JP2000358378A - Uninterruptible power supply equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an uninterruptible power supply equipment, which can keep the capacitor voltage at the positive and the negative side at prescribed values, regardless of an unbalanced load and can prevent generation of positive and negative asymmetry in the output voltage or overvoltage trip, and thereby can supply stabilized output. SOLUTION: A series circuit of a battery 20 and a switching element 21 for a battery is connected to a common line 50, to which one end of an AC power supply 1 and of the AC output and a mutual connection point between a positive-side capacitor 11 and a negative-side capacitor 12 are connected. When the power outage of the AC power supply 1 is detected, the connection to a reactor 3 is switched from the AC power supply 1 to the series circuit, to charge the positive-side capacitor 11 and the negative-side capacitor 12, independently by the on/off operation of the switching element 21 for a battery and a switching element 10 in a bidirectional switch 107.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an uninterruptible power supply, and more particularly to an AC uninterruptible power supply including an inverter circuit for converting an AC voltage to a DC voltage and then converting the AC voltage to an AC voltage again, and a battery. is there.

[0002]

2. Description of the Related Art As a conventional technique, FIG.
1 shows an uninterruptible power supply disclosed in Japanese Patent No. 168867. This uninterruptible power supply includes a changeover switch 2, capacitors 11 and 12, and a battery 20 as an auxiliary power supply.
, A power failure detection circuit 23, a chopper circuit 104, an inverter circuit 105, and a filter circuit 106, and a ground line of the AC power supply 1 is connected to a series connection point of the capacitors 11 and 12.

The chopper circuit 104 includes a diode 102
Switching element 100 connected in anti-parallel to
And 101, and this series circuit is connected in parallel to the series circuit of the capacitors 11 and 12, and the series connection point of the switching elements 100 and 101 is connected to the reactor 3 to form a chopper circuit. .

The inverter circuit 105 includes a diode 15
And 16 connected in antiparallel to switching elements 13 and 1
4 series circuits, and this series circuit is connected in parallel to the series circuit of the capacitors 11 and 12 to form an inverter circuit. The output voltage of the inverter circuit 105 is generated between the connection point between the switching elements 13 and 14 and the connection point between the capacitors 11 and 12, and this output voltage is applied to the reactor 1
Filter circuit 10 including capacitor 7 and capacitor 18
6 to the load 19.

An AC power supply 1 and a battery 20 are connected to the changeover switch 2. The AC power supply 1 and the battery 20 are switched according to a command from a power failure detection circuit 23, and either one of them is connected to the reactor 3. The negative side of the battery 20 includes the switching elements 101 and 14 and the capacitor 12
Connected to

In the uninterruptible power supply having the above circuit configuration, when the AC power supply 1 is in a normal state, the changeover switch 2 is switched to the AC power supply 1 side.

In the period of the positive half cycle of the AC power supply 1,
When the switching element 101 is turned on, the path of the AC power supply 1-the reactor 3-the switching element 101-the capacitor 12-the AC power supply 1 is energized, and energy is accumulated in the reactor 3. Next, when the switching element 101 is turned off, the energy stored in the reactor 3 is released to the path of the reactor 3-diode 102-capacitor 11-AC power supply 1-reactor 3, and the capacitor 11 is charged. In the negative half cycle of the AC power supply 1, the capacitor 12 is similarly charged by controlling the switching element 100 to turn on and off.

By controlling the current flowing through reactor 3 in this manner, the voltage of capacitors 11 and 12 becomes a DC voltage having a higher value than the voltage of AC power supply 1.
The DC voltage of the capacitors 11 and 12 turns ON / OFF the switching elements 13 and 14 in the inverter circuit 105.
By the OFF operation, the voltage is inversely converted to an AC voltage, and a harmonic component is removed by the filter circuit 106 and applied to the load 19.

When the AC power supply 1 fails, a power failure detection circuit 2
According to the command of 3, the changeover switch 2 is switched to the battery 20 side, and the battery 20 and the reactor 3 are connected. At this time, the chopper circuit 104 operates as a booster circuit and obtains a predetermined DC voltage from the voltage of the battery 20.

In this case, the energy is stored in the reactor 3 by turning on the switching element 101 and energizing the path of the battery 20, the reactor 3, the switching element 101 and the battery 20, and then the switching element 101. Is turned off, the energy accumulated in the reactor 3 is released to the path of the reactor 3-diode 102-capacitor 11-capacitor 12-battery 20-reactor 3, and the capacitors 11 and 12 Is also charged to a high DC voltage.

Thereafter, as in the case where the AC power supply 1 is normal,
The voltage is converted into an AC voltage by the inverter circuit 105, and a sine wave AC voltage is applied to the load 19 through the filter circuit 106.

[0012]

Since the conventional uninterruptible power supply is configured as described above, when the AC power supply 1 is out of power and power is supplied from the battery 20,
If the load 19 is an unbalanced load, the capacitor 1
Although the capacitors 1 and 12 are charged with the same charging current, the two capacitor voltages may be unbalanced, that is, one capacitor voltage may increase and the other capacitor voltage may decrease. . in this case,
There has been a problem that the output voltage of the inverter circuit 105 becomes positive / negative asymmetric or, in the worst case, an overvoltage trip occurs.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and can maintain the positive and negative capacitor voltages at a predetermined value despite load imbalance. It is an object of the present invention to provide an uninterruptible power supply capable of supplying a stable output by preventing the occurrence of voltage asymmetry or overvoltage trip.

