No power outage device

Abstract

To provide an uninterruptible power source device which can continue supplying power longer.SOLUTION: A control substrate 71 determines whether a voltage V2 and a voltage V1 detected by a voltage sensor substrate 51 are in synchronization with each other when an abnormality of an inverter power supply is detected. The control substrate 71 controls a switch S3 in an off-state and controls a switch S4 in an on-state when the voltage V2 and the voltage V1 are determined to be synchronization with each other. The control substrate 71 controls the switch S3 in an off-state and controls the switch S4 in an on-state when a predetermined condition is satisfied even if the voltage V2 and the voltage V1 are determined not to be synchronization with each other.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to uninterruptible power supplies. [Background technology]

[0002] Japanese Patent No. 5917921 (Patent Document 1) discloses an uninterruptible power supply device that can switch between an inverter power supply mode, in which AC power supplied from an AC power source is converted by a converter into DC power, and then further converted by an inverter into AC power and supplied to a load, and a bypass power supply mode, in which AC power is supplied directly to a load. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5917921 Summary of the Invention [Problem to be solved by the invention]

[0004] In such an uninterruptible power supply, if an abnormality in inverter power supply is detected, the uninterruptible power supply may be configured to switch from inverter power supply to bypass power supply when the voltage of AC power supplied from the AC power supply used during inverter power supply and the voltage of AC power supplied from the AC power supply used during bypass power supply (bypass input power supply) are synchronized.

[0005] However, due to the influence of noise from the grounding system, the voltage of the AC power supplied from the bypass input power supply may be erroneously detected, and the synchronization determination may not be performed correctly. In such cases, even though the two voltages are actually synchronized, the power supply may not be switched to the bypass power supply, resulting in an interruption of the power supply and a decrease in the continuity of the power supply from the uninterruptible power supply.

[0006] Therefore, a primary object of the present disclosure is to provide an uninterruptible power supply capable of improving the continuity of power supply. [Means for solving the problem]

[0007] The uninterruptible power supply of the present disclosure includes a converter, an inverter, a bypass circuit, a first switch, a second switch, a voltage detection circuit, and a controller. The converter converts AC power supplied from an AC power source into DC power. The inverter converts DC power supplied from the converter or a power storage device into AC power and supplies the AC power to a load. The bypass circuit supplies AC power supplied from a bypass input power source to the load. The first switch is connected between the inverter and the load. The second switch is connected between the bypass input power source and the load. The voltage detection circuit detects the voltage of the AC power supplied from the AC power source as a first voltage and the voltage of the AC power supplied from the bypass input power source as a second voltage. The controller controls the first switch and the second switch to be on or off. When the first switch is controlled to be on, inverter power supply is performed, in which AC power generated by the inverter is supplied to the load. When the second switch is controlled to be on, bypass power supply is performed, in which power from the bypass input power source is supplied to the load. When the controller detects an abnormality in the inverter power supply, it determines whether the first voltage and the second voltage detected by the voltage detection circuit are synchronized. When the controller determines that the first voltage and the second voltage are synchronized, it controls the first switch to be off and the second switch to be on. When a predetermined condition is met, the controller controls the first switch to be off and the second switch to be on, even if it determines that the first voltage and the second voltage are not synchronized. [Effects of the Invention]

[0008] According to the present disclosure, the continuity of power supply can be improved. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a circuit block diagram showing the configuration of a conventional uninterruptible power supply device. [Figure 2] 10 is a flowchart illustrating a procedure for processing when an abnormality occurs in inverter power supply. [Figure 3] 10 is a flowchart illustrating a procedure for controlling a switch. [Figure 4] 1 is a circuit block diagram showing a configuration of an uninterruptible power supply device according to a first embodiment. [Figure 5] 4 is a flowchart illustrating a procedure for processing when an abnormality occurs in inverter power supply according to the first embodiment. [Figure 6] FIG. 10 is a circuit block diagram showing the configuration of an uninterruptible power supply according to a second embodiment. [Figure 7] 10 is a flowchart illustrating a procedure for controlling a switch according to the second embodiment. [Figure 8] FIG. 10 is a circuit block diagram showing the configuration of an uninterruptible power supply according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the following, the same or corresponding parts in the drawings will be denoted by the same reference numerals, and their description will not be repeated in principle.

[0011] [Conventional uninterruptible power supply] First, an example of a conventional uninterruptible power supply will be described. Fig. 1 is a circuit block diagram showing the configuration of a conventional uninterruptible power supply 100.

[0012] The uninterruptible power supply 100 first converts three-phase AC power supplied from a commercial AC power supply 30 into DC power, and then converts the DC power back into three-phase AC power to supply to a load 31. To simplify the drawing and explanation, Fig. 1 shows only a circuit portion corresponding to one phase (for example, the U phase) of the three phases (U phase, V phase, and W phase). The commercial AC power supply 30 corresponds to one embodiment of an "AC power supply."

[0013] The uninterruptible power supply 100 includes an AC input terminal T11, a battery terminal T12, an AC output terminal T13, and a bypass input terminal T14. The AC input terminal T11 receives AC power at a commercial frequency from a commercial AC power supply 30. The bypass input terminal T14 receives AC power at a commercial frequency from a bypass AC power supply 33. The bypass AC power supply 33 may be a commercial AC power supply or a generator. The bypass AC power supply 33 corresponds to one embodiment of a "bypass input power supply."

[0014] The battery terminal T12 is connected to a battery 32. The battery 32 stores DC power. The battery 32 corresponds to one embodiment of a "power storage device." A capacitor may be connected instead of the battery 32. The AC output terminal T13 is connected to a load 31. The load 31 is driven by AC power.

