KR20030018685A - Uninterruptible Power Supply Apparatus - Google Patents

Abstract

PURPOSE: A high efficiency DC and AC output uninterruptable power supply is provided to prevent a temporary power outage, while reducing the volume and weight of the power supply by eliminating the necessity of using a transformer. CONSTITUTION: A high efficiency DC and AC output uninterruptable power supply comprises a rectifying unit(21) for converting commercial power into direct current; a charging control unit(22) for preventing over charging of voltage/current while the power output from the rectifying unit is charged in batteries(24,25); batteries charged with the DC power output from the rectifying unit; a diode(26) for automatically converting the power output to an output terminal of the uninterruptable power supply into the power for the rectifying unit and the battery, by using the difference between the voltage of the rectifying unit and the voltage of the battery; and an over discharge control unit(23) for preventing over discharge of the battery while the power of the battery is discharged to the output terminal of the uninterruptable power supply.

Description

High Efficiency DC / AC Combined Output Uninterruptible Power Supply {Uninterruptible Power Supply Apparatus}

The present invention relates to a high efficiency DC-AC composite output uninterruptible power supply (UPS) for supplying power uninterrupted.

In general, an uninterruptible power supply (UPS) is an uninterruptible power supply device for the purpose of supplying a normal power supply to a device requiring electricity in case of power failure without notice or excessive voltage drop due to an accident.

DC power supplies of most electronic and electrical products currently commercialized worldwide employ Switched Mode Power Supply (SMPS), which is highly efficient, compact, and light in weight. It is a method of converting into direct current by using switch element after converting to direct current, so it does not matter whether AC is input or DC is input.

In particular, when AC is input into a digitized device, a lot of harmonics and surge currents flow, causing malfunctions, and a malfunction of a corporate computer caused by such causes causes tremendous economic loss, thus providing a stable and pure solution without these problems. DC power supply is a must.

An uninterruptible power supply of the prior art will be described with reference to the accompanying drawings.

1 is a block diagram illustrating a configuration of an uninterruptible power supply according to a conventional technology. The uninterruptible power supply of the prior art receives a commercial AC power and lowers the transformer 11 to an appropriate voltage to charge electrical energy to a battery. And a rectifying unit 12 for converting alternating current output from the transformer 11 into direct current, a battery 13 for charging direct current output from the rectifying unit 12 and discharging during power failure, and a battery power source when a commercial power supply is out of power. Inverter 14 for converting AC into AC and boosting power, and a switching switch 15 for connecting a UPS output terminal to commercial power when commercial power is normal, and connecting the output of inverter 14 to a UPS output terminal when commercial power is out of power. It is composed of

Referring to the operation of the conventional uninterruptible power supply configured as described above, when the commercial power is normal, the commercial power is directly connected to the UPS output terminal through the changeover switch 15 and at the same time the voltage is dropped by the transformer 11 and the rectifier 12 After rectifying through the battery 13 and charging the battery 13, when the commercial power is outage, the power of the battery 13 is converted into alternating current by the inverter 14 and stepped up by a transformer (not shown) to be switched through the changeover switch 15. It is connected to the UPS output terminal.

In the conventional uninterruptible power supply, power loss of only several% occurs only in the input transformer 11, and power loss occurs again in the rectifying process of the rectifying unit 12 to charge the battery 13. The power loss of several to several tens percent occurs in the inverter 14 including the process of converting the DC power charged in the battery 13 to AC and the transformer boosting it. 10-15% power is lost inside a typical UPS.

In addition, when the commercial power supply is normal and when a power failure occurs, the power supply is generally switched in a relay manner, and a power outage of tens of ms to hundreds of ms is inevitable in the UPS output terminal.

In the case of a UPS having a large capacity because the transformers in the input transformer 11 and the inverter 14 are very heavy, the weight of the transformer may be hundreds of kilograms or more.

The present invention to solve the various problems in the conventional uninterruptible power supply as described above significantly improves the inefficient power efficiency, and the instantaneous power failure that occurs when switching from commercial power to battery power and vice versa Its purpose is to provide a high efficiency DC / AC composite output uninterruptible power supply that can significantly reduce volume and weight while eliminating it.

1 is a block diagram illustrating a configuration of an uninterruptible power supply according to the prior art.

2 is a block diagram illustrating a DC uninterruptible power supply (UPS) portion of a high efficiency DC / AC combined output uninterruptible power supply according to the present invention.

3 is a block diagram illustrating an AC power converter according to the present invention.

4 is a diagram illustrating a dead time waveform.

※ Explanation of code about main part of drawing ※

21: rectifier 22: charge control unit

23: over-discharge control unit 24: battery 1

25: battery 2 26: diode

31: 30,720 Hz Inverter 32: 256: 1 Frequency Division

33: 60Hz 50% Duty Circuit Part 34: Dead Time Circuit Part

35 switch element driving unit 36 bridge AC power conversion unit

37: changeover switch

The present invention for achieving the above object is a rectifying unit for converting commercial power to direct current, and a charging control unit for preventing overcharge voltage and current while the commercial power is normally charged from the rectifier output to the battery And is separated into two and is output to the UPS output terminal according to the normal and power failure of the commercial power by using a difference between the battery of the DC power rectified by the rectifier and the voltage of the rectifier and the voltage of the battery; And a diode for automatically switching power to the rectifier unit or the battery power in an orderless manner, and an overdischarge control unit for preventing overdischarge of the battery while discharging the power of the battery to the UPS output terminal due to a power failure of commercial power. It features.

