the fifth switch K5, when bypass operation is required, the first end of the fifth switch K5 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 fifth switch K5 can be controlled to be turned on to turn off the bypass.

[0117] In addition, the controller 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.

[0118] The above article introduces the overall structure and working mode of UPS. The following article will continue to introduce the PFC boost circuit, battery bidirectional circuit, balance bridge circuit and conversion circuit in UPS respectively.

[0119] In some embodiments, see Figure 4 The circuit structure diagram of the first single-phase uninterruptible power supply shown in the figure, the PFC boost circuit includes a third inductor L3, a first diode D1, a second diode D2, a fifth switch tube Q5 and a sixth switch tube Q6; the first end of the third inductor L3 serves as the input end of the PFC boost circuit; the second end of the third inductor L3 is respectively connected to the anode of the first diode D1, the cathode of the second diode D2 and the collector of the fifth switch tube; the cathode of the first diode D1 is used to connect to the positive bus +BUS; the anode of the second diode D2 is used to connect to the negative bus -BUS; the emitter of the fifth switch tube Q5 is connected to the emitter of the sixth switch tube, and the collector of the sixth switch tube Q6 is used to connect to the neutral line N.

[0120] Here, if Figure 5 As shown, 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.

[0121] In addition, if Figure 4 As shown, the third switch K3 may include a first relay RLY1, a second relay RLY2 and a first resistor R1; the second relay RLY2 is connected in series with the first resistor R1 and then connected in parallel with the first relay RLY1, which can reduce the starting current and loss.

[0122] Correspondingly, the fourth switch K4 includes a third relay RLY3, a fourth relay RLY4 and a second resistor R2; the fourth relay RLY4 is connected in series with the second resistor R2 and then connected in parallel with the third relay RLY3.

[0123] In the mains power supply mode, the AC power input by the mains can be three-phase AC power.

[0124] Optional, see Figure 5 The circuit structure diagram of the first three-phase uninterruptible power supply is shown. When the mains input is three-phase AC power, the uninterruptible power supply may include three first switches K1, three second switches K2, three third switches K3 and three PFC boost circuits. Each phase of the three-phase AC power corresponds to a first switch K1, a second switch K2, a third switch K3 and a PFC boost circuit.

[0125] For each phase, the first end of the corresponding third switch is used to connect the AC power of the phase, and the second end of the corresponding third switch is connected to the input end of the PFC boost circuit of the phase.

[0126] The input end of the corresponding PFC boost circuit is also connected to the second end of the first switch of the phase and the second end of the second switch of the phase, and the output end of the corresponding PFC boost circuit is connected to the DC bus.

[0127] 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.

[0128] Since a first switch K1 and a second switch K2 are respectively set for each phase, in the battery power supply mode, the dual battery pack can be connected to the PFC boost circuit of each phase through three first switches K1 or three second switches K2, 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 dual battery pack can be discharged through the three-phase PFC boost circuit and the battery bidirectional circuit, thereby realizing four-way parallel discharge of the battery.

[0129] In other embodiments, see Figure 6 In the circuit structure diagram of the second single-phase uninterruptible power supply shown in FIG. 1 , the third switch K3 may include a first thyristor SCR1 and a second thyristor SCR2, the first switch K1 may include a third thyristor SCR3, and the second switch K2 may include a fourth thyristor SCR4. The PFC boost circuit includes a third inductor L3, a fourth inductor L4, a first diode D1, a second diode D2, a fifth switch tube Q5, and a sixth switch tube Q6.

[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 third switch K3; the cathode of the first thyristor SCR1 serves as the first port of the second end of the third switch K3 and is connected to the first end of the third inductor L3; the anode of the second thyristor SCR2 serves as the second port of the second end of the third switch K3 and is connected to the first end of the fourth inductor L4.

