Uninterruptible power supply device

Abstract

An uninterruptible power supply device has a plurality of power conversion modules (P) and a bypass module (B0) connected in parallel between an AC power source (30) and a load (31). Each power conversion module (P) includes a first terminal (T1) that receives AC power from the AC power source (30), a second terminal (T2) connected to a power storage device (32), a third terminal (T3) that outputs AC power to the load (31), a converter, an inverter, and a first control circuit (14). The bypass module (B0) includes a switch (20) connected between the AC power source (30) and the load (31), a first voltage detector (22) that detects an AC voltage applied to the first terminal (T1), a second voltage detector (24) that detects a DC voltage applied to the second terminal (T2), a third voltage detector (26) that detects an AC voltage applied to the third terminal (T3), and a second control circuit (28). The second control circuit (28) is communicatively connected to the first control circuit (14) and transmits detection results of the first to third voltage detectors (22, 24, 26) to the first control circuit (14). The first control circuit (14) controls the converter and the inverter using the detection results of the first to third voltage detectors (22, 24, 26) transmitted from the second control circuit (28).

Description

Technical Field

[0001] This disclosure relates to uninterruptible power supply devices. Background Technology

[0002] In a high-capacity uninterruptible power supply (UPS) system, redundancy is achieved by connecting multiple UPS devices in parallel, so that even if one UPS device fails or is under maintenance, the remaining UPS devices can continue to supply power to the load (for example, see Japanese Patent Application Publication No. 2020-195174 (Patent Document 1)).

[0003] On the other hand, small- to medium-capacity uninterruptible power supply (UPS) systems are often composed of a single UPS unit. Therefore, a modular UPS structure with redundancy achieved at the module level is proposed for this single UPS unit. The modular UPS unit connects multiple power conversion modules (hereinafter also referred to as "power modules") in parallel, and has a parallel circuit for the power modules within the device. When N power modules are required for power supply by the UPS unit, redundancy is achieved by installing (N+1) power modules, thereby improving power quality.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2020-195174 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] The aforementioned modular uninterruptible power supply (UPS) device employs a hot-swappable design. Hot-swappable design refers to the ability to stop, remove, and insert the power module during UPS operation. This allows the power module to be replaced while the UPS continues to supply power in the event of a power module failure or maintenance.

[0009] To enable hot-swapping, each power module is equipped with multiple detectors to control the built-in power converter and to monitor the input and output voltages and currents of the power converter. Therefore, the number of detectors increases proportionally to the number of power modules, raising concerns about the increased size and cost of the uninterruptible power supply (UPS).

[0010] Furthermore, since the operation of the power converter is controlled based on the detection values ​​of the detectors for each power module, there is a concern that operational deviations may occur between multiple power modules due to detector errors or other reasons. In this case, a phenomenon of power inflow between multiple power modules (i.e., cross current) may occur.

[0011] The present invention was made to solve the aforementioned problems, and its purpose is to achieve miniaturization and cost reduction in a modular uninterruptible power supply device having multiple power modules connected in parallel, and to suppress operational deviations between the multiple power modules.

[0012] Methods used to solve problems

[0013] An uninterruptible power supply (UPS) device according to a technical solution of the present invention includes: a plurality of power conversion modules connected in parallel between an AC power source and a load; and a bypass module connected between the AC power source and the load. The plurality of power conversion modules are connected in parallel with respect to a power storage device. Each power conversion module includes: a first terminal for receiving AC power from the AC power source; a second terminal connected to the power storage device; a third terminal for outputting AC power to the load; a converter for converting the AC power received at the first terminal into DC power; an inverter for converting the DC power from the converter or the power storage device into AC power and supplying it to the load; and a first control circuit for controlling the converter and the inverter. The bypass module includes: a first switch connected between the AC power source and the load; a first voltage detector for detecting the AC voltage applied to the first terminal; a second voltage detector for detecting the DC voltage applied to the second terminal; a third voltage detector for detecting the AC voltage applied to the third terminal; and a second control circuit for controlling the opening and closing of the first switch. The second control circuit is communicatively connected to the first control circuit and sends the detection results of the first to third voltage detectors to the first control circuit. The first control circuit uses the detection results of the first to third voltage detectors sent from the second control circuit to control the converter and inverter.

