JPH0564378A - Uninterruptible power supply device - Google Patents

Abstract

PURPOSE:To prevent the deterioration or destruction of constituent components of a d.c. circuit even for the regenerative load by causing regenerative power generated by the regenerative load to be consumed by a resistor, with a switch turned into the ON state, when an inflow current or d.c. bus voltage to a storage battery comes to a specified value or above. CONSTITUTION:An inflow current to a storage battery 4 is detected by a current detector 7 and the increase in d.c. bus voltage is detected by a voltage detector 8. Then, the detected values are sent to a switching commander 9. The switching commander 9 sends a ON command to a switch 10 when the current value detected by the current detector 7 or the voltage value detected by the voltage detector 8 exceeds a value which is preliminarily set for each. After receiving the ON command from the switching commander 9, the switch 10 gets ON and leads regenerative power from the regeneration load 5 to a resistor 11 for the power to be consumed there. By this method, the regenerative power is prevented from flowing into the storage battery after the switch is turned ON.

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, and more particularly to an uninterruptible power supply device applied to a regenerative load such as an electric motor which generates regenerative power to the power supply side.

[0002]

2. Description of the Related Art FIG. 6 is a circuit diagram showing an example of a conventional uninterruptible power supply, particularly an uninterruptible power supply for regenerative load. In the figure, reference numeral 1 is an uninterruptible power supply, which is connected to an output side of the rectifier 2 which converts an alternating current input from a power source (not shown) into a direct current and outputs the direct current, and uses the direct current output as an input. Inverter 3 that converts this into AC again
And a storage battery 4 connected to a DC bus between the rectifier 2 and the inverter 3. Reference numeral 5 is a regenerative load connected to the output side of the inverter 3 and supplied with AC power from the uninterruptible power supply 1, for example, a regenerative load having a regenerative mode such as an electric motor.

The conventional uninterruptible power supply system 1 is constructed as described above, and the rectifier 2 converts this AC input power into DC power when the AC input is normal, charges the storage battery 4 and sends it to the inverter 3. Supply DC power. The inverter 3 reversely converts this DC power into AC power and supplies the AC power to the regenerative load 5. However, when the AC input to the rectifier becomes abnormal due to a power failure or the like, the inverter 3 receives the DC power from the storage battery 4 and continues to supply the AC power to the regenerative load 5. In this way, even if the AC input is cut off, the power supply to the regenerative load 5 is maintained.

The above is the operation when the regenerative load 5 such as an electric motor having the regenerative mode receives the supply of electric power (in the case of the electric motor, the running mode). However, when the regenerative load 5 regenerates the electric power, The flow goes from the regenerative load 5 to the uninterruptible power supply 1, and in the uninterruptible power supply 1, the rectifier 2 generally has only the function of converting AC power into DC power, and the reverse direction, that is, DC power is converted back into AC power. Since it does not have a function to operate, the regenerative power generated from the regenerative load 5 flows into the storage battery 4 through the inverter 3.

FIG. 7 is a circuit diagram showing another configuration example of a conventional uninterruptible power supply. The uninterruptible power supply 1A of FIG.
The only difference from the uninterruptible power supply device 1 is that the storage battery 4 is not directly connected to the DC bus between the rectifier 2 and the inverter 3, but is connected via a switch, for example, a DC switch 6, and 4 is controlled by a charger (not shown).

In the uninterruptible power supply system 1A constructed as shown in FIG. 7, the rectifier 2 converts this AC input power into DC power when the AC input is normal, and the DC switch 6 opens as shown. Therefore, the DC power is supplied only to the inverter 3. The inverter 3 reversely converts this DC power into AC power and supplies the AC power to the regenerative load 5.

However, when the AC input to the rectifier 2 becomes abnormal due to a power failure or the like, the inverter 3 receives the DC power from the storage battery 4 via the closed DC switch 6, and supplies the AC power to the regenerative load 5. Continue to supply. When the regenerative load 5 regenerates electric power, the flow of electric power is from the regenerative load 5 to the uninterruptible power supply 1A, and the DC circuit voltage is increased in the uninterruptible power supply 1A. Further, when regeneration occurs during storage battery operation, the storage battery 4 is overcharged.

[0008]

In the conventional uninterruptible power supply, when the regenerative load 5 is in the regenerative mode, electric power flows into the storage battery to raise the temperature of the storage battery or deteriorate the storage battery (shorten the life). Alternatively, by increasing the terminal voltage of the storage battery and thus the DC bus voltage of the uninterruptible power supply, the storage battery may be overcharged or the DC bus voltage may be increased to prevent deterioration or damage to the semiconductor components that compose the rectifier or inverter. There was a problem such as causing it.

The present invention has been made to solve the above problems, and an object thereof is to obtain an uninterruptible power supply which does not deteriorate or damage the components of the DC circuit even against a regenerative load. I am trying.

[0010]

An uninterruptible power supply system according to a first aspect of the present invention includes a rectifier for converting AC into DC, an inverter connected to an output side of the rectifier for converting the DC into AC again. In an uninterruptible power supply device that includes a rectifier and a storage battery connected to a DC bus between the inverter, and supplies AC power to a load that is connected to the output side of the inverter and generates regenerative power, and flows into the storage battery. A means for detecting a current, a means for detecting the voltage of the DC bus, a series circuit composed of a switch and a resistor connected to the DC bus, and the inflow current or the DC bus voltage has become a predetermined value or more. At this time, means for turning on the switch is provided, and the regenerative electric power generated by the regenerative load is consumed by the resistor.

The uninterruptible power supply according to the second invention is
The series circuit is connected to the AC output side of the inverter, not to the DC bus.

