JPS61244232A - Power failure free power source unit - 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] Industrial applications The present invention relates to an uninterruptible power supply.

B0 Summary of the Invention The present invention provides an uninterruptible power supply that supplies power from a battery in place of the AC power supply during a power outage, in which power is supplied by a rectifier when the AC power supply is normal; The battery is charged to a voltage lower than the output voltage of the rectifier by a power conversion means provided on the output side of the rectifier, and the charge of the battery is supplied via a diode in the event of a power outage of the AC power supply. This improves the input blockage during steady operation when the AC power source is healthy, and eliminates the need for switching operations during power outages, increasing the reliability of the device.

C0 Prior Art Conventional uninterruptible power supplies have adopted either a floating charging type or a DC switch type. A floating charging type uninterruptible power supply is configured as shown in FIG. 4, for example. Fourth
In the figure, reference numeral 1 denotes a thyristor rectifier that converts AC power introduced from an AC power source (not shown) into DC, and is configured by, for example, thyristors connected in a bridge. When the AC power supply is normal, the thyristor rectifier 1 charges the battery 2, and at the same time, the thyristor rectifier M1 supplies DC power to the inverter 4 via the DC reactor 3. Further, during a power outage of the AC power supply, DC power is supplied from the battery 2 to the inverter 4 via the DC reactor 3. Note that 5 in FIG. 4 is a smoothing capacitor. A DC switch type uninterruptible power supply is configured as shown in FIG. 5, for example.

In FIG. 5, a rectifier 11 rectifies an AC input from an AC power source (not shown), and is configured by, for example, connecting diodes in a bridge. When the AC power supply is normal, the output power of the rectifier 11 is supplied to the inverter 4 via the DC reactor 3, and the sum of the output power of the rectifier 11 and the thyristor rectifier 1 is used to supply the battery 2.
is charged.

Further, in the event of a power outage of the AC power supply, a control circuit (not shown) turns on the thyristor switch 12 to supply the charging voltage of the battery 2 to the inverter 4.

D0 Problems to be Solved by the Invention The uninterruptible power supply device using the floating charging method shown in FIG. The disadvantage is that it is bad. For this reason, there were problems such as the need to increase the capacity of the transformer provided on the input side of the thyristor rectifier fil.

Further, in the case of the uninterruptible power supply using the DC switch method shown in FIG. 5, when the AC power supply is normal, the DC power rectified by the rectifier 11 is supplied to the inverter 4, so the fundamental wave power factor is 1. However, during a power outage of the AC power supply, it is necessary to turn on the thyristor switch 12 and switch to the battery 2 side. Therefore, a control device is required to perform switching during a power outage, making the overall configuration of the device extremely complicated.

Additionally, there were other problems such as low reliability of the device.

The present invention has been made in view of the above points, and an object of the present invention is to provide an uninterruptible power supply having a simple device configuration, a good input power factor, and high reliability.

Means for Solving the E0 Problem The present invention comprises a rectifier which is formed by bridge-connecting diodes and rectifies the output power of an AC power source, an inverter which converts the DC output power of the rectifier into AC, and a rectifier on the output side of the rectifier. The present invention is characterized in that it includes a power conversion section for charging the battery, and a diode for guiding the charging voltage of the battery to the inverter.

70 Operation In the device configured as described above, when the AC power supply is normal, power is supplied by the rectifier and the battery is charged by the power converter to a voltage lower than the output voltage of the rectifier. As a result, the input power factor becomes 1 when the AC power supply is normal. Furthermore, in the event of an AC power outage, the charging voltage of the battery is automatically supplied to the inverter via the diode. This eliminates the need for switching operations during power outages, improving the reliability of the device.