[0014] Invention Effects

[0015] According to the present invention, in a modular uninterruptible power supply device having multiple power modules connected in parallel, miniaturization and cost reduction can be achieved, and operational deviations between multiple power modules can be suppressed. Attached Figure Description

[0016] Figure 1 This is a circuit block diagram illustrating the structure of an uninterruptible power supply device according to an embodiment.

[0017] Figure 1 It means Figure 1 The circuit block diagram shown illustrates the structure of the bypass module and the power module.

[0018] Figure 3 It is a diagram that roughly represents the functional structure of the control circuit of the bypass module and the power module.

[0019] Figure 4 yes Figure 3 The diagram shows the functional block diagram of the control unit. Detailed Implementation

[0020] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Furthermore, the same or corresponding parts in the drawings will be assigned the same reference numerals, and their descriptions will generally not be repeated.

[0021] Figure 1 This is a circuit block diagram illustrating the structure of an uninterruptible power supply device according to an embodiment.

[0022] Reference Figure 1 The uninterruptible power supply device 100 of this embodiment includes a bypass module B0, multiple power modules P1 to Pn (n being an integer of 2 or more), a battery 32, and a communication line 15. The bypass module B0 and the power modules P1 to Pn are interconnected by the communication line 15.

[0023] The bypass module B0 has an input terminal T11, a battery terminal T12, an output terminal T13, and a switch (not shown) connected between the input terminal T11 and the output terminal T13.

[0024] Power modules P1 through Pn are power conversion modules containing both a converter and an inverter. In the following description, power modules P1 through Pn are sometimes collectively referred to as "power module P". Power module P has an input terminal T1, a battery terminal T2, and an output terminal T3. Input terminal T1 corresponds to "terminal 1", battery terminal T2 corresponds to "terminal 2", and output terminal T3 corresponds to "terminal 3".

[0025] The input terminal T11 of the bypass module B0 and the input terminals T1 of each power module P are connected to the commercial AC power supply 30. The input terminals T11 and each input terminal T1 receive a commercial frequency AC voltage VI supplied from the commercial AC power supply 30.

[0026] The battery terminal T12 of the bypass module B0 and the battery terminal T2 of each power module P are connected to the battery 32. The battery 32 stores DC power. The battery 32 corresponds to one embodiment of a "power storage device". A capacitor may also be connected instead of the battery 32.

[0027] The output terminal T13 of the bypass module B0 and the output terminal T3 of each power module P are connected to the load 31. That is, the bypass module B0 and the power modules P1 to Pn are connected in parallel between the commercial AC power supply 30 and the load 31. The load 31 is driven by AC power supplied from the bypass module B0 or ​​the power modules P.

[0028] Such uninterruptible power supply (UPS) devices are called "modular UPS devices." Modular UPS devices internally consist of parallel circuits with a number of power modules corresponding to the capacity of the UPS device. When N power modules are required for power supply by the UPS device, redundancy is achieved by installing (N+1) power modules, improving power quality. This method of achieving redundancy at the module level within a single UPS device is also called "hot-swappable." Hot-swappable refers to a structure that allows power modules to be stopped, removed, and inserted during UPS operation. Therefore, in the event of a power module failure or maintenance, the power module P can be replaced while continuing to supply power from the UPS device.

[0029] The uninterruptible power supply (UPS) device 100 has an inverter power supply mode and a bypass power supply mode. In inverter power supply mode, AC power is supplied from the power module P to the load 31. In this mode, the converter in the power module P converts the AC power supplied from the commercial AC power source 30 into DC power, and the inverter converts the DC power back into AC power and supplies it to the load 31. In bypass power supply mode, AC power is supplied from the commercial AC power source 30 to the load 31 via the bypass module B0. In this mode, the AC power supplied from the commercial AC power source 30 is supplied to the load 31 without passing through the power module P.

[0030] Figure 2 It means Figure 1 The circuit block diagram shown illustrates the structure of the bypass module B0 and the power module P. The uninterruptible power supply (UPS) 100 converts three-phase AC power from a commercial AC power source 30 into DC power, then converts the DC power back into three-phase AC power and supplies it to the load 31. Figure 2 For the sake of simplicity in the accompanying drawings and descriptions, only the circuit portion corresponding to one of the three phases (U phase, V phase, W phase) is shown.

