JP5591247B2 - Power conversion system and uninterruptible power supply system - Google Patents

Description

  The present invention relates to a power conversion system and an uninterruptible power supply system, and particularly to a power conversion system and an uninterruptible power supply system including a plurality of power converters connected in parallel.

  Conventionally, an uninterruptible power supply system in which a load is driven by a plurality of uninterruptible power supply apparatuses connected in parallel is known. In the conventional first uninterruptible power supply system, the load current is equally shared by all uninterruptible power supply devices to drive the load. In this system, even if one uninterruptible power supply fails, the load can be driven by the remaining uninterruptible power supply.

  Further, as disclosed in, for example, Japanese Patent Laid-Open No. 3-124228 (Patent Document 1) and Japanese Utility Model Laid-Open No. 4-51044 (Patent Document 2), in the conventional second uninterruptible power supply system, the load current is reduced. Accordingly, the number of uninterruptible power supply units to be operated is changed.

JP-A-3-124228 Japanese Utility Model Publication 4-51044

  However, the first uninterruptible power supply system has a problem that a loss occurs in each of the plurality of uninterruptible power supply apparatuses and the efficiency is low.

  Further, in the second uninterruptible power supply system, for example, the uninterruptible power supply that is operated when the number of operating units is one is fixed. However, there is a problem that failure is likely to occur in an uninterruptible power supply that is continuously operated only.

  Whether or not the uninterruptible power supply is out of order is not known unless it is actually operated. Therefore, when there is an uninterruptible power supply that has failed while it is left unattended for a long period of time, there is also a problem that the discovery of the failure is delayed.

  Therefore, a main object of the present invention is to provide a power conversion system and an uninterruptible power supply system that are highly efficient, have few failures, and can quickly find a failure.

  The power conversion system according to the present invention includes a plurality of power conversion devices that are connected in parallel between a power source and a load, each of which converts first power supplied from the power source to second power and supplies the second power to the load. The number of power conversion devices necessary for converting the first power to the second power among the plurality of power conversion devices is selected, each selected power conversion device is operated, and each remaining power conversion device And a control unit for stopping the operation. This control part changes the power converter device to drive | operate with a predetermined period so that the operation time of several power converter devices may become mutually equal.

  The uninterruptible power supply system according to the present invention includes a plurality of uninterruptible power supplies connected in parallel between a commercial AC power supply and a load, and each uninterruptible power supply is a first supplied from the commercial AC power supply. A converter that converts AC power into DC power and an inverter that converts DC power into second AC power are included. The uninterruptible power supply system further includes a control unit that selects a required number of inverters to drive a load among the plurality of inverters, operates the selected inverters, and stops the remaining inverters. The control unit changes the inverter to be operated at a predetermined cycle so that the operation times of the plurality of inverters are equal to each other.

  Further, another uninterruptible power supply system according to the present invention is provided in common to a plurality of uninterruptible power supplies connected in parallel between a commercial AC power supply and a load, and the plurality of uninterruptible power supplies, Each uninterruptible power supply includes a converter that converts first AC power supplied from a commercial AC power source into DC power, and DC power supplied from the converter or the power storage device. And an inverter for converting into two AC power. The power storage device stores DC power generated by each converter of the plurality of uninterruptible power supply devices. The uninterruptible power supply system further includes a control unit that selects a required number of converters to drive a load among the plurality of converters, operates the selected converters, and stops the remaining converters. This control unit changes the converter to be operated at a predetermined cycle so that the operation times of the plurality of converters are equal to each other.

  Still another uninterruptible power supply system according to the present invention includes a plurality of uninterruptible power supplies and a power storage device that is provided in common to the plurality of uninterruptible power supplies and stores DC power. . The input nodes of the plurality of uninterruptible power supply devices are all connected to a commercial AC power source, and the output nodes are respectively connected to a plurality of loads. Each uninterruptible power supply includes a converter that converts first AC power supplied from a commercial AC power source to DC power, an inverter that converts DC power supplied from the converter or the power storage device to second AC power, and The power storage device stores DC power generated by each converter of the plurality of uninterruptible power supply devices. The uninterruptible power supply system further includes a control unit that selects a required number of converters to drive a plurality of loads among the plurality of converters, operates the selected converters, and stops the remaining converters. Prepare. This control unit changes the converter to be operated at a predetermined cycle so that the operation times of the plurality of converters are equal to each other.

  Further, in another uninterruptible power supply system according to the present invention, one terminal receives AC power from a commercial AC power supply, the other terminal is connected to a load, and AC power is supplied from the commercial AC power supply in a normal state. Connected in parallel to the switch that becomes non-conductive at the time of power failure when the supply of AC power from the commercial AC power supply is stopped and the other terminal of the switch, and each is supplied via the switch from the commercial AC power supply when normal A plurality of power converters that convert the AC power to be converted into DC power and supply it to the power storage device, convert the DC power of the power storage device to AC and supply it to the load in the event of a power failure, and a plurality of power converter devices A control unit is provided that selects the number of power conversion devices necessary for driving the load, operates each selected power conversion device, and stops the remaining power conversion devices. This control part changes the power converter device to drive | operate with a predetermined period so that the operation time of several power converter devices may become mutually equal.

  As described above, in the power conversion system according to the present invention, the number of power conversion devices necessary for converting the first power into the second power is selected, each selected power conversion device is operated, and the remaining power is converted. A control unit that stops each of the power conversion devices is provided, and the control unit changes the power conversion devices to be operated at a predetermined cycle so that the operation times of the plurality of power conversion devices are equal to each other. Therefore, the continuous operation time of each power converter can be shortened, and the failure of the power converter can be reduced. In addition, it is possible to quickly find a power converter that has failed during a stop. Further, since the number of operating units is changed according to the load current, the efficiency can be increased.

  Further, in another uninterruptible power supply system according to the present invention, a required number of inverters for driving a load among a plurality of inverters are selected, the selected inverters are operated, and the remaining inverters are stopped. A control unit is provided, and the control unit changes the inverter to be operated at a predetermined cycle so that the operation times of the plurality of inverters are equal to each other. Therefore, the continuous operation time of each inverter can be shortened, and the failure of the inverter can be reduced. In addition, it is possible to quickly find an inverter that has failed during a stop. Further, since the number of operating units is changed according to the load current, the efficiency can be increased.

  In yet another uninterruptible power supply system according to the present invention, the number of converters necessary for driving the load among a plurality of converters is selected, the selected converters are operated, and the remaining converters are stopped. The control unit is configured to change the converter to be operated at a predetermined cycle so that the operation times of the plurality of converters are equal to each other. Therefore, the continuous operation time of each converter can be shortened, and converter failures can be reduced. Moreover, the converter which failed during the stop can be found quickly. Further, since the number of operating units is changed according to the load current, the efficiency can be increased.

  In yet another uninterruptible power supply system according to the present invention, the number of power conversion devices necessary for driving a load among a plurality of power conversion devices is selected, and each selected power conversion device is operated. A control unit that stops each remaining power conversion device is provided, and this control unit changes the power conversion device to be operated at a predetermined cycle so that the operation times of the plurality of power conversion devices are equal to each other. Therefore, the continuous operation time of each power converter can be shortened, and the failure of the power converter can be reduced. In addition, it is possible to quickly find a power converter that has failed during a stop. Further, since the number of operating units is changed according to the load current, the efficiency can be increased.

