Uninterruptible power supply system, uninterruptible power supply device, and updating method for uninterruptible power supply device

Abstract

To provide an uninterruptible power supply system, an uninterruptible power supply device, and an updating method for the uninterruptible power supply device to avoid power outages to a load during updating the uninterruptible power supply.SOLUTION: In an updating method for an uninterruptible power supply device, a step of preparing to transfer a load from a first uninterruptible power supply (20A) to a second uninterruptible power supply (20B) includes: a step of connecting a switch circuit (51) between a branch terminal (T10) of the first uninterruptible power supply device and a branch terminal (T10) of the second uninterruptible power supply device; a step of switching the first uninterruptible power supply device (20A) to a bypass power supply when a first switch (32) of a distribution panel (31) is turned on and a second switch (33) is turned off; a step of turning a switch (52) of a switch circuit (51) on; and a step of switching the second uninterruptible power supply device (20B) to a bypass power supply. A step of switching the load includes a step of turning the second switch (33) on and a step of turning the first switch (32) off when the second switch (33) is turned on.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to an uninterruptible power supply system, an uninterruptible power supply device, and an update method for an uninterruptible power supply device. [Background technology]

[0002] In an uninterruptible power supply system equipped with one or more uninterruptible power supplies (UPS), in order to ensure the reliability of electrical equipment, work is carried out to update a UPS whose operating time has reached a predetermined time (see, for example, Patent Document 1).

[0003] In this upgrade, the existing UPS is disconnected from the load and the load is transferred to the new UPS. Specifically, the existing UPS is disconnected by switching the circuit breaker installed between the existing UPS and the load from on to off, and the load is transferred to the new UPS by switching the circuit breaker installed between the new UPS and the load from off to on.

[0004] During this upgrade work, both the existing UPS and the new UPS are set to bypass power supply, which supplies AC power from the AC power source to the load via a bypass circuit. When controlling the on / off of the two circuit breakers, an overlap time is set during which both circuit breakers are on, allowing for uninterrupted load transfer. This allows power to continue being supplied to the load even during the upgrade work. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-161989 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in an uninterruptible power supply system, the AC power supply connected to the existing UPS and the AC power supply connected to the new UPS may be different power sources. If the amplitudes and phases of the two AC voltages respectively supplied by bypass from the two different AC power sources are not synchronized, a cross current may flow between the existing UPS and the new UPS during the overlap time of the two circuit breakers.

[0007] Therefore, as a countermeasure against cross current, conventional uninterruptible power supply systems are configured so that when the AC power source connected to the existing UPS and the AC power source connected to the new UPS are different power sources, there is no overlap time when controlling the on / off of the two circuit breakers. That is, after switching the circuit breaker installed between the existing UPS and the load from on to off, the circuit breaker installed between the new UPS and the load is switched from off to on. This prevents the occurrence of cross current. However, there is a problem in that the load cannot be transferred without interruption, and power supply to the load is stopped during the upgrade work.

[0008] The present disclosure has been made to solve these problems, and its main purpose is to provide an uninterruptible power supply system, an uninterruptible power supply, and an uninterruptible power supply updating method that can avoid stopping the power supply to a load when updating the uninterruptible power supply. [Means for solving the problem]

[0009] An uninterruptible power supply system according to one embodiment of the present disclosure includes a first uninterruptible power supply, a second uninterruptible power supply, a distribution board for connecting either the first or second uninterruptible power supply to a load, and a switch circuit.

[0010] The first uninterruptible power supply includes a first AC input terminal receiving AC power from a first AC power source, a first AC output terminal, a first bypass circuit connected between the first AC input terminal and the first AC output terminal, a first power converter, a first switching circuit, and a first bypass input switching circuit. The first power converter is connected between the first AC input terminal and the first AC output terminal and generates AC power based on AC power from the first AC power source or DC power from a first storage battery. The first switching circuit switches between connection and disconnection of the first AC input terminal with the first bypass circuit and the first power converter. The first bypass input switching circuit has a first end connected to the first bypass circuit, a first branch line branching from the first bypass circuit, and a first branch terminal to which a second end of the first branch line is connected.

