JPH11178244A - Controller for changeover switch to uninterruptible power supply - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect anomalies in a cooling fan, regardless of the temperature around a power converter and stop operation to prevent troubles in the power converter. SOLUTION: When a first changeover switch a4 is brought in on-state by a means a6 for selecting and on/off-driving the first change-over switch a4 or a second change-over switch a5, a discriminating means a9 discriminates a cooling fan a1 as being faulty. According to the discrimination by the discriminating means a9, the controller stops a power converter a2 and at the same time turns off the first changeover switch a4 and on the second changeover switch a5 via the means a6 for selecting and on/off-driving the first change-over switch a4 or the second changeover switch a5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an uninterruptible power supply having a cooling fan.

[0002]

2. Description of the Related Art Conventionally, in an uninterruptible power supply, for example, a temperature detector which operates at a predetermined temperature is provided in a converter, and an abnormality in the temperature of the power converter is detected. There have been proposed various methods of controlling a changeover switch of an uninterruptible power supply device having means for stopping a power converter and simultaneously turning off the first changeover switch and turning on a second changeover switch.

That is, in an operation state of a power converter that requires forced air cooling by a cooling fan, the temperature of the power converter itself increases due to heat generated from the power converter. On the other hand, the power converter is generally configured by a semiconductor element. If the semiconductor element exceeds the operation compensation temperature of the element, the element itself may be damaged, and the operation of the power converter may not be continued. Therefore, the power converter needs to operate at a temperature lower than the operation guarantee temperature of the semiconductor device. For example, when the rotation of the cooling fan becomes abnormal and the number of rotations decreases, and the temperature of the power converter itself increases, the temperature detector provided in the converter converts the predetermined temperature set below the operation compensation temperature of the semiconductor element. And stops the operation to prevent the power converter from malfunctioning, and at the same time, outputs a signal to turn off the first switch and turn on the second switch.

[0004]

However, in the above-mentioned prior art, when the temperature around the power converter is high, the temperature of the power converter itself becomes high even if the cooling fan rotates normally.
In some cases, the temperature detector operates to stop the operation of the power converter, and at the same time, output a signal to turn off the first switch and turn on the second switch.

An object of the present invention has been made in view of the above circumstances, and is intended to detect an abnormality in a cooling fan without affecting the ambient temperature of the power converter and to prevent an abnormality in the power converter. It is an object of the present invention to provide a control method for stopping operation and simultaneously turning off the first changeover switch and turning on the second changeover switch.

[0006]

In order to achieve the above object, as shown in FIG. 1, in an uninterruptible power supply, a power converter a2 requiring forced air cooling by a cooling fan a1 is used.
A first changeover switch a4, a second changeover switch a5 provided between the load, a spare AC power supply a3, a power converter a2 and an AC power supply a3, respectively, Means a6 for selecting the changeover switches a4 and a5 to perform on / off driving, a rotation detecting means a7 for detecting the rotation of the cooling fan a1, and a rotation for determining the rotation fluctuation of the cooling fan a1 based on the detection result of the rotation detecting means a7. Fluctuation indexing means a8;
Abnormality determination means a9 for determining that the cooling fan a1 is abnormal when an index result of the rotation fluctuation index means a8 falls below a predetermined determination value; operation state detection means a10 for detecting an operation state of the power converter a2; The detection result of the operating state detecting means a10 indicates the operating state, and the first and second changeover switches a4,
A5 is selected by means a6 for selecting and driving on and off.
When the changeover switch a4 is in the ON state, the cooling fan a
The power converter a2 is stopped according to the result of the abnormality determination by the determination means a9 which determines that the first abnormality has occurred, and at the same time, the first and second changeover switches a4 and a5 are selected and turned on and off by the first means a6. Control means for turning off the changeover switch a4 and turning on the second changeover switch a5.

That is, according to the above configuration, as shown in FIG. 1, the operating state detecting means a10 detects the operating state of the power converter a2 when operating. Means a6 for selecting the first and second changeover switches a4 and a5 to drive them on and off
Selects the first and second changeover switches a4 and a5 and drives them on and off. The rotation detecting means a7 is provided with a cooling fan a1.
, The rotation speed of the cooling fan a1 is detected based on the detection result. Further, when the rotation fluctuation index result falls below a predetermined judgment value, the abnormality judging means a9 judges that the cooling fan a1 is abnormal.

The result of the detection by the operating state detecting means a10 is the operating state of the converter a2 and means for selecting the first and second changeover switches a4 and a5 to perform on / off driving.
6, when the first changeover switch a4 is selected and turned on, the power converter a2 is stopped by the abnormality judgment of the abnormality judgment means a9, and at the same time, the first and second changeover switches a4, a5 The first changeover switch a4 is turned off and the second changeover switch a5 is turned on by means a6 for selecting and turning on and off, and the load power supply is continued.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a switching method according to the present invention will be described below in detail with reference to FIGS.