It is a circuit block diagram which shows the structure of the uninterruptible power supply system by Embodiment 1 of this invention. It is a circuit block diagram which shows the structure of the control part shown in FIG. It is a figure which shows the table stored in the memory | storage part shown in FIG. It is a time chart which illustrates operation | movement of the uninterruptible power supply system shown in FIG. 5 is a diagram illustrating a modification example of the first embodiment. FIG. FIG. 10 is a circuit block diagram illustrating another modification of the first embodiment. FIG. 10 is a circuit block diagram showing still another modification of the first embodiment. FIG. 10 is a circuit block diagram showing still another modification of the first embodiment. FIG. 10 is a circuit block diagram showing still another modification of the first embodiment. FIG. 10 is a circuit block diagram showing still another modification of the first embodiment. FIG. 10 is a circuit block diagram showing still another modification of the first embodiment. It is a circuit block diagram which shows the structure of the uninterruptible power supply system by Embodiment 2 of this invention. It is a circuit block diagram which shows the structure of the frequency conversion system by Embodiment 3 of this invention. It is a circuit block diagram which shows the structure of the power conversion system by Embodiment 4 of this invention. FIG. 10 is a circuit block diagram showing a modification of the fourth embodiment. It is a circuit block diagram which shows the structure of the power conversion system by Embodiment 5 of this invention. FIG. 10 is a circuit block diagram showing a modification of the fifth embodiment. FIG. 20 is a circuit block diagram showing another modification of the fifth embodiment. It is a circuit block diagram which shows the structure of the power converter device by Embodiment 6 of this invention. FIG. 22 is a circuit block diagram showing a modification of the sixth embodiment.

[Embodiment 1]
As shown in FIG. 1, the uninterruptible power supply system according to the first embodiment includes a plurality (three in the figure) of uninterruptible power supply devices U1 to U3, a current sensor 4, and a control unit 5. The uninterruptible power supply devices U1 to U3 are connected in parallel between the commercial AC power supply 70 and the load 71. Each of uninterruptible power supplies U1-U3 includes a converter 1, a battery 2, and an inverter 3. The input nodes of the three converters 1 are commonly connected to the node N1, and the node N1 is connected to the commercial AC power supply 70. Converter 1 converts commercial AC power from commercial AC power supply 70 into DC power. Battery 2 stores the DC power generated by converter 1. Inverter 3 converts DC power supplied from converter 1 or battery 2 into AC power. The output nodes of the three inverters 3 are commonly connected to the node N2. Node N2 is connected to load 71.

  When AC power is supplied from the commercial AC power supply 70, DC power generated by the converter 1 is stored in the battery 2, supplied to the inverter 3, and AC power generated by the inverter 3 is supplied to the load 71. Is done. When the supply of AC power from the commercial AC power supply 70 is stopped (at the time of a power failure), the converter 1 is stopped, the DC power stored in the battery 2 is supplied to the inverter 3, and the AC power generated by the inverter 3 Is supplied to a load 71. Therefore, the load 71 can be driven even during a power failure during the period in which the DC power is stored in the battery 2.

  The current sensor 4 detects a current flowing from the node N2 to the load 71, and gives a signal indicating the detected current value to the control unit 5. Based on the output signal of the current sensor 4, the control unit 5 obtains the number of uninterruptible power supply units (for example, one unit) necessary for driving the load 71, and only that number of uninterruptible power supply units (for example, U1). And the remaining uninterruptible power supply devices (in this case, U2 and U3) are stopped.

  Moreover, the control part 5 changes the uninterruptible power supply apparatus to operate | operate with a predetermined period so that the operation time of several uninterruptible power supply apparatuses U1-U3 may become equal. For example, the control unit 5 changes the uninterruptible power supply to be operated at a cycle of one day, and operates the three uninterruptible power supply units U1 to U3 one by one in order. The control unit 5 is included in each control unit (not shown) of the uninterruptible power supply units U1 to U3, and the three uninterruptible power supply units U1 to U1 are controlled by the control unit 5 of one uninterruptible power supply unit. U3 may be controlled.

  As shown in FIG. 2, the control unit 5 includes comparison circuits 11 and 12, an operation number determination unit 13, a timer 14, a storage unit 15, a failure detection unit 16, and an operation command unit 17. The comparison circuit 11 compares the load current I detected by the current sensor 4 with the threshold current Ith1 corresponding to 33% of the rated current. Output signal φ11 of comparison circuit 11 is set to “L” level when load current I is lower than threshold current Ith1, and is set to “H” level when load current I is higher than threshold current Ith1. The

  The comparison circuit 12 compares the load current I detected by the current sensor 4 with the threshold current Ith1 corresponding to 66% of the rated current. Output signal φ12 of comparison circuit 12 is set to “L” level when load current I is lower than threshold current Ith2, and is set to “H” level when load current I is higher than threshold current Ith2. The

  The number of operating units determining unit 13 determines the number of operating uninterruptible power supply units based on the output signals φ11 and φ12 of the comparison circuits 11 and 12. When both signals φ11 and φ12 are at the “L” level, load current I is smaller than 33% of the rated current, so the number of operating uninterruptible power supply units is determined to be one. Further, when the signals φ11 and φ12 are at “H” level and “L” level, respectively, the load current I is larger than 33% and smaller than 66% of the rated current, so the number of operating uninterruptible power supply units is Two units will be decided. When signals φ11 and φ12 are both at “H” level, load current I is greater than 66% of the rated current, so the number of uninterruptible power supply units to be operated is determined to be three.

  The timer 14 includes a counter that counts the number of pulses of the clock signal CLK. When the count values of the counter are 0, 1, and 2, the timer 14 outputs signals indicating periods T1, T2, and T3, respectively. If a pulse of the clock signal CLK is input when the count value of the counter is 2, the count value of the counter returns to 0.

The storage unit 15 stores the table shown in FIG. Periods T1, T2, and T3 are shown in the uppermost column of the table, and the numbers U1, U2, and U3 of the uninterruptible power supply units that are operated in the periods T1, T2, and T3 when the number of operating units is one are shown in the second column. It is shown. The third column shows the numbers U2, U3, U1 of the other uninterruptible power supply units operated at T1, T2, T3 during the period when the number of operating units is two, and the fourth column The numbers U3, U1 and U2 of the other uninterruptible power supply units operated in the periods T1, T2 and T3 when the number of operating units is three are shown.

  The operation command unit 17 refers to the table stored in the storage unit 15 to operate the number of uninterruptible power supply devices determined by the operation number determination unit 13. That is, the operation command unit 17 operates the uninterruptible power supply devices U1 to U3 in the periods T1 to T3 indicated by the output signal of the timer 14 when the operation number is determined to be one by the operation number determination unit 13. . Further, when the number of operating units is determined to be two by the operating unit determining unit 13, the operation commanding unit 17 is connected to the uninterruptible power supply devices U1 and U2, respectively in the periods T1, T2, and T3 indicated by the output signal of the timer 14. U2 and U3, U3 and U1 are operated. Further, when the number of operating units is determined to be three by the operating unit determining unit 13, the operation command unit 17 includes three uninterruptible power supply devices U1 regardless of the periods T1 to T3 indicated by the output signal of the timer 14. Operate ~ U3.

  The operation command unit 17 also operates the uninterruptible power supply according to the table in FIG. 3 even when the number of operating units is changed by the operating unit determining unit 13 in a certain period. For example, when the number of operating units is changed from three to two in the period T1, the uninterruptible power supply U3 among the three uninterruptible power supplies U1 to U3 that have been operating is stopped. Further, when the number of operating units is changed from one to two in the period T2, the uninterruptible power supply U3 is operated in addition to the uninterruptible power supply U2 being operated.

