JPH11178243A - Uninterruptible power supply unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain an uninterruptible power supply unit which is capable of conducting switching from an inverter side to a commercial power source side for continuous power feeding to a load, even if a control power source becomes abnormal. SOLUTION: This uninterruptible power supply unit is provided with a control power source abnormality detecting circuit 901b, which detects failure of a control power source Vc and transmits a time failure detection signal backed-up by a capacitor, a command transmission control means 900 which outputs a switching set command based on either of a failure detection signal or a switching command, outputs the switching set command to a switching command generation circuit 800 based on the switching command when the control power source is normal, and outputs a switching reset command to the switching command generation circuit 800 when the switching command is off, and a switching command generation circuit control power source 905 which is used for supplying the power source of the switching command generation circuit 800, whereas the switching command generation circuit 800 outputs the on- command of a bypass side thyristor switch and an output switch based on a synchronizing signal, a switching set command signal, a switching reset command signal, and an output switch on-command.

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, and more particularly to a device that performs a switching operation even when a control power supply becomes abnormal.

[0002]

2. Description of the Related Art FIG. 10 has already been filed (Japanese Patent Application No. 9-6762).
FIG. 1 is a configuration diagram illustrating an uninterruptible power supply device. In FIG. 10, 1 is a commercial power supply, 2 is a converter for converting AC power output from the commercial power supply 1 to DC power, and 3 is an inverter for converting DC power output from the converter 2 to AC power having a predetermined frequency and a predetermined voltage. Reference numeral 4 denotes a battery for supplying DC power to the inverter 3 in place of the DC power output of the converter 2, and reference numeral 5 denotes a load receiving the output of the inverter 3.

Reference numeral 6 denotes a switching circuit for switching the power supply to the load 5 from the inverter 3 to the commercial power supply 1, an output switch 6a for connecting the output of the inverter 3 to the load 5, and the power supply to the load 5 from the inverter 3 to the commercial power supply. A bypass-side thyristor switch 6b for switching to 1; 800
Is a switching command generation circuit for generating a switching command to the switching circuit 6, and 700 is an abnormality detection circuit for the output switch.

Here, a detailed circuit of the switching command generating circuit 800 is shown in FIG. In FIG. 11, reference numeral 801 denotes a D-type flip-flop which latches data at an input terminal D at the rising edge of a switching instruction input to an input terminal T and outputs the data from an output terminal Q; 802a designates an output of the D-type flip-flop 801 and a switching instruction; 802b is a second AND circuit that inputs the output of the D-type flip-flop 801 to the negative input terminal and a switching command to the other input terminal, respectively, and 803 is a second AND circuit that inputs the switching command to the other input terminals.
An on-delay circuit that outputs an H signal with a predetermined delay when the input signal from 2b changes from L to H, and outputs an L signal without delay when the input signal changes from H to L;
Reference numeral 04 denotes an OR circuit that outputs the H signal delayed and output from the first AND circuit 802a or the ON delay circuit 803 as an example of a thyristor, and 802c receives a switching command of L and receives an output switch-on command. This is the third AND circuit that outputs the output switch-on command.

The output switch abnormality detection circuit 70
0 is shown in FIG. In FIG.
Reference numeral 04 denotes an auxiliary contact of the output switch 6a which operates in conjunction with ON / OFF of the output switch 6a.
04 is connected to the input terminal of the inverting circuit 702a,
The other end is grounded. 705 has a positive potential applied to one end, and the other end is connected to the input terminal of the inversion circuit 805a by the auxiliary contact 60.
1 is a current limiting resistor connected together with one end.

Reference numeral 703 denotes an output signal of the inverting circuit 702a being H
An on-delay circuit that delays and outputs the signal when the signal rises to a level, an inverting circuit 702b inverts the logic level of the on-delay circuit 703, an output switch-on command 701 is input to an input terminal D, and an inversion signal to an input terminal T The output signal of circuit 702b is input, and when the output signal rises from H to a level, a command to switch the level from H to a level is output from output terminal Q to switching command generating circuit 800.
Type flip-flop circuit.

Next, the operation will be described. Converter 2
Converts AC power supplied from the commercial power supply 1 into DC power, and charges the battery 4 while supplying DC power to the inverter 3. Inverter 3 converts DC power supplied from converter 2 to AC power, and supplies AC power to load 5. In this state, if the commercial power supply 1 fails,
The inverter 3 is supplied with DC power from the battery 4,
Continue supplying power to the load 5 without interruption. Further, when an abnormality or an overcurrent occurs in the output voltage of the inverter 3, the abnormality is detected immediately, and the abnormality is given to the switching command generation circuit 800, and the power supply to the load 5 is switched from the inverter 3 to the commercial power supply 1. Next, the switching operation will be described.

