KR102510026B1 - Redundant uninterruptible power supply - Google Patents

Abstract

A redundant uninterruptible power supply is provided, which has an active mode and an inactive mode, and a voltage converter for inverting and outputting the DC voltage of an internal battery into an AC voltage when commercial voltage is not input in the active mode state, and the voltage converter At least two uninterruptible power supplies (1A, 1B) including an AC switch for supplying the output of the load to the load; Among the two or more uninterruptible power supplies (1A, 1B), the presence or absence of an inverted AC voltage output from the inverter of the uninterruptible power supply (1i: where i is any one of 1A and 1B) set to the active mode and the frequency interval are detected to invert the invert A blackout of the AC voltage is detected to determine the operation mode of the UPS (1j: where j is any one of 1A and 1B, and j≠j) set to the inactive mode among the two or more UPS (1A, 1B). It consists of a UPS power outage detector that switches to active mode.

Description

Redundant uninterruptible power supply {Redundant uninterruptible power supply}

The present invention relates to an uninterruptible power supply (UPS) that inverts the voltage of a battery and supplies it to a load in the event of a power outage of a commercial power supply, and specifically, a high-speed interruption (outage) state of commercial power. The present invention relates to a redundant uninterruptible power supply having a priority output order while operating a parallel-connected uninterruptible power supply capable of quickly supplying a more stable AC voltage to a load by detecting it as a load.

In the case of a momentary power outage in a computer, especially a server or workstation, there is a very high possibility that data on the computer being worked on will be lost or sensitive hardware will be damaged. Of course, there is a program that saves periodically to prevent this, but if the voltage jumps (irregular) due to a power outage, sensitive experimental equipment is undoubtedly damaged.

In particular, the 5G communication network, more specifically, the subscriber network of the 5G communication network is inevitably sensitive to commercial power outages. If the instantaneous power failure is not actively dealt with, the quality of the communication service is deteriorated, and in severe cases, the subscriber network must be restarted.

Therefore, UPS is used in subscriber networks of computer systems and communication networks. A UPS is a device that supplies stable alternating current (AC) power of good quality to a load by overcoming a power failure that may occur in a system power source, that is, a commercial power source. The efficiency of this UPS lies in how quickly it detects a power failure state and converts the AC voltage supplied to the load into the AC voltage converted by the inverter at a fast response speed.

Such a UPS is classified into an online type or an offline type UPS, etc., and in any type of UPS, when commercial power is normally input, the DC voltage converted by the rectifier is charged in the internal battery, and the commercial power is It is configured to convert the DC voltage charged in the battery into AC through an inverter and supply it to the load when a cutoff (power failure) or voltage fluctuation is detected. The prior art of such a UPS can be exemplified by Patent No. 0923333 described in the following patent documents.

However, in a large number of conventional technologies, including those described in the above patent documents, the technical configuration for detecting the presence or absence of a power outage or voltage fluctuation of the AC voltage input to the commercial AC line (distribution line) is the presence or absence of one cycle of 200 ~ 380VAC 60Hz AC voltage and by detecting the fluctuating state, it was not possible to quickly switch the power to the output of the UPS in case of a power outage or voltage fluctuation.

In Korea, a commercial voltage has a frequency of 60 Hz, and it takes at least 16.666 ms by detecting a power outage or voltage fluctuation by detecting a zero crossing of one cycle.

The operating frequency of computers, 5G networks, and subscriber communication networks is getting higher and higher, and the switching frequency of inverters in UPS is also increasing to tens to hundreds of KHz for stable output of AC voltage and miniaturization and light weight of parts. As a cycle, power failure detection is slow, and devices that require very stable AC voltage input have no choice but to use expensive power supplies with a highly developed program operation method.

In addition, when using redundant UPSs, it is not possible to quickly detect the output voltage cutoff state of the UPS that is activated by power failure and supplies inverted AC voltage to the load. When switching to , AC voltage was not supplied to the load in a timely manner, causing problems such as malfunction of the load.

Accordingly, the inventors of the present invention intend to provide a UPS capable of rapidly supplying a stable AC voltage to a load by quickly detecting a power outage state through a simple hardware configuration.