[0031] like Figure 2 As shown, the bypass module B0 includes a switch 20, voltage detectors 22, 24, and 26, and a control circuit 28. Switch 20 is connected between input terminal T11 and output terminal T13. Switch 20 is, for example, a thyristor switch with a pair of thyristors connected in reverse parallel. Switch 20 is controlled by the control circuit 28. Switch 20 is open in inverter power supply mode and open in bypass power supply mode. Control circuit 28 corresponds to one embodiment of the "second control circuit".

[0032] Voltage detector 22 detects the instantaneous value of AC voltage (AC voltage applied to input terminal T11) VI at the commercial frequency supplied from commercial AC power supply 30, and sends a signal representing its detected value to control circuit 28.

[0033] Voltage detector 24 detects the inter-terminal voltage (hereinafter also referred to as "battery voltage") VB of battery 32 applied to battery terminal T12 and sends a signal representing its detected value to control circuit 28.

[0034] Voltage detector 26 detects the instantaneous value of AC voltage VO applied to output terminal T13 and sends a signal representing its detected value to control circuit 28.

[0035] Control circuit 28 receives signals representing the detected values ​​of AC voltage VI, battery voltage VB, and AC voltage VO from voltage detectors 22, 24, and 26, respectively. Control circuit 28 is interconnected with control circuit 14 included in power modules P1-Pn via communication line 15. Control circuit 28 exchanges information with control circuit 14 in power modules P1-Pn via communication line 15. Furthermore, communication between control circuit 28 and control circuit 14 can be implemented using either wireless or wired communication. Control circuit 28 transmits signals representing the detected values ​​of AC voltage VI, battery voltage VB, and AC voltage VO to control circuit 14 included in power modules P1-Pn via communication line 15.

[0036] The control circuit 28 may be configured as, for example, a microcomputer. As an example, the control circuit 28 may incorporate a memory (not shown) and a CPU (Central Processing Unit), and the control actions described later can be executed by the CPU executing software processing of a program pre-stored in the memory. Alternatively, some or all of the control actions may be implemented using hardware processing, such as built-in dedicated electronic circuits, instead of software processing.

[0037] In addition to the input terminal T1, battery terminal T2 and output terminal T3, the power module P also has switches S1 to S3, capacitors 1, 5 and 10, reactors 2 and 9, DC line 6, converter 4, bidirectional chopper 7, inverter 8, current detectors 12 and 13 and control circuit 14.

[0038] Input terminal T1 receives commercial frequency AC voltage VI from commercial AC power supply 30. Terminal 1 of switch S1 is connected to input terminal T1, and terminal 2 is connected to the input node of converter 4 via reactor 2. Capacitor 1 is connected to terminal 2 of switch S1. Switch S1 is turned on when the corresponding power module P is in use, and turned off, for example, during maintenance of power module P.

[0039] Capacitor 1 and reactor 2 constitute AC filter 3. AC filter 3 is a low-pass filter that allows the commercial frequency AC current to flow from the commercial AC power supply 30 to the converter 4, preventing the switching frequency signal generated by the converter 4 from flowing to the commercial AC power supply 30 side.

[0040] Current detector 12 detects the current I1 flowing from commercial AC power supply 30 into power module P via input terminal T1, and sends a signal φI1 representing its detected value to control circuit 14. Current detector 12 corresponds to an embodiment of "first current detector". Control circuit 14 corresponds to an embodiment of "first control circuit".

[0041] The converter 4 is controlled by the control circuit 14. When AC power is normally supplied from the commercial AC power source 30 (when the commercial AC power source 30 is intact), it converts the AC power supplied from the commercial AC power source 30 into DC power and outputs it to the DC line 6. When the supply of AC power from the commercial AC power source 30 stops (when the commercial AC power source 30 is de-energized), the operation of the converter 4 is stopped.

[0042] DC line 6 is connected to converter 4, bidirectional chopper 7, and inverter 8. The DC voltage VD presented in DC line 6 is detected by control circuit 14. When the commercial AC power supply 30 is intact, control circuit 14 controls converter 4 so that the DC voltage VD output from converter 4 becomes the reference DC voltage VDr.

[0043] Capacitor 5 is connected to DC line 6 to smooth and stabilize the DC voltage VD of DC line 6. A resistor is connected in parallel with capacitor 5. The resistor reduces the DC voltage VD in the event of a power module P failure, thus protecting the user of the uninterruptible power supply 100. The resistance value of the resistor is set so that the voltage VD between the terminals of capacitor 5 drops to 0V for a short time when the converter 4 is stopped.