[0014]

In order to achieve the above object, an uninterruptible power supply according to the present invention comprises a series connection of a positive side capacitor and a negative side capacitor, one end of an AC power supply and one end of an AC output. And a common line connecting the positive side capacitor and the interconnection point of the negative side capacitor, and connected via a reactor to the other end of the AC power supply, from a positive half cycle of the voltage of the AC power supply A chopper circuit that obtains a positive DC voltage and charges the positive side capacitor, obtains a negative DC voltage from a negative half cycle and charges the negative side capacitor, and the positive side capacitor and the negative side capacitor. An inverter circuit for re-converting the charged positive and negative DC voltage to an AC voltage, and a series circuit of a battery and a battery switching element connected to the common line. When a power outage of the AC power supply is detected, the connection to the reactor is switched from the AC power supply to the series circuit, and the on-off operation of the switching element for the battery and the switching element in the chopper circuit causes the switching of the positive side. And the negative-side capacitor are charged separately.

In the uninterruptible power supply according to the present invention, the positive side capacitor is charged by the on / off operation of the switching element in the chopper circuit with the battery switching element in an on state, and the switching in the chopper circuit is performed. The element is turned on to charge the negative-side capacitor by an on / off operation of the battery switching element.

In the uninterruptible power supply according to the next invention, a backflow prevention diode is connected in series to the battery switching element.

An uninterruptible power supply according to the next invention comprises a series connection of a positive side capacitor and a negative side capacitor, one end of an AC power supply and an AC output, and one of the positive side capacitor and the negative side capacitor. A common line connected to an interconnection point, connected to the other end of the AC power supply via a first reactor, to obtain a positive DC voltage from a positive half cycle of the voltage of the AC power supply, A chopper circuit that charges a capacitor and obtains a negative DC voltage from a negative half cycle to charge the negative-side capacitor, and converts the positive and negative DC voltages charged in the positive-side capacitor and the negative-side capacitor into an AC voltage. An inverter circuit that reconverts the
A series circuit of a switching element for charging a negative capacitor connected between a positive terminal of the positive capacitor and the common line, and a second reactor; a switching element for charging the negative capacitor; 2 having a diode connected between the interconnection point of the two reactors and the negative terminal of the negative capacitor, and a battery connected to the common line, and detecting a power outage of the AC power supply. ,
The connection to the first reactor is switched from the AC power supply to the battery, and the on-off operation of the switching element for charging the negative capacitor and the switching element in the chopper circuit causes the positive capacitor and the negative The side capacitors are individually charged.

In the uninterruptible power supply according to the present invention, the positive side capacitor is charged by the energy of the battery by the on / off operation of the switching element in the chopper circuit, and the switching element for charging the negative side capacitor is provided. The negative side capacitor is charged by the energy of the positive side capacitor in the on / off operation of the above.

The uninterruptible power supply according to the next invention comprises a positive-side capacitor and a negative-side capacitor connected in series, one end of an AC power supply and an AC output, and the positive-side capacitor and the negative-side capacitor. A common line connected to an interconnection point, connected to the other end of the AC power supply via a first reactor, to obtain a positive DC voltage from a positive half cycle of the voltage of the AC power supply, A chopper circuit that charges a capacitor and obtains a negative DC voltage from a negative half cycle to charge the negative-side capacitor, and converts the positive and negative DC voltages charged in the positive-side capacitor and the negative-side capacitor into an AC voltage. An inverter circuit that reconverts the
A battery connected to the common line, a series circuit of a second reactor and a diode connected between the common line and the negative terminal of the negative capacitor, and a mutual circuit of the second reactor and the diode. A switching element for charging a negative-side capacitor connected between a connection point and a positive-side terminal of the battery; and when a power outage of the AC power supply is detected, the connection to the first reactor is made. Switching from an AC power supply to the battery, and separately charging the positive-side capacitor and the negative-side capacitor by turning on and off a switching element for charging the negative-side capacitor and a switching element in the chopper circuit. It is.

In the uninterruptible power supply according to the present invention, the positive side capacitor is charged with the energy of the battery by the on / off operation of the switching element in the chopper circuit, and the switching element for charging the negative side capacitor is charged. The on-off operation charges the negative-side capacitor with the energy of the positive-side capacitor.

In the uninterruptible power supply according to the next invention, the switching element in the chopper circuit is a bidirectional switch.

In the uninterruptible power supply according to the next invention, when the AC power supply is normal, the battery is charged by discharging the energy stored in the second reactor.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an uninterruptible power supply according to the present invention will be described below in detail with reference to the accompanying drawings. FIG. 7 shows an embodiment of the present invention.
The same components as those of the conventional example are denoted by the same reference numerals as those of the conventional example, and the description thereof will be omitted.

Embodiment 1 FIG. 1 shows a first embodiment of an uninterruptible power supply according to the present invention. This uninterruptible power supply comprises a changeover switch 2, diodes 4, 5,
A positive-side capacitor 11 and a negative-side capacitor 12 connected in series, a battery 20 as an auxiliary power supply, a power failure detection circuit 23, an inverter circuit 105 including switching elements 13, 14, diodes 15, 16; A filter circuit 106 including a capacitor 18; diodes 6 to 9;
Switch 107 according to
07 acts as a chopper circuit.