Registered Patent Publication No. 10-0923333 B1 (registered on October 16, 2009)

The present invention has been made to solve the above problems, and the power failure state is quickly detected as a voltage level change of 1/2 cycle of the AC voltage supplied to the load, and the AC voltage is quickly inverted. Provide a UPS supplying voltage to the load.

Another object of the present invention is to sample the full-wave rectified waveform of the AC voltage with a clock of at least 240 Hz synchronized with the zero-point signal of the AC voltage, detect the presence or absence of a peak voltage through comparison with a preset first reference voltage, and detect the detected peak A UPS that switches power at high speed with a power failure detector that filters the voltage and the logical addition signal of the zero signal, compares the level with the second reference voltage, and detects the power failure state at high speed by the presence or absence of zero and peak voltage detection. is in providing

Another object of the present invention is to determine the priority of the AC voltage output of the UPS when operating at least two UPSs connected in parallel, and to automatically activate the UPS set to the lower priority when there is no output from the UPS set as the priority to load. It is to provide a UPS that continuously provides an inverted AC voltage.

The redundant uninterruptible power supply according to an embodiment of the present invention is connected between a commercial voltage (2) and a load (3), supplies the commercial voltage (2) to the load (3), and cuts off in response to a power failure detection signal. AC switch 40 to be; A converter 10 that converts the commercial voltage 2 to a DC voltage by full-wave rectification, and a power failure detector that activates the power failure detection signal when there is no voltage output from the converter 10 or a change in voltage level is detected ( 90), a battery 20 that is charged by the DC voltage and discharged by blocking the charging voltage, and an inverter 30 that outputs the DC voltage from the battery 20 as an AC voltage of a constant frequency according to the switching frequency ) and an AC switch 50 connected between the inverter 30 and the load 3 and supplying the AC voltage of the inverter 30 to the load 3 in response to the power failure detection signal, An overcharge prevention switch 70 connected between the converter 10 and the battery 20, and the overcharge prevention switch 70 is blocked when the voltage of the battery 20 exceeds a preset reference voltage OVREF An overcharge detector 80 that is connected between the inverter 30 and the AC switch 50 and is conducted by the active mode and cut off by the inactive mode to switch the output of the inverter 30 (mode switch ( 100) and two or more uninterruptible power supplies (1A, 1B) including; Presence of an inverted AC voltage output from the AC switch 50 of the UPS (1i: where i is any one of 1A and 1B) set to the active mode among the two or more UPS (1A, 1B) and frequency interval The operation of the UPS (1j: where j is any one of 1A and 1B, and j≠j) set to the inactive mode among the two or more UPS (1A, 1B) by detecting the power failure of the inverted AC voltage. It consists of a UPS power outage detector that switches the mode to an active mode.

The UPS power failure detector detects the zero point of the inverted AC voltage output from the inverter of the uninterruptible power supply (1i: where i is any one of 1A and 1B) set to the active mode among the two or more uninterruptible power supplies (1A, 1B) A zero detector outputting a zero signal; a phase-locked oscillator generating a sampling clock having a frequency at least twice the frequency of the AC voltage in synchronization with the output zero signal; A sampler for outputting a switched sampled signal; a peak voltage detector for detecting a peak voltage of a sine wave by comparing the sampled signal with a first reference voltage set to at least 1/2 of the full-wave rectified waveform; The peak voltage and the output zero point signal are logically added, integrated, and filtered, and compared with a second reference voltage set higher than the first reference voltage. When the level of the integrated voltage is less than or equal to the second reference voltage, The operation mode of the uninterruptible power supply (1j: where j is any one of 1A and 1B, and j≠j) set to the inactive mode among the above uninterruptible power supply devices (1A, 1B) is switched to the active mode.

An uninterruptible power supply device according to an embodiment of the present invention samples a waveform obtained by full-wave rectification of a commercial voltage at a sampling frequency higher than the frequency of the commercial voltage, detects the peak voltage of the full-wave rectified waveform, and obtains a zero signal of the peak voltage and the commercial voltage It detects power failure and voltage instability by the presence or absence of the zero point voltage and peak voltage of the commercial voltage by logical addition, so it has faster response to power failure and can switch the power supplied to the load from the commercial voltage to the AC voltage of the inverter. there is.