[0044] The high-voltage side node of the bidirectional chopper 7 is connected to the DC line 6, and its low-voltage side node is connected to the battery terminal T2 via switch S2. The bidirectional chopper 7 is controlled by control circuit 14. When the commercial AC power supply 30 is intact, the bidirectional chopper 7 stores the DC power generated by the converter 4 into the battery 32. When the commercial AC power supply 30 is interrupted, the bidirectional chopper 7 supplies the DC power from the battery 32 to the inverter 8. Switch S2 is turned on when the power module P is in use, and turned off, for example, when the battery 32 is under maintenance.

[0045] Control circuit 14 receives a signal representing the detected value of battery voltage VB from control circuit 28 via communication line 15. When the commercial AC power supply 30 is intact, control circuit 14 controls bidirectional chopper 7 to make battery voltage VB a reference battery voltage VBr. When the commercial AC power supply 30 is de-energized, control circuit 14 controls bidirectional chopper 7 to make DC voltage VD of DC line 6 a reference DC voltage VDr.

[0046] Inverter 8, controlled by control circuit 14, converts the DC power generated by converter 4 into AC power at the commercial frequency when the commercial AC power supply 30 is intact. When the commercial AC power supply 30 fails, inverter 8 converts the DC power supplied from battery 32 via bidirectional chopper 7 into AC power at the commercial frequency.

[0047] Terminal 1 of reactor 9 is connected to the output node of inverter 8, and terminal 2 is connected to output terminal T3 via switch S3. Capacitor 10 is connected to terminal 2 of reactor 9. Capacitor 10 and reactor 9 together constitute AC filter 11.

[0048] AC filter 11 is a low-pass filter that allows commercial frequency AC current to flow from inverter 8 to load 31, preventing the switching frequency signal generated by inverter 8 from passing through to load 31. In other words, AC filter 11 transforms the rectangular wave voltage output from inverter 8 into a sinusoidal wave voltage.

[0049] Current detector 13 detects the current (output current of inverter 8) I2 flowing from power module P to load 31 and sends a signal φI2 representing its detected value to control circuit 14. Current detector 13 corresponds to an embodiment of "second current detector".

[0050] Switch S3 is controlled by control circuit 14. Control circuit 14 turns on switch S3 when the corresponding power module P is set to the operating state, and turns off switch S3 when the corresponding power module P is set to the stop state.

[0051] The control circuit 14 may be configured as, for example, a microcomputer. As an example, the control circuit 14 may have a built-in memory (not shown) and a CPU, and the control actions described later can be executed by the CPU executing software processing of a program pre-stored in the memory. Alternatively, some or all of the control actions may be implemented using hardware processing, such as built-in dedicated electronic circuits, instead of software processing.

[0052] Control circuit 14 is interconnected with the control circuits 14 of other power modules P and the control circuits 28 of bypass module B0 via communication line 15, exchanging information with them. The multiple control circuits 14 and 28 contained in the multiple power modules P1 to Pn constitute a single control device for controlling the uninterruptible power supply device 100. In the following description, the power module P to which each control circuit 14 belongs is sometimes referred to as "this device," and power modules P to which the control circuit 14 does not belong are sometimes referred to as "other devices."

[0053] In each power module P, the control circuit 14 receives signals from the control circuit 28 via the communication line 15, representing the detected values ​​of AC voltage VI, battery voltage VB, and AC voltage VO. Based on these received signals, the output signals φI1 and φI2 of the current detectors 12 and 13, and the detected value of DC voltage VD, the control circuit 14 controls the corresponding power module P.

[0054] Specifically, control circuit 14 determines whether the commercial AC power supply 30 is intact or has experienced a power outage based on a signal indicating the detected value of AC voltage VI. When the commercial AC power supply 30 is intact, control circuit 14 controls converter 4 and inverter 8 synchronously with AC voltage VI based on signals indicating the detected values ​​of AC voltage VI, VO, and DC voltage VD. Furthermore, control circuit 14 controls bidirectional chopper 7 based on a signal indicating the detected value of battery voltage VB.

[0055] On the other hand, when the commercial AC power supply 30 fails, the control circuit 14 controls the inverter 8 and the bidirectional chopper 7 based on the signal indicating the detected value of AC voltage VO, the signal indicating the detected value of battery voltage VB, and the detected value of DC voltage VD.

