JPH08172734A - Method of controlling uninterruptible power-supply apparatus - Google Patents

Abstract

PURPOSE: To obtain a control method in which a power supply to a load can be continued without momentary interruption by a method wherein, when a failure is occurred in a semiconductor switch during a power supply from a commercial power supply, the power supply is changed over to a power supply from a multifunctional inverter without momentary interruption so as to be returned to the power supply from the commertial power supply via a bypass contactor when a commercial voltage exists. CONSTITUTION: When a failure is occurred in a semiconductor switch 3 during a power supply to a load 23 from a commercial power supply 21, a semiconductor-switch-failure detection means 31 detects the failure of the semiconductor switch 3 so as to output a failure signal 61. A changeover control circuit 31, on the basis of the failure signal, changes over to a power supply from a battery 22 by a multifunctional inverter 5 without momentary interruption, and it judges whether the commercial voltage of the commercial power supply 21 exists or not. When the voltage exists, a bypass contactor 4 is turned on so as to be returned to the power supply from the commerical power supply 21 via the bypass contactor 4. Thereby, it is possible to continue the power supply to the load 23 without momentary interruption.

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 device which is constantly supplied with power from a commercial power source and supplies power to a load, and particularly when a semiconductor switch for supplying / interrupting commercial power fails. The present invention relates to a control method of an uninterruptible power supply device that can supply power to a power supply without instantaneous interruption. Further, the present invention relates to a control method of an uninterruptible power supply for preventing an inrush current from a commercial power supply when starting the uninterruptible power supply and increasing an overload withstanding amount in a temporary overload state during commercial power supply.

[0002]

2. Description of the Related Art FIGS. 4 and 5 are block diagrams for explaining a control method of an uninterruptible power supply according to the prior art. FIG.
In, the uninterruptible power supply device 1 receives power from the commercial power source 21 to supply / interrupt commercial power, and to the semiconductor switch 3 having the semiconductor switch protection means 34, and to operate as a rectifier when the commercial power is healthy, to the battery 22. Of the power supply from the battery 22 at the time of power failure, the multi-function inverter 5 serving as an inverter, the bypass contactor 4 connected in parallel to the semiconductor switch 3, and the power failure detection means 32.
And are configured.

In such a configuration, in the conventional technique, the uninterruptible power supply 1 always receives power from the commercial power supply 21 and supplies power to the load 23 via the semiconductor switch 3. When a failure occurs in a part of the semiconductor switch 3, the uninterruptible power supply device 1 sets the multi-function inverter 5 to operate in the inverter mode and switches the power supply to the load 23 to the inverter power supply. After that, when the battery 22 runs out of power, the multi-function inverter 5 stops operating.

Further, FIG. 5 shows a block diagram used in the prior art in order to suppress the inrush current from the commercial power supply when the uninterruptible power supply 1 described in FIG. 4 is started. In order to suppress the inrush current, points different from those in FIG. 4 will be mainly described. Figure 5
In the uninterruptible power supply device 1, the start switch 25 for starting the device 1, the first contactor 51 connected between the multifunctional inverter 5 and the load 23, the battery 22 and the multifunctional inverter 5 are connected. A second contactor 52 connected to the first contactor 52, a capacitor 53 connected to the connection point between the second contactor 52 and the multi-function inverter 5, a third contactor 54 connected in parallel to the first contactor 51, and a resistor 55 in series. And a circuit.

In such a configuration, when the uninterruptible power supply is started by the conventional technique, the start switch 25
The third contactor 54 is closed, the first contactor 51 and the second contactor 52 are opened, the multifunctional inverter 5 is operated as a rectifier, and the initial charging current from the series circuit of the third contactor 54 and the resistor 55 to the capacitor 53 is increased. Is limited by the resistance 55 and the initial charge is performed for a few seconds. Next, the charging voltage of the capacity 53 is charged to a predetermined voltage, for example, a value close to the voltage of the battery 22, and the first contactor 51 and the second contactor are charged.
52 is closed.

Further, in the case of a load which is supplied with power from the commercial power source 21 and which is in an overload state in which a rush current such as a motor load temporarily flows, the semiconductor switch 3 is used in the conventional technique.
It had a large element to provide overload resistance.
Further, when the overload is further exceeded, the protective fuse is blown, or the temperature of the semiconductor switch becomes abnormal, and the power supply to the load 23 is stopped.