[0015] The uninterruptible power supply 100 further includes a converter 4, a bidirectional chopper 7, an inverter 8, a semiconductor switch 20, switches S1, S3, and S4, electromagnetic coils C3 and C4, an LCD 41, a display board 42, a voltage sensor board 51, a control board 70, and an in-panel relay board 91. The voltage sensor board 51 corresponds to an embodiment of a "voltage detection circuit." The configuration in which the in-panel relay board 91 is added to the control board 70 corresponds to an embodiment of a "controller."

[0016] A first terminal of the switch S1 is connected to the AC input terminal T11, and a second terminal of the switch S1 is connected to the AC terminal 4a of the converter 4. The switch S1 is turned on when the uninterruptible power supply 100 is in use, and is turned off, for example, when maintenance of the uninterruptible power supply 100 is being performed.

[0017] The instantaneous value of an AC input voltage (also simply referred to as "voltage") V2 appearing at a node N2 between the AC input terminal T11 and the switch S1 is configured to be detected by a voltage sensor board 51. The voltage sensor board 51 is connected to the control board 70 via a signal line. The voltage sensor board 51 may also be configured to detect an AC input current.

[0018] Converter 4 is controlled by control board 70, and during normal operation when AC power is supplied from commercial AC power supply 30, converter 4 converts the AC power into DC power and outputs it to DC line 6. When AC power is no longer being supplied normally from commercial AC power supply 30 (when there is a power outage in commercial AC power supply 30), operation of converter 4 is stopped. The output voltage of converter 4 can be controlled to a desired value.

[0019] Specifically, the converter 4 has a plurality of switching elements (not shown). A gate driver (not shown) is connected to the plurality of switching elements. The gate driver is connected to the control board 70 via a communication line and drives the plurality of switching elements in accordance with gate signals provided from the control board 70.

[0020] The DC line 6 is connected to a high-voltage side node of a bidirectional chopper 7, and the low-voltage side node of the bidirectional chopper 7 is connected to a battery terminal T12 via a switch S2.

[0021] The switch S2 is turned on when the uninterruptible power supply 100 is in use, and is turned off, for example, during maintenance of the uninterruptible power supply 100 and the battery 32. The instantaneous value of the voltage V3 appearing at a node N3 between the battery terminal T12 and the bidirectional chopper 7 is configured to be detected by the voltage sensor board 51.

[0022] The bidirectional chopper 7 is controlled by a control board 70, and normally stores the DC power generated by the converter 4 in the battery 32, and when the commercial AC power supply 30 fails, supplies the DC power from the battery 32 to the inverter 8 via the DC line 6.

[0023] When storing DC power in the battery 32, the bidirectional chopper 7 steps down the DC voltage of the DC line 6 and supplies it to the battery 32. When supplying DC power from the battery 32 to the inverter 8, the bidirectional chopper 7 steps up the voltage V3 of the battery 32 and outputs it to the DC line 6. The DC line 6 is connected to the input node of the inverter 8.

[0024] Specifically, the bidirectional chopper 7 has a plurality of switching elements (not shown). A gate driver (not shown) is connected to the plurality of switching elements. The gate driver is connected to the control board 70 via a communication line and drives the plurality of switching elements in accordance with gate signals provided from the control board 70.

[0025] The inverter 8 is controlled by the control board 70, and converts DC power supplied from the converter 4 or the bidirectional chopper 7 via the DC line 6 into AC power of a commercial frequency and outputs the converted power. That is, the inverter 8 normally converts DC power supplied from the converter 4 via the DC line 6 into AC power, and converts DC power supplied from the battery 32 via the bidirectional chopper 7 into AC power in the event of a power outage in the commercial AC power supply 30. The output voltage of the inverter 8 can be controlled to a desired value.

[0026] Specifically, the inverter 8 has a plurality of switching elements (not shown). A gate driver is connected to the plurality of switching elements. The gate driver is connected to the control board 70 via a communication line and drives the plurality of switching elements in accordance with gate signals provided from the control board 70.

[0027] The switch S3 is connected between the inverter 8 and the load 31. The AC terminal 8a of the inverter 8 is connected to a first terminal of the switch S3, and a second terminal of the switch S3 is connected to the AC output terminal T13. The instantaneous value of a voltage V4 appearing at a node N4 between the switch S3 and the AC output terminal T13 is configured to be detected by a voltage sensor board 51.

[0028] The switch S3 is controlled by a controller (control board 70, in-panel relay board 91). The switch S3 is turned on during inverter power feeding, in which AC power generated by the inverter 8 is supplied to the load 31, and is turned off during bypass power feeding, in which AC power from the bypass AC power supply 33 is supplied to the load 31. The switch S3 corresponds to one example of a "first switch."

[0029] The semiconductor switch 20 includes a pair of thyristors connected in anti-parallel to each other and is connected between the bypass input terminal T14 and a node N5. The node N5 is located between the second terminal of the switch S3 and the AC output terminal T13. The node N4 is located between the node N5 and the AC output terminal T13.

[0030] The switch S4 is connected between the bypass AC power supply 33 and the load 31. Specifically, the switch S4 is connected in parallel with the semiconductor switch 20. The switch S4 corresponds to one embodiment of the "second switch." The semiconductor switch 20 is controlled by the control board 70. The semiconductor switch 20 is normally controlled to be off, and is controlled to be on when an abnormality occurs in the inverter power supply, such as a failure of the inverter 8, and supplies AC power from the bypass AC power supply 33 to the load 31 (bypass power supply).

[0031] In this embodiment, the bypass circuit 21 includes a semiconductor switch 20, a switch S4, and an electromagnetic coil C4. The bypass circuit 21 enables AC power supplied from a bypass AC power supply 33 to be supplied to the load 31.

[0032] The instantaneous value of the voltage V1 appearing at the node N1 between the bypass input terminal T14 and the semiconductor switch 20 is configured to be detected by the voltage sensor board 51.

