JPH06315268A - Power supply device - Google Patents

Abstract

PURPOSE:To increase the overload capacity of a power supply device by connecting the output terminal of a separately excited inverter to the output terminal of a self-exciting inverter and supplying electric power to a load from both the self-exciting inverter and the separately excited inverter. CONSTITUTION:A separately excited inverter 7 is constituted of bridge-connected thyristors 9-14 and connected in parallel with the output terminal of a rectifier circuit 4 through a reactor X1. The output terminal of a self-exciting inverter 5 is connected to the AC output terminals of the thyristors 9-14 and, at the same time, to a load 8. A relation, Edi=1.35Eac.Cosr, holds among the output DC voltage Edc of the circuit 4 and the input DC current Edi, output AC voltage Eac, and angle of advance (r) of the inverter 7. The inverting amount of the inverter 7 is controlled by increasing or decreasing the current Id supplied to the inverter 7 by controlling the input DC voltage Edi and output AC voltage Eac of the inverter 7 to Eac>=Ede. The inverting amount of the inverter 7 can be adjusted by inverting the DC voltage Edi into the AC voltage Eac which is the frequency of the inverter 5 and adjusting the angle (r).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a load facility power supply device used for an uninterruptible power supply device, a constant voltage constant frequency power supply device, a frequency conversion device and the like.

[0002]

2. Description of the Related Art Conventionally, as an uninterruptible power supply device using an inverter, one shown in FIGS. 3 and 4 has been known. As shown in FIG. 3, the thyristor 3 is connected in parallel to the uninterruptible power supply 2 connected to the AC input power supply 1. As shown in FIG. 4, the uninterruptible power supply 2 has a forward conversion circuit 4 connected to the AC input power supply 1.
And a self-excited inverter 5 to which the output DC voltage of the forward conversion circuit 4 is applied, and a storage battery 6 charged with the DC voltage of the forward conversion circuit 4.

In the uninterruptible power supply 2 shown in FIG.
When an overload exceeding the withstanding capacity of the self-excited inverter 5 is applied, the thyristor 3 is turned on to supply electric power to the load through the thyristor 3 (bypass), and the self-excited inverter 5
Is being protected. However, during a power failure, electric power cannot be supplied via the thyristor 3, so that the self-excited inverter 5 cannot cope with an overload at that time. Therefore, it is necessary to take measures such as increasing the capacity of the uninterruptible power supply 2 in anticipation of overload.

As an example, as an AC output rating of the uninterruptible power supply 2, 100% continuous -125% 10 minutes -15
There is 0% for 10 seconds. The overload resistance of the uninterruptible power supply 2 is about 150%.

Recently, there are many rectifier loads such as CPUs, and
The inrush current of an electrolytic capacitor or the like is large, and a steep load of several ms is often used. Therefore, in the event of a power failure, as a measure against overload, the load side is restricted so that no load exceeding the overload withstand capacity of the inverter is applied.

[0006]

In general, semiconductor applied equipment generally cannot have a large overload resistance, and there are many kinds of loads that are overloaded. Therefore, for example, in an uninterruptible power supply, even with a short load of several ms, 125% for 10 minutes as shown in FIG.
The output rating may be -100% continuous for 150% for 10 seconds. Then, power is supplied via a bypass to a load that is equal to or higher than the overload withstanding capacity of the inverter.

However, in the inverter of the conventional uninterruptible power supply, it is impossible to supply electric power through the bypass at the time of a power failure in which the input from the AC input power supply is cut off, so that there is a problem that the overload withstand capability is lowered. is there.

An object of the present invention is to provide a load equipment power supply device capable of achieving a large overload tolerance.

[0009]

In order to achieve the above object, the present invention comprises a self-excited inverter and a separately excited inverter connected to an output terminal of the self-excited inverter. Power is supplied from the inverter to the load, and power is also supplied from the separately excited inverter to the preload.

The present invention further comprises a self-excited inverter and a separately excited inverter connected to the output terminal of the self-excited inverter, wherein the self-excited inverter is provided at times other than a power failure when the AC input power is cut off. Power is supplied to the load only from the power source, and power is supplied to the load from both the self-excited inverter and the separately excited inverter during a power failure.

