JPH05211730A - Uninterruptible power supply - Google Patents

Abstract

PURPOSE:To simplify constitution and to prevent the application of overvoltage to a charger at the time of the recovery of power. CONSTITUTION:The AC power of a commercial power supply 13 is supplied to a load 18 and half-wave rectified through diodes 51, 38 to charge a capacitor, and the voltage of the capacitor is rectified into a suitable voltage by a charger 53 having an oscillation circuit built-in to charge a storage battery 25. At the time of service interruption, a relay 19 is energized, a booster chopper 26 and inverter 17 are actuated and the power of the storage battery 25 is converted into AC power and supplied to the load 18. The positive output side of the charger 53 is separated from the storage battery 25, the output of the storage battery 25 is inputted to the charger 53 through diode 52, and operating supply voltage mutually separated in DC from the charger 53 is formed and applied to each of a controller 41 and drive circuits 43-46.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention supplies AC power from a commercial power source to a load, charges a storage battery, and when the commercial power source fails, boosts the voltage of the storage battery and then converts it into AC power by an inverter. The present invention relates to an uninterruptible power supply device that supplies a load.

[0002]

2. Description of the Related Art FIG. 3 shows a conventional uninterruptible power supply. A commercial power supply 13 is connected to the pair of input terminals 11 and 12, and the input terminals 11 and 12 are connected to the pair of output terminals 16 and 17 through conductors 14 and 15, respectively. The load 18 is connected between the output terminals. Normally closed relay contact 19a on lead wire 14
Has been inserted. A bridge-type full-wave rectifier circuit 21 is connected between the input terminals 11 and 12, a capacitor 22 is connected between both ends on the output side of the rectifier circuit 21, and a charger 23 is also provided.
The input side of is connected. The output side of the charger 23 is connected to both ends of the storage battery 25 through the backflow prevention diode 24. The boost chopper 26 is connected to both ends of the storage battery 25,
The output side of the boost chopper 26 is connected to the input side of the inverter 27.

In the inverter 27, transistors 31 to 34 as switching elements are bridge-connected, and diodes 35 to 38 in opposite directions are connected in parallel with the transistors 31 to 34, respectively. The low-pass filter 39 is connected to the output side of the inverter 27, one end of the output side of the filter 39 is connected to the output terminal 16 through the normally open relay contact 19b, and the other end is connected to the output terminal 17. A control unit 41 is connected to the input terminals 11 and 12, and a relay 19 controlled by the control unit 41 and having relay contacts 19a and 19b is connected. Auxiliary power source 4 at both ends of the storage battery 25
2 is connected, and an operating power supply isolated from the auxiliary power supply 42 is isolated from the direct current for the control unit 41, the drive circuits 43 to 46 for the transistors 31 to 34, and the like.

The AC power from the commercial power supply 13 is supplied to the load 18, the AC power is rectified by the rectifier circuit 21, and the rectified output charges the storage battery 25 through the charger 23. When the commercial power supply 13 fails, this is detected by the control unit 41, and the control unit 41 energizes the relay 19 and operates the step-up chopper 26 and the inverter 27. Therefore, the voltage of the storage battery 25 is boosted, the boosted voltage is converted into AC power by the inverter 27, and the load 18
Is supplied to.

As shown in FIG. 4, the full-wave rectification circuit 21 is omitted and the conductor 14 is connected to one end of the capacitor 22 through the diode 47 to charge the storage battery 25 and half-wave rectify the commercial AC power. There are also things to do.

[0006]

In the conventional apparatus shown in FIG. 3, the negative side input end 23a and the output end 23b of the charger 23 must be galvanically isolated from each other.
When the power is restored during operation of the transistor 7, the commercial power supply 13 is short-circuited through the transistor 34 and the full-wave rectifier circuit 21 when the transistor 34 is on, and the transistor 34 is destroyed.

The charger 23 converts the electric power of the capacitor 22 into an appropriate AC voltage by the output transformer of the automatic oscillation circuit so as to correspond to the charging voltage for the storage battery 25, and then converts it into DC, that is, a DC-DC converter. Has been done. The auxiliary power source 42 also receives the power of the storage battery 25 as an input, and after converting it into an AC voltage corresponding to the power source voltage of each section by the output transformer of the automatic oscillation circuit, converts it to DC.

As described above, the charger 23 and the auxiliary power source 42 are similar in construction, but even if the charger 23 is also used as the auxiliary power source 42, the charger 23 receives the power from the storage battery 25 at the time of a power failure and supplies the power to the charger 23. In order to operate as a circuit, it is necessary to connect the charger 23 and the storage battery 25. If this is the case, as described above, when power is restored during operation of the inverter, the commercial power supply is short-circuited. Had a charger 23 and an auxiliary power supply 42 separately.

In the conventional device shown in FIG. 4, the negative side of the charger 23, the negative side of the auxiliary power supply 42 and the negative side of the storage battery 25 can be connected in common, but while the inverter 27 is operating, When the power is restored and the commercial AC power V _C is near the positive peak when the transistor 33 is turned on,
The higher voltage obtained by subtracting the on-voltage of the transistor 33 from the sum of V _C and the output voltage V _B of the boost chopper 26 is the charger 2.
3 and the charger 23 may be destroyed.