The uninterruptible power supply according to the third invention is
A rectifier that converts alternating current to direct current, an inverter that is connected to the output side of the rectifier and that converts the direct current to alternating current again, and a storage battery that is connected to the direct current bus bar between the rectifier and the inverter via a direct current switch. In the uninterruptible power supply device for supplying AC power to a load generating regenerative power, which is connected to the output side of the inverter, means for detecting the voltage of the DC bus, a switch connected to the DC bus, and When the DC bus bar voltage exceeds a specified value and a series circuit consisting of resistors, turn on the switch.
And means for bringing the regenerative power generated by the regenerative load into the resistor.

The uninterruptible power supply according to the fourth invention is
The series circuit is connected to the AC output side of the inverter, not to the DC bus.

The uninterruptible power supply according to the fifth invention is
A rectifier that converts alternating current to direct current and an inverter that is connected to the output side of the rectifier and that converts the direct current to alternating current again are provided, and the alternating current power is supplied to the load that is connected to the output side of the inverter and generates regenerative power. In the uninterruptible power supply to be supplied, the inverter is operated in synchronization with another AC power supply, the voltage detection means for detecting the voltage of the DC bus between the rectifier and the inverter, and the voltage of the DC bus exceeds a predetermined value. In this case, the control means is provided so that the inverter is once made asynchronous and the output frequency is not changed.

The uninterruptible power supply according to the sixth invention is
A rectifier that converts alternating current to direct current and an inverter that is connected to the output side of the rectifier and that converts the direct current to alternating current again are provided, and the alternating current power is supplied to the load that is connected to the output side of the inverter and generates regenerative power. In the uninterruptible power supply to be supplied, the inverter operates in synchronization with another AC power supply, and frequency detection means for detecting the bypass frequency of another power supply that operates in synchronization with the inverter, and the detected bypass frequency has dropped by a predetermined value or more. In this case, the inverter is once made asynchronous so that the output frequency is not changed.

The uninterruptible power supply according to the seventh invention is
A DC bus is provided with a storage battery, and a current detection means for detecting a current flowing into the storage battery is provided, and the control means does not change the output frequency of the inverter when the charging current of the storage battery becomes a predetermined value or more. It is a feature.

The uninterruptible power supply unit according to the eighth invention is
A rectifier that converts alternating current to direct current and an inverter that is connected to the output side of the rectifier and that converts the direct current to alternating current again are provided, and the alternating current power is supplied to the load that is connected to the output side of the inverter and generates regenerative power. In the uninterruptible power supply to be supplied, the inverter is operated in synchronization with another AC power supply, the voltage detection means for detecting the voltage of the DC bus between the rectifier and the inverter, and the voltage of the DC bus exceeds a predetermined value. In this case, the inverter is once made asynchronous and the control means for lowering the frequency at a limited rate of change is provided.

The uninterruptible power supply according to the ninth invention is
A rectifier that converts alternating current to direct current and an inverter that is connected to the output side of the rectifier and that converts the direct current to alternating current again are provided, and the alternating current power is supplied to the load that is connected to the output side of the inverter and generates regenerative power. In the uninterruptible power supply to be supplied, the inverter operates in synchronization with another AC power supply, and frequency detection means for detecting the bypass frequency of another power supply that operates in synchronization with the inverter, and the detected bypass frequency has dropped by a predetermined value or more. In this case, a control means for temporarily making the inverter asynchronous and lowering the frequency at a limited change rate is provided.

An uninterruptible power supply device according to a tenth aspect of the present invention includes a storage battery on a DC bus and a current detection means for detecting a current flowing into the storage battery, and the control means controls the charging current of the storage battery. It is characterized in that the output frequency of the inverter is reduced at a limited rate of change when the output voltage exceeds a predetermined value.

An uninterruptible power supply device according to an eleventh aspect of the present invention comprises a rectifier for converting AC into DC and an inverter connected to the output side of the rectifier for converting the DC into AC again. In an uninterruptible power supply device that supplies AC power to a load that is connected to the output side and that generates regenerative power, a means for detecting the voltage on the DC bus between the rectifier and the inverter, and the detected voltage on the DC bus exceeds a specified value. In this case, a control means for increasing the output frequency of the inverter is provided.

The uninterruptible power supply system according to the twelfth aspect of the invention comprises a rectifier for converting AC into DC and an inverter connected to the output side of the rectifier for converting the DC into AC again. In an uninterruptible power supply device that supplies AC power to a load that is connected to the output side and that generates regenerative power, a means for detecting the voltage on the DC bus between the rectifier and the inverter, and the detected voltage on the DC bus exceeds a specified value. In this case, a control means for increasing the output frequency and the output voltage of the inverter is provided.

The uninterruptible power supply according to the thirteenth aspect of the present invention comprises a rectifier for converting AC into DC and an inverter connected to the output side of the rectifier for converting the DC into AC again. In an uninterruptible power supply device that supplies AC power to a load that is connected to the output side and that generates regenerative power, the inverter operates in synchronization with another AC power supply, and the bypass frequency of another power supply that operates in synchronization with the inverter is set. It is characterized by comprising frequency detecting means for detecting and control means for increasing the output frequency of the inverter when the frequency of the other power source decreases by a predetermined value or more.

The uninterruptible power supply according to the fourteenth aspect of the invention comprises a rectifier for converting AC into DC and an inverter connected to the output side of the rectifier for converting the DC into AC again. In an uninterruptible power supply device that supplies AC power to a load that is connected to the output side and that generates regenerative power, the inverter operates in synchronization with another AC power supply, and the bypass frequency of another power supply that operates in synchronization with the inverter is set. A frequency detecting means for detecting and a control means for increasing the output frequency and the output voltage of the inverter when the frequency of the other power source decreases by a predetermined value or more.