[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 third inductor L3 is respectively connected to the anode of the first diode D1 and the collector of the fifth switch tube Q5; the cathode of the first diode D1 is connected to the positive bus +BUS; the emitter of the fifth switch tube Q5 is used to connect to the neutral line N; the second end of the fourth inductor L4 is respectively connected to the emitter of the sixth switch tube Q6 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 sixth switch tube Q6 is used to connect to the neutral line N.

[0134] In the first switch K1, the anode of the third thyristor SCR3 serves as the first end of the first switch K1; the cathode of the third thyristor SCR3 serves as the second end of the first switch K1, and 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 group corresponding to the positive electrode BAT+ of the dual battery group discharges, the anode potential of the third thyristor SCR3 is higher than the cathode potential, the third thyristor SCR3 is turned on, and the positive electrode BAT+ of the dual battery group is connected to the PFC boost circuit.

[0135] In the second switch K2, the cathode of the fourth thyristor SCR4 serves as the first end of the second switch K2; the anode of the fourth thyristor SCR4 serves as the second end of the second switch K2, and is connected to the first end of the fourth inductor L4. When the gate of the fourth thyristor SCR4 is subjected to a positive voltage, the battery group corresponding to the negative electrode BAT- of the dual battery group discharges, the anode potential of the fourth thyristor SCR4 is higher than the cathode potential, the fourth thyristor SCR4 is turned on, and the negative electrode BAT- of the dual battery group is connected to the PFC boost circuit.

[0136] Here, if Figure 7 As shown, 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 third inductor L3; 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 fourth inductor L4.

[0137] Optional, see Figure 7 As shown in the circuit structure diagram of the second three-phase uninterruptible power supply, when the mains input is three-phase alternating current, the uninterruptible power supply may include three third switches K3, and each phase of the three-phase alternating current corresponds to one third switch K3.

[0138] For each phase, the first end of the corresponding third switch K3 is used to connect the alternating current of the phase, the first port of the second end of the corresponding third switch K3 is connected to the first end of the third inductor L3, and the second port of the second end of the corresponding third switch K3 is connected to the first end of the fourth inductor L4.

[0139] In this embodiment, in the mains power supply mode, each phase of AC power is input into the PFC boost circuit through the corresponding third switch K3 , and the PFC boost circuit converts the received three-phase AC power into DC power and inputs it into the DC bus.

[0140] Here, by setting three third switches K3, 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.

[0141] The above embodiments introduce the specific structures of two PFC boost circuits. The specific structure of the battery bidirectional circuit will be described below. Figure 4-Figure 7 The battery bidirectional circuit shown in .

[0142] In some embodiments, Figure 4 As shown, the battery bidirectional circuit includes a first inductor L1, a second inductor L2, a first switch tube Q1, a second switch tube Q2, a third switch tube Q3 and a fourth switch tube Q4.

[0143] The first end of the first inductor L1 serves as the first port D01 of the battery bidirectional circuit, and is used to connect the positive electrode BAT+ of the dual battery pack; the second end of the first inductor L1 is respectively connected to the emitter of the first switch tube Q1 and the collector of the second switch tube Q2; the collector of the first switch tube Q1 serves as the third port D03 of the battery bidirectional circuit, and is used to connect the positive bus +BUS.

[0144] The emitter of the second switch tube Q2 is connected to the collector of the third switch tube Q3, and the emitter of the second switch tube Q2 serves as the fifth port D05 of the battery bidirectional circuit, which is used to connect the neutral line of the dual battery pack and the neutral line N in the DC bus (it can be seen that the fifth port D05 of the battery bidirectional circuit has two interfaces, and the neutral line of the dual battery pack and the neutral line N in the DC bus are connected).

[0145] The first end of the second inductor L2 serves as the second port D02 of the battery bidirectional circuit, and is used to connect the negative electrode BAT- of the dual battery pack; the second end of the second inductor L2 is respectively connected to the emitter of the third switch tube Q3 and the collector of the fourth switch tube Q4; the emitter of the fourth switch tube Q4 serves as the fourth port D04 of the battery bidirectional circuit, and is used to connect the negative bus -BUS.

