JPS5843147A - No-break power 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 The present invention relates to an uninterruptible power supply equipped with a constant voltage, constant frequency power supply and a standby power supply circuit, and particularly to an uninterruptible power W* system that contributes to energy saving.

FIG. 1 is a four-dimensional diagram showing an example of a conventional uninterruptible power supply system.

In Figure 1, 1 is a constant voltage constant frequency power supply (hereinafter simply KCV)
CF), 2 is a backup power supply circuit, 3 is a power supply switching circuit,
4 is a load, 5 is a rectifier, and 6 is a storage battery.

8 indicates an inverter transformer.

In the normal operation method, CVCFl is always operated and power is supplied to load 4 via power supply switching circuit-3.
As for the operation of the CP1, the AC rectifier 5 converts the alternating current into direct current KL, the inverter transforms the direct current into AC IIIK, and the inverter transformer 8 converts the voltage into the voltage required by the load 4 to supply power. In this state, if the CVCFIO human power source is out of power, the standby storage battery 61C (inverter 7) is enabled to operate uninterruptedly, and the load 4 is able to be supplied with uninterrupted power.

On the other hand, in the event of an accident or maintenance of the CVCFI, power from the backup power supply circuit 2 can be supplied to the load 4 through the power supply switching circuit 3. There are two types of power supply switching circuits 3, a mechanical type switching device and a semiconductor type. In the case of the semiconductor type, it is also possible to switch the power supply switching circuit 3 without momentary interruption during the above switching.

゛Now, the above operation method is the most common method adopted in most uninterruptible power supply systems, but it cannot be called an energy-saving type of operation method.The reason is that the amount of heat generated by operating the CVCFI and the This is because there is electricity used by the air conditioning equipment necessary to process this.

The amount of heat generated from the cvcpt is caused by the operation of the rectifier 5, inverter 7, and inverter transformer 8, and is approximately 10 to 20% of the rated output power. Naturally, this heat will be accumulated as power loss from you. In order to eliminate these energy losses, it is conceivable to use the backup power supply circuit 2 to supply power to the load 4 via the power supply switching circuit 3. In the case of ζO, the following two points need to be considered compared to the above-mentioned method of constantly feeding power from cvcy1.

(1) Is the power supply of standby power supply circuit 2 of good quality? (2)
In the event of a power outage in the backup power supply circuit 2, start the Inno (-Tough),
What is the allowable instantaneous interruption time for the power supply to the load 4 via the switching device 3?As for the quality of the power supply of the trenchless standby power supply circuit 2, if the power is supplied by commercial power supply, it is representative of CVCFI. The power supply situation in the vicinity has improved to the extent that electronic computers, communications equipment, broadcasting equipment, instrumentation equipment, etc., which are major loads, can be operated without any problems. However, in places where the power situation is poor, it is necessary to consider constantly supplying power using CVCFIk as described above.

Also, if there is a power outage and power is supplied from a private power generator, etc., the quality of the power source is poorer than that of commercial power sources, so CV
It is preferable to supply power from cii't.

Next, let's consider the second consideration item, the allowable instantaneous interruption time VC. When there is a power outage in the backup power supply circuit 2, a start command is transmitted to the inverter by a signal from a power outage detection circuit (not shown). In this case, when the inverter 7 was started instantaneously, the excitation inrush current of the inverter transformer 8 caused the inverter 7 ti' to fail in commutation due to an overcurrent, or the protection circuit was activated, making it impossible to start.

As a means to eliminate this drawback, there is an inverter starting method called a soft start method.

FIG. 2 shows a pair of inverter transformers 8 and 1. In the figure, ■ is the output voltage of the inverter, T is the time, and i is the output of the inverter. It is an electric current.

FIG. 3 is an explanatory diagram of the soft start method.

In the figure, v, T', and i are the same as those in FIG.

Since the output voltage of the inverter is gradually increased, the protection circuit does not operate and it starts normally. In this case, the engine starts normally, but it takes k from a fraction of a second to several seconds until power is supplied to the load. ? : The instantaneous power outage time of , can be said to be fatal for the load (electronic computer part) #IC. This method is not used except for some special loads.

An object of the present invention is to compensate for the above-mentioned drawbacks and provide an energy-saving uninterruptible power supply, and one embodiment of the present invention will be described below with reference to the drawings.

FIG. 4 shows an embodiment of the present invention, and in FIG. 4, the same numbers as in FIG. 1 indicate the same elements as in FIG. 1.

The preliminary power supply circuit 2 through the Hiro power supply switching circuit 3 to the negative @4,
Power is supplied at all times. If a power outage occurs in the backup power supply circuit 2 at this time, the gate pull of the inverter 7 is released by the power failure detector 9, and the synchronous control device 10 is used to maintain the same phase relationship as before the power outage in the backup power supply circuit 2, and the inverter 7 is activated. It is something that moves people. l In this case, when the inverter transformer 8 is not energized, an overcurrent flows and the inverter 7 cannot be started, as explained earlier.Therefore, the above-mentioned drawback is eliminated by energizing the inverter transformer 8 in advance via the start compensation device 11. I can do it.

