JPH02131334A - Uninterruptible power source equipment - Google Patents

Abstract

PURPOSE:To reduce the size and the weight of an uninterruptible power source equipment by connecting an AC power source through a switchgear with a load and with an inverter provided with a battery and normally operating the inverter in charger mode while an inverter mode upon occurrence af power interruption. CONSTITUTION:An AC power source 1 is connected through a switchgear 2 with a load 7 and with the AC output side of an inverter 50. The inverter 50 has DC input side connected with a battery 4, and the operating mode thereof is switched between charger mode and inverter mode through a control circuit 56 from the output of a power interruption detecting circuit 8. The switchgear 2 is normally turned ON to feed AC voltage to the load 7 and the inverter 50 thus charging the battery 4. Upon detection of power interruption, the switchgear 2 is turned OFF and the inverter 50 is brought into inverter mode through a connecting circuit 56 to produce AC power which is fed to the load 7. Circuits 51-56 constituting the inverter 50, as well as high frequency transformer 53, are formed of high frequency parts. By such arrangement, a small, light and safety uninterrubtible power source equipment can be constituted.

Description

Detailed Description of the Invention "Field of Industrial Application" The present invention relates to an uninterruptible power supply device for supplying uninterrupted AC power to communication devices and computers, and in particular to an uninterruptible power supply device that allows an inverter to also operate as a charger. This article relates to an uninterruptible power supply that is smaller, lighter, and more economical.

``Prior Art'' Conventionally, as this type of uninterruptible power supply, the system shown in FIG. 1 has been proposed (Japanese Patent Publication No. 49-41734).

In this figure, an AC power source such as a commercial power source is connected to a load 7 via a switch 2, an inverter 5 is connected to a rechargeable storage battery 4, an inverter 5 is connected to the load via a switch 3, and a switch A reactance circuit 6 is connected in parallel with 3. The switch 2 is turned on when the AC power supply 1 is normal, and turned off during a power outage, and the switch 3 operates in the opposite direction to the switch 2. That is, the switch 3 is off when the AC power supply I is normal, and is turned on during a power outage. The reactance circuit B6 is mainly composed of an actor, a capacitor, or a reactor and a capacitor.

In this circuit, when the AC power supply I is normal, the switch 2 is on, and AC power is directly sent to the load 7. On the other hand, the imperter 5 receives power from the storage battery 4, outputs an AC voltage synchronized with the voltage of the AC power source I, and is connected to an AC power source via an actance circuit 6 on its output side. At this time, the switch 3 is off. Here, by delaying the phase of the output of the inverter 5 from the AC power supply I, power flows from the AC power supply 1 to the inverter 5, and the inverter 5
operates as a charger and charges the storage battery 4.

When AC power supply 1 has a power outage, switch 2 is turned off and switch 3 is turned off.
By turning on the AC output of the inverter 5, the AC output of the inverter 5 is fed to the negative electrode 7. Generally, when the output sides of two AC power supplies are connected and a voltage difference or phase difference is given between them, current flows from one power supply to the other power supply in accordance with the difference. In other words, a galvanic current occurs.

In this conventional example, since the output side of the AC power supply 1 and the inverter 5 are always connected, the reactance circuit 6 is essential in order to suppress the cross current flowing due to the phase difference and voltage difference between the two power supplies. The reactor and capacitor used in this reactance circuit 6 must be designed to operate at commercial frequency, which increases both size and weight. Furthermore, in order to supply power from the inverter 5 to the load 7 during a commercial power outage, a switch 3 for short-circuiting the reactance circuit 6 is required. In this way, conventional uninterruptible power supplies
There were problems in that the size and weight of the device increased, and economic efficiency was impaired.

The purpose of this invention is to solve these problems by creating a compact and
The object of the present invention is to provide a lightweight, economical, uninterrupted IT source device.