  Moreover, the failure detection unit 16 detects the presence or absence of each failure of the uninterruptible power supply devices U1 to U3, and gives a signal indicating the detection result to the operation command unit 17. For example, when a failure of one uninterruptible power supply (for example, U1) is detected by the failure detection unit 16 and the number of operating units is determined to be 1 by the operating unit determining unit 13, regardless of the output signal of the timer 14 The remaining two uninterruptible power supply devices (in this case, U2 and U3) are alternately operated at a predetermined cycle. Further, when a failure of one uninterruptible power supply (for example, U1) is detected by the failure detection unit 16 and the number of operating units is determined to be 2 by the operating unit determining unit 13, the output signal of the timer 14 is not relevant. Two uninterruptible power supply units (in this case, U2 and U3) are operated.

  FIG. 4 is a time chart illustrating the operation of the uninterruptible power supply system. At a certain time t0, the operation of the three uninterruptible power supply devices U1 to U3 is started, and the load current I is detected. Load current I and threshold currents Ith1 and Ith2 are compared, and the number of uninterruptible power supply units to be operated is determined based on the comparison result. Here, it is assumed that one is determined.

  At time t1, the count value of the counter in the timer 14 is reset to 0, and a signal indicating the period T1 is output from the timer 14. The operation command unit 17 refers to the table of FIG. 3 to operate only the uninterruptible power supply device U1 and stops the remaining uninterruptible power supply devices U2 and U3.

  At time t2, the count value of the counter in the timer 14 is incremented (+1) to 1 and a signal indicating the period T2 is output from the timer 14. The operation command unit 17 operates the uninterruptible power supply device U2 with reference to the table of FIG. 3, and then stops the remaining uninterruptible power supply devices U3 and U1.

  At time t3, the count value of the counter in the timer 14 is incremented (+1) to become 2, and a signal indicating the period T3 is output from the timer 14. The operation command unit 17 refers to the table in FIG. 3 and operates the uninterruptible power supply U3, and then stops the remaining uninterruptible power supply U1 and U2.

  At time t4, the count value of the counter in the timer 14 is reset to 0, and a signal indicating the period T1 is output from the timer 14. The operation command unit 17 refers to the table of FIG. 3 and operates the uninterruptible power supply U1 and then stops the remaining uninterruptible power supply U2 and U3.

  Thereafter, it is assumed that the load current I increases and the number of operating units is determined to be 2 by the operating unit determining unit 13. At time t5, the operation command unit 17 starts the operation of the uninterruptible power supply U2 in addition to the uninterruptible power supply U1 with reference to the table of FIG.

  At time t6, the count value of the counter in the timer 14 is incremented (+1) to become 1, and a signal indicating the period T2 is output from the timer 14. The operation command unit 17 refers to the table of FIG. 3 and operates the uninterruptible power supply devices U2 and U3, and then stops the remaining uninterruptible power supply device U1.

  At time t7, the count value of the counter in the timer 14 is incremented (+1) to become 2, and a signal indicating the period T3 is output from the timer 14. The operation command unit 17 refers to the table of FIG. 3 and operates the uninterruptible power supply devices U3 and U1, and then stops the remaining uninterruptible power supply device U2.

  In the first embodiment, the number of uninterruptible power supply units required for driving the load 71 among the three uninterruptible power supply units U1 to U3 is selected and each selected uninterruptible power supply unit is operated. Stop each remaining uninterruptible power supply. Therefore, compared with the case where all the uninterruptible power supply devices U1 to U3 are operated regardless of the load current, the loss generated in the uninterruptible power supply devices U1 to U3 can be reduced and the efficiency can be increased.

  Moreover, the uninterruptible power supply to be operated is changed at a predetermined cycle so that the operation times of the three uninterruptible power supplies U1 to U3 are equal to each other. Therefore, the continuous operation time of each uninterruptible power supply can be shortened, and failure of the uninterruptible power supply can be reduced. In addition, it is possible to quickly find an uninterruptible power supply that has failed during a stop.

[Modification 1]
In the above-described embodiment, the case where three uninterruptible power supply devices U1 to U3 are provided has been described, but the same applies to the case where four or more uninterruptible power supply devices are provided. For example, when four uninterruptible power supply devices U1 to U4 are provided, the timer 14 includes a counter that counts the number of pulses of the clock signal CLK, and when the count value of the counter is 0, 1, 2, 3, respectively. A signal indicating the periods T1, T2, T3, and T4 is output. If a pulse of the clock signal CLK is input when the count value of the counter is 3, the count value of the counter returns to 0.

The storage unit 15 stores the table shown in FIG. Periods T1, T2, T3, and T4 are shown in the uppermost column of the table, and the number U1 of the uninterruptible power supply operated in the periods T1, T2, T3, and T4 when the number of operating units is one in the second column. , U2, U3, U4 are shown. The third column shows the numbers U2, U3, U4, U1 of the other uninterruptible power supply units operated at T1, T2, T3, T4 during the period when the number of operating units is two. The 4th column shows the numbers U3, U4, U1, U2 of the other uninterruptible power supply units operated in the periods T1, T2, T3, T4 when the number of operating units is 3, and the 5th column shows The numbers U4, U1, U2, and U3 of the other uninterruptible power supply units operated in the periods T1, T2, T3, and T4 when the number of operating units is four are shown.

  The operation command unit 17 operates the uninterruptible power supply devices U1 to U4 in the periods T1 to T4 indicated by the output signal of the timer 14 when the operation number determination unit 13 determines that the number of operation is one. Further, when the number of operating units is determined to be two by the operating unit determining unit 13, the operation command unit 17 is connected to the uninterruptible power supply U1 in the periods T1, T2, T3, and T4 indicated by the output signal of the timer 14, respectively. U2, U2 and U3, U3 and U4, U4 and U1 are operated.

  Further, when the number of operating units is determined to be 3 by the operating unit determining unit 13, the operation command unit 17 is connected to the uninterruptible power supply U1 in the periods T1, T2, T3, and T4 indicated by the output signal of the timer 14, respectively. U2, U3, U2, U3, U4, U3, U4, U1, U4, U1, and U2 are operated. In addition, when the number of operating units is determined to be four by the operating unit determining unit 13, the operation command unit 17 includes four uninterruptible power supply devices U1 regardless of the periods T1 to T4 indicated by the output signal of the timer 14. Operate U4.

  The storage unit 15 also stores a table when one uninterruptible power supply device fails. For example, the table of FIG. 3 is stored as a table when the uninterruptible power supply U4 breaks down. In this case, the timer 14 outputs a signal indicating the periods T1 to T3 instead of the signal indicating the periods T1 to T4, and the same operation as the system illustrated in FIGS. 1 to 4 is performed. Even in the first modification, the same effect as in the embodiment can be obtained.

[Modification 2]
In the first embodiment, a minimum number of uninterruptible power supply units are driven to drive the load 71. However, in this modified example 2, in addition to this, a backup uninterruptible power supply unit is operated, so-called redundant operation. To do. The operation command unit 17 operates the number of uninterruptible power supply units obtained by adding 1 to the number determined by the operation number determination unit 13. For example, when the load current I is lower than 33% of the rated current, only one uninterruptible power supply is operated in the first embodiment, but in this modified example, two uninterruptible power supplies are operated. . In this case, even if one uninterruptible power supply suddenly fails during operation, the load 71 can be driven by the other uninterruptible power supply. The rotation of the uninterruptible power supply to be operated is performed in the same manner as in the first embodiment.