[0011] The second uninterruptible power supply includes a second AC input terminal receiving AC power from a second AC power source, a second AC output terminal, a second bypass circuit connected between the second AC input terminal and the second AC output terminal, a second power converter, a second switching circuit, and a second bypass input switching circuit. The second power converter is connected between the second AC input terminal and the second AC output terminal and generates AC power based on AC power from the second AC power source or DC power from the second storage battery. The second switching circuit switches between connection and disconnection between the second AC input terminal and the second bypass circuit and the second power converter. The second bypass input switching circuit has a first end connected to the second bypass circuit, a second branch line branching from the second bypass circuit, and a second branch terminal to which a second end of the second branch line is connected.

[0012] The switch circuit includes a first terminal configured to be electrically connectable to the first branch terminal, a second terminal configured to be electrically connectable to the second branch terminal, and a switch connected between the first terminal and the second terminal. The distribution board includes a first switch connected between the first AC output terminal and the load, and a second switch connected between the second AC output terminal and the load.

[0013] An uninterruptible power supply according to one embodiment of the present disclosure includes an AC input terminal that receives AC power from an AC power source, an AC output terminal, a bypass circuit connected between the AC input terminal and the AC output terminal, a power converter connected between the AC input terminal and the AC output terminal and that generates AC power based on AC power from the AC power source or DC power from a storage battery, a switching circuit for connecting the bypass circuit and the power converter to the AC input terminal, and a bypass input switching circuit provided between the switching circuit and the power converter. The bypass input switching circuit has a first end connected to the bypass circuit and includes a branch line branching from the bypass circuit, and a branch terminal to which a second end of the branch line is connected.

[0014] An uninterruptible power supply updating method according to one aspect of the present disclosure is a method for updating uninterruptible power supplies in the uninterruptible power supply system, comprising the steps of preparing to transfer a load from a first uninterruptible power supply to a second uninterruptible power supply and transferring the load from the first uninterruptible power supply to the second uninterruptible power supply. The step of preparing to transfer the load includes the steps of connecting a first terminal and a second terminal of a switch circuit to a first branch terminal and a second branch terminal, respectively, transitioning the first uninterruptible power supply from an inverter power feeding mode in which AC power is supplied to a load from a first AC power supply via a first power converter to a bypass power feeding mode in which AC power is supplied to the load from the first AC power supply via a first bypass circuit while the first switch is on and the second switch is off, turning on a switch of the switch circuit, and setting the second uninterruptible power supply to a bypass power feeding mode in which AC power is supplied to the load via the second bypass circuit. The step of transferring the load includes the steps of turning on the second switch and turning off the first switch while the second switch is in the on state. [Effects of the Invention]

[0015] According to the present disclosure, even when the AC power source connected to an existing uninterruptible power supply and the AC power source connected to a newly installed uninterruptible power supply are separate power sources, the uninterruptible power supply can be updated without stopping the power supply to the load. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a diagram showing a configuration of an uninterruptible power supply system according to an embodiment of the present invention; [Figure 2] 10 is a flowchart showing the procedure of an uninterruptible power supply updating method according to the present embodiment. [Figure 3] FIG. 3 is a diagram illustrating the process of step S10 in FIG. 2. [Figure 4] FIG. 3 is a diagram illustrating the processing of steps S20 to S40 in FIG. [Figure 5] FIG. 3 is a diagram illustrating the process of step S50 in FIG. 2. [Figure 6] FIG. 3 is a diagram illustrating the processing of steps S70 and S80 in FIG. [Figure 7] FIG. 1 is a diagram illustrating a configuration of an uninterruptible power supply system of a comparative example. [Figure 8] FIG. 10 is a diagram illustrating a method for updating an uninterruptible power supply device in an uninterruptible power supply system of a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals, and description thereof will not be repeated.

[0018] [Comparative Example] First, an uninterruptible power supply system of a comparative example will be described.

[0019] Fig. 7 is a diagram showing the configuration of an uninterruptible power supply system of a comparative example. As shown in Fig. 1, an uninterruptible power supply system 1000 of the comparative example includes a first uninterruptible power supply 200A, a second uninterruptible power supply 200B, a distribution board 31, and storage batteries B1 and B2.

[0020] The first uninterruptible power supply 200A is connected to the first AC power supply 1 via a transformer 6. A circuit breaker 11 is provided between the transformer 6 and the first uninterruptible power supply 200A, and disconnects the first uninterruptible power supply 200A from the first AC power supply 1 in the event of an accident or the like in the first AC power supply 1.