In addition, at least two or more UPS are connected in parallel to set the priority during operation, and when the output of the higher priority UPS is instantaneous or unstable, the neighboring lower priority UPS is activated to stabilize the AC voltage to the load. The reliability of the redundant uninterruptible power supply can be further increased.

1 is a block diagram of an uninterruptible power supply according to a preferred embodiment of the present invention.
2 is a detailed circuit diagram of the power failure detector shown in FIG. 1;
3a and 3b are operational waveform diagrams of FIG. 2, which are prepared in the order of FIG. 3a to FIG. 3b and collectively referred to as FIG. 3.
4 is a block diagram of a redundant uninterruptible power supply according to a preferred embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

In the following description of the invention, the detailed description of the components widely known and used in the technical field to which the present invention belongs or does not belong will be described as little as possible, which is the gist of the present invention along with omitting unnecessary descriptions. to convey more clearly.

Referring to FIG. 1, in an embodiment of the present invention, the uninterruptible power supply 1 includes a converter 10 that outputs a stable DC voltage by full-wave rectifying and filtering a commercial voltage (AVC) 2, which is largely an AC voltage, and a DC voltage A battery 20 that charges or discharges, an inverter 30 that switches the DC voltage output from the battery 20 by a switching frequency and outputs it as an AC voltage of a preset frequency, the commercial voltage 2 and the load ( 3) and connected between the inverter 30 and the load 3, respectively, and switched exclusively in response to the power failure detection signal PD, which is activated (to logic 'low') when the commercial voltage is cut off 2 It includes two AC switches (40, 50).

A DC switch 60 is connected between the battery 20 and the inverter 30, and the DC switch 60 changes the voltage of the battery 20 to the inverter in response to the power failure detection signal PD. 30) is supplied.

In the UPS 1, an overcharge prevention switch 70 is connected between an output terminal of the converter 10 and a terminal of the battery 20, and the overcharge prevention switch 70 controls the voltage of the battery 20 It is characterized in that it is blocked by the output of the overcharge detector 80 that outputs an overcharge prevention signal when the preset overcharge reference voltage OVREF is exceeded.

The uninterruptible power supply 1 of the present invention includes a power failure detector 90 that quickly detects a power failure or abnormal voltage in a time shorter than 1/2 cycle of an AC frequency and outputs a power failure detection signal PD. The power failure detector 90 is connected between the output terminal of the converter 10 and the control terminals of the two AC switches 40 and 50.

The power failure detector 90 outputs a power failure detection signal PD activated as logic “low” when power failure is detected and deactivated as logic “high” when normal, and the AC switches 40 and 50 and the DC switch ( 60) is a control terminal and is 'turned on' only when a logic 'high' signal is input.

In order for the two AC switches 40 and 50 to operate exclusively with each other, the output terminal of the phase inverter INV inverting the power failure detection signal PD output from the power failure detector 90 is connected to the DC switch 60 and the AC switch 60. It is connected to the control terminal of the switch 50.

The AC switches 40 and 50 may use relays whose contacts are turned on/off by the power failure detection signal PD or static switches that do not have movable contacts.

Reference numeral 100 not described in FIG. 1 is a mode setting switch that sets the connection of the AC voltage generated by the inverter 30 to the AC switch 50, which is used when two UPSs 1 are redundant in parallel. do. When one UPS(1) is used alone or two UPS(1) are connected in parallel in normal times, it is set to be ‘turned on’ only when set to priority, and deactivated to ‘off’ when set to lower priority. it's a mode

In the uninterruptible power supply 1 configured as shown in FIG. 1, the power failure detector 90 detects the peak voltage of the waveform full-wave rectified by the converter 10 and the zero point of the frequency of the commercial power supply, and through logical addition, the zero point of the AC signal and The power outage detection signal PD is activated only when the peak voltage located between the zero points is not continuously detected. That is, a power failure detection signal is output. The detailed configuration and operation of the blackout detector 90 will be described later with reference to FIGS. 2 and 3 .

When the commercial voltage 2 is normally input, the power failure detection signal PD output from the power failure detector 90 is logic "high". At this time, the AC switch 40 is turned on to supply the commercial voltage 2 to the load 3 so that the load 3 is operated by the commercial voltage. Of course, the power failure detection signal PD is inverted to logic 'low' by the phase inverter INV and provided to the control terminal of the AC switch 50 connected between the output terminal of the inverter 30 and the load 3 .