That is, since the inverter transformer 8 is always energized close to the rated voltage by the starting compensation device 11, if a voltage in the same direction and phase as this energized magnetic field is supplied to the inverter transformer 8 from the inverter. , the inverter 7 will not experience overcurrent or commutation failure.

In parallel with the above operation, the power supply switching circuit 3 has a function of switching from the preliminary power supply circuit 2 to the CVCfi'x at high speed.

In the series of operations described above, the reliability of power supply to the load 4 is influenced by the switching time difference of the semiconductor products, but recent advances in semiconductor products have been remarkable, and it can be said that this switching time is practically uninterrupted.

FIG. 5 illustrates a gate block method for the inverter 7 of FIG. 4. In FIG. 5, 12 is a semiconductor element, 1:%a gene block switch, and 14 is a gate control device. The gate control device 14 generates a signal having the same phase relationship as the preliminary power supply circuit 2 based on the signal from the synchronous control device 10 shown in FIG. At the same time as a power outage occurs, the signal from the power outage detector 9 causes the gate block switch 1 in Figure S to be activated.
3 supplies the gate signal 14 to the semiconductor element 12 and outputs an AC output when it is closed. Note that although this explanation is for a single phase, the principle is the same even if a multi-phase inverter is used.

FIG. 6 shows the state of each part in a graph 97 based on the above explanation. It is assumed that a power outage occurs at the center point in Figure 6. 1 indicates the state of the backup power supply circuit, B indicates the state of the inverter that starts at the same time as a power outage, and C indicates that the power supply switching circuit has switched to the cvcy side. As a result, D shows a state in which power is supplied to the load without momentary interruption even if there is a power outage.

No. 7- is a modification of the present invention. In Figure 7, the fourth
The same number 011 as in the figure indicates the same thing as in FIG. 4. 7th
In the figure, 7 indicates a small inverter. The small inverter is operated in the same phase as the standby power supply circuit 2 by the synchronous control device 10, and its output is connected to the inverter transformer 8. This inverter transformer 8 is always excited to prevent overcurrent and commutation failure when the inverter 7 is started during a power outage.

Figure 8! This is a modification of the present invention. In Figure 8, the fourth
The same numbers as in the figures indicate the same parts as in FIG. 4. In FIG. 1, 15 is a three-winding inverter transformer. Instead of the starting compensation device shown in Fig. 4, if the voltage of the preliminary power supply circuit 2 is applied to the tertiary winding of the three-winding inverter transformer 15 shown in Fig. 8 and energized, the inverter will start during a power outage. This prevents overcurrent and commutation failure if

As explained above, according to the present invention, a power supply system has a power supply system of two circuits: a CVCF that is always on standby and a CVCF that always supplies power to the load side without going through the CVCF such as a commercial power supply. By combining an inverter that instantaneously starts in the event of a power outage with an inverter transformer that is excited in the same phase as a power source that does not go through a CVCF, such as a commercial power source, energy-saving operation can supply power to the load without momentary interruption. method can be realized.

[Brief explanation of the drawing]

Figure 1 is a configuration diagram of a conventional uninterruptible power supply, Figure 2 is a voltage and current waveform diagram of an inverter that starts instantly, and Figure 3 is a voltage and current waveform diagram of a soft-start inverter. Fig. 4 is a configuration diagram showing an embodiment of the present invention, Fig. 5 is a diagram showing the connection of a gate block switch when the input and output terminals in Fig. 4 are single-phase inverters, and Fig. 6 is a diagram showing the connection of the gate block switch according to the present invention. 7 and 8 are configuration diagrams showing other different embodiments of the present invention. 1...CVCP 2...Auxiliary power supply circuit 3.
...Power switching circuit 4...Load 5,...Rectifier
6...Storage battery 7...Inverter] Person...Small inverter 8...Inverter transformer 9
... Power outage detector 10 ... Synchronous control device 11.
...Start compensation device 12...Semiconductor element 13.
... Gate block switch 1m ... Gate control device 15 ... Three-winding inverter transformer () 317) Agent Patent attorney Kensuke Chika (and 1 other person) No. IML / No. 211 Collection 31g T 7
Figure 4 Figure 5 /, Ma Figure 6 D BYPASs, CV (:F Figure 7 Figure 8

Claims (1)

[Claims] A switching circuit selects either one of a constant voltage, constant frequency power source and a commercial power source having an inverter that converts direct current supplied from a storage battery into alternating current, and energizes the load with the selected next power source. In the uninterruptible power supply, the synchronous control device controls the ignition circuit of the inverter so that the output voltage of the inverter is in phase with the voltage of the commercial AC power supply; a gate block switch that blocks gate pulses supplied to the inverter; an excitation device that excites a transformer provided on the output side of the inverter with a voltage that is in phase with the voltage of the commercial power source; A power outage detector is provided to detect an abnormal drop in power or a power outage, and when the commercial power supply is normal, the load is energized by the commercial power supply, and when the power outage detector detects an abnormality in the commercial AC power supply, the switching circuit is energized. An uninterruptible power supply device characterized in that the gate block switch is switched and the gate block switch is closed, and the load is energized by the inverter.