That is, in the configuration of the switching command generation circuit 800 shown in FIG.
00, when the input to the input terminal T of the D-type flip-flop 801 changes from the L level to the H-level, and the output voltage of the inverter 3 is synchronized with the commercial power supply 1, The output from the output terminal Q becomes H level, and if asynchronous, it becomes L level. In other words, when they are synchronized, the output of the AND circuit 802c which gives the ON command of the output switch 6a becomes L level and the output switch 6a turns OFF, and at the same time, the OR circuit 804 which gives the ON command of the bypass thyristor switch 6b Output becomes H level and the bypass-side thyristor switch 6
b turns on and can be switched without interruption. On the other hand, when the output voltage of the inverter 3 is asynchronous with the commercial power supply 1,
For example, when the output voltage of the inverter 3 and the voltage of the commercial power supply 1 are instantaneously switched with a phase difference of 180 degrees, the load 5 may be destroyed.
After the time set in step 6, the bypass-side thyristor switch 6b
Is turned on, the power supply is switched after an instantaneous interruption, and depending on the load 5, the operation may be continued in some cases.

Next, the operation of the output switch abnormality detecting circuit 700 having the configuration shown in FIG. 12 will be described with reference to the waveforms of the respective parts shown in FIG. As shown in FIG. 13, the waveform at point a in FIG.
In the off state, when the output switch 6a is turned on, the auxiliary contact 704 is turned on in conjunction with the output switch 6a.
If the output switch 6a is turned off after the L level is repeated, the auxiliary contact 7
04 turns off and becomes H level. As shown in FIG. 13, the waveform at the point b in FIG. 12 is inverted logic of the waveform at the point a by the inverting circuit 702a. The waveform at the point c is set to the H level after a delay time for eliminating the chattering of the auxiliary contact 704 by the on-delay circuit 703, and the waveform at the point d is inverted logic of the waveform at the point c by the inverting circuit 702b.

Here, the output switch ON command is output when the output switch 6a is ON.
Is abnormally turned off, the auxiliary contact 70
4 also turns off. At this time, the d-point waveform changes from the L level to the H level, and the D-type flip-flop 701 latches the H level of the output switch-on command at its rising edge, and gives an output switch abnormality as a switching command of the switching command generating circuit 800, Since the power supply from the inverter 3 can be instantaneously switched to the commercial power supply 1, the output switch 6a
Can be continued to supply power to the load 5 even if the power supply becomes abnormal.

[0011]

Since the conventional uninterruptible power supply is constructed as described above, it supplies a switching command, a synchronizing signal or an output switch on command to the switching command generating circuit 800 during power supply to the inverter. However, when the control means (not shown) or its control power supply becomes abnormal, the switching command cannot be output and the power supply to the load 5 is stopped.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem. Even if the control means or the control power supply becomes abnormal, the inverter switches from the inverter side to the commercial power supply side by the abnormality signal to supply power to the load. It is an object of the present invention to obtain an uninterruptible power supply capable of continuously supplying power to the power supply.

[0013]

An uninterruptible power supply according to the present invention comprises a commercial power supply, a converter for converting AC power output from the commercial power supply to DC power, and a converter for converting output power of the converter to a predetermined frequency. An inverter for converting voltage into AC power, an output switch provided between the inverter and the load, and a bypass-side thyristor switch provided between the commercial power supply and the load, wherein the output switch or the thyristor is provided. A switching circuit for switching power supply to a load to the commercial power supply or the inverter based on a switch on command; and a switching command when the output switch is on based on an output switch on command. From low level to high level, the output voltage of the inverter synchronizes with the commercial power supply and the synchronization signal goes high. In the case of a bell, the output switch is turned off, and at the same time, the power supply to the load is switched from the inverter to the commercial power supply by issuing an on command of the bypass thyristor switch, and the output voltage of the inverter is asynchronous with the commercial power supply. And a switching command generating circuit that issues an ON command for the bypass thyristor switch after a set time to switch power supply to the load from the inverter to the commercial power source when the synchronization signal is at a low level. The power supply device includes a control power supply abnormality detection circuit that detects an abnormality of the control power supply backed up by the capacitor and sends a time abnormality detection signal backed up by the capacitor, and the control power supply abnormality detection circuit outputs any of the abnormality detection signal and the switching command. Output a switching set command based on the Command sending control means for outputting a switching set command to the switching command generating circuit based on the switching command when the power supply is normal, and outputting a switching reset command to the switching command generating circuit when the switching command is off; A switching command generating circuit control power supply for supplying power to the switching command generating circuit, wherein the switching command generating circuit includes the synchronous signal, the switching set command signal, the switching reset command signal, and the output switch. An on-command for the bypass-side thyristor switch and the output switch is output based on the on-command.

Further, the command transmission control means further comprises an off-delay circuit for delaying a change of the switching set command from on to off.

Further, the command transmission control means further comprises delay means for delaying the synchronization signal and transmitting the same to the switching command generation circuit.

When the synchronization signal changes from the asynchronous state to the synchronous state, the delay means sends the synchronous signal to the switching command generating circuit without delay, and the synchronous signal changes from the synchronous state to the asynchronous state. When this happens, the synchronization signal is delayed and sent to the switching command generation circuit.