[0021] The second uninterruptible power supply 200B is connected to the second AC power supply 7 via a transformer 8. A circuit breaker 12 is provided between the transformer 8 and the second uninterruptible power supply 200B, and disconnects the second uninterruptible power supply 200B from the second AC power supply 7 in the event of an accident or the like in the second AC power supply 7.

[0022] The first uninterruptible power supply 200A receives a first AC voltage from a first AC power supply 1 via a transformer 6. The second uninterruptible power supply 200B receives a second AC voltage from a second AC power supply 7 via a transformer 8. In this specification, the first AC power supply 1 and the second AC power supply 7 are referred to as different power supplies when the first AC power supply 1 and the second AC power supply 7 are different, or when the first AC power supply 1 and the second AC power supply 7 are the same but the transformers 6 and 8 are different. When the first AC power supply 1 and the second AC power supply 7 are different power supplies, the phase and amplitude of the first AC voltage may not be synchronized with the phase and amplitude of the second AC voltage.

[0023] The first uninterruptible power supply 200A includes a first input / output panel 21A and a first UPS (Uninterruptible Power Supply) U1. The second uninterruptible power supply 200B includes a second input / output panel 21B and a second UPS U2. The first uninterruptible power supply 200A and the second uninterruptible power supply 200B have the same configuration. Therefore, the following description will be given representatively of the first uninterruptible power supply 200A.

[0024] The first input / output board 21A includes an AC input terminal T5, an AC output terminal T9, output terminals T6 and T7, an input terminal T8, and switches 13 to 17. The AC input terminal T5 receives a first AC voltage from a first AC power source 1. The first AC voltage is three-phase or single-phase. The AC output terminal T9 is connected to an AC input terminal T11 of a distribution board 31.

[0025] The switch 13 is connected between the AC input terminal T5 and the output terminal T6. The switch 14 is connected between the AC input terminal T5 and the output terminal T7. The switches 13 and 14 are turned on when the first UPSU 1 is operating and turned off, for example, during maintenance of the first UPSU 1. The switches 13 and 14 correspond to an example of a "switching circuit" for switching between connection and disconnection of the AC input terminal T5 to the bypass circuit 4 and each of the power converters (converter 2 and inverter 3).

[0026] The switch 15 is connected in series between the AC input terminal T5 and the AC output terminal T9. The switch 15 is turned off when the first UPSU 1 is operating, and turned on, for example, during maintenance of the first UPSU 1. The switch 17 is always turned on, and turned off during maintenance of the first uninterruptible power supply 200A.

[0027] The switch 16 is connected between the input terminal T8 and the connection point of the switches 15 and 17. The switch 16 is turned on when the first UPSU 1 is operating, and turned off when the first UPSU 1 is undergoing maintenance, for example.

[0028] The first UPSU 1 includes an AC input terminal T1, a bypass input terminal T2, a battery terminal T3, an AC output terminal T4, a converter 2, an inverter 3, and a bypass circuit 4.

[0029] The AC input terminal T1 is connected to the output terminal T7 of the first input / output panel 21 A. The bypass input terminal T2 is connected to the output terminal T6 of the first input / output panel 21 A. When the first UPSU 1 is operating, the AC input terminal T1 receives the first AC voltage from the first AC power supply 1 via the switch 14, and the bypass input terminal T2 receives the first AC voltage from the first AC power supply 1 via the switch 13.

[0030] Battery terminal T3 is connected to storage battery B1. AC output terminal T4 is connected to input terminal T8 of first input / output panel 21A. When first UPSU 1 is operating, AC output terminal T4 is connected to AC output terminal T9 via switches 16 and 17.

[0031] Converter 2 and inverter 3 are connected in series between AC input terminal T1 and AC output terminal T4. Converter 2 converts AC power input from first AC power source 1 via AC input terminal T1 into DC power. The DC power generated by converter 2 is provided to storage battery B1 via battery terminal T3 and to inverter 3. Storage battery B1 stores the DC power from converter 2. Inverter 3 converts the DC power from converter 2 or storage battery B1 into AC power. The AC power generated by inverter 3 is provided to distribution board 31 via AC output terminal T4, switches 16 and 17, and AC output terminal T9. Converter 2 and inverter 3 correspond to an embodiment of a "power converter."