"Means for Solving the Problem" According to this invention, an AC power source is connected to a load via a switch, and a storage battery is connected to the load via an inverter circuit, and the inverter circuit is connected to a DC filter section, a high frequency inverter section, and a high frequency inverter section. The control circuit section controls the inverter circuit in charger mode or inverter mode, and in the charger mode, the frequency converter section controls the inverter circuit. The AC power of the power supply is converted to high frequency AC, isolated by a high frequency transformer, and converted to DC by the high frequency inverter.In inverter mode, the DC power of the IT battery is converted to high frequency AC by the high frequency inverter, and the high frequency transformer It is insulated and the frequency converter converts the dark wave number to supply power to the load, and the power failure detection circuit detects the presence or absence of AC power.
A signal for controlling the switch and switching between the two operating modes is given to the control circuit section.

"Embodiment" FIG. 2 shows an embodiment of the present invention. In FIG. 2, the inverter 50 includes a DC filter 51 and a high frequency inverter section 52.
, a high frequency transformer 53, a frequency converter 54, an AC filter 55, and a control circuit 56. Further, a power outage detection circuit 8 detects a power outage of the AC power supply 1. Other numbers that are the same as those in Figure 1 indicate the same items. Next, the operation of this invention will be explained. When the AC power supply l is normal, the switch 2 is turned on and power is supplied to the load 7.

In addition, the inverter 5o is connected to the AC power source 1 through the switch 2.
As input, it is working as a charger. That is,
The AC power passes through the AC filter 55 and is then supplied to the frequency converter 5.
4 and is converted into a high frequency AC voltage. This high frequency voltage is insulated by a high frequency transformer 53, rectified by an inverter section 52, and becomes a DC voltage. The riffle component contained in this DC voltage is reduced by the DC filter 5l, and the storage battery 4 is charged.

When the AC power source 1 is out of power, the power outage detection circuit 8 generates a signal to turn off the switch 2 and switch the operation mode of the control circuit 56 to inverter mode. In the inverter mode, the DC power of the storage battery 4 is input to the inverter section 52 through the DC filter 5l, and is converted into a high frequency AC voltage. This high frequency voltage is insulated by a high frequency transformer 53 and input to a frequency conversion section 54. The frequency converter 54 converts the frequency into a low-frequency AC voltage by repeating a sub-mode in which the high-frequency voltage is passed as is and a sub-mode in which it is switched in the positive or negative direction within a fixed period according to a separately generated pulse width modulation signal. This AC voltage is supplied to the load 7 after harmonic components are removed by an AC filter 55 .

Next, a specific example of the inverter 5G and the control circuit 56 will be shown, and operations in charger mode and inverter mode, and operations during mode switching will be described in detail.

FIG. 3 shows an example of a specific circuit of the inverter 50. In the high frequency inverter section 52, semiconductor switches SzSz are connected in series, semiconductor switches Sff+34 are connected in series, and both series connections are connected in parallel and connected to the DC filter 51. ．． Semiconductor switch S + ,
The connection point of Sz and the connection points of S3 and S4 are connected to one winding of the high frequency transformer 53. semiconductor switch S
+ “” Diode D in antiparallel with S 4 respectively.
ID4 is connected. In the frequency converter 54, the semiconductor switches SII+S1 are connected in series, the semiconductor switches s13+SI4 are connected in series, and these series connections are connected in parallel and connected to the AC filter 55, and the semiconductor switches S13+SI4 are connected in series. I+S
The connection point of I2 and the connection point of SIff+Sl4 are connected to the other winding of the high frequency transformer 53. The semiconductor switches Sll to SI4 are, for example, Swiss elements that can be controlled in both directions as shown in FIG. Further, FIG. 5 shows an example of a specific block configuration of the control circuit. Furthermore, Fig. 6 shows an example of the drive waveform and main voltage waveform (when the polarity of the AC power supply is in the positive direction) of each semiconductor in charger mode, and Fig. 7 shows an example of each semiconductor in inverter mode. Figure 8 shows examples of voltage waveforms for the main parts of the main circuit in inverter mode. The operation of the control circuit when the AC power supply is normal will be explained with reference to FIG.
4 is turned off, and the switches S and S4 are turned off.