[0146] Optional, see Figure 4 As shown in the circuit structure diagram of the first single-phase uninterruptible power supply, the battery bidirectional circuit may also include a first capacitor C1 and a second capacitor C2, the first capacitor C1 is connected between the first port D01 and the fifth port D05 of the battery bidirectional circuit, and the second capacitor C2 is connected between the second port D02 and the fifth port D05.

[0147] In addition, the battery bidirectional circuit may further include a first Hall device HALL1 and a second Hall device HALL2 , wherein the first Hall device HALL1 is connected between the first port D01 and the first inductor L1 , and the second Hall device HALL2 is connected between the second port D02 and the second inductor L2 .

[0148] In other embodiments, Figure 6 As shown, the battery bidirectional circuit includes a first inductor L1, a second inductor L2, a first switch tube Q1, a second switch tube Q2, a third switch tube Q3 and a fourth switch tube Q4.

[0149] The collector of the first switch tube Q1 serves as the first port D01 of the battery bidirectional circuit, which is used to connect the positive electrode BAT+ of the dual battery pack; the emitter of the first switch tube Q1 is connected to the first end of the first inductor L1 and the collector of the second switch tube Q2; the emitter of the second switch tube Q2 serves as the fourth port D04 of the battery bidirectional circuit, which is used to connect the negative bus -BUS.

[0150] The second end of the first inductor L1 is connected to the first end of the second inductor L2, and the connection point thereof serves as the fifth port D05 of the battery bidirectional circuit, which is used to connect the neutral line of the dual battery pack and the neutral line N in the DC bus (it can be seen that the fifth port D05 of the battery bidirectional circuit has two interfaces, and the neutral line of the dual battery pack and the neutral line N in the DC bus are connected).

[0151] The collector of the third switch tube Q3 serves as the second port D02 of the battery bidirectional circuit, and is used to connect the negative electrode BAT- of the dual battery pack; the emitter of the third switch tube Q3 is connected to the second end of the second inductor L2 and the collector of the fourth switch tube Q4; the emitter of the fourth switch tube Q4 serves as the third port D03 of the battery bidirectional circuit, and is used to connect the positive bus +BUS.

[0152] In this embodiment, the first inductor L1, the first switch tube Q1 and the second switch tube Q2 constitute a first circuit, and the first battery group corresponding to the positive electrode BAT+ of the dual battery group can charge the negative capacitor C12 through the first circuit; the second inductor L2, the third switch tube Q3 and the fourth switch tube Q4 constitute a second circuit, and the second battery group corresponding to the negative electrode BAT- of the dual battery group can charge the positive capacitor C11 through the second circuit.

[0153] Both of the above-mentioned circuits are circuits that can be stepped up or down. For example, when the voltage of the first battery group is greater than the voltage of the negative capacitor C12, in the battery power supply mode, the first battery group can step down the voltage through the first circuit to charge the negative capacitor C12. In the AC power supply mode, the negative capacitor C12 can step up the voltage through the first circuit to charge the first battery group.

[0154] Correspondingly, when the voltage of the second battery pack is greater than the voltage of the positive capacitor C11, in the battery power supply mode, the second battery pack can be stepped down through the second circuit to charge the positive capacitor C11, and in the AC power supply mode, the positive capacitor C11 can be stepped up through the second circuit to charge the second battery pack.

[0155] In some embodiments, Figure 4 As shown, the balanced bridge circuit includes a fifth inductor L5, a seventh switch tube Q7 and an eighth switch tube Q8; the first end of the fifth inductor L5 is used to connect to the neutral line N, and the second end of the fifth inductor L5 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.

[0156] 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. In the battery power supply mode, the battery pack with higher capacity in the dual battery pack is connected to the PFC boost circuit, the PFC boost circuit reuses the positive bus +BUS or the negative bus -BUS, the battery bidirectional circuit boosts the positive bus +BUS and the negative bus -BUS, the positive capacitor C11 and the negative capacitor C12 store different electric energies, therefore, it is necessary to use a balanced bridge circuit to transfer the electric energy of the capacitor with higher electric energy to the capacitor with lower 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.

