Power supply device and air conditioner using the same

Abstract

This invention provides a power supply device capable of widening a conduction period of an input current by a simple control to improve a power factor, and reducing a harmonic distortion of the input current The power supply device comprises a rectifier circuit, a reactor, a power factor correction circuit having switching elements, capacitors and a reverse-current blocking rectifier elements, a smoothing capacitor for smoothing an output voltage of the power factor correction circuit to obtain a DC voltage, a pulse signal controller generating and outputting a pulse signal for turning on and off the switching elements, and a driver for receiving the pulse signal to drive a switching elements of the power factor correction circuit.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to a power supply device which converts an alternating current into a DC, and reduces a harmonic distortion of an input current so as to improve a power factor.[0003]2. Description of the Related Art[0004]Conventionally, a capacitor input type rectifier circuit has been used as an AC-to-DC converter circuit in various fields. The capacitor input type rectifier circuit inputs an AC voltage to a diode rectifier circuit so as to obtain a ripple voltage output, and smoothens the ripple voltage output by a capacitor so as to obtain a DC voltage. However, in the capacity input type rectifier circuit, a conduction period of an input current becomes narrow, and then, a power factor is worsened, and further, a reactive power is much. For this reason, it is not possible to effectively use a power, and the input current contains much harmonic distortions, as a result, there is a problem of fault to eq...

AI Technical Summary

Benefits of technology

[0019]The present invention has been made in order to solve the aforesaid problem in the prior art. It is, therefore, an object of the present invention to provide a power supply device which can obtain high power factor with a simple construction and control without carrying out high frequency switching, prevent an increase of loss in a filter circuit resulting from an increase of loss in a switching element and an increase of switching noise, and can restrict a harmonic and a loss.

[0021]Further, :mother object of the present invention is to provide an power supply device which can prevent an increase in a size of reactor in an input of 200V, and an increase of loss resulting from the increase of the reactor size, and can prevent a switching element from being made into a large size. In addition, another object of the present invention is to provide a power supply device which can greatly change an output voltage even if a switching control is simplified, and can obtain a sufficient power factor.

[0025]In the power supply device according to the present invention, a wide conduction period can be obtained to restrict a harmonic distortion, and realize a power supply device which can reduce a switching noise and a loss by a simple construction and control. Further the power supply device according to the present invention provides a low-loss air conditioner which has high power factor and can restrict a harmonic distortion.

Problems solved by technology

However, in the capacity input type rectifier circuit, a conduction period of an input current becomes narrow, and then, a power factor is worsened, and further, a reactive power is much.

For this reason, it is not possible to effectively use a power, and the input current contains much harmonic distortions, as a result, there is a problem of fault to equipment connected to the identical power supply device.

However, in the above power supply device shown in FIG. 31A, its improvement effect is low although the power supply device can improve a power factor with a simple construction and a sufficient power factor can not be obtained.

Since a reactor value must be made large in order to obtain high power factor with the circuit construction, it causes a problem that components would be made into a large size and a loss would simultaneously increase.

Even though the above power supply device shown in FIG. 32A can form the input current into a shape of sine wave and control a power factor to approximately 1, the power supply device has the following problems.

More specifically, the control becomes complicate, and a loss in the switching element 107 is increased due to high frequency switching accompanying with waveform shaping, and further, a switching noise increases.

This causes a cost increase, an increase of loss in the filter circuit, and finally efficiency deterioration as a whole.

However, the control becomes complicate, because both of a delay time and a pulse width must be controlled.

Further, in the case where the above power supply device is applied to an air conditioner or the like, the reactor is made into a large size in inputting 200V, and then, a loss is increased in the large-sized reactor.

Further, since a voltage applied to switching means becomes high, a component having a high withstand voltage is required.

As a result, the component is made into a large size, and a switching loss becomes great in the switching element 107.

This power supply device however has the following problems.

More specifically, as shown in FIG. 34B, when an output voltage increases, a voltage boost ratio becomes higher, and the power supply device is close to the voltage double rectifier circuit Consequently a sufficient power factor can not be obtained.

It is impossible to obtain an output voltage more than a voltage obtained by the voltage doubler rectification.

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