JP2010074941A - Uninterruptible power supply apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an uninterruptible power supply apparatus that improves the efficiency of operation. <P>SOLUTION: The uninterruptible power supply apparatus 1, which is housed in a panel, includes: an inverter 7, which supplies a load equipment LD with AC power of constant voltage and constant frequency; a current transformer 21, which detects the output current of itself 1; a cooling fan 18, which cools the interior of the panel; an inverter 27 for cooling fan, which supplies the cooling fan 18 with AC power of variable voltage and variable frequency; and a control means 26, which intermittently operates the inverter 27 for cooling fan when the output current detected by the current transformer 21 is at or under a specified value. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an uninterruptible power supply.

In general, there is an uninterruptible power supply that converts AC power into DC power by a converter, converts the DC power to AC power by an inverter, and supplies the AC power to a load. In addition, there is known an uninterruptible power supply (UPS) in which such an uninterruptible power supply is housed in a panel and performs forced air cooling with a cooling fan (see, for example, Non-Patent Document 1).
MITSUBISHI 9700 Series UPS, Schematic Diagram List, [online], MITSUBISHI ELECTRIC POWER PRODUCTS, INC., [Search September 1, 2008], Internet <URL: http://www.meppi.com/Products/UninterruptiblePowerSupplies/Products /9700/9700_150kVA_Drawing.pdf>

  However, the uninterruptible power supply of the prior art document has the following problems.

  This uninterruptible power source is operating at a rating (maximum number of rotations) that does not change even when the cooling fan is unloaded. The inverter supplies AC power to the load facility and also supplies AC power for driving the cooling fan. For this reason, the inverter needs an output capacity obtained by adding the load facility capacity and the capacity of the cooling fan. These things reduce the operating efficiency of the uninterruptible power supply.

  Then, the objective of this invention is providing the uninterruptible power supply device which can improve driving | operation efficiency.

  An uninterruptible power supply according to an aspect of the present invention is an uninterruptible power supply housed in a storage space, and converts DC power into constant voltage and constant frequency AC power for supplying a load; and Current detection means for detecting an alternating current output from the uninterruptible power supply, a cooling fan for cooling the storage space, and the direct current power is changed to an alternating current power of variable voltage and variable frequency to drive the cooling fan. A cooling fan inverter for conversion and a control means for controlling the cooling fan inverter to operate intermittently when the amount of current detected by the current detection means is equal to or less than a predetermined value are provided.

  ADVANTAGE OF THE INVENTION According to this invention, the uninterruptible power supply device which can improve driving | operation efficiency can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a configuration diagram showing a configuration to which the uninterruptible power supply 1 according to the first embodiment of the present invention is applied. In addition, the same code | symbol is attached | subjected to the same part in subsequent figures, the detailed description is abbreviate | omitted, and a different part is mainly described. In the following embodiments, the same description is omitted.

  The uninterruptible power supply 1 includes a contactor 2, a fuse 3, an AC reactor 4, a converter 5, an electrolytic capacitor 6, an inverter 7, a transformer 8, a capacitor 9, a contactor 10, and a thyristor switch 12. , Contactor 13, contactor 15, fuse 16, cooling fan 18, current transformer 21, control circuit 26, cooling fan inverter 27, signal generation circuit 32, and setting device 37. . The uninterruptible power supply 1 is connected to receive control signals from the converter operation command circuit 24 and the inverter operation command circuit 25. The uninterruptible power supply 1 has an AC power supply P1 and a bypass power supply P2 connected to the input side. The uninterruptible power supply 1 is connected to a storage battery P3 for emergency of the AC power supply P1. The uninterruptible power supply 1 is connected to the load facility LD on the output side.

  The uninterruptible power supply 1 is a panel type device. The main body of the uninterruptible power supply 1 is housed inside the panel.

  The AC power supply P1 is a three-phase three-wire AC power supply. The AC power supply P1 is a power supply for supplying AC power to the uninterruptible power supply 1 at normal times. The AC power supply P1 is, for example, a commercial power supply or a private generator.