Further, the signal from the power failure detection circuit 8 is input to the switching circuit 511, and the switching circuit 511
, 505 is output to the drive circuit 513. On the other hand, the reference oscillator 502 generates a signal synchronized with the AC power supply by the synchronization circuit 501, and the FF5
05, a phase shift circuit 503 generates a phase-shifted signal, and the generated signal is input to the FF 504. FF
The output signal of FF 504 is a signal out of phase with the signal of FF 505, and these signals are input to the drive circuit 513 through the switching circuit 511 to generate the drive signals of Suinochi SL1 to SL4 (Sll to S14 in FIG. 6). . In response to these drive signals, the frequency converter 54 converts the semiconductor switch S I I ” S I 4 as shown in FIG.
According to the cycle shown below, alternating current voltage can be converted into high frequency alternating current? Convert to pressure v1.

■By turning on the switch SLI+S+a, a positive voltage is generated in the high frequency transformer 53. (2) By turning on the switches S I l + S I 3, the excitation current of the high frequency transformer 53 is circulated. No voltage is generated in the high frequency transformer 53.

(2) By turning on the switches S12 and SI3, a voltage in the negative direction of the high frequency transformer 53 is generated.

(2) By turning on the switches S+ (2) and S14, the excitation current of the high frequency transformer 53 is circulated. No voltage is generated in the high frequency transformer 53.

The high frequency AC voltage V, thus obtained, is rectified by the diodes D, ~D4 of the high frequency inverter section 52.
It is smoothed by passing through the DC filter 51,
Charge the storage battery 4.

Next, the operation when the AC power supply 1 experiences a power outage will be explained with reference to FIG.
504 and 505 to generate ON signals for the switches Sl to S4, and at the same time operate the switching circuit 511 so that the output signal of the switch decision logic circuit 510 is output to the drive circuit 5.
13.

On the other hand, since the input signal to the synchronization circuit 5010 disappears, the reference oscillator 502 oscillates at an independent frequency, and the phase shift circuit 5010 oscillates at an independent frequency.
3. The FFs 504 and 505 generate signals in the same way as when the AC power supply is normal. Unlike when the AC power supply is normal, these signals are transmitted through the drive circuit 514 to the drive signal St.
-Sn (SI"S4 in FIG. 7), and drives the switches 81 to S4 of the high frequency inverter section 52. The signal of the reference oscillator 502 is input to the PWM signal generation circuit 506, the sine wave generation circuit 507, the carrier A triangular wave generation circuit 508 generates a sine wave and a carrier triangular wave synchronized with the reference oscillator 502, and compares them with a comparison amount 509 to generate a PWM (pulse width modulation) signal.This PWM signal and the sine wave generator The output of PwM 507 is input to a switch determination logic circuit 510 to generate a signal that determines the driving timing of each switch of the frequency conversion section 54.
Since the signal is a signal that takes the "0" level or the "1" level, for example, when the PWM signal is at the "0" level, the submode is set in which high frequency AC voltage is passed regardless of the signal from the sine generator 507. When the PWM signal is "1" level and the polarity of the sine wave generator 507 is positive, the sub-mode rectifies in the positive direction, and when it is negative, it rectifies in the negative direction. A signal that determines the drive signal timing is output to each submode to be rectified.

These signals are sent to the drive circuit 51 through the switching circuit 511.
3, and the drive signal S.3 is input to S.3. ~s, 4 (Fig. 7 Sll~
S14) becomes.

In response to the above signal groups 31-S4 and Sl1-314, the inverter 50 performs the following operation as shown in FIG. The high frequency inverter section 52 generates a high frequency AC voltage (2) on the primary side of the transformer 53 through the following cycle.

(2) By turning on switches SI and 84, a positive voltage is generated in the high frequency transformer 53.

(2) By turning on the switches St and Sa, the excitation current of the high frequency transformer 53 is circulated. No voltage is generated in the high frequency transformer 53.

(2) By turning on the switches St and Ss, a negative voltage is generated in the high frequency transformer 53. ■Suisochi Sz. By turning on Sa, the high frequency transformer 5
The excitation current of No. 3 is circulated. No voltage is generated in the high frequency transformer 53. The generated high frequency alternating current voltage (3) is manually input to the frequency converter 54 via the high frequency transformer 53. The frequency converter 54 operates in three sub-modes: a sub-mode in which the high-frequency AC voltage is passed through as is, a sub-mode in which synchronous rectification is performed in the positive direction, and a sub-mode in which synchronous rectification is performed in the negative direction. In the sub-mode in which the high-frequency AC voltage V is synchronously rectified in the positive direction, the semiconductor switch of the frequency converter 54 is operated as follows.