[0056] like Figure 2 As shown, in the uninterruptible power supply device 100 of this embodiment, voltage detectors 22, 24, and 26 installed in the bypass module B0 detect the instantaneous values ​​of the AC voltage VI supplied to the input terminal T1 of each power module P, the battery voltage VB supplied to the battery terminal T2, and the AC voltage VO presented at the output terminal T3, respectively. The control circuit 28 of the bypass module B0 sends signals representing the detected values ​​of the AC voltage VI, VO, and battery voltage VB to the control circuit 14 of each power module P via the communication line 15. The control circuit 14 of each power module P controls the device based on the received signals.

[0057] That is, voltage detectors 22, 24, and 26 are shared by multiple power modules P1 to Pn. This reduces the number of voltage detectors required for each power module P, thus reducing the size and cost of the power module P. As a result, miniaturization and cost reduction of the uninterruptible power supply device 100 can be achieved.

[0058] Furthermore, in the above structure, the voltage detectors used to detect the DC voltage VD presented in the DC line 6 of each power module P are not shared among the multiple power modules P1 to Pn, but are set up for each power module P. This is to enable hot-swapping of the power modules P while they are still being powered by the uninterruptible power supply 100.

[0059] In detail, when power module P is replaced, while keeping other power modules P in operation, the operation of this power module P is stopped. At this time, in this power module P, by stopping the operation of converter 4, the DC voltage VD is reduced to 0V. Therefore, the DC voltage VD of this power module P becomes a different value from the DC voltage VD of the other power modules P in operation. In this way, since the DC voltage VD varies for each power module P, the voltage detector used to detect the DC voltage VD is not shared among multiple power modules P1 to Pn.

[0060] Figure 3 This is a diagram that roughly represents the functional structure of control circuit 28 and control circuit 14.

[0061] like Figure 3 As shown, the control circuit 28 includes a control unit 50 and a communication unit 52. The communication unit 52 is connected to the control circuit 14 of the power modules P1 to Pn via a communication line 15.

[0062] The control unit 50 sends signals indicating the detection values ​​of voltage detectors 22, 24, and 26 to the control circuits 14 of power modules P1 to Pn via the communication unit 52. The control unit 50 receives, via the communication unit 52, fault detection signals indicating faults in the device and signals indicating the minimum number of power modules P required to operate (Nmin) in order to supply power to the load 31.

[0063] The control unit 50 disconnects switch 20 in inverter power supply mode and connects switch 20 in bypass power supply mode. Furthermore, the user of the uninterruptible power supply device 100 can select either bypass power supply mode or inverter power supply mode by operating an operation unit (not shown).

[0064] However, in inverter power supply mode, if the number of operable power modules P is lower than the lower limit of Nmin due to the failure of at least one power module P, the control unit 50 turns on the switch 20 to supply AC power from the commercial AC power supply 30 to the load 31.

[0065] The control circuit 14 includes an arithmetic unit 40, a discrimination unit 41, a storage unit 42, a detection unit 43, a communication unit 44, and a control unit 45. The arithmetic unit 40 transmits the output signal φI2 of the current detector 13 of this device to the control circuits 14 of (n-1) other devices via the communication unit 44 and communication line 15. The arithmetic unit 40 receives the output signals φI2 of the current detectors 13 of (n-1) other devices via the communication unit 44. Based on the output signals φI2 of the n current detectors 13, the arithmetic unit 40 calculates the current number N of operating power modules P and provides the calculated number N to the discrimination unit 41.

[0066] Furthermore, the calculation unit 40 calculates the total output current of the inverters 8 of the n power modules P1 to Pn based on the output signals φI2 of the n current detectors 13, which is the load current IL supplied from the power modules P1 to Pn to the load 31. The calculation unit 40 calculates the minimum number of power modules P required to operate, Nmin, in order to supply the load current IL. The calculation unit 40 calculates the appropriate number of operating modules Ns by adding the redundant number of operating modules Nr (e.g., 1 module) to the calculated minimum number of operating modules Nmin. The calculation unit 40 provides the calculated appropriate number of operating modules Ns to the determination unit 41.