Further, the delay means transmits the synchronization signal to the switching command generation circuit without delay when the synchronous state is changed from the synchronous state to the asynchronous state when the synchronous control is abnormal.

A control power supply abnormality detection circuit for the switching command generation circuit for detecting an abnormality of the control power supply for the switching command generation circuit, and an output signal of the control power supply abnormality detection circuit for the switching command generation circuit, for controlling the bypass thyristor switch. A second switching command generating circuit for outputting an ON command, wherein the thyristor ON command output of the switching command generating circuit is matched with the output of the second switching command generating circuit.

An uninterruptible power supply according to another invention is
A commercial power supply, a converter that converts AC power output from the commercial power supply into DC power, an inverter that converts output power of the converter into AC power having a predetermined frequency and a predetermined voltage, and a power supply provided between the inverter and the load. And a bypass-side thyristor switch provided between the commercial power supply and the load, and supplies power to the load to the commercial power supply or the inverter based on an ON command of the output switch or the thyristor switch. A switching circuit for switching, and when the ON command is issued to the output switch based on the output switch ON command, the switching command changes from a low level to a high level, and the output voltage of the inverter is synchronized with the commercial power supply. When the synchronization signal is at a high level, the output switch is turned off and When the power supply to the load is switched from the inverter to the commercial power supply by issuing an ON command for the side thyristor switch, and when the output voltage of the inverter is asynchronous with the commercial power supply and the synchronization signal is at a low level, An uninterruptible power supply having a switching command generating circuit for switching the power supply to the load from the inverter to the commercial power by issuing an ON command for the bypass-side thyristor switch, wherein the synchronous signal, the switching command, and the output A microprocessor for outputting a switch-on command, a microprocessor abnormality detection circuit for detecting an abnormality of the microprocessor, a delay circuit for delaying the synchronization signal output from the microprocessor, and a synchronization signal via the delay circuit According to the abnormality detection signal of the microprocessor Latch means for switching, a new synchronization signal based on the logical sum output of the synchronization signal and the output of the latch means, a new switching command based on the logical sum output of the switching command and the abnormality detection signal, and the output Command transmission control means for outputting a new output switch-on command to the switching command generation circuit based on a logical product output of the switch-on command and the abnormality detection signal, wherein the switching command generation circuit includes the command transmission control And outputting a turn-on command for the bypass-side thyristor switch and a turn-on command for the output switch based on a synchronization signal, a switching command, and an output switch on command signal output from the means.

Further, the command transmission control means further comprises an off-delay circuit for delaying a change of the output switch on command from on to off.

Further, the command transmission control means further comprises a delay circuit for delaying a change of the output switch ON command from OFF to ON.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a configuration diagram showing only a main part of the uninterruptible power supply according to the first embodiment. In the first embodiment, in the overall configuration shown in FIG. 10, power is supplied to load 5 by switching from inverter power supply to commercial power supply to switch command generation circuit 800 even if control power supply Vc becomes abnormal. A command transmission control means 900 for continuing is provided.

That is, the command transmission control means 900
Are the control power supply abnormality detection circuit 901b and the OR circuit 901
a control power supply monitoring circuit 901, a diode 902, a capacitor 903, an inverting circuit 904, and an RS flip-flop 906.
1b, the abnormality of the control power supply Vc backed up by the capacitor 903 is detected,
And outputs a switching set command based on either the abnormality detection signal or the switching command, and generates a switching command based on the switching command when the control power supply Vc is normal. Circuit 8
00, and outputs a switching reset command to the switching command generating circuit 800 when the switching command is OFF. The switching command generating circuit 800 includes a synchronization signal, a switching set command signal, and a switching reset command. A command to turn on the bypass thyristor switch 6b and the output switch 6a is output based on the signal and the output switch ON command. Reference numeral 905 denotes a control power supply for the switching command generation circuit, and Vc denotes a control power supply of a control unit that outputs a synchronization signal, a switching command, and an output switch-on command. The switching command generation circuit 800 has the same configuration as the conventional example shown in FIG.

Next, the operation of the above embodiment will be described with reference to FIG. The switching command generating circuit 800 changes the output of the RS flip-flop 906 to H in response to a switching set command input, performs a switching operation, and performs RS switching in response to a switching reset command.
The output of the flip-flop 906 is set to L to cancel the switching operation. The power supply of the switching command generation circuit 800 is
It is supplied by a control power supply 905 for the switching command generation circuit which is a power supply different from the control power supply Vc.
Even if c becomes abnormal, the switching operation can be performed when a signal is given to the switching set command input of the switching command generating circuit 800.

The control power supply monitoring circuit 901 has a control power supply Vc
Power is supplied through the diode 902,
It is backed up by the capacitor 903. Therefore, even if the control power supply Vc becomes abnormal, the control power supply monitoring circuit 901 can detect the abnormality of the control power supply Vc and transmit a signal based on the energy stored in the capacitor 903. The capacity of the capacitor 903 only needs to be large enough to allow the control power supply monitoring circuit 901 to output a signal for a time during which the input of the D-type flip-flop 801 and the input of the RS flip-flop 906 of the switching command generation circuit 800 accept the signal.