At this time, the AC switch 50 is turned off and the AC voltage generated from the inverter 30 is not supplied to the load 3. In addition, the DC switch 60 connected between the battery 20 and the inverter 30 is turned off to block the voltage of the battery 20 from being supplied to the inverter 30, so that when the commercial voltage is normal, the current of the battery 20 prevent wear and tear

In this state, the overcharge detector 80 outputs an overcharge prevention signal when the voltage of the battery 20 exceeds the preset overcharge reference voltage OVre. The overcharge prevention signal turns off the overcharge prevention switch 70 connected between the output terminal of the converter 10 and the terminal of the battery 20 .

If the commercial voltage 2 is not a correct sine wave due to power failure or unstable, the power failure detector 90 that inputs it outputs a power failure detection signal PD in a low state, whereby the DC switch 60 turns on, AC switch (40) is turned off, and the AC switch (50) is turned on.

At this time, the inverter 30 switches and converts the voltage of the battery 20 input through the DC switch 60 by switching frequency (PWM) to an AC voltage of a preset frequency, for example, a commercial voltage and the same voltage and frequency. By generating a voltage and supplying it to the AC switch 50, the load 3 continuously inputs the AC voltage.

2 is a diagram of a specific embodiment of the power failure detector 90 shown in FIG. 1, and FIG. 3 is an example of an operating waveform diagram of each part of FIG. Referring to FIG. 3, a detailed operation of the blackout detector 90 shown in FIG. 2 will be described.

Referring to FIG. 2, the full-wave rectifier 91, which is a part constituting the converter 10 shown in FIG. 1, full-wave rectifies the commercial voltage (220VAC) 2 of the same waveform as W1 in FIG. It outputs the voltage of the full-wave rectified waveform like W2.

The voltage of the full-wave rectified waveform W2 output from the full-wave rectifier 91 is insulated through a photocoupler 92 composed of a photodiode 93 and a phototransistor 94, and a switching transistor constituting the sampler 95. is supplied to the emitter of (96).

The sampling clock generator composed of the zero detector 97 and the phase-locked oscillator 98 detects the zero point of the AC signal, such as W1 in FIG. output like For the zero detector 97 and the phase-locked oscillator 98, well-known circuits widely used in the art may be used.

The frequency of the clock output from the phase-locked oscillator 98 is preferably twice as fast as the frequency of the commercial voltage (60 Hz), preferably four times as fast. In this way, setting the sampling clock frequency faster than the AC voltage frequency is to detect the peak voltage of the full-wave rectified 1/2 cycle pulsating current as shown in W2 of FIG. condition or voltage instability can be detected more quickly.

The switching transistor 96, which inputs the same sampling frequency as W4 in FIG. 3 as a base, is turned on/off according to the frequency of the sampling clock to sample the voltage of the full-wave rectified waveform input to the collector, and the resistor (R) connected to the emitter ) through which a waveform such as W5 in FIG. 3 is supplied to the non-inverting terminal of the first comparator 99.

The first comparator 99, as a peak voltage detector, compares the voltage of the sampled waveform as shown in W5 of FIG. 3 with a first reference voltage Vref1 set to at least 1/2 of the full-wave rectified waveform to obtain When the voltage of the waveform is higher than the first reference voltage Vref1, a peak voltage detection signal such as W6 of FIG. 3 is supplied to one input terminal of the logic adder 101.

At this time, since the zero point signal output from the zero detector 97 as shown in W3 in FIG. , and pulse trains in which the peak voltage detection signals between zero points are added are output.

The pulse train of W7 in FIG. 3 output from the logic adder 101 is input to the integrator 102, leveled with a sawtooth wave like W8 in FIG. 3, and then input to the non-inverting terminal of the second comparator 103. A second reference voltage Vref2 set lower or higher than the first reference voltage Vref1 is input to the inverting terminal of the second comparator 103 . Preferably, the second reference voltage Vref2 is set lower than the first reference voltage Vref1.