The uninterruptible power supply according to the fifteenth aspect of the invention includes a storage battery on the DC bus between the rectifier and the inverter, and detection means for detecting the charging current of the storage battery, and the control means is the detection means. It is characterized in that the output frequency of the inverter is increased when the charging current due to is above a predetermined value.

[0025]

In the uninterruptible power supply device of the first invention, when the inflow current to the storage battery or the DC bus voltage becomes a predetermined value or more, the switch is turned on and the regenerative power generated by the regenerative load is transferred to the resistor. To consume.

In the uninterruptible power supply of the second invention, the resistor according to the first invention is provided on the AC output side of the inverter,
When the current flowing into the storage battery or the DC bus voltage exceeds a predetermined value, the resistor consumes regenerative power.

In the uninterruptible power supply device of the third invention, when the DC bus voltage exceeds a predetermined value, the switch is turned on and the regenerative power generated by the regenerative load is consumed by the resistor.

In the uninterruptible power supply of the fourth invention, the resistor according to the third invention is provided on the AC output side of the inverter,
When the DC bus voltage exceeds a predetermined value, the resistor causes the regenerative power to be consumed.

In the uninterruptible power supply of the fifth invention, the inverter is operated in synchronization with another AC power supply, and when the voltage of the DC busbar between the rectifier and the inverter becomes equal to or higher than a predetermined value, the control means described above. Make the inverter asynchronous so that the output frequency does not change.

In the uninterruptible power supply of the sixth aspect of the invention, when the detection bypass frequency by the frequency detecting means is lowered by a predetermined value or more, the control means makes the inverter once asynchronous with another AC power supply so as not to change the output frequency. To do.

In the uninterruptible power supply device of the seventh invention, in contrast to the fifth and sixth inventions, the current flowing into the storage battery provided on the DC bus is detected by the current detecting means, and the charging current of the storage battery becomes a predetermined value or more. When it becomes, control means will not change the output frequency of the inverter.

In the uninterruptible power supply of the eighth aspect of the invention, the voltage of the DC busbar by the voltage detecting means for operating the inverter in synchronization with another AC power supply and detecting the voltage of the DC busbar between the rectifier and the inverter is a predetermined value. In the case of the above, the inverter is once made asynchronous by the control means and the frequency is lowered at the limited rate of change.

In the uninterruptible power supply according to the ninth aspect of the invention, the bypass frequency detected by the frequency detecting means for operating the inverter in synchronization with another AC power source and detecting the bypass frequency of another power source operating in synchronization with the inverter is predetermined. When the voltage drops by more than the value, the control means once makes the inverter asynchronous so as to lower the frequency at a limited rate of change.

In the uninterruptible power supply of the tenth invention,
When the charging current of the storage battery by the current detecting means for detecting the current flowing into the storage battery provided on the DC bus exceeds a predetermined value, the control means reduces the output frequency of the inverter at a limited rate of change.

In the uninterruptible power supply system of the eleventh invention,
When the voltage detected by the voltage detecting means for detecting the voltage of the DC bus between the rectifier and the inverter exceeds a predetermined value, the control means increases the output frequency of the inverter.

In the uninterruptible power supply system of the twelfth invention,
When the voltage detected by the voltage detecting means for detecting the voltage of the DC bus between the rectifier and the inverter becomes a predetermined value or more, the control means increases the output frequency and the output voltage of the inverter.

In the uninterruptible power supply system of the thirteenth invention,
When the frequency of the other power supply detected by the frequency detection means for detecting the bypass frequency of the other power supply that operates in synchronization with the inverter decreases by a predetermined value or more, the control means increases the output frequency of the inverter.

In the uninterruptible power supply of the fourteenth invention,
When the frequency of the other power source detected by the frequency detection unit that detects the bypass frequency of the other power source that operates in synchronization with the inverter decreases by a predetermined value or more, the control unit increases the output frequency and the output voltage of the inverter.

In the uninterruptible power supply of the fifteenth invention,
In the eleventh to fourteenth inventions, when the charging current by the current detecting means for detecting the charging current of the storage battery provided on the DC bus between the rectifier and the inverter becomes a predetermined value or more,
The output frequency of the inverter is increased by the control means.

[0040]

EXAMPLES Example 1. Hereinafter, the present invention will be described for each example. FIG. 1 is a circuit diagram showing an embodiment of the uninterruptible power supply device 1B according to the first aspect of the present invention. In the figure, 2 to 5 are the same as those described with reference to FIG. 7 is a current detector connected to the DC bus to detect the current flowing into the storage battery 4, 8 is a voltage detector connected to the DC bus to detect the terminal voltage of the storage battery, that is, the DC bus voltage of the uninterruptible power supply 1B, Reference numeral 9 is an open / close commander that receives a detection value from the current detector 7 or the voltage detector 7 to judge ON / OFF of the switch in the next stage, 10 is a switch connected to the DC bus, and 11 is this switch 10. It is a resistor connected in series.

In the uninterruptible power supply unit 1B having the above structure,
When the regenerative load 5 such as an electric motor generates regenerative power, this regenerative power flows backward through the inverter 3 and the uninterruptible power supply 1B.
Of the DC bus, that is, the bus between the rectifier 2 and the inverter 3. At this time, since the rectifier 2 described above has only a one-way function of converting AC power into DC power, and does not have a function of reverse conversion of DC into AC, regenerative power flowing into the DC bus passes through the rectifier 2 to the AC power supply. It cannot flow to the side and flows into the storage battery 4, and as a result, the terminal voltage of the storage battery 4, that is, the DC bus voltage is increased.