Here, when the control power supply Vc becomes abnormal, the control power supply monitoring circuit 901 detects that the control power supply abnormality detection circuit 901b detects the abnormality of the control power supply Vc,
A switching set command is output to the switching command generation circuit 800 as a one-shot pulse of the time of the energy backed up in the capacitor 903 via 01a. At this time, the switching reset command of the switching command generating circuit 800 connected to the output of the OR circuit 901a via the inverting circuit 904 discharges all the energy stored in the capacitor 903, and the output of the OR circuit 901a changes. Even if H cannot be output, the inversion circuit 904 cannot output H because the control power supply Vc is lost, and remains at L. The D-type flip-flop 8 is switched by this switching set command.
01, the output Q of the D-type flip-flop 801 outputs H if the synchronization signal as the D input is synchronous, and L if the synchronization signal is asynchronous.
Is output to the subsequent circuit as a synchronous or asynchronous switching condition. The output of the RS flip-flop 906 can latch the switching command by the switching set command and perform the switching operation. Even if the power supply Vc becomes abnormal, the power can be continuously supplied to the load by switching from the inverter power supply to the commercial power supply.

Embodiment 2 FIG. Next, FIG.
In FIG. 2, portions corresponding to those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted. The difference from the first embodiment is that an off-delay circuit 921 that delays the change by a predetermined time and outputs it when the signal of the switching set command changes from H to L is added to the command transmission control means 900. Is the same as in the first embodiment.

In FIG. 2, when the control power supply Vc becomes abnormal, the control power supply Vc monitoring circuit
And outputs a one-shot pulse for the time of the energy stored in the memory. The voltage of the capacitor 903 discharges and decreases as the control power supply monitoring circuit 901 operates. Therefore, when the capacitance of the capacitor 903 is large, the voltage level of the one-shot pulse gradually decreases. Therefore, the T input of the D-type flip-flop 801 and the S input of the RS flip-flop 906 oscillate when the input signal gently crosses the threshold. Some are damaged. Therefore, once the signal goes high, the switch set command is sent to the T input of the D-type flip-flop 801 and the RS flip-flop 906 via the off-delay circuit 921 which requires a predetermined time period to go low.
To the S input, it is possible to prevent the IC from being damaged due to dull input signals.

With such a configuration, even if the capacity of the backup capacitor 903 of the control power supply Vc becomes large, the IC can be switched from the inverter power supply to the commercial power supply due to the abnormality of the control power supply Vc without damaging the IC. it can.

Embodiment 3 Next, FIG.
In FIG. 3, portions corresponding to those in FIG. 2 are denoted by the same reference numerals, and detailed description thereof will be omitted. The difference from the second embodiment is that a resistor 931 and a capacitor 932 are added as delay means for delaying the synchronization signal of the switching command generation circuit 800, and the other points are the same as the second embodiment.

In FIG. 3, when the control power supply Vc suddenly becomes 0 V due to a short circuit or the like, the synchronous signal of the switching command generating circuit 800 suddenly becomes L level indicating the asynchronous state even in the synchronous state. The asynchronous switching operation is performed by this signal. Therefore, the synchronization signal is delayed by the resistor 931 and the capacitor 932, so that the synchronization / asynchronization state just before is maintained, so that the switching operation according to the synchronization / asynchronization state can be performed.

With such a configuration, even when the control power supply Vc suddenly becomes 0 V due to a short circuit or the like, the synchronous / asynchronous state is maintained slightly before, so that switching according to the synchronous / asynchronous state is performed. It can be carried out.

Embodiment 4 FIG. Next, FIG.
4, parts corresponding to those in FIG. 3 are denoted by the same reference numerals, and detailed description thereof will be omitted. The difference from the third embodiment is that the synchronization signal of the switching command generation circuit 800 is synchronized / synchronized so that there is no delay from the asynchronous state to the synchronous state and there is a delay from the synchronous state to the asynchronous state.
The third embodiment is the same as the third embodiment except that a diode 941 is added in parallel with the resistor 931 of the delay unit for maintaining the asynchronous state.

The asynchronous switching operation is performed by the on-delay circuit 80
Since the switching is performed with a momentary interruption for the time set in 3, when the output of the inverter 3 is synchronized with the commercial power supply 1, it is preferable to perform the synchronous switching. However, the resistor 932
And the capacitor 921 delays the synchronization command signal. When a switching command is generated at the moment when the synchronization state is changed from the asynchronous state, the D input of the D-type flip-flop 801 is set by the delay means of the resistor 931 and the capacitor 932. Since the state is still in the asynchronous state, the asynchronous switching operation is performed. Therefore, the diode 941 is connected in parallel to the resistor 931 for maintaining the synchronous / asynchronous state so that the synchronous signal has no delay from the asynchronous state to the synchronous state and has a delay from the synchronous state to the asynchronous state. In the synchronous state, the synchronous switching operation can always be performed.

