JP2500877B2 - Power supply - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply unit that requires reliability, and a plurality of power supply units are configured in a redundant system. The present invention relates to a power supply device that can be disconnected and can continue load power supply with the remaining healthy power supply device.

[0002]

2. Description of the Related Art An example of a power supply device to which the present invention is applied is an uninterruptible power supply device. The prior art will be described below with reference to an uninterruptible power supply.

As a prior art for constructing a redundant system by connecting a plurality of uninterruptible power supplies in parallel, for example, Toshiba Review, 1991, VOL. 46, NO. 6, P456 ~
As described in P459 and the like, high reliability is required, and it is required to configure the system so that power supply to an important load is not stopped instantaneously. Prior art relating to the present invention will be described below with reference to FIGS. 2 and 3.

In FIG. 2, 10 is an input AC power supply such as a commercial power supply, 11 is an uninterruptible power supply, and 12 is a load. In addition, as components of the uninterruptible power supply 11, 130 is an inverter, 131 is a converter, 132 is a filter capacitor, 133 is an output transformer, and 134 and 135 are switches. In the uninterruptible power supply 11, the power of the input AC power supply 10 is converted into DC power by the converter 131 via the switch 135, smoothed by the filter capacitor 132, and converted into AC power again by the inverter 130. , Power is supplied to the load 12 via the output transformer 133 and the switch 134.

In FIG. 2, two uninterruptible power supplies 11 are connected in parallel, and a redundant system configuration is provided so that even if one of them fails, another healthy uninterruptible power supply 11 can supply power to the load 12. In such a configuration, each uninterruptible power supply 11 has a rated capacity corresponding to the capacity of the load 12, and the capacity is designed so that power can be supplied by one uninterruptible power supply 11.

In order to clarify the problems of the prior art in the configuration of FIG. 2, description will be given with reference to FIG. FIG. 3 shows the inverter 130 and the output transformer 13 of the uninterruptible power supply 11.
3, the switch 134 and its control circuit are illustrated. In this figure, 136 is an output voltage reference, 137 is an output voltage detector, 138 is a voltage controller, 139 is a current reference,
140 is a current controller, 141 is a PWM control circuit, 142
Is a current detector.

In the configuration shown in FIG. 3, the voltage controller 13
8 is a signal of the output voltage reference 136 and the output voltage detector 137.
Current reference 139 for comparing the output voltage control
The current controller 140 detects the output current detector 142.
Output current control is performed by matching the signal with the current reference 139.
For outputting the signal for
The inverter 130 is PWM-controlled. Such current my
In the uninterruptible power supply 11 equipped with a null loop,
Has a function to limit the output current to a specified value with a loop.
As a result, some uninterruptible power supply 11 may have an internal short circuit.
Even if a failure occurs due to the reason, the flow of the accident current from the sound uninterruptible power supply 11 side can be limited, so that there is no risk that both uninterruptible power supply 11 will stop due to an accident. However, if the uninterruptible power supply 11 is provided with a constantly operating current minor loop, the output voltage waveform of the uninterruptible power supply 11 is disturbed due to load fluctuations during normal operation, and a waveform input of a sine wave approximation is required. problem of erroneous <br/> operate the load 12, such as a large-capacity computer is present for.

Therefore, in the actual uninterruptible power supply 11,
If a current minor loop as shown in FIG. 3 cannot be provided and one of the two uninterruptible power supply units 11 has an accident due to an internal short circuit, etc., the healthy uninterruptible power supply unit 11 also has an accident. There is a problem that the uninterruptible power supply 11 on the healthy side detects an overcurrent by the current flowing into the point and the current of the load 12 and causes an accident stop due to the overcurrent.

[0009]

As described in the related art with reference to FIGS. 2 and 3, an important power supply device such as the uninterruptible power supply device 11 has a plurality of power supply devices connected in parallel. Power is supplied to important loads with a redundant system configuration so that systems with a high social mission such as large computers will not be stopped.

However, as explained in the figure, in the redundant system configuration in which two uninterruptible power supply units 11 corresponding to the capacity of the load 12 are connected in parallel, one uninterruptible power supply unit 1
The conventional technique has a problem that the output of the other healthy uninterruptible power supply 11 stops due to an overcurrent when one internal short circuit occurs.

Therefore, even if the redundant system configuration in which two uninterruptible power supply units 11 are connected in parallel is adopted, the reliability of the power supply unit cannot be substantially improved as expected. Therefore, an object of the present invention is made in view of the above-mentioned point, and in a redundant system configuration in which power supply devices are connected in parallel, a healthy power supply device causes an overcurrent when an accident occurs on the other side. It is an object of the present invention to provide a power supply device that can prevent both from collapsing.

[0012]

To achieve the above object, a power supply device to which the present invention is applied is a plurality of power converters.
Run in parallel and some power converter fails
Keep the power converter running healthy and continue to power the load
Power supply device that supplies power to
Minor loop of each output voltage control loop of the instrument
In addition, the output current of the power converter exceeds the preset value.
When a fault occurs, the specified time until the failed power converter is disconnected
Current control to limit its output current to a specified value
It is configured by providing steps.

[0013]

[Function] By configuring as described above, a part of electric power is consumed.
The converter fails and overcurrent flows to a healthy power converter.
When the output current exceeds the preset value,
Current control means until disconnecting the faulty power converter
It acts to limit the output current to a specified value for a specified time.
U.