The diodes 4 and 5 are connected in series, and this series circuit is connected in parallel with the series circuit of the capacitors 11 and 12, and the series connection point of the diodes 4 and 5 is connected to the reactor 3. The positive-side capacitor 11 and the negative-side capacitor 12 connected in series are connected to the positive-side DC bus 5
1 and a negative DC bus 52, and a series connection point is connected to a common line 50 connected to one terminal of the AC power supply 1.

A common line 50 connected to one terminal of the AC power supply 1 has a negative terminal of the battery 20, a connection point of the capacitors 11 and 12, and a diode 8 which is one terminal of the bidirectional switch 107. 9 and the filter 10
One of the terminals of the capacitor 18 constituting the capacitor 6 is connected. In other words, the common line 50 connects one end of each of the AC power supply 1 and the AC output to an interconnection point of the positive side capacitor 11 and the negative side capacitor 12. The other terminal of the bidirectional switch 107, the connection point between the diodes 6 and 7, is connected to the connection point between the reactor 3 and the diodes 4 and 5 connected in series.

The positive terminal of the battery 20 is connected to the collector of the battery switching element 21, and the emitter of the battery switching element 21 is connected to the common line 50 to switch the battery switching element 21. The diode 22 is connected to the connection point with the switch 2, and the anode terminal of the diode 22 is connected to the negative DC bus 52.

The other terminal of the AC power supply 1 and a battery 20 via a battery switching element 21 are connected to the changeover switch 2.
The AC power supply 1 is controlled by a command from the power failure detection circuit 23.
And the battery 20 via the battery switching element 21, and one of them is connected to the reactor 3.

The bidirectional switch 107 is connected to the other end of the AC power supply via the reactor 3, and supplies a positive DC voltage from a positive half cycle of the voltage of the AC power supply 1 by turning on / off the internal switch element 10. Then, the capacitor 11 on the positive side is charged, and a negative DC voltage is obtained from the negative half cycle to charge the capacitor 12 on the negative side. The inverter circuit 105 includes:
The positive and negative DC voltages charged in the positive-side capacitor 11 and the negative-side capacitor 12 are converted again into an AC voltage.

Next, the operation of the first embodiment having the above configuration will be described. When the AC power supply 1 is in a normal state, the changeover switch 2 is switched to the AC power supply 1 side, and the AC power supply 1 and the reactor 3 are connected.

During the positive half cycle of the AC power supply 1, the switching element 10 in the bidirectional switch 107 is turned on, so that the AC power supply 1-reactor 3-diode 7-switching element 10-diode 9-AC power supply 1 The path is energized and energy is stored in the reactor 3. Next, when the switching element 10 is turned off, the energy stored in the reactor 3 is released to the path of the reactor 3-the diode 4-the capacitor 11-the AC power supply 1-the reactor 3, and the positive side capacitor 11 is charged. .

In the negative half cycle of the AC power supply 1, the AC power supply 1-diode 8-switching element 10
-The diode 6-the reactor 3-the path of the AC power supply 1 is energized, and energy is stored in the reactor 3. Next, when the switching element 10 is turned off, the energy stored in the reactor 3 is released to the path of the reactor 3-the AC power supply 1-the capacitor 12-the diode 5-the reactor 3, and the negative-side capacitor 12 is charged. .

When the AC power supply 1 fails, a power failure detection circuit 2
3, the changeover switch 2 is switched to the battery 20 side via the battery switching element 21, and the battery switching element 21 and the reactor 3 are switched.
Is connected. At this time, the switching element 10 in the bidirectional switch 107 and the switching element 21 for the battery are used.
By the on / off operation of 21, the positive side capacitor 11 and the negative side capacitor 12 can be charged individually.

First, the charging operation of the positive side capacitor 11 will be described. When the switching element 21 for the battery is turned on and the switching element 10 in the bidirectional switch 107 is turned on, the battery 20-the switching element 21 for the battery-the reactor 3-the diode 7-the switching element 10-the diode 9-the battery 20 The path is energized and energy is stored in the reactor 3. Next, when the switching element 10 is turned off while the battery switching element 21 is kept on, the energy accumulated in the reactor 3 is stored in the reactor 3-the diode 4-the capacitor 11-the battery 20-the battery switching element 21-. It is discharged to the path of the reactor 3 and the capacitor 11 is charged.

Next, charging of the negative side capacitor 12 will be described. When the switching element 10 in the bidirectional switch 107 is turned on and the battery switching element 21 is turned on, energy is accumulated in the reactor 3 along the same path as described above. Next, the energy stored in the reactor 3 is turned off by turning off the battery switching element 21 while the switching element 10 is kept on, so that the energy stored in the reactor 3 is switched to the diode 7-the switching element 10-the diode 9-the capacitor 12-.
Discharged to the path between the diode 22 and the reactor 3, the capacitor 12 is charged.

By the above operation, the capacitors 11 and 12 can be charged to a voltage higher than the voltage of the battery 20. The voltages charged in the capacitors 11 and 12 are applied to the switching elements 13 and 14 of the inverter circuit 105 as in the case of the circuit of FIG.
Is converted into an AC voltage by the ON / OFF operation of the filter circuit, the harmonics are removed by the filter circuit 106, and the resultant is applied to the load 19 as a sine wave AC voltage.