[0033] The switch S4 is controlled by a controller (the control board 70, the in-panel relay board 91). The switch S4 is controlled to be OFF during inverter power supply and ON during bypass power supply. The switch S4 is controlled to be ON when an abnormality in the inverter power supply occurs, such as a failure of the inverter 8, and supplies AC power from the bypass AC power supply 33 to the load 31.

[0034] Contactor 52C includes a switch S3 and an electromagnetic coil C3. Contactor 52S includes a switch S4 and an electromagnetic coil C4. Switch S3 of contactor 52C and switch S4 of contactor 52S are controlled by the operation of an in-panel relay board 91 based on commands from control board 70. Specifically, in-panel relay board 91 controls switches S3 and S4 to turn on or off in accordance with an on command or off command given from control board 70.

[0035] The control board 70 controls the entire uninterruptible power supply 100 based on information from the voltage sensor board 51, and information from gate drivers respectively connected to the converter 4, bidirectional chopper 7, and inverter 8. The control board 70 detects whether a power outage has occurred based on the detected value of the AC input voltage V2, and controls the converter 4 and inverter 8 in synchronization with the phase of the AC input voltage V2.

[0036] The control board 70 normally controls the converter 4 so that the DC voltage becomes a desired target voltage, and stops the operation of the converter 4 when the commercial AC power supply 30 experiences a power outage.

[0037] Furthermore, the control board 70 controls the bidirectional chopper 7 based on the DC voltage and the battery voltage V3. Under normal circumstances, the control board 70 controls the bidirectional chopper 7 so that the battery voltage V3 becomes a desired target battery voltage, and in the event of a power outage in the commercial AC power supply 30, controls the bidirectional chopper 7 so that the DC voltage becomes the desired target voltage. Furthermore, the control board 70 controls the inverter 8 so that the AC output voltage V4 becomes the desired target voltage.

[0038] The control board 70 includes at least an AD converter 84, a control FPGA (Field Programmable Gate Array) 81, a DSP (Digital Signal Processor) 82, and a sequence FPGA 83.

[0039] The AD converter 84 converts the input analog information into digital information and outputs it. Specifically, the AD converter 84 acquires voltages V1 to V4 as analog information from the voltage sensor board 51. The AD converter 84 converts the acquired voltages V1 to V4 into digital values ​​and transmits them to the control FPGA 81. The AD converter 84 may also acquire analog information such as a current value, convert it into digital information, and transmit it to the control FPGA 81. The voltage V2 corresponds to an example of a "first voltage." The voltage V1 corresponds to an example of a "second voltage."

[0040] The control FPGA 81 controls the inverter 8, the converter 4, and the bidirectional chopper 7 via the gate driver based on the acquired information on the voltages V1 to V4, and also controls the switches S3, S4, etc. via the in-panel relay board 92.

[0041] The DSP 82 performs synchronization detection (detection of data for synchronization determination) and synchronization determination, which will be described later, based on voltage information acquired from the voltage sensor board 51, and issues commands to control the switches S3 and S4. The sequence FPGA 83 controls the in-panel relay board 92 based on commands from the DSP 82.

[0042] The control board 70 is not limited to the above configuration, but may include a processor, memory, and input / output interface (IF). The processor, memory, and input / output IF can exchange signals with each other via a bus (not shown). The processor is composed of at least one integrated circuit. The integrated circuit may be composed of, for example, at least one central processing unit (CPU), at least one micro processing unit (MPU), at least one FPGA, or a combination thereof.

[0043] The memory includes a ROM (Read Only Memory) and a RAM (Random Access Memory). The memory may also include an SD card, etc. The processor reads programs from the ROM to the RAM and executes the various programs to control the operation of the uninterruptible power supply 100. The RAM functions as a working memory and temporarily stores various data required for executing the programs. The input / output IF is an interface for exchanging data with the gate driver, the voltage sensor board 51, etc.

[0044] The in-panel relay board 91 includes terminals T21 to T24, electromagnetic coils C5 and C6, and switches S5 and S6. The in-panel relay board 91 controls a contactor including switch S5 and electromagnetic coil C5 and a contactor including switch S6 and electromagnetic coil C6. The control board 71 is connected to electromagnetic coil C5 via terminal T21. The control board 71 is connected to electromagnetic coil C6 via terminal T22. Switch S5 is connected to electromagnetic coil C3 via terminal T23. Switch S6 is connected to electromagnetic coil C4 via terminal T24.

[0045] The control board 70 transmits ON / OFF commands to the switches S3 and S4. This is achieved by the sequence FPGA 83 transmitting control commands for the switches S3 and S4 to the in-board relay board 91 based on the control commands from the DSP 82 or the synchronization determination results.

[0046] Specifically, when inverter power supply is performed, the sequence FPGA 83 transmits an ON command for the switch S3 (contactor 52C) to the in-panel relay board 91. When the sequence FPGA 83 transmits an OFF command for the switch S3 (contactor 52C) to the in-panel relay board 91, inverter power supply is stopped.

[0047] The in-panel relay board 91 controls the electromagnetic coil C5 to a conductive state based on an ON command to the switch S3 (contactor 52C) and maintains this conductive state, while controlling the electromagnetic coil C5 to a non-conductive state based on an OFF command to the switch S3 and maintains this non-conductive state.

[0048] The switch S5 is configured to be turned on when the electromagnetic coil C5 is energized and turned off when the electromagnetic coil C5 is de-energized. The electromagnetic coil C3 of the contactor 52C is configured to be turned on when the switch S5 is on and turned off when the switch S5 is off. When the electromagnetic coil C3 is energized, the switch S3 is turned on, and when the electromagnetic coil C3 is de-energized, the switch S3 is turned off.