[0157] In actual use, the conversion circuit converts the electric energy stored in the positive capacitor C11 and the negative capacitor C12 into the direct current or alternating current required by the load. When the load adopts alternating current, the conversion circuit is an inverter circuit, which can convert the electric energy stored in the positive capacitor C11 into the positive half-wave of the output alternating current, and convert the electric energy stored in the negative capacitor C12 into the negative half-wave of the output alternating current.

[0158] In some embodiments, Figure 4-Figure 7 As shown, when the conversion circuit is an inverter circuit, the inverter circuit can adopt an I-type inverter circuit. The inverter circuit includes a third diode D3, a fourth diode D4, a first inverter switch tube Q91, a second inverter switch tube Q92, a third inverter switch tube Q93 and a fourth inverter switch tube Q94.

[0159] 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 Q91 and the collector of the second inverter switch tube Q92; the collector of the first inverter switch tube Q91 is connected to the positive bus +BUS, and the emitter of the second inverter switch tube Q92 serves as the output end of the inverter circuit.

[0160] 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 Q93 and the collector of the fourth inverter switch tube Q94; the collector of the third inverter switch tube Q93 serves as the output end of the inverter circuit, and the emitter of the fourth inverter switch tube Q94 is connected to the negative bus -BUS.

[0161] Optionally, the output end of the inverter circuit may be connected to a load via a sixth inductor L6.

[0162] Two current transformers may also be connected between the sixth inductor L6 and the load, such as Figure 5 The fourth current transformer CT4 and the fifth current transformer CT5.

[0163] In addition, a fifth capacitor C5 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.

[0164] See also Figure 8 The circuit structure diagram of the third single-phase uninterruptible power supply shown in FIG. 1 shows that in some embodiments, a common-mode inductor can also be provided 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 dual battery pack is connected to one input end of the PFC boost circuit through the second common-mode inductor Lc2, and the dual 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.

[0165] The above describes the working mode and specific structure of an uninterruptible power supply for a dual battery pack provided by the present application. Figure 4 Taking the uninterruptible power supply shown in the figure as an example, the working process of the uninterruptible power supply in battery power supply mode is introduced.

[0166] When the mains input fails, the uninterruptible power supply is in battery power supply mode. Take the first battery pack corresponding to the positive electrode BAT+ of the dual battery pack with the higher capacity as an example for explanation. Fig. 9 The diagram shows a working diagram of an uninterruptible power supply through a PFC boost circuit in a battery power supply mode, wherein the first switch K1 is turned on, the second switch K2 is turned off, and when the fifth switch tube Q5 is turned off, the current passes through path A; when the fifth switch tube Q5 is turned on, the current passes through path B.

[0167] Accordingly, the battery pack with the highest capacity in the dual battery pack is the second battery pack corresponding to the negative electrode BAT- of the dual battery pack as an example for explanation, see Fig.10The schematic diagram of another uninterruptible power supply working in battery power supply mode through the PFC boost circuit is shown, the second switch K2 is turned on, the first switch K1 is turned off, when the sixth switch tube Q6 is turned on, the current passes through the A path; when the sixth switch tube Q6 is turned off, the current passes through the B path.

[0168] Also, see Fig.11 The uninterruptible power supply shown in the figure works in the battery power supply mode through the battery bidirectional circuit. The battery bidirectional circuit switches from the charging state to the discharging state, and discharges the electric energy stored in the dual battery pack to the DC bus. When the second switch tube Q2 and the third switch tube Q3 are turned on, the dual battery pack can charge the first inductor L1 and the second inductor L2. Fig.11 When the second switch tube Q2 and the third switch tube Q3 are turned off, the dual battery pack charges the positive capacitor C11 and the negative capacitor C12 through the battery bidirectional circuit, such as Fig.11 The A path in .