[Modification 3]
In the first embodiment, the number of uninterruptible power supply units necessary for driving the load 71 is selected according to the load current I, the selected uninterruptible power supply units are operated, and the remaining uninterruptible power supply units are operated. The uninterruptible power supply to be operated was changed at a predetermined cycle so that the operation times of the three uninterruptible power supplies U1 to U3 were equal to each other. However, when the battery 2 is, for example, a lead storage battery, the battery 2 needs to be constantly charged. Therefore, in the third modification, regardless of the load current I, the converters 1 of the three uninterruptible power supply devices U1 to U3 are always operated, and the three batteries 2 are always charged. Further, the number of inverters 3 necessary for driving the load 71 is selected according to the load current I, the selected inverters 3 are operated, the remaining inverters 3 are stopped, and the three inverters are operated. The inverter 3 to be operated is changed at a predetermined cycle so that the times are equal to each other. The rotation of the inverter 3 to be operated is performed in the same manner as in the first embodiment. In this modified example 3, the failure of the inverter 3 can be reduced. In addition, when the battery 2 is a lithium ion battery, for example, it is not necessary to charge the battery 2 constantly.

[Modification 4]
In this modified example 4, as shown in FIG. 6, one battery 2 is shared by three uninterruptible power supply devices U1 to U3. All three converters 1 charge one battery 2, and DC power is supplied from one battery 2 to three inverters 3. In the fourth modification, the battery 2 can be constantly charged by operating one uninterruptible power supply. Therefore, even when the battery 2 is a lead storage battery that needs to be constantly charged, the number of uninterruptible power supply units corresponding to the load current I can be operated.

[Modification 5]
In this modified example 5, as shown in FIG. 7, a control unit 20 is added to the modified example 4. The control unit 20 has the same configuration as the control unit 5. The control unit 5 controls the operation / stop of the three inverters 3, and the control unit 20 controls the operation / stop of the three converters 1. That is, the control unit 5 selects the number of inverters 3 necessary for driving the load 71 according to the load current I, operates the selected inverters 3 and stops the remaining inverters 3. The inverter 3 to be operated is changed at a predetermined cycle so that the operation times of the inverters 3 are equal to each other. Further, when one inverter 3 fails, the control unit 5 controls the operation / stop of the remaining two inverters 3 so that the operation times of the two inverters 3 are equal to each other. The inverter 3 is changed at a predetermined cycle.

  Similarly, the control unit 20 selects the number of converters 1 necessary for driving the load 71 in accordance with the load current I, operates each selected converter 1 and stops each remaining converter 1, and The converters 1 to be operated are changed at a predetermined cycle so that the operation times of the three converters 1 are equal to each other. In addition, when one converter 1 fails, the control unit 20 controls the operation / stop of the remaining two converters 1 so that the operation times of the two converters 1 are equal to each other. The converter 1 is changed at a predetermined cycle. The rotation of converter 1 to be operated is performed in the same manner as in the first embodiment. Also in this modified example 5, the same effect as in the embodiment can be obtained.

[Modification 6]
In this modified example 6, as shown in FIG. 8, a load 71 and a current sensor 4 are connected to each of the three uninterruptible power supply devices U1 to U3. The three current sensors 4 detect the load currents I1 to I3 of the uninterruptible power supply devices U1 to U3, respectively, and output signals indicating the detected values of the load currents I1 to I3. The adding unit 21 adds the output signals of the three current sensors 4 and gives the control unit 20 a signal indicating the current IA that is the sum of the load currents I1 to I3 of the three uninterruptible power supply devices U1 to U3. The control unit 20 selects the number of converters 1 necessary for driving the three loads 71 according to the current IA, operates the selected converters 1 and stops the remaining converters 1 and 3 units. The converters 1 to be operated are changed at a predetermined cycle so that the operation times of the converters 1 are equal to each other. In addition, when one converter 1 fails, the control unit 20 controls the operation / stop of the remaining two converters 1 so that the operation times of the two converters 1 are equal to each other. The converter 1 is changed at a predetermined cycle. In this modified example 6, the failure of the converter 1 can be reduced.

[Modification 7]
When the load 71 is a computer network server, the increase or decrease in load current is small. In this case, a setting unit for setting the ratio (%) of the load current to the rated current may be provided instead of the current sensor 4. For example, when the ratio of the load current to the rated current is set to 30%, the control unit 5 sequentially operates the three uninterruptible power supply devices U1 to U3 one by one. Thereafter, when the number of servers is increased and the ratio of the load current to the rated current is set to 60%, the control unit 5 sequentially operates the three uninterruptible power supply devices U1 to U3 two by two. Also in this modified example 7, the same effect as in the first embodiment can be obtained.

[Modification 8]
In the second modification, in addition to the minimum number of uninterruptible power supply units required to drive the load 71, a spare uninterruptible power supply unit is operated to perform so-called redundant operation. However, even when the load current I is 50% of the rated current, if it can be handled with one uninterruptible power supply for a short time, redundant operation can be realized by operating two uninterruptible power supplies. . That is, when the two uninterruptible power supply devices U1 and U2 are operating when the load current I is 50% of the rated current, even if one uninterruptible power supply device U1 fails, The operation of the load 71 can be continued by the overload operation of the other uninterruptible power supply U2 for the time until the power failure power supply U3 is activated. If it does in this way, when load current I is 50% of rated current, efficiency will become higher than operating three uninterruptible power supply devices U1-U3.

[Modification 9]
FIG. 9 is a circuit block diagram showing a ninth modification of the first embodiment, which is compared with FIG. Referring to FIG. 9, the modification 9 is different from the first embodiment in that a bidirectional chopper 22 is added to each of the uninterruptible power supply devices U1 to U3. When the AC power is supplied from the commercial AC power supply 70, the bidirectional chopper 22 converts the output voltage (first DC voltage) of the converter 1 into a predetermined second DC voltage and supplies it to the battery 2. When the supply of AC power from the commercial AC power supply 70 is stopped (when a power failure occurs), the output voltage (second DC voltage) of the battery 2 is converted into a predetermined first DC voltage and supplied to the inverter 3. To do.

  In other words, when AC power is supplied from the commercial AC power supply 70, the DC power generated by the converter 1 is stored in the battery 2 by the bidirectional chopper 22, and the DC power generated by the converter 1 is The AC power generated by the inverter 3 is supplied to the load 71. In the event of a power failure, converter 1 is stopped, DC power stored in battery 2 is supplied to inverter 3 by bidirectional chopper 22, and AC power generated by inverter 3 is supplied to load 71. Therefore, the load 71 can be driven even during a power failure during the period in which the DC power is stored in the battery 2. Also in this modified example 9, the same effect as in the first embodiment can be obtained.

[Modification 10]
FIG. 10 is a circuit block diagram showing a tenth modification of the first embodiment, and is a diagram to be compared with FIG. Referring to FIG. 10, this modification 10 is different from modification 7 in that a bidirectional chopper 22 is added to each of the uninterruptible power supply devices U1 to U3. The output nodes of the converter 1 of the uninterruptible power supply devices U1 to U3 are connected to each other. The input node of each bidirectional chopper 22 is connected to the output node of the corresponding converter 1. The positive electrode of the battery 2 is connected to the output node of each bidirectional chopper 22. The operation of the bidirectional chopper 22 is as described in the ninth modification.

The control unit 5 controls the operation / stop of the three inverter 3, the control unit 20 controls the operation / stop of the three converters 1, further control unit 2 0 of the three bidirectional chopper 22 operating / Control the stop. The operation of the control unit 5 is as described in the seventh modification. The operation of the control unit 20 related to the converter 1 is as described in the seventh modification.

