JPH0538055A - Power supply - Google Patents

Abstract

PURPOSE:To enhance reliability in the operation of power supply by providing a current control loop in the minor loop of each output voltage control loop of a plurality of power supplies thereby limiting the output current from the power supply at a predetermined level for a predetermined time after a time point when the output current exceeds a set level. CONSTITUTION:A current controller 140 detects overcurrent of an inverter 130 and feeds an output current detection signal from a current detector 142 back to the input side of the current controller 140 for a predetermined interval when the overcurrent flows. A current minor loop control having function for limiting the output current at a predetermined level is then operated for the predetermined interval when the overcurrent flows thus controlling the output current of the inverter 130. According to the invention, a sound uninterruptible power supply is not damaged by the fault current due to inner short circuit in the counterpart resulting in the enhancement of reliability in the operation of power supply.

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 supply units 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. A conventional technique related 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. Further, 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 to DC power by the converter 131 via the switch 135, smoothed by the filter capacitor 132, and converted again to AC power 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 shows the switch 134 and its control circuit. 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 output voltage reference 1
36 and the output voltage detector 137 are compared, and the output voltage control is performed by the voltage controller 138.
9, the detection signal of the output current detector 142 and the reference signal of the current reference 139 are associated with each other, and the output current control is performed by the current controller 140.
In order to operate 0 in PWM control, the PWM control circuit 14
Control via 1. As shown in FIG. 3, in the uninterruptible power supply 11 having a current minor loop, the current minor loop has a current limiting function of limiting the output current to a predetermined value. Even if an internal short-circuit accident of the uninterruptible power supply 11 occurs, the flow of the accident current from the healthy uninterruptible power supply 11 side can be limited, so that there is no risk of the two uninterruptible power supply 11 accidentally stopping. However, the uninterruptible power supply 11 has a current minor as shown in FIG.
If a load is provided, a load 12 such as a large-capacity computer that requests input of a waveform similar to a sine wave disturbs the output voltage waveform of the uninterruptible power supply 11 due to fluctuations of the load 12 during normal operation. There is a problem that causes misbehavior.

Therefore, in the actual uninterruptible power supply 11,
If the current minor loop as shown in FIG. 3 cannot be provided and one of the two uninterruptible power supply units 11 causes an accident due to an internal short-circuit or the like, the healthy uninterruptible power supply unit 11 also has an accident. There is a problem that the uninterruptible power supply unit 11 on the sound 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 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
There was a problem in the prior art 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 a 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, when the other party has an accident, the power supply device on the healthy side is overcurrent It is an object of the present invention to provide a power supply device that can prevent both from collapsing.

[0012]

In order to achieve the above object, the present invention is applied to a power supply device, which is provided with a current controller 140 as shown in FIG.
Is detected as an overcurrent, and the current detector 1 is connected to the input side of the current controller 140 only for a predetermined period when the overcurrent occurs.
The output current detection signal of 42 is fed back to control the output current of the inverter 130 by operating the current minor loop control having a function of limiting the output current to a predetermined value only for the predetermined period. It is characterized by being configured.

[0013]

With the configuration described above, for example, as shown in FIG.
In the power supply device configured as described above, one uninterruptible power supply device 11 has an internal short-circuit accident, and a fault current flows into the other uninterruptible power supply device 11 on the healthy side, but the uninterruptible power supply device on the side where the accident has occurred. For a predetermined period until the switch 134 of the device 11 is disconnected, the uninterruptible power supply device 11 on the healthy side can limit the output current to a level at which overcurrent is not detected.

As a result, the sound uninterruptible power supply 11 is
Due to the internal short circuit on the other side, there is no risk of the electric current from collapsing due to the accident current, and even in the redundant system configuration in which two uninterruptible power supply units 11 are connected in parallel as shown in FIG. it can.

[0015]

DETAILED 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 sets 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 control of the inverter 130 is performed with the same characteristics as the control loop without.

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 timing 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 the 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 uninterruptible power supply 11 has an internal short circuit accident, and the other uninterruptible power supply 1 is healthy.
Even if a fault current flows from the inverter 1 of FIG. 1, this fault current is prevented by the control provided with the current minor loop as described above from causing a healthy uninterruptible power supply unit side to stop due to an overcurrent. 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 inverter 1 in order to prevent another healthy uninterruptible power supply 11 from accidentally stopping due to overcurrent when an internal short-circuit accident in one uninterruptible power supply 11 occurs.
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 in place 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 two uninterruptible power supply devices 11 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]

As is apparent from the above description, according to the present invention, it is possible to provide a power supply device which can obtain the following effects.

(1) Since the output voltage control circuit of the power supply device does not perform the current control action as a minor loop, even if the load fluctuates in a steady state, the output voltage does not fluctuate, and the input voltage does not fluctuate. It does not malfunction loads such as large computers that malfunction due to long-term distortion.

(2) Even if one of the power supplies connected in parallel flows an accident current due to an internal short circuit or the like, the other healthy power supply detects that the output current exceeds a predetermined value, and the voltage is output only for a preset time. Since the current control is performed as the minor loop of the control circuit, it is possible to prevent the output current of the power supply device on the healthy side from increasing to the overcurrent level.

(3) Due to the above operation, even if any one of a plurality of power supply units connected in parallel causes an accident, the power supply unit on the healthy side does not collapse due to an overcurrent, and the reliability is high. A high power supply device can be provided.

[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 the 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)

Claims: 1. A plurality of power supply devices are connected in parallel,
In a power supply device that configures a redundant system and supplies power to an important load, 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 supply device comprising a current control loop for limiting the output current to a predetermined value for a predetermined time after the start.