JP2011055570A - Uninterruptible power supply device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an uninterruptible power supply device which improves an input power factor of the whole facility toward unity without a reactive power compensator. <P>SOLUTION: The uninterruptible power supply device with a rectifier (converter) receiving sinusoidal voltages and currents allows variable reactive power inputs. The uninterruptible power supply device allowing variable reactive power inputs compensates the reactive power of a load parallelly connected to the input side of the uninterruptible power supply device and adjusts the input power factor of the whole facility. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an uninterruptible power supply for inputting an alternating voltage / current.

  In an uninterruptible power supply that has a rectifier (converter) that converts sine wave voltage and current into DC power and an inverter that converts DC power into AC power, the load of the uninterruptible power supply The input power factor of the uninterruptible power supply can be set to an arbitrary value regardless of the power factor. This is because only the active power is transmitted in the DC circuit between the rectifier and the inverter, the reactive power on the input side of the uninterruptible power supply is only for rectifier operation, and the reactive power on the load side of the uninterruptible power supply is This is because it depends only on driving.

  In such an uninterruptible power supply, control is often performed so that the input power factor of the rectifier (converter) is 1. This depends on the equipment capacity and current of the equipment on the input side of the uninterruptible power supply by minimizing the apparent input power, that is, by minimizing the input current equivalent to the active power equivalent to the load. This is because the loss to be reduced is minimized.

  On the other hand, when considering other load devices connected in parallel to the input side of the uninterruptible power supply, there are devices with a delay power factor such as a power load and devices with a leading power factor such as a combination of a diode rectifier and a smoothing capacitor. Therefore, the input power factor of the entire facility is not necessarily 1, and the input apparent power is larger than the necessary active power.

  FIG. 1 is an example of equipment including a conventional uninterruptible power supply. In this conventional example, an input power source 1, an input-side power distribution device 2, an uninterruptible power supply 3, a rectifier 4, an inverter 5, a load of the uninterruptible power supply 6, a load device 7 connected in parallel with the uninterruptible power supply are shown. Yes. The input power factor of the rectifier 4 of the uninterruptible power supply 3 is 1, the input power factor of the load device 7 connected in parallel with the uninterruptible power supply 3 is advanced, and the input power factor of the entire facility is advanced. ing.

  FIG. 2 shows the input power of the entire equipment with respect to the circuit configuration of FIG. 1 in order to reduce the equipment capacity of the input power source 1 and the input side power distribution equipment 2 and to reduce the loss of the input side power distribution equipment 2. It is an example of the installation which added the reactor 8 for the reactive power compensation for making a rate 1. The input power factor of the rectifier 4 of the uninterruptible power supply 3 is 1, and the input power factor of the load device 7 connected in parallel with the uninterruptible power supply 3 is advanced, whereas the reactor 8 for reactive power compensation Thus, the reactive power compensation is performed so as to cancel the reactive power of the load device 7, so that the input power factor of the entire facility approaches 1.

  In the example of FIG. 2, the reactive power compensation reactor 8 is added for power factor adjustment. However, a reactive power compensation device composed of a reactive power compensation capacitor, a semiconductor power converter, or the like may be added. .

JP-A-2-100116

  In the above prior art, in order to set the input power factor of the entire facility to 1, it is necessary to add a reactive power compensation device to the facility. In this case, problems such as an increase in equipment cost for reactive power compensation equipment, expansion of installation space, and loss for reactive power compensation equipment occur.

  An object of the present invention is to set the input power factor of the entire facility to 1 without adding reactive power compensation equipment.

  In order to achieve the above object, the present invention is characterized in that the input reactive power is made variable in an uninterruptible power supply apparatus including a converter that receives AC voltage / current as an input.

  Furthermore, in the uninterruptible power supply, the present invention provides an uninterruptible power supply so that the input apparent power of the entire facility consisting of the uninterruptible power supply and other load equipment connected in parallel to the input side of the uninterruptible power supply is minimized. It is characterized by automatically adjusting the input reactive power of the device.

  Furthermore, the present invention provides a control device for an uninterruptible power supply, wherein the control device calculates the input power from the current flowing into the uninterruptible power supply and the input voltage of the converter (the reactive power component is minimized). Thus, the reactive power input of the uninterruptible power supply is adjusted.

  According to the uninterruptible power supply of the present invention, by making the reactive power input of the uninterruptible power supply variable, compensate the reactive power of the load equipment connected in parallel to the input side of the uninterruptible power supply, It is possible to adjust the input power factor of the entire facility.