The current flowing into the storage battery 4 is detected by the current detector 7 and the rise of the DC bus voltage is detected by the voltage detector 8, and these signals are given to the switching commander 9. The opening / closing commander 9 gives an ON command to the switch 10 when the current value detected by the current detector 7 or the voltage value detected by the voltage detector 8 exceeds a preset value. The switch 10 is turned on according to the ON command of the opening / closing command device 9, guides the regenerative power from the regenerative load 5 to the resistor 11 and consumes it there, and prevents the regenerative power from flowing into the storage battery 4 after the switch 10 is turned on. To do.

Example 2. FIG. 2 relates to the second invention,
It is a circuit diagram which shows the modification 1C of the uninterruptible power supply 1B shown in FIG. 1, and the series circuit which consists of the switch 10 and the resistor 11 is connected to the DC bus of an uninterruptible power supply, ie, not between the rectifier 2 and the inverter 3. The output side of the inverter 3, that is, the AC output busbar of the uninterruptible power supply 1C between the inverter 3 and the regenerative load 5 is connected.

Also in this embodiment, by providing a series circuit including the switch 10 and the resistor 11 on the side of the AC output bus, the regenerative power from the regenerative load is guided to the resistor 11 based on the current and voltage detection of the DC bus. Let it be consumed here,
It is possible to prevent regenerative power from flowing into the storage battery 4 after the switch 10 is turned on.

Example 3. FIG. 3 is a circuit diagram showing another embodiment 1D of the uninterruptible power supply device according to the third invention, in which 2 to 6 are the same as those described with reference to FIG.
And 8, 10, 11 are the same as those described with reference to FIG. Reference numeral 9A is an opening / closing command device that receives a detection value from the voltage detector 8 and determines whether the switch 10 is ON or OFF.

Also in the uninterruptible power supply 1D shown in FIG. 3, when the regenerative load 5 such as an electric motor generates regenerative power, this regenerative power flows backward through the inverter 3 and the DC bus of the uninterruptible power supply 1D, that is, the rectifier and the inverter. It flows into the bus line between 3 and. At this time, the regenerative power flowing into the DC bus is rectified by the rectifier 2
Cannot flow to the side of the AC power supply through, and raises the DC bus voltage.

The voltage detector 8 detects the rise in the DC bus voltage, and the detected value is given to the switching commander 9A. The opening / closing command device 9A gives an ON command to the switch 10 when the voltage value detected by the voltage detector 8 exceeds a preset value. Switch 10 turns ON / OFF commander 9A
The power is turned on according to the command, the regenerative power from the regenerative load 5 is guided to the resistor 11 and consumed there, and the rise of the DC bus voltage due to the regenerative power after the switch 10 is turned on is prevented.

Example 4. FIG. 4 is a circuit diagram according to a fourth invention showing a modification 1E of the uninterruptible power supply 1D shown in FIG. 3 which is similar to FIG.

In the embodiment shown in FIG. 4 as well, the AC output bus bar is provided with a series circuit composed of the switch 10 and the resistor 11, so that the regenerative power from the regenerative load is guided to the resistor 11 based on the voltage detection of the DC bus bar. Let it be consumed here,
It is possible to prevent regenerative power from flowing into the storage battery 4 after the switch 10 is turned on.

Although the switch in the series circuit is shown as a mechanical switch in the above embodiment, it may be a semiconductor switch such as a transistor or a thyristor. Further, although the regenerative load is shown as an electric motor or the like in the above-described embodiments, the same effect can be obtained not only with a single electric motor configuration but also with a regenerative leonard device or an AC variable control device that is a DC motor control device.

When a series circuit composed of the switch 10 and the resistor 11 is provided in the AC circuit, a method of inserting a rectifier between the AC output side and the switch to operate the series circuit composed of the switch and the resistor in DC is also considered. Be done.

Although the contents of the invention have been described with respect to the uninterruptible power supply, the same effect can be expected in a frequency conversion circuit that supplies electric power of a constant voltage frequency to a load and has no storage battery equipment.

Example 5. FIG. 5 is a circuit diagram showing an uninterruptible power supply device 1F according to the fifth to fifteenth inventions. In the figure, 2 to 7 are the same as those described with reference to FIGS. 12 is a current detection comparator that compares the current detected by the current detector 7 that detects the current flowing into the storage battery 4 with a set value, and 13 detects the terminal voltage of the storage battery 4, that is, the voltage of the DC bus of the uninterruptible power supply. A voltage detection comparator for comparing the set value with a set value, 14 a frequency detection comparator for detecting a bus path frequency and comparing it with the set value, and a switching command device 15 for receiving a signal from the above comparator and giving a command to the frequency adjustment controller 16 Is a frequency adjustment controller that makes the output frequency of the inverter 3 asynchronous with the bypass frequency and switches it to the oscillator 17. By controlling the inverter frequency, the load rotation speed> the inverter output frequency, and the regenerative electric energy of the connected regenerative load is excessive. It works so as not to become.

Reference numerals 3a and 5a denote an inverter side changeover switch and a bypass side changeover switch. Normally, the inverter side changeover switch 3a is closed, and the bypass side changeover switch 5a.
Is an open state, and if the current of the load 5 exceeds the rating of the inverter 3 or the inverter 3 fails and the power cannot be supplied to the load 5, the inverter side changeover switch 3a Is opened, the bypass side changeover switch 5a is closed, and power is supplied to the load 5 from a bypass circuit (not shown). In order to perform this switching without interruption, the inverter 3 is always operated in synchronization with a bypass circuit, that is, another AC power source.

The uninterruptible power supply 1F shown in FIG.
In the regenerative mode of the regenerative load 5 of the uninterruptible power supply 1B, the switch 10 is turned on and the resistor 11 processes the regenerative power, but this is small in size because the device becomes large and expensive. When the current flowing into the storage battery 4 and the terminal voltage of the storage battery 4, that is, the DC bus voltage of the uninterruptible power supply 1F is detected or the bypass frequency decrease is detected, the inverter 3 is made inexpensive.
Is configured so as to fix the output frequency of or to limit the follow-up range to the bypass frequency, and by controlling the frequency of the inverter 3, it operates so that the regenerative electric energy of the connected regenerative load 5 does not become excessive. ..

Next, the operation will be described. When the regenerative load 5 such as an electric motor generates regenerative power, the regenerative power flows backward through the inverter 3 via the inverter side changeover switch 3a and flows into the DC bus of the uninterruptible power supply 1F. At this time, as described above, the rectifier 2 has only the forward conversion function of converting AC power into DC power, and does not have the function of reverse conversion of DC into AC, so that the regenerative power flowing into the DC bus is
The current does not flow to the AC power source side through the rectifier 2 but flows into the storage battery 4, and as a result, the terminal voltage of the storage battery 4, that is, the voltage of the DC bus is increased. When a current of a predetermined value or more flows into the storage battery 4, the current is detected by the current detector 7, and the signal passed through the current detection comparator 12 is input to the switching command device 15.

The switching commander 15 is configured such that the current value from the current detection comparator 8 or the voltage value detected by the voltage detection comparator 13 exceeds the set value, or the frequency value detected by the frequency detection comparator 14 is more than the set value. When the voltage drops, the inverter 3 is made asynchronous with another power source that is synchronously operated, and a switching command is given to the frequency adjustment controller 16. The frequency adjustment control device 16 switches to the oscillator 17 according to a command from the switching command device 15 to fix the inverter output frequency. As a result, the load rotation speed becomes less than the inverter output frequency, and the regenerative power is suppressed to prevent the regenerative power from flowing into the storage battery 4.

Example 6. In the above-described fifth embodiment, in the uninterruptible power supply 1F shown in FIG. 5, the frequency adjustment controller 1
At 6 the inverter output frequency was made asynchronous with the bypass frequency and switched to the oscillator 17, but without switching this, the frequency was lowered at a slew rate (rate of change) in the range in which the DC voltage did not rise, so that the load rotation speed <inverter output The regenerative power may be suppressed as a frequency to prevent the regenerative power from flowing into the storage battery 4, and the same effect as that of the above-described embodiment is obtained.

Example 7. Further, in the configuration shown in FIG. 5, the same effect as that of the above-described embodiment is obtained by operating as follows. That is, when the regenerative load 5 generates regenerative power, it cannot flow out to the AC power source side through the rectifier 2 and flows into the storage battery 4, resulting in an increase in the terminal voltage of the storage battery 4, that is, the DC bus voltage. When a current of a predetermined value or more flows into the storage battery 4, it is detected by the current detector 7 and the current detection comparator 12, and when the DC bus voltage rises to a predetermined value or more, it is detected by the voltage detector comparator 13, and these Signal commander 1
Enter in 5.

The frequency adjustment controller 16 raises the frequency of the inverter via the signal commander 15 by the signal of the current detection comparator 12 or the signal detected by the voltage detection comparator 13. As a result, the amount of regenerative electric power of the connected regenerative load 5 does not become excessive, and the inflow into the storage battery 4 can be prevented.

Example 8. In the above embodiment, the method of detecting the increase of the DC bus voltage and the increase of the inflow current to the storage battery has been described, but the decrease of the bypass input frequency is detected to prevent the regenerative power from flowing into the storage battery 4. be able to. That is, the frequency detection comparator 1 of FIG.
The decrease of the bypass input frequency is detected by 4, and this signal is input to the frequency adjustment controller 16 for controlling the voltage and frequency via the signal commander 15. When the frequency adjustment controller 16 raises the frequency of the inverter 3 or raises the voltage, the inverter load frequency> motor rotation speed causes the motor load 5 to run, thereby preventing regenerative power from flowing into the storage battery 4. ..

Further, the invention can be carried out according to the aspect of the constitution shown below. 1) Rectifier 2 for converting alternating current to direct current,
An uninterruptible power supply that is connected to the output side of the rectifier 2 and that converts the direct current into an alternating current again, and that supplies AC power to a load 5 that is connected to the output side of the inverter 3 and that generates regenerative power. In the device, the inverter 3 is operated in synchronization with another AC power source, and the voltage detection means 13 for detecting the voltage of the DC bus between the rectifier 2 and the inverter 3 and the voltage of the DC bus become a predetermined value or more. In this case, the uninterruptible power supply device is provided with a control means 16 which makes the inverter 3 asynchronous once and does not change the output frequency.

2) A rectifier 2 for converting AC into DC and an inverter 3 connected to the output side of the rectifier 2 for converting the DC into AC again are connected to the output side of the inverter 3 for regeneration. In the uninterruptible power supply that supplies AC power to the load 5 that generates power, the inverter 3
Operates in synchronization with another AC power supply and detects the bypass frequency of another power supply that operates in synchronization with the inverter 3, and the inverter is once made asynchronous when the detected bypass frequency drops by a predetermined value or more. An uninterruptible power supply comprising a control means 16 that does not change the output frequency.

3) The DC bus is provided with the storage battery 4, and
Current control means 7 and 12 for detecting the current flowing into the storage battery 4 are provided, and the control means 16 does not change the output frequency of the inverter 3 when the charging current of the storage battery 4 becomes a predetermined value or more. 1) or 2)
Uninterruptible power supply described.

4) A rectifier 2 for converting alternating current into direct current and an inverter 3 connected to the output side of the rectifier 2 for converting the direct current into alternating current again are provided and connected to the output side of the inverter 3 for regeneration. In the uninterruptible power supply that supplies AC power to the load 5 that generates power, the inverter 3
Is operated in synchronization with another AC power supply, and is a voltage detection means 1 for detecting the voltage of the DC bus between the rectifier 2 and the inverter 3.
3. An uninterruptible power supply device comprising: 3, and a control means for temporarily setting the inverter 3 to be asynchronous when the voltage of the DC bus exceeds a predetermined value and lowering the frequency at a limited rate of change.

5) A rectifier 2 for converting AC into DC and an inverter 3 connected to the output side of the rectifier 2 for converting the DC into AC again are provided. The rectifier 2 is connected to the output side of the inverter 3 for regeneration. In the uninterruptible power supply that supplies AC power to the load 5 that generates power, the inverter 3
Operates in synchronization with another AC power supply and detects the bypass frequency of another power supply that operates in synchronization with the inverter 3, and the inverter is once made asynchronous when the detected bypass frequency drops by a predetermined value or more. An uninterruptible power supply device comprising a control means 16 for reducing the frequency at a limited rate of change.

6) The DC bus is provided with the storage battery 4, and
The control means 16 includes current detection means 7 and 12 for detecting a current flowing into the storage battery 4, and the control means 16 limits the output frequency of the inverter 3 when the charging current of the storage battery 4 becomes a predetermined value or more. 4. The uninterruptible power supply device according to 4) or 5), characterized in that

7) A rectifier 2 for converting AC into DC and an inverter 3 connected to the output side of the rectifier 2 for converting the DC into AC again are provided. The rectifier 2 is connected to the output side of the inverter 3 for regeneration. In an uninterruptible power supply device that supplies AC power to a load 5 that generates power, means 13 for detecting the voltage of the DC bus between the rectifier 2 and the inverter 3, and the above when the detected voltage of the DC bus exceeds a predetermined value. An uninterruptible power supply comprising a control means 16 for increasing the output frequency of the inverter.

8) A rectifier 2 for converting AC into DC and an inverter 3 connected to the output side of the rectifier 2 for converting the DC into AC again are provided. The rectifier 2 is connected to the output side of the inverter 3 for regeneration. In an uninterruptible power supply device that supplies AC power to a load 5 that generates power, means 13 for detecting the voltage of the DC bus between the rectifier 2 and the inverter 3, and the above when the detected voltage of the DC bus exceeds a predetermined value. Control means 1 for increasing the output frequency and output voltage of the inverter 3
An uninterruptible power supply characterized by comprising 6.

9) A rectifier 2 for converting AC into DC and an inverter 3 connected to the output side of the rectifier 2 for converting the DC into AC again are provided. The rectifier 2 is connected to the output side of the inverter 3 for regeneration. In the uninterruptible power supply that supplies AC power to the load 5 that generates power, the inverter 3
Is operated in synchronization with another AC power supply and detects the bypass frequency of another power supply that operates in synchronization with the inverter 3, and the inverter 3 when the frequency of the other power supply drops by a predetermined value or more. An uninterruptible power supply comprising: a control means 16 for increasing the output frequency of the power supply.

10) Rectifier 2 for converting alternating current into direct current,
An uninterruptible power supply device that is connected to an output side of the rectifier 2 and that converts the direct current into an alternating current again, and that supplies alternating current power to a load that is connected to the output side of the inverter 3 and generates regenerative power. In the above inverter 3
Is operated in synchronization with another AC power supply and detects the bypass frequency of another power supply that operates in synchronization with the inverter 3, and the inverter 3 when the frequency of the other power supply drops by a predetermined value or more. An uninterruptible power supply comprising the control means 16 for increasing the output frequency and the output voltage of the above.

11) A storage battery 4 is provided on the DC bus between the rectifier 2 and the inverter 3, and detection means 7 for detecting the charging current of the storage battery 4 is provided.
The uninterruptible power supply device according to any one of 7) to 10), characterized in that the output frequency of the inverter is increased when the charging current by the detection means 7 becomes equal to or higher than a predetermined value.

[0073]

As described above, according to the first aspect of the present invention, the means for detecting the current flowing into the storage battery, the means for detecting the terminal voltage of the storage battery, that is, the voltage of the DC bus of the uninterruptible power supply, and the inverter. And a series circuit connected to the DC input side or AC output side of the switch and a resistor, and means for turning on the switch when the inflow current or the DC bus voltage exceeds a predetermined value. Since the regenerative power can be consumed by the series circuit, it is possible to prevent the regenerative power from flowing into the storage battery after the switch is turned on and to apply the uninterruptible power supply to the regenerative load which has been difficult to apply in the past. ..

According to the second invention, the series circuit is provided not on the DC bus but on the AC bus, that is, on the AC output side of the inverter. Therefore, the same effect as that of the first invention is obtained.

Further, according to the third invention, since the means for turning on the switch when the DC bus voltage becomes a predetermined value or more is provided, the same effect as the first invention can be obtained.

According to the fourth aspect of the invention, since the series circuit is provided not on the DC bus but on the AC bus, that is, on the AC output side of the inverter, the same effects as the third invention are obtained.

According to the fifth aspect of the invention, the inverter is operated in synchronization with another AC power source, and when the voltage of the DC bus exceeds a predetermined value, the inverter is once made asynchronous so that the output frequency is not changed. Since it is fixed to, the regeneration of the electric power from the circuit load is eliminated and the rise of the DC voltage can be prevented.

According to the sixth aspect of the invention, when the inverter is operated in synchronization with another AC power supply and the detected bypass frequency of the other AC power supply drops by a predetermined value or more, the inverter is once made asynchronous and the output frequency is changed. Is fixed so as not to change, it is possible to prevent the stable operation of the uninterruptible power supply from being hindered by the frequency fluctuation of the bypass power supply, in addition to the effect of the fifth invention.

According to the seventh invention, in the fifth and sixth inventions, the output frequency of the inverter is controlled so as not to change when the charging current of the storage battery provided on the DC bus exceeds a predetermined value. In addition to the effects of the fifth invention and the sixth invention, it is possible to prevent an excessive charging current from flowing to the storage battery and shortening the life.

According to the eighth aspect of the invention, the inverter is operated in synchronization with another AC power source, and when the voltage of the DC bus exceeds a predetermined value, the inverter is once made asynchronous and at a limited rate of change. The frequency is controlled so as to be lowered, the regenerative power from the regenerative load can be limited to the extent that it can be absorbed by the loss of the inverter, and the rise of the DC voltage can be prevented. , Asynchronous time can be shortened.

According to the ninth aspect of the invention, the inverter is operated in synchronization with another AC power source, and once the detected bypass frequency of another power source that operates in synchronization with the inverter drops by a predetermined value or more, the inverter is temporarily turned on. Since the frequency is controlled to be asynchronous and the frequency is lowered at a limited rate of change, in addition to the effect of the eighth invention, it is possible to prevent the stable operation of the uninterruptible power supply from being hindered by the extreme frequency fluctuation of the bypass power supply. Also, the asynchronous time can be shortened as compared with the sixth invention.

According to the tenth invention, in the eighth and ninth inventions, the output frequency of the inverter is reduced at a limited rate of change when the charging current of the storage battery provided on the DC bus exceeds a predetermined value. 8th and 9th
In addition to the effects of the invention, it is possible to prevent an excessive charging current from flowing to the storage battery and shorten the life, and to shorten the asynchronous time as compared with the seventh invention.

According to the eleventh aspect of the invention, in the uninterruptible power supply device which includes a rectifier and an inverter, and which supplies AC power to a load that is connected to the output side of the inverter and generates regenerative power, the DC voltage between the rectifier and the inverter is increased. Since the output frequency of the inverter is controlled to increase when the detected voltage of the bus bar becomes equal to or higher than a predetermined value, the regeneration of electric power from the regenerative load is eliminated, and the increase in DC voltage can be prevented.

According to the twelfth aspect of the invention, in the same configuration as the eleventh aspect of the invention, the output frequency and the output voltage of the inverter are controlled to rise when the detected voltage of the DC bus exceeds a predetermined value. As compared with the eleventh invention, it is possible to reliably prevent the regeneration of the load.

According to the thirteenth invention, the tenth and first
In a configuration similar to that of the first aspect of the invention, the inverter is operated in synchronization with another AC power source, and the output frequency of the inverter is controlled to increase when the frequency of the other power source decreases by a predetermined value or more. In addition to the effects of the invention, it is possible to prevent the stable operation of the uninterruptible power supply from being hindered by the frequency fluctuation of the bypass power supply.

Further, according to the fourteenth invention, as compared with the thirteenth invention, control is performed so as to increase the output frequency and the output voltage of the inverter when the frequency of another power source decreases by a predetermined value or more. Compared with, it is possible to reliably prevent the regeneration of the load.

Further, according to the fifteenth invention, in the eleventh to fourteenth inventions, the charging current of the storage battery provided on the DC bus between the rectifier and the inverter is detected, and the charging current by the detecting means is a predetermined value or more. Since the output frequency of the inverter is controlled so as to increase when it becomes low, in addition to the effects of the eleventh to fourteenth inventions, it is possible to prevent an excessive charging current from flowing to the storage battery and shortening the life.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a first embodiment according to the first invention.

FIG. 2 is a circuit diagram showing a second embodiment according to the second invention.

FIG. 3 is a circuit diagram showing a third embodiment according to the third invention.

FIG. 4 is a circuit diagram showing a fourth embodiment according to the fourth invention.

FIG. 5 is a circuit diagram showing a fifth embodiment according to the fifth to fifteenth inventions.

FIG. 6 is a circuit diagram showing a conventional example.

FIG. 7 is a circuit diagram showing a conventional example.

[Explanation of symbols]

 1B-1F Uninterruptible power supply 2 Rectifier 3 Inverter 4 Storage battery 5 Regenerative load 6 DC switch 7 Current detector 8 Voltage detector 9 / 9A Switching command device 10 Switch 11 Resistor 12 Current detection comparator 13 Voltage detection comparator 14 Frequency detection comparator 15 Switching command device 16 Frequency adjustment controller 17 Internal oscillator

Continuation of front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location H02P 3/18 101 D 8209-5H (72) Inventor Tetsuro Hashimoto 6-1-1 Hamayama-dori, Hyogo-ku, Kobe-shi, Hyogo No. Mitsubishi Electric Engineering Co., Ltd. Kobe Office (72) Inventor Hajime Kosaka 6-1-1 Hamayama-dori, Hyogo-ku, Kobe City, Hyogo Prefecture Mitsubishi Electric Engineering Co., Ltd. Kobe Office

Claims (15)

[Claims] 1. A rectifier for converting AC to DC, an inverter connected to the output side of the rectifier for converting the DC to AC again, and a storage battery connected to a DC bus between the rectifier and the inverter. In the uninterruptible power supply device, which is connected to the output side of the inverter and supplies AC power to a load that generates regenerative power, means for detecting a current flowing into the storage battery, and detecting the voltage of the DC bus. Means, a series circuit consisting of a switch and a resistor connected to the DC bus, and the switch is turned on when the inflow current or the DC bus voltage exceeds a predetermined value.
An uninterruptible power supply device, characterized in that means for bringing into an N state is provided, and the regenerative power generated by the regenerative load is consumed by the resistor. 2. The uninterruptible power supply according to claim 1, wherein the series circuit is connected not to the DC bus but to the AC output side of the inverter. 3. A rectifier for converting AC to DC, an inverter connected to the output side of the rectifier for converting the DC to AC again, and a DC bus between the rectifier and the inverter via a DC switch. In the uninterruptible power supply device, which is provided with a connected storage battery and supplies AC power to a load that is connected to the output side of the inverter and generates regenerative power, means for detecting the voltage of the DC bus bar, and the DC bus bar. A series circuit composed of a switch and a resistor to be connected, and means for turning on the switch when the DC bus voltage becomes a predetermined value or more are provided, and the regenerative electric power generated by the regenerative load is provided to the resistor. An uninterruptible power supply characterized by being consumed by. 4. The uninterruptible power supply according to claim 3, wherein the series circuit is connected not to the DC bus but to the AC output side of the inverter. 5. A rectifier for converting AC to DC, and an inverter connected to the output side of the rectifier for converting the DC to AC again, and connected to the output side of the inverter to generate regenerative power. In an uninterruptible power supply that supplies AC power to a load, the inverter operates in synchronization with another AC power supply, and voltage detection means for detecting the voltage of the DC busbar between the rectifier and the inverter, and the voltage of the DC busbar are An uninterruptible power supply comprising a control means for temporarily setting the inverter to be asynchronous and not changing the output frequency when the voltage exceeds a predetermined value. 6. A rectifier for converting AC into DC, and an inverter connected to the output side of the rectifier for converting the DC into AC again, and connected to the output side of the inverter to generate regenerative power. In an uninterruptible power supply that supplies AC power to a load, the inverter operates in synchronization with another AC power supply, and frequency detection means for detecting the bypass frequency of another power supply that operates in synchronization with the inverter, and the detected bypass frequency are An uninterruptible power supply comprising: a control means for temporarily setting the inverter to be asynchronous when the voltage drops by a predetermined value or more and not changing the output frequency. 7. A DC bus is provided with a storage battery, and current detection means for detecting a current flowing into the storage battery is provided.
The uninterruptible power supply device according to claim 5 or 6, wherein the control means does not change the output frequency of the inverter when the charging current of the storage battery exceeds a predetermined value. 8. A rectifier for converting alternating current to direct current and an inverter connected to the output side of the rectifier for converting the direct current to alternating current again, and connected to the output side of the inverter to generate regenerative power. In an uninterruptible power supply that supplies AC power to a load, the inverter operates in synchronization with another AC power supply, and voltage detection means for detecting the voltage of the DC busbar between the rectifier and the inverter, and the voltage of the DC busbar are An uninterruptible power supply comprising a control means for temporarily setting the inverter to be asynchronous when the voltage exceeds a predetermined value and lowering the frequency at a limited rate of change. 9. A rectifier for converting AC to DC, and an inverter connected to the output side of the rectifier for converting the DC to AC again, and connected to the output side of the inverter to generate regenerative power. In an uninterruptible power supply that supplies AC power to a load, the inverter operates in synchronization with another AC power supply, and frequency detection means for detecting the bypass frequency of another power supply that operates in synchronization with the inverter, and the detected bypass frequency are An uninterruptible power supply comprising: a control means for temporarily setting the inverter to be asynchronous when the voltage drops by a predetermined value or more and lowering the frequency at a limited rate of change. 10. A direct current bus is provided with a storage battery, and current detection means for detecting a current flowing into the storage battery is provided, wherein the control means outputs the output frequency of the inverter when the charging current of the storage battery becomes a predetermined value or more. 10. The uninterruptible power supply according to claim 8 or 9, characterized in that it is reduced at a limited rate of change. 11. A rectifier for converting AC into DC, and an inverter connected to the output side of the rectifier for converting the DC into AC again, and connected to the output side of the inverter to generate regenerative power. In an uninterruptible power supply that supplies AC power to a load, means for detecting the voltage of a DC bus between a rectifier and an inverter, and control for increasing the output frequency of the inverter when the detected voltage of the DC bus exceeds a predetermined value. An uninterruptible power supply characterized by comprising means. 12. A rectifier for converting AC to DC, and an inverter connected to the output side of the rectifier for converting the DC to AC again, and connected to the output side of the inverter to generate regenerative power. In an uninterruptible power supply that supplies AC power to a load, a means for detecting the voltage of the DC bus between the rectifier and the inverter, and an output frequency and an output voltage of the inverter when the detected voltage of the DC bus exceeds a predetermined value. An uninterruptible power supply comprising a control means for raising the temperature. 13. A rectifier for converting AC to DC, and an inverter connected to the output side of the rectifier for converting the DC to AC again, and connected to the output side of the inverter to generate regenerative power. In an uninterruptible power supply that supplies AC power to a load, the inverter operates in synchronization with another AC power supply, and frequency detection means for detecting a bypass frequency of another power supply that operates in synchronization with the inverter, and the other power supply. An uninterruptible power supply comprising: control means for increasing the output frequency of the inverter when the frequency of the power supply drops by a predetermined value or more. 14. A rectifier for converting AC to DC, and an inverter connected to the output side of the rectifier for converting the DC to AC again, and connected to the output side of the inverter to generate regenerative power. In an uninterruptible power supply that supplies AC power to a load, the inverter operates in synchronization with another AC power supply, and frequency detection means for detecting a bypass frequency of another power supply that operates in synchronization with the inverter, and the other power supply. An uninterruptible power supply comprising: a control means for increasing the output frequency and the output voltage of the inverter when the frequency of the power supply drops by a predetermined value or more. 15. A direct current bus between the rectifier and the inverter is provided with a storage battery, and a detection means for detecting a charging current of the storage battery is provided, and the control means is provided when the charging current by the detection means exceeds a predetermined value. The output frequency of the inverter is increased to increase the output frequency.
An uninterruptible power supply according to any one of 1.