[0011]

In the present invention, since electric power is supplied to the load from both the self-excited inverter and the separately excited inverter,
A large overload tolerance can be taken.

[0012]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention. FIG. 2 is a block diagram showing the separately excited inverter in the embodiment of FIG. The inverter according to the embodiment of FIGS. 1 and 2 has the same components as the reference numbers of FIG.

As shown in FIG. 1, the output terminal of the self-excited inverter 5 is connected to the output terminal of the separately excited inverter 7. Electric power is supplied from the self-excited inverter 5 to the load 8 and electric power is also supplied from the separately excited inverter 7 to the load 8.

The separately excited inverter 7 is composed of thyristors 9 to 14 connected in a bridge as shown in FIG. 2, and is connected in parallel to the output terminal of the forward conversion circuit 4 via a reactor X1. The self-excited inverter 5
The output terminal of is connected to the AC output terminals of the thyristors 9 to 14 and the input terminal of the load 8.

Here, the output DC voltage of the forward conversion circuit 4 is Edc, the input DC voltage applied to the separately excited inverter 7 is Edi, the output AC voltage of the separately excited inverter 7 is Eac, and If the control lead angle of the separately excited inverter 7 is γ, Edi = 1.35Eac
The relationship of cosγ holds. When the current supplied to the separately excited inverter 7 is Id, the inverse conversion amount of the separately excited inverter 7 is controlled by increasing / decreasing Id by controlling Edc ≧ Edi. The input DC voltage Edi applied to the separately excited inverter 7 is equal to the input DC voltage Edi.
It is possible to adjust the inverse conversion amount by controlling the value of γ.

A control circuit for controlling the operation of the separately-excited inverter 7 is provided so that the separately-excited inverter 7 is turned off only when the AC input power supply 1 is cut off, and only from the self-excited inverter 5. Electric power is supplied to the load 8 and the self-excited inverter 5 and the separate-excited inverter 7 are set to 0N for the separately-excited inverter 7 at the time of power failure.
Power may be supplied to the load from both of the above.

The configuration as in the above embodiment can cope with an overload exceeding the capacity of the self-excited inverter. In addition, it is possible to handle overload even during a power failure when the AC input power of the uninterruptible power supply is cut off. Furthermore, when the bypass power supply voltage and frequency fluctuate significantly in the bypass synchronous operation method, the output voltage and frequency of the uninterruptible power supply device are also tracked and controlled, and thus fluctuate significantly, and in some cases it may not be practical. In such a case, if an operating method is used in which a separately excited inverter is connected, it is possible to cope with overload withstanding. The bypass operation in this case is asynchronous operation.

[0019]

As described above, according to the present invention, the electric power can be supplied to the load from both the self-excited inverter and the separately excited inverter, so that the overload withstand capability can be increased.

[Brief description of drawings]

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

FIG. 2 is a circuit diagram showing a separately excited inverter in the embodiment of FIG.

FIG. 3 is a block diagram showing a conventional uninterruptible power supply.

FIG. 4 is a block diagram showing a conventional inverter.

FIG. 5 is a waveform diagram for explaining the overload withstanding capability of a conventional inverter.

[Explanation of symbols]

 1 ... AC input power supply 2 ... Uninterruptible power supply device 4 ... Forward conversion circuit 5 ... Self-excited inverter 6 ... Storage battery 7 ... Separately excited inverter 8 ... Load 9-14 ... Thyristor

Claims (2)

[Claims] 1. A self-excited inverter and a separately-excited inverter connected to an output terminal of the self-excited inverter, wherein electric power is supplied from the self-excited inverter to a load and the load is also supplied from the other-excited inverter. An electric power supply device for load equipment, which supplies electric power to a load facility. 2. A self-excited inverter and a separately-excited inverter connected to the output end of the self-excited inverter, wherein only the self-excited inverter loads to a load except during a power failure when the AC input power is cut off. A load facility power supply device that supplies power and supplies power to the load from both the self-excited inverter and the separately excited inverter during a power failure.