[0032] The bypass circuit 4 is connected between the bypass input terminal T2 and the AC output terminal T4. In this specification, the "bypass circuit 4" is defined to include the connection line connecting the bypass input terminal T2 to the output terminal T6 of the first input / output board 21A.

[0033] The bypass circuit 4 has a bypass switching circuit 5. The bypass switching circuit 5 is configured to include a switch (not shown). The switch is turned off in an inverter power supply mode in which AC power generated by the inverter 3 is supplied to the loads 61 and 62, and is turned on in a bypass power supply mode in which AC power is supplied from the first AC power source 1 to the loads 61 and 62 via the bypass circuit 4. In other words, the bypass switching circuit 5 is configured to be able to switch between the output of the inverter 3 and the output of the bypass circuit 4.

[0034] The first uninterruptible power supply 200A operates in inverter power supply mode. If a failure occurs in the converter 2 or the inverter 3 during inverter power supply mode, the first uninterruptible power supply 200A shifts from the inverter power supply mode to the bypass power supply mode. Furthermore, during an uninterruptible power supply update operation, which will be described later, the first uninterruptible power supply 20A shifts from the inverter power supply mode to the bypass power supply mode.

[0035] The distribution board 31 is provided between the AC output terminals T9 of the uninterruptible power supplies 200A, 200B and the loads 61, 62. The distribution board 31 includes AC input terminals T11, T12, AC output terminals T13, T14, and switches 32, 33.

[0036] The AC input terminal T11 is connected to the AC output terminal T9 of the first input / output board 21A. The AC input terminal T12 is connected to the AC output terminal T9 of the second input / output board 21B. The AC output terminal T13 is connected to a load 61. The AC output terminal T14 is connected to a load 62. The first switch 32 is connected between the AC input terminal T11 and the AC output terminals T13 and T14. The second switch 33 is connected between the AC input terminal T12 and the AC output terminals T13 and T14.

[0037] The first switch 32 is turned on when AC power from the first uninterruptible power supply 200A is supplied to the loads 61, 62, and is turned off when AC power from the second uninterruptible power supply 200B is supplied to the loads 61, 62. The second switch 33 is turned on when AC power from the second uninterruptible power supply 200B is supplied to the loads 61, 62, and is turned off when AC power from the first uninterruptible power supply 200A is supplied to the loads 61, 62. In other words, the distribution board 31 is configured to be able to switch between the output of the first uninterruptible power supply 200A and the output of the second uninterruptible power supply 200B.

[0038] Next, a method for updating the uninterruptible power supply device in the uninterruptible power supply system 1000 of the comparative example will be described.

[0039] In the following explanation, it is assumed that the first uninterruptible power supply 200A is an "existing uninterruptible power supply" currently in use, and the second uninterruptible power supply 200B is a "new uninterruptible power supply" that will be newly used. A method of updating the first uninterruptible power supply 200A (existing uninterruptible power supply) to the second uninterruptible power supply 200B (new uninterruptible power supply) will be explained using Fig. 8.

[0040] The first uninterruptible power supply device 200A normally operates in the inverter power supply mode. In the distribution board 31, the first switch 32 is turned on and the second switch 33 is turned off.

[0041] In the update work of the first uninterruptible power supply 200A, the first uninterruptible power supply 200A is disconnected from the loads 61 and 62, and the loads 61 and 62 are transferred to the second uninterruptible power supply 20B. This transfer of the loads 61 and 62 can be performed by controlling the on / off of switches 32 and 33 of the distribution board 31.

[0042] Specifically, first, the first uninterruptible power supply device 200A is switched from the inverter power supply mode to the bypass power supply mode, whereby a power path P11 is formed between the first AC power supply 1 and the loads 61 and 62, passing through the bypass circuit 4 of the first uninterruptible power supply device 200A and the first switch 32 of the distribution board 31.

[0043] Furthermore, the second uninterruptible power supply 200B starts operating in the bypass power supply mode, whereby a power path P12 is formed between the second AC power supply 7 and the AC input terminal T12 of the distribution board 31, passing through the bypass circuit 4 of the second uninterruptible power supply 200B.

