JP2000287458A - Power supply system and power supply method - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To appropriately supply power to a load side. SOLUTION: When an auxiliary transformer 2 is connected in series to an output side of a circuit breaker 1 and a second inverter 11 that varies a voltage applied to the auxiliary transformer 2, power saving to a load side is performed. The on / off operation of the second inverter 11 is controlled by the control device 10 so that the auxiliary transformer 2
When the first voltage is applied to the power supply and the voltage of the power to the load side is compensated, the control device 10 controls the on / off operation of the second inverter 11, and the auxiliary transformer 2 supplies the first voltage to the auxiliary transformer 2. A second voltage whose phase is inverted is applied.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a power supply system and a power supply method suitable for power supply.

[0002]

2. Description of the Related Art Conventionally, power from a commercial power supply is supplied to a load side by a power supply system having a backup device (battery).

When the supply of power from the commercial power supply is cut off, for example, during a power outage, the DC power from the backup device is converted into AC power by the inverter of the power supply system and supplied to the load side. ing.

[0004]

In the above-described conventional power supply system, power from a commercial power supply is directly supplied to a load.
A such as voltage drop or voltage rise according to the demand condition on the load side
It is impossible to provide a VR function.

[0005] In addition, smoothing of electric power used, effective use of electric power at night, and scheduled operation thereof are also impossible.

Furthermore, it is impossible to prevent a momentary power failure on the load side when the supply of power from the commercial power supply is cut off.

The present invention has been made to solve the above problems, and has as its object to provide a power supply system and a power supply method capable of appropriately supplying power to a load side.

[0008]

In order to achieve the above object, a power supply system according to the present invention comprises a first commercial power supply.
And an auxiliary transformer connected in series to the output side of the circuit breaker, and a second power supply provided on the output side of the auxiliary transformer and supplying power from the commercial power supply to the load side. A second supply line, a second inverter for varying a voltage applied to the auxiliary transformer,
A control device for controlling the on / off operation of the inverter, and when saving power to the load side, the on / off operation of the second inverter is controlled by the control device. When the first voltage is applied and the voltage of the power to the load side is compensated,
On / off operation of the second inverter is controlled by the control device, and a second voltage obtained by inverting the phase of the first voltage is applied to the auxiliary transformer.

A first inverter and a battery are connected in series to the output side of the auxiliary transformer, and the control device controls the driving of the first and second inverters to control the load side in three modes. May be supplied with power.

[0010] Of the three modes, the first mode is to drive and control only the second inverter.
The power from the commercial power supply is supplied to the load side, and the second mode controls the drive of the first inverter and the second inverter, so that the power from the commercial power supply and the power from the battery are And a third mode for driving the first inverter and the second inverter to supply electric power for charging the battery to the load side of the commercial power supply. The power supplied from the power may be supplied.

When the supply of electric power from the commercial power supply to the load side is interrupted due to a power failure or the like, the control device drives and controls the first inverter, and converts the DC power from the battery into the first electric power. Converted to AC by inverter,
You may make it supply to the said load side.

A power supply method according to the present invention includes a first step of connecting an auxiliary transformer in series with an output side of a circuit breaker provided with a first supply line of a commercial power supply, and a step of providing an auxiliary transformer on an output side of the auxiliary transformer. A second step of supplying power from the commercial power supply to the load side via the second supply line provided;
When performing a third step of varying the voltage applied to the auxiliary transformer with a second inverter, and when saving power to the load side, controlling the on / off operation of the second inverter and controlling the auxiliary transformer A fourth step of applying a first voltage, and controlling the on / off operation of the second inverter when compensating for the voltage of power to the load side;
A fifth step of applying a second voltage obtained by inverting the phase of the first voltage to the auxiliary transformer.

In the fourth and fifth steps, a first battery connected in series with a battery on the output side of the auxiliary transformer is provided.
And the second inverter are controlled in three modes to control power supply to the load side.
May be included.

