JP3543432B2 - Uninterruptible power system - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an uninterruptible power supply having a bypass power supply, and more particularly to a switching control device for switching to a bypass power supply without an instantaneous interruption when a failure occurs in a power supply.
[0002]
[Prior art]
FIG. 2 shows a conventional circuit configuration. The uninterruptible power supply main unit includes a converter 1 for converting AC power to DC power, an inverter 2 for obtaining an AC output of a constant voltage and a constant frequency using the output of the converter 1 as a DC power supply, and a power supply for the converter 1 when a power failure occurs. A main circuit is composed of a battery 3 serving as a backup DC power supply for the inverter 2 and an output transformer 4.
[0003]
The switching device is composed of a power supply switching contactor 5 for switching between a power supply main unit and a bypass power supply, and a semiconductor switch 7 for connecting a bypass power supply to a load 6 in parallel with the switching contactor 5.
[0004]
The control device 8 of the power supply device main body and the switching device has a control circuit for operating the converter 1 and the inverter 2 and generates gate signals to the gate circuits 1A and 2A. The control device 8 generates a switching signal for the power supply switching contactor 5 when a failure is detected in the failure detection circuit 8A, and also generates a gate signal for switching to the gate circuit 7A of the semiconductor switch 7.
[0005]
The control power supply 9 supplies a control power supply (for example, 24 volts) to the control device 8 and a control power supply to each of the gate circuits 1A, 2A, and 7A.
[0006]
The failure detection circuit 8A detects various failures of the power supply device main body and is used for switching control for uninterruptible power supply and protection of the device. For example, when detecting an overcurrent or overvoltage of the inverter 2, the failure detection circuit 8 </ b> A stops the inverter 2 and simultaneously generates a gate signal of the semiconductor switch 7 and a switching signal of the power switching contactor 5.
[0007]
In this switching, it takes about 0.1 second for the power supply switching contactor 5 to operate and switch to the bypass power supply side. During that time, the power is supplied to the load 6 through the semiconductor switch 7 without interruption. Then, after the contactor 5 is switched to the bypass power supply, power is supplied to the load through the contactor 5, and the semiconductor switch 7 is turned off.
[0008]
Similarly, to switch from the bypass power supply to the uninterruptible power supply main body side, the power supply main body is operated in synchronization with the bypass power supply, and the ON control of the semiconductor switch 7 and the switching control of the contactor 5 are performed. After turning off, the semiconductor switch 7 is turned off to obtain switching without instantaneous interruption.
[0009]
[Problems to be solved by the invention]
Switching of the instantaneous interruption between the power supply unit and the bypass power supply requires the switch 7 to be always turned on. However, in the conventional switching device, the on-control of the switch 7 may fail for the following reasons.
[0010]
(1) The power supply of the switch 7 is common to the control power supply of the apparatus main body. If the control power supply of the apparatus main body is lost due to a failure, the power supply of the switch 7 is also lost, so that the switch 7 cannot be turned on.
[0011]
(2) As a fault other than the loss of the control power supply of the apparatus main body, the switch 7 cannot be turned on even when a circuit portion that generates a gate signal for fault detection or switching of the fault detection circuit itself does not operate normally.
[0012]
As described above, in the conventional device, there is a possibility that the ON control of the semiconductor switch may fail due to the loss of the control power supply or the failure of the failure detection circuit. In this case, the switching without instantaneous interruption will fail.
[0013]
[Means for Solving the Problems]
The present invention generates a switching signal of a power switching contactor and a gate signal for turning on a semiconductor switch when a failure of a power supply main body is detected. Output voltage drop detection circuit which is generated when the voltage drop is detected, a switching signal and a gate signal are generated by a logical sum of the switch signal and the gate signal from the failure detection circuit or the output voltage drop detection circuit, A second control power supply is provided separately from the control power supply of the power supply body using the power supply power to the power supply to the power supply, and the second control power supply is used as a control power supply for the semiconductor switch and a power supply for the output voltage drop detection circuit. It is possible to perform instantaneous interruption switching without being affected by a failure of an apparatus main body or a failure of its control power supply. Further, when the second control power supply or the output voltage drop detection circuit or the like breaks down, the power supply from the power supply main body to the load can be continued and the instantaneous interruption can be switched because the control power supply on the main body side is sound. I do.
[0014]
Further, according to the present invention, by providing a control power supply monitoring circuit for obtaining an abnormality detection output when an abnormality occurs in the second control power supply, the control power supply is monitored, and the instantaneous interruption switching is ensured.
[0015]
Also, the present invention provides a semiconductor switch, an output voltage drop detection circuit, an OR circuit, and a second control power supply that can be separated from the uninterruptible power supply main body so that repair and inspection can be performed without stopping power supply to a load. Is possible.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a circuit diagram showing an embodiment of the present invention, and portions equivalent to those in FIG. 2 are denoted by the same reference numerals.
[0017]
The control power supply 10 is a second control power supply provided independently of the control power supply 9 of the apparatus main body, and supplies necessary power to the gate circuit 7A and the like. The power supply of the control power supply 10 is configured to take in the alternating current supplied to the load 6 through the switching contactor 5. In addition, an erroneous switching control is prevented by providing a configuration in which the control power supply output can be held even when the AC input is momentarily interrupted, specifically, for a moment longer than 0.1 seconds, which is longer than the switching time of the contactor 5.
[0018]
The output voltage drop detection circuit 11 uses the control power supply 10 as a power supply, and has a circuit for detecting a voltage drop of the power supply supplied to the load 6 from a detection voltage of the voltage detection transformer 12. A switching signal and a gate signal for ON control of the switch 7 are generated.
[0019]
OR circuits 13 and 14 are provided so as to obtain the logical sum of the switching signal and the gate signal from the failure detection circuit 8A and the output voltage drop detection circuit 11 on the apparatus main body side.
[0020]
The control power supply monitoring circuit 15 monitors a voltage drop of the control power supply 10, generates an abnormality detection output signal when the power supply is abnormal, and is used for maintenance and inspection as another abnormality monitoring signal of the apparatus main body.
[0021]
Note that the output (switching signal and gate signal) of the output voltage drop detection circuit 11 is turned off as an initialization period when the control power supply 10 rises, and erroneous power supply switching is prevented when the control power supply 10 rises.
[0022]
The switch 7 and its gate circuit 7A and the circuits 12 to 15 have a connection structure that can be removed even while the power is being supplied to the load 6, so that they can be repaired and maintained.
[0023]
In the present embodiment, the switching between the apparatus main body and the bypass power supply is performed when the failure is detected by the failure detection circuit 8A of the control device 8 or when the output voltage drop is detected by the output voltage drop detection circuit 11. You.
[0024]
Therefore, when the control power supply 9 is lost, there is no effect on the control power supply 10, and the instantaneous interruption switching from the detection circuit 11 side can be performed by the decrease of the output voltage of the apparatus main body.
[0025]
Conversely, when the control power supply 10 is lost, the power supply by the inverter 2 can be continued because there is no influence on the control power supply 9. While maintaining the power supply continuation state, the time required for repair of the control power supply 10 can be secured by the monitoring signal output by the control power supply monitoring circuit 15, and the circuits 7, 7A, 12 to 15 can be disconnected from the apparatus main body for repair. it can.
[0026]
Further, in the present embodiment, the switching between the contactor 5 and the semiconductor switch 7 can be performed by both the voltage drop detection circuit 11 and the failure detection circuit 8A, and the reliability of the instantaneous interruption switching is controlled by the switching control of the redundant configuration. Can be increased. For example, even when the failure detection circuit 8A fails to detect a failure in the apparatus main body, the detection circuit 11 can detect a decrease in the output of the inverter 2 and perform switching control.
[0027]
【The invention's effect】
As described above, according to the present invention, in addition to the conventional fault detection circuit, an output voltage drop detection circuit that detects a drop in the power supply voltage to the load is provided. A switching signal and a gate signal are generated by a logical sum of a switching signal and a gate signal, and a second control power supply is provided separately from a control power supply of a power supply main body using a power supply to a load as a power supply. Since the power supply is used as a control power supply for the semiconductor switch and a power supply for the output voltage drop detection circuit, instantaneous interruption switching can be performed without being affected by a failure of the power supply device main body or a failure of the control power supply. Further, when the second control power supply, the output voltage drop detection circuit, and the like fail, the control power supply on the main body side is sound, so that the power supply from the power supply main body to the load can be continued and the instantaneous interruption can be switched.
[0028]
In addition, according to the present invention, by providing a control power supply monitoring circuit that obtains an abnormality detection output when an abnormality occurs in the second control power supply, the control power supply can be monitored, and the reliability of instantaneous interruption switching can be improved. it can.
[0029]
Also, the present invention provides a semiconductor switch, an output voltage drop detection circuit, an OR circuit, and a second control power supply that can be separated from the uninterruptible power supply main body so that repair and inspection can be performed without stopping power supply to a load. Becomes possible.
[Brief description of the drawings]
FIG. 1 is a circuit diagram showing one embodiment of the present invention.
FIG. 2 is a conventional circuit diagram.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Converter 2 ... Inverter 3 ... Battery 5 ... Power switch contactor 6 ... Load 7 ... Semiconductor switch 8 ... Control device 8A ... Fault detection circuit 9 ... Control power supply 10 ... Second control power supply 11 ... Output voltage drop detection circuit 13 , 14 ... OR circuit 15 ... Control power supply monitoring circuit

