GB2330462A

GB2330462A - Harmonic current attenuating apparatus of a motor

Info

Publication number: GB2330462A
Application number: GB9822072A
Authority: GB
Inventors: Bu-Hyeon Kim
Original assignee: Kwangju Electronics Co Ltd
Current assignee: Kwangju Electronics Co Ltd
Priority date: 1997-10-16
Filing date: 1998-10-12
Publication date: 1999-04-21
Anticipated expiration: 2018-10-12
Also published as: NL1010328C2; ITRM980645A1; JPH11196596A; FR2770051B1; IT1302373B1; CH689503A5; GB2330462B; SE9803523L; DE19847639A1; CN1215248A; GB9822072D0; CN1065374C; SE9803523D0; FR2770051A1; NL1010328A1; SE519789C2

Abstract

A harmonic current attenuating apparatus of a motor 30 which controls a rotation speed of the motor 30 by phase-controlling a sine wave AC power supplied from a power supply unit 10 and attenuates the harmonic current generated at a phase-controlling mode of the AC power by way of an harmonic current attenuating unit wherein the apparatus comprises: a manipulating unit 34 for selecting a phase-controlling mode or a full power operation mode according to manipulation of a user; and a switching unit 21 for supplying the AC power supplied from the power supply unit 10 through the harmonic current attenuating unit 20 to the motor 30 when the phase-controlling mode is selected by the manipulating mode, and for supplying the AC power from the power supply unit 10 directly to the motor 30 when the full power operation mode is selected, such that there is an advantage in the harmonic current attenuating apparatus of a motor in that it effectively attenuates the harmonic current through a harmonic transformer 20 at the phase-controlling mode and substantially improves an output of the motor 30 by directly supplying the AC power from the power supply unit 10 to the motor 30 without phase-controlling at a full power operation mode. The unit 21 may be a triac (Figs 6 and 7). The motor may be used to drive a cleaner.

Description

2330462 HARMONIC CURRENT ATTENUATING APPARATUS OF A MOTOR The present

invention relates to a harmonic current attenuating apparatus of a motor which attenuates the harmonic current generated while a motor is driven, thereby to maximize the output of the motor.

A conventional motor driving circuit in a cleaner includes, as shown in figure 1, power supply means 10 for supplying an alternating current AC power source having a commercial frequency, filtering means 12 for filtering a noise of the AC power source supplied from the power supply means 10, a motor 30 driven by the AC power source supplied from the power supply means 10, phase control means 32 for phase-controlling the AC power source supplied from the power supply means 10 to the motor 30, a slide switch 34 for driving or not driving the motor 30 according to manipulation of a user and for controlling a rotary speed of the motor 30, and a TRIAC (TRIode AC switch) for being switched by control of the phase control means 32 to phase-control the AC power source supplied from the motor 30.

The phase control means 32 includes a condenser C, a resistor R and a DIAC (Diode AC switch), where the DIAC is turned on when a voltage supplied via the condenser C and the resistor R surpasses a predetermined voltage (preferably, approximately 40KV) to supply a current to a gate terminal of the TRIAC, and the TRIAC is switched by the operation of the DIAC such that the AC power source supplied from the power supply means 10 to the motor 30 is phase-controlled.

Furthermore, the slide switch 34 includes a switch SW, a choke coil L and a variable resistance VR. Contact points (a, b) of the switch SW are turned on and off by manipulation of a user, thereby supplying the power to the motor 30 by the power supply means 10 and controlling the speed of the motor 30 according to the slide volume value changed by the variable resistance VR. At this time, the choke coil L is used for filtering the high frequency generated when the slide volume value is changed.

operational procedures of the conventional cleaner are described in detail with reference to Figure 1. At f irst, the contact point (a, b) of the switch SW are rendered operative by manipulation of the slide switch 34 to supply the AC power to the phase control means 32 via the choke coil L and variable resistor VR. At this time, the filtering means 12 serves to filter the noise included in the AC power supplied to the motor 30.

Then, the DIAC at the phase control means 32 is turned on and off by the AC power filtered through the filtering means 12 such that the TRIAC is switched by the operation of the DIAC to thereby phase-control the AC power source supplied to the motor 80.