  The bypass power supply P2 is a three-phase three-wire AC power supply. The bypass power supply P2 is connected to the uninterruptible power supply 1 by a single-phase three-wire. The bypass power source P2 is a power source for supplying AC power to the uninterruptible power supply 1 when AC power is not supplied from the AC power source P1. The case where AC power is not supplied from the AC power supply P1 is, for example, when the AC power supply P1 is out of order or when the uninterruptible power supply 1 is being maintained. The AC power source P2 is, for example, a commercial power source or a private generator.

  The storage battery P3 is a DC power source. The storage battery P3 is a power source for supplying DC power to the uninterruptible power supply 1 at the time of a power failure of the AC power source P1.

  The load facility LD is connected to the uninterruptible power supply 1 by a single-phase three-wire. The load facility LD receives AC power from the uninterruptible power supply 1.

  Converter 5 converts AC power supplied from AC power supply P1 into DC power. The converter 5 supplies the converted DC power to the inverter 7 and the cooling fan inverter 27. The converter 5 is supplied with AC power from the AC power supply P <b> 1 through the contactor 2, the fuse 3, and the AC reactor 4 in order. The converter 5 receives a control signal such as an operation command or a stop command from the converter operation command circuit 24. In response to these control signals, the converter 5 is operated or stopped.

  The contactor 2 connects or disconnects the circuit according to a control signal from the converter operation command circuit 24. When the contactor 2 is inserted, AC power is supplied to the converter 5 from the AC power source P1. When the contactor 2 is turned off, AC power is not supplied to the converter 5 from the AC power supply P1.

  The fuse 3 is provided for protection against an AC current supplied from the AC power supply P1.

  The AC reactor 4 shapes the waveform of AC power from the AC power supply P1. That is, the AC reactor 4 is a filter reactor.

  The inverter 7 converts DC power into single-phase AC power having a constant voltage and a constant frequency. That is, the inverter 7 is a CVCF (constant voltage constant frequency) inverter. The inverter 7 supplies the converted AC power to the transformer 8. The inverter 7 is a device for converting DC power into AC power for supplying the load equipment LD. The inverter 7 is supplied with DC power from the converter 5. The inverter 7 is supplied with DC power from the storage battery P <b> 3 via the contactor 15 and the fuse 16. The inverter 7 receives a control signal such as an operation command or a stop command from the inverter operation command circuit 25. In response to these control signals, the inverter 7 is operated or stopped.

  The contactor 15 connects or disconnects a circuit for receiving supply of DC power from the storage battery P3. When the contactor 15 is inserted, the storage battery P3 DC power is supplied. When the contactor 15 is turned off, DC power is not supplied from the storage battery P3. The contactor 15 is turned on at the time of a power failure of the AC power supply P1.

  The fuse 16 is provided for protection against a direct current supplied from the storage battery P3.

  The electrolytic capacitor 6 is a smoothing capacitor for smoothing the DC power supplied to the inverter 7 or the cooling fan inverter 27.

  The transformer 8 is a step-up transformer (step-up transformer). The transformer 8 boosts the AC power supplied from the inverter 7. The transformer 8 supplies the boosted AC power to the load facility LD via the contactor 10. That is, the AC power output from the transformer 8 becomes an output as the uninterruptible power supply 1.

  The capacitor 9 shapes the waveform of the AC power output from the transformer 8. That is, the capacitor 9 is a filter capacitor.

  The contactor 10 connects or disconnects a circuit that outputs AC power from the transformer 8. When the contactor 10 is inserted, AC power from the transformer 8 is output. When the contactor 10 is turned off, AC power from the transformer 8 is not output. The contactor 10 is cut when the AC power is output as the uninterruptible power supply 1 from the bypass power supply P2.

  The cooling fan inverter 27 converts DC power into AC power having a variable voltage and variable frequency. That is, the cooling fan inverter 27 is a VVVF (variable voltage variable frequency) inverter. The relationship between the output voltage V and the output frequency F of the cooling fan inverter 27 is as follows.