The second comparator 103 compares the second reference voltage Vref2 with the voltage leveled in the sawtooth wave, such as W8 in FIG. When low, the power outage detection signal PD is activated to 'low', the AC switch 40 is turned off, and the AC switch 50 is turned on to supply the AC voltage generated by the inverter 30 to the load 3.

That is, when the commercial AC voltage input to the converter 10 due to instantaneous power failure or temporary power voltage instability is input as unstable as P1 in W1 in FIG. 2, the level of the peak voltage of the full-wave rectified waveform is W2 in FIG. is converted as When the voltage of the full-wave rectified waveform is reduced like P2 of W2 of FIG. 3, the output of the sampler 95 that samples it with the sampling clock like W4 of FIG. 3 is sampled like W5 and P3 of FIG. It is entered as (99). Accordingly, the output of the first comparator 99 is output as shown in W6 of FIG. 3 .

At this time, the logic adder 101 logically adds the signal W6 of FIG. 3 and the zero signal W3 of FIG. 3 and provides the signal W7 of FIG. 3 to the integrator circuit 102 . That is, at this time, the integrating circuit 102 integrates pulse trains having different on/off duty as shown in W7 of FIG. That is, it outputs a filtering signal that is momentarily lowered by low voltage or momentary power failure (LD).

Therefore, the second comparator 103 that compares the output W8 of the integrating circuit 102 with the second reference voltage Vref2 sets the power failure detection signal PD to 'low' during the momentary power failure LD as shown in W9 of FIG. output as

With the above operation, if the peak voltage level or zero point of the full-wave rectified waveform is not detected due to instantaneous power failure or temporary instability of the power supply voltage, it is quickly and accurately detected and a power failure switching signal is output, thereby increasing the reliability of the power supply device. there is.

For example, when the voltage level of the second full-wave rectified waveform voltage in FIG. 3 is rapidly lowered as shown in P1 of FIG. 3 or absent due to power failure, the sampled voltage level is also lowered as shown in W5 of FIG. 99 outputs a signal of logic "low" in the section as shown in W6 of FIG.

Therefore, the integrator 102 drops as shown in the LD of W8 in FIG. 3, and the output of the second comparator 103 that detects a power failure by comparing it with the second reference voltage Vref2 is a blackout as shown in W9 of FIG. A signal representing the state is output to the AC switch 40, the phase shifter INV and the DC switch 60 as described above. At this time, since the power failure detection signal PD is logic low, the AC switches 40 and 50 transition to off and on states, respectively.

By this operation, when a power failure is detected within 1/4 cycle of the AC signal, the inverted AC voltage generated by the inverter 30 is immediately supplied to the load 3, so that the quality of the UPS 1 can be trusted.

4 is a block diagram of a redundant uninterruptible power supply according to a preferred embodiment of the present invention. In FIG. 4, reference numerals 1A and 1B represent the same configuration as the configuration of the uninterruptible power supply 1 shown in FIG. 1 except for the configuration of the AC switch 40. 4, the mode switch 100 in the uninterruptible power supplies 1A and 1B is turned on/off according to an operation sequence.

In FIG. 4 according to an embodiment of the present invention, the control terminal of the mode switch 100 in the uninterruptible power supply device 1A is set to a logic "high" to an active mode, and the mode switch 100 in the uninterruptible power supply device 1B The control terminal is connected to the output of the UPS power failure detector 90A that detects the power failure state of the inverted AC signal output from the uninterruptible power supply device 1A, that is, the error state.

The configuration of the UPS power failure detector 90A shown in FIG. 4 is also similar to the configuration of FIG. 2 described above, but when the configuration of FIG. 2 is used as the UPS power failure detector 90A of FIG. 4, input of commercial voltage 2 The terminal is connected to the output of the uninterruptible power supply 1A set to the active mode, and the power failure detection signal PD1 is connected to the control terminal of the mode switch 100 of the uninterruptible power supply 1B set to the lower priority inactive mode.

Of the two UPS devices 1A and 1B shown in FIG. 4, the UPS 1A is set to an active mode and the mode switch 100 of the UPS 1B is set to an inactive mode.