[0067] By operating the power module P with the appropriate number of operating units Ns obtained by adding the lower limit number of operating units Nmin to the redundant number of operating units Nr, the faulty power module P can be replaced while the power module P with the lower limit number of operating units Nmin continues to supply power to the load 31 in the event that one power module P fails.

[0068] The storage unit 42 stores the priority order of the operating status of power modules P1 to Pn. The priority order is set, for example, according to the numerical order of the power modules P. The priority order can be written into the storage unit 42 by the user of the uninterruptible power supply device 100 operating the operation unit.

[0069] The detection unit 43 detects whether there is a fault in this device, and outputs a fault detection signal if the device is faulty.

[0070] Based on the current number of operating units N and the appropriate number of operating units Ns calculated by the calculation unit 40, the fault detection signal from the detection unit 43, and the operating priority stored in the storage unit 42, the discrimination unit 41 determines whether to set the device to an operating state or a stopped state, and sends a signal indicating its discrimination result to the control unit 45. Furthermore, the discrimination unit 41 sends the signal indicating the discrimination result and the fault detection signal via the communication unit 44 to the control circuit 14 of other devices and the control circuit 28 of the bypass module B0.

[0071] When the detection unit 41 outputs a fault detection signal from the detection unit 43 of this device, it determines that the device should be set to a stop state. Furthermore, if the current number of operating units N is greater than the appropriate number of operating units Ns, the determination unit 41 determines that the number of operating units N should be reduced. In this case, the determination unit 41 determines whether to set the device to a stop state or an operating state based on the device's priority. On the other hand, if the current number of operating units N is less than the appropriate number of operating units Ns, the determination unit 41 determines that the number of operating units N should be increased. In this case, the determination unit 41 determines whether to set the device to an operating state or a stop state based on the device's priority.

[0072] The communication unit 44 transmits the signals received from the control circuit 28 of the bypass module B0, which represent the detected values ​​of AC voltage VI, VO and battery voltage VB, to the control unit 45.

[0073] Voltage detector 16 detects the DC voltage VD of DC line 6 and sends a signal representing its detected value to control unit 45. Voltage detector 16 corresponds to an embodiment of "fourth voltage detector".

[0074] When the determination unit 41 determines that the device should be set to a stop state, the control unit 45 stops the operation of the converter 4, inverter 8 and bidirectional chopper 7 of the device and opens the switch S3.

[0075] On the other hand, when the determination unit 41 determines that the device should be set to an operating state, the control unit 45 operates the converter 4, inverter 8, and bidirectional chopper 7 of the device, and turns on the switch S3. At this time, the control unit 45 controls the converter 4 based on the signal indicating the detected value of AC voltage VI provided by the communication unit 44, the output signal of voltage detector 16, and the output signal φI1 of current detector 12, so that the DC voltage VD output from the converter 4 becomes the reference DC voltage VDr. In addition, the control unit 45 controls the inverter 8 synchronously with the AC voltage VI from the commercial AC power supply 30 based on the signals indicating the detected values ​​of AC voltage VI and VO provided by the communication unit 45 and the output signal φI2 of current detector 13, to generate an AC voltage VO at the commercial frequency. Furthermore, the control unit 45 controls the bidirectional chopper 7 based on the signal indicating the detected value of battery voltage VB provided by the communication unit 44, so that the battery voltage VB becomes the reference battery voltage VBr.

[0076] Furthermore, based on the output signal φI2 of the current detectors 13 of the power modules P1 to Pn, the control unit 45 calculates the current number N of the uninterruptible power supply device 100 in operation and the total output current of the inverters 8 of the power modules P1 to Pn, i.e., the load current IL. The control unit 45 then calculates the shared current ID = IL / N for this device and controls the converter 4 and inverter 8 of this device so that the output current I2 of the inverter 8 becomes the shared current ID.

[0077] Furthermore, the control unit 45 determines whether the AC voltage VI is being normally supplied from the commercial AC power supply 30 based on a signal indicating the detected value of AC voltage VI provided by the communication unit 44. If the AC voltage VI is lower than the lower limit, the control unit 45 determines that the AC voltage VI is not being supplied normally and a power outage has occurred, and stops the operation of the converter 4. Next, the control unit 45 determines whether the DC power of the battery 32 has decreased compared to the lower limit based on a signal indicating the detected value of battery voltage VB provided by the communication unit 44. If it is determined that the DC power of the battery 32 has decreased compared to the lower limit, the control unit 45 stops the operation of the inverter 8 and opens the switch S3.