FIG. 2 is a schematic configuration diagram showing a part of the inverter power converter 1 and the changeover switches 2 and 3 of the uninterruptible power supply provided with the changeover switch control method in this embodiment. In FIG. 1, power supplied from a DC power supply is converted into AC power by an inverter power converter 1 including semiconductor elements s1 to s4, and is supplied to a load 4 via a changeover switch 2. Inverter power converter 1
Is provided with operating state detecting means 11 for controlling the operation and stopping of the inverter power converter 1 and detecting the operating state of the inverter power converter 1.

The inverter power converter 1 is forcibly air-cooled by a cooling fan 5 to prevent the temperature of the inverter power converter 1 itself from rising due to heat generated from the semiconductor elements s1 to s4. The cooling fan 5 is provided with a rotation speed sensor 12 as rotation detection means for detecting the rotation speed of the cooling fan 5.

The rotation speed sensor 12 is configured to output a signal k1 which is increased or decreased by an increase or decrease in the rotation speed of the cooling fan 5. Then, the output signal k of the rotation speed sensor 12
1 is taken into a comparator 13 provided with a rotation fluctuation determining means and an abnormality determining means.

In the comparator 13, the rotation speed sensor 12
Is compared with a reference value k0. The reference value k0 indicates that the semiconductor device s
It is obtained from the level of the output signal of the rotation speed sensor 12 when the temperature of the semiconductor elements s1 to s4 rises and becomes equal to or higher than the operation compensation temperature of the semiconductor elements s1 to s4. And the two signals k
If the level of the output signal k1 of the rotation speed sensor 12 among the 0 and k1 levels is equal to or less than the reference value k0, it is determined that the cooling fan 5 is abnormal.

The result and the operating state detecting means 11 for detecting the operating state of the inverter power converter 1 allow the inverter power converter 1 to be in the operating state,
The operation of the inverter power converter 1 is stopped by the operation state detecting means 11 of the inverter power converter 1 when the changeover switch 2 is turned on by the on / off driving means 14 of FIG. At the same time, the changeover switch 2 is turned off by the on / off drive means 14 of the changeover switches 2 and 3, the changeover switch 3 connected to the backup AC power supply is turned on, and the AC power is supplied to the load 4 without interruption. become able to.

FIG. 3 is an operation block diagram showing an operation state of each unit in FIG. In the figure, the point X indicates a case where the rotation speed of the cooling fan 5 starts to decrease.

Although the above description has been made in the case of a single-phase inverter as a power converter, a three-phase inverter converter and
In the case of a converter, the same control as described above is performed.

[0017]

As described above in detail, according to the present invention, the rotation fluctuation of the cooling fan is determined based on the detection of the rotation of the cooling fan without affecting the air temperature around the power converter, and the result of the calculation is determined to be a predetermined value. In the uninterruptible power supply device equipped with means for determining that the cooling fan is abnormal when the value falls below the judgment value, if the cooling fan fails while the power converter is operating, the abnormality of the power converter is prevented. The load can be connected to the backup AC power supply without interruption by controlling the changeover switch at the same time and stopping the operation.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a control device of a changeover switch of an uninterruptible power supply according to an embodiment of the present invention.

FIG. 2 is a circuit diagram showing a control method of a changeover switch that embodies FIG. 1;

FIG. 3 is a waveform chart showing an operation in FIGS. 1 and 2;

[Explanation of symbols]

1. Inverter power converter 2, 3, changeover switch
Reference numeral 4 denotes a load, 5 denotes a cooling fan, 11 denotes an operation state detecting means of the inverter power converter, 12 denotes a rotation speed sensor, 13 denotes a comparator, and 14 denotes on / off driving means of a changeover switch.
s4: semiconductor element, k1: output signal of rotation speed sensor,
k0: Reference value of the comparator.

Claims (1)

[Claims] 1. A power converter which requires forced air cooling by a cooling fan, a spare AC power supply, and first and second power converters provided between each of the power converter and the AC power supply and a load. 2
Changeover switch, means for selecting the first and second changeover switches for on / off driving, rotation detecting means for detecting rotation of the cooling fan, and the cooling fan based on the detection result of the rotation detecting means. An uninterruptible power supply device comprising: a rotation fluctuation indexing unit that calculates the rotation fluctuation of the motor; and an abnormality determination unit that determines that the cooling fan is abnormal when the indexing result of the rotation fluctuation indexing unit is less than a predetermined determination value. Operating state detecting means for detecting an operating state of the power converter, and means for selecting the first and second changeover switches to perform on / off driving when the detection result of the operating state detecting means is an operating state, When the first changeover switch is in the ON state, the power converter is stopped and, at the same time, the first switchover is performed, based on the abnormality determination result of the abnormality determination means for determining that the cooling fan is abnormal. Controller of the change-over switch of the uninterruptible power supply having means for turning on the second changeover switch off the switch.