[0049] That is, when an ON command is sent to switch S3 (contactor 52C), the electromagnetic coil C5 is energized, turning switch S5 ON, which in turn energizes electromagnetic coil C3, turning switch S3 ON and enabling inverter power supply. When an OFF command is sent to switch S3, inverter power supply is stopped.

[0050] Furthermore, when bypass power feeding is performed, the sequence FPGA 83 transmits an ON command for the switch S4 (contactor 52S) to the in-panel relay board 91. When the sequence FPGA 83 transmits an OFF command for the switch S4 (contactor 52S) to the in-panel relay board 91, the bypass power feeding is stopped.

[0051] The in-panel relay board 91 energizes the electromagnetic coil C6 based on an ON command to the switch S4 (contactor 52S) and maintains this energized state, while it deenergizes the electromagnetic coil C6 based on an OFF command to the switch S4 and maintains this deenergized state.

[0052] The switch S6 is configured to be turned on when the electromagnetic coil C6 is energized and turned off when the electromagnetic coil C6 is de-energized. The electromagnetic coil C4 of the contactor 52S is configured to be energized when the switch S6 is on and turned off when the switch S6 is off. When the electromagnetic coil C4 is energized, the switch S4 is turned on, and when the electromagnetic coil C4 is de-energized, the switch S4 is turned off.

[0053] That is, when an ON command is sent to switch S4 (contactor 52S), the electromagnetic coil C6 is energized, turning switch S6 ON, which in turn energizes electromagnetic coil C4, turning switch S4 ON and enabling bypass power supply.When an OFF command is sent to switch S4, the bypass power supply is stopped.

[0054] The control board 70 is connected to an LCD (Liquid Crystal Display) 41 via a display board 42. The LCD 41 displays various information related to the uninterruptible power supply 100. The display board 42 controls the display of the LCD 41 based on commands from the control board 70.

[0055] The process flow will be explained below using a flowchart. Figure 2 is a flowchart explaining the procedure for processing when an abnormality occurs in the inverter power supply. For example, this process may be started at a predetermined interval (for example, every 10 msec).

[0056] As described above, the voltage sensor board 51 detects the voltage of the AC power supplied from the commercial AC power supply 30 as voltage V2, and detects the voltage of the AC power supplied from the bypass AC power supply 33 as voltage V1. The voltages V1 and V2 are converted into digital data by the AD converter 84, acquired by the control FPGA 81, and further transmitted to the DSP 82.

[0057] When this process starts, the control board 70 determines in S101 whether or not an abnormality in the inverter power supply has been detected. An "abnormality in the inverter power supply" refers to a situation in which, for example, a failure of the inverter 8 (or a failure of the converter 4 or the bidirectional chopper 7) occurs, making it impossible to supply inverter power.

[0058] If the control board 70 determines that an abnormality in the inverter power supply has been detected (YES in S101), the process proceeds to S102. On the other hand, if the control board 70 does not determine that an abnormality in the inverter power supply has been detected (NO in S101), the process ends.

[0059] In S102, the control board 70 (DSP 82) acquires the voltages V2 and V1 detected by the voltage sensor board 51 (this process is referred to as "synchronous detection"). The voltages V2 and V1 here are digital data converted by the AD converter 84.

[0060] In S103, the control board 70 determines whether the voltages V2 and V1 are synchronized (this process is referred to as "synchronization determination"). In S103, the control board 70 compares the voltage, frequency, and phase of the voltages V2 and V1 to determine whether they are synchronized. In S102, time-series data of the voltages V2 and V1 is acquired for a period long enough to perform synchronization determination.

[0061] If the control board 70 determines that the voltage V2 and the voltage V1 are synchronized (YES in S103), the process proceeds to S104. On the other hand, if the control board 70 does not determine that the voltage V2 and the voltage V1 are synchronized (NO in S103), the process ends.

[0062] In S104, the control board 70 transmits an OFF command to the switch S3. In S105, the control board 70 transmits an ON command to the switch S4.

[0063] In this way, when the control board 71 detects an abnormality in the inverter power supply, it determines whether the voltage V2 and voltage V1 detected by the voltage sensor board 51 are synchronized. If the control board 71 determines that the voltages V2 and V1 are synchronized, it sends an OFF command to switch S3 and an ON command to switch S4. As a result, as described above, the inverter power supply stops and the bypass power supply starts.

[0064] 3 is a flowchart illustrating the procedure for the process of controlling the switches. This process is implemented by the above-mentioned in-panel relay board 91. This process can be implemented by software, hardware, or a combination of these. When this process is implemented by software, it can be started at a predetermined interval (for example, every 10 msec).

[0065] When this process starts, if the in-panel relay board 91 receives an ON command for the switch S3 (YES in S201), it puts the electromagnetic coil C5 into a conductive state and controls the switch S5 to be ON (S202). If the control board 70 receives an OFF command for the switch S3 (YES in S203), it puts the electromagnetic coil C5 into a non-conductive state and controls the switch S5 to be OFF (S204). As a result, when the switch S3 is turned ON based on the ON command for the switch S3, the inverter power supply is performed, and when the OFF command for the switch S3 is received, the inverter power supply is stopped.

[0066] When the control board 70 receives an ON command for the switch S4 (YES in S205), it puts the electromagnetic coil C6 into a conductive state and controls the switch S6 to be ON (S206). When the control board 70 receives an ON command for the switch S4 (YES in S207), it puts the electromagnetic coil C6 into a non-conductive state and controls the switch S6 to be OFF (S208). As a result, when the switch S4 is turned ON based on the ON command for the switch S4, bypass power supply is performed, and when the switch S4 is turned OFF, the bypass power supply is stopped.

[0067] In this way, the controller consisting of the control board 70 and the internal relay board 91 controls the on or off of the switches S3 and S4 based on the on / off commands sent by the control board 70 to the switches S3 and S4 and the operation of the internal relay board 91.