  The control unit 20 further selects the number of bidirectional choppers 22 necessary for driving the load 71 based on the load current I, operates the selected bidirectional choppers 22, and operates the remaining bidirectional choppers 22. And the two-way choppers 22 to be operated are changed at a predetermined cycle so that the operation times of the three two-way choppers 22 are equal to each other. In addition, when one of the bidirectional choppers 22 fails, the control unit 20 controls the operation / stop of the remaining two bidirectional choppers 22 so that the operation times of the two bidirectional choppers 22 are equal to each other. The bidirectional chopper 22 to be operated is changed at a predetermined cycle. The rotation of the bidirectional chopper 22 to be operated is performed in the same manner as in the first embodiment. Also in this modified example 10, the same effect as in the first embodiment can be obtained.

[Modification 11]
FIG. 11 is a circuit block diagram showing a modification 11 of the first embodiment, which is compared with FIG. Referring to FIG. 11, the modification 11 is different from the modification 8 in that a bidirectional chopper 22 is added to each of the uninterruptible power supply devices U1 to U3. The output nodes of the converter 1 of the uninterruptible power supply devices U1 to U3 are connected to each other. The input node of each bidirectional chopper 22 is connected to the output node of the corresponding converter 1. The positive electrode of the battery 2 is connected to the output node of each bidirectional chopper 22. The operations of the bidirectional chopper 22 and the control unit 20 are as described in the tenth modification. Also in this modified example 11, the same effect as in the first embodiment can be obtained.

  Needless to say, Embodiment 1 and Modifications 1 to 11 may be appropriately combined.

[Embodiment 2]
FIG. 12 is a circuit block diagram showing a configuration of an uninterruptible power supply system according to Embodiment 2 of the present invention. In FIG. 12, this uninterruptible power supply system includes a plurality (three in the figure) of power conversion devices P1 to P3, a switch SW2, a current sensor 32, and control units 33 and 34. One terminal of the switch SW2 is connected to the node N31, and the node N31 is connected to the commercial AC power supply 70. The other terminal of the switch SW2 is connected to the node N32, and the node N32 is connected to the load 71.

  Each of power conversion devices P1-P3 includes a battery 30, a DC / AC converter 31, and a switch SW1. The positive electrode of the battery 30 is connected to the DC terminal of the DC / AC converter 31. The AC terminal of the DC / AC converter 31 is connected to the node N32 via the switch SW1. When the AC power is supplied from the commercial AC power supply 70, the DC / AC converter 31 converts the AC power into DC power and stores it in the battery 30. During a power failure, the DC / AC converter 31 converts the DC power of the battery 30 to the commercial frequency. Convert to AC power. The battery 30 stores the DC power generated by the DC / AC converter 31.

The control unit 33 detects whether or not AC power is supplied from the commercial AC power supply 70, and gives a signal indicating the detection result to the switch SW2 and the control unit 34. Switch SW2 is controlled by a signal from the control unit 3 3, when the AC power from the commercial AC power source 70 is supplied to conduct, during a power outage is rendered non-conductive. The current sensor 32 detects a current flowing from the node N32 to the load 71, and gives a signal indicating the detected current value to the control unit 34.

  Control unit 34 controls each of power conversion devices P <b> 1 to P <b> 3 based on signals from control unit 33 and current sensor 32. That is, the control unit 34 obtains the number of power conversion devices (for example, one) required to drive the load 71 based on the output signal of the current sensor 4, and determines the number of power conversion devices (for example, P1). Only the selected power converter (in this case, P1) is operated, and the remaining power converters (in this case, P2, P3) are stopped.

  In the power conversion device selected by the control unit 34 (P1 in this case), the switch SW1 is turned on, and the DC / AC converter 31 performs the power conversion operation instructed by the control unit 34. In the power conversion device (in this case, P2 and P3) not selected by the control unit 34, the switch SW1 becomes non-conductive, and the DC / AC converter 31 does not perform the power conversion operation.

  Moreover, the control part 34 changes the power converter device to drive | operate with a predetermined period so that the operation time of several power converter device P1-P3 may become equal. The rotation of the power converter to be operated is performed in the same manner as in the first embodiment. For example, the control part 34 changes the power converter device to drive | operate with a 1-day cycle, and makes the three power converter devices P1-P3 drive one by one in order. The control units 33 and 34 are included in the respective control units (not shown) of the power conversion devices P1 to P3, and the three power conversion devices P1 are controlled by the control units 33 and 34 of one power conversion device. ~ P3 may be controlled.

  When AC power is supplied from the commercial AC power supply 70, the switch SW2 is turned on, and the AC power from the commercial AC power supply 70 is supplied to the load 71 via the switch SW2. In the power converter selected by the control unit 34 (P1 in this case), the switch SW1 is turned on, and the AC power from the commercial AC power supply 70 is supplied to the DC / AC converter 31 via the switch SW1. The DC / AC converter 31 converts AC power into DC power and stores it in the battery 30. In addition, in the power conversion device (in this case, P2 and P3) not selected by the control unit 34, the switch SW1 becomes non-conductive, and the DC / AC converter 31 does not perform the power conversion operation.

  At the time of a power failure, switch SW2 becomes non-conductive, and commercial AC power supply 70 and node N32 are electrically disconnected. In the power converter selected by the control unit 34 (P1 in this case), the DC / AC converter 31 converts the DC power from the battery 30 into AC power and supplies the AC power to the load 71. Therefore, the load 71 can be driven even during a power failure during the period in which the DC power is stored in the battery 30. Note that in the power conversion device that is not selected by the control unit 34 (in this case, P2 and P3), the switch SW1 remains non-conductive and the DC / AC converter 31 does not perform the power conversion operation.

  In the second embodiment, the number of power conversion devices necessary for driving the load 71 among the three power conversion devices P1 to P3 is selected, each selected power conversion device is operated, and each remaining power conversion device is operated. Stop the power converter. Therefore, compared with the case where all the power converters P1 to P3 are operated regardless of the load current, the loss generated in the power converters P1 to P3 can be reduced and the efficiency can be increased.

  Moreover, the power converter to be operated is changed at a predetermined cycle so that the operation times of the three power converters P1 to P3 are equal to each other. Therefore, the continuous operation time of each power converter can be shortened, and the failure of the power converter can be reduced. In addition, it is possible to quickly find a power converter that has failed during a stop.

[Embodiment 3]
FIG. 13 is a circuit block diagram showing the configuration of the frequency conversion system according to the third embodiment of the present invention, which is compared with FIG. Referring to FIG. 13, this frequency conversion system is different from the uninterruptible power supply system of FIG. 1 in that uninterruptible power supply devices U1 to U3 are replaced with frequency conversion devices P11 to P13, respectively. Each of frequency conversion devices P11 to P13 includes a converter 41 and an inverter 42.

  The input nodes of the three converters 41 are commonly connected to the node N1. Node N1 is connected to commercial AC power supply 70. Converter 41 converts commercial AC power from commercial AC power supply 70 into DC power. The inverter 42 converts the DC power supplied from the converter 41 into AC power having a frequency different from the commercial frequency. The output nodes of the three inverters 42 are commonly connected to the node N2. Node N2 is connected to load 71.

  The current sensor 4 detects a current flowing from the node N2 to the load 71, and gives a signal indicating the detected current value to the control unit 5. Based on the output signal of the current sensor 4, the control unit 5 obtains the number of frequency converters (for example, one) required to drive the load 71 and operates only that number of frequency converters (for example, P11). The remaining frequency converters (P12 and P13 in this case) are stopped.