[0169] The following is another embodiment of an uninterruptible power supply for dual battery packs of the present application. For details not described in detail, reference may be made to the corresponding embodiment of the first uninterruptible power supply described above.

[0170] For the sake of convenience, only the parts related to the embodiments of the present application are shown, which are described in detail as follows:

[0171] The battery pack of the uninterruptible power supply is a double battery pack, which can be built into the UPS or placed outside the UPS.

[0172] The dual battery pack includes a first battery pack and a second battery pack connected in series, and the capacity of the first battery pack is greater than that of the second battery pack. Here, the difference between the capacity of the first battery pack and the capacity of the second battery pack is known, and when in use, the polarity end of the dual battery pack corresponding to the first battery pack with higher capacity can be directly connected to the input end of the PFC boost circuit.

[0173] See also Figure 2 The first state schematic diagram of the uninterruptible power supply shown in FIG. Figure 3 The second state schematic diagram of the uninterruptible power supply shown in the figure, an uninterruptible power supply for a dual battery pack provided in this embodiment includes:

[0174] The PFC boost circuit has an input end for connecting the mains input and the target polarity end of the dual battery pack; wherein the target polarity end is the polarity end of the dual battery pack corresponding to the first battery pack.

[0175] Here, the target polarity terminal is the positive electrode BAT+ or the negative electrode BAT- of the dual battery pack.

[0176] When the positive electrode of the first battery group serves as the positive electrode BAT+ of the dual battery group, the target polarity end is the positive electrode BAT+ of the dual battery group; when the negative electrode of the first battery group serves as the negative electrode BAT- of the dual battery group, the target polarity end is the negative electrode BAT- of the dual battery group.

[0177] 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.

[0178] The conversion circuit has an input end connected to the output end of the DC bus and an output end for connecting to a load.

[0179] The battery bidirectional circuit has a first port D01 and a second port D02 on the battery side corresponding to the positive electrode BAT+ and the negative electrode BAT- of the dual battery pack, respectively, a third port D03 and a fourth port D04 on the bus side corresponding to the positive electrode +BUS and the negative bus -BUS, respectively, and a fifth port D05 for connecting the neutral line N and the neutral line of the dual battery pack.

[0180] 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.

[0181] In battery power supply mode, the dual battery pack charges the positive capacitor C11 and the negative capacitor C12 through the battery bidirectional circuit, and when the capacity difference between the two battery packs in the dual battery pack is greater than the preset difference, the first battery pack charges the positive capacitor C11 or the negative capacitor C12 through the PFC boost circuit.

[0182] In this embodiment, it has been predetermined that the capacity of the first battery group is greater than that of the second battery group. In order to speed up the discharge speed of the first battery group with larger capacity, in the battery power supply mode, the polarity ends of the dual battery group corresponding to the first battery group are connected to the PFC boost circuit, so that the first battery group can be discharged through the PFC boost circuit, thereby promoting the balance between the first battery group and the second battery group.

[0183] When the first battery pack is the positive electrode BAT of the double battery pack + the corresponding battery pack, the structure of the uninterruptible power supply can be seen in Figure 2 , that is, only the positive electrode BAT+ of the dual battery pack is connected to the input end of the PFC boost circuit.

[0184] When the first battery pack is the battery pack corresponding to the negative electrode BAT- of the double battery pack, the structure of the uninterruptible power supply can be seen in Figure 3 , that is, only the negative electrode BAT- of the dual battery pack is connected to the input end of the PFC boost circuit.

[0185] For the specific structure, working mode, specific control method, and working process under each working mode of the PFC boost circuit, battery bidirectional circuit, balanced bridge circuit and conversion circuit in the second uninterruptible power supply provided in this embodiment, reference can be made to the description in the various embodiments of the above-mentioned first uninterruptible power supply, and no further details will be given here.

[0186] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0187] 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.

