JP2655153B2 - Uninterruptible power supply output synchronization - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an uninterruptible power supply, and provides such an uninterruptible power supply with a uniform power supply output waveform having no phase shift irrespective of normal and power failures. The present invention relates to an uninterruptible power supply output synchronization method, and more particularly to an uninterruptible power supply output synchronization method in which a commercial power supply waveform before the power failure and an output waveform using a battery after the power failure are output in synchronization.

2. Description of the Related Art Conventionally, in a computer system such as a personal computer, an OA device, and an FA device, for example, a voltage of a computer system during operation due to an unexpected power outage of a commercial power supply or an improper load on a commercial power supply user side. An uninterruptible power supply is used to cope with a power supply accident such as an abnormal drop. As shown in FIG.
The input AC is normally stored in the battery 4 via the charger 3 and the stored DC is exchanged for AC by the inverter 5 and output to the output terminal 7 via the switching means 6 in normal times. It has become.

(Problems to be Solved by the Invention) In the above-described technology, it is rare that the waveform output by the switching of the power supply system at the time of power failure by the uninterruptible power supply becomes uniform and continuous (FIG. 3). . A conventional inverter output waveform from an uninterruptible power supply starts from a fixed direction and outputs a waveform from, for example, a negative side. For this reason, a power failure occurs when the commercial power supply waveform changes from the negative side to the positive side, and the inverter output waveform may start from the negative side and become completely out of phase as shown in FIG. At this time, for example, when the load is a transformer or the like, magnetic saturation occurs when the power supply system is switched, and a large inrush current may flow through the load. For example, there is a problem that an inrush current of 100A or more flows even with a transformer of about 5A, which sometimes has a serious adverse effect on a load system.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problem, and an object of the present invention is to provide an uninterruptible power supply output synchronization system in which an inrush current when switching a power supply system is minimized.

(Means for Solving the Problems) The uninterruptible power supply output synchronizing method according to the present invention is used in an uninterruptible power supply that outputs the power of a battery charged when the power supply is normal via a converter when the power supply is abnormal. An input phase detection circuit that detects a phase of a waveform and outputs pulses corresponding to positive and negative, a two-phase division circuit that divides a square wave generated from a square wave generation circuit into an odd-numbered wave and an even-numbered wave, and an input pulse. Switch means for an inverter of an uninterruptible power supply that forms different phase waveforms, wherein a pulse waveform from the input phase circuit is input to the two-phase split circuit to select an odd-numbered wave and an even-numbered wave; And forming a waveform having the same phase as the power supply waveform immediately before the power failure from the commercial power supply.

(Operation) The square wave output from the square generating circuit is divided into its odd-numbered wave and even-numbered wave by a two-phase dividing circuit. On the other hand, when the input phase detection circuit detects the positive side and the negative side of the power supply waveform, it outputs a pulse waveform. With this output, one of the odd-numbered square wave and the even-numbered square wave is selected, and one of them is supplied to the inverter. Output. FIG. 3 shows the waveform obtained as described above. As shown in the figure, in this waveform, the waveform 8 before the power failure and the inverter output waveform 10 have the same phase, and the inrush current is minimized.

(Embodiment) Next, an uninterruptible power supply output synchronization system according to an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a circuit diagram of an example of an uninterruptible power supply output synchronizer using an uninterruptible power supply output synchronization system of the present invention. In the figure, reference numeral 11 denotes an input terminal of a commercial power supply. It is connected, and the AC waveform 12 of 100 V is normally input here. Reference numeral 13 denotes an input phase detection circuit, which is formed of, for example, a comparator 14, an AND element 15, a power failure detection circuit 16, and the like. The input phase detection circuit 13 outputs pulses 19 and 20 for notifying the positive and negative sides 17 and 18 of the AC waveform 12 supplied from the commercial power supply. Reference numeral 21 denotes a square wave generating circuit which outputs a square wave 22. Reference numeral 23 denotes a two-phase dividing circuit, which is formed using, for example, a D flip-flop 24, an AND element 25, and the like. This two-phase dividing circuit 24
The pulse 22 is divided into an odd-numbered wave 26 and an even-numbered wave 27, and either of them is enabled (enabled) by the pulses 19 and 20 and output. The selected waveform is the switching element 30a or 3 at both ends of the primary coil 29 of the inverter 28.
The drive pulse becomes 0b.

Next, an example of the operation of the apparatus embodying the uninterruptible power supply output synchronizing method according to the present invention will be described. The commercial power supply ends with a negative waveform such as waveform 8 in FIG.
Occurs, pulse 20 occurs immediately before this power failure (“H”
Level), and the Q terminal of the D flip-flop 24 is enabled. At this time, the square wave generation circuit 21 outputs the square wave 22, and the odd-numbered wave 26 is output from the AND element 25a. The output odd-numbered wave 26 becomes a drive pulse for the switching element 30a of the inverter 28 as described above, and thus, when a power failure occurs, the DC of the battery
And a synchronized AC output is obtained at the output terminal 33 via the secondary coil 32.

(Effects of the Invention) By adopting the uninterruptible power supply output synchronization method of the present invention having the above-described configuration, when a power failure occurs at the time of a power failure, the waveforms of the commercial power supply and the uninterruptible power supply are synchronized when the power supply is switched. Since the output is obtained, no rush current is involved. Therefore, there is an industrially remarkable effect that a high-quality AC that does not adversely affect the load can be supplied.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of an embodiment of a synchronizer using an uninterruptible power supply output synchronization system of the present invention, FIG. 2 is a block diagram of an example of a conventional uninterruptible power supply, FIG. FIG. 4 is a diagram showing an abnormal waveform. In the figure, 13: input phase detection circuit, 21: square wave generation circuit, 23: 2
Phase division circuit.

Claims (1)

(57) [Claims] An uninterruptible power supply that outputs the power of a battery charged when a power supply is normal through a converter when a power supply is abnormal, detects a phase of a waveform at the time of a power failure of a commercial power supply, and outputs pulses corresponding to positive and negative. An input phase detection circuit, a two-phase division circuit that divides a square wave generated from a square wave generation circuit into an odd-numbered wave and an even-numbered wave, and an inverter of an uninterruptible power supply that forms a different phase waveform by an input pulse. A switch means, and a pulse waveform from the input phase circuit is input to the two-phase division circuit to select an odd-numbered wave and an even-numbered wave, select the switch means of the inverter, and immediately before a power failure from the commercial power supply. An uninterruptible power supply output synchronization method characterized by forming a waveform having the same phase as the power supply waveform.