[0014] The sixth step includes a step of controlling in a first mode in which power from the commercial power supply is supplied to a load side by controlling the drive of only the second inverter; Controlling the inverter and the second inverter in a second mode in which the power from the commercial power supply and the power from the battery are supplied to the load side by driving and controlling the first inverter and the second inverter. And controlling the load side by a third mode of supplying power obtained by subtracting power for charging the battery from power of the commercial power supply to the load side.

In the sixth step, when power supply from the commercial power supply to the load side is cut off due to a power failure or the like,
The method may include a step of driving and controlling the first inverter, converting DC power from the battery into AC by the first inverter, and supplying the alternating current to the load side.

The power supply system and the power supply method configured as described above include an auxiliary transformer connected in series to the output side of the circuit breaker, and a second inverter that varies a voltage applied to the auxiliary transformer. When power saving to the load side is performed, the control device controls the ON / OFF operation of the second inverter, applies the first voltage to the auxiliary transformer, and compensates for the power voltage to the load side. The control device controls the on / off operation of the second inverter, and applies the second voltage with the phase of the first voltage inverted to the auxiliary transformer.

[0017]

Embodiments of the present invention will be described below.

(First Embodiment) FIG. 1 is a circuit diagram showing a first embodiment of a power supply system according to the present invention, and FIG.
FIG. 2 is a waveform diagram for explaining the operation of the power supply system in FIG. 1.

A supply line A as a first supply line of the power supply system shown in FIG. 1 includes a circuit breaker 1, an auxiliary transformer 2, an AC switch 3, a reactor 4, an electromagnetic contactor 5, an AC filter 6, and a first filter. Are connected in series.

A battery 9 is connected to the first inverter 7 via an electromagnetic contactor 8.

A second inverter 11 for controlling reactance is connected to the auxiliary transformer 2. First inverter 7 and second inverter 11
The on / off operation is controlled by the control device 10.

The output side of the reactor 4 is connected to a supply line B as a second supply line for outputting an alternating current to the load side. A supply line C for directly supplying alternating current to the load side is connected to the input side of the circuit breaker 1. An electromagnetic contactor 12 is provided on the supply line C.

Next, the operation of the power supply system having such a configuration will be described with reference to FIG.

First, when the AVR function such as voltage drop or voltage rise in accordance with the demand state on the load side is not operated, the second inverter 11 in FIG. 1 is forcibly short-circuited. The electromagnetic contactor 12 is turned on when any of the devices 1 to 11 fails, and when a failure occurs, alternating current from a commercial power supply is directly supplied to the load.

At this time, the AC waveform has a sine curve as shown in FIG.

Next, when saving power to the load side,
The electromagnetic contactor 12 in FIG. 1 is turned off. At this time, the ON / OFF operation of the second inverter 11 is controlled by the control device 10. By the ON / OFF operation of the second inverter 11, the first voltage applied to the auxiliary transformer 2 has a waveform shown by a dashed line e in FIG. 2B.

Thus, the voltage supplied to the load side via the supply line B in FIG. 1 has a waveform indicated by a solid line f in FIG. 2B. Incidentally, the dashed line d in FIG. 2B is the waveform of the commercial power supply.

Next, when compensating the voltage of the electric power to the load side, the control device 10 controls the ON / OFF operation of the second inverter 11. In this case, as shown by a broken line e in FIG. 2C, the phase of the second voltage applied to the auxiliary transformer 2 is inverted with respect to FIG. 2B.

As a result, the voltage supplied to the load side via the supply line B in FIG. 1 has a waveform indicated by a solid line f in FIG. 2C.

As described above, in the first embodiment, the auxiliary transformer 2 connected in series to the output side of the circuit breaker 1 and the second inverter 11 that varies the voltage applied to the auxiliary transformer 2 are provided. When power saving to the load side is performed, the control device 10 controls the on / off operation of the second inverter 11 to apply the first voltage to the auxiliary transformer 2 and to reduce the power voltage to the load side. In the case of compensation, the control device 10 controls the on / off operation of the second inverter 11 and applies the second voltage with the phase of the first voltage inverted to the auxiliary transformer 2. The power supply to the side can be appropriately performed.