V / F 一定 Constant The cooling fan inverter 27 supplies the converted AC power to the cooling fan 18. The input side of the cooling fan inverter 27 and the input side of the inverter 7 are electrically connected. Therefore, the cooling fan inverter 27 is supplied with DC power in the same manner as the inverter 7. The cooling fan inverter 27 outputs AC power under the control of the control circuit 26.

  The cooling fan 18 is driven by AC power converted by the cooling fan inverter 27. The rotational speed of the cooling fan 18 is proportional to the output frequency of the cooling fan inverter 27. When the cooling fan 18 is driven, the inside of the panel (storage space) in which the uninterruptible power supply 1 is stored is cooled.

  The thyristor switch 12 is provided between the circuit of the input side of the uninterruptible power supply 1 connected to the bypass power supply P2 and the output side of the uninterruptible power supply 1 connected to the load facility LD. The thyristor switch 12 is a semiconductor switch for switching the output of AC power as the uninterruptible power supply device 1 from AC power output from the inverter 7 to AC power supplied from the bypass power supply P2 at high speed.

  The contactor 13 is connected in parallel with the thyristor switch 12. The contactor 13 is provided in order to maintain the AC power supplied from the bypass power supply P <b> 2 as the output of the uninterruptible power supply 1.

  The current transformer 21 is provided for detecting the output current of the uninterruptible power supply 1. The current transformer 21 inputs the detected current to the control circuit 26 and the signal generation circuit 32 as a current feedback signal.

  The control circuit 26 outputs an operation command or a stop command to the cooling fan inverter 27. The control circuit 26 controls the cooling fan inverter 27 based on the current feedback signal received from the current transformer 21 and the operation frequency command signal received from the signal generation circuit 32.

  The signal generation circuit 32 receives a current feedback signal from the current transformer 21. The signal generation circuit 32 receives the setting value from the setting device 37. The signal generation circuit 32 generates an operation frequency command signal based on the current feedback signal and the set value. The signal generation circuit 32 transmits the generated operation frequency command signal to the control circuit 26.

  The setting unit 37 sets a setting value for comparison with the current feedback signal received from the current transformer 21 by the signal generation circuit 32. The setter 37 can set an arbitrary set value.

  Next, the operation of the signal generation circuit 32 will be described.

  The signal generation circuit 32 receives the set value set in the setting device 37.

  The signal generation circuit 32 compares the current feedback signal received from the current transformer 21 with the set value received from the setter 37.

  When the current feedback signal is lower than the set value, the signal generation circuit 32 generates an operation frequency command signal that causes the cooling fan inverter 27 to operate intermittently. Here, the intermittent operation is an operation in which the cooling fan inverter 27 is repeatedly operated and stopped. When the signal generation circuit 32 outputs an operation frequency command signal for intermittent operation to the control circuit 26, the control circuit 26 performs control for intermittent operation of the cooling fan inverter 27.

  When the current feedback signal is higher than the set value, the signal generation circuit 32 generates an operation frequency command signal of an inclination signal that reaches the current feedback signal after a preset time. When the signal generation circuit 32 outputs an operation frequency command signal of the inclination signal to the control circuit 26, the control circuit 26 performs control to gradually increase the output frequency of the cooling fan inverter 27.

  Next, the operation of the control circuit 26 will be described.

  The control circuit 26 receives the operation command from the converter operation command circuit 24, and outputs the operation command to the cooling fan inverter 27 when the current feedback signal received from the current transformer 21 exceeds a predetermined current value. As a result, the cooling fan inverter 27 starts operation.

  When the operation of the cooling fan inverter 27 is started, the control circuit 26 generates an output voltage / frequency transmission command for controlling the cooling fan inverter 27. The control circuit 26 generates an output voltage / frequency transmission command based on the operation frequency command signal received from the signal generation circuit 32. The output voltage / frequency transmission command is generated in proportion to the current feedback signal received from the current transformer 21.

  The control circuit 26 outputs the generated transmission command to the cooling fan inverter 27. With this transmission command, the control circuit 26 controls the AC power output from the cooling fan inverter 27.

