JPH0463613B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an uninterruptible power source device comprising a constant voltage constant frequency power source device (hereinafter referred to as CVCF), a storage battery, and a charger.

[Technical background of the invention and its problems] Uninterrupted power supply is a necessary condition for computer power supplies.
Therefore, conventionally, it consists of a forward conversion device and an inverse conversion device.
An uninterruptible power supply system consisting of a CVCF, a storage battery, and a charger that constantly floatingly charges the storage battery has been adopted. Additionally, separately excited forward converters using thyristors or diodes have been used in chargers, and in the case of thyristors, constant voltage control has been performed. However, CVCF is a source of harmonic current, and as its capacitance increases, it often causes harmonic interference on the input side.

[Object of the Invention] The present invention uses a self-extinguishing element in a charger to provide a charging function and a harmonic removal function to eliminate harmonic current.

[Summary of the Invention] The present invention provides a system consisting of a CVCF, a storage battery, and a charger, in which the charger is configured with a voltage-type inverter that uses self-extinguishing elements, and the charger maintains a constant voltage of the storage battery. This is an uninterruptible power supply device that is characterized by reducing harmonic current on the AC input side.

[Embodiments of the Invention] Next, embodiments of the present invention will be described. FIG. 1 shows a forward converter 1 for converting AC power supplied from an AC power source 4a.
After converting to DC power with e, the inverter 1b
CVCF to obtain constant voltage constant frequency power by converting power with
1, and a storage battery 2 that supplies DC power to the inverse conversion device 1b via the semiconductor switch 1c connected in parallel to the DC side of the forward conversion device 1e when the power supply from the AC power source 4a is stopped. In the uninterruptible power supply, a current transformer 1a is connected to the AC power source 4a side of the forward converter 1e and measures the alternating current supplied to the forward converter 1e, and one end is connected to the current transformer 1a.
is connected to the AC power source 4a side, and the other end is connected to the storage battery 2
A voltage-type inverter 3c that is connected to the inverter 3c and charges the storage battery 2 or returns power to the AC power source 4a through an antiparallel circuit of diodes and self-extinguishing elements, and an AC power source 4 of the inverter 3c.
A current transformer 3e that is connected to the side of a and measures the alternating current flowing to the inverter 3c, and a current transformer 1a.
A filter 3f is connected to the next winding and extracts the harmonic component flowing to the current transformer 1a, and the output signal of the filter 3f and the current signal output to the secondary winding of the current transformer 3e are compared and the output signal of the inverter 3c is This figure shows an uninterruptible power supply including a control circuit 3h that outputs a control signal to a self-extinguishing element.

That is, an inverter 3c consisting of a diode and a self-extinguishing element in antiparallel is used in the conversion circuit of the charger 3.

The inverter 3c is controlled by both constant voltage control 3b and current control 3d. Then, the floating voltage of the storage battery is given by the constant voltage control 3b, the input current of the CVCF1 is detected by the current transformer 1a, the harmonic component is extracted by the filter 3f, and the constant voltage component is adjusted to the current level by the V/I converter 3g. The current flowing through the current transformer 3e of the charger 3 is controlled by the inverter 3c, using the sum of the converted value and the harmonic current as a reference.

Next, another embodiment of the present invention is shown in FIG.
The operation of CVCF1 is similar to that shown in FIG. In voltage control, the voltage of the storage battery 2 is fed back to the voltage control circuit 17 in order to control the DC voltage of the storage battery 2 as a DC source at a constant level by the charger 5.

CVCF1 is always controlled by the signal from the current control circuit 16.
In order to supply a current that cancels the harmonic current generated by the inverter 3c, the inverter 3c is controlled by pulse width modulation (PWM). A power failure signal is input from the power failure detection circuit 19 to the current control circuit 16, and the signal from the current control circuit 16 stops the inverter 3c. Also, at this time, the DC source storage battery 2 is CVCF
1 is used for uninterrupted operation.

[Effects of the Invention] According to the present invention, the high frequency current generated by the CVCF is absorbed by the charger, and a constant floating voltage is applied to the battery.

To summarize the above effects, by using a voltage source inverter that functions as an active filter in the charger, the storage battery voltage can be maintained and
The harmonics on the CVCF input side are removed, and this system can become a harmonic-free uninterruptible power source.

[Brief explanation of drawings]

FIGS. 1 and 2 are single-line diagrams of an uninterruptible power supply device showing an embodiment of the present invention. 1...CVCF, 1a...Current transformer, 2...Storage battery, 3...Active filter, 3b...Constant voltage control, 3c...Inverter, 3d...Current control,
3e...Current transformer, 3f...Filter, 4...Input, 14...Load, 15b...Current detector, 16
...Current detector, 17...Voltage control circuit, 19...
...Power failure detection circuit.

Claims (1)

[Claims] 1. A constant voltage constant frequency power supply device that converts AC power supplied from an AC power source into DC power using a forward conversion device and then converts the power again using an inverse conversion device to obtain constant voltage constant frequency power; In an uninterruptible power supply device comprising a storage battery that supplies DC power to the inverse converter through a semiconductor switch connected in parallel to the DC side of the forward converter when the power supply is stopped, a first current transformer connected to the AC power source side of the converter to measure the AC current supplied to the forward converter; one end connected to the AC power source side of the first current transformer; A voltage type inverter device whose end is connected to the storage battery and which charges power to the storage battery or returns power to the AC power source by an anti-parallel circuit of diodes and self-extinguishing elements; and the AC power source of this inverter device. a second current transformer connected to the side and measuring the alternating current flowing through the inverter device;
a filter device connected to the secondary winding of the first current transformer to take out harmonic components flowing to the first current transformer; and an output signal of this filter device and two of the second current transformer. An uninterruptible power supply comprising: a control circuit that compares current signals output to the next winding and outputs a control signal to a self-extinguishing element of the inverter device.