  Further, according to the uninterruptible power supply of the present invention, the power factor of the entire facility is automatically changed by automatically changing the reactive power input of the uninterruptible power supply so that the total reactive power input of the entire facility is minimized. Is 1, it is possible to reduce the installed capacity of the input power supply and the input-side distribution device, and to reduce the loss of the input-side distribution device.

It is an example of the installation containing the conventional uninterruptible power supply. It is an example of the installation which added the reactor 8 for reactive power compensation to the circuit structure of FIG. In the embodiment of claim 1 of the present invention, the reactive power compensation is performed by the uninterruptible power supply so that the reactive power of the entire equipment is minimized. It is an example of the rectifier (converter) of an uninterruptible power supply, and its equivalent circuit. FIG. 5 is a relationship among voltage, current, and power in each operation of the rectifier (converter) in FIG. 4. In the embodiment of claim 2 of the present invention, the reactive power compensation is automatically performed by the uninterruptible power supply so that the reactive power of the entire equipment is minimized.

  FIG. 3 shows a first embodiment of the present invention.

  In this embodiment, an input power source 1, an input-side power distribution device 2, an uninterruptible power supply device 3, a rectifier 4, an inverter 5, a load of the uninterruptible power supply device 6, a load device 7 connected in parallel with the uninterruptible power supply device are shown. ing. In this embodiment, the input power factor of the load equipment connected in parallel with the uninterruptible power supply is advancing. The uninterruptible power supply is operated so that reactive power of the load equipment 7 connected in parallel and reactive power of the same magnitude flows in reverse with the advance delay. As a result, the input power factor of the entire facility is close to 1, and the facility capacity of the input power source 1 and the input-side power distribution device 2 is further reduced.

  FIG. 4 shows a configuration example of a rectifier (converter) of an uninterruptible power supply apparatus according to an embodiment of the present invention and an equivalent circuit thereof.

  This rectifier (converter) is a combination of a reactor and a sine wave voltage source, and has a function of adjusting active power and reactive power by adjusting the phase and amplitude of the sine wave voltage source.

  FIG. 5 shows an example of voltage, current, and power in each operation of the rectifier (converter) of FIG.

  FIG. 5A shows only active power as input, and FIG. 5B shows only reactive power as input.

  In conventional rectifiers (converters), this circuit configuration was controlled so that only reactive power was allowed to flow, but reactive power was maintained with the same hardware circuit configuration simply by changing the control point. Can be realized. That is, the reactive power compensation is realized without particularly adding hardware devices.

  FIG. 6 is an example of a facility that automatically compensates reactive power by the uninterruptible power supply so that the reactive power of the entire facility is minimized in the second embodiment of the present invention. The current detection element 9 is provided for the input of the entire facility, and the control device 10 calculates the input power from the current of this portion and the input voltage of the rectifier (converter) of the uninterruptible power supply, and the reactive power among these Adjust the reactive power input of the uninterruptible power supply so that the minutes are minimized. As a result, the reactive power of the entire facility is minimized.

  In this example, the power of the entire facility is detected, but it is equipped with power detection means that detects the power of the load equipment connected in parallel with the uninterruptible power supply, and the uninterruptible power supply is disabled from the detected power state. It is also possible to adjust the power input. Further, the voltage detection for calculating the power can be realized by using a voltage detector independent of the uninterruptible power supply.

DESCRIPTION OF SYMBOLS 1 Input power supply 2 Input side power distribution equipment 3 Uninterruptible power supply 4 Rectifier 5 Inverter 6 Uninterruptible power supply load 7 Load equipment 8 Reactive power compensation reactor 9 Current detection element 10 Control device

Claims (3)

In an uninterruptible power supply with a converter that accepts AC voltage and current as input,
An uninterruptible power supply characterized by variable input reactive power. The uninterruptible power supply according to claim 1,
The input reactive power of the uninterruptible power supply is automatically adjusted so that the apparent input power of the entire facility consisting of the load equipment connected in parallel to the input side of the uninterruptible power supply and the uninterruptible power supply is minimized. An uninterruptible power supply. The uninterruptible power supply according to claim 2,
Reactive power input of the uninterruptible power supply so that the reactive power component is minimized by calculating the input power from the controller and the current flowing into the uninterruptible power supply and the device (input power from the converter input voltage) An uninterruptible power supply characterized by adjusting.

Images