During operation with the battery 20, as described above, the switching element 10 and the battery switching element 21 in the bidirectional switch 107 are alternately turned on and off, and the positive-side capacitor 11 and the negative-side capacitor 12 can be individually charged, and even when the load 19 is unbalanced, the voltages of the positive-side capacitor 11 and the negative-side capacitor 12 can be controlled to desired values, respectively. Also does not cause output voltage imbalance or overvoltage trip.

Further, the chopper section is connected to the bidirectional switch 107.
With this configuration, the number of switching elements can be reduced, and a small and inexpensive configuration can be achieved.

Embodiment 2 FIG. 2 shows a first embodiment of the uninterruptible power supply according to the present invention. In this embodiment, an on / off switch 24 is used instead of the changeover switch 2 in the first embodiment shown in FIG.
A backflow prevention diode 25 is provided between the battery switching element 21 and the battery 20 in series with the battery switching element 21, and a connection point between the battery switching element 21 and the diode 22 is connected to the reactor 3 and the switch 24. Are connected to the connection point. In FIG. 2, components denoted by the same reference numerals as those in FIG. 1 perform the same operations, and a description thereof will be omitted.

In the circuit shown in FIG. 2, when the AC power supply 1 is in a normal state, the on / off switch 24 is turned on and the battery switching element 21 is turned off. In this state, the battery 20 enters a sleep state. When the AC power supply 1 loses power, the ON / OFF switch 24 is turned off by a command from the power failure detection circuit 23, and the AC power supply 1 is disconnected.
The other charging operations of the capacitors 11 and 12 are the same as in the first embodiment.

In the second embodiment, the backflow prevention diode 25 is provided in series with the battery switching element 21. Therefore, the switch 2 is turned on instead of the changeover switch 2 of the first embodiment shown in FIG. Even if the off switch 24 is used, the positive side capacitor 11 and the negative side capacitor 12 can be charged alternately, and the switch portion can be configured at low cost.

Embodiment 3 FIG. 3 shows a third embodiment of the uninterruptible power supply according to the present invention. In this embodiment, a chopper circuit 10 composed of switching elements 26 and 27 and diodes 28 and 29 is used instead of the bidirectional switch 107 in the first embodiment shown in FIG.
8 is used. Note that, in FIG. 3 as well, those denoted by the same reference numerals as those in FIG. 1 perform the same operations.
The description thereof is omitted.

Next, the operation of the third embodiment will be described. When the AC power supply 1 is in a normal state, the changeover switch 2
Is switched to the AC power supply 1 side, and the AC power supply 1 and the reactor 3 are connected.

In the positive half cycle of the AC power supply 1, the switching element 26 in the chopper circuit 108 is turned on, so that the path of the AC power supply 1, the reactor 3, the diode 4, the switching element 26 and the AC power supply 1 is energized. , The energy is stored in the reactor 3. Next,
When the switching element 26 in the chopper circuit 108 is turned off, the energy stored in the reactor 3 is changed to the reactor 3-diode 4-diode 28-capacitor 11
-Discharged to the path of the AC power supply 1-the reactor 3 and the positive side capacitor 11 is charged. At this time, the switching element 27 in the chopper circuit 108 is kept off.

In the negative half cycle period of the AC power supply 1, the path of the AC power supply 1, the switching element 27, the diode 5, the reactor 3, and the AC power supply 1 is energized to store energy in the reactor 3. Next, the switching element 27 in the chopper circuit 108 is turned off, and the energy stored in the reactor 3 is discharged to the path of the reactor 3-the AC power supply 1-the capacitor 12-the diode 29-the diode 5-the reactor 3 to release the capacitor 12 Charge. At this time, the switching element 26 in the chopper circuit 108 is kept off.

When the AC power supply 1 fails, a power failure detection circuit 2
3, the changeover switch 2 is switched to the battery 20 side via the battery switching element 21, and the battery switching element 21 and the reactor 3 are switched.
Is connected. At this time, the positive side capacitor 11 and the negative side capacitor 12 can be charged separately by the on / off operation of the switching element 26 and the battery switching element 21 in the chopper circuit 108. Note that the switching element 27 in the chopper circuit 108 is kept off.

First, the charging operation of the positive side capacitor 11 will be described. When the battery switching element 21 is turned on and the switching element 26 in the chopper circuit 108 is turned on, the path of the battery 20-the battery switching element 21-the reactor 3-the diode 4-the switching element 26-the battery 20 is energized. As a result, energy is stored in the reactor 3. Next, when the switching element 26 is turned off with the battery switching element 21 kept in the on state, the energy stored in the reactor 3 is converted into the reactor 3-diode 4-diode 28-capacitor 11-battery 20
-The battery 11 is discharged to the path of the battery switching element 21-the reactor 3, and the capacitor 11 is charged.

Next, charging of the negative capacitor 12 will be described. The switching element 26 in the chopper circuit 108 is turned on, and when the battery switching element 21 is turned on, energy is accumulated in the reactor 3 along the same path as described above. Next, when the battery switching element 21 is turned off while the switching element 26 is kept on, the energy accumulated in the reactor 3 is transferred to the reactor 3-diode 4-switching element 26-capacitor 12-diode 22-reactor 3. It is discharged to the path, and the capacitor 12 is charged.