At this time, the motor 30 is driven by the AC power supplied from the power supply means 10 through the TRIAC. The internal air is forcibly circulated by an impeller which is rotated in cooperation with the motor 30 and then contaminants like dusts are sucked in from a suction opening by the wind generated by a pressure difference between an exterior and an interior of the cleaner, such that the cleaning is executed..

Here, waveforms of the voltage V and current I supplied to the motor 30 are shown in Figure 2. On the other hand, the TRIAC is switched by changing on or of f of the DIAC of the phase control means 32. The commercial frequency sinusoidal wave voltage supplied from the power supply means 10 is phase- controlled to change into a nonsinusoidal wave voltage to be supplied to the motor 30, whereby a harmonic frequency is generated.

As products such as a cleaner and the like are increased in supply thereof, the total amount of the harmonic current drawn to a power system is increased so much, causing an operating disorder to a power condenser, a brake and the like to result in breakdown of a transformer.

In order to prevent the disorder due to the harmonic current as described above, an International Electrotechnical Commission (IEC) established a standard of limiting the harmonic current. According to this standard, various harmonic currents are generated at a cleaner where the phase of the AC power supplied to a motor is controlled at 900 + 100, and what matters is a third harmonic current as shown in Figure 3.

Thus, it is an urgent problem to attenuate the third harmonic current to meet the standard of limiting the harmonic current. Researches have been made on the technique for attenuating the third harmonic current in various technical fields related to the cleaner.

A technique for attenuating the third harmonic current, as shown in Figure 4, was filed for patent registration on August 25, 1997 with the Korean Industrial Property office under the title of "harmonic current attenuating device of a motor According to the device, the AC power with commercial frequency supplied from the power supply means 10 is switched by the TRIAC and phase- controlled into a non-sinusoidal wave to be supplied to the motor 30. The harmonic current generated by phasecontrolling the AC power supplied to the motor 30 at phase of 900 + 100 is attenuated by a reactor 20 hereinafter referred to as a harmonic transformer, a kind of a resistance element, thereby effectively attenuating the third harmonic current.

However, there is a problem in the harmonic current attenuating device of a motor shown in Figure 4 in that, in case the AC power is supplied through a harmonic transformer to the motor for the purpose of attenuating the harmonic current generated at the phase-controlling mode of the motor, and even when the motor is driven at a full power operation mode without phase-controlling, the harmonic transformer operating as a resistance element causes a drop in voltage of AC power and limits an output of the motor at a predetermined value (for instance, about 140OW), thereby resulting in a weak suction force.

it is an aim of preferred embodiments of the present invention to solve or reduce the aforementioned problems and it is an aim to provide a harmonic current attenuating apparatus of a motor which effectively attenuates harmonic current through a harmonic transformer at the phasecontrolling mode and substantially improves an output of the motor by directly supplying the AC power from a power supply means to the motor without phase-controlling at a full power operation mode.

According to a first aspect of the present invention, there is provided a harmonic current attenuating apparatus of a motor which controls a rotation speed of the motor by phase-control ling a sine waved AC power supplied from a power supply means and attenuates the harmonic current generated at a phase-controlling mode of the AC power by way of harmonic current attenuating means, wherein the apparatus comprises:

manipulating means for selecting a phase-controlling mode or a full power operation mode according to manipulation of a user; and switching means for supplying the AC power supplied from the power supply means through the harmonic current attenuating means to the motor when the phase-controlling mode is selected by the manipulating mode, and for supplying the AC power output from the power supply means directly to the motor when the full power operation mode is selected.

The switching means may be a micro-switch by which the AC power supplied from the power supply means by way of switching according to a mode selected by the manipulating means is supplied to the motor via the harmonic current attenuating means or directly supplied to the motor without passing through the harmonic current attenuating means.

The switching means may alternatively comprise a TRIAC by which the AC power supplied from the power supply means by way of switching according to a mode selected by the manipulating means is supplied to the motor via the harmonic current attenuating means or directly supplied to the motor without passing through the harmonic current attenuating means.