[0044] Next, the first switch 32 of the distribution board 31 is turned off and the second switch 33 is turned on. As a result, the loads 61 and 62 are transferred to the second uninterruptible power supply 200B, and the second uninterruptible power supply 200B starts supplying power to the loads 61 and 62. In response to the start of power supply by the second uninterruptible power supply 200B, the operation of the first uninterruptible power supply 200A is stopped.

[0045] Finally, the second uninterruptible power supply apparatus 200B is switched from the bypass power supply mode to the inverter power supply mode.

[0046] In the update method described above, when controlling the on / off of the first switch 32 and the second switch 33 of the distribution board 31, by providing an overlap time during which the switches 32 and 33 are both on, the loads 61 and 62 can be transferred without interruption.

[0047] Here, the first uninterruptible power supply 200A and the second uninterruptible power supply 200B need to be from the same power supply in order to provide an overlap time for the switches 32 and 33. This is because, if the first uninterruptible power supply 200A and the second uninterruptible power supply 200B are from different power supplies, the amplitude and phase of the AC voltage output from the AC output terminal T9 of the first uninterruptible power supply 200A will differ from the amplitude and phase of the AC voltage output from the AC output terminal T9 of the second uninterruptible power supply 200B, which could result in a cross current being generated between the first uninterruptible power supply 200A and the second uninterruptible power supply 200B.

[0048] However, when the first UPSU 1 and the second UPSU 2 are each operating in the inverter power supply mode, even if the first uninterruptible power supply 200A and the second uninterruptible power supply 200B are the same power supply, the amplitude and phase of the AC voltage output from the first uninterruptible power supply 200A may differ from the amplitude and phase of the AC voltage output from the AC output terminal T9 of the second uninterruptible power supply 200B. Therefore, when updating the first uninterruptible power supply 200A, both the first uninterruptible power supply 200A and the second uninterruptible power supply 200B are set to the bypass power supply mode.

[0049] 8, in the bypass power supply mode, AC power is substantially supplied from the first AC power supply 1 to the loads 61 and 62, and AC power is supplied from the second AC power supply 7 to the loads 61 and 62. Therefore, if the first AC power supply 1 and the second AC power supply 7 are the same power supply, an overlap time can be provided in the on / off control of the switches 32 and 33. As a result, the loads 61 and 62 can be switched without any interruption.

[0050] However, in the uninterruptible power supply system 1000 of the comparative example, the first AC power supply 1 and the second AC power supply 7 are different power supplies, so it is not possible to provide an overlap time for the on / off control of the switches 32 and 33. Therefore, it is not possible to transfer the loads 61 and 62 without interruption, and the power supply to the loads 61 and 62 is stopped during the update work.

[0051] In order to address such problems, the uninterruptible power supply system according to this embodiment has the configuration described below, and updates the uninterruptible power supply device without stopping the power supply to the loads 61 and 62.

[0052] [Embodiment Mode] (Uninterruptible Power Supply System) Fig. 1 is a diagram showing the configuration of an uninterruptible power supply system according to the present embodiment. As shown in Fig. 1, an uninterruptible power supply system 100 according to the present embodiment includes a first uninterruptible power supply device 20A, a second uninterruptible power supply device 20B, a distribution board 31, and storage batteries B1 and B2.

[0053] The uninterruptible power supply system 100 according to the present embodiment differs from the uninterruptible power supply system 1000 according to the comparative example shown in FIG. 7 in that the uninterruptible power supplies 200A and 200B are replaced with uninterruptible power supplies 20A and 20B, respectively.

[0054] The first uninterruptible power supply 20A is connected to the first AC power supply 1 via a circuit breaker 11 and a transformer 6. The first uninterruptible power supply 20A includes a first input / output panel 21A, a first UPSU 1, and a first bypass input switching circuit 41A. The first uninterruptible power supply 20A differs from the first uninterruptible power supply 200A in that the first uninterruptible power supply 20A includes a first bypass input switching circuit 41A.

[0055] The first bypass input switching circuit 41A is disposed between the output terminal T6 of the first input / output board 21A and the bypass input terminal T2 of the first UPSU 1. The first bypass input switching circuit 41A includes a branch line 410 and a branch terminal T10.