As a result, the sound uninterruptible power supply 11 is
Due to the internal short circuit of the other party, there is no risk of the electric current collapsing due to the accident current, and it is possible to greatly improve the operational reliability of the power supply device even in the redundant system configuration in which two uninterruptible power supply devices 11 are connected in parallel as shown in FIG. it can.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. FIG. 1 shows an embodiment of the present invention corresponding to FIG. 3 for explaining the conventional technique. In FIG. 1, the circuit components designated by the same numbers as those in FIG. 3 are circuit components having the same function, and the description thereof will be omitted. In FIG. 1, 143 is a switch, 144 is a current level detector, 145 is a switching circuit having a timed element, and 146 is a terminal for inputting a failure signal of another uninterruptible power supply.

As described above, two inverters 130 of the uninterruptible power supply 11 configured as shown in FIG. 1 are operated in parallel with the configuration shown in FIG. When the output current of the uninterruptible power supply 11 is below a predetermined level (for example, rated current), the current level detector 144 switches the switch 143 to S through the switching circuit 145.
The output signal of the current detector 142 is not controlled by comparison with the output signal of the current reference 139, and the current controller 140 controls the output signal of the current reference 139 by comparison. The output voltage of the inverter 130 is controlled with the same characteristics as the control loop not provided with.

On the other hand, when the output current of the inverter 130 exceeds a predetermined value, the detection signal of the current detector 142 is input to the current detection level detector 144, and the current level detector 144 causes the output current to exceed the predetermined value. Then, the switch 143 is switched to the S2 terminal side via the switching circuit 145. When the switch 143 is switched to the S2 terminal side,
The detection signal of the current detector 142 is compared and controlled with the output signal of the current reference 139 by the current controller 140, and the inverter 13
The current controller 140 sets P to decrease the output current of zero.
The inverter 130 is controlled via the WM controller 141.

Since the switching circuit 145 is a switching circuit having a timed element as described above, it is a preset time (for example, a number corresponding to the opening time of the switch 134) after the current level detector 144 detects a predetermined level. The switch 143 is set to the S2 terminal side only for 10 milliseconds), and then the switch 143 is automatically switched to the S1 terminal side. When the current level detector 144 and the switching circuit 145 thus operate, the current minor loop is operated within the voltage control loop of the inverter 130 only within a predetermined time of the overcurrent period of the inverter 130. Can be made.

As described above, one of the uninterruptible power supply units 11 has an internal short circuit accident, and the other uninterruptible power supply unit 1 is sound.
Even if a fault current flows from the inverter 1 of No. 1, the fault current is prevented from being stopped due to an overcurrent on the side of a healthy uninterruptible power supply by the control provided with the current minor loop as described above. it can.

When an accident occurs in one of the uninterruptible power supply units 11, the current level detector 14 is connected via the terminal 146.
4 is operated, and the switch 143 is similarly switched to the S2 terminal side through the switch 145 only for a predetermined period to operate the current minor loop.

As described above, the uninterruptible power supply 1 of FIG.
Even with the two parallel connection configuration of No. 1, when the internal short-circuit accident of one uninterruptible power supply 11 occurs, the other healthy uninterruptible power supply 11 is prevented from accidentally stopping due to overcurrent.
The output current of 30 can be suppressed. As a result, it is possible to prevent the sound uninterruptible power supply 11 from stopping due to the common fall.

As an embodiment of the present invention, in FIG. 1, the output signal of the current reference 139 is input instead of the detection signal of the current detector 142 by the switch 143 during the period when the current controller 140 is not current limited. However, this method is not limited to the present invention, and the inverter 13 can be formed by various methods.
It is obvious that the current controller 140 can be configured to operate only when 0 exceeds a predetermined current value, and the present invention is not limited to a specific control circuit configuration. Others As an embodiment of the present invention, the description is given centering on the configuration of FIG. 2 in which two uninterruptible power supply devices 11 are connected in parallel, but the present invention does not particularly limit the number of uninterruptible power supply devices 11 connected in parallel. Two or more units may be connected in parallel. Others The present invention can be implemented with various design changes within the scope of the invention.

[0023]

EFFECTS OF THE INVENTION According to the present invention, it is possible to obtain a little
The output voltage cannot be changed even when the load
A stable and stable voltage can be output.
The internal power converter may malfunction due to an internal short circuit or other failure.
A healthy power converter is a failed power converter
Output current only for a preset time until the
Since current control is performed to limit it to a specified value, it will collapse due to overcurrent.
It is possible to provide a highly reliable power supply device that does not operate.

[0024]

[0025]

[0026]

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a power supply device of the present invention by a single wire connection.

FIG. 2 is a block diagram showing a redundant system configuration of a power supply device, which is shown by a single wire connection.

FIG. 3 is a single connection block diagram of a power supply device for explaining the problems of the conventional technology.

[Explanation of symbols]

10 ... Input AC power supply 11 ...
… Uninterruptible power supply 12 …… Load 130…
… Inverter 131… Converter 132…
... Filter capacitor 133 ... Output transformer 134 ...
... switch 135 ... switch 136 ...
... Output voltage reference 137 ... Output voltage detector 138 ...
... Voltage controller 139 ... Current reference 140 ...
... Current controller 141 ... PWM control circuit 142 ...
... Current detector 143 ... Switch 144 ...
Current level detector 145 Switching circuit 146
… Terminal

Claims (1)

(57) [Claims] 1. A power supply for operating a plurality of power converters in parallel so that even if a part of the power converters fails, the power converters continue to operate soundly, and power is continuously supplied to a load. In the device, when the output current of the power supply device exceeds a preset value in the minor loop of the output voltage control loop of each of the plurality of power supply devices, a power converter that has failed
Output current to a specified value for a specified time until the
A power supply device comprising a current control means for limiting .