  According to this embodiment, the following effects can be obtained.

  The uninterruptible power supply 1 is provided with a cooling fan inverter 27 that is a VVVF inverter exclusively as a driving power source for the cooling fan 18. Thereby, the output capacity of the inverter 7 for supplying to the load equipment LD does not need to satisfy the capacity of the cooling fan 18 in addition to the capacity of the load equipment LD. Thereby, the inverter 7 can select the output capacity more suitable for the load equipment LD.

  Further, the control circuit 26 generates an output voltage / frequency transmission command for controlling the inverter 27 so as to be proportional to the current feedback signal of the output current detection current transformer 21 of the uninterruptible power supply 1. The cooling fan inverter 27 is controlled by this transmission command. For this reason, when the output current of the uninterruptible power supply 1 is small, the operating frequency of the cooling fan 18 is also lowered. That is, the rotation speed of the cooling fan 18 is low. The power consumption of the cooling fan 18 is proportional to the cube of the rotational speed. Therefore, the power saving operation of the cooling fan 18 can be performed. As a result, the power consumption of the uninterruptible power supply 1 can be reduced. Therefore, the uninterruptible power supply 1 can operate with high efficiency.

  Further, by providing the signal generation circuit 32, the cooling fan inverter 27 can be intermittently operated when the current feedback signal is lower than the set value. On the other hand, when the current feedback signal is higher than the set value, the output of the cooling fan inverter 27 can be gradually increased.

  For example, when the uninterruptible power supply 1 is activated, the output current of the uninterruptible power supply 1 is “0” when the inverter 7 is stopped and only the converter 5 is activated. For this reason, the amount of heat generated by the uninterruptible power supply 1 is small. In such a state, there is almost no need to cool the inside of the board. Therefore, in such a state, the cooling fan 18 may be stopped or finely moved. For this reason, the cooling fan 18 is intermittently operated by the signal generation circuit 32. In the uninterruptible power supply 1, as the inverter 7 is activated and the output current of the uninterruptible power supply 1 increases, the rotation speed of the cooling fan 18 increases in proportion. Thus, since the uninterruptible power supply 1 does not increase the rated rotational speed when the load capacity is less than the rated capacity, the power consumption can be reduced.

  Further, the life of the cooling fan 18 is almost determined by the rated rotational speed × time. For this reason, the lifetime (time) can be extended by reducing the rotation speed of the cooling fan 18 as needed.

  Furthermore, by providing the signal generation circuit 32, the cooling fan 18 performs soft start or intermittent operation according to the output frequency of the cooling fan inverter 27. Thereby, the life of the cooling fan 18 can be further extended.

(Second Embodiment)
FIG. 2 is a block diagram showing a configuration to which the uninterruptible power supply 1A according to the second embodiment of the present invention is applied.

  The uninterruptible power supply 1A has a configuration in which a limiter command circuit 29 is added to the uninterruptible power supply 1 according to the first embodiment shown in FIG. Other points are the same as the uninterruptible power supply 1.

  The limiter command circuit 29 is a circuit for maintaining the output frequency of the cooling fan inverter 27 at least at the minimum output frequency regardless of the current feedback signal of the current transformer 21. That is, the limiter command circuit 29 always sets the output frequency of the cooling fan inverter 27 to a minimum output frequency or higher regardless of the amount of current output from the uninterruptible power supply 1A. The limiter command circuit 29 can arbitrarily set a minimum output frequency.

  The limiter command circuit 29 outputs a limiter command to the signal generation circuit 32. The signal generation circuit 32 generates an operation frequency command signal based on this limiter command. With this operation frequency command signal, the control circuit 26 controls the cooling fan inverter 27 so that the operation frequency of the cooling fan 18 does not fall below the minimum operation frequency. Thereby, for example, even when there is no load, the cooling fan 18 rotates at a rotational speed equal to or higher than the set value set by the limiter command circuit 29.

  According to the present embodiment, in addition to the operational effects of the first embodiment, the following operational effects can be obtained.