  Moreover, the control part 5 changes the frequency converter operated to a predetermined period so that the operation time of several frequency converter P11-P13 may become equal. The rotation of the frequency converter to be operated is performed in the same manner as in the first embodiment. For example, the control unit 5 changes the frequency converter to be operated at a cycle of one day, and operates the three frequency converters P11 to P13 one by one in order. The control unit 5 is included in each control unit (not shown) of the frequency conversion devices P11 to P13, and the three frequency conversion devices P11 to P13 are controlled by the control unit 5 of one frequency conversion device. May be.

  In the third embodiment, the number of frequency conversion devices necessary for driving the load 71 among the three frequency conversion devices P11 to P13 is selected, and each of the selected frequency conversion devices is operated and each of the remaining frequency conversion devices is operated. Stop the frequency converter. Therefore, compared with the case where all the frequency converters P11 to P13 are operated regardless of the load current, the loss generated in the frequency converters U1 to U3 can be reduced and the efficiency can be increased.

  Moreover, the frequency converter to be operated is changed at a predetermined cycle so that the operation times of the three frequency converters P11 to P13 are equal to each other. Therefore, the continuous operation time of each frequency converter can be shortened, and the failure of the frequency converter can be reduced. Further, it is possible to quickly find a frequency converter that has failed during the stop.

[Embodiment 4]
FIG. 14 is a circuit block diagram showing a configuration of a power conversion device according to Embodiment 4 of the present invention, which is compared with FIG. Referring to FIG. 14, this power conversion device is different from the frequency conversion system of FIG. 13 in that frequency conversion devices P <b> 11 to P <b> 13 are each replaced with a converter 41.

  The input nodes of the three converters 41 are commonly connected to the node N1, and the output nodes of the three converters 41 are commonly connected to the node N2. Node N1 is connected to commercial AC power supply 70, and node N2 is connected to load 71. Converter 41 converts commercial AC power from commercial AC power supply 70 into DC power.

  The current sensor 4 detects a current flowing from the node N2 to the load 71, and gives a signal indicating the detected current value to the control unit 5. Based on the output signal of the current sensor 4, the control unit 5 obtains the number of converters 41 (for example, one unit) required to drive the load 71, operates only that number of converters 41, and the remaining converters 41. Stop.

  Moreover, the control part 5 changes the converter 41 to drive | operate with a predetermined period so that the operation time of the several converter 41 may become equal. The rotation of converter 41 to be operated is performed in the same manner as in the first embodiment. For example, the control unit 5 changes the converter 41 to be operated at a cycle of one day, and operates the three converters 41 one by one in order. The control unit 5 may be included in each control unit (not shown) of the converter 41, and the three converters 41 may be controlled by the control unit 5 of one converter 41.

  In the fourth embodiment, the number of converters 41 necessary for driving the load 71 among the three converters 41 is selected, the selected converters 41 are operated, and the remaining converters 41 are stopped. Therefore, compared with the case where all the converters 41 are operated regardless of the load current, the loss generated in the converters 41 can be reduced and the efficiency can be increased.

  Further, the converter 41 to be operated is changed at a predetermined cycle so that the operation times of the three converters 41 are equal to each other. Therefore, the continuous operation time of each converter 41 can be shortened, and the failure of the converter 41 can be reduced. Further, the converter 41 that has failed during the stop can be quickly found.

  FIG. 15 is a circuit block diagram showing a modification of the fourth embodiment, and is a diagram to be compared with FIG. Referring to FIG. 15, this modification is obtained by adding a battery 43 to the power conversion device of FIG. 14. The positive electrode of battery 43 is connected to node N2.

  When AC power is supplied from the commercial AC power supply 70, DC power generated by the converter 41 is stored in the battery 43 and supplied to the load 71. When the supply of AC power from the commercial AC power supply 70 is stopped (during a power failure), the converter 41 is stopped and the DC power stored in the battery 43 is supplied to the load 71. Therefore, the load 71 can be driven even during a power failure during a period in which the DC power is stored in the battery 43.

  Further, when the capacity (power consumption) of the load 71 is equal to the output of one converter 41, this power conversion device has a redundant function. That is, when only one converter 41 is in operation, even if the converter 41 breaks down, if the load 71 can be driven by the power of the battery 43 only during the period until the other one converter 41 is activated, There is no adverse effect on the load 71.

[Embodiment 5]
FIG. 16 is a circuit block diagram showing a configuration of a power conversion system according to Embodiment 5 of the present invention. In FIG. 16, this power conversion system includes a plurality (three in the figure) of power conversion devices P <b> 21 to P <b> 23, a current sensor 53, and a control unit 54. The power converters P21 to P23 are connected in parallel between the DC power source 72 and the load 71. DC power supply 72 is, for example, a solar battery panel, and generates DC power.

  Each of power conversion devices P21 to P23 includes a chopper 51 and an inverter 52. The input nodes of the three choppers 51 are commonly connected to the node N 1, and the node N 1 is connected to the DC power source 72. The chopper 51 boosts the output voltage of the DC power source 72 to a predetermined DC voltage and supplies it to the inverter 52. The inverter 52 converts the DC power supplied from the chopper 51 into AC power. The output nodes of the three inverters 52 are commonly connected to the node N2. Node N2 is connected to load 71.

  The current sensor 53 detects a current flowing from the DC power supply 72 to the node N1, and gives a signal indicating the detected current value to the control unit 54. Based on the output signal of the current sensor 53 and the output voltage of the DC power supply 72, the control unit 54 converts the DC power generated by the DC power supply 72 into AC power (for example, 1). The number of power conversion devices (for example, P21) is operated, and the remaining power conversion devices (in this case, P22 and P23) are stopped.

Moreover, the control part 54 changes the power converter device to drive | operate with a predetermined period so that the operation time of several power converter device P21-P23 may become equal. The rotation of the power converter to be operated is performed in the same manner as in the first embodiment. For example, the control part 54 changes the power converter device to drive | operate with a 1-day cycle, and makes the three power converter devices P21-P23 drive one by one in order. Incidentally, the control unit 54 previously be included in each of the controller of the power converter P21 to P23 (not shown), the three by one of the power conversion equipment of the control unit 54 of the power converter P21 to P23 You may control.

  In the fifth embodiment, the number of power conversion devices necessary for converting the DC power generated by the DC power source 72 among the three power conversion devices P21 to P23 into AC power is selected, and each of the selected power conversion devices is selected. The power converter is operated and the remaining power converters are stopped. Therefore, the loss generated in the power conversion device can be reduced and the efficiency can be increased as compared with the case where the entire power conversion device is operated regardless of the load current.

  Moreover, the power converter to be operated is changed at a predetermined cycle so that the operation times of the three power converters P21 to P23 are equal to each other. Therefore, the continuous operation time of each power converter can be shortened, and the failure of the power converter can be reduced. In addition, it is possible to quickly find a power converter that has failed during a stop.

  FIG. 17 is a circuit block diagram showing a modification of the fifth embodiment, which is compared with FIG. Referring to FIG. 17, this modified example is different from the fifth embodiment in that the output nodes of three choppers 51 and the output nodes of three inverters 52 are connected to each other, and control unit 55 is added. It is a point that has been.