With such a configuration, the detection from the asynchronous state to the synchronous state is performed without delay, so that the synchronous switching operation can be always performed in the synchronous state.

Embodiment 5 Next, FIG.
In FIG. 5, portions corresponding to those in FIG. 4 are denoted by the same reference numerals, and detailed description thereof will be omitted. The difference from the fourth embodiment is that the delay means outputs L when the input is at the H level and outputs an open state when the input is at the L level, and detects an abnormality in the synchronization control circuit. Synchronous control abnormality detection circuit 952 and AND circuit 9
53 is added, and the rest is the same as the fourth embodiment.

In FIG. 5, when the synchronous control circuit becomes abnormal, the inverter 3 cannot synchronize with the commercial power supply 1 and enters an asynchronous state. At this time, if any abnormality occurs, an asynchronous switching operation must be performed. Then, when the synchronous control abnormality detecting circuit 952 detects an abnormality of a synchronous control circuit (not shown), if the state is asynchronous at that time, the AND circuit 952 outputs H, and the open collector 951 outputs the output of the AND circuit 952. If it is H, the output is made L and the D input of the D-type flip-flop 801 is immediately put in an asynchronous state, so that an asynchronous switching operation can be performed.

By adopting such a configuration, even when the synchronous control is abnormal, the detection from the synchronous state to the asynchronous state is performed without delay, so that the asynchronous switching operation can always be performed in the asynchronous state. .

Embodiment 6 FIG. Next, FIG.
In FIG. 6, portions corresponding to those in FIG. 5 are denoted by the same reference numerals, and detailed description thereof will be omitted. The difference from the fifth embodiment is that the control power supply 905
Control power supply abnormality detection circuit 967 for detecting a failure of the switch and outputting an abnormality signal, and a second switching instruction generation circuit 960 for performing a switching operation based on the output signal of the control power supply abnormality detection circuit 967 for the switching instruction generation circuit. D-type flip-flop 961 and AND circuits 962a and 962
b, that an on-delay circuit 963, an OR circuit 964, and diodes 965 and 966 for passing the outputs of the OR circuit 964 and the OR circuit 804 are added.
Others are the same as the fifth embodiment.

In FIG. 6, when the control power supply 905 for the switching command generation circuit becomes abnormal, the output of the AND circuit 802C becomes L level, the output switch 6a is turned off, and the power supply to the load 5 is stopped. Therefore, an abnormality of the control power supply 905 for the switching command generation circuit is detected by the control power supply abnormality detection circuit 967 for the switching command generation circuit, and the power supply is controlled by the output signal of the control power supply abnormality detection circuit 967 for the switching command generation circuit. By performing the switching operation by the second switching command generating circuit 960 supplied from the power supply, the switching from the inverter power supply to the commercial power supply can be performed without an instantaneous interruption, and the power supply to the load 5 can be continued.

With such a configuration, even if the control power supply for the switching command generation circuit becomes abnormal, it is possible to switch from the inverter power supply to the commercial power supply without an instantaneous interruption.

Embodiment 7 Next, FIG.
In FIG. 7, portions corresponding to those of the conventional example shown in FIG. 11 are denoted by the same reference numerals, and detailed description thereof will be omitted. Microprocessor 976 for generating synchronization signal, switching command, output switch on command, microprocessor 9
A microprocessor abnormality detection circuit 977 for detecting an abnormality of 76 and outputting an abnormality signal;
D type latching the output signal of the delay means composed of the resistor 975 and the capacitor 974 and the resistor 975 and the capacitor 974 as the delay means for delaying the synchronization signal which is the output signal of the microprocessor with the output signal of the microprocessor abnormality detection circuit 977 Flip-flop 971, OR circuits 973a and 973b, AND circuit 972 as command transmission control means
It has.

In FIG. 7, a synchronization signal, a switching command, an output switch-on command, and the like are sometimes calculated and detected by using a microprocessor 976, and a signal is output.
In this case, if the microprocessor 976 becomes abnormal, it is not known what output each output signal sends, and the inverter 3 may not continue to supply power to the load 5. Thus, the microprocessor abnormality detection circuit 977 detects the abnormality of the microprocessor 976 at high speed, and performs the switching operation based on the output signal of the microprocessor abnormality detection circuit 977. At this time, the synchronization signal which is the output signal of the microprocessor 976 may output a signal indicating the asynchronous state due to the abnormality of the microprocessor 976 while the synchronization signal is in the synchronous state. By maintaining the synchronous / asynchronous state by the resistor 975 and the capacitor 974 during the time of detecting the abnormality, the switching operation according to the synchronous / asynchronous state can be performed.

With this configuration, even if the microprocessor 976 becomes abnormal, it is possible to switch from inverter power supply to commercial power supply.

Embodiment 8 FIG. Next, FIG.
In FIG. 8, portions corresponding to those in FIG. 7 are denoted by the same reference numerals, and detailed description thereof will be omitted. The difference from the seventh embodiment is that a resistor 981, a capacitor 982, and a diode 983 are added as an off-delay circuit to delay the change of the output switch-on command signal of the switching command generation circuit 800 from on to off. Yes, the rest is the same as the seventh embodiment.