[0068] Furthermore, when uninterruptible power supply 100 detects an abnormality in inverter power supply, if it determines that voltage V2 and voltage V1 are synchronized, it switches from inverter power supply to bypass power supply (this operation is called "protection interlock operation"). In this way, uninterruptible power supply 100 continues to supply power to load 31 by performing either inverter power supply or bypass power supply.

[0069] In the above, voltage V1 may be erroneously detected due to the influence of noise, and voltage V2 may be determined to be out of sync with voltage V1 even though voltage V2 is actually sync with voltage V1. In this case, even if voltage V1 is normal, the system will not switch to bypass power supply. In this case, for example, if inverter power supply is physically stopped due to a failure in inverter 8 or the like, the system will not be able to switch to bypass power supply even though bypass power supply is possible. In this case, power will not be supplied to load 31, which will reduce the continuity of power supply from uninterruptible power supply 100. To prevent such a reduction in power supply continuity, the uninterruptible power supply is configured as described below.

[0070] [Embodiment 1] The following describes the configuration of the uninterruptible power supply 101 according to embodiment 1. Fig. 4 is a circuit block diagram showing the configuration of the uninterruptible power supply 101 according to embodiment 1. Below, the configuration that differs from the conventional uninterruptible power supply 100 described using Figs. 1 to 3 will be described, and descriptions of parts that are the same as those of the uninterruptible power supply 100 will be omitted.

[0071] The difference between the conventional uninterruptible power supply 100 shown in FIG. 1 and the uninterruptible power supply 101 shown in FIG. 4 is that the functions of bypass voltage detection and synchronization determination are duplicated.

[0072] Specifically, the uninterruptible power supply 100 shown in FIG. 1 includes a voltage sensor board 51 and an AD converter 84, and the DSP 82 determines synchronization based on the voltages V1 and V2 acquired from the voltage sensor board 51.

[0073] In contrast to this, the uninterruptible power supply 101 shown in Fig. 4 is provided with two voltage sensor boards 51 and 52 and two AD converters 84 and 85, and performs double synchronization determination in the DSP 82. This will be explained in detail below.

[0074] As shown in Fig. 4, uninterruptible power supply 101 includes voltage sensor boards 51 and 52. Control board 71 includes AD converters 84 and 85. Voltage sensor board 52 corresponds to one embodiment of a "second voltage detection circuit." The configuration in which control board 71 is added with in-panel relay board 91 corresponds to one embodiment of a "controller."

[0075] As in the uninterruptible power supply 100, the voltage sensor board 51 acquires voltages V1 to V4. The AD converter 84 converts the voltages V1 to V4 into digital information and transmits it to the control FPGA 81. The DSP 82 acquires the voltages V1 and V2 from the control FPGA 81 (synchronization detection) and performs synchronization determination based on the voltages V1 and V2. The above processing is essentially the same as the processing in the uninterruptible power supply 100.

[0076] In the uninterruptible power supply 101, the signal line of the voltage V1 input to the voltage sensor board 51 is branched so that the voltage V1 is also input to the voltage sensor board 52. This makes it possible for the voltage sensor board 52 to acquire the voltage V1 as well.

[0077] Furthermore, the AD converter 85 acquires the voltage V1 from the voltage sensor board 52. Here, the voltage V1 acquired from the voltage sensor board 51 is referred to as "voltage V1," while the voltage V1 acquired from the voltage sensor board 52 is referred to as "voltage V1a." The voltage V1a corresponds to an example of a "third voltage."

[0078] The AD converter 85 converts the voltage V1a into digital information and transmits it to the control FPGA 81. The DSP 82 acquires the voltages V1a and V2 from the control FPGA 81 (synchronization detection) and performs synchronization determination based on the voltages V1a and V2. Note that the voltage sensor board 52 may be configured to be able to acquire the voltages V1 and V2, and synchronization determination may be performed using the voltages V1 and V2 acquired from the voltage sensor board 52.

[0079] A controller made up of the control board 71 and the in-panel relay board 91 controls the switches S3 and S4 to be on or off based on the on / off commands sent from the control board 71 to the switches S3 and S4 and the operation of the in-panel relay board 91. The following explains this process using a flowchart.

[0080] Fig. 5 is a flowchart illustrating the procedure for processing when an abnormality occurs in the inverter power supply according to the first embodiment. The flowchart in Fig. 5 differs from the flowchart in Fig. 2 in that the functions of detecting the bypass voltage and determining synchronization are duplicated. When an abnormality occurs in the inverter power supply, the control board 71 is configured to further determine whether or not the voltage V2 and the voltage V1a are synchronized.

[0081] As described above, the voltage sensor board 51 detects the voltage of the AC power supplied from the commercial AC power supply 30 as voltage V2, and detects the voltage of the AC power supplied from the bypass AC power supply 33 as voltage V1. Furthermore, the voltage sensor board 52 detects the voltage of the AC power supplied from the bypass AC power supply 33 as voltage V1a. The voltages V1 and V2 are converted into digital data by AD converter 84, and the voltage V1a is converted into digital data by AD converter 85, and the converted digital data is then acquired by the control FPGA 81 and further transmitted to the DSP 82.

[0082] When this process starts, the control board 71 determines in S301 whether or not an abnormality in the inverter power supply has been detected. If the control board 71 determines that an abnormality in the inverter power supply has been detected (YES in S301), the process proceeds to S302. On the other hand, if the control board 71 does not determine that an abnormality in the inverter power supply has been detected (NO in S301), the process ends.

[0083] In S302, the control board 71 acquires the voltages V2 and V1 detected by the voltage sensor board 51 (synchronous detection). In S303, the control board 71 acquires the voltage V1a detected by the voltage sensor board 52 (synchronous detection).

[0084] In S304, the control board 71 determines whether or not the voltage V2 and the voltage V1 are synchronized (synchronization determination). Here, the synchronization determination is performed using the voltage V1 detected by the voltage sensor board 51.

