JP2001268920A - Active filter and dc appliance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low-noise active filter having simple configuration, and an economical and highly-efficient DC appliance using the active filter. SOLUTION: This active filter is provided with at least one reactor and one switching element connected in series for a commercial power supply input to obtain boosted output for the input through a diode from ends of the switching element. The reactor is disposed with an inductance component at least on both of the input.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a configuration of an active filter and a configuration of a low-noise DC device for improving a power factor required for a DC device using a commercial power supply as an input.

[0002]

2. Description of the Related Art In recent years, it is well known that energy saving and cost reduction are the most important propositions in electronic devices. In DC machines such as inverter air conditioners that consume a large amount of power, improvement of power factor and improvement of power conversion efficiency have been known. Improvement is an indispensable proposition in terms of social constraints.

Accordingly, in order to cope with the above-mentioned proposition, conventionally, as shown in FIG. 5A, a commercial power supply input is first passed through a full-wave rectifier circuit of diodes D51 to D54 to connect a reactor L51 and a switch element Q51. An active filter type DC device which improves the power factor to a value close to 1 by an active filter configuration which is provided in series and obtains a DC output boosted with respect to the input via a diode D55 in accordance with the switching operation of the switching element Q51. The configuration has been taken.

[0004]

However, when a DC device is actually constructed using the above-described conventional active filter, as shown in FIG. 5B, the switching noise of the switching element Q51 and the diode Due to the occurrence of the recovery noise of D55, the noise terminal voltage level fed back to the commercial input exceeds the official standard to be observed in the equipment, as shown in FIG. There was an obstacle that would be.

In other words, since the operation of the reactor and the switching element with respect to the input is in an unbalanced mode until the operation reaches a transient state, the path of the generated noise returns to the input because the noise path is strong in addition to the common mode noise with respect to the ground. What
In addition, since a normal mode noise component is superimposed, it is indispensable to configure a large-scale noise filter on the input side, and even in such a case, the noise terminal voltage level is further increased to satisfy official standards. However, there is a serious disadvantage that the economical efficiency of the equipment is greatly reduced.

In addition, in the above-described conventional configuration, since the level of the diode D55 is added to the forward voltage loss required for full-wave rectification during the step-up power conversion, the efficiency is reduced by that amount. There were also disadvantages.

An object of the present invention is to provide a low-noise active filter having a simple configuration and an economical and highly efficient DC device using the active filter.

[0008]

According to the present invention, at least one or more reactors and a switch element are provided in series with respect to a commercial power supply input, and a voltage is boosted from both ends of the switch element via a diode to the input. An active filter for obtaining an output, wherein the reactor is provided with an inductance component in at least both of the input lines.

Further, the present invention is the above-described active filter, wherein the inductance component provided on both of the input lines is formed by applying a plurality of windings to one magnetic core.

[0010] Further, the present invention is characterized in that an inductance component is interposed between a ground terminal of a commercial input outlet connected to the active filter and a frame provided in the active filter. It is.

Further, the present invention is a DC device comprising the above active filter.

That is, at least 1
In one or more reactors and a switch element provided in series, an active filter that obtains an output boosted with respect to the input via a diode from both ends of the switch element, and a DC device including the active filter,
The reactor is provided with an inductance component on at least both of the input lines, and the inductance component provided on both of the input lines is formed by applying a plurality of windings to one magnetic core. And a DC device including the active filter.

[0013] In addition, an active filter characterized in that an inductance component is interposed between a ground terminal of a commercial input outlet connected to the active filter and a frame provided in the active filter, and the active filter. It is a direct current equipment device provided with.

According to the above-described active filter and the DC device using the active filter according to the present invention, the operation of the reactor and the switching element with respect to the input is performed by:
Until the transient state, the components operate on the balanced mode by the reactor components attached to both lines.Therefore, the path for the generated noise to return to the input is dominated by only the common mode noise component with respect to the ground. Since a strong normal mode noise component such as technology is not superimposed, it is possible to satisfy the official standard of the noise terminal voltage level only by configuring an extremely small noise filter on the input side, and realize high equipment economy. can do.

Furthermore, if the reactors mounted on both lines are mounted on the commercial AC input line, the element corresponding to the diode D55 described in the above-mentioned problem of the prior art becomes unnecessary, and the order required for full-wave rectification is eliminated. Since the function can be performed only by the directional voltage loss, the advantage that the decrease in the efficiency can be suppressed correspondingly is also obtained.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of an active filter according to the present invention and a DC apparatus using the active filter will be described below in detail with reference to the drawings.

FIG. 1 is a view showing an embodiment of an active filter according to the present invention. At least one or more reactors and a switch element are provided in series with respect to a commercial power supply input, and a diode is provided from both ends of the switch element. Is an active filter that obtains an output boosted with respect to the input through the input.

First, in FIG. 1A,
Reactors mounted on both lines are separate reactors L1
FIG. 2 is a diagram showing a first embodiment of the active filter according to claim 1 when L2 and L13 are set.

FIG. 1 (b) shows an active filter according to claim 2, wherein two windings are formed on one magnetic core, and a reactor is formed so as to have an inductance component of a phase opposite to each other, and the reactor is disposed on both input lines. It is a figure showing an embodiment.