In FIG. 8, when the detection time of the microprocessor abnormality detection circuit 977 is late, the microprocessor 976 becomes abnormal, and even if the output switch on command is output to the off side, the microprocessor abnormality detection circuit 9
Since it takes time for the 77 to detect the abnormality of the microprocessor 976, only the output switch 6a is turned off and the load 5
Power supply to is stopped. Therefore, the off-delay is performed by the resistor 981, the capacitor 982, and the diode 983 so as to be turned off with a delay corresponding to the detection time of the microprocessor abnormality detection circuit 977, regardless of the detection time limit of the microprocessor abnormality detection circuit 977. The switching operation can be performed by detecting an abnormality of the microprocessor 976.

With this configuration, the switching operation can be performed by detecting the abnormality of the microprocessor 976 irrespective of the microprocessor abnormality detection time limit.

Embodiment 9 FIG. Next, FIG.
In FIG. 9, portions corresponding to those in FIG. 8 are denoted by the same reference numerals, and detailed description thereof will be omitted. The difference from the eighth embodiment is that a diode 983 is eliminated to constitute a delay circuit for delaying the change of the output switch ON command from OFF to ON, and the other configuration is the same as that of the eighth embodiment. .

In FIG. 9, if the output switch-on command is the same as the time period provided for turning off from on for the person who turns on from off, the delay circuit (delay circuit) for the output switch-on command may be a resistor. 981 and capacitor 9
82 alone.

With such a configuration, a diode is not required in the delay circuit for the output switch-on command of the switching command generation circuit 800, so that the circuit is inexpensive and simple.

[0051]

As described above, according to the uninterruptible power supply of the present invention, the commercial power supply, the converter for converting the AC power output from the commercial power supply to the DC power, and the output power of the converter An inverter that converts the AC power to a predetermined frequency and a predetermined voltage, an output switch provided between the inverter and the load, and a bypass-side thyristor switch provided between the commercial power supply and the load;
A switching circuit that switches power supply to a load to the commercial power supply or the inverter based on the ON command of the output switch or the thyristor switch, and a switching circuit that issues an ON command to the output switch based on the output switch ON command. When the switching command changes from a low level to a high level, the output voltage of the inverter is synchronized with the commercial power supply and the synchronizing signal is at a high level, the output switch is turned off, and at the same time, the bypass thyristor switch is turned on. To switch the power supply to the load from the inverter to the commercial power supply, and when the output voltage of the inverter is asynchronous with the commercial power supply and the synchronization signal is at a low level, the bypass-side thyristor switch is turned on after a set time. Issue a command to supply power to the load from the inverter In the uninterruptible power supply having a switching command generating circuit adapted to switch to a power supply for use, a control power supply abnormality detecting an abnormality of the control power supply backed up by the capacitor and transmitting a time abnormality detection signal backed up by the capacitor. A detection circuit for outputting a switching set command based on either the abnormality detection signal or the switching command, and when the control power supply is normal, a switching set command to the switching command generating circuit based on the switching command. And a command transmission control means for outputting a switching reset command to the switching command generation circuit when the switching command is off, and a control power supply for the switching command generation circuit for supplying power to the switching command generation circuit Wherein the switching command generation circuit includes: the synchronization signal, the switching set command signal, and the switching reset command. The on-command for the bypass thyristor switch and the output switch is output based on the signal and the output switch on command. To continue supplying power to the load.

Further, the command transmission control means further includes an off-delay circuit for delaying a change of the switching set command from on to off, so that even if the capacity of the backup capacitor of the control power supply becomes large, the IC is controlled. It is possible to switch from the inverter power supply to the commercial power supply due to an abnormality in the control power without damage.

Further, the command transmission control means further includes delay means for delaying the synchronization signal and transmitting it to the switching command generation circuit. Therefore, even if the control power supply suddenly becomes 0 V due to a short circuit or the like, By maintaining the synchronous / asynchronous state immediately before, switching according to the synchronous / asynchronous state can be performed.

When the synchronous signal changes from the asynchronous state to the synchronous state, the delay means sends the synchronous signal to the switching command generating circuit without delay when the synchronous signal changes from the synchronous state to the asynchronous state. In such a case, the synchronization signal is delayed and sent to the switching command generating circuit. Therefore, the detection from the asynchronous state to the synchronous state is performed without delay, so that the synchronous switching operation is always performed in the synchronous state. be able to.

Further, when the synchronous control is abnormal, the delay means sends the synchronous signal to the switching command generating circuit without delay when the synchronous state changes to the asynchronous state. Also, by performing the detection from the synchronous state to the asynchronous state without delay, the asynchronous switching operation can always be performed in the asynchronous state.