[0007]

In the above-mentioned prior art,
An uninterruptible power supply that constantly supplies power from a commercial power supply to a load is equipped with a multi-function inverter that functions as an inverter that receives power supply from a battery in the event of a power outage, etc. It is possible to supply power to the load from the multi-function inverter, but for a long time, the failure of the semiconductor switch will stop the power supply to the load. Therefore, consider it as the reliability of the semiconductor switch = the reliability of the device. You can

An object of the present invention is to (1) to enable an uninterruptible power supply that constantly supplies power from a commercial power supply to a load to continuously supply power to the load without interruption, thereby improving reliability. is there. (2) In addition, the initial charging circuit provided in the prior art is not required, and (3) In addition, in the case of a temporary overload state, power is supplied to the load without giving the semiconductor switch an excessive overload capacity. It is to prevent the stoppage, to ensure the reliability of the power supply to the load, and to reduce the cost.

The present invention has been made in view of the above points, and an object thereof is to solve the above-mentioned problems, to constantly supply power from a commercial power source, and to obtain a backup of a multifunctional inverter when the commercial power source is abnormal. The power supply system is switched from the commercial power supply to the backup battery without any interruption, the commercial power supply from the bypass contactor is received without interruption when the semiconductor switch fails, and the load is restored for a temporary overload condition. Another object of the present invention is to provide a control method of an uninterruptible power supply device that prevents the power supply to the power supply from being stopped, secures the reliability of the power supply to the load, and reduces the cost.

[0010]

In order to achieve the above object, in the first aspect of the present invention, a semiconductor switch that receives power from a commercial power source and supplies / shuts off commercial power, and a rectifier when commercial power is sound are provided. It is equipped with a multi-function inverter that charges the battery and receives power from the battery in the event of a power failure, and acts as an inverter. Power is supplied to the load from a commercial power source via a semiconductor switch at all times, and from the multi-function inverter to the load during a power failure. A control method for an uninterruptible power supply device that supplies power includes semiconductor switch failure detection means, a bypass contactor connected in parallel to the semiconductor switch, and a switching control circuit.

According to the second aspect of the invention, a semiconductor switch that receives power from a commercial power source and supplies / interrupts commercial power, and a battery is charged as a rectifier when the commercial power is healthy, and power is supplied from the battery when a power failure occurs. In the control method of the uninterruptible power supply device, which comprises a multifunctional inverter that operates as a receiving inverter, the load is constantly fed from a commercial power source through a semiconductor switch, and the power is fed from the multifunctional inverter during a power failure. A start switch that starts the power failure power supply, a phase angle control circuit that controls the phase angle of the semiconductor switch, a first contactor that is operated by the start switch and that is connected between the multi-function inverter and the load, and a battery A second contactor connected between the functional inverter and a capacitor connected to the connection point between the second contactor and the multifunctional inverter; It shall be equipped with a.

According to the third aspect of the invention, a semiconductor switch that receives power from a commercial power source to supply / shut off commercial power, and a battery is charged as a rectifier when the commercial power is healthy, and power is supplied from the battery when a power failure occurs. A control method for an uninterruptible power supply device, comprising: a multi-function inverter that functions as a receiving inverter; and a power supply that constantly supplies power to a load from a commercial power supply through a semiconductor switch, and a multi-function inverter that supplies power to the load during a power failure. The switch is provided with an overcurrent detecting means and a bypass contactor connected in parallel with the semiconductor switch.

[0013]

With the above structure, in the first invention, when a failure occurs in the semiconductor switch when the power is supplied from the commercial power source, the semiconductor switch failure detecting means detects the failure of the semiconductor switch, and the switching control circuit is provided by the switching control circuit. The power supply is switched from multi-function inverter to power supply without interruption by a switch failure signal, the presence or absence of commercial power is determined, a bypass contactor is turned on, and power is restored from the commercial power supply via the bypass contactor.

In the second invention, when the uninterruptible power supply is started by the start switch, the start switch closes the first contactor and opens the second contactor to operate the multifunctional inverter as a rectifier. The angle control circuit detects the voltage waveform on the input side of the semiconductor switch, controls the phase angle of the semiconductor switch, gradually outputs the voltage when the uninterruptible power supply is started, and initially charges the capacitor.

Further, in the third aspect of the invention, when an overload occurs when power is supplied from the commercial power source, the overcurrent detecting means detects the overload state and turns on the bypass contactor. Also,
When returning from the overload state after the overload occurs when the power is supplied from the commercial power supply and the bypass contactor is turned on to switch to the power supply state from the commercial power supply, the overcurrent detection means causes the load current to fall below the predetermined reset current value. The bypass contactor is shut off by continuing the above state for a certain period of time.