  The control unit 55 has the same configuration as the control unit 54. The control unit 54 controls the operation / stop of the three choppers 51, and the control unit 55 controls the operation / stop of the three inverters 52. That is, the control unit 54 selects and selects the number of choppers 51 necessary for boosting the DC voltage generated by the DC power supply 72 to a predetermined DC voltage according to the output current and output voltage of the DC power supply 72. The choppers 51 to be operated are operated, the remaining choppers 51 are stopped, and the choppers 51 to be operated are changed at a predetermined cycle so that the operation times of the three choppers 51 are equal to each other. In addition, when one chopper 51 fails, the control unit 54 controls the operation / stop of the remaining two choppers 51 so that the operation times of the two choppers 51 are equal to each other. The chopper 51 is changed at a predetermined cycle.

  Similarly, the control unit 55 selects and selects the number of inverters 52 required to convert the DC power generated by the DC power source 72 into AC power according to the output current and output voltage of the DC power source 72. Each inverter 52 is operated, the remaining inverters 52 are stopped, and the inverters 52 to be operated are changed at a predetermined cycle so that the operation times of the three inverters 52 are equal to each other. Further, when one inverter 52 fails, the control unit 55 controls the operation / stop of the remaining two inverters 52 so that the operation times of the two inverters 52 are equal to each other. The inverter 52 is changed at a predetermined cycle. Even in this modified example, the same effect as in the fifth embodiment can be obtained.

  FIG. 18 is a circuit block diagram showing another modification of the fifth embodiment, which is compared with FIG. Referring to FIG. 18, the modification differs from the fifth embodiment in that three choppers 51 are removed and the input nodes of three inverters 52 are commonly connected to node N1.

  Based on the output signal of the current sensor 53 and the output voltage of the DC power source 72, the control unit 54 converts the DC power generated by the DC power source 72 into AC power (for example, one inverter 52). ), Only the number of inverters 52 are operated, and the remaining inverters 52 are stopped.

  Moreover, the control part 54 changes the inverter 52 to drive | operate with a predetermined period so that the driving | running time of the some inverter 52 may become equal. The rotation of the inverter 52 to be operated is performed in the same manner as in the first embodiment. For example, the control unit 54 changes the inverter 52 to be operated at a daily cycle, and causes the three inverters 52 to be operated one by one in order. The control unit 54 may be included in a control unit (not shown) of each inverter 52, and the three inverters 52 may be controlled by the control unit 54 of one inverter 52. Even in this modified example, the same effect as in the fifth embodiment can be obtained.

[Embodiment 6]
FIG. 19 is a circuit block diagram showing a configuration of a power conversion device according to Embodiment 6 of the present invention, and is compared with FIG. Referring to FIG. 19, this power conversion device is different from the power conversion device in FIG. 18 in that three inverters 52 are replaced with three DC / DC converters 60.

  The input nodes of the three DC / DC converters 60 are commonly connected to the node N1, and the output nodes of the three DC / DC converters 60 are commonly connected to the node N2. Node N1 is connected to DC power supply 72, and node N2 is connected to load 71. The DC / DC converter 60 converts the output voltage of the DC power source 72 into a predetermined DC voltage and supplies it to the load 71.

  Based on the output signal of the current sensor 53 and the output voltage of the DC power source 72, the control unit 54 converts the output voltage of the DC power source 72 into a predetermined DC voltage (for example, the number of DC / DC converters 60 required). 1 unit), only that number of DC / DC converters 60 are operated, and the remaining DC / DC converters 60 are stopped.

  Moreover, the control part 54 changes the DC / DC converter 60 to drive | operate with a predetermined period so that the operation time of the some DC / DC converter 60 may become equal. The rotation of the DC / DC converter 60 to be operated is performed in the same manner as in the first embodiment. For example, the control unit 54 changes the DC / DC converter 60 to be operated at a cycle of one day, and operates the three DC / DC converters 60 one by one in order. The control unit 54 is included in the control unit (not shown) of each DC / DC converter 60, and the three DC / DC converters 60 are controlled by the control unit 54 of one DC / DC converter 60. May be.

  In the sixth embodiment, the number of DC / DC converters 60 necessary for converting the first DC power generated by the DC power source 72 of the three DC / DC converters 60 into the second DC power. The selected DC / DC converter 60 is operated, and the remaining DC / DC converters 60 are stopped. Therefore, compared with the case where all the DC / DC converters 60 are operated regardless of the load current, the loss generated in the DC / DC converters 60 can be reduced and the efficiency can be increased.

  Further, the DC / DC converters 60 to be operated are changed at a predetermined cycle so that the operation times of the three DC / DC converters 60 are equal to each other. Therefore, the continuous operation time of each DC / DC converter 60 can be shortened, and the failure of the DC / DC converter 60 can be reduced. Further, the DC / DC converter 60 that has failed during the stop can be quickly found.

  FIG. 20 is a circuit block diagram showing a modified example of the sixth embodiment, which is compared with FIG. Referring to FIG. 20, this modification is obtained by adding a battery 61 to the power conversion device of FIG. The positive electrode of battery 61 is connected to node N2.

When DC power is supplied from the DC power supply 72, DC power generated by the DC / DC converter 60 is stored in the battery 61 and supplied to the load 71. When the supply of DC power from the DC power supply 72 is stopped, the DC / DC converter 60 is stopped and the DC power stored in the battery 61 is supplied to the load 71. Therefore, during the period in which the DC power is stored in the battery 61, the load 71 can be driven even when the supply of DC power from the DC power source 72 is stopped.
Further, when the capacity (power consumption) of the load 71 is equal to the output of one DC / DC converter 60, this power conversion device has a redundant function. That is, when only one DC / DC converter 60 is in operation, even if the DC / DC converter 60 fails, the battery 61 is used only for a period until the other DC / DC converter 60 is activated. If the load 71 can be driven with this power, the load 71 is not adversely affected.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  U1-U3 uninterruptible power supply, 1,41 converter, 2,30,43,61 battery, 3,42,52 inverter, 4,32,53 current sensor, 5,20,33,34,54,55 controller 11, 12 comparison circuit, 13 operation number determination unit, 14 timer, 15 storage unit, 16 failure detection unit, 17 operation command unit, 21 addition unit, 22 bidirectional chopper, P1-P3, P21-P23 power converter, 31 DC / AC converter, SW1, SW2 switch, P11 to P13 frequency converter, 51 chopper, 60 DC / DC converter, 70 commercial AC power supply, 71 load, 72 DC power supply.

Claims (20)