An object of the present invention is to use both a charger and an auxiliary power source to simplify the structure, and moreover, an uninterruptible power supply device in which an excessive voltage is not applied to the charger even when the power is restored during the operation of the inverter. To provide.

[0011]

According to the present invention, one output terminal is connected through the first diode to one end on the input side of the charger, and at this connection point, one end of the storage battery is connected.
It is connected to this through a second diode in the forward direction, and is provided with means for disconnecting the output side of the charger from the storage battery in the event of a power failure, and the charger is configured so that the operating power supply for the drive circuit of the inverter is galvanically isolated. Has been done.

[0012]

FIG. 1 shows an embodiment of the present invention, in which parts corresponding to those in FIG. 4 are designated by the same reference numerals. According to the present invention, the output terminal 16 is connected to the positive side input end of the charger 53 through the first diode 51, the anode of the first diode 51 is on the output terminal 16 side, and the positive side output end of the boost chopper 26 is It is connected to the positive side input end of the charger 53 through this and the second diode 52 in the forward direction, and is further connected in series between the positive side output end of the charger 53 and the positive side of the storage battery 25 in a normally closed relay contact of the relay 19. 19c is inserted. The negative sides of the charger 53, the storage battery 25, and the step-up chopper 26 are commonly connected.
Although not specifically shown in the drawing, the charger 53 is provided with operating power supplies that are galvanically isolated from each other for the drive circuits 43 to 46 and the control unit 41.

In this configuration, the first
The capacitor 22 is charged by the half-wave rectification through the diode 51 and the diode 38, and the storage battery 25 is charged by the charger 53. When a power failure occurs and this is detected, the relay 19 is energized and the boost chopper 2
6. The inverter 27 is operated, the relay contact 19c is turned off, the positive side output end of the charger 53 is separated from the storage battery 25, and the power of the storage battery 25 is supplied to the input side of the charger 53 through the second diode 52 and charged. The device 53 functions as an auxiliary power source, and the drive circuits 43 to 46, the control unit 41, and the like are activated.

Even when power is restored during operation of the inverter 27, the first diode 51 is disconnected from the commercial power source 13 because the relay contact 19a is off, and the first diode 51 is connected to the charger 53 at the positive peak of the output of the commercial power source 13. There is no risk of high voltage being applied. FIG. 2 shows a specific example of the charger 53. Transistor 5
4 and an oscillating transformer 55 that positively feeds back its collector output to the base form an automatic oscillation circuit. Output extracting coils 56, 57, 58 and 59 are coupled to the transformer 55, and a rectifying circuit 61 is connected to both ends of the coil 56.
A rectifier circuit 62 is connected between the center tap and one end of the coil 56, and rectifier circuits 63, 64 and 65 are connected to both ends of the coils 57, 58 and 59, respectively. The output of the rectifier circuit 61 is used for charging the storage battery 25, the output of the rectifier circuit 63 is given to the control unit 41 as the operating power supply voltage, and the output of the rectifying circuit 62 is given as the operating power supply voltage of the drive circuits 44, 46. The outputs of the rectifier circuits 64 and 65 are given as the operating power supply voltages of the drive circuits 43 and 45, respectively. In this way, the driving of the transistors 31 to 34 can be performed with direct current insulation.

When the output voltage of the rectifier circuit 61 becomes higher than a predetermined value, the light emitting diode 66 emits light, the phototransistor 67 becomes conductive, and the transistor 68 is easily turned on. When the transistor 68 is turned on, the transistor 54 is turned on.
Of the rectifier circuit 6
The output of 1 is held at a predetermined voltage. In the above, an electronic switch may be used instead of the relay contact.

[0016]

As described above, according to the present invention, the charger can also be used as an auxiliary power source for generating the internal power source, and the number of parts can be reduced accordingly, and the cost can be reduced. Further, even if the power is restored during the operation of the inverter, the overvoltage is not applied to the charger, the charger is not damaged, and the reliability is improved.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a connection diagram showing a specific example of a charger 53 in FIG.

FIG. 3 is a configuration diagram showing a conventional uninterruptible power supply device.

FIG. 4 is a configuration diagram showing another conventional uninterruptible power supply device.

Claims (1)

[Claims] 1. An AC power from a commercial power source is supplied to a load, a storage battery is charged through a charger, and when a blackout of the commercial power source is detected, the voltage of the storage battery is boosted by a chopper circuit, and the boosted voltage is obtained. In an uninterruptible power supply that converts the generated voltage to AC by an inverter and supplies it to the load, an output terminal for one end of the load is connected to one end of a capacitor connected to the input side of the charger through a first diode. , One end of the storage battery is connected to the connection point through the second diode in the forward direction at the connection point, and means for disconnecting the output side of the charger and the storage battery during a power failure is provided, An uninterruptible power supply characterized in that the operating power supply for the drive circuit of the inverter is configured to be DC isolated.