[0016]

1 is a block diagram for explaining a control method of an uninterruptible power supply according to an embodiment corresponding to the first invention of the present invention, and FIG. 2 shows another embodiment corresponding to the second invention. FIG. 3 is a block diagram, and FIG. 3 is a block diagram of another embodiment corresponding to the third invention, and the same functional members corresponding to FIGS. 4 and 5 are designated by the same reference numerals.

Embodiment 1 FIG. 1 shows that when the semiconductor switch 3 fails, the load
FIG. 11 is a block diagram illustrating a control method of an uninterruptible power supply device capable of continuing power supply to 23. In FIG. 1, an uninterruptible power supply 1 includes a semiconductor switch 3 that receives power from a commercial power supply 21 to supply / shut off commercial power, and operates as a rectifier when the commercial power is healthy to charge a battery 22. During a power failure, the multifunctional inverter 5 receives power from the battery 22 and acts as an inverter, semiconductor switch failure detection means 31, power failure detection means 32, bypass contactor 4 connected in parallel to the semiconductor switch 3, and switching control circuit 6 And are configured.

In such a configuration, the uninterruptible power supply 1
Constantly supplies power from the commercial power source 21 to the load 23 via the semiconductor switch 3, and at the same time, the multifunctional inverter 5 operates as a converter, and the commercial power source 21 drives the battery 22.
Charge to. At the time of a power failure, the power failure detection signal 62 from the power failure detection means 32 controls the switching control circuit 6 that switches the operation mode of the multifunctional inverter 5, and the control signal 64 of this control circuit 6 causes the multifunctional inverter 5 to operate in the converter mode. To the inverter mode, and power is supplied from the multi-function inverter 5 to the load 23.

When a failure occurs in the semiconductor switch 3 when power is supplied from the commercial power source 21 to the load 23, the semiconductor switch failure detection means 31 detects the failure of the semiconductor switch 3,
The fault signal 61 is output. The switching control circuit 6 takes the logical sum of the power failure detection signal 62 and the failure signal 61 and outputs the control signal 64 to switch the multi-function inverter 5 from the converter mode to the inverter mode for commercial operation without interruption. The power from the power supply 21 supplies the power from the battery 22 by the multi-function inverter 5 to the load 23. After that, when the battery 22 approaches the discharge end voltage 63, the switching control circuit 6
Judges whether or not there is a commercial voltage of the commercial power source 21, and if this voltage is present, outputs a control signal 65, turns on the bypass contactor 4, and turns on the inverter voltage from the multifunctional inverter 5 and the bypass contactor 4. After overlapping the voltage from the commercial power supply 21 via the control signal 64, the multi-function inverter 5 is stopped and the power supply from the commercial power supply 21 via the bypass contactor 4 is restored. The method for returning to the power supply from the commercial power source 21 via the bypass contactor 4 is provided with a timer inside the switching control circuit 6, and after the timer has passed a certain time, the control signal 65 is output, and as described above. There is also a method of switching without interruption.

The semiconductor switch failure detection means 31 is, for example, a contact signal between a fuse F with an alarm contact which operates at high speed in series with the semiconductor switch 3 due to an overcurrent, and a temperature sensor output provided on a cooling fin of the semiconductor switch 3. The failure of the semiconductor switch 3 in the short-circuit mode (including overload current) is detected from the logical OR of the two, and the power failure detection means 32 monitors the voltage on the output side of the semiconductor switch 3 to detect the open mode of the semiconductor switch 3. It is possible to detect the failure of the fuse F and the blowout of the fuse F.

With this configuration, the uninterruptible power supply 1 is
By obtaining the overload capacity of the semiconductor switch 3 from the short-time overload characteristics expected for the load 23 and selecting a suitable semiconductor switch 3, the reliability of the semiconductor switch 3 itself is ensured and the reliability of the power supply to the load is assured. It is possible to secure the property and reduce the cost. Second Embodiment FIG. 2 is a block diagram of another embodiment corresponding to the second aspect of the invention, which is a commercial power supply 21 for starting the uninterruptible power supply 1.
The inrush current generated on the side is suppressed. In FIG. 2, an uninterruptible power supply 1 is a semiconductor switch 3 that receives power from a commercial power supply 21 and supplies / shuts off commercial power.
A multi-function inverter 5 that charges the battery 22 as a rectifier when the commercial power is healthy, and receives power from the battery 22 when a power failure occurs, and acts as an inverter; a start switch 25 that starts the uninterruptible power supply 1; and a semiconductor switch 3 Between the battery 22 and the multi-function inverter 5, the first contactor 51 that is operated by the start switch 25 and that is connected between the multi-function inverter 5 and the load 23. A second contactor 52 connected to
The contactor 52 and the capacitor 53 connected to the connection point of the multifunctional inverter 5 are provided.