[0085] If the control board 71 determines that the voltage V2 and the voltage V1 are synchronized (YES in S304), the process proceeds to S306. On the other hand, if the control board 71 does not determine that the voltage V2 and the voltage V1 are synchronized (NO in S304), the process proceeds to S305.

[0086] In S305, the control board 71 determines whether or not the voltage V2 and the voltage V1a are synchronized (synchronization determination). Here, the synchronization determination is performed using the voltage V1a detected by the voltage sensor board 52.

[0087] If the control board 71 determines that the voltage V2 and the voltage V1a are synchronized (YES in S305), the process proceeds to S306. On the other hand, if the control board 71 does not determine that the voltage V2 and the voltage V1a are synchronized (NO in S305), the process ends.

[0088] In S306, the control board 71 sends an OFF command to the switch S3. In S309, the control board 71 sends an ON command to the switch S4, and ends this process.

[0089] In other words, when compared with voltage V2, if either the voltage V1 detected by voltage sensor board 51 or the voltage V1a detected by voltage sensor board 52 is synchronized, inverter power supply is stopped and bypass power supply is started.

[0090] The procedure for controlling the switch according to the first embodiment is the same as the procedure shown in the flowchart of FIG.

[0091] 1, for example, noise may flow into the voltage sensor board 51 or the AD converter 84 of the control board 71 from the grounding system of the power supply that supplies power to the control board 71, etc. The effect of this noise may cause the voltage V1 in the memory of the control board 71 to be momentarily replaced with an incorrect value.

[0092] As a countermeasure against the above, the uninterruptible power supply 101 has dual functions for detecting the bypass voltage and determining synchronization. This allows correct synchronization determination based on the voltages V2 and V1a even if the voltage sensor board 51 or the AD converter 84 is affected by noise and does not correctly detect the voltage V1, resulting in an inability to determine that the voltages V2 and V1 are synchronized. On the other hand, even if the voltage sensor board 52 or the AD converter 85 is affected by noise and does not correctly detect the voltage V1a, resulting in an inability to determine that the voltages V2 and V1a are synchronized, it allows correct synchronization determination based on the voltages V2 and V1.

[0093] In this way, the synchronization determination can be performed while eliminating the influence of noise by using two systems. If the voltage is synchronized in either of the synchronization determinations, the system switches to bypass power supply. If the voltage is not synchronized in either of the synchronization determinations, the system determines that an abnormality has occurred in the bypass system and does not switch to bypass power supply.

[0094] In the conventional uninterruptible power supply 100, the control board 70 does not send an ON command to the switch S4 when it determines that the voltages V2 and V1 are not synchronized. That is, the in-panel relay board 91 does not control the switch S4 to be ON. In contrast, in the uninterruptible power supply 101 according to the first embodiment, the control board 71 sends an ON command to the switch S4 when a predetermined condition is met, even if it determines that the voltages V2 and V1 are not synchronized. That is, the in-panel relay board 91 controls the switch S4 to be ON when it determines that the voltages V2 and V1 are not synchronized. The predetermined condition is met when it determines that the voltages V2 and V1a are synchronized. As a result, bypass power feeding is started when either the voltages V2 and V1 are synchronized or the voltages V2 and V1a are synchronized.

[0095] As described above, by doubling the functions of bypass voltage detection and synchronization determination, it is possible to prevent erroneous synchronization determination due to noise, thereby improving the reliability of the synchronization determination function. Furthermore, by preventing erroneous synchronization determination due to noise, it is possible to improve the continuity of power supply.

[0096] [Embodiment 2] Fig. 6 is a circuit block diagram showing the configuration of an uninterruptible power supply 102 according to embodiment 2. Below, configurations that differ from the conventional uninterruptible power supply 100 described using Figs. 1 to 3 will be described, and descriptions of parts that are the same as those of the uninterruptible power supply 100 will be omitted.

[0097] The difference between the conventional uninterruptible power supply 100 shown in FIG. 1 and the uninterruptible power supply 102 shown in FIG. 6 is that a function for forcibly switching to a bypass power supply is added.

[0098] Specifically, the on-board relay board 90 in the uninterruptible power supply 102 further includes a forced switching circuit 95 in addition to the on-board relay board 91 shown in FIG. 1. The configuration in which the on-board relay board 90 is added to the control board 70 corresponds to an embodiment of a "controller." The forced switching circuit 95 includes switches S7 and S8 and an electromagnetic coil C7. The uninterruptible power supply 102 further includes an EPO switch 61. The EPO switch 61 is connected to the electromagnetic coil C7 via terminal T15. The EPO switch 61 corresponds to an embodiment of a "third switch."

[0099] In the uninterruptible power supply 100, when an on command is sent to switch S3 (contactor 52C), electromagnetic coil C5 is energized, causing switch S5 to be turned on. This causes electromagnetic coil C3 to be energized, causing switch S3 to be turned on, enabling inverter power supply. When an off command is sent to switch S3, inverter power supply is stopped. Furthermore, in the uninterruptible power supply 100, when an on command is sent to switch S4 (contactor 52S), electromagnetic coil C6 is energized, causing switch S6 to be turned on. This causes electromagnetic coil C4 to be energized, causing switch S4 to be turned on, enabling bypass power supply. When an off command is sent to switch S4, bypass power supply is stopped.

[0100] In contrast, in the uninterruptible power supply 102, even if an ON command is not sent to switch S4 (contactor 52S), the forced switching circuit 95 is configured to forcibly control switch S4 to the ON state by sending an ON command to switch S3 (contactor 52C).

