JPS63217934A - Non-interrupting electric source - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device for backing up commercial power during a power outage, and particularly to an uninterruptible power supply suitable for computers that operate on commercial power.

[Conventional technology]

A conventional uninterruptible power supply of this type uses an inverter device operated by a battery, for example as described in Japanese Patent Laid-Open No. 59-47939, and when the commercial AC power supply is in a normal state, the inverter device The battery was charged through the freewheeling diode in the main switch circuit, and the inverter supplied AC power in the event of a power outage.

Incidentally, in such an uninterruptible power supply using an inverter device, the input side DC voltage of the inverter device requires a voltage higher than the peak value of the AC side output.

Therefore, in the conventional device described above, a battery whose rated voltage is higher than the peak value of the commercial AC power source is used as the battery to be connected to the DC side input of the inverter device, and the DC output that can be obtained from the commercial power source under normal conditions is used. The voltage is boosted to enable charging.

[Problem that the invention seeks to solve]

The above conventional technology requires a battery whose output voltage is higher than the AC peak value of the commercial power supply, and therefore requires a battery with a large number of cells, making it difficult to reduce costs.

SUMMARY OF THE INVENTION An object of the present invention is to provide an uninterruptible power supply that can sufficiently address the problems of the prior art described above, operate with a battery with a small number of cells, and sufficiently reduce costs.

[Means for Solving the Problems] The above object is to provide a DC boosting means that boosts the battery's voltage to provide a DC voltage for the inverter circuit, and a DC booster that steps down the inverter's DC voltage to provide a DC voltage for the inverter circuit between the inverter circuit and the battery. This is achieved by providing a parallel circuit of photovoltaic switching means.

[For production]

The switching means charges the battery by stepping down the DC voltage obtained by rectifying the AC power with a freewheeling diode in the inverter circuit when the AC power is normal, and the DC boosting means steps up the battery voltage during a power outage. Since this DC voltage is converted into an AC voltage by an inverter circuit, the battery voltage can be lower than the peak value of the AC power supply voltage.

〔Example〕

Hereinafter, the uninterruptible power supply according to the present invention will be explained in detail with reference to an illustrated embodiment. Fig. 1 shows an embodiment of the present invention, and 1 indicates a commercial current.

2 is the load, 3 is the inverter circuit, and 4 is the battery.

5 is an AC switch, 6 is a step-up chopper circuit, 7 is a switching circuit, and 8 is a smoothing capacitor 7.

A commercial power supply 1 is a 100V commercial AC power supply, and serves to supply operating power to a load 2, such as a computer, which is extremely averse to power outages.

The inverter circuit 3 is a single-phase inverter consisting of four transistors 30 to 33, free-wheeling diodes 34 to 37, a smoothing glue handle 38, and a capacitor 39. By controlling the on/off of 33, K functions to generate a single-phase AC output of 100V from the DC voltage E.

The battery 4 is a secondary battery such as a lead-acid battery or a nickel-cadmium storage battery, and has a rated voltage that can be charged by direct current obtained by rectifying 100 V alternating current from the commercial power supply 1.
For example, it has an output voltage e of 80V, and functions as a DC power source for the inverter circuit 3 during a power outage.

The AC switch 5 is composed of a thyristor connected in antiparallel, and functions to disconnect the commercial power supply l in the event of a power outage, and is configured to be controlled by a control circuit (not shown).

The boost chopper circuit 6 includes a glue handle 6 for generating back electromotive force.
0. Switching transistor 61° freewheeling diode 62. In addition, the transistor 61 is configured with a rectifying diode 63 and is controlled on and off at a predetermined period by a control circuit (not shown), thereby operating as a DC boosting means, and generates a DC voltage E higher than the voltage e of the battery 4. functions to charge the capacitor 8.

The switching circuit 7 is constituted by a transistor 70, and is controlled on/off at a predetermined duty ratio by a control circuit (not shown) to step down the voltage E and output it as the voltage e17. Works as a buck chopper.

Next, the operation of this embodiment as a whole will be explained separately for normal times and power outages.

A. During normal operation (when there is no power outage) At this time, the specified AC power is being supplied from the commercial power supply 1, so the control circuit (not shown) closes the AC switch 5 and closes the inverter circuit 3 and boosts the voltage. The chopper circuit 6 is kept in an immobile state, that is, the transistors 30 to 33 and the transistor 61 are all kept in an off state.

Therefore, an alternating current voltage of voltage V is applied to the load 2 from the commercial power source 1, and the load 2 is maintained in a state where current power can be supplied as desired.

On the other hand, the AC voltage V from the commercial power supply 1 is also applied to the AC output side of the inverter circuit 3. At this time, transistors 30 to 33, which are switching elements of this inverter circuit 3, are all kept off, but freewheeling diodes 34 to 37 are connected in antiparallel to these, and AC voltage V A single-phase bridge rectifier circuit is configured for this.

Therefore, at this time, the inverter circuit 3 has the AC voltage V applied to its AC side output from the commercial power supply 1, so that this AC voltage V is rectified by the freewheeling diodes 34 to 37, and the DC voltage is applied to the DC side input of the inverter circuit 3. Generates E.

Therefore, when the commercial power supply 1 is maintained normally, a control circuit (not shown) controls the AC switch 5 to close, and at the same time supplies a pulse to the transistor 70 of the switching circuit 7 to turn the transistor 70 into a predetermined state. It is controlled to turn on and off at a predetermined duty ratio at a cycle of .

As a result, the switching circuit 7 operates as a step-down chopper, converting the DC voltage E into a lower DC voltage e and supplying it to the battery 4.

Therefore, under normal conditions, power is supplied from the commercial power source 1 to the negative fI2, and charging current is also supplied to the battery 4, so that the battery 4 is always maintained in a fully photoelectric state.

B. At the time of a power outage Next, when a power outage state occurs and the voltage from the commercial power supply 1 disappears, a control circuit (not shown) detects this power outage state, and as a result, the step-up chopper circuit 6
A pulse is supplied to the transistor 61, and this transistor 61 is turned on and off at a predetermined cycle under a predetermined duty ratio, and a predetermined back electromotive force is generated in the reactor 60 and added to the voltage e of the battery 4. This added voltage is applied to the capacitor 8 via the diode 63.
It becomes DC voltage E and is charged.

Note that at this time, the transistor 7 of the switching circuit 7
Needless to say, for 0, the supply of pulses is stopped in advance and controlled to be in the OFF state.

Meanwhile, in parallel, the above-mentioned control circuit supplies pulses at predetermined phases to each of the transistors 30 to 33 of the inverter circuit 3, thereby generating an AC output of a predetermined voltage at a predetermined frequency. control so that it can operate as an inverter.

As a result, the AC side output of the inverter circuit 3 has the same voltage V at the same frequency as when it was supplied from the commercial power supply 1.
AC voltage will be obtained and supplied to load 2,
Even during a power outage, the load 2 continues to operate under stable AC power, and functions as an uninterruptible power supply.

According to this embodiment, the voltage e of the battery 4 is input to the DC side input of the inverter circuit 3 by the step-up chopper circuit 6.
Since the voltage e of the battery 4 is boosted and supplied as a DC voltage E, the voltage e of the battery 4 is equal to the voltage i required for the operation of the inverter circuit 3.
The a-current voltage E may be much lower than the current voltage E. Therefore, for example, an uninterruptible power supply with an AC output of 100 V can be obtained using a battery of about 80 V, and the cost increase due to an increase in the number of cells can be significantly suppressed. can.

Note that the AC switch 5 is controlled to be open during this outage, and when the power is restored the next time (when the power outage is restored and the commercial power supply 1 is
It goes without saying that preparations should be made for when it becomes possible to supply energy from the

FIG. 2 shows another embodiment of the present invention, in which the transistor 61 and freewheeling diode 62 of the boost chopper circuit 6 in the embodiment of FIG. Transistors 30 to 33 and freewheeling diode 3 forming the arm
4 to 37 and all (noting that they have the same configuration, these are configured as general-purpose modules 101, 102, and 103 whose cost is reduced by generalization. Therefore, according to this embodiment, Further, cost reduction can be achieved.In this embodiment, a semiconductor switching element is used as the AC switch 5, and therefore, the practicality is high.

FIG. 3 shows still another embodiment of the present invention, in which the diodes 62 and 63 of the boost chopper circuit 6 are replaced with transistors 62' and 63', respectively, and the transistors 6] and 63' are turned on and off in a complementary manner. As a result, the operation as a boost chipper circuit 6 is obtained, and the transistors 70 and 62
By complementarily turning on and off ', it operates as a step-down chopper.

According to the example shown in FIG. 3, if an abnormality occurs in the circuit, the battery 4 can be disconnected from the commercial power supply by turning off both the transistors 63' and 70. , the circuit can be sufficiently protected.

In addition, in the above-mentioned examples, the inverter circuit 3
, a boost chopper circuit 6, and a switch path.

Although a transistor is used as the switching element of the switching circuit 7, it goes without saying that any switching element having a self-extinguishing function such as a MOSFET may be used instead.

In addition, in the embodiment described in 1.H, a double-cut type switch is used as the AC switch 5, but a switch that cuts only one wire may be used.

〔Effect of the invention〕

According to the present invention, since it is not necessary to use a battery with a voltage higher than the peak value of AC voltage, it is possible to sufficiently reduce costs by using a battery with a small number of cells.

[Brief explanation of the drawing]

Figure 1 shows non-stop operation according to the present invention! FIGS. 2 and 3 are circuit diagrams showing one embodiment of the power supply device, and FIGS. 2 and 3 are circuit diagrams showing other embodiments of the present invention, respectively. 1...Commercial power supply, 2...Load, 3...
...Inverter circuit, 4...Battery, 5
... AC switch, 6 ... Boost chopper circuit, 7 ... Switching agent Patent attorney Kenji Takeshi Department (outside 14 Word 4 Battery 5 Z piercing type ÷

Claims (1)

[Claims] 1. By providing an inverter device with a secondary battery connected to the DC side input, and connecting the AC side output of this inverter device in parallel to a commercial AC power supply, AC load power can be reduced during normal conditions. In the uninterruptible power supply device, the supply of charging power to the secondary battery is performed from the commercial AC power source, and the inverter device is configured to supply AC load power during a power outage. and switching means for bypassing the DC boosting means, the inverter device and the secondary battery are connected via the DC boosting device, and the input of the DC boosting device is connected to the DC side input of the inverter device. and an uninterruptible power supply configured such that the outputs are respectively connected to the terminals of the secondary battery. 2. Claim 1, characterized in that the DC boosting means is a boosting chopper circuit, and the switching means is composed of a transistor connected in antiparallel to a rectifying diode of the boosting chopper circuit. Uninterruptible power system.