JP3898355B2 - Uninterruptible power system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
In this invention, while receiving commercial power, the commercial power is supplied to the load and charged to the storage battery with a charger. When a power failure occurs, the power of the storage battery is boosted with a booster circuit, and the boosted output is converted to AC power with an inverter. And an uninterruptible power supply for supplying the AC power to the load.
[0002]
[Prior art]
FIG. 5 shows a conventional uninterruptible power supply. Commercial power from the commercial power supply 11 is supplied to the load 13 via the output switching relay 12. Moreover, the commercial power is charging the storage battery 15 by the charger 14.
When a power failure occurs, the power failure detection control unit 16 detects the power failure, switches the output switching relay 12 to the inverter 17 side, and activates the booster circuit 18 and the inverter 17. The power of 36 to 60 V from the storage battery 15 is boosted to, for example, 165 V by the booster circuit 18, the DC power of 165 V is converted into AC power of 100 V by the inverter 17, and the AC power is supplied to the load 13 through the output switching relay 12. Supplied.
[0003]
[Problems to be solved by the invention]
When a power failure occurs, the switching relay 12 is switched in about 4 to 8 milliseconds. On the other hand, the voltage of the storage battery 15 is about 36 to 60 V, and the voltage on the output side of the booster circuit 18 is about the same as the output voltage of the storage battery 15 in a state where commercial power is supplied to the load 13. In order to supply the AC voltage of 100V to the load 13 by starting the booster circuit 18 and the inverter 17 due to a power failure, the output voltage of the booster circuit 18 needs to be about 165V. In other words, the output voltage of the booster circuit 18 needs to be increased from 36 to 60 V to 165 V, but as shown by the broken line in FIG. For this reason, in the past, a power failure occurred, and when the output of the inverter 17 was supplied to the load 13, there was a problem that AC power of 100 V or less was supplied to the load 13 as indicated by the broken line in FIG. 6B. It was.
[0004]
[Means for Solving the Problems]
According to the present invention, there is provided means for holding the output side of the booster circuit at a voltage higher than the voltage of the storage battery during commercial power reception.
With this configuration, when a power failure occurs, the output voltage of the booster circuit becomes a predetermined voltage in a shorter time than in the prior art, and when the power failure occurs, the required inverter output voltage is obtained from the beginning of switching.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a first embodiment of the present invention, in which parts corresponding to those in FIG. In the charger 14, the commercial power is rectified by the rectifier 20 and charged in the capacitor 21. The charged power is converted into a predetermined DC voltage by the transformer 22, the switching transistor 23, the rectifier diode 24, and the capacitor 25, and the DC The storage battery 15 is charged with voltage. Switching control of the switching transistor 23 is performed by the charge control unit 26.
[0006]
In the booster circuit 18, the output of the storage battery 15 is charged into a capacitor 28, a series circuit of an inductor 29 and a switching transistor 31 is connected in parallel with the capacitor 28, and a capacitor 33 is connected in parallel with the switching transistor 31 through a rectifier diode 32. The transistor 31 is switching-controlled by the drive circuit 34. The power of the capacitor 28 is boosted and the capacitor 33 is charged. The booster circuit 18 is a DC-DC converter.
[0007]
Power between both ends of the capacitor 33 of the booster circuit 18 is supplied to the inverter 17. Each switching element of the inverter 17 is controlled by a drive circuit 35. The commercial power is branched and supplied to the power failure detection circuit 16a. When a power failure is detected, the detected output is supplied to the control unit 16b and also supplied to the output switching relay 12, and the switching is controlled. The control unit 16b issues a start command to the drive circuits 34 and 35. Although not shown in the figure, there is provided control means for holding the output voltage of the booster circuit 18 and the output voltage of the inverter 17 at a constant value during a power failure.
[0008]
In this embodiment, a tertiary winding 41 is wound around the secondary winding of the transformer 22 of the charger 14, and the winding end of the tertiary winding 41 passes through a rectifying diode 42 and is a connection point between the diode 32 and the capacitor 33. Connected to. The auxiliary winding circuit is configured by the tertiary winding 41 of the transformer 22 and the rectifying diode 42.
With this configuration, while receiving commercial power, the capacitor 33 is charged through the diode 42, and the capacitor 33 is held at an output voltage of the storage battery 15, that is, for example, 130V higher than 30-60V.
[0009]
When a power failure occurs in this state, the output of the booster circuit 18 starts to rise from 130V, and thus reaches the standard value 165V in a short time as shown by the solid line in FIG. 6A. Therefore, when the load 13 is switched to the inverter 17 side, 100V AC power is supplied to the load 13 as shown by a solid line in FIG. 6B. Note that there is no possibility that the load of the capacitor 33 flows to the charger 14 side by the diode 42 during the boosting operation of the boosting circuit 18. In this embodiment, the tertiary winding 41 of the auxiliary booster circuit is directly connected to the secondary winding of the transformer 22. However, the tertiary winding (auxiliary winding) 41 not directly connected to the secondary winding is used. May be used.
[0010]
In the second embodiment of the present invention, the output voltage of the booster circuit 18 is branched and applied to the intermittent control unit 43 through the voltage divider circuit 44 as shown in FIG. In the intermittent control unit 43, when the output voltage of the booster circuit 18 becomes, for example, 130V (first reference voltage value) or less during a non-power failure, this is detected and the drive circuit 34 is activated to operate the booster circuit 18, When the output voltage of the booster circuit 18 exceeds a standard value, which is 165 V (second reference voltage value) in the above example, this is detected, the operation of the drive circuit 34 is stopped, and the operation of the booster circuit 18 is stopped.
[0011]
With this configuration, the output of the booster circuit 18 is held at 130 to 165 V while receiving commercial power. Therefore, when a power failure occurs, the output voltage of the booster circuit 18 becomes a standard value in a shorter time than before, and 100V AC power is supplied to the load 13 from the beginning when the load 13 is switched to the inverter 17 side. .
FIG. 3 shows a third embodiment of the present invention. In this figure, the intermittent control unit 43 and the voltage dividing circuit 44 in FIG. 2 are omitted, and a periodic control unit 45 is provided. That is, if the time required for the output reduction (165 V → 130 V) of the booster circuit 18 and the time when the output recovers (130 V → 165 V) by starting the booster circuit 18 are known, these are set as the pause time and the start time. In the third embodiment, the booster circuit 18 is periodically driven by the periodic controller 45 having the timer circuit.
[0012]
It is also possible to combine and use the first embodiment and the second embodiment or the third embodiment. The former example is the same as the portion corresponding to FIGS. 1 and 2 in FIG. Reference numerals are attached and description is omitted.
[0013]
【The invention's effect】
As described above, according to the present invention, while receiving commercial power, the output side of the booster circuit 18 is relatively close to the voltage higher than the voltage of the storage battery 15, that is, the standard value of the output voltage of the booster circuit 18, for example, 165V. Because of the voltage, during a short period of time when the power failure occurs and the load 13 is switched to the inverter 17 side, the output voltage of the booster circuit 18 becomes the standard value, and 100V AC power is switched from the inverter 17 to the load 13. Supplied from the beginning.
[Brief description of the drawings]
FIG. 1 is a diagram showing a first embodiment of the present invention.
FIG. 2 is a diagram showing a second embodiment of the present invention.
FIG. 3 is a diagram showing a third embodiment of the present invention.
FIG. 4 is a view showing still another embodiment of the present invention.
FIG. 5 is a block diagram showing an outline of a conventional uninterruptible power supply.
6 is a diagram showing the output voltage of the booster circuit 18 and the voltage supplied to the load 13 when a power failure occurs after receiving commercial power. FIG.