The switching means may comprise: charge /discharge means for being charged or discharged by the AC power supplied from the power supply means when the full power operation mode is selected by the manipulating means; a DIAC for being turned on or off by a voltage supplied via the charge/discharge means; and a TRIAC for supplying the AC power supplied from the power supply means directly to the motor without passing the same through the harmonic current attenuating means when the DIAC is turned on.

For a better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example, to the accompanying diagrammatic drawings, in which:

Figure 1 is a diagram for illustrating a motor driving circuit in a general cleaner according to the prior art;

Figures 2 and 3 are diagrams for illustrating a harmonic current generated from a general motor of the prior art;

Figure 4 is a diagram for illustrating a motor driving circuit having a harmonic transformer for attenuating a harmonic current according to the prior art;

Figure 5 is a diagram for illustrating a harmonic current attenuating apparatus of a motor in accordance with a first embodiment of the present invention; Figure 6 is a diagram for illustrating a harmonic current attenuating apparatus of a motor in accordance with a second embodiment of the present invention; Figure 7 is a diagram for illustrating a harmonic current attenuating apparatus of a motor in accordance with a third embodiment of the present invention; and Figure 8 is a diagram for describing an output of the motor in accordance with the present invention.

Preferred embodiments of the present invention are described in detail with reference to the accompanying drawings, like reference numerals and symbols are used for designation of like or equivalent parts or portions for simplicity of illustration and explanation, and redundant references will be omitted.

As the harmonic current attenuating apparatus comparatively shown in Figures 5 and 6 and in Figure 4, each embodiment of the present invention includes: contact point (b) formed at a slide switch 34 corresponding to a full power operation mode of the motor; and switching means 21 for selectively supplying AC power supplied from the power supply means 10 via a harmonic transformer 20 to a motor 30 as contact points (a, b) are turned on or off corresponding to the full power operation mode at the slide switch 34 set by an operator.

Here, the switching means, as shown in the first embodiment of the present invention, is a micro-switch 22 to switch the contact points (h, i) when the contact points (a, b) at the slide switch 34 are changed on or off, whereby the AC power supplied from the power supply means 10 may be supplied through the harmonic transformer 20 to the motor 30 or directly to the motor 30.

Inaddition, the switching means 21 as second embodiment of the present invention, TRIAC2 24 when the contact points (a, b) switch 34 are changed on or off, whereby supplied from the power supply means 10 shown in the is a second at the slide the AC power is supplied - 8 through the harmonic transformer 20 to the motor 30 or directly to the motor 30.

Furthermore, the switching means 21 includes, as illustrated in Figure 7, charge/discharge means 24 having a condenser C2 and a resistor R2 for receiving the AC power from the power supply means 10 via contact points (a, b) in the slide switch 34 to thereafter charge or discharge, a second DIAC2 for turning on or off according to a voltage supplied via the charge/discharge means 24, a second TRIAC2 for directly supplying to the motor 30 the AC power supplied from the power supply means 10 when the second DIAC2 is activated, whereby the AC power supplied from the power supply means 10 is directly supplied to the motor 30 according as the contact points (a, b) in the slide switch 34 are closed or opened, or the AC power supplied from the power supply means 10 via the first TRIAC1 is supplied to the motor 30 via the harmonic transformer 20.

Hereinafter operational procedures of the harmonic current attenuating apparatus in accordance with the first embodiment of the present invention are described in detail with reference to Figures 5 and 8. The microswitch 22 is set off at its initial state.

First of all, if the contact points (c, f) are respectively connected to the contact point (a) of the switch SW by an operator's manipulation of the slide switch 34, the AC power supplied from the power supply means 10 is filtered by the filtering means 12 and supplied to the phase controlling means 32. At this time, the noise included in the AC is filtered through the filtering unit 12, and the DIAC of the phase controlling means 32 is rendered on or off the filtered AC, thereby switching the TRIAC for phase-controlling the AC power to be supplied to the motor.

Accordingly, the AC phase-controlled through the TRIAC passes through the harmonic transformer 20, thereby attenuating the harmonic current generