JPH0779577A - Booster type uninterruptible power supply - Google Patents

Abstract

PURPOSE:To use a low-voltage battery to set up an uninterruptible power supply. CONSTITUTION:Diode 46 and 30 are connected in parallel between serially connected switching elements 22 and 29, and capacitors 28 and 32 are connected in series between the elements 22 and 29. Switching elements 34 and 36 are connected in series between the capacitors 28 and 32, and a serial circuit of a switching means 76 which opens when a power failes and a reactor 26, and another serial circuit of a switching means 78 which short-circuits when a power failes and a battery 60, are connected between the connecting point of the element 22 with the element 29 and one terminal of an AC power source. The connecting point between the capacitors 28 and 32 is connected to the other terminal of the AC power source. A switching means 72 which turns on when a power failes is connected to the connecting point between the reactor 26 and switching means 76 and the connecting point between the element 29 and capacitor 32. The element 22 is periodically turned on and off when the AC power source is at one polarity and the element 29 is periodically turned on and off when the AC power source is at the other polarity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a step-up type uninterruptible power supply.

[0002]

2. Description of the Related Art Conventionally, there is a booster type uninterruptible power supply apparatus as shown in FIG. 2, for example. This uninterruptible power supply has input terminals 10, 1 connected to a commercial AC power supply.
2 and the input terminal 10 is a positive half-wave whose potential is higher than that of the input terminal 12, the capacitor 18 is charged through the high frequency noise removal coil 14 and the current limiting resistor 16. For example, when the voltage of the commercial AC power supply has an effective value of 100 V, 14
Charge to 0V. When the charging is completed, the triac 20 connected in parallel to the current limiting resistor 16 receives a gate signal from a control circuit (not shown) and becomes conductive, and the current limiting resistor 16
Short circuit.

During the positive half-wave period, a gate signal having a frequency of, for example, 15 to 20 kHz is supplied to a switching element 22 such as an IGBT from a control circuit (not shown), and the switching element 22 responds to the gate signal. Repeat on and off. When the switching element 22 is on, it flows to the capacitor 28 through the AC power supply, the one input terminal 10, the high frequency noise removing coil 14, the triac 20, the reactor 26, and the switching element 22, and the capacitor 28 is reversely charged or discharged. To do.

When the switching element 22 is off,
A voltage is generated in the reactor 26 in the direction indicated by the arrow, and a current from the reactor 26 is connected to the switching element 22 in series with the switching element 29 such as an IGBT.
Then, the current flows to the capacitor 32 connected in series with the capacitor 28 via the diode 30 connected in anti-parallel, and further to the high frequency noise removal coil 14 and the other input terminal 12. At this time, the capacitor 32 is charged to the polarity shown in FIG. 2, and its maximum voltage is normally boosted to a voltage equal to the sum of the AC power supply voltage and the back electromotive force of the reactor 26.
V boosted.

On the other hand, in the case of a negative half wave in which the potential of the terminal 10 is lower than the potential of the terminal 12, the input terminal 10 is passed through the input terminal 12, the high frequency noise removing coil 14, the capacitor 18, the triac 20, and the high frequency noise removing coil 14. A current flows and the capacitor 18 is charged. Also, input terminal 1
2, high frequency noise removal coil 14, capacitor 28, diode 46 connected in antiparallel to switching element 22, reactor 26, triac 20, high frequency noise removal coil 14, input terminal 10 and current flow and capacitor 28 is charged. .

During this negative half-wave period, the switching element 29, like the switching element 22, is repeatedly turned on and off by a gate signal having a frequency of, for example, 15 to 20 kHz supplied from a control circuit (not shown). When the switching element 29 is on, current flows from the AC power supply, the other input terminal 12, the high frequency noise removing coil 14 to the capacitor 32, the switching element 29, and the reactor 26, and the capacitor 32 is reversely charged or discharged.

When the switching element 29 is off,
A voltage in the direction opposite to the arrow is generated in the reactor 26, and a current flows from the reactor 26 to the reactor 26 via the triac 20, the high frequency noise removal coil 14, the AC power supply, the high frequency noise removal coil 14, the capacitor 28, and the antiparallel diode 46. 2, the capacitor 28 is charged to the polarity shown in FIG. 2, and its maximum voltage is boosted to the sum of the AC power supply voltage and the back electromotive force of the reactor 26, usually 200V.

Then, switching elements 34, 3 such as IGBTs connected in series between the capacitors 32, 28.
Among them, the switching element 34 is turned on for a certain period by a gate signal from a control circuit (not shown). As a result, the electric charge of the capacitor 32 flows to the capacitor 32 through the switching element 34, the output reactor 38, the high frequency noise removing coil 40, the output terminal 42, a load (not shown), the output terminal 44, and the high frequency noise removing coil 40, and the load. AC output is supplied to.

When the switching element 36 is turned on for a certain period of time, the high-frequency noise removing coil 40, the output terminal 44, the load (not shown), the output terminal 4 are discharged from the capacitor 28.
2, high frequency noise removal coil 40, output reactor 3
8. A current flows through the capacitor 28 via the switching element 36, and an AC output is supplied to the load.

Incidentally, 48 and 50 are switching elements 3.
4 and 36 are diodes connected in anti-parallel.

By the way, in the power supply device of FIG. 2, the switching element 52 and the storage battery 54 are provided between the capacitors 28 and 32.
Series circuit is connected, and the connection point of these two is
It is connected to the connection point between the capacitor 32 and the switching element 34 via the diode 56. The switching element 52 is turned on by a gate signal from a control circuit (not shown) while the commercial AC power is being supplied, and charges the storage battery 54.

When the commercial AC power source is out of power, the voltage of the storage battery 54 is applied across the switching elements 34 and 36 via the diode 56, and the switching elements 34 and 36 are switched in the same manner as described above. The element 34 is turned on for a predetermined period of time corresponding to the positive half wave,
The switching element 36 is repeatedly turned on for a predetermined period of time corresponding to a negative half-wave, and even if there is a power failure, an AC output is supplied to the load as before the power failure.

Reference numeral 58 is a high frequency noise removing coil 1.
The switching element 22, 29, 34, 36 and the capacitor 2 described above are connected by a triac connected between 4 and 40.
It is turned on during maintenance and inspection of the booster type inverter circuit composed of 8 and 32 and supplies commercial AC power to the load through the high frequency noise elimination coils 14 and 40.

[0014]

However, in the uninterruptible power supply device as described above, since the voltages of the capacitors 28 and 32 are 400V, respectively, the storage battery 54 capable of generating a voltage of 400V or more is required. There is a problem that the device must be used and the device becomes large.

[0015]

In order to solve the above problems, the present invention has first and second switching elements connected in series, and these first and second switching elements are provided. , The first and second diodes are connected in antiparallel with the same directionality. First and second capacitors are connected in series between the first and second switching elements. An inverter is connected between the first and second capacitors. Between the connection point of the first and second switching elements and one terminal of the AC power supply, the first
A series circuit including an opening / closing means and a reactor, a storage battery, and a second
A series circuit with the opening / closing means is connected in parallel. A third switching means that is turned on at least during a power failure is connected between a connection point between the reactor and the first switching means and a connection point between the second switching element and the second capacitor. The first switching element is periodically turned on and off when the AC power supply has one polarity, and the second switching element is turned on and off when the AC power supply has the other polarity and when the AC power supply has a power failure. , Is turned on and off periodically. When the AC power source has a power failure, the first opening / closing means is opened and the second opening means is short-circuited.

[0016]

According to the present invention, when the AC power source has one polarity,
The first switching element is repeatedly turned on and off, and in the on state, current flows from the AC power supply to the reactor. When the first switching element is off, a counter electromotive force is generated in the reactor, a current flows from the reactor to the second capacitor and the AC power supply, and the voltage of the second capacitor is the counter electromotive force of the AC power supply voltage and the reactor. The voltage is the sum of the electric power. That is, the voltage of the second capacitor is a voltage boosted higher than the voltage of the AC power supply.

When the AC power supply has the other polarity, the second switching element repeatedly turns on and off. In the ON state, when the AC power supply has a positive polarity, a current flows in the opposite direction, and a current flows in this reactor. An electric current flows.
When the second switching element is off, a counter electromotive force is generated in the first reactor, the counter electromotive force and the AC power supply voltage are applied to the first capacitor, and the voltage of the first capacitor is the AC power supply. It is boosted more than the voltage.

When the AC power source fails, the first opening / closing means is opened, the second opening / closing means is short-circuited, and the second switching element is repeatedly turned on / off. When the second opening / closing means is short-circuited, a current flows from the storage battery to the reactor. Then, when the second switching element is turned off, a counter electromotive force is generated in the reactor. This voltage and the voltage of the storage battery are added and applied between the first and second capacitors. That is, the voltage of the storage battery is boosted, and the first and second
Applied across the capacitors.

[0019]

1 shows an embodiment of an uninterruptible power supply according to the present invention. The same parts as those of the conventional one shown in FIG. 2 are designated by the same reference numerals, and the description thereof will be omitted.

In this embodiment, the series circuit of the reactor 26 and the first opening / closing means 76 and the series circuit of the storage battery 60 and the second opening / closing means 78 are connected to the AC power source and the first and second switching elements 22 and 29. It is connected to the connection point. Further, a diode 72 is connected between the connection point between the reactor 26 and the first switching means and the connection point between the second switching element 29 and the second capacitor 32.

In this embodiment, the first opening / closing means 76 is turned on when the commercial AC power source is applying a voltage to the input terminals 10 and 12, in the same manner as described with reference to FIG. The AC output is supplied to the load.

When a power failure occurs in this state, a detector (not shown) detects this power failure state, the first opening / closing means 76 is opened via the control circuit (not shown), and the second opening / closing hand is short-circuited.

A control circuit (not shown) simultaneously supplies a gate signal having a frequency of 15 kHz to 20 kHz to the switching element 29 to turn on the switching element 29.
Turn off. When the commercial AC power source is supplying power, the gate signal supplied to the switching element 29 is
It occurred only during the period corresponding to the negative polarity, but in the power failure state, it occurs continuously until the power failure is restored.

When the switching element 29 is short-circuited,
Current is supplied from the storage battery 60 to the reactor 26 via the storage battery 60, the reactor 26, the diode 72, the switching element 29, and the second opening / closing means 78. And
When the switching element 29 is off, the reactor 2
6, a counter electromotive force is generated in the direction indicated by the arrow in FIG. 1, and a current flows through the diode 72, the capacitors 32 and 28, the diode 46, the switching means 78, and the storage battery 60, and
A voltage obtained by adding the voltage of the reactor 26 and the voltage of the storage battery 60, that is, a voltage obtained by boosting the voltage of the storage battery 60 is applied between 2 and 28. The voltage between the capacitors 32 and 28 is
ON / OFF control is performed by the switching elements 34 and 36, that is, inverter control is performed and the load is supplied to the load.

In the above embodiment, the switching element 2
IGBTs were used for 2, 29, 34, and 36, but in addition to FE
T and bipolar transistors can also be used. Further, the first opening / closing means and the second opening / closing means may be not only relays but also electronic switches. Further, instead of the diode 72, a relay or an electronic switch which is short-circuited at the time of power failure may be used. The storage battery is charged from a charger (not shown) when the AC power supply is normal.

[0026]

As described above, according to the present invention, the series circuit of the opening / closing means and the reactor which is opened at the time of a power failure between the connection point of the first and second switching and one terminal of the AC power supply, A series circuit of an opening / closing means and a storage battery that short-circuits at the time of a power failure is provided, and a connection point between the reactor and the first opening / closing means and a second
Since the third switching means which is turned on at the time of a power failure is provided at the connection point between the switching element and the second capacitor, the voltage of the storage battery is boosted by turning on and off the second switching element, and It can be applied between the second capacitors. Therefore, as the storage battery, it is possible to use an AC power source that generates a voltage lower than the voltage applied to the first or second capacitor when the power is supplied.
This uninterruptible power supply can be downsized.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an embodiment of an uninterruptible power supply according to the present invention.

FIG. 2 is a circuit diagram of a conventional uninterruptible power supply device.

[Explanation of symbols]

 18 (Input) Capacitor 22 (First) Switching Element 26 Reactor 28 (First) Capacitor 29 (Second) Switching Element 30 Diode 32 (Second) Capacitor 34 Switching Element (Inverter) 36 Switching Element (Inverter) ) 46 diode 60 storage battery 72 (third) opening / closing means 76 (first) opening / closing means 78 (second) opening / closing means

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Atsushi Makita 2-14-3 Awaji, Higashiyodogawa-ku, Osaka-shi, Osaka Sansha Electric Co., Ltd.

Claims (1)

[Claims] 1. A first and a second switching element connected in series, a first and a second diode connected to the first and the second switching element in antiparallel with the same directionality, and First and second capacitors connected in series between the first and second switching elements, an inverter connected between the first and second capacitors, and a connection point of the first and second switching elements And a series circuit of a first opening / closing means and a reactor which are connected between one terminal of an AC power supply and open at the time of power failure, a series circuit of a second opening / closing means and a storage battery which are short-circuited at the time of power failure, the reactor and the above The third switching means is provided between the connection point of the first switching means and the connection point of the second switching element and the second capacitor and is turned on at least at the time of power failure. ,Up Note that the AC power supply is periodically turned on / off when the polarity is one, and the second switching element is periodically turned on / off when the AC power is the other polarity and when the AC power is out of power. Step-up type uninterruptible power supply.