FIG. 1C shows a second embodiment of the active filter according to claim 1, wherein the same reactor as that shown in FIG. 1B is provided on both lines after the input line is full-wave rectified. FIG. 8 is a diagram showing a second embodiment.

FIGS. 2 (a), 1 (b) and 1
Fig. 4 illustrates the outline of operation of the active filter configuration according to the present invention described in (c). When two switch elements are used, the positive and negative half cycles of the commercial AC input are shared, and when one switch element is used, both are shared.
As shown in FIG. 2 (a), the relationship between the reactor mounted on both lines and the reactor and the input / output is that while the switch element is on, energy is applied to the magnetic core while sharing the input voltage Vin with both inductance components by half. During the period of charging and off, as shown in FIG. 2B, the output voltage Vo and the input voltage Vin
While discharging the energy from the magnetic core while sharing the difference between the two by the two inductance components, the boost converter operation is continued. In order to make the output voltage Vo desired, as is well known, the control circuit cont11 shown in FIG.
By adjusting the on-duty of the switching element by comparing the internal reference voltage with the output voltage Vo.

As shown in FIGS. 1 (a) and 1 (b), when the reactors mounted on both lines are mounted on the commercial AC input line, the diode D55 described in the problem of the prior art described above can be used. Since a corresponding element is not required, and it can function only with forward voltage loss required for full-wave rectification, a decrease in efficiency can be suppressed by that much, and a highly efficient active filter can be obtained.

FIG. 3 is a diagram showing an embodiment of the present invention described in claims 3 and 4 for putting a DC device using an active filter according to the present invention into practical use.

As described above, the active filter according to the present invention operates in a balanced mode until the operation of the reactor and the switching element for commercial input reaches a transient state due to the reactor components mounted on both lines.

Therefore, as for the path on which the generated noise returns to the input, the noise path is dominated by only the common mode noise component with respect to the ground, and the strong normal mode noise component as described in the prior art is not superimposed. By simply configuring a very small noise filter on the input side, it is possible to satisfy the official standard of the noise terminal voltage level, and to realize high economic efficiency of equipment.

However, as shown in FIG. 2C, the reference level of the output voltage of the present active filter is Vin / 2,
And (Vo-Vin) / 2 between the ground, the load range for the output is wide, and if there is a large stray capacitor between the ground and the ground, the ground terminal of the input outlet and the middle point of the noise filter The configuration is such that a path in which the common mode noise level increases is interposed by interposing a reactor (inductance component) L34.

FIG. 4A is a diagram showing an embodiment of the present invention applied to an inverter air conditioner as a DC device using an active filter according to the third and fourth aspects.

In this case, not only is the area on the load side connected to the output large, but also the refrigerant pipes between the indoor units with the compressor housed in the outdoor unit shown in FIG. In addition, since the path of the common mode noise component via the large stray capacitance increases,
A reactor (inductance component) L44 is interposed between the ground terminal of the input outlet and the midpoint of the line bypass capacitor of the noise filter to cut off the path where the common mode noise level increases, as shown in FIG. This realizes an inverter air conditioner as a low-noise DC device with a simple configuration.

[0029]

As described above, according to the present invention, it is possible to provide a low-noise active filter with a simple configuration, and an economical and highly efficient DC device using the active filter.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an active filter of the present invention.
FIG. 1A is a diagram showing a first embodiment corresponding to claim 1. FIG. 1B is a diagram showing an embodiment corresponding to claim 2. FIG. 1C is a diagram showing a second embodiment corresponding to claim 1.

FIG. 2 is a diagram showing an operation model of an active filter according to the present invention. FIG. 2A is a diagram illustrating an equivalent model when a switch element is turned on. FIG. 2B is a diagram illustrating an equivalent model when the switch element is off. FIG. 2C is a diagram illustrating a Vdb (voltage between db) waveform.

FIG. 3 is a diagram showing an active filter and a DC device according to claims 3 and 4 of the present invention.

FIG. 4 is a diagram showing an example in which the active filter according to claims 3 and 4 is applied to an inverter air conditioner. FIG. 4 (a)
1 is a diagram showing an embodiment of an inverter air conditioner. FIG.
(B) is a diagram showing noise levels of the present invention and a conventional inverter air conditioner.

FIG. 5 is a diagram showing a conventional active filter and a DC device. FIG. 5A shows a conventional active filter. FIG. 5B is a diagram illustrating a conventional DC device.

[Explanation of symbols]

D11, D12, D13, D14, D15 Diode D31, D32, D33, D34 Diode D51, D52, D53, D54, D55 Diode L11, L12, L13 Reactor L31, L34, L35 Reactor L51, L55, L56 Reactor Q11, Q12, Q13 Switching element Q51 Switching element CONT11, CONT12 Control circuit CONT31 Control circuit CONT51 Control circuit

Claims (4)

[Claims] 1. An active filter for providing at least one or more reactors and a switching element in series with respect to a commercial power supply input, and obtaining an output boosted from the input via a diode from both ends of the switching element.
An active filter, wherein the reactor is provided with an inductance component at least on both of the input lines. 2. The active filter according to claim 1, wherein the inductance components provided on both of the input lines are formed by applying a plurality of windings to one magnetic core. 3. The active device according to claim 1, wherein an inductance component is interposed between a ground terminal of a commercial input outlet connected to the active filter and a frame included in the active filter. filter. 4. A DC device comprising the active filter according to claim 1.