■Since the output of the high frequency inverter section 52 is in the positive direction,
Turn on Swissochi S I I + S + 4,
Rectify in the positive direction.

■、■ Is the output of the high frequency inverter section 52 zero voltage? Since there is a switch SI,, SI4 or SIl+ 3 +
Turn on ■ to circulate the output current.

■Since the output of the high frequency inverter section 52 is in the negative direction,
Switches S1■+S+3 are turned on to perform synchronous rectification in the positive direction.

In addition, in the sub-mode where the signal is passed through as it is, (1), (2) the output of the high frequency inverter section 52 is a voltage in the positive direction or in the negative direction, so the Swiss S314 or SL! , Sl:l
is turned on and the high frequency AC voltage is passed through as is.

(2) Since the output of the high frequency inverter section 52 is zero voltage, the switch SIff+SI4 or S++, S+ (2) is turned on to circulate the output current.

Furthermore, in the sub-mode in which synchronous rectification is performed in the negative direction, (1) the output of the high frequency inverter section 52 is in the positive direction, so the switches S1 (2), S1, are turned on to perform rectification in the negative direction.

(2) Since the output of the high frequency inverter section 52 is zero voltage, the switch Slff+S+4 or SII+S+1 is turned on to circulate the output current.

■Since the output of the high frequency inverter section 52 is in the negative direction,
The switch S II+ 3 14 is turned on to perform rectification in the negative direction.

These three submodes are controlled by the PWM signal generation circuit 506.
By repeating the process according to the output of V3 and the output signal of the sine wave generator 507, the output V3 of the high frequency inverter section 52 becomes a pulse width modulated voltage waveform (4) as shown in FIG. 8, and is passed through the AC filter 55. This results in a sinusoidal AC voltage. By adjusting the output level of sine wave generator 507, the output level of inverter 50 can be adjusted.

Switching between the charger mode and the inverter mode is performed by a signal from the power failure detection circuit 8, as described above. That is, when the AC power supply 1 has a power outage, the power outage detection circuit 8 generates a signal and gives the signal to the drive circuit 514 in FIG.
Swiss drive signal S, ~S4 of high frequency inverter section 52
At the same time, the switching circuit 511 turns off the switch 3.
The drive sequence of 11 to sea is switched from FIG. 6 to the sequence of FIG. 7. As is clear from FIGS. 6 and 7, this switching is completed within one cycle of the operating frequency of the high-frequency inverter section 52 and the frequency converter section 54, so the output of the inverter 50 changes almost simultaneously with the power outage of the AC power aX. It is possible to supply power to the load 7 without momentary interruption.

Also, when the AC power supply 1 is restored, the power failure detection circuit 8 still generates a signal, and the synchronization circuit 501 controls the output of the reference oscillator 502 and therefore the inverter 50 to be synchronized with the AC power supply 1. , switch 2 in Fig. 2
is turned on, and the control signal of the inverter 50 is switched from the sequence shown in FIG. 7 to the sequence shown in FIG. 6. The switching at this time is also 1 of the operating frequency of the frequency converter 54.
Complete within the cycle. Therefore, power can be supplied to the load 7 without momentary interruption, and charging of the storage battery 4 can be started immediately, thereby shortening the charging time.