If the commercial voltage (2) is normally input in the above setting mode, the power failure detection signal (PD) output from the power failure detector 90 in the UPS (1A, 1B) is output as logic 'high', so the AC switch 40 is 'turn on', and all of the AC switches 50 in the UPS 1A and 1B are turned off. Therefore, the commercial voltage 2 is directly supplied to the load 3 through the AC switch 40.

If the commercial voltage 2 is in a power failure state, the power failure detector 90 in the UPS 1A in active mode detects the power failure state as described above and supplies the inverted AC voltage to the load 3. When the inverted AC voltage becomes unstable due to the low voltage or discharge of the battery 20 in the UPS 1A, the UPS power failure detector 90A detects that the output of the UPS 1A is in a power failure state and generates a power failure detection signal PD1. By outputting logic "high" to activate mode switch 100 in UPS 1B, the inverted AC voltage generated in UPS 1B is quickly supplied to load 3.

As described above, according to the present invention, even if the UPSs are connected in parallel and redundant, voltage switching from a higher priority UPS to a lower priority UPS can be performed quickly, thereby further increasing the reliability of the power supply.

1, 1A, 1B uninterruptible power supply
2 commercial voltage
3 loads
10 converter
11 full-wave rectifier
20 battery
30 inverter
40, 50 AC switch
60 DC switch
70 Overcharge prevention switch
80 overcharge detector
90, power failure detector
90A UPS power failure detector
91 full wave rectifier
92 Photocoupler
95 sampler
96 switching transistor
97 Zero Detector
98 phase-locked oscillator
99 first comparator
100 mode switch
101 Logical Adder
102 Integral circuit
103 second comparator
INV Inverter gate

Claims (2)

In the redundant uninterruptible power supply,
an AC switch 40 connected between the commercial voltage 2 and the load 3 to supply the commercial voltage 2 to the load 3 and to be cut off in response to a power failure detection signal;
A converter 10 that converts the commercial voltage 2 to a DC voltage by full-wave rectification, and a power failure detector that activates the power failure detection signal when there is no voltage output from the converter 10 or a change in voltage level is detected ( 90), a battery 20 that is charged by the DC voltage and discharged by blocking the charging voltage, and an inverter 30 that outputs the DC voltage from the battery 20 as an AC voltage of a constant frequency according to the switching frequency ) and an AC switch 50 connected between the inverter 30 and the load 3 and supplying the AC voltage of the inverter 30 to the load 3 in response to the power failure detection signal, An overcharge prevention switch 70 connected between the converter 10 and the battery 20, and the overcharge prevention switch 70 is blocked when the voltage of the battery 20 exceeds a preset reference voltage OVREF An overcharge detector 80 that is connected between the inverter 30 and the AC switch 50 and is conducted by the active mode and cut off by the inactive mode to switch the output of the inverter 30 (mode switch ( 100) and two or more uninterruptible power supplies (1A, 1B) including;
Presence of an inverted AC voltage output from the AC switch 50 of the UPS (1i: where i is any one of 1A and 1B) set to the active mode among the two or more UPS (1A, 1B) and frequency interval The operation of the UPS (1j: where j is any one of 1A and 1B, and j≠j) set to the inactive mode among the two or more UPS (1A, 1B) by detecting the power failure of the inverted AC voltage. A redundant uninterruptible power supply comprising a UPS power failure detector that converts the mode to an active mode.
The method of claim 1, wherein the UPS power failure detector detects a zero point of an inverted AC voltage output from an inverter of an uninterruptible power supply device (1i) set to an active mode among the two or more uninterruptible power supply devices (1A, 1B) and outputs a zero signal. a phase-locked oscillator that generates a sampling clock having a frequency at least twice the frequency of the AC voltage in synchronization with the output zero-point signal, and the full-wave rectified waveform is switched by the sampling clock and sampled A sampler for outputting a signal; a peak voltage detector for detecting a peak voltage of a sine wave by comparing the sampled signal with a first reference voltage set to at least 1/2 of the full-wave rectified waveform; The output zero signal is logically added and then integrated and filtered, compared to a second reference voltage set higher than the first reference voltage, and when the level of the integrated voltage is equal to or less than the second reference voltage, the two or more UPS Among (1A, 1B), the redundant uninterruptible power supply characterized in that the operation mode of the uninterruptible power supply (1j) set to the inactive mode is switched to the active mode.

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