By the above operation, capacitors 11 and 12 can be charged to a voltage higher than the voltage of battery 20. The voltages charged in the capacitors 11 and 12 are applied to the switching elements 13 and 14 of the inverter circuit 105 as in the case of the circuit of FIG.
Is converted into an AC voltage by the ON / OFF operation of the filter circuit, the harmonics are removed by the filter circuit 106, and the resultant is applied to the load 19 as a sine wave AC voltage.

During operation with the battery 20, as described above, the switching element 26 and the battery switching element 21 in the chopper circuit 108 are alternately turned on and off, and the positive side capacitor 11 and the negative side capacitor 1 are turned on.
2 can be charged individually, and even when the load 19 is unbalanced, the voltages of the positive-side capacitor 11 and the negative-side capacitor 12 can be controlled to desired values, respectively. Also does not cause output voltage imbalance or overvoltage trip.

Embodiment 4 FIG. FIG. 4 shows a fourth embodiment of the uninterruptible power supply according to the present invention. In this embodiment, an on / off switch 24 is used instead of the changeover switch 2 in the third embodiment shown in FIG.
A backflow prevention diode 25 is provided between the battery switching element 21 and the battery 20 in series with the battery switching element 21, and a connection point between the battery switching element 21 and the diode 22 is connected to the reactor 3 and the switch 24. Are connected to the connection point. In FIG. 4, components denoted by the same reference numerals as those in FIG. 3 perform the same operations, and a description thereof will be omitted.

In the circuit shown in FIG. 4, when the AC power supply 1 is in a normal state, the on / off switch 24 is turned on and the battery switching element 21 is turned off. In this state, the battery 20 enters a sleep state. When the AC power supply 1 loses power, the ON / OFF switch 24 is turned off by a command from the power failure detection circuit 23, and the AC power supply 1 is disconnected.
The other charging operations of the capacitors 11 and 12 are the same as in the first embodiment.

In the fourth embodiment, the backflow prevention diode 25 is provided in series with the battery switching element 21. Thus, the switch 25 is turned on instead of the changeover switch 2 of the first embodiment shown in FIG. Even if the off switch 24 is used, the positive side capacitor 11 and the negative side capacitor 12 can be charged alternately, and the switch portion can be configured at low cost.

Embodiment 5 FIG. FIG. 5 shows a fifth embodiment of the uninterruptible power supply according to the present invention. In the fifth embodiment, the switching element for battery 21 and the diode 22 in the first embodiment shown in FIG. 1 are removed, and a series circuit of a switching element 30 for charging a negative capacitor and a reactor (second reactor) 31 is used instead. Are connected to the positive side DC bus 51, in other words, the positive side terminal of the positive side capacitor 11 and the common line 50, and the interconnection point between the switching element 30 and the reactor 31 and the negative side DC bus 52, In this case, the diode 32 is provided between the negative terminal of the negative capacitor 12 and the negative terminal. The battery 20 is connected to a common line 50. In FIG. 5, components denoted by the same reference numerals as those in FIG. 1 perform the same operations, and a description thereof will be omitted.

Next, the operation of the fifth embodiment will be described. When the AC power supply 1 is in a normal state, the changeover switch 2 is switched to the AC power supply 1 side, and the capacitors 11 and 12 are individually charged by the same operation as in the first embodiment shown in FIG.

When the AC power supply 1 fails, a power failure detection circuit 2
According to the command of 3, the changeover switch 2 is switched to the battery 20 side, and the battery 20 and the reactor (first reactor) 3 are connected. In this embodiment, the positive side capacitor 11 is charged by the energy of the battery 20 by the on / off operation of the switching element 10 of the bidirectional switch 107, and the switching element 3
By the on / off operation of 0, the capacitor 12 on the negative side can be charged by the energy of the capacitor 11.

The charging operation of the positive side capacitor 11 is almost the same as that of the first embodiment shown in FIG. 1. When the switching element 10 of the bidirectional switch 107 is turned on, the battery 20-reactor 3-diode 7 Power is supplied to the path of the switching element 10, the diode 9, and the battery 20, and energy is stored in the reactor 3. Next, by turning off the switching element 10,
The energy stored in reactor 3 is reactor 3-
It is discharged to the path of the diode 4-the capacitor 11-the battery 20-the reactor 3, and the capacitor 11 is charged.

Next, charging of the negative side capacitor 12 will be described. When the switching element 30 for charging the negative-side capacitor is turned on, current flows through the path of the capacitor 11 -the switching element 30 -the reactor 31 -the capacitor 11 to accumulate energy in the reactor 31.
The switching element 30 is turned off, and the energy stored in the reactor 31 is transferred to the reactor 31-the capacitor 12.
Discharging into the path of the diode 32 to charge the capacitor 12;

By the above operation, capacitors 11 and 12 can be charged to a voltage higher than the voltage of battery 20. The voltages charged in the capacitors 11 and 12 are applied to the switching elements 13 and 14 of the inverter circuit 105 as in the case of the circuit of FIG.
Is converted into an AC voltage by the ON / OFF operation of the filter circuit, the harmonics are removed by the filter circuit 106, and the resultant is applied to the load 19 as a sine wave AC voltage.

