JP2001197685A - Uninterruptible power supply system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase operational reliability of an uninterruptible power supply system which supplies power to a load, from power system such as a commercial power supply under normal conditions and supplies power to the load from an inverter system having a battery, when the power system is in an abnormal condition. SOLUTION: When there is a temporary voltage drop in the power supply system 1, voltage drop is compensated by power supply equipment 7. Thereby the charging and discharging frequency of a battery owned by power supply equipment 2 as a power storage means 3 can be reduced, extending the service life of the battery and eventually extending the service life of the uninterruptible power supply system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally comprises a power supply system such as a commercial power supply for supplying a load to a load. The present invention relates to an uninterruptible power supply system for supplying power from a power supply device to a load.

[0002]

2. Description of the Related Art FIG. 13 is a configuration diagram showing a conventional form of this type of uninterruptible power supply system, wherein 1 is a power system such as a commercial power supply, 2 is a power supply device having a power storage means 3, and 4 is an illustration. Reference numeral 6 denotes a circuit breaker inserted between the power system 1 and the power receiving point 5.

FIG. 14 is a circuit diagram showing a specific conventional example of the uninterruptible power supply system shown in FIG. 13, in which an inverter device 20 described later is used as the power supply device 2 and a battery 30 is used as the power storage means 3. Have.

FIG. 15 is a detailed circuit configuration diagram of the inverter device 20 shown in FIG. 14, which is an example of a case where the power system 1 has a three-phase output. As shown in FIG. An inverter main circuit 21 having a phase bridge connection, a capacitor 22 connected to the DC side of the inverter main circuit 21, and an inverter control circuit (not shown) are provided.

FIG. 16 is a detailed circuit configuration diagram of the inverter device 20 shown in FIG. 14, which is different from the circuit configuration shown in FIG. 15, and is an example when the power system 1 has a single-phase output. As described above, the inverter main circuit 23 in which the anti-parallel circuit of the IGBT and the diode is formed in a single-phase bridge connection,
A capacitor 22 connected to the DC side of the inverter main circuit 23 and an inverter control circuit (not shown) are provided.

FIG. 17 shows an example of a chopper device 40 inserted when the voltage between both ends of the capacitor 22 shown in FIGS. 15 and 16 and the terminal voltage of the battery 30 shown in FIG. 14 need to be matched. FIG. 3 is a circuit configuration diagram showing

In FIG. 17, reference numerals 41 and 42 denote, for example, IG
An anti-parallel circuit of a BT and a diode, 43 is a reactor, and the chopper device 40 can bidirectionally transmit and receive electric power by switching modes of the anti-parallel circuits 41 and 42, respectively.

The operation of the uninterruptible power supply system shown in FIG. 14 will be described below.

Normally, the circuit breaker 6 is closed and the power system 1
, The battery 30 is charged by the inverter device 20 while supplying power to the load 4.

When the power system 1 is abnormal, the monitoring circuit (not shown) detects the abnormality and opens the circuit breaker 6, while the inverter device 20 using the normally charged battery 30 as a DC power source supplies the load 4 to the load 4. Power.

[0011]

In the conventional uninterruptible system shown in FIG. 14, the equipment forming the load 4 includes:
When the voltage at the power receiving point 5 falls below the allowable lower limit, it often does not function properly. , The power system 1 is determined to be abnormal.

However, when the value is below the allowable lower limit,
Even when a mere temporary voltage drop occurs in the power system 1, power is supplied from the inverter device 20 to the load 4, and
Each time, the battery 30 is in a discharged state. As a result, the frequency of charging and discharging of the battery 30 increases. For example, in the case of a lead-acid battery as the battery 30, the frequent charging and discharging shortens the life, and the life of the entire uninterruptible power supply system also decreases. is there.

The original purpose of installing the uninterruptible power supply system shown in FIG. 14 is to back up the power system 1, and therefore, it is desirable that the number of discharges of the battery 30 be reduced as much as possible and that the battery 30 is always fully charged. .

An object of the present invention is to solve the above-mentioned problems and to provide an uninterruptible power supply system which is closer to the original installation purpose described above.