Claims (3)

The uninterruptible power supply main unit and the bypass power supply are switched by the power switching contactor to supply power to the load, and during the switching operation of the power switching contactor, a semiconductor switch provided between the bypass power supply and the load is turned on to perform instantaneous switching. In the uninterruptible power supply that switches the disconnection,
A failure detection circuit that generates a switching signal for switching the power switching contactor to the bypass power supply side and a gate signal for turning on the semiconductor switch when detecting a failure of the power supply main body;
An output voltage drop detection circuit that generates a switching signal for switching the power supply switching contactor to the bypass power supply side and a gate signal for turning on the semiconductor switch when detecting a drop in the power supply voltage to the load;
A first OR circuit that takes a logical sum of a switching signal generated from the failure detection circuit and a switching signal generated from the output voltage drop detection circuit to be a switching signal of the power supply switching contactor;
A second OR circuit that takes a logical sum of a gate signal generated from the failure detection circuit and a gate signal generated from the output voltage drop detection circuit to be a gate signal for turning on the semiconductor switch;
A power supply for supplying power to the load and a second control power supply that is provided separately from the control power supply of the power supply main body and that is used as a power supply for controlling the semiconductor switch and a power supply for an output voltage drop detection circuit. Uninterruptible power supply. 2. The uninterruptible power supply according to claim 1, further comprising a control power supply monitoring circuit that obtains an abnormality detection output when an abnormality occurs in the second control power supply. 2. The uninterruptible power supply according to claim 1, wherein the semiconductor switch, the output voltage drop detection circuit, the OR circuit, and the second control power supply can be separated from the uninterruptible power supply main body.

Images