Claims (3)

While receiving commercial power, supply the commercial power to the load and charge the storage battery with the charger.
When a power failure occurs, the power of the storage battery is boosted by a booster circuit, the boosted output is converted to AC power by an inverter, and the AC power is supplied to the load in the uninterruptible power supply,
Means is provided for holding the output side of the booster circuit at a voltage higher than the voltage of the storage battery during commercial power reception .
It said means for holding the high voltage output side of the booster circuit, uninterruptible power supply characterized that you have been configured by the auxiliary booster circuit using a transformer of the charger. While receiving commercial power, supply the commercial power to the load and charge the storage battery with the charger.
When a power failure occurs, the power of the storage battery is boosted by a booster circuit, the boosted output is converted to AC power by an inverter, and the AC power is supplied to the load in the uninterruptible power supply,
Means is provided for holding the output side of the booster circuit at a voltage higher than the voltage of the storage battery during commercial power reception .
The means for holding the output side of the booster circuit at a high voltage includes a means for detecting the output voltage of the booster circuit, and activates the drive circuit of the booster circuit when the detected voltage is equal to or lower than a first reference voltage value. the uninterruptible power supply detection voltage, wherein more Rukoto and means for stopping the driving of the first reference voltage becomes higher than the higher second reference voltage when the drive circuit. While receiving commercial power, supply the commercial power to the load and charge the storage battery with the charger.
When a power failure occurs, the power of the storage battery is boosted by a booster circuit, the boosted output is converted to AC power by an inverter, and the AC power is supplied to the load in the uninterruptible power supply,
Means is provided for holding the output side of the booster circuit at a voltage higher than the voltage of the storage battery during commercial power reception .
It said means for holding the high voltage output side of the booster circuit, uninterruptible power supply, wherein means der Rukoto for operating the booster circuit periodically.

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