[0056] The branch line 410 has a first end connected to the bypass circuit 4 (more specifically, a connection line connecting the output terminal T6 to the bypass input terminal T2) and branches off from the bypass circuit 4. A second end of the branch line 410 is connected to the branch terminal T10. The first bypass input switching circuit 41A is a circuit for switching the AC power supply connected to the bypass input terminal T2 of the first UPSU 1 between the first AC power supply 1 and an AC power supply other than the first AC power supply 1.

[0057] The second uninterruptible power supply 20B is connected to the second AC power supply 7 via a circuit breaker 12 and a transformer 8. The second uninterruptible power supply 20B includes a second input / output panel 21B, a second UPSU 2, and a second bypass input switching circuit 41B. The second uninterruptible power supply 20B differs from the second uninterruptible power supply 200B in that the second uninterruptible power supply 20B includes a second bypass input switching circuit 41B.

[0058] The second bypass input switching circuit 41B is disposed between the output terminal T6 of the second input / output board 21B and the bypass input terminal T2 of the second UPSU 2. The second bypass input switching circuit 41B has a configuration similar to that of the first bypass input switching circuit 41A, and includes a branch line 410 and a branch terminal T10.

[0059] The branch line 410 has a first end connected to the bypass circuit 4 (more specifically, a connection line connecting the output terminal T6 to the bypass input terminal T2) and branches off from the bypass circuit 4. A second end of the branch line 410 is connected to the branch terminal T10. The second bypass input switching circuit 41B is a circuit for switching the AC power supply connected to the bypass input terminal T2 of the second UPSU 2 between the second AC power supply 7 and an AC power supply other than the second AC power supply 7.

[0060] (How to update an uninterruptible power supply) Next, a method for updating an uninterruptible power supply device in uninterruptible power supply system 100 according to the present embodiment will be described.

[0061] In the following explanation, it is assumed that the first uninterruptible power supply 20A is an "existing uninterruptible power supply" currently in use, and the second uninterruptible power supply 20B is a "new uninterruptible power supply" that will be newly used. A method for updating the first uninterruptible power supply 20A (existing uninterruptible power supply) to the second uninterruptible power supply 20B (new uninterruptible power supply) will be explained using Figures 2 to 6.

[0062] Fig. 2 is a flowchart showing the steps of the uninterruptible power supply updating method according to the present embodiment. Steps S10 to S40 in Fig. 2 correspond to steps of preparing to transfer loads 61 and 62 from first uninterruptible power supply 20A to second uninterruptible power supply 20B. Steps S50 to S80 in Fig. 2 correspond to steps of transferring loads 61 and 62.

[0063] Fig. 3 is a diagram illustrating the processing of step S10 in Fig. 2. As shown in Fig. 3, the first uninterruptible power supply 20A normally operates in the inverter power supply mode. In the distribution board 31, the first switch 32 is turned on and the second switch 33 is turned off. As a result, a power path P1 is formed between the first AC power supply 1 and the loads 61 and 62, passing through the converter 2 and inverter 3 of the first uninterruptible power supply 20A and the first switch 32 of the distribution board 31.

[0064] When updating the first uninterruptible power supply 20A, first in step S10, the switch circuit 51 is connected to the uninterruptible power supply system 100. As shown in FIG. 3, the switch circuit 51 includes a first terminal T21, a second terminal T22, and a switch 52.

[0065] The first terminal T21 is connected to the branch terminal T10 of the first bypass input switching circuit 41A via a cable 53. The second terminal T22 is connected to the branch terminal T10 of the second bypass input switching circuit 41B via a cable 54. The switch 52 is connected between the first terminal T21 and the second terminal T22.

[0066] Next, in step S20, the first uninterruptible power supply device 20A shifts from the inverter power supply mode to the bypass power supply mode. In S20, the switch included in the bypass switching circuit 5 of the first UPSU 1 is switched from off to on.

[0067] Next, in step S30, switch 13 included in second input / output panel 21B is turned off. Turning switch 13 off disconnects second AC power supply 7 from bypass circuit 4 of second uninterruptible power supply 20B. Next, switch 52 of switch circuit 51 is turned on. Turning switch 52 on electrically connects bypass circuit 4 of first uninterruptible power supply 20A to bypass circuit 4 of second uninterruptible power supply 20B via branch line 410 of first bypass input switching circuit 41A, cable 53, switch 52, cable 54, and branch line 410 of second bypass input switching circuit 41B.