(Second Embodiment) FIG. 3 is a circuit diagram showing a power supply system according to a second embodiment of the present invention.
FIG. 4 is a diagram for explaining the operation of the power supply system in FIG. 3. In the drawings described below, the same parts as those in FIG. 1 are denoted by the same reference numerals, and redundant description is omitted.

In the second embodiment, the power consumption is smoothed, the nighttime power is effectively used, and the scheduled operation is performed.

That is, the control device 10 operates the first inverter 7 and the second inverter 11 in three modes.

In the first mode, the second inverter 11
By driving only the power, electric power from the commercial power supply is supplied to the load side.

In the second mode, by driving the first inverter 7 and the second inverter 11, electric power from the commercial power supply and electric power from the battery 9 are supplied to the load side.

In the third mode, by driving the first inverter 7 and the second inverter 11,-power is supplied to the load side. Thereby, the battery 9
Is charged with electric power.

Next, the operation of the power supply system having such a configuration will be described.

First, it is assumed that power is supplied to the load in a state as shown in FIG.

At this time, as shown in FIG. 4B, in the period of g, the driving of the first inverter 7 and the second inverter 11 is controlled in the third mode. As a result,-power is supplied to the load side, and the battery 9 is charged with power.

In the period h, the first inverter 7 and the second inverter 11 are driven and controlled in the second mode. Thereby, the electric power from the commercial power supply and the electric power from the battery 9 are supplied to the load side.

Further, during the period i, the first inverter 7 and the second inverter 11 are driven and controlled by the third mode. As a result,-power is supplied to the load side, and the battery 9 is charged with power.

As described above, in the second embodiment, the first
The first mode in which electric power from the commercial power supply is supplied to the load side by driving and controlling the inverter 7 and the second inverter 11, and the electric power from the commercial power supply and the electric power from the battery 9 are supplied to the load side. A second mode for supplying power to the load side can be taken.

As a result, the power storage in the battery 9 and the peak cut operation can be scheduled and operated.
Since the power can be effectively used, the efficiency of power consumption can be improved.

(Third Embodiment) FIG. 5 is a circuit diagram showing a power supply system according to a third embodiment of the present invention.

In the third embodiment, an instantaneous interruption to the load side when the supply of power from the commercial power supply is cut off is prevented.

That is, normally, as shown in the figure, the electric power from the commercial power supply is supplied to the load side.

When power supply from the commercial power supply to the load side is cut off due to a power failure or the like, the drive of the first inverter 7 is controlled by the control device 10 and the DC power from the battery 9 is reduced to the first power. The power is converted into AC by the inverter 7 and is supplied to the load side.

As described above, in the third embodiment, when the power supply from the commercial power supply to the load side is cut off due to a power failure or the like, the control device 10 controls the driving of the first inverter 7. Since the power obtained by converting the DC power from the battery 9 into AC power is supplied to the load side, it is possible to prevent a momentary power failure on the load side due to power failure or the like.

Also, at the time of a power failure, the response delay of the first inverter can be guaranteed by the energy discharge of the reactor 4, so that the instantaneous power failure can be more reliably prevented.

[0050]

As described above, according to the present invention,
An auxiliary transformer connected in series to the output side of the circuit breaker, and a second inverter that varies the applied voltage to the auxiliary transformer, and when power saving to the load side is performed, the control device controls the second inverter. When controlling the on / off operation and applying the first voltage to the auxiliary transformer and compensating the voltage of the power to the load side, the control device controls the on / off operation of the second inverter, and Is applied with the second voltage obtained by inverting the phase of the first voltage, power can be appropriately supplied to the load side.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a first embodiment of a power supply system of the present invention.

FIG. 2 is a waveform chart for explaining an operation of the power supply system of FIG. 1;

FIG. 3 is a circuit diagram showing a second embodiment of the power supply system of the present invention.