[0015]

According to a first aspect of the present invention, a first power supply device having power storage means is connected in parallel to a power system, and a power receiving point between the first power supply device and the power system is provided at a power receiving point. An uninterruptible power supply that normally supplies power to the load from a power system for a connected load, and supplies power from the first power supply device to the load while the power system is open when the power system is abnormal. In the system, an uninterruptible power supply system is characterized in that a second power supply is inserted in series between a power system and the power receiving point.

According to a second aspect of the present invention, in the uninterruptible power supply system according to the first aspect, the second power supply device includes power storage means.

According to a third aspect of the present invention, in the uninterruptible power supply system according to the first aspect of the present invention, power interchange means is added between the first power supply and the second power supply. According to the present invention, as described later, by providing the second power supply device with a function of compensating for a temporary voltage drop in a power system, an uninterruptible power supply system that reduces the life of the power storage unit is reduced. Can be provided.

[0018]

FIG. 1 is a block diagram showing an uninterruptible power supply system according to a first embodiment of the present invention.
1 having the same functions as those of the conventional configuration shown in FIG.

That is, the configuration shown in FIG. 1 is different from the configuration shown in FIG. 13 in that a power supply device 7 as a second power supply device is inserted between a power receiving point 5 and a circuit breaker 6 in series. In addition, the power supply device 2 is a first power supply device.

FIG. 2 is a configuration diagram of an uninterruptible power supply system according to a second embodiment of the present invention, in which components having the same functions as those of the first embodiment shown in FIG. It is attached.

That is, the configuration shown in FIG. 2 is different from the configuration shown in FIG. 1 in that the power supply device 7 has the power storage means 8.

FIG. 3 is a block diagram of an uninterruptible power supply system according to a third embodiment of the present invention, in which components having the same functions as those of the first embodiment shown in FIG. It is attached.

That is, the difference between the configuration shown in FIG. 3 and the configuration shown in FIG. 1 is that a power interchanger 9 is provided between the power supply 2 and the power supply 7 so that the power of the power storage This is to be flexible.

FIG. 4 is a circuit configuration diagram of the uninterruptible power supply system showing the first embodiment of the present invention, and is a specific circuit configuration diagram of the uninterruptible power supply system shown in FIG.

That is, an inverter device 70 and a transformer 71 are provided as the power supply device 7 shown in FIG. 1. The detailed circuit configuration of the inverter device 70 is shown in FIG.
6 is similar to the circuit configuration of FIG.

The operation of the uninterruptible power supply system shown in FIG. 4 will be described below.

Normally, the circuit breaker 6 is closed and the power system 1
The battery 30 is charged by the inverter device 20 while power is supplied to the load 4 via the secondary winding of the transformer 71 from the power supply.

At this time, the inverter device 20 is connected to the battery 30
Is controlled so as to maintain a fully charged state. Therefore, the internal loss of the inverter device 20 and the battery 30
And the electric power that compensates for the natural discharge of the battery.

In addition, when a slight abnormality occurs in the power system 1, for example, when a temporary voltage drop or a momentary interruption occurs, the inverter device 70 can correct the reduced amount via the transformer 71 in advance. Within this range, the reduction at this time is compensated.

The above-mentioned compensation operation will be described below with reference to the vector diagram shown in FIG.

In FIG. 5, the voltage at the receiving point 5 is V _L (normal value ≒ rated value), the current from the power system 1 is I _L , the voltage of the power system 1 is V _S, and the voltage of the transformer 71 is Assuming that the voltage between both ends of the next winding is V _I , each of them has a vector relationship as shown, and the voltage _VL of the receiving point 5 corrected by the inverter device 70 via the transformer 71 is represented by the power factor of the load 4 as shown in FIG. Move on an arc (dotted line).

[0032] That is, the inverter device 70, 15 or so can only supply reactive power to the circuit configuration shown in FIG. 16, current to I _L, quadrature phase of the voltage as shown (voltage V _I Is multiplied by the transformation ratio of the transformer 71).

Further, when the power system 1 is in a serious abnormality, that is, when the voltage of the power system 1 is reduced to a voltage that cannot be compensated by the inverter device 70, the monitoring circuit (not shown) detects this and opens the circuit breaker 6. Then, the load 4 is supplied from the inverter device 20 using the battery 30 charged at the normal time as a DC power source.