During operation with the battery 20, as described above, the switching element 10 in the bidirectional switch 107 and the switching element 30 for charging the negative side capacitor are used.
To turn on / off the capacitor 11 on the positive side and the capacitor 12 on the negative side, respectively.
Even when 9 is unbalanced, it is possible to control the voltages of the positive-side capacitor 11 and the negative-side capacitor 12 to desired values, respectively, and to cause an unbalanced output voltage and an overvoltage trip even with an unbalanced load. There is no.

Further, in the fifth embodiment, since the negative side capacitor 12 is charged from the voltage of the positive side capacitor 11 having a higher voltage than that of the battery 20, the switching element 30 for charging the negative side capacitor is provided as shown in FIG. Therefore, a switching element having a smaller current capacity can be used than the battery switching element 21 of the first embodiment shown in FIG.

Embodiment 6 FIG. FIG. 6 shows a sixth embodiment of the uninterruptible power supply according to the present invention. In the sixth embodiment, the switching element for battery 21 and the diode 22 in the first embodiment shown in FIG. 1 are removed, and instead, a switching element 40 and a switching element 41 for charging a negative capacitor, and these switching elements 40, The diodes 42 and 43 and the reactor (second reactor) 4 connected in anti-parallel to each of
4 are provided.

The switching element 41 and the reactor 44 having the diode 43 connected in anti-parallel are connected in series and connected between the common line 50 and the negative DC bus 52 (the negative terminal of the negative capacitor 12). I have. The switching element 40 for charging the negative side capacitor in which the diode 42 is connected in anti-parallel is connected to an interconnection point between the reactor 44 and the switching element 41 and the diode 43 and the battery 20.
Connected to the positive terminal of

In such an uninterruptible power supply, the reactor 44, the switching element 41, and the diode 42 are usually provided for charging the battery 20, and can be realized by using them together. In FIG. 6, components denoted by the same reference numerals as those in FIG. 1 perform the same operations, and a description thereof will be omitted.

Next, the operation of the sixth embodiment will be described. When the AC power supply 1 is in the normal state, the changeover switch 2 is switched to the AC power supply 1 side, and the capacitors 11 and 12 are individually charged by the same operation as in the first embodiment shown in FIG. When the AC power supply 1 loses power, the changeover switch 2 is switched to the battery 20 side by a command from the power failure detection circuit 23, and the battery 20 and the reactor (first reactor) 3 are connected.

In the sixth embodiment, the bidirectional switch 107
The positive side capacitor 11 is charged by the on / off operation of the switching element 10 inside, and the on / off operation of the switching element 40 for charging the negative side capacitor is performed by
The capacitor 12 can be charged. At this time, the switching element 41 provided for charging the battery 20 is turned off.

The charging operation of the positive side capacitor 11 is shown in FIG.
When the switching element 10 in the bidirectional switch 107 is turned on, power is supplied to the path of the battery 20, the reactor 3, the diode 7, the switching element 10, the diode 9, and the battery 20. , The energy is stored in the reactor 3. Next, when the switching element 10 is turned off, the energy stored in the reactor 3 is converted into the reactor 3-the diode 4-the capacitor 11-the battery 20-the reactor 3
And the capacitor 11 is charged.

Next, charging of the negative side capacitor 12 will be described. When the switching element 40 for charging the negative-side capacitor is turned on, power is supplied to the path of the battery 20, the switching element 40, the reactor 44, and the battery 20, and energy is accumulated in the reactor 44. Next, by turning off the switching element 40 for charging the negative-side capacitor, the energy accumulated in the reactor 44 is reduced to the reactor 44 -the capacitor 12 -the diode 43.
And the capacitor 12 is charged.

By the above operation, capacitors 11 and 12 can be charged to a voltage higher than the voltage of battery 20. The voltages charged in the capacitors 11 and 12 are applied to the switching elements 13 and 14 of the inverter circuit 105 as in the case of the circuit of FIG.
Is converted into an AC voltage by the ON / OFF operation of the filter circuit, the harmonics are removed by the filter circuit 106, and the resultant is applied to the load 19 as a sine wave AC voltage.

During operation with the battery 20, as described above, the switching element 10 in the bidirectional switch 107 and the switching element 40 for charging the negative side capacitor are used.
To turn on / off the capacitor 11 on the positive side and the capacitor 12 on the negative side, respectively.
Even when 9 is unbalanced, it is possible to control the voltages of the positive-side capacitor 11 and the negative-side capacitor 12 to desired values, respectively, and to cause an unbalanced output voltage and an overvoltage trip even with an unbalanced load. There is no.

Further, in the sixth embodiment, the reactor 44 conventionally provided for charging the battery 20 can be used for charging the negative-side capacitor 12, so that the configuration can be made small and inexpensive.

In each of the embodiments, the filter circuit 106 is described as an example of an L-type filter circuit including the reactor 17 and the capacitor 18, but the filter circuit 106 is not limited to this.

[0073]

As can be understood from the above description, according to the uninterruptible power supply according to the present invention, when a power failure of the AC power supply is detected, the connection to the reactor is made from the AC power supply to the battery and the battery switching element. The positive side capacitor and the negative side capacitor are charged individually by the on / off operation of the battery switching element and the switching element in the chopper circuit, so that the load connected to the AC output Even in the case of positive / negative imbalance, it is possible to control the voltage of the positive and negative capacitors to the desired values, respectively, and to obtain an uninterruptible power supply with no output voltage imbalance or overvoltage trip even with an unbalanced load. This has the effect.