In this structure, as in the first embodiment,
The uninterruptible power supply 1 always supplies power from the commercial power supply 21 to the load 23 via the semiconductor switch 3, and at the same time, the multifunctional inverter 5 operates in the converter mode to charge the commercial power supply 21 to the battery 22. To do. At the time of power failure, a power failure detection signal 61 from a power failure detection means 32 (not shown) switches the operation mode of the multi-function inverter 5 from the converter mode to the inverter mode, and supplies power from the multi-function inverter 5 to the load 23. .

When the uninterruptible power supply 1 is started, first, the start switch 25 is pushed to start the first contactor 51.
Is immediately closed / closed, the second contactor 52 is left open, and the multifunctional inverter 5 is operated as a rectifier.
After confirming the answer back that the first contactor 51 has operated, the phase angle control circuit 33 controls the phase angle of the semiconductor switch 3 and gradually increases the output voltage from zero output. This output voltage is diode rectified by the control element module of the multi-function inverter unit to initially charge the capacitor 53. When this initial charging is completed, the multifunctional inverter 5
Performs a boosting operation to boost the DC voltage to a value slightly higher than the voltage of the battery 22. After that, the second contactor 52
Turn on and close.

Embodiment 3 FIG. 3 is a block diagram of another embodiment corresponding to the third invention, in which an inrush current of a motor load or the like temporarily flows and a temporary overload state occurs. Thus, the power supply to the load is prevented from being stopped without providing the semiconductor switch with an excessive overload resistance, the reliability of the power supply to the load is ensured, and the cost is reduced.

In FIG. 3, the uninterruptible power supply unit 1 is supplied with power from a commercial power source 21, and is provided with a semiconductor switch 3 for supplying / shutting off commercial power, a rectifier when the commercial power is healthy, and a battery 22 when a power failure occurs. The multi-function inverter 5 which receives power supply and acts as an inverter, the overcurrent detection means 35, and the bypass contactor 4 connected in parallel to the semiconductor switch 3 are provided, and the overcurrent detection means 35 is the one shown in FIG. In the embodiment, the overcurrent detector 36 and this overcurrent detector 36
The comparator 37 that compares the overcurrent value detected in step 3 and gives an operation command to the bypass contactor 4 and the comparator 37 that compares the overcurrent value and gives a return command to the bypass contactor 4
38 and a confirmation time limit timer 39.

In such a configuration, the main operation of the uninterruptible power supply device 1 is the same as that described in the first and second embodiments, so here, the semiconductor switch protection system against a temporary overload condition of the load is used. I will explain mainly. A temporary overload state is a temporary overload state when, for example, a motor is used as a load and the motor is started or accelerated, or when a plurality of electronic devices are connected as a load and the electronic device is powered on. Inrush current flows as load current.

If the load current of the load 23 increases while supplying power from the commercial power source 21 to the load 23 and exceeds the rated current, the overcurrent detector 36 detects the overcurrent value and the comparator 37 detects the overcurrent. In comparison with the setting, when the detected overcurrent value is larger than this overcurrent set value, the closing contactor 4 is turned on, the bypass contactor 4 is turned on, and the overload current is shunted via this bypass contactor 4. . next,
When the temporary overload condition subsides and the load current gradually decreases, the comparator 38 compares the detected overcurrent value with the reset set value, and the detected overcurrent value is smaller than this reset set value. Confirm that timed timer 39
By confirming in step 1, the bypass contactor 4 that was operated previously is shut off.

Until the load enters a temporary overload state and the bypass contactor 4 is turned on, the semiconductor switch 3
Goes into overload. The overload withstanding capacity of the semiconductor switch 3 at this time is selected from the assumed overload current value and its time period characteristic, and the maximum time period is the time until the overcurrent is detected and the bypass contactor 4 operates. In the conventional technique, an element having a large capacitance is selected for the overload withstanding capacity of the semiconductor switch 3, and when the overload current is larger than the overload withstanding capacity of the selected element, the protective fuse is blown out or the temperature of the semiconductor switch 3 is abnormal. Although the power supply was stopped at this time, by operating the bypass contactor 4, the power to the load is exceeded by a temporary overload condition which is longer than the overload withstanding capacity of the semiconductor switch element, which is rated for a relatively short time. The supply can be effectively maintained.