[0078] In addition, the determination of whether the AC voltage VI is being supplied normally from the commercial AC power supply 30, and the determination of whether the DC power of the battery 32 is lower than the lower limit, can also be performed by the control circuit 28 of the bypass module B0 based on the output signal of the voltage detector 22, and the signal indicating its determination result is sent to the control circuit 14 of each power module P via the communication line 15.

[0079] Figure 4 yes Figure 3 The functional block diagram of the control unit 45 shown.

[0080] like Figure 4 As shown, the control unit 45 includes a converter control unit for controlling the converter 4 and an inverter control unit for controlling the inverter 8.

[0081] The converter control unit includes subtractors 60 and 64, a voltage control unit 62, a current control unit 66, an adder 68, and a PWM circuit 70. Subtractor 60 calculates the deviation ΔVD between the reference DC voltage VDr and the detected value of the DC voltage VD obtained by voltage detector 16. Voltage control unit 62 calculates a current command value I1* to control the current I1 flowing into converter 4, so that the deviation ΔVD becomes 0. Voltage control unit 62 calculates the current command value I1*, for example, by performing a proportional operation or a proportional-integral operation on the deviation ΔVD.

[0082] Subtractor 64 calculates the deviation ΔI1 between the current command value I1* and the detected value of current I1 obtained by current detector 12. Current control unit 66 calculates the voltage command value VI# as the voltage to be applied to reactor 2 to make the deviation ΔI1 zero. Current control unit 66 calculates the voltage command value VI#, for example, by performing a proportional operation or a proportional-integral operation on the deviation ΔI1.

[0083] Adder 68 adds the voltage command value VI# to the detected value of the AC voltage VI provided from communication unit 44 to generate a voltage command value VI*. Based on the voltage command value VI*, PWM circuit 70 outputs a signal that makes the detected value of the AC voltage VI provided from communication unit 44 equal to the voltage command value VI*. This signal is used to drive the semiconductor switching elements included in converter 4.

[0084] The inverter control unit includes subtractors 72 and 76, a voltage control unit 74, a current control unit 78, and a PWM circuit 80. Subtractor 72 calculates the deviation ΔVO between the detected value of AC voltage VI provided from communication unit 44 and the detected value of AC voltage VO provided from communication unit 44. Voltage control unit 74 calculates a current command value I2# to control the output current I2 of inverter 8 so that the deviation ΔVO becomes zero. Voltage control unit 74 generates a current command value I2* based on the current command value I2# and the shared current ID of the device.

[0085] Subtractor 76 calculates the deviation ΔI2 between the current command value I2* and the detected current I2 obtained by current detector 13. Current control unit 78 calculates the voltage command value VO* as the voltage that the inverter 8 should output to make the deviation ΔI2 zero. Current control unit 78 calculates the voltage command value VO*, for example, by performing a proportional operation or a proportional-integral operation on the deviation ΔI2.

[0086] The PWM circuit 80 outputs a signal based on the voltage command value VO*, which makes the detected value of the AC voltage VO provided from the communication unit 44 equal to the voltage command value VO*. This signal is used to drive the semiconductor switching elements included in the inverter 8.

[0087] As explained above, the uninterruptible power supply device 100 of this embodiment is a modular uninterruptible power supply device, comprising multiple power modules P1 to Pn connected in parallel between the commercial AC power supply 30 and the load 31, and a bypass module B0. The bypass module B0 has voltage detectors 22, 24, and 26 for respectively detecting the AC voltage VI applied to the input terminal T1 of each power module P, the battery voltage VB applied to the battery terminal T2, and the AC voltage VO output to the output terminal T3. The control circuit 28 of the bypass module B0 transmits signals representing the detection values ​​of the voltage detectors 22, 24, and 26 to the control circuits 14 of each power module P via communication lines 15.

[0088] By placing voltage detectors 22, 24, and 26, used to detect the voltages required for controlling the converter 4, inverter 8, and bidirectional chopper 7 contained in each power module P, in the bypass module B0, a structure is formed in which voltage detectors 22, 24, and 26 are shared among multiple power modules P1 to Pn. This reduces the number of voltage detectors required for each power module P, thus reducing the size and cost of the power module P. Consequently, miniaturization and cost reduction of the uninterruptible power supply device 100 can be achieved.