According to the uninterruptible power supply according to the next invention, the switching element in the chopper circuit is charged by the on / off operation of the switching element in the chopper circuit by turning on the switching element for the battery, and the switching element in the chopper circuit. And the negative side capacitor is charged by the on / off operation of the battery switching element, so that the positive side capacitor and the negative side capacitor can be charged separately, and the load connected to the AC output is positive or negative. Even in the case of unbalance, it is possible to control the voltage of the positive and negative capacitors to the desired values, respectively, and to obtain an uninterruptible power supply without unbalanced output voltage or overvoltage trip even under unbalanced load. effective.

According to the uninterruptible power supply according to the next invention, since the backflow prevention diode is connected in series with the battery switching element, switching to the series circuit of the AC power supply, the battery and the battery switching element is performed. Can be configured with a simple on / off switch, and the switch portion can be configured at low cost.

According to the uninterruptible power supply according to the next invention, when a power failure of the AC power supply is detected, the connection to the first reactor is switched from the AC power supply to the battery,
The on-off operation of the switching element for charging the negative side capacitor and the switching element in the chopper circuit separately charges the positive side capacitor and the negative side capacitor, so that the load connected to the AC output is positive or negative. Even in the case of unbalance, it is possible to control the voltage of the positive and negative capacitors to the desired values, respectively, and to obtain an uninterruptible power supply without unbalanced output voltage or overvoltage trip even under unbalanced load. effective.

According to the uninterruptible power supply according to the next invention, the positive side capacitor is charged by the energy of the battery by the on / off operation of the switching element in the chopper circuit, and the switching element for charging the negative side capacitor is turned on.・ The negative side capacitor is charged by the energy of the positive side capacitor in the off operation, so that the positive side capacitor and the negative side capacitor can be charged separately, and the load connected to the AC output is imbalanced. In this case, the voltage of the positive and negative capacitors can be controlled so as to be respectively desired values, and even in an unbalanced load, an uninterruptible power supply without output voltage unbalance or overvoltage trip can be obtained.
Moreover, since the negative-side capacitor is charged from the voltage of the positive-side capacitor having a higher voltage than the battery, a switching element having a small current capacity can be used as a switching element for charging the negative-side capacitor, and the switching element can be configured at a low cost. effective.

According to the uninterruptible power supply according to the next invention, when a power failure of the AC power supply is detected, the connection to the first reactor is switched from the AC power supply to the battery, and the switching element for charging the negative capacitor and the chopper are connected. Since the positive and negative capacitors are charged by the on / off operation of the switching elements in the circuit, the positive and negative capacitors can be charged separately,
Even if the load connected to the AC output is unbalanced, the voltage on the positive and negative capacitors can be controlled to the desired values, respectively. There is an effect that an uninterruptible power supply device without any trouble can be obtained.

The uninterruptible power supply according to the next invention charges the positive side capacitor with the energy of the battery by the on / off operation of the switching element in the chopper circuit, and turns on / off the switching element for charging the negative side capacitor. Since the negative side capacitor is charged by the energy of the positive side capacitor in the OFF operation, the positive side capacitor and the negative side capacitor can be charged separately, and the load connected to the AC output is unbalanced. In this case, the voltage of the positive and negative capacitors can be controlled so as to be respectively desired values, and even in an unbalanced load, an uninterruptible power supply without output voltage unbalance or overvoltage trip can be obtained.
Moreover, since the negative-side capacitor is charged from the voltage of the positive-side capacitor having a higher voltage than the battery, a switching element having a small current capacity can be used as a switching element for charging the negative-side capacitor, and the switching element can be configured at a low cost. effective.

According to the uninterruptible power supply according to the next invention, since the switching elements in the chopper circuit are bidirectional switches, the number of switching elements can be reduced, and there is an effect that the configuration can be made compact and inexpensive.

In the uninterruptible power supply according to the next invention, when the AC power supply is normal, the battery is charged by discharging the energy stored in the second reactor. This can be used in combination with the charging of the capacitor on the side, and has the effect that the device can be made compact and inexpensive.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing Embodiment 1 of an uninterruptible power supply according to the present invention.

FIG. 2 is a circuit diagram showing Embodiment 2 of an uninterruptible power supply according to the present invention.

FIG. 3 is a circuit diagram showing Embodiment 3 of an uninterruptible power supply according to the present invention.

FIG. 4 is a circuit diagram showing Embodiment 4 of an uninterruptible power supply according to the present invention.

FIG. 5 is a circuit diagram showing Embodiment 5 of the uninterruptible power supply according to the present invention.

FIG. 6 is a circuit diagram showing Embodiment 6 of the uninterruptible power supply according to the present invention.