[0029]

As described above, according to the present invention, (1) the reliability of the uninterruptible power supply, which constantly supplies power from the commercial power supply, as a measure of the time until the power supplied to the load is momentarily interrupted ( In the prior art, availability was determined only by (reliability of semiconductor switch),
(Reliability of semiconductor switch + battery compensation time + time until next power failure occurs). (2) By controlling the phase angle of the semiconductor switch when the power is turned on, the resistor and contactor circuits required for initial charging in the prior art can be dispensed with. (3) In addition, by detecting a temporary overload current and shunting this overload current to the bypass contactor, it is possible to prevent the power supply to the load from being stopped without giving the semiconductor switch an excessive overload capacity. It is possible to prevent this, to secure the reliability of the power supply to the load, and to reduce the cost.

[Brief description of drawings]

FIG. 1 is a block diagram illustrating a control method of an uninterruptible power supply according to an embodiment corresponding to a first invention.

FIG. 2 is a block diagram of another embodiment corresponding to the second invention.

FIG. 3 is a block diagram of another embodiment corresponding to the third invention.

FIG. 4 is a block diagram illustrating an example of a conventional uninterruptible power supply device.

FIG. 5 is a block diagram illustrating another example of a conventional uninterruptible power supply.

[Explanation of symbols]

 1 Uninterruptible power supply 21 Commercial power supply 22 Battery 23 Load 3 Semiconductor switch 31 Semiconductor switch failure detection means 32 Power failure detection means 33 Phase angle control circuit 35 Overcurrent detection means 36 Overcurrent detector 37, 38 Comparator 39 Confirmation timed timer 4 Bypass Contactor 5 Multi-function inverter 51, 52, 54 Contactor 53 Capacity 55 Resistance 6 Switching control circuit 61 Failure signal 62 Power failure detection signal 63 Discharge end voltage 64, 65 Control signal

Claims (4)

[Claims] 1. A multi-functional semiconductor switch that receives power from a commercial power source and supplies / interrupts commercial power, and charges a battery as a rectifier when the commercial power is healthy and receives power from the battery when a power failure occurs and functions as an inverter. An inverter,
In the control method of the uninterruptible power supply, which constantly supplies power to the load from the commercial power supply through the semiconductor switch, and supplies power to the load from the multifunctional inverter during a power failure, semiconductor switch failure detection means, A bypass contactor connected in parallel to the semiconductor switch and a switching control circuit are provided, and when a failure occurs in the semiconductor switch when power is supplied from a commercial power source, the semiconductor switch failure detection unit detects the failure of the semiconductor switch. The switching control circuit detects the failure signal and switches to the power supply from the battery by the multi-function inverter without interruption, and further turns on the bypass contactor to supply power from the commercial power source via the bypass contactor. A method for controlling an uninterruptible power supply, which is characterized in that the power is restored. 2. A multi-function device that receives power from a commercial power source and supplies / interrupts commercial power, and charges a battery as a rectifier when the commercial power is healthy and receives power from the battery when a power failure occurs and functions as an inverter. An inverter,
In the control method of the uninterruptible power supply, which constantly supplies power to the load from the commercial power supply through the semiconductor switch, and supplies power to the load from the multi-function inverter during power failure, the uninterruptible power supply is activated. A start switch, a phase angle control circuit for controlling a phase angle of a semiconductor switch, a first contactor which is operated by the start switch and is connected between the multi-function inverter and a load, the battery and the multi-function inverter. A second contactor connected between the second contactor and a capacity connected to a connection point between the second contactor and the multi-function inverter; and when the uninterruptible power supply is started by the starting switch, the starting switch The first contactor is closed, the second contactor is opened, and the multifunctional inverter is operated as a rectifier, Performs phase angle control of the semiconductor switch by the serial control circuit, carries out an initial charge on the capacitor, a control method for an uninterruptible power supply, characterized in that. 3. A multi-functional semiconductor switch which receives power from a commercial power source and supplies / interrupts commercial power and charges a battery as a rectifier when the commercial power is healthy, and receives power from the battery when a power failure occurs and functions as an inverter. An inverter,
In the control method of the uninterruptible power supply device, which constantly supplies power to the load from the commercial power supply through the semiconductor switch, and supplies power to the load from the multi-function inverter during a power failure, wherein the semiconductor switch is an overcurrent. A bypass contactor connected in parallel with the semiconductor switch; and when an overload occurs when power is supplied from a commercial power source, the overcurrent detection means detects an overload state, and the bypass contactor The method for controlling an uninterruptible power supply is characterized in that: 4. The control method for an uninterruptible power supply according to claim 3, wherein an overload occurs when power is supplied from a commercial power source, a bypass contactor is turned on, and a power supply state from the commercial power source is entered, and then the overload state is restored. At this time, the overcurrent detecting means shuts off the bypass contactor by keeping the load current equal to or less than a predetermined return current value for a certain period of time, thereby interrupting the bypass contactor.