[0089] Furthermore, according to the above structure, since the control circuit 14 of each power module P uses a voltage detection value shared among the multiple power modules P1 to Pn to control the converter 4, the bidirectional chopper 7, and the inverter 8, it is possible to suppress operational deviations among the multiple power modules P1 to Pn. For example, it is possible to suppress the occurrence of cross-current between the output terminals T3 of the multiple power modules P1 to Pn due to the output voltage VO deviation of the inverter 8 of the multiple power modules P.

[0090] Furthermore, in the above structure, the voltage detector 16 used to detect the DC voltage VD presented in the DC line 6 of each power module P is not shared among the multiple power modules P1 to Pn, but is set up for each power module P. Therefore, hot-swapping of the power module P can be achieved while the uninterruptible power supply device 100 continues to supply power.

[0091] The embodiments disclosed herein are illustrative in all respects and should not be considered limiting. The invention is defined not by the foregoing description but by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0092] Label Explanation

[0093] 4. Converter; 1, 5, 10. Capacitors; 2, 9. Reactors; 3, 11. AC filters; 6. DC line; 7. Bidirectional chopper; 8. Inverter; 12, 13. Current detectors; 14, 28. Control circuits; 15. Communication line; 16, 22, 24, 26. Voltage detectors; 20. S1-S3 switches; 30. Commercial AC power supply; 31. Load; 32. Battery (power storage device); 40. Calculation unit; 41. Discrimination unit; 42. Storage unit; 43. Detection unit; 44, 52. Communication unit; 45, 50. Control unit; 60, 64, 72, 76. Subtractors; 62, 74. Voltage control unit; 66, 78. Current control unit; 68. Adder; 70, 80. PWM circuit; 100. Uninterruptible power supply; B0. Bypass module; P1-Pn, P power module; T1, T11. Input terminals; T2, T12. Battery terminals; T3, T13. Output terminals.

Claims

1. An uninterruptible power supply device, characterized in that, have: Multiple power conversion modules are connected in parallel between the AC power source and the load; and A bypass module is connected between the aforementioned AC power supply and the aforementioned load; The aforementioned power conversion modules are connected in parallel relative to the power storage device; Each power conversion module includes: Terminal 1 receives AC power from the aforementioned AC power source; The second terminal is connected to the aforementioned power storage device; The third terminal is used to output AC power to the aforementioned load; The converter converts the AC power received at the first terminal into DC power. The inverter converts DC power from the aforementioned converter or power storage device into AC power and supplies it to the aforementioned load; and The first control circuit controls the converter and the inverter mentioned above. The bypass module mentioned above includes: The first switch is connected between the AC power source and the load. The first voltage detector detects the AC voltage applied to the first terminal mentioned above; The second voltage detector detects the DC voltage applied to the second terminal mentioned above; The third voltage detector detects the AC voltage applied to the aforementioned third terminal; and The second control circuit controls the opening and closing of the first switch mentioned above; The second control circuit is communicatively connected to the first control circuit and sends the detection results of the first to third voltage detectors to the first control circuit. The first control circuit uses the detection results of the first to third voltage detectors sent from the second control circuit to control the converter and the inverter.

2. The uninterruptible power supply device as described in claim 1, characterized in that, The aforementioned power conversion modules also include: The fourth voltage detector detects the DC voltage of the DC line connected to the aforementioned converter and inverter. The first current detector detects the input current flowing to the aforementioned converter; and The second current detector detects the output current of the inverter mentioned above; The first control circuit uses the detection results of the first to third voltage detectors, the detection results of the fourth voltage detector, and the detection results of the first and second current detectors sent from the second control circuit to control the converter and the inverter.

3. The uninterruptible power supply device as described in claim 2, characterized in that, Each of the aforementioned power conversion modules also includes a bidirectional chopper for exchanging DC power between the aforementioned power storage device and the aforementioned DC line; The first control circuit uses the detection result of the fourth voltage detector and the detection result of the second voltage detector sent from the second control circuit to control the bidirectional chopper.

4. The uninterruptible power supply device as described in any one of claims 1 to 3, characterized in that, Each of the aforementioned power conversion modules also includes a second switch connected between the aforementioned inverter and the aforementioned third terminal; When the first control circuit sets the corresponding power conversion module to the stop state, it stops the operation of the converter and the inverter and disconnects the second switch.

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