According to another embodiment of the present invention, an AC power converter is further provided, wherein the AC power converter generates a 30,720 Hz pulse and generates three independent 12V power supplies for driving the switching elements of the bridge AC power converter. And a 256: 1 frequency divider for dividing 30,720Hz of the 30,720Hz inverter into one-half of 256 to make 120Hz, and a 50% duty cycle simultaneously with 120Hz of the 256: 1 frequency divider at 60Hz. 60Hz 50% duty circuit for generating duty cycle, dead time circuit for protecting each switching element of the bridge AC power converter, bridge AC power conversion for converting DC power of battery into AC power Switching element driver for controlling the driving of the negative switching element, and a plurality of switching elements are switched by the control of the switching element driver unit and the power source of the battery The bridge AC power converter, a commercial power supply and the bridge AC power converting portion for converting the output power into AC power to a switching switch for switching to the UPS output terminals is preferred.

Hereinafter, a high efficiency DC / AC combined output uninterruptible power supply according to the present invention will be described in detail with an exemplary drawing.

2 is a circuit diagram for explaining the configuration of the DC UPS portion of the high-efficiency DC-AC combined output uninterruptible power supply according to the present invention.

Referring to FIG. 2, the present invention converts a commercial AC input power into a direct current to a rectifier 21 and a direct current output from the rectifier 21 is controlled to a proper voltage and current to the batteries 24 and 25. The charging control unit 22 to charge, the over-discharge control unit 23 to prevent the over-discharge fatal to the life of the battery 24, 25 when the commercial power supply is out of power, and the battery to charge the electric energy when the commercial power is normal The power is supplied to the UPS output terminal through the diode 26 when the commercial power is normal, and the battery power is supplied through the diode 26 to the batteries 24 and 25 when the commercial power is normal. A diode 26 is supplied to the output terminal.

Referring to the operation of the high-efficiency DC-AC combined output uninterruptible power supply according to the present invention configured as described above, first, when the commercial AC power is normal, AC is converted into DC by the rectifier 21, and the DC power is the diode 26. Is supplied directly to the UPS output terminal. In addition, the two batteries 24 and 25 are charged by the control of the charging control unit 22 which controls the electric energy output from the rectifying unit 21 to the optimum charging voltage and current suitable for the battery.

When a power failure or abnormality of the commercial power source occurs, the electric energy charged in the batteries 24 and 25 is immediately supplied to the UPS output terminal through the diode 26 without interruption of power. At this time, the over-discharge control unit 23 performs a function for preventing the over-discharge fatal to the life of the battery (24, 25). At this time, an unillustrated relay connected to the over-discharge control unit 23 is always in an "on" state, and when the voltage of the batteries 24 and 25 is discharged below a preset voltage, the relay is automatically switched to an "off" state. The above discharge is interrupted.

Separating the battery from the battery 24 and the battery 25 from above not only facilitates maintenance, but also charges power of the battery 25 to 24V, and supplies the power of the battery 25 to the charging control unit ( 22 and to the driving power of the over-discharge control unit 23.

In the present invention as described above, the UPS capacity can be freely set only by the capacity selection of the rectifier 21, the diode 26, the battery 24, and the battery 25.

As an example, in the case of a 110V UPS, a battery 25 having a voltage of 96V may be mounted. In the case of a 200V UPS, a battery having a voltage of 216V may be mounted in a design.

3 is a block diagram illustrating an AC power converter in the high efficiency DC / AC combined output uninterruptible power supply according to the present invention.

Referring to FIG. 3, the AC power converter includes a 30,720 Hz inverter 31 which generates a pulse of 30,720 Hz and generates three independent 12 V power sources for driving the switching element of the bridge AC power converter 36. A 256: 1 frequency divider 32 that divides 30,720 Hz of a Hz inverter into one-half of 256 to make 120 Hz, and a 50% duty while simultaneously setting 120 Hz of the 256: 1 frequency divider 32 to 60 Hz. 60 Hz 50% duty circuit section 33 for generating a duty cycle, dead time circuit section 34 for protecting each switching element of the bridge AC power converter 36, and a DC power supply of the battery. A switching element driver 35 for controlling the driving of the switching element of the bridge AC power converter 36 for converting the AC power into AC power, and a plurality of switching elements switched by the control of the switching element driver 35. Bridge AC power to convert power to AC power It consists of the output power of the affected part 36, a commercial power source and AC bridge power converter 36 to the changeover switch 37 to switch to the UPS output.

Referring to the AC power converter configured as described above, when the commercial power is normal, the commercial power is outputted to the output terminal by the operation of the changeover switch 37, but when the commercial power is out of power, De-energize) supplies 24V of battery power to the 30,720Hz inverter 31 to operate and supply driving power to each circuit.

