JP2001178024A - Emergency power supply unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate instantaneous power failure while encountering long power failure, stabilize voltage and phases, and attain reduction in the size and weight of an apparatus by reducing the capacity of a backup battery and simplifying the circuit structure. SOLUTION: This emergency power supply unit is provided with a power switching part 3 for selectively switching a commercial power source 1 as an input power source and a motor generator 2, a rectifier 4 for converting AC into DC and outputting it to a DC circuit 5, and an inverter 6 for inverting the DC of the DC circuit 5 to AD and outputting it to a load. The DC circuit 5 has a battery 10, connected through a parallel circuit of a step-up DC-DC converter 8 and a step-down DC-DC converter 9. When the voltage of the DC circuit 5 is dropped at the time of power failure, the voltage of the battery 10 is boosted by the step-up DC-DC converter 9, and a controller 12 having a power failure detector 11 switches the startup of the motor generator at the time of power failure, and the power switching part 3 after stabilization to continue to supply power to a load 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic switching control device capable of automatically switching to an emergency power generator when a commercial power supply is interrupted. The present invention relates to an uninterruptible emergency power supply capable of continuing supply.

[0002]

2. Description of the Related Art A portable power generator of a type driven by an engine is integrally incorporated into a portable power generator, which is compact and capable of automatically switching a power source. As an emergency power supply unit that switches the power supply source from the generator to the commercial power side by detecting the power supply source of the 10-20475
0 has already been proposed by the applicant. However, in this technology, the switching between the commercial power supply and the power generator is performed by an electromagnetic relay or the like.
It is not suitable for loads in electronic devices such as computers that require strict requirements for momentary power failures and voltage and phase constants.

In addition, malfunction of an electronic device such as a computer during a very short power outage (for example, a few milliseconds to a few seconds from a lightning strike on a transmission line to a high-speed reclose of a circuit breaker) is avoided. Uninterruptible power supplies installed for this purpose are also known, but cannot cope with long-term power outages.

On the other hand, there are large-scale emergency power supplies such as telephone exchanges, but they have large-capacity batteries, and have the drawback that the whole equipment becomes large-sized and heavy and expensive. .

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the foregoing circumstances, and has been made in response to a long-term power failure, has no instantaneous power failure, has a stable voltage and phase, and has a backup battery. It is an object of the present invention to provide an emergency power supply device capable of reducing the size and weight of the device by reducing the capacity of the device and simplifying the circuit configuration.

[0006]

In order to achieve the above object, according to the first aspect of the present invention, a power generator, a power switching unit for selecting a commercial power supply and the power generator as an input power source, and a power switching unit A first power conversion means for converting an alternating current input through the DC to a direct current and outputting it to a DC circuit, a second power converting means for converting the direct current input from the DC circuit to an alternating current and outputting to a load, The control unit includes a battery connected via DC / DC power conversion means, and a control unit having a power failure detection means for detecting a power failure of a commercial power supply. After a predetermined value of the generator output is detected, a switching command of the power switching unit is issued,
The output of the power generator is supplied to the first power conversion means, and the DC / DC power conversion means converts the battery voltage and outputs it to the DC circuit when the voltage of the DC circuit drops.

According to a second aspect of the present invention, a DC / DC power converter according to the first aspect includes a parallel circuit of a step-up DC / DC converter and a step-down DC / DC converter.
The DC converter boosts and outputs the battery voltage so that the voltage of the DC circuit is maintained at the control output voltage set value V1, and the step-down DC / DC converter operates when the DC circuit voltage is equal to or higher than the set value V2 to connect to the battery. Charge, and V1 <V2 <V3 between the voltage value V3 of the first power conversion means.
It is characterized by having the following relationship.

According to the first aspect of the present invention, when the commercial power supply is interrupted, the battery voltage is boosted by the DC / DC power conversion means to maintain the DC circuit voltage, the starting generator is started, and the output voltage is set to the predetermined value. Since the power switching unit is switched when the power is turned off, the output of the prime mover is replaced by the commercial power supply before the power failure and is applied to the DC circuit via the first power conversion means, and power is supplied to the load by the second power conversion means. Is continued.

According to the second aspect of the present invention, the DC / DC power converter comprises a step-up DC / DC converter and a step-down DC / DC converter.
Constructs a parallel circuit of DC converter
The / DC converter boosts the battery voltage to the V1 voltage value and supplies it to the DC circuit when the output voltage of the first power conversion means drops due to a commercial power failure. In addition, step-down DC
The / DC converter charges the battery when the DC circuit voltage value is equal to or higher than V2, and stops operation when the DC circuit voltage value is lower than V2. Step-up DC / DC converter and step-down DC
Each set voltage value is determined so that the / DC converter performs an exclusive operation.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described based on embodiments of the present invention shown in the accompanying drawings.