FIG. 4 is a diagram for explaining an operation of the power supply system of FIG. 3;

FIG. 5 is a circuit diagram showing a third embodiment of the power supply system of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Breaker 2 Auxiliary transformer 3 AC switch 4 Reactor 5 Electromagnetic contactor 6 AC filter 7 First inverter 8 Electromagnetic contactor 9 Battery 10 Controller 11 Second inverter 12 Electromagnetic contactor A, B, C Supply line

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H02J 9/06 504 H02J 9/06 504B 504D (72) Inventor Jun Hirose Tanabe Nitta, Kawasaki-ku, Kawasaki-shi, Kawasaki No. 1-1 F-term in Fuji Electric Co., Ltd. (reference) 5G015 GA05 HA04 HA14 JA02 JA09 JA32 JA34 JA53 JA55 5G066 AA04 BA03 CA09 DA07 DA08 HB09 JA02 JA13 JB03 KA01 5H007 BB05 CA01 CC32 5H420 BB12 CC02 CC04 CC06 DD03 EA29 EB39 EB47

Claims (8)

[Claims] 1. A circuit breaker provided on a first supply line of a commercial power supply, an auxiliary transformer connected in series to an output side of the circuit breaker, and an auxiliary transformer provided on an output side of the auxiliary transformer, A second supply line for supplying the electric power to the load side, a second inverter for varying an applied voltage to the auxiliary transformer, and a control device for controlling on / off operation of the second inverter. When power saving to the load side is performed, the on / off operation of the second inverter is controlled by the control device, a first voltage is applied to the auxiliary transformer, and the power to the load side is controlled. In the case of compensating for the voltage, the control device controls the on / off operation of the second inverter, and applies a second voltage having the phase of the first voltage inverted to the auxiliary transformer. Power supply system characterized by being performed. 2. A first inverter and a battery are connected in series to an output side of the auxiliary transformer, and the control device controls driving of the first and second inverters in three modes. The power supply system according to claim 1, wherein power is supplied to a load side. 3. A first mode of the three modes is to drive and control only the second inverter to supply power from the commercial power supply to a load side. In the mode, the power from the commercial power supply and the power from the battery are supplied to the load side by controlling the driving of the first inverter and the second inverter. 3. The method according to claim 2, further comprising: driving the first inverter and the second inverter to supply the load side with electric power obtained by subtracting electric power for charging the battery from electric power of the commercial power supply. A power supply system according to claim 1. 4. When the supply of electric power from a commercial power supply to the load side is interrupted due to a power failure or the like, the control device controls the driving of the first inverter, and reduces the DC power from the battery to the first inverter. The power supply system according to claim 2, wherein the power is converted into AC by one inverter and supplied to the load side. 5. A first step of connecting an auxiliary transformer in series to an output side of a circuit breaker provided with a first supply line of a commercial power supply, and a second supply line provided on an output side of the auxiliary transformer. A second step of supplying the electric power from the commercial power supply to the load side via a power supply, a third step of varying the voltage applied to the auxiliary transformer by a second inverter, and a power saving to the load side. Performing a fourth step of controlling the on / off operation of the second inverter and applying a first voltage to the auxiliary transformer; and compensating a voltage of power to the load side. Controlling the on / off operation of the second inverter and applying a second voltage with the phase of the first voltage inverted to the auxiliary transformer. . 6. The fourth and fifth steps include: controlling a first inverter and a second inverter connected in series with a battery to an output side of the auxiliary transformer in three modes; The power supply method according to claim 5, further comprising a sixth step of controlling power supply to a load side. 7. The method according to claim 6, further comprising: controlling in a first mode in which power from the commercial power supply is supplied to a load by driving and controlling only the second inverter. Controlling the first inverter and the second inverter in a second mode for supplying power from the commercial power supply and power from the battery to a load side by driving and controlling the first inverter and the second inverter; Driving the second inverter to control the load side in a third mode in which the power for charging the battery is subtracted from the power of the commercial power supply in a third mode. The power supply method according to claim 6. 8. The method according to claim 6, wherein when the power supply from the commercial power supply to the load side is cut off due to a power failure or the like, the drive of the first inverter is controlled and the DC power from the battery is controlled. 7. The method according to claim 6, further comprising: converting AC to AC by the first inverter and supplying the AC to the load side.