[0188] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0189] 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 for a dual battery pack, characterized in that: The battery pack of the uninterruptible power supply is a dual battery pack, and the dual battery pack includes two battery packs connected in series; the uninterruptible power supply includes: A PFC boost circuit, whose input end is used to connect to the mains input, and whose input end is also used to connect to the positive electrode of the dual battery pack through a first switch, and to connect to the negative electrode of the dual battery pack through a second switch; 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 and the second port corresponding to the battery side are respectively used to connect the positive electrode and the negative electrode of the dual battery pack, the third port and the fourth port corresponding to the bus side are respectively used to connect the two polarity ends of the DC bus, and the fifth port is used to connect the neutral line and the neutral line of the dual battery pack; A balancing bridge circuit, connected to the DC bus, for balancing the voltage difference between the positive capacitor and the negative capacitor; In the battery power supply mode, the dual battery pack charges the positive capacitor and the negative capacitor through a battery bidirectional circuit, and when the capacity difference between the two battery packs in the dual battery pack is greater than a preset difference, the battery pack with higher capacity in the dual battery pack charges the positive capacitor or the negative capacitor through a PFC boost circuit.

2. An uninterruptible power supply for a dual battery pack according to claim 1, characterized in that: In the battery power supply mode, when the battery group with higher capacity in the dual battery group is the first battery group corresponding to the positive electrode of the dual battery group, the first switch is turned on; when the battery group with higher capacity in the dual battery group is the second battery group corresponding to the negative electrode of the dual battery group, the second switch is turned on.

3. An uninterruptible power supply for a dual battery pack according to claim 2, characterized in that: The uninterruptible power supply also includes a controller, a third switch and a fourth switch; The input end of the PFC boost circuit is connected to the mains input through the third switch, and the battery bidirectional circuit is connected to the dual battery pack through the fourth switch; The controller is used to: When the AC power input from the mains fails, the third switch is controlled to be disconnected and the fourth switch is turned on to enter the battery power supply mode; the battery power supply mode is specifically: the electric energy stored in the dual 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 dual battery pack to the DC bus; 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 and provide it to the load; and, determining whether a capacity difference between two battery packs in the dual battery pack is greater than a preset difference, and determining a battery pack with a higher capacity in the dual battery pack; If the capacity difference between the two battery groups in the dual battery group is greater than a preset difference, and the battery group with a higher capacity in the dual battery group is the first battery group, controlling the first switch to be turned on and the second switch to be turned off; If the capacity difference between the two battery groups in the dual battery group is greater than a preset difference, and the battery group with a higher capacity in the dual battery group is the second battery group, the first switch is controlled to be disconnected, and the second switch is controlled to be turned on.

4. An uninterruptible power supply for a dual battery pack according to claim 3, characterized in that: The controller is also used for: When the AC power input from the mains is normal, controlling the first switch to be disconnected, the second switch to be disconnected, the third switch to be turned on, and the fourth switch to be turned on, to enter the mains power supply mode; When the AC power input from the mains fails, the third switch is controlled to be disconnected and the fourth switch is turned on, thereby entering a battery power supply mode; The battery power supply mode further includes: if the capacity difference between the two battery packs in the dual battery pack is less than or equal to a preset difference, controlling the first switch to be disconnected, and controlling the second switch to be disconnected.

5. The uninterruptible power supply for dual battery pack according to claim 2, characterized in that: The PFC boost circuit includes a third inductor, a first diode, a second diode, a fifth switch tube and a sixth switch tube; The first end of the third inductor serves as the input end of the PFC boost circuit; the second end of the third inductor is respectively connected to the anode of the first diode, the cathode of the second diode and the collector of the fifth switch tube; The cathode of the first diode is used to connect the positive bus; The anode of the second diode is used to connect the negative bus; The emitter of the fifth switch tube is connected to the emitter of the sixth switch tube, and the collector of the sixth switch tube is used to connect to the neutral line.