[0068] Fig. 4 is a diagram illustrating the processing of steps S20 to S40 in Fig. 2. As shown in Fig. 4, when the first uninterruptible power supply 20A shifts from the inverter power supply mode to the bypass power supply mode, a power path P2 is formed between the first AC power supply 1 and the loads 61, 62, passing through the bypass circuit 4 of the first uninterruptible power supply 20A and the first switch 32 of the distribution board 31. Note that, because the switch 13 of the second input / output board 21B is turned off, the second AC power supply 7 and the bypass circuit 4 of the second uninterruptible power supply 20B are disconnected.

[0069] Next, in step S40, the second uninterruptible power supply 20B is set to the bypass power supply mode. In S40, the switch included in the bypass switching circuit 5 of the second UPSU 2 is turned on.

[0070] As a result, a power path P3 is formed between the first AC power supply 1 and input terminal T12 of the distribution board 31, passing through the bypass circuit 4 of the first uninterruptible power supply 20A, the branch line 410 of the first bypass input switching circuit 41A, the cable 53, the switch 52, the cable 54, the branch line 410 of the second bypass input switching circuit 41B, and the bypass circuit 4 of the second uninterruptible power supply 20B. Because the bypass circuit 4 of the first uninterruptible power supply 20A and the bypass circuit 4 of the second uninterruptible power supply 20B both receive power from the first AC power supply 1, the bypass circuit 4 of the first uninterruptible power supply 20A and the bypass circuit 4 of the second uninterruptible power supply 20B are from the same power source.

[0071] Next, S50 and S60 perform on / off control of the switches 32 and 33 of the distribution board 31. Because the bypass circuit 4 of the first uninterruptible power supply 20A and the bypass circuit 4 of the second uninterruptible power supply 20B are powered by the same power source, an overlap time during which the switches 32 and 33 are both on can be provided in the on / off control of the switches 32 and 33.

[0072] In the on / off control, first, the second switch 33 is turned on in S50. FIG. 5 is a diagram illustrating the processing of step S50 in FIG. 2. As shown in FIG. 5, when both switches 32 and 33 are turned on, power is supplied to the loads 61 and 62 from both the power path P2 and the power path P3. Next, in S60, the first switch 32 is turned off. As a result, the power path P2 is disconnected from the loads 61 and 62, and the power supply to the loads 61 and 62 is switched to the power path P3 without any interruption.

[0073] Next, in step S70, the second uninterruptible power supply 20B shifts from the bypass power supply mode to the inverter power supply mode. Figure 6 is a diagram illustrating the processing of steps S70 and S80 in Figure 2. In S70, while power is being supplied via the power path P3 shown in Figure 5, the second UPSU 2 is switched to the inverter power supply mode, thereby forming a power path P4 between the second AC power supply 7 and the loads 61, 62, which passes through the converter 2 and the inverter 3 of the second uninterruptible power supply 20B and the second switch 33 of the distribution board 31.

[0074] Next, in step S80, switch 52 of switch circuit 51 is turned off. Then, switch 13 of second input / output panel 21B is turned on. This causes loads 61 and 62 to be switched to power supply from power path P4, that is, normal inverter power supply from second uninterruptible power supply 20B with second AC power supply 7 as the bypass input of bypass circuit 4.

[0075] As described above, in uninterruptible power supply system 100 according to the present embodiment, existing uninterruptible power supply (first uninterruptible power supply 20A) and new uninterruptible power supply (second uninterruptible power supply 20B) are each provided with bypass input switching circuits 41A and 41B for switching the AC power source connected to bypass circuit 4 between multiple AC power sources 1 and 7. Therefore, when updating the uninterruptible power supplies, the existing uninterruptible power supply and the new uninterruptible power supply can be made to share the same power source by connecting bypass input switching circuit 41A and bypass input switching circuit 41B via switch circuit 51. This allows an overlap time to be provided in the on / off control of switches 32 and 33 of distribution board 31, making it possible to avoid interruption of power supply to loads 61 and 62 during work to update the uninterruptible power supplies.