Connected in parallel between the power supply and load, and each of which a plurality of power conversion equipment and supplies by converting the first power to be supplied the power or al the second power to the load,
Select a power conversion device of the number necessary for converting the first power of the plurality of power conversion equipment to the second power, each remaining causes operate the respective power conversion device selected A control unit for stopping the power converter,
Wherein the control unit, as operating time of the plurality of power conversion equipment are equal to each other, changing at a period defined a power conversion device for driving previously, the power conversion system. The controller is
Number necessary for converting said plurality of power conversion devices in the failure of the power conversion equipment excluded from selection, the first power from a plurality of normal power conversion device to the second power Select the power converter
The power conversion system according to claim 1 , wherein the power conversion devices to be operated are changed at a predetermined cycle so that the operation times of the plurality of normal power conversion devices are equal to each other. The number of power conversion devices necessary for converting the first power into the second power is the minimum number of power conversion devices required for converting the first power into the second power. The power conversion system according to claim 1 , comprising: The power conversion system according to claim 3 , wherein the number of power conversion devices necessary for converting the first power into the second power further includes a spare power conversion device. The control unit includes a number of power conversion devices necessary for converting the first power into the second power based on at least one of the first power and the second power. The power conversion system according to claim 1 , wherein the power conversion system is selected. The second power is the power required for driving the load,
Wherein, as the power converter of the number necessary for converting the first power to the second power, to select a power converter of the number required for driving the load, wherein Item 4. The power conversion system according to Item 1 . The first power is the power generated by the power supply,
The control unit may need to convert the first power as a power converter of the number required for converting the second power, the power generated by the power supply to the second power The power conversion system according to claim 1 , wherein a number of power conversion devices are selected. The power supply is a commercial AC power supply,
The first power is a commercial power first AC power;
The second power is a second AC power of the commercial frequency;
Each of the plurality of power conversion equipment is an uninterruptible power supply,
Wherein, as the power converter of the number required for converting the first AC power to the second AC power, select the uninterruptible power supply number required for driving the load And
Each uninterruptible power supply
A converter for converting the first AC power supplied to said commercial AC power supply or we into DC power,
And a inverter to be supplied to the load by converting the DC power supplied to said converter or found in the second AC power,
If the said commercial AC power supply or we first AC power is supplied, the DC power generated by the converter is stored in the energy storage equipment is supplied to the inverter, the commercial AC power If the source or al supply of the first AC power is stopped, the operation of the converter is said DC power into said energy storage systems placed et the inverter with stops being supplied, in claim 1 The described power conversion system. Each uninterruptible power supply further, when the commercial AC power supply or al the first AC power is supplied, and supplies the DC power generated by the converter to the power storage equipment, the If the supply of the commercial AC power supply or al the first AC power is stopped, includes an interactive chopper for supplying the DC power to the energy storage system placed et the inverter, the power according to claim 8 Conversion system. The power supply is a commercial AC power supply,
The first power is a commercial power first AC power;
The second power is second AC power having a frequency different from the commercial frequency,
Wherein, as the power converter of the number required for converting the first AC power to the second AC power, and select the power converter of the number required for driving the load ,
Each power converter is
A converter for converting the first AC power supplied to said commercial AC power supply or we into DC power,
By converting the DC power supplied to said converter or found in the second AC power and an inverter for supplying the load, the power conversion system according to claim 1. The power supply is a DC power supply,
The first power is DC power;
The second power is AC power;
Wherein, as the power converter of the number necessary for converting the first power to the second power, required to convert the DC power generated by the DC power source to the AC power Select a number of power converters,
Each power converter converts the DC power supplied to said DC power source or al the AC power including inverter to be supplied to the load, the power conversion system according to claim 1. The power supply is a DC power supply,
The first power is DC power;
The second power is AC power;
Wherein, as the power converter of the number necessary for converting the first power to the second power, required to convert the DC power generated by the DC power source to the AC power Select a number of power converters,
Each power converter is
A chopper for converting the predetermined DC voltage an output voltage of the DC power supply,
It converts the output voltage of the chopper into an AC voltage and a inverter to be supplied to the load, the power conversion system according to claim 1. It said input node of the inverter of the plurality of power converting devices are connected to each other, the power conversion system according to claim 12. The power supply is a DC power supply,
The first power is a first DC power;
The second power is a second DC power;
Wherein, the first as a power conversion device number required to convert the power to the second power, the said first direct current power generated by the DC power a second DC power Select the required number of power conversion devices to convert to
Each power converter includes a converter to be supplied to the load is converted into a predetermined DC voltage an output voltage of the DC power supply, power conversion system according to claim 1. Further comprising a connected power storage equipment to the output node of the converter,
Wherein when the DC power source or al the first DC power is supplied, the generated by the converter second DC power stored in the power storage equipment is supplied to the load, wherein when the supply of the first DC power of the DC power supply or we are stopped, the said second DC power energy storage systems placed et the to the load is supplied, the power converter according to claim 14 system. A plurality of the uninterruptible power supply connected in parallel between the commercial AC power supply and load,
Each uninterruptible power supply
A converter for converting the first AC power supplied to said commercial AC power supply or we into DC power,
And a inverter for converting the DC power into second AC power,
Further, to select the inverter of the number required for driving the load of the plurality of inverters, a control unit for stopping the rest of each inverter causes operate each inverter selected,
Wherein the control unit is configured as the operating times of a plurality of inverter are equal to each other, to change the period defined the inverter to be operated in advance, uninterruptible power supply system. A plurality of uninterruptible power supplies connected in parallel between the commercial AC power supply and load,
Wherein the plurality of provided in common to the uninterruptible power supply, and a power storage equipment for storing the DC power,
Each uninterruptible power supply
A converter for converting the first AC power supplied to said commercial AC power supply or we into DC power,
The converter Tama other includes a inverter for converting DC power supplied et placed the energy storage system to the second AC power,
Wherein the power storage equipment will store the DC power generated by each of the converters of the plurality of uninterruptible power supply,
Further, to select the converter of number necessary for driving the load of the plurality of converter, a control unit for stopping the rest of the converter causes operate each converter selected,
Wherein the control unit is configured as the operating times of a plurality of converter are equal to each other, changing at a period defined a converter to be operated in advance, uninterruptible power supply system. And a plurality of uninterruptible power supply,
Wherein the plurality of provided in common to the uninterruptible power supply, and a power storage equipment for storing the DC power,
Wherein the plurality of input nodes of the uninterruptible power supply are both connected to a commercial AC power, their output nodes are respectively connected to a plurality of load,
Each uninterruptible power supply
A converter for converting the first AC power supplied to said commercial AC power supply or we into DC power,
The converter Tama other includes a inverter for converting the DC power supplied et placed the energy storage system to the second AC power,
Wherein the power storage equipment will store the DC power generated by each of the converters of the plurality of uninterruptible power supply,
Further, to select the converter of number necessary for driving the plurality of loads of the plurality of converter, a control unit for stopping the rest of the converter causes operate each converter selected ,
Wherein the control unit is configured as the operating times of a plurality of converter are equal to each other, changing at a period defined a converter to be operated in advance, uninterruptible power supply system. Each uninterruptible power supply further, when the commercial AC power supply or al the first AC power is supplied, giving the DC power generated by the converter to the power storage equipment, the commercial when the supply of the first AC power of the AC power supply or we are stopped, saw including a bidirectional chopper providing said DC power of the power storage equipment to the inverter,
The inverter, the converter Tama other converts the DC power supplied et al or the bidirectional chopper to the second AC power,
Wherein the power storage equipment is stored the bidirectional chopper said DC power path or we supplied for each of the plurality of uninterruptible power supply,
The control unit may further remains with select bidirectional chopper of number necessary for driving the plurality of loads of the plurality of bi-directional chopper, thereby driving the respective bidirectional chopper selected each bidirectional chopper was stopped, the as operating time of a plurality of bidirectional chopper become equal to each other, to change the period defined bidirectional chopper be operated in advance, free of claim 18, Power outage system. Meanwhile terminal receives the AC power of the commercial AC power supply or al, is the other terminal connected to the load, normal to the commercial AC power supply or et AC power is supplied to conduct AC of the commercial AC power supply or al power failure the supply of power is stopped and the switch becomes non-conductive,
It said switch connected in parallel to the other terminal of the switch, each said normal is supplied to the AC power supplied through the commercial AC power supply or al the switch into a DC power energy storage equipment, the power failure is a plurality of power conversion equipment to be supplied to the load by converting DC to AC power of the power storage equipment,
Select a power conversion device of the number required for driving the load of the plurality of power conversion equipment, a control unit for stopping each of the remaining power converter causes operate the respective power conversion device selected And
The said control part is an uninterruptible power supply system which changes the power converter device to drive | operate with a predetermined period so that the operation time of these power converter devices may become mutually equal.

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