6. The uninterruptible power supply for dual battery pack according to claim 2, characterized in that: The mains input is three-phase alternating current, the uninterruptible power supply comprises three first switches, three second switches, three third switches and three PFC boost circuits, each phase of the three-phase alternating current corresponds to a first switch, a second switch, a third switch and a PFC boost circuit; For each phase, the first end of the corresponding third switch is used to connect the AC power of the phase, and the second end of the corresponding third switch is connected to the input end of the PFC boost circuit of the phase; The input end of the corresponding PFC boost circuit is also connected to the second end of the first switch of the phase and the second end of the second switch of the phase, and the output end of the corresponding PFC boost circuit is connected to the DC bus.

7. An uninterruptible power supply for a dual battery pack according to claim 2, characterized in that: The third switch includes a first thyristor and a second thyristor, the first switch includes the third thyristor, and the second switch includes a fourth thyristor; The PFC boost circuit includes a third inductor, a fourth inductor, a first diode, a second diode, a fifth switch tube and a sixth 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 third switch; the cathode of the first thyristor serves as the first port of the second end of the third switch and is connected to the first end of the third inductor; the anode of the second thyristor serves as the second port of the second end of the third switch and is connected to the first end of the fourth inductor; The second end of the third inductor is connected to the anode of the first diode and the collector of the fifth switch tube respectively; the cathode of the first diode is connected to the positive bus; the emitter of the fifth switch tube is used to connect to the neutral line; The second end of the fourth inductor is connected to the emitter of the sixth 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 sixth switch tube is used to connect to the neutral line; The anode of the third thyristor serves as the first end of the first switch; the cathode of the third thyristor serves as the second end of the first switch and is connected to the first end of the third inductor; The cathode of the fourth thyristor serves as the first end of the second switch; the anode of the fourth thyristor serves as the second end of the second switch and is connected to the first end of the fourth inductor.

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

9. An uninterruptible power supply for a dual battery pack according to any one of claims 1 to 8, characterized in that: The battery bidirectional circuit includes a first inductor, a second inductor, a first switch tube, a second switch tube, a third switch tube and a fourth switch tube; The first end of the first inductor serves as the first port of the battery bidirectional circuit, and is used to connect to the positive electrode of the dual battery pack; The second end of the first inductor is respectively connected to the emitter of the first switch tube and the collector of the second switch tube; The collector of the first switch tube serves as the third port of the battery bidirectional circuit, and is used to connect the positive bus; The emitter of the second switch tube is connected to the collector of the third switch tube, and the emitter of the second switch tube serves as the fifth port of the battery bidirectional circuit, and is used to connect the neutral line of the dual battery group and the neutral line; The first end of the second inductor serves as the second port of the battery bidirectional circuit, and is used to connect to the negative electrode of the dual battery pack; The second end of the second inductor is respectively connected to the emitter of the third switch tube and the collector of the fourth switch tube; The emitter of the fourth switch tube serves as the fourth port of the battery bidirectional circuit and is used to connect to the negative bus.

10. An uninterruptible power supply for a dual battery pack, characterized in that: The battery pack of the uninterruptible power supply is a dual battery pack, the dual battery pack includes a first battery pack and a second battery pack connected in series, the capacity of the first battery pack is greater than the capacity of the second battery pack; the uninterruptible power supply includes: A PFC boost circuit, whose input end is used to connect the mains input and the target polarity end of the dual battery group; wherein the target polarity end is the polarity end of the dual battery group corresponding to the first battery group; 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 and the second port corresponding to the battery side are respectively used to connect the positive electrode and the negative electrode of the dual battery pack, the third port and the fourth port corresponding to the bus side are respectively used to connect the two polarity ends of the DC bus, and the fifth port is used to connect the neutral line and the neutral line of the dual battery pack; A balancing bridge circuit, connected to the DC bus, for balancing the voltage difference between the positive capacitor and the negative capacitor; In the battery power supply mode, the dual battery pack charges the positive capacitor and the negative capacitor through a battery bidirectional circuit, and when the capacity difference between the two battery packs in the dual battery pack is greater than a preset difference, the first battery pack charges the positive capacitor or the negative capacitor through a PFC boost circuit.

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