FIG. 6 is a circuit configuration diagram of an uninterruptible power supply system showing a second embodiment of the present invention, and is a specific circuit configuration diagram of the uninterruptible power supply system shown in FIG.

That is, the power supply device 7 shown in FIG. 2 includes an inverter device 70 and a transformer 71, and the inverter device 70 includes a battery 80 as power storage means 8.

The operation of the uninterruptible power supply system shown in FIG. 6 will be described below.

Normally, the circuit breaker 6 is closed and the power system 1
, The battery 30 is charged by the inverter device 20 while the power is supplied to the load 4 via the secondary winding of the transformer 71, and the battery 80 is similarly charged by the inverter device 70.

At this time, the inverter device 20 is
Is controlled to maintain the full charge state, and similarly, the inverter device 70 controls the battery 80 to maintain the full charge state. Therefore, the internal loss of the inverter device 20 from the power supply device 1 and the battery 30 And the electric power that compensates for the internal loss of the inverter device 70 and the natural discharge of the battery 80 are supplied.

In addition, when a slight abnormality occurs in the power system 1, for example, when a temporary voltage drop or a momentary interruption occurs, the inverter device 70 can correct the drop through the transformer 71. Within this range, the reduction at this time is compensated.

The above-described compensation operation will be described below with reference to the vector diagram shown in FIG.

In FIG. 7, the voltage at the receiving point 5 is V _L (normal value ≒ rated value), the current from the power system 1 is I _L , the voltage of the power system 1 is V _S, and the voltage of the transformer 71 is Assuming that the voltages at both ends of the next winding are V _I , they have a vector relationship as shown, and the voltage _{VL at} the receiving point 5 moves on the arc (dotted line) shown by the power factor of the load 4.

That is, since the inverter device 70 has the battery 80 on its DC side, it can supply both active power and reactive power. Therefore, as shown in the figure, the inverter device 70 has the same voltage as the voltage V _S of the power supply system 1. Phase voltage (voltage V
_I multiplied by the transformation ratio of the transformer 71). That is, the voltage output from the inverter device 7 can be compensated with a smaller value than the circuit configuration shown in FIG.

Further, when the power system 1 is in a serious abnormality, that is, when the voltage of the power system 1 is reduced to a voltage that cannot be compensated by the inverter device 70, this is detected by a monitoring circuit (not shown) and the circuit breaker 6 is opened. Then, the load 4 is supplied from the inverter device 20 using the battery 30 charged at the normal time as a DC power source.

FIG. 8 is a circuit configuration diagram of an uninterruptible power supply system showing a third embodiment of the present invention, and is a specific circuit configuration diagram of the uninterruptible power supply system shown in FIG.

That is, as the power supply device 7 shown in FIG. 3, an inverter device 70 and a transformer 71 are provided, and between the inverter device 20 and the inverter device 70, the power interchange means 9 is provided.
Power exchange means 9a and 9b, and the power exchange means 9a and 9b allow the electric power of the battery 30 to be exchanged between both.

The operation of the uninterruptible power supply system shown in FIG. 8 is the same as that of the uninterruptible power supply system shown in FIG. 70 can perform control to maintain full charge.

FIG. 9 is a circuit diagram of an uninterruptible power supply system according to a fourth embodiment of the present invention. FIG. 9 is a specific circuit diagram of the uninterruptible power supply system shown in FIG. Although the installation position of the circuit breaker 6 is changed as a point different from the circuit of the first embodiment, the operation of the entire uninterruptible power supply system is the same.

In the circuit configuration shown in FIG. 9, the transformer 71 may be omitted, and the output of the inverter device 70 may be directly inserted into the path between the power system 1 and the load 4.

FIG. 10 is a circuit diagram of an uninterruptible power supply system according to a fifth embodiment of the present invention. FIG. 10 is a specific circuit diagram of the uninterruptible power supply system shown in FIG. The difference from the circuit of the second embodiment is that the installation position of the circuit breaker 6 is changed, but the operation of the entire uninterruptible power supply system is the same.

FIG. 11 is a circuit configuration diagram of an uninterruptible power supply system according to a sixth embodiment of the present invention. FIG. 8 is a specific circuit configuration diagram of the uninterruptible power supply system shown in FIG. Although the installation position of the circuit breaker 6 is changed as a point different from the circuit of the first embodiment, the operation of the entire uninterruptible power supply system is the same.