Also, a control power supply abnormality detection circuit for the switching command generation circuit for detecting an abnormality of the control power supply for the switching command generation circuit, and an output signal of the control power supply abnormality detection circuit for the switching command generation circuit, for controlling the bypass thyristor switch. A second switching command generating circuit for outputting an ON command, wherein the thyristor ON command output of the switching command generating circuit is matched with the output of the second switching command generating circuit. Can be switched from inverter power supply to commercial power supply without interruption.

According to another aspect of the present invention, there is provided an uninterruptible power supply, comprising: a commercial power supply; a converter for converting AC power output from the commercial power supply into DC power; And an output switch provided between the inverter and the load, and a bypass thyristor switch provided between the commercial power supply and the load, wherein the output switch or the thyristor switch is provided. A switching circuit for switching the power supply to the load to the commercial power supply or the inverter based on the ON command of the switch, and a switching command low when the ON command is issued to the output switch based on the output switch ON command. From high level to high level, the output voltage of the inverter is synchronized with the commercial power supply, and the synchronization signal is high level. In this case, the output switch is turned off, and at the same time, the power supply to the load is switched from the inverter to the commercial power supply by issuing an ON command of the bypass-side thyristor switch, and the output voltage of the inverter is asynchronous with the commercial power supply. An uninterruptible power supply comprising: a switching command generating circuit for issuing an ON command for the bypass thyristor switch after a set time when the synchronization signal is at a low level, and switching power supply to a load from the inverter to the commercial power supply. A microprocessor that outputs the synchronization signal, the switching instruction, and the output switch-on instruction; a microprocessor abnormality detection circuit that detects an abnormality of the microprocessor; and a delay unit that delays the synchronization signal output from the microprocessor. Through the delay circuit Latch means for latching the synchronized signal by the abnormality detection signal of the microprocessor; a new synchronization signal based on the logical sum output of the synchronization signal and the output of the latch means; and the logical sum of the switching command and the abnormality detection signal A new switch command based on the output, and command transmission control means for outputting a new output switch-on command based on a logical product output of the output switch-on command and the abnormality detection signal to the switch command generating circuit, The switching command generation circuit outputs an ON command for the bypass-side thyristor switch and an ON command for the output switch based on a synchronization signal output from the command transmission control means, a switching command, and an output switch ON command signal. Therefore, even if the microprocessor becomes abnormal, it is possible to switch from inverter power supply to commercial power supply. Wear.

Further, the command transmission control means further includes an off-delay circuit for delaying the change of the output switch-on command from on to off, so that the microprocessor abnormality can be detected regardless of the microprocessor abnormality detection time limit. Upon detection, a switching operation can be performed.

Since the command transmission control means further includes a delay circuit for delaying the change of the output switch ON command from OFF to ON, a diode is provided in the output switch ON command delay circuit of the switching command generation circuit. Since it is not necessary, the circuit is inexpensive and simple.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a first embodiment of the present invention.

FIG. 2 is a circuit diagram showing a second embodiment of the present invention.

FIG. 3 is a circuit diagram showing a third embodiment of the present invention.

FIG. 4 is a circuit diagram showing a fourth embodiment of the present invention.

FIG. 5 is a circuit diagram showing a fifth embodiment of the present invention.

FIG. 6 is a circuit diagram showing a sixth embodiment of the present invention.

FIG. 7 is a circuit diagram showing a seventh embodiment of the present invention.

FIG. 8 is a circuit diagram showing an eighth embodiment of the present invention.

FIG. 9 is a circuit diagram showing a ninth embodiment of the present invention.

FIG. 10 is a circuit diagram showing a configuration of a conventional example.

FIG. 11 is a circuit diagram showing details of a switching command generation circuit.

FIG. 12 is a circuit diagram showing details of an output switch abnormality detection circuit.

FIG. 13 is a waveform diagram of each part of the output switch abnormality detection circuit.

[Explanation of symbols]

1 Commercial power supply, 2 converters, 3 inverters, 5
Load, 6 switching circuit, 6a output switch, 6b bypass thyristor switch, 700 output switch abnormality detection circuit, 800 switching command generation circuit, 900 command transmission control means, 901 control power supply monitoring circuit, 901a OR circuit, 901b control power supply abnormality Detection circuit, 902
Diode, 903 capacitor, 904 inverting circuit,
905 Switching command generation circuit, 906 RS flip-flop, 921 off delay circuit, 931 resistor, 9
32 capacitor, 941 diode, 951 open collector, 952 synchronization control abnormality detection circuit, 953
AND circuit, 967 control power supply abnormality detection circuit for switching command generation circuit, 960 second switching command generation circuit, 961
D flip-flop, 962a, 962b AND circuit, 963 ON delay circuit, 964 OR circuit,
965,966 diode, 971 D flip-flop, 972 AND circuit, 973 AND circuit, 97
4 capacitor, 975 resistance, 976 microprocessor, 977 microprocessor abnormality detection circuit, 9
81 resistors, 982 capacitors, 983 diodes.