[0076] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0077] 1,7 AC power supply, 2 converter, 3 inverter, 4 bypass circuit, 5 bypass switching circuit, 6,8 transformer, 11,12 circuit breaker, 13-17,32,33,52 switch, 20A,200A first uninterruptible power supply, 20B,200B second uninterruptible power supply, 21A,21B input / output panel, 31 distribution panel, 51 switch circuit, 61,62 load, 100,1000 uninterruptible power supply system, 410 branch line, U1,U2 UPS, B1,B2 storage battery, T1,T5,T11,T12 AC input terminal, T2 bypass input terminal, T3 battery terminal, T4,T9,T13,T14 AC output terminal, T6,T7 output terminal, T8 input terminal, T10 branch terminal, T21 first terminal, T22 Second terminal.

Claims

1. 1. An uninterruptible power supply system, comprising: a first uninterruptible power supply; a second uninterruptible power supply; a distribution board for connecting one of the first and second uninterruptible power supplies to a load; a switch circuit, The first uninterruptible power supply a first AC input terminal for receiving AC power from a first AC power supply; a first AC output terminal; a first bypass circuit connected between the first AC input terminal and the first AC output terminal; a first power converter connected between the first AC input terminal and the first AC output terminal, and configured to generate AC power based on AC power from the first AC power supply or DC power from a first storage battery; a first switching circuit for switching between connection and disconnection between the first AC input terminal and each of the first bypass circuit and the first power converter; a first bypass input switching circuit, the first bypass input switching circuit having a first end connected to the first bypass circuit, a first branch line branching from the first bypass circuit, and a first branch terminal to which a second end of the first branch line is connected; The second uninterruptible power supply a second AC input terminal for receiving AC power from a second AC power supply; a second AC output terminal; a second bypass circuit connected between the second AC input terminal and the second AC output terminal; a second power converter connected between the second AC input terminal and the second AC output terminal, and configured to generate AC power based on AC power from the second AC power supply or DC power from a second storage battery; a second switching circuit for switching between connection and disconnection between the second AC input terminal, the second bypass circuit, and the second power converter; a second bypass input switching circuit, the second bypass input switching circuit having a first end connected to the second bypass circuit, a second branch line branching from the second bypass circuit, and a second branch terminal to which a second end of the second branch line is connected; The switch circuit a first terminal configured to be electrically connectable to the first branch terminal; a second terminal configured to be electrically connectable to the second branch terminal; a switch connected between the first terminal and the second terminal; The distribution board is a first switch connected between the first AC output terminal and the load; a second switch connected between the second AC output terminal and the load.

2. an AC input terminal for receiving AC power from an AC power source; an AC output terminal; a bypass circuit connected between the AC input terminal and the AC output terminal; a power converter connected between the AC input terminal and the AC output terminal, and generating AC power based on AC power from the AC power supply or DC power from a storage battery; a switching circuit for connecting the bypass circuit and the power converter to the AC input terminal; a bypass input switching circuit provided between the switching circuit and the power converter, The bypass input switching circuit comprises: a branch line having a first end connected to the bypass circuit and branching off from the bypass circuit; and a branch terminal to which the second end of the branch line is connected.

3. 2. A method for updating an uninterruptible power supply device in an uninterruptible power supply system according to claim 1, comprising: preparing to transfer the load from the first uninterruptible power supply to the second uninterruptible power supply; transferring the load from the first uninterruptible power supply to the second uninterruptible power supply; The step of preparing the load transfer includes: connecting the first terminal and the second terminal of the switch circuit to the first branch terminal and the second branch terminal, respectively; a step of transitioning the first uninterruptible power supply from inverter power feeding, in which AC power is supplied to the load from the first AC power supply via the first power converter, to bypass power feeding, in which AC power is supplied to the load from the first AC power supply via the first bypass circuit, while the first switch is on and the second switch is off; turning on the switch of the switch circuit; and configuring the second uninterruptible power supply as a bypass power supply that supplies AC power to the load via the second bypass circuit, The step of transferring the load includes: turning on the second switch; and turning off the first switch while the second switch is in an on state.

4. The step of transferring the load includes: transitioning the second uninterruptible power supply from a bypass power supply in which AC power is supplied to the load from the first AC power supply via the first bypass input switching circuit, the switch circuit, the second bypass input switching circuit, and the second bypass circuit to an inverter power supply in which AC power is supplied to the load from the second AC power supply via the second power converter; turning off the switch of the switch circuit; 4. The method for updating an uninterruptible power supply according to claim 3, further comprising the step of connecting said second AC power supply and said second bypass circuit by said second switching circuit.

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