  By providing the limiter command circuit 29, even if the output current of the uninterruptible power supply 1A is small, the cooling fan inverter 27 can maintain at least the minimum output frequency. Thereby, uninterruptible power supply 1A can always maintain the number of rotations of cooling fan 18 above a predetermined number of rotations.

  Therefore, the uninterruptible power supply 1A can prevent a failure due to insufficient cooling in the panel by always rotating the cooling fan 18 at a predetermined rotation speed or higher. Thereby, the reliability of the uninterruptible power supply 1A can be improved.

(Third embodiment)
FIG. 3 is a configuration diagram showing a configuration to which the uninterruptible power supply 1B according to the third embodiment of the present invention is applied.

  In the uninterruptible power supply 1 according to the first embodiment shown in FIG. 1, the uninterruptible power supply 1 </ b> B is provided with a control circuit 26 </ b> B instead of the control circuit 26, and the power input of the inverter 7 and the cooling fan 18. Is added, and contactors 33 and 34 are added. Other points are the same as the uninterruptible power supply 1.

  The contactor 33 is inserted into an electrical path connecting the output side of the cooling fan inverter 27 and the power input of the cooling fan 18. The contactor 33 connects or disconnects the circuit according to a control signal from the control circuit 26B. When the contactor 33 is inserted, AC power is supplied from the cooling fan inverter 27 to the cooling fan 18. When the contactor 33 is turned off, AC power is not supplied from the cooling fan inverter 27 to the cooling fan 18. Normally, the contactor 33 is inserted. When the cooling fan inverter 27 is out of order, the contactor 33 is disconnected.

  The contactor 34 is inserted in an electrical path that connects the output side of the inverter 7 and the power input of the cooling fan 18. The contactor 34 connects or disconnects the circuit according to a control signal from the control circuit 26B. When the contactor 34 is inserted, AC power is supplied from the inverter 7 to the cooling fan 18. When the contactor 34 is turned off, AC power is no longer supplied from the inverter 7 to the cooling fan 18. Normally, the contactor 34 is cut off. The contactor 34 is inserted when the cooling fan inverter 27 fails.

  The control circuit 26B adds a function of controlling the contactors 33 and 34 to the function of the control circuit 26 of the first embodiment. The other points are the same as those of the control circuit 26.

  When the control circuit 26B detects a failure of the cooling fan inverter 27, the control circuit 26B turns off the contactor 33 and turns on the contactor 34. Thus, the cooling fan 18 is supplied with AC power instead of the cooling fan inverter 27 instead of the inverter 7. The detection of the failure of the cooling fan inverter 27 may be received by receiving a failure detection signal from the cooling fan inverter 27 or may be determined by a detection signal from another device.

  According to the present embodiment, in addition to the operational effects of the first embodiment, the following operational effects can be obtained.

  The uninterruptible power supply 1B has a configuration in which the power supplied to the cooling fan 19 is switched from the cooling fan inverter 27 to the inverter 7 due to a failure of the cooling fan inverter 27 or the like. Thus, even when the cooling fan inverter 27 cannot normally output AC power due to a failure or the like, the uninterruptible power supply 1B continues to drive the cooling fan 18 with the AC power output from the inverter 7. can do. Thereby, even if the cooling fan inverter 27 breaks down, it is possible to prevent a failure due to insufficient cooling in the panel. Thereby, the reliability of the uninterruptible power supply 1B can be improved.

(Fourth embodiment)
FIG. 4 is a configuration diagram showing a configuration to which the uninterruptible power supply 1C according to the fourth embodiment of the present invention is applied.

  The uninterruptible power supply 1C has a configuration in which a circuit equivalent to the limiter command circuit 29 of the second embodiment is added to the uninterruptible power supply 1B according to the third embodiment shown in FIG. Other points are the same as the uninterruptible power supply 1B.