G6 Embodiment An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, the same parts as in FIGS. 4 and 5 are shown with the same reference numerals, and the explanation thereof will be omitted. Rectifier 11
A positive output terminal of the rectifier 11 is connected to a negative output terminal of the rectifier 11 via a DC reactor 3 and an inverter 4. Between the positive and negative output terminals of the rectifier 11, a power converter, for example, a step-down chopper circuit 21, and a battery 2 having the polarity shown are connected in series. A common connection point 22 between the step-down chopper circuit 21 and the battery 2 is connected to an anode of a diode. The cathode of this diode n is connected to the positive output terminal of the rectifier 11. The step-down chopper circuit 21
is configured as shown in FIG. 2, for example.

That is, a series circuit consisting of a transistor 31 and a reactor 32, which are controlled to turn on and off by a control circuit (not shown), is inserted in the electrical path connecting the positive output terminal of the rectifier 11 and the anode of the diode device, and the transistor 31
A diode of the illustrated polarity is connected between the common connection point of the reactor 32 and the negative electrode bus line N.

In the device configured as above, first the AC power supply (
(not shown), the DC output of the rectifier all is supplied to the inverter 4 via the DC reactor 3. At this time, by controlling the transistor 31 of the step-down chopper circuit 21 on and off, the DC output voltage of the rectifier 11 is stepped down, and the battery 2 is charged. That is, the charging voltage of the battery 2 is set lower than the DC voltage applied to the inverter 4 when the AC power source is healthy. In this way, when the AC power supply is normal, the output of the rectifier 11 with bridge-connected diodes is supplied to the inverter 4, so the input power factor of the device is 1, and the diode device is reverse biased and in an off state. Next, when the AC power supply fails, the output voltage of the rectifier 11 becomes zero, and the charging voltage of the battery 2 is automatically supplied to the inverter 4 via the diode and the DC reactor 3. In this way, the operation of switching to battery 2 during a power outage is not necessary, so the reliability of the device is high.

The power conversion section of the present invention may use a thyristor converter as shown in FIG. FIG. 3 shows another embodiment of the present invention, in which a thyristor converter 41 is used in place of the step-down chopper circuit 21 in FIG.
It has the same configuration as the figure. Cyrisk Compa°-Y4
It is assumed that the input side of No. 1 is connected to an AC power source (not shown). In the device configured as shown in FIG. 3, when the AC power supply (not shown) is normal, the DC output of the rectifier 11 is supplied to the inverter 4 via the DC reactor 3. At this time, the phase of the thyristor converter 41 is controlled by a control circuit (not shown) to output a negative voltage to the rectifier 11 (that is, the thyristor converter 41 is operated as an inverter). As a result, the rectifier 11
The battery 2 is charged with the voltage difference between the thyristor converter 41 and the thyristor converter 41, and the diode 23 is in an off state. Furthermore, when the AC power supply fails, the output voltage of the rectifier 11 and the thyristor converter 41 becomes zero, and the charging voltage of the battery 2 is automatically supplied to the inverter 4 via the diode n and the DC reactor 3. In this way, when the AC power supply is normal, the rectifier 11 with bridge-connected diodes
Since the output of the inverter 4 is supplied to the inverter 4, the input power factor of the device is 1. Furthermore, since there is no need to switch to battery 2 during a power outage, the reliability of the device is high.

Effects of the Invention As described above, according to the present invention, the input power factor is 1 when the AC power supply is normal, there is no need to switch to the battery during a power outage, and the device is simplified. is obtained.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing one embodiment of the present invention, and Fig. 2 is a circuit diagram showing an embodiment of the present invention.
FIG. 3 is a circuit diagram showing another embodiment of the present invention, and FIGS. 4 and 5 are both circuit diagrams showing a conventional uninterruptible power supply. 2...Battery, 4...Inverter, 11...
Rectifier, 21... Step-down chopper circuit, 23... Diode, 41... Thyristor converter. Figure 1 starts from Figure 2. En 21 bucks 1,000 cups. Figure 3 starts from Figure 4.

Claims (1)

[Claims] A rectifier that is formed by bridge-connecting diodes and rectifies the output power of an AC power supply, an inverter that converts the DC output power of the rectifier to AC, and a power conversion section that is provided on the output side of the rectifier and that charges the battery. and a diode for guiding the charging voltage of the battery to the inverter.