FIG. 1 is a circuit block diagram showing an embodiment of the present invention.

In FIG. 1, a commercial power supply 1 or a power generator 2 is selected as an input source by a power switching unit 3 and is connected to a rectifier 4 as first power conversion means. The rectifier 4 rectifies the AC of the commercial power supply 1, converts the AC into a DC voltage having a voltage value V 3, and outputs the DC voltage to the DC circuit 5. The inverter 6 as the second power conversion means converts the DC from the DC circuit 5 into AC, and supplies the output AC to the load 7.

The DC circuit 5 includes a step-down DC / DC converter 8 as a DC / DC power conversion means and a step-up DC / DC converter.
A DC converter 9 has a parallel connection circuit, and is connected to the battery 10 via this circuit. In other words, a battery 10 having a voltage different from the voltage of the DC circuit 5 is provided as a backup for a power failure, and the voltage is selected to be lower than the voltage of the DC circuit 5 to reduce the number of cells in series and increase the battery capacity. Restrained. Since the voltage of the DC circuit 5 and the voltage of the battery 10 are not the same, when charging the battery 10, the step-down DC / DC converter 8
Operates, and when the battery 10 is discharged, the boost DC /
The DC converter 9 operates to boost the battery voltage and supply it to the DC circuit 5.

The step-down DC / DC converter 8 includes a rectifier 4
The rectifier 4 is activated when the rectifier 4 is equal to or higher than a set value V2 which is lower than the voltage value V3 of the DC circuit 5 when the commercial power supply 1 is used as an input source. Is reduced to a voltage at which the battery 10 is charged, and the battery 10 is charged. When the voltage of the DC circuit 5 becomes smaller than the set value V2, the operation of the step-down DC / DC converter 8, that is, the charging of the battery 10 is stopped. It should be noted that the set value V2 is a small hysteresis V2 in order to stabilize the step-down DC / DC converter 8.
a, V2b (condition: V2a <V2b) is desirably set so that operation is released when V2a or less and operation is performed when V2b or more.

The step-up DC / DC converter 9 has a control output voltage set value V1 (condition V1 <V3).
It monitors the voltage of the DC circuit 5 and operates when the voltage is about to drop below V1, thereby increasing the voltage of the battery 10 and maintaining the voltage of the DC circuit 5 at the V1 value. When the step-up DC / DC converter 9 operates and the battery 10 is used as an energy source, the step-down DC / DC
In order to stop the charging operation of the / DC converter 8, the relationship V1 <V2 <V3 is established between the control output voltage set value V1, the set value V2, and the voltage value V3 of the first power conversion means. Set.

Thus, normally, the commercial power supply 1 (AC) → the power switching unit 3 → the rectifier 4 (DC) → DC circuit 5 (DC) →
AC power is supplied to the load 7 through a path from the inverter 6 (AC) to the load 7. Further, since the voltage value V3 of the DC circuit 5 is equal to or higher than the set value V2, the step-down type D
It is charged via the C / DC converter 8.

Here, when the commercial power supply 1 fails, the power failure detector 11 detects the power failure and sends a power failure signal to the control unit 12. The control unit 12 gives a start signal to the power generator 2 to start the power generator 2. On the other hand, since the rectifier 4 loses its input power, the output to the DC circuit 5 is stopped, but the voltage of the DC circuit 5 does not drop instantaneously due to the accumulated charge of the capacitor 13 inserted in the DC circuit 5. It is going down.

When the voltage of the DC circuit 5 drops below the set value V2, the step-down DC / DC converter 8 stops, and when the voltage drops further, the step-up DC / DC converter 9 operates.
The voltage of the battery 10 is boosted to maintain the DC circuit 5 at the control output voltage set value V1 to prevent a further decrease, and to supply power to the inverter 6. That is, the electric power stored in the battery 10 is released to the DC circuit 5 via the step-up DC / DC converter 9, and the inverter 6 converts this DC into AC in conjunction with the instantaneous discharging action of the capacitor 13 inserted in the DC circuit 5. And the load 7 is supplied to the load 7, so that the load 7 can continue operation without a power failure or a change in voltage and phase.

When the start of the generator 2 is completed and the output voltage is stabilized, the control unit 12 detects a predetermined value (voltage or the like) and switches the power switching unit 3 to the side of the generator 2, and outputs the output to the rectifier 4. To supply.

