JP2001211651A - Inverter air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a full-wave voltage doubler rectifying circuit for an inverter air conditioner which enables labor saving. SOLUTION: A power-saving improving reactor 12 is arranged in series to a power source 11, and is connected on a DC output side to metallized film capacitors 14, 15 for a voltage doubler and a smoothing capacitor 15, through full-wave rectifying diodes of parallel-connected two diodes formed by short- circuiting the AC side of a diode bridge 13, and a full-wave voltage doubler rectifying circuit is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inverter air conditioner provided with a power supply circuit effective for labor saving.

[0002]

2. Description of the Related Art Conventionally, a full-wave voltage doubler rectifier circuit is mounted on a 100 V inverter air conditioner. As shown in FIG. 4, a power factor improving reactor 2 is arranged in series with an AC power supply 1, full-wave rectified by bridge diodes 3 and 4, and a doubled voltage is obtained by electrolytic capacitors 5 and 6. For protection of the electrolytic capacitors 5 and 6, a method of arranging diodes 7 and 8 of a bridge diode at respective charging terminals of the electrolytic capacitors 5 and 6 and smoothing the electrolytic capacitors 9 is adopted. Also, apart from the conventional inverter air conditioner full-wave voltage doubler rectifier circuit, Japanese Patent Application Laid-Open No. 63-2348
As disclosed in Japanese Unexamined Patent Publication No. 66-66, a situation has been reached in which a metallized film capacitor can be used as a voltage doubler capacitor.

[0003]

SUMMARY OF THE INVENTION In inverter air conditioners, further labor saving is demanded. An object of the present invention is to provide an inverter air conditioner having a full-wave voltage doubler rectifier circuit capable of saving power.

[0004]

In order to solve the above-mentioned problems, the present invention uses a metallized film capacitor as a voltage doubler capacitor and uses it as a rectifying diode having two bridge diodes connected in parallel. This employs a full-wave voltage doubler rectifier circuit.

[0005]

The invention according to claim 1 of the present invention comprises at least a bridge diode, a voltage doubler capacitor, a smoothing capacitor, and a power factor improving reactor.
A metallized film capacitor is used as the voltage doubler capacitor, and a diode for voltage doubler capacitor protection in the bridge diode is used as a full-wave rectifier diode that is connected in parallel two by two. The current flowing through the diode is halved, and the loss of the diode section can be reduced by half.

According to a second aspect of the present invention, an iron cored reactor is used as a power factor improving reactor, a tap is provided in a winding, a change in input current is detected, and a tap of the reactor is switched by a switch. By switching, the inductance suitable for the input current can be set, the DC conversion efficiency at the time of switching can be improved, and the copper loss and iron loss of the reactor can be reduced.

(Embodiment 1) FIG. 1 is a diagram of a full-wave voltage doubler rectifier according to claim 1, wherein a power factor improving reactor 12 is arranged in series with an AC power supply 11, and an AC
Through a two-parallel full-wave rectifying diode having a short-circuited side, the DC output side is connected to metallized film capacitors 14 and 15 for voltage doubler and a smoothing capacitor 16.

According to the above configuration, by using the metallized film capacitors 14 and 15 having no polarity as the voltage doubler capacitor, even if a reverse bias voltage is applied,
Unlike an electrolytic capacitor, reliability is not lost.

As a result, two reverse bias voltage protection diodes which have been conventionally used are not required. However, considering heat dissipation, it is more economical to use a commercially available bridge diode. Therefore, by effectively utilizing the two unnecessary diodes and using them as two parallel-connected full-wave rectifier diodes in which the AC side of the diode 13 is short-circuited, the current flowing through each rectifier diode is reduced. Is １ ／, and the loss of the diode section can be reduced by half.

(Embodiment 2) FIG. 2 is a diagram of a full wave voltage doubler rectifier circuit according to a second embodiment. The reactor 17 with a power factor improving iron core connected in series with the power supply 11 is provided with taps in the windings, and the interfaces of the windings are L1, L
2 and L3. Further, a magnet relay switch 18 is connected in parallel with L2 and L3 to detect an input current of the inverter air conditioner, and to short-circuit L2 and L3 of the reactor 17 at a set input current or less. Note that the subsequent configuration is the same as in the first embodiment, and a description thereof will be omitted.

According to the above configuration, the input current is limited.
Both an appropriate inductance value for the maximum output of the inverter air conditioner that requires a power factor improvement and an inductance value suitable for an output used for a long time at home can be selected.

As shown in the output voltage characteristic diagram of FIG. 3, if the current set value for short-circuiting between L2 and L3 of the reactor 17 is set to the input current I1 corresponding to the output used for a long time at home, the output voltage Vdc , The conversion efficiency to DC is improved, and the copper loss is reduced due to the decrease in the DC resistance of the winding of the reactor 17, and the iron loss is also reduced due to the decrease in the magnetic flux density of the iron core. The appropriate inductance value varies depending on the maximum output of the inverter air conditioner. The former is effective at 4 to 7 mH, and the latter is effective at 2 to 5 mH.

The same effect can be obtained by connecting two power factor improving reactors in series and opening and closing one of the reactors with a switch.

[0014]

According to the first aspect of the invention, by connecting two rectifying diodes in parallel, the loss generated in the rectifying diode can be reduced by half.

According to the second aspect of the present invention, a tap is provided in the winding of the reactor, a change in the input current is detected, and the inductance is switched by a switch. It is possible to improve the conversion efficiency and reduce the loss generated in the reactor.

[Brief description of the drawings]

FIG. 1 is a full-wave voltage doubler rectifier circuit diagram of an inverter air conditioner according to a first embodiment of the present invention.

FIG. 2 is a full-wave voltage doubler rectifier circuit diagram of the inverter air conditioner according to the second embodiment of the present invention.

FIG. 3 is an output voltage characteristic diagram

FIG. 4 is a full-wave voltage doubler rectifier circuit diagram of a conventional inverter air conditioner.

[Explanation of symbols]

 12, 17 Reactor for power factor improvement 13 Bridge diode 14, 15 Metallized film capacitor for double voltage 16 Smoothing capacitor 18 Magnet relay switch

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H02M 7/48 H02M 7/48 Z

Claims (2)

[Claims] An at least one bridge diode, a voltage doubler capacitor, a smoothing capacitor, and a power factor improving reactor, wherein a metallized film capacitor is used as the voltage doubler capacitor, and two of the bridge diodes are connected in parallel. An inverter air conditioner comprising a full-wave voltage doubler rectifier circuit used as a connected rectifier diode. 2. The reactor according to claim 1, wherein an iron cored reactor is used as the power factor improving reactor, a tap is provided in the winding, a change in the input current is detected, and the tap of the reactor is switched by a switch. Inverter air conditioner as described.