Claims (9)

[Claims] 1. A commercial power supply, a converter that converts AC power output from the commercial power supply into DC power, an inverter that converts output power of the converter into AC power having a predetermined frequency and a predetermined voltage, and the inverter and a load. And a bypass thyristor switch provided between the commercial power supply and the load, and supplies power to the load based on the ON command of the output switch or the thyristor switch. A switching circuit for switching to the power supply or the inverter; and a state in which an ON command is issued to the output switch based on the output switch ON command, the switching command changes from a low level to a high level, and the output voltage of the inverter is reduced. The same as turning off the output switch when the synchronization signal is at the high level in synchronization with the commercial power supply At the same time, the power supply to the load is switched from the inverter to the commercial power supply by issuing an ON command of the bypass-side thyristor switch, and the setting is performed when the output voltage of the inverter is asynchronous with the commercial power supply and the synchronization signal is at a low level. A control power supply backed up by a capacitor in an uninterruptible power supply having a switching command generation circuit for issuing an ON command of the bypass thyristor switch after a time to switch the power supply to the load from the inverter to the commercial power supply. Has a control power supply abnormality detection circuit that detects abnormality of the power supply and sends a time abnormality detection signal backed up by the capacitor.
A switching set command is output based on either the abnormality detection signal or the switching command, and when the control power supply is normal, a switching set command is output to the switching command generating circuit based on the switching command, and Command switching control means for outputting a switching reset command to the switching command generating circuit when the switching command is off; and a switching command generating circuit control power supply for supplying power to the switching command generating circuit. The command generation circuit outputs an ON command for the bypass thyristor switch and the output switch based on the synchronization signal, the switching set command signal, the switching reset command signal, and the output switch ON command. Uninterruptible power system. 2. The uninterruptible power supply according to claim 1, wherein said command transmission control means further comprises an off-delay circuit for delaying a change of said switching set command from on to off. 3. The uninterruptible power supply according to claim 1, wherein said command transmission control means further comprises delay means for delaying said synchronization signal and transmitting it to said switching command generation circuit. 4. The delay means sends the synchronous signal to the switching command generating circuit without delay when the synchronous signal changes from the asynchronous state to the synchronous state, and changes the synchronous signal from the synchronous state to the asynchronous state. 4. The uninterruptible power supply according to claim 3, wherein the synchronization signal is delayed and transmitted to the switching command generation circuit. 5. The switching circuit according to claim 4, wherein said delay means sends said synchronization signal to said switching command generation circuit without delay when a synchronization state is changed from a synchronization state to an asynchronous state. Blackout power supply. 6. A control power supply abnormality detection circuit for a switching instruction generation circuit for detecting an abnormality of the control power supply for the switching instruction generation circuit, and a control signal abnormality detection circuit for the bypass side thyristor switch based on an output signal of the control power supply abnormality detection circuit for the switching instruction generation circuit. 6. A second switching command generating circuit for outputting an ON command, wherein a thyristor ON command output of the switching command generating circuit is matched with an output of the second switching command generating circuit. The uninterruptible power supply according to any one of the above. 7. A commercial power supply, a converter for converting AC power output from the commercial power supply to DC power, an inverter for converting output power of the converter to AC power having a predetermined frequency and a predetermined voltage, the inverter and the load And a bypass thyristor switch provided between the commercial power supply and the load, and supplies power to the load based on the ON command of the output switch or the thyristor switch. A switching circuit for switching to the power supply or the inverter; and a state in which an ON command is issued to the output switch based on the output switch ON command, the switching command changes from a low level to a high level, and the output voltage of the inverter is reduced. When the output switch is turned off when the synchronization signal is at the high level in synchronization with the commercial power supply, At the same time, the power supply to the load is switched from the inverter to the commercial power supply by issuing an ON command of the bypass-side thyristor switch, and the setting is performed when the output voltage of the inverter is asynchronous with the commercial power supply and the synchronization signal is at a low level. A switching command generating circuit configured to issue an on-command of the bypass-side thyristor switch after a lapse of time to switch the power supply to the load from the inverter to the commercial power supply. A microprocessor that outputs the output switch-on command; a microprocessor abnormality detection circuit that detects an abnormality of the microprocessor; a delay circuit that delays the synchronization signal output from the microprocessor; The synchronization signal Latch means for latching with a normal detection signal, a new synchronization signal based on the logical sum output of the synchronization signal and the output of the latch means, a new switching command based on the logical sum output of the switching command and the abnormality detection signal, And command transmission control means for outputting a new output switch-on command to the switching command generating circuit based on a logical product output of the output switch-on command and the abnormality detection signal, wherein the switching command generating circuit comprises: An uninterruptible power supply device for outputting an ON command for the bypass thyristor switch and an ON command for the output switch based on a synchronization signal, a switching command, and an output switch ON command signal output from the command transmission control means. 8. The uninterruptible power supply according to claim 7, wherein said command transmission control means further comprises an off-delay circuit for delaying a change of said output switch on command from on to off. 9. The uninterruptible power supply according to claim 7, wherein said command transmission control means further comprises a delay circuit for delaying a change of said output switch ON command from OFF to ON.