Therefore, since the power generator 2 replaces the commercial power supply 1, the power generator 2 (AC) → the power switching unit 3 → the rectifier 4 (DC) → DC circuit 5 (DC) → inverter 6 (AC) → Since power is supplied through the path of the load 7, the load 7 can continue to operate without power failure. At that time, the DC circuit 5
Is equal to or higher than the set value V2 (of course, equal to or higher than V1),
The step-up DC / DC converter 9 stops, and the step-down DC / DC
The DC converter 8 operates to charge the battery 10.

When the power failure of the commercial power supply 1 is restored, the power failure detector 11 detects the recovery from the power failure and sends it to the control unit 12. The control unit 12 switches the power switching unit 3 to the commercial power source 1 and stops the power generator 2. Note that even if power is not supplied to the rectifier 4 in a short time during the switching operation of the power switching unit 3, the power supply to the load 7 is not affected as in the case of the above-described power failure.

Although the embodiments of the present invention have been described in detail, the present invention is not limited to the above embodiments, and various design changes can be made without departing from the present invention described in the appended claims. It is possible to do. For example, a step-down DC / DC converter 8 as a DC / DC power conversion means and a step-up DC
The / DC converter 9 may be exclusively activated / deactivated.

[0023]

According to the first aspect of the present invention, the power generator, the power switching unit for selecting the commercial power supply and the power generator as the input power source, and converting the alternating current input through the power switching unit into direct current. First power conversion means for converting and outputting to a DC circuit; second power conversion means for converting DC input from the DC circuit to AC and outputting the AC power to a load; and DC / DC power conversion means for the DC circuit. A connected battery and a control unit having a power failure detection unit that detects a power failure of the commercial power supply,
In response to the power failure detection of the power failure detection means, the control unit issues a switching command of the power switching unit after starting the power generator and detecting a predetermined value of the power output of the power generator, and the output of the power generator is supplied to the first power conversion means. When the DC circuit voltage drops, the DC /
Since the DC power conversion means converts the battery voltage and outputs the battery voltage to the DC circuit, it is possible to provide an emergency power supply device that can cope with a long-term power failure, has no instantaneous power failure, and has stable voltage and phase.

Further, in the invention according to claim 2, the DC / DC power converter includes a parallel circuit of a step-up DC / DC converter and a step-down DC / DC converter.
The / DC converter boosts and outputs the battery voltage so that the voltage of the DC circuit is maintained at the control output voltage set value V1, and the step-down DC / DC converter operates when the DC circuit voltage is equal to or higher than the set value V2. Therefore, the size and weight of the device can be reduced by reducing the capacity of the backup battery and simplifying the circuit configuration.

[Brief description of the drawings]

FIG. 1 is a block diagram of a circuit configuration according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Commercial power supply 2 ... Power generator 3 ... Power switching part 4 ... Rectifier (1st power conversion means) 5 ... DC circuit 6 ... Inverter (2nd power conversion means) 7: Load 8: Boost DC / DC converter (DC / DC power conversion means) 9: Step-down DC / DC converter (DC / DC power conversion means) 10: Battery 11: Detection of power failure Means 12 Control unit

Claims (2)

[Claims] 1. A power generator, a power switching unit for selecting a commercial power supply and the power generator as an input power source, and converting an alternating current input through the power switching unit into direct current and outputting the direct current to a direct current circuit. A first power converter, a second power converter that converts DC input from the DC circuit into AC and outputs the AC to a load, and a battery connected to the DC circuit via DC / DC power converter. A control unit having a power failure detection means for detecting a power failure of the commercial power supply, wherein the power failure is detected by the power failure detection means so that the control unit starts the power generator and detects a predetermined value of the power output of the power generator. In response to a switching command of a switching unit, the output of the power generator is supplied to the first power conversion means, and the DC / DC power conversion means converts the battery voltage when the voltage of the DC circuit drops. And outputting to the DC circuit. 2. The DC / DC power converter includes a parallel circuit of a step-up DC / DC converter and a step-down DC / DC converter, and the step-up DC / DC converter controls a voltage of the DC circuit by a control output voltage. The battery voltage is boosted and output so as to maintain the set value V1, and the step-down DC / DC converter operates when the DC circuit voltage is equal to or higher than the set value V2 to charge the battery.
V1 <V2 between the voltage value V3 of the first power conversion means.
2. The emergency power supply according to claim 1, wherein the emergency power supply has a relation of V3.