FIG. 7 is a circuit diagram showing a conventional uninterruptible power supply.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 AC power supply, 2 changeover switch, 3 reactor (first reactor), 4 to 9 diode, 10 battery switching element, 11 positive side capacitor, 1
2 Negative side capacitor, 13, 14 Switching element, 15, 16 diode, 17 reactor, 18
Capacitor, 19 load, 20 battery, 21 switching element, 22 diode, 23 power failure detection circuit, 24 on / off switch, 25 backflow prevention diode, 26, 27 switching element, 28, 29 diode, 30 for negative side capacitor charging Switching element, 31 reactor (second reactor), 32
Diode, 40 switching element for charging the negative capacitor, 41 switching element, 42, 43 diode, 44 reactor (second reactor), 50 common line, 51 positive DC bus, 52 negative DC bus,
100, 101 switching element, 102, 103
Diode, 104 chopper circuit, 105 inverter circuit, 106 filter circuit, 107 bidirectional switch, 108 chopper circuit.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Taro Ando 2-3-2 Marunouchi, Chiyoda-ku, Tokyo F-term (reference) in Mitsui Electric Co., Ltd. 5G015 FA10 GA03 GA07 HA03 HA04 JA05 JA06 JA07 JA23 JA32 JA34 JA53 JA62 5H007 BB05 CA01 CB12 CC01 DA06 DB01 DC05 FA01 FA02 FA12 FA17

Claims (9)

[Claims] 1. A common capacitor in which one end of each of an AC power supply and an AC output and an interconnection point of the positive side capacitor and the negative side capacitor are connected. And a line, connected to the other end of the AC power supply via a reactor, obtains a positive DC voltage from a positive half cycle of the voltage of the AC power supply, charges the capacitor on the positive side, and turns negative from a negative half cycle. A chopper circuit that obtains a DC voltage and charges the negative-side capacitor; an inverter circuit that reconverts the positive and negative DC voltages charged in the positive-side capacitor and the negative-side capacitor into an AC voltage; A series circuit of a battery and a battery switching element connected to the AC power supply, and when a power failure of the AC power supply is detected, the connection to the reactor is switched to the AC power supply. From the power supply to the series circuit,
An uninterruptible power supply device wherein the positive side capacitor and the negative side capacitor are individually charged by on / off operations of the battery switching element and the switching element in the chopper circuit. 2. The battery switching element is turned on, the positive side capacitor is charged by the on / off operation of the switching element in the chopper circuit, and the switching element in the chopper circuit is turned on. The uninterruptible power supply according to claim 1, wherein the negative-side capacitor is charged by an on / off operation of the switching element. 3. The uninterruptible power supply according to claim 1, wherein a backflow prevention diode is connected in series to the battery switching element. 4. A common capacitor in which a positive-side capacitor and a negative-side capacitor connected in series, one end of an AC power supply and an AC output, and an interconnection point of the positive-side capacitor and the negative-side capacitor are connected. A first reactor connected to the other end of the AC power supply via a first reactor to obtain a positive DC voltage from a positive half cycle of the voltage of the AC power supply to charge the positive-side capacitor; A chopper circuit that obtains a negative DC voltage from a cycle and charges the negative-side capacitor; and an inverter circuit that reconverts the positive and negative DC voltages charged in the positive-side capacitor and the negative-side capacitor into an AC voltage. A series circuit of a switching element for charging a negative capacitor connected between a positive terminal of the positive capacitor and the common line, and a second reactor; A diode connected between an interconnection point of the power switching element and the second reactor and a negative terminal of the negative capacitor, and a battery connected to the common line, When a power failure of the AC power supply is detected, the connection to the first reactor is switched from the AC power supply to the battery, and the on / off operation of the switching element for charging the negative capacitor and the switching element in the chopper circuit is performed. Wherein the positive-side capacitor and the negative-side capacitor are charged separately. 5. The on-off operation of a switching element in the chopper circuit charges the positive-side capacitor with energy of the battery, and the on-off operation of a switching element for charging the negative-side capacitor causes the charging of the negative-side capacitor. The uninterruptible power supply according to claim 4, wherein the negative-side capacitor is charged by the energy of the positive-side capacitor. 6. A common capacitor in which a positive-side capacitor and a negative-side capacitor connected in series, one end of each of an AC power supply and an AC output, and an interconnection point of the positive-side capacitor and the negative-side capacitor are connected. A first reactor connected to the other end of the AC power supply via a first reactor to obtain a positive DC voltage from a positive half cycle of the voltage of the AC power supply to charge the positive-side capacitor; A chopper circuit that obtains a negative DC voltage from a cycle and charges the negative-side capacitor; and an inverter circuit that reconverts the positive and negative DC voltages charged in the positive-side capacitor and the negative-side capacitor into an AC voltage. A battery connected to the common line; a series circuit of a second reactor and a diode connected between the common line and a negative terminal of the negative capacitor; A switching element for charging a negative-side capacitor connected between an interconnection point between an actuator and the diode and a positive-side terminal of the battery, wherein when a power failure of the AC power supply is detected, the first The connection to the reactor is switched from the AC power supply to the battery, and the on-off operation of the switching element for charging the negative-side capacitor and the switching element in the chopper circuit causes the positive-side capacitor and the negative-side capacitor to switch. Uninterruptible power supply, wherein the power supply is charged individually. 7. The on-off operation of a switching element in the chopper circuit charges the positive-side capacitor with the energy of the battery, and the on-off operation of the switching element for charging the negative-side capacitor causes the battery to charge. The uninterruptible power supply according to claim 6, wherein the negative side capacitor is charged by the energy of the positive side capacitor. 8. A switching element in the chopper circuit is a bidirectional switch.
The uninterruptible power supply according to any one of the above. 9. The uninterruptible power supply according to claim 6, wherein when the AC power supply is normal, the battery is charged by discharging energy stored in the second reactor.