FIG. 12 is a circuit configuration diagram of an uninterruptible power supply system according to a seventh embodiment of the present invention. FIG. 12 is a specific circuit configuration diagram of the uninterruptible power supply system shown in FIG. The difference from the circuit of the first embodiment is that the output of the inverter device 72 is inserted in series between the power system 1 and the receiving point 5, but the operation of the entire uninterruptible power supply system is the same.

In each of the embodiments shown in FIGS. 6, 8 to 11, the transformer 71 can be omitted as in the configuration of the embodiment shown in FIG.

Further, in the description of the above-described embodiment, the example of a general battery such as a lead battery is shown as the power storage means. In addition, a flywheel, a superconducting power storage device (SM)
ES).

[0054]

According to the present invention, by providing the second power supply with a function of compensating for a temporary voltage drop in the power system, the frequency of supplying power from the first power supply to the load is reduced as much as possible. It is possible to provide an uninterruptible power supply system in which the life of the power storage means is less reduced.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an uninterruptible power supply system according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of an uninterruptible power supply system according to a second embodiment of the present invention;

FIG. 3 is a configuration diagram of an uninterruptible power supply system showing a third embodiment of the present invention;

FIG. 4 is a circuit configuration diagram of an uninterruptible power supply system according to a first embodiment of the present invention;

5 is a vector diagram illustrating the operation of FIG.

FIG. 6 is a circuit configuration diagram of an uninterruptible power supply system according to a second embodiment of the present invention.

7 is a vector diagram illustrating the operation of FIG.

FIG. 8 is a circuit configuration diagram of an uninterruptible power supply system showing a third embodiment of the present invention.

FIG. 9 is a circuit configuration diagram of an uninterruptible power supply system according to a fourth embodiment of the present invention.

FIG. 10 is a circuit configuration diagram of an uninterruptible power supply system according to a fifth embodiment of the present invention.

FIG. 11 is a circuit diagram of an uninterruptible power supply system according to a sixth embodiment of the present invention.

FIG. 12 is a circuit configuration diagram of an uninterruptible power supply system according to a seventh embodiment of the present invention.

FIG. 13 is a configuration diagram of an uninterruptible power supply system showing a conventional mode.

FIG. 14 is a circuit configuration diagram of an uninterruptible power supply system showing a conventional example.

FIG. 15 is a circuit configuration diagram of an inverter device.

FIG. 16 is a circuit configuration diagram of an inverter device.

FIG. 17 is a circuit diagram of a chopper device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Power system, 2 ... Power supply device, 3 ... Power storage means, 4 ...
Load 5, power receiving point, 6 circuit breaker, 7 power supply device, 8 power storage means, 9, 9a, 9b power exchange means, 20 inverter device, 21, 23 inverter main circuit, 22
Condenser, 30 ... battery, 40 ... chopper device, 41,
42: anti-parallel circuit, 43: reactor, 70, 72: inverter device, 71: transformer, 80: battery.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H02M 7/48 H02M 7/48 NRF Term (Reference) 5G015 FA08 GA04 GA06 GA07 HA04 HA15 JA02 JA05 JA24 JA32 JA34 JA53 JA55 5G066 AA04 AA08 AD01 AE11 AE14 BA03 CA09 DA04 DA07 FA07 FB13 HA06 HB03 HB05 HB11 JA02 JB03 LA08 5H007 AA06 BB05 CA01 CB05 CB17 CC32 DA04

Claims (3)

[Claims] A first power supply device having power storage means is connected in parallel to a power system, and a load connected to a power receiving point between the first power supply device and the power system is normally connected to a load. In an uninterruptible power supply system for supplying power from the power system to the load and opening the power system side when the power system is abnormal, and supplying power from the first power supply device to the load, the power system and the power receiving point An uninterruptible power supply system in which a second power supply is inserted in series. 2. The uninterruptible power supply system according to claim 1, wherein the second power supply device includes a power storage unit. 3. The uninterruptible power supply system according to claim 1, wherein a power interchange means is added between the first power supply device and the second power supply device.