JPH0635637Y2 - Uninterruptible power system - Google Patents

Description

[Detailed Description of the Invention] A. Field of Industrial Application The present invention relates to an uninterruptible power supply using a CVCF of a floating charging type, and in particular, a plurality of CVCFs are configured in parallel and have a common battery. Regarding a power failure power supply.

CVCF (Constant Voltage Constant Freguency Power Su
pply) is known as an AC constant voltage constant frequency power supply device that keeps the output voltage and frequency constant regardless of AC input fluctuations and output loads, and uses a rotary type and thyristor inverter that uses a motor generator. It is classified as a static type. In general, the stationary type occupies an overwhelming share, and is often used as an uninterruptible power supply in combination with a battery.

B. Outline of the Invention The present invention is an uninterruptible power supply device in which a plurality of CVCFs are configured in parallel and have a common battery, with a diode and a fuse connected in series and a thyristor connected in antiparallel to them. By configuring the DC switch on the connection line between each CVCF forward converter and the battery and by connecting the anode side of the thyristor to the battery, even if an accident occurs in the DC circuit part Disclosed is a technique that can maintain the independence of a DC circuit portion and improve system reliability.

C. Conventional Technology CVCF, which is generally known as a floating charging technology,
A commercial AC power supply is once converted into direct current, and then it is converted back into alternating current to realize a stabilized power supply.In general, a thyristor converter or the like capable of controlling DC voltage is provided in the forward conversion unit. It is used.

FIG. 2 is a circuit diagram showing a basic example of such a floating charging type CVCF. In the figure, CVCF is a converter 1 as a forward converter between an AC input and a load output,
The inverter 2 as an inverse conversion unit is connected in series, and a line to the battery 3 is connected to an intermediate point between them to supply power to the inverter 2 and at the same time charge the battery 3. In the figure, 4 is an output filter.

D. Problems to be solved by the invention CVCF has two devices to improve the reliability of the system.
In some cases, more than one unit may be arranged in parallel to provide redundancy. Even in this case, two or more batteries are rarely prepared, and in most cases, only the batteries are common.

FIG. 3 is a circuit diagram showing an example of such a CVCF parallel configuration. As shown in FIG. 3, the first CVCF is the converter 1a.
And the inverter 2a are connected in series, and the second CVCF is configured independently by connecting the converter 1b and the inverter 2b in series, but as is apparent in the figure, the battery 3 is common. Therefore, the DC circuit portion including the battery becomes a common portion as a system, although the devices have a parallel configuration. Therefore, if an accident such as a ground fault occurs in one of the DC circuit parts, a current may flow from the output side of the other converter and the system may be down, so that it can be said that the configuration lacks reliability.

The present invention was devised in view of these problems, and it is possible to maintain the independence of the DC circuit parts of a plurality of CVCFs even when an accident occurs in the DC circuit part, and improve the system reliability. It is intended to provide an uninterruptible power supply.

E. Means for solving the problem In the present invention, the means for solving the above-mentioned problem is to arrange a plurality of CVCFs that connect a DC voltage controllable forward converter to an inverter and a battery in parallel. In a floating charging type uninterruptible power supply device that is installed and connected to a common battery, a DC switch consisting of a diode and a fuse connected in series and a thyristor connected in anti-parallel to them is connected to the CVCF forward conversion unit. And an anode side of the thyristor connected to the battery on the connection line between the battery and the battery to provide an uninterruptible power supply device.

F. Function In the present invention, when multiple CVCFs are configured in parallel and the battery is shared, the deterioration of reliability due to the common DC circuit part is avoided and an accident occurs in the DC circuit part of one CVCF. However, the other CVCF continues to operate without any effect and continues to supply power to the load.

G. Embodiment Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a circuit diagram showing an example of an uninterruptible power supply device embodying the present invention. In the figure, the uninterruptible power supply is 2
The two CVCFs are arranged in parallel with the AC input and the load output, and each CVCF has a converter 1a, 1
b, the inverters 2a and 2b as the inverse conversion units, and the output filters 4a and 4b are connected in series, and the line to the battery 3 is connected to the intermediate point between the converter and the inverter,
It is configured to supply electric power to both 2a, 2b and the battery 3. The battery 3 is common to the two CVCFs, and this configuration is almost the same as the configuration of FIG. 3, but the DC switch 5a and the DC switch 5a are connected on the connection line between the forward conversion unit of each CVCF and the battery 3.
5b is installed.

With this configuration, normally, the reversely converted alternating current is output as a load, and the battery 3 is charged with the forward converted direct current. When an accident occurs in the alternating current input, the thyristors 53a, 5b of the direct current switches 5a, 5b, 53b is turned on, the electric power of the battery 3 is replaced with the output of the converters 1a, 1b, and the electric power is inversely converted by the inverters 2a, 2b to output an alternating current as a load, thereby realizing an uninterruptible power supply.

DC switches 5a and 5b are diodes 51a and 51b and fuses.
52a, 52b and thyristor 53 connected in antiparallel to them
It is composed of a and 53b. The thyristors 53a and 53b are naturally commutated, the anode side thereof is connected to the battery 3, and the diodes 51a and 51b and the fuses 52a and 52b are connected in series. Since the thyristors 53a and 53b are normally off and do not pass current in both directions, and the diodes 51a and 51b do not pass current in the opposite direction, for example, a DC circuit between the converter 1a and the inverter 2a of one CVCF. When a ground fault or the like occurs in a part, the current from the converter 1b side of the other CVCF is blocked by the DC switch 5a and does not flow in.

In addition, in the above example, the thyristor 53 of the DC switch 5a
If a occurs when the power is on from the battery 3 when a is turned on, the current from the converter 1b flows through the fuse 52b and the diode 51b of the DC switch 5b, but when an excessive current flows. Fuse 52b
As a result, the current flows out and is cut off, the DC circuit does not become common, and the reliability of the system in parallel is maintained.

Note that the fuses 52a and 52b need only be smaller than the device capacity because they need only be inserted in the diode side so that only the charging current is taken into consideration.

Thus, in the present invention, in the event of a DC circuit accident, the CVCF
Since the independence of the DC circuit section for each can be maintained, the reliability of the system is improved.

H. Effect of the Invention As described above, according to the present invention, even when an accident occurs in the DC circuit part, the independence of the DC circuit part for each of the plurality of CVCFs can be maintained and system reliability is improved. A power failure power supply can be provided.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an embodiment of the present invention, FIG. 2 is a circuit diagram of a general floating charging type CVCF, and FIG. 3 is a circuit diagram of a conventional example. 1,1a, 1b …… Converter converter, 2,2a, 2b …… Inverter inverter, 3 …… Battery, 4,4a, 4b …… Output filter, 5a, 5b …… DC switch, 51a , 51b ... Diode, 52a, 52b ... Fuse, 53a, 53b ... Thyristor.

Claims (1)

[Scope of utility model registration request] 1. A plurality of CVCFs for connecting a DC voltage controllable forward conversion unit to an inverter and a battery are arranged in parallel,
In a floating charging uninterruptible power supply connected to a common battery, a DC switch consisting of a diode and a fuse connected in series and a thyristor connected in anti-parallel to them is connected to the forward conversion unit of each CVCF and the battery. An uninterruptible power supply device characterized in that an anode side of a thyristor is provided on a connection circuit so as to be connected to a battery and DC power of the battery is supplied to an inverter when the thyristor is turned on.