  The limiter command circuit 29 is a circuit for maintaining the output frequency of the cooling fan inverter 27 at least at the minimum output frequency regardless of the current feedback signal of the current transformer 21. That is, the limiter command circuit 29 always sets the output frequency of the cooling fan inverter 27 to a minimum output frequency or higher regardless of the amount of current output from the uninterruptible power supply 1C. The limiter command circuit 29 can arbitrarily set a minimum output frequency. The limiter command circuit 29 outputs a limiter command to the control circuit 26B. Thereby, the control circuit 26B controls the cooling fan inverter 27 so that the operating frequency of the cooling fan 18 does not fall below the minimum operating frequency. Thereby, for example, even when there is no load, the cooling fan 18 rotates at a rotational speed equal to or higher than the set value set by the limiter command circuit 29.

  According to the present embodiment, in addition to the functions and effects of the third embodiment, the following functions and effects can be obtained.

  By providing the limiter command circuit 29, the cooling fan inverter 27 can maintain at least the minimum output frequency even when the output current of the uninterruptible power supply 1C is small. Thereby, 1 C of uninterruptible power supplies can always maintain the rotation speed of the cooling fan 18 more than predetermined rotation speed.

  Therefore, the uninterruptible power supply 1C can prevent a failure due to insufficient cooling in the panel by always rotating the cooling fan 18 at a predetermined rotation speed or higher. Thereby, the reliability of the uninterruptible power supply 1C can be improved.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

The block diagram which shows the structure which applied the uninterruptible power supply which concerns on the 1st Embodiment of this invention. The block diagram which shows the structure which applied the uninterruptible power supply which concerns on the 2nd Embodiment of this invention. The block diagram which shows the structure which applied the uninterruptible power supply which concerns on the 3rd Embodiment of this invention. The block diagram which shows the structure which applied the uninterruptible power supply which concerns on the 4th Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Uninterruptible power supply device, 2 ... Contactor, 3 ... Fuse, 4 ... AC reactor, 5 ... Converter, 6 ... Electrolytic capacitor, 7 ... Inverter, 8 ... Transformer, 9 ... Capacitor, 10 ... Contactor, 12 ... Thyristor switch , 13 ... contactor, 15 ... contactor, 16 ... fuse, 18 ... cooling fan, 21 ... current transformer, 24 ... converter operation command circuit, 25 ... inverter operation command circuit, 26 ... control circuit, 27 ... inverter for cooling fan, 32 ... Signal generation circuit, 37 ... Setting device, LD ... Load equipment, P1 ... AC power supply, P2 ... Bypass power supply, P3 ... Storage battery.

Claims (7)

An uninterruptible power supply housed in a storage space,
An inverter that converts DC power into AC power of constant voltage and constant frequency for supplying to the load;
Current detection means for detecting an alternating current output from the uninterruptible power supply,
A cooling fan for cooling the storage space;
In order to drive the cooling fan, an inverter for cooling fan that converts the DC power into AC power with variable voltage and variable frequency;
An uninterruptible power supply comprising: control means for controlling the cooling fan inverter to intermittently operate when the amount of current detected by the current detection means is less than or equal to a predetermined value. When the amount of current detected by the current detection unit is greater than the predetermined value, the control unit changes the AC power output from the cooling fan inverter according to the amount of current detected by the current detection unit. The uninterruptible power supply according to claim 1. The uninterruptible power supply apparatus according to claim 1 or 2, further comprising a converter that converts AC power supplied from an AC power source into DC power for supplying to the inverter. The uninterruptible power supply according to any one of claims 1 to 3, further comprising a storage battery that supplies direct-current power to be supplied to the inverter. A bypass power supply for supplying AC power to the load by bypassing a path not through the inverter;
The switching means for switching the AC power supplied to the load from the AC power output from the inverter to the AC power supplied from the bypass power source is provided. The uninterruptible power supply according to any one of the items. 6. The apparatus according to claim 1, further comprising a path forming unit configured to form a path for supplying AC power output from the inverter to the cooling fan when the cooling fan inverter is abnormal. Uninterruptible power supply as described in the section. 7. The control unit according to claim 1, wherein the control unit controls AC power output from the cooling fan inverter so as not to reduce an operating frequency of the cooling fan to a predetermined value or less. Uninterruptible power supply as described in the section.

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