Here, the 30,720Hz inverter 31 supplied with the battery generates a 30,720Hz pulse used as a source of 60Hz, and converts the 24V input power into three independent 12V powers and outputs the same. Three 12V power sources output from the 30,720Hz inverter 31 are used as driving power sources of the bridge AC power converter 36.

The 30,720Hz pulse generated by the 30,720Hz inverter 31 is divided into 120Hz through a 256: 1 frequency divider 32 composed of eight 1/2 frequency dividers. That is, it divides into 1/256.

In general, an electric device that operates only with alternating current power requires an alternating current power source having a duty cycle of 50% of one cycle and one cycle of alternating cycle. This is to balance the current flowing in the constant and reverse cycles.

However, the pulse period output from the 256: 1 frequency divider 32 is not a pulse of 50% duty. Thus, by having a 50% duty circuit section 33 composed of edge trigger flip-flops divided into 2: 1, a square wave having a 60 Hz 50% duty is output to the output terminal Q and the output terminal ( Can be obtained from Here, the output terminal (Q) and the output terminal ( ) Phase is completely reversed.

When the bridge AC power converter 36 is directly driven by using the pulses converted into the frequency and duty ratio by the 60Hz 50% duty circuit 33 in this manner, there is a possibility that the switching device, which is a semiconductor device, may be damaged.

The characteristics of an active semiconductor device have an "on" delay time and an "off" delay time. The "off" delay time is much longer than the "on" delay time. Because of this characteristic, in the bridge connection circuit, the opposite device is switched to the "on" state before the symmetrical device is completely "off", causing a short circuit and the device is broken.

Referring to the operation of the element having such characteristics on the basis of the bridge AC power converter 36, the switching element A and the switching element D are turned "on" during the constant cycle of the AC power supply, and then the switching element A during the next cycle. Switching elements B and C should be in the "on" state after and D are in the "off" state. However, during the "off" delay time of the switching elements A and D, the switching elements B and C are turned "on", and the switching elements A and C and the "on" states of the switching elements B and D overlap with each other, causing a short circuit. The switching element, which is a semiconductor element, is broken.

In order to prevent such a phenomenon, a dead time must be given between the AC cycles as shown in FIG. 4. This role is the dead time circuit section 34 composed of the TTL IC and the RC circuit. In the present invention, the dead time of about 47 ms is considered in consideration of the maximum "off" delay time of each type of high-power semiconductor switching device, and this dead time does not cause any trouble to the equipment using the general power supply. .

The switching element driver 35 receiving the dead time pulse from the dead time circuit unit 34 is connected to two pairs of switching elements of the bridge AC power converter 36, namely, A and D and B and C. It is driven by the intersection every half cycle.

In the above, since the source of the switching device C and the switching device D is in phase, the 12V power supply is shared, and the source of the switching device A and the switching device B is driven by each independent 12V power supply. . The switching device driver 35, the switching device A, and the switching device B preferably transmit a driving signal to an electrically insulated photocoupler.

As the switching element of the bridge AC power converter 36, a MOS FET, an IGBT, a transistor module, or the like may be used, and it is preferable to selectively use the switching element according to the UPS capacity.

According to the present invention, the DC UPS of the high-efficiency DC-AC combined output uninterruptible power supply can utilize at least 99% of the power charged in the battery at the load without using a power conversion circuit. When commercial power is recovered, there is no power disconnection when switching to commercial power. Even if you select AC power converter and use it as AC UPS, it has more than 98% power use efficiency. It is effective to realize UPS production.

Claims (2)

Rectifier for converting commercial power into direct current; A charging control unit for preventing an overcharge voltage and current while a commercial power source normally charges a battery output from the rectifier unit; A battery configured to be separated into two and charge the DC power rectified by the rectifier; A diode which automatically converts power output from the UPS output terminal into the rectifier unit or the battery power in an orderless manner by using a difference between the voltage of the rectifier unit and the voltage of the battery; And An over-discharge control unit for preventing over-discharge of the battery while discharging the power of the battery to the UPS output terminal due to a power failure of commercial power; High efficiency DC-AC combined output uninterruptible power supply comprising a. The method of claim 1, Further comprising an AC power converter, the AC power converter, A 30,720 Hz inverter generating a pulse of 30,720 Hz and generating three independent 12 V power supplies for driving the switching elements of the bridge AC power converter; A 256: 1 frequency divider for dividing 30,720Hz of the 30,720Hz inverter into one half of a 256 to 120Hz; A 60Hz 50% duty circuit for generating 50% duty cycle while simultaneously making 120Hz of the 256: 1 frequency division unit 60Hz; A dead time circuit unit for protecting each switching element of the bridge AC power converter; A switching element driver for controlling driving of the switching element of the bridge AC power converter to convert the DC power of the battery into AC power; A bridge AC power converter having a plurality of switching devices switched under control of the switching device driver and converting a battery power into AC power; And A switching switch for switching the output power of the commercial power supply and the bridge AC power conversion unit to a UPS output terminal; High efficiency DC-AC combined output uninterruptible power supply comprising a.