[0101] Specifically, a forced switching circuit 95 connects a node N6 on the first terminal side of the switch S6 to a node N7 on the second terminal side of the switch S6. In the forced switching circuit 95, the switch S8 (contact b) is configured to be turned off when the electromagnetic coil C7 is energized and turned on when the electromagnetic coil C7 is de-energized. When the EPO switch 61 is in the on state, the electromagnetic coil C7 is energized, and when the EPO switch 61 is in the off state, the electromagnetic coil C7 is de-energized. In addition, the switch S7 (contact b) is configured as an auxiliary contact that is turned on when the electromagnetic coil C5 is de-energized and turned off when the electromagnetic coil C5 is energized.

[0102] That is, when an OFF command is sent to switch S3 (contactor 52C), electromagnetic coil C5 is de-energized, which turns switch S5 OFF and switch S7 ON. In this case, when EPO switch 61 is OFF (switch S8 is ON), electromagnetic coil C4 is energized, which turns switch S4 ON, enabling bypass power supply. On the other hand, when an ON command is sent to switch S3, bypass power supply is stopped.

[0103] In this way, when an OFF command is sent to switch S3, the forced switching function of the forced switching circuit 95 forcibly switches switch S4 to the ON state, enabling bypass power supply. However, if the EPO switch 61 is ON, the forced switching function of the forced switching circuit 95 is disabled. In other words, to disable the forced switching function (to stop the forcibly switched bypass power supply), simply turn on the EPO switch 61. The EPO switch 61 also allows the user to freely select whether or not to use the forced switching function.

[0104] The controller, which is composed of the control board 70 and the in-panel relay board 90, controls the on or off of the switches S3 and S4 based on the on / off commands sent by the control board 70 to the switches S3 and S4 and the operation of the in-panel relay board 90.

[0105] Fig. 7 is a flowchart illustrating the procedure for controlling a switch according to embodiment 2. The flowchart in Fig. 7 differs from the flowchart in Fig. 3 in that a forced switching function to bypass power supply is added to the in-panel relay board.

[0106] When this process starts, if the on-board relay board 90 receives an on command for switch S3 (YES in S401), it puts the electromagnetic coil C5 into a conductive state, controls switch S5 to on (S402), and controls switch S7 to off (S403).If the on-board relay board 90 receives an off command for switch S3 (YES in S404), it puts the electromagnetic coil C5 into a non-conductive state, controls switch S5 to off (S405), and controls switch S7 to on (S406).

[0107] In the processes of S201 to S204, inverter power supply is started in response to an ON command to switch S3, and inverter power supply is stopped in response to an OFF command to switch S3. Meanwhile, in the processes of S401 to S406, inverter power supply is started and bypass power supply is forcibly stopped in response to an ON command to switch S3, and inverter power supply is stopped and bypass power supply is forcibly started in response to an OFF command to switch S3. The processes of S403 and S405 are implemented by forced switching circuit 95.

[0108] When the on-board relay board 90 receives an on command for switch S4 (YES in S407), it puts the electromagnetic coil C6 into a conductive state and controls the switch S6 to be on (S408). When the on-board relay board 90 receives an on command for switch S4 (YES in S409) with the electromagnetic coil C6 in a non-conductive state, it controls the switch S6 to be off (S410). These processes are the same as the processes in S205 to S208, and bypass power feeding is started in response to an on command for switch S4, and is stopped in response to an off command for switch S4.

[0109] The procedure of processing when an abnormality occurs in the inverter power supply according to the second embodiment is the same as the procedure according to the flowchart shown in FIG.

[0110] The conventional uninterruptible power supply 100 does not control switch S4 to be on when it is determined that voltage V2 and voltage V1 are not synchronized. In contrast, the uninterruptible power supply 102 according to the second embodiment controls switch S4 to be on when a predetermined condition is met, even when it is determined that voltage V2 and voltage V1 are not synchronized.

[0111] The predetermined condition is met when the forced switching circuit 95 detects a command to turn off the switch S3. In this case, the forced switching circuit 95 is configured to turn on the switch S4 when the switch S3 is turned off. This allows bypass power supply to start regardless of whether the voltages V2 and V1 are synchronized.

[0112] In the uninterruptible power supply 102, when the switch S5 is controlled to be turned off, the switch S7 is forcibly controlled to be turned on. As a result, even if a failure occurs in the uninterruptible power supply 102, making inverter power supply impossible and the switch S3 is controlled to be turned off, and an abnormality occurs in the bypass system (for example, a case is assumed in which the voltage V1 is several to 20% lower and it is determined that the voltages V1 and V2 are not synchronized), the electromagnetic coil C4 can be excited to switch to the bypass power supply as long as it is within a voltage driving range that can drive the contactor 52S. In the uninterruptible power supply 101 according to the second embodiment, it is not possible to switch to the bypass power supply if an abnormality occurs in the bypass system. In contrast, in the uninterruptible power supply 102, by forcibly switching to the bypass power supply even if an abnormality occurs in the bypass system, the continuity of the power supply can be further improved.

[0113] [Embodiment 3] Fig. 8 is a circuit block diagram showing the configuration of an uninterruptible power supply 103 according to embodiment 3. The difference between the conventional uninterruptible power supply 100 shown in Fig. 1 and the uninterruptible power supply 103 shown in Fig. 8 is that the functions of detecting the bypass voltage and determining synchronization are duplicated and a function of forced switching to bypass power supply is added.

[0114] The duplicated function in the uninterruptible power supply 103 shown in FIG. 8 is the same as the function of the uninterruptible power supply 101 shown in FIG. 4 (embodiment 1), and the forced switching function is the same as the function of the uninterruptible power supply 102 shown in FIG. 6 (embodiment 2).

[0115] The uninterruptible power supply 103 includes a control board 71 that includes voltage sensor boards 51 and 52 and AD converters 84 and 85. The uninterruptible power supply 103 further includes an in-panel relay board 90 that includes an EPO switch 61 and a forced switching circuit 95. The configuration in which the in-panel relay board 90 is added to the control board 71 corresponds to one embodiment of the "controller."