FIG. 9 shows a second specific example of the control waveform of the charger mode of the inverter 50 shown in FIG. 3. By the way, number one? The control waveform shown in the figure is the same as the control waveform of the first specific example shown in FIG. 6, and only the switch element to be controlled is different. Therefore, since the circuit shown in FIG. 5 can be applied as is to the control circuit that outputs the waveform shown in FIG. 9, a description of the configuration and operation of the control circuit for generating the control waveform shown in FIG. 9 will be omitted. Next, Figures 3 and 9
The operation of this specific example will be explained using the diagram. In this specific example, in the charger mode of the inverter 50, the inverter 5
The feature is that 0 operates as a boost type. That is, switch S. and S1■ are turned on at the same time, energy is stored in the AC filter actor (■), and then,
Suisochi SI! By turning off S+a and turning on S+a, the voltage of the reactor of the AC filter 55 is superimposed on the voltage of the AC power supply 1 and applied to the high frequency transformer 53 (■)
. Next, switch S. By turning off the switch Sl4 and turning on S13, energy is stored in the reactor of the AC filter 55 again (■), and further, by turning off the switch Sl4, the switch S13 is turned on.
By turning on 1■, a voltage of opposite polarity to the previous one is applied to the high frequency transformer 53 (■). By repeating this operation, the voltage applied to the high frequency transformer 53 becomes an AC voltage (1) which has a higher voltage value than the AC voltage.
This voltage (1) is rectified by the diodes D1 to D4 of the high frequency inverter section 52, becomes a DC voltage, and charges the storage battery through the DC filter 51. The operation in the inverter mode is the same as that in the first specific example shown in FIGS. 7 and 8, so a description thereof will be omitted. Further, the switching between the inverter mode and the charger mode is the same as in the first specific example.
Since the process is completed within a cycle, it is possible to achieve output without interruption. In this specific example, since a voltage Vl higher than that of the AC power source 1, and therefore a high DC voltage, can be obtained, charging can be performed even when the storage battery voltage is high, and furthermore, the storage battery 4 can be charged efficiently. There is.

As described above, in the uninterruptible power supply according to the present invention, the inverter 50 operates at a high frequency and switches between the inverter mode and the charger mode within one cycle of the operating frequency, so that the output can be uninterrupted, and it can also operate at low frequencies. Since no moving parts are used, the device can be made smaller and lighter. Furthermore, since the input and output of the inverter 50 are insulated by the high frequency transformer 53, the AC current 1! The storage battery 4 can be grounded even in the electrical circuit where the line A1 is grounded, and especially when a high voltage storage battery 4 is used, the safety of the device can be extremely high in terms of human body safety.

"Effects of the Invention" As explained above, according to the present invention, an uninterruptible power supply is configured using an inverter that operates at high frequency and has input and output isolated, and does not use any parts that operate at low frequency. Since there is no output, it is possible to provide a small, lightweight, and economical uninterruptible power supply device that is safe for human health because the output is uninterrupted.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a conventional uninterruptible power supply, and FIG. 2 is a block diagram showing an embodiment of the uninterruptible power supply of the present invention.
Fig. 3 is a connection diagram showing a specific example of an inverter circuit, Fig. 4 is a diagram showing a specific example of a bidirectional switch, and Fig. 5 is a connection diagram showing a specific example of an inverter circuit.
'11 A block diagram showing a specific example of the circuit. Figure 6 is a diagram of the drive waveforms of each semiconductor switch and voltage waveforms of the main parts of the inverter circuit of Figure 3 in charger mode. Figure 7 is a diagram of the inverter circuit of Figure 3. Figure 8 is a voltage waveform diagram of the main parts of the inverter circuit in the inverter mode of Figure 3. 2 is a second specific example of drive waveforms of each semiconductor switch in charger mode and voltage waveform diagrams of main parts. Patent applicant Nippon Telegraph and Telephone Corporation

Claims (1)

[Claims] (1) A switch for connecting an AC power supply and a load, a storage battery, an inverter circuit having the storage battery as an input side and an output terminal connected to the load side of the switch, and a power failure detection circuit, The circuit includes a DC filter section, a high frequency inverter section, a high frequency transformer, a frequency conversion section, an AC filter section, and a control circuit section, the control circuit section controlling the inverter circuit in a charger mode or an inverter mode, In the charger mode, the frequency converter converts AC power of the AC power source into high frequency AC,
The high-frequency transformer insulates the battery, and the high-frequency inverter section converts the DC power into direct current; The converter converts the frequency and supplies power to the load, and the power outage detection circuit detects the presence or absence of the AC power supply and controls the switch, and transmits a signal for switching between the two operation modes to the control circuit. An uninterruptible power supply device characterized by supplying power to a circuit section.