[0116] The controller, which is composed of the control board 71 and the in-panel relay board 90, controls the on or off of the switches S3 and S4 based on the on / off commands sent by the control board 71 to the switches S3 and S4 and the operation of the in-panel relay board 90.

[0117] The processing procedure when an abnormality occurs in the inverter power supply according to the third embodiment is the same as the processing procedure according to the flowchart shown in Fig. 5. The processing procedure for controlling the switches according to the third embodiment is the same as the processing procedure according to the flowchart shown in Fig. 7.

[0118] In this way, in the uninterruptible power supply 103, even if an abnormality occurs in one synchronization detection function, if the other synchronization detection function detects a normal voltage, the detected value of the normal voltage is used to determine synchronization. This makes it possible to prevent erroneous determination of synchronization due to noise.

[0119] If it is determined that the voltages are not synchronized in either of the two synchronization determinations, it is considered that there is an abnormality in the bypass system itself, rather than a false detection of the bypass voltage. Even if an abnormality occurs in the bypass system, when contactor 52C (switch S3) is controlled to be turned off, if the voltage drive region is such that the contactor can be driven, contactor 52S (switch S4) can be forcibly controlled to be turned on, thereby switching to bypass power supply. In this way, the continuity of power supply can be improved in uninterruptible power supply 103.

[0120] For example, in the second embodiment, a scenario may arise in which voltage V1 is erroneously detected due to noise, and the controller detects some kind of inverter power supply abnormality, after which the inverter power supply is physically stopped. In this case, voltages V2 and V1 are not synchronized at the time the inverter power supply abnormality is detected (NO in S103 of FIG. 2), and therefore the inverter power supply is not switched to bypass power supply (the processes of S104 and S105 are not executed). If the inverter power supply is subsequently physically stopped without detecting a voltage, electromagnetic coil C3 is no longer excited, and switch S3 changes to the OFF state. In this case, the forced switching function is activated by the stop of inverter power supply, and therefore the inverter power supply is switched to bypass power supply even without the duplicated synchronization determination function. However, in this case, there is a slight time lag between the stop of inverter power supply and the start of bypass power supply, and power supply to load 31 is stopped during that time. On the other hand, in the third embodiment, the duplicated synchronization determination function switches to bypass power feeding (S304 to S307) at the timing when an abnormality in the inverter power feeding is detected (S301 in FIG. 5), so that the above-mentioned power feeding stop does not occur (the switching process can be speeded up). Therefore, the third embodiment can improve the continuity of power feeding more than the second embodiment.

[0121] 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]

[0122] 4 Converter, 6 DC line, 7 Bidirectional chopper, 8 Inverter, 20 Semiconductor switch, 21 Bypass circuit, 30 Commercial AC power supply, 31 Load, 32 Battery, 33 Bypass AC power supply, 41 LCD, 42 Display board, 51, 52 Voltage sensor board, 61 EPO switch, 70, 71 Control board, 81 Control FPGA, 82 DSP, 83 Sequence FPGA, 84, 85 AD converter, 91, 92 In-panel relay board, 95 Forced switching circuit, 100-103 Uninterruptible power supply, C4-C8 Electromagnetic coil, S1-S8 Switch, T11 AC input terminal, T12 Battery terminal, T13 AC output terminal, T15, T21-T24 Terminals.

Claims

1. a converter that converts AC power supplied from an AC power source into DC power; an inverter that converts DC power supplied from the converter or the power storage device into AC power and supplies the AC power to a load; a bypass circuit that supplies AC power supplied from a bypass input power source to the load; a first switch connected between the inverter and the load; a second switch connected between the bypass input power supply and the load; a voltage detection circuit that detects a voltage of AC power supplied from the AC power supply as a first voltage and detects a voltage of AC power supplied from the bypass input power supply as a second voltage; a controller that controls the first switch and the second switch to be on or off; When the first switch is controlled to be turned on, inverter power supply is performed to supply AC power generated by the inverter to the load, When the second switch is controlled to be turned on, a bypass power supply is performed to supply power from the bypass input power supply to the load; The controller When an abnormality in the inverter power supply is detected, it is determined whether or not the first voltage and the second voltage detected by the voltage detection circuit are synchronized; when it is determined that the first voltage and the second voltage are synchronized, the first switch is controlled to be turned off and the second switch is controlled to be turned on; an uninterruptible power supply that, when a predetermined condition is met, controls the first switch to be turned off and the second switch to be turned on, even if it is determined that the first voltage and the second voltage are not synchronized.

2. a second voltage detection circuit that detects a voltage of the AC power supplied from the bypass input power supply as a third voltage; When the controller detects an abnormality in the inverter power supply, the controller further determines whether the first voltage and the third voltage are synchronized; 2. The uninterruptible power supply according to claim 1, wherein the predetermined condition is met when it is determined that the first voltage and the third voltage are synchronized.

3. a forced switching circuit configured to control the second switch to be on when the first switch is controlled to be off; 2. The uninterruptible power supply according to claim 1, wherein the predetermined condition is met when the forced switching circuit detects a command to control the first switch to be turned off.

4. a second voltage detection circuit that detects the voltage of the AC power supplied from the bypass input power supply as a third voltage; a forced switching circuit configured to control the second switch to be on when the first switch is controlled to be off; When the controller detects an abnormality in the inverter power supply, the controller further determines whether the first voltage and the third voltage are synchronized; 2. The uninterruptible power supply according to claim 1, wherein the predetermined condition is met when it is determined that the first voltage and the third voltage are synchronized, or when a command to control the first switch to be turned off is detected in the forced switching circuit.

5. 5. The uninterruptible power supply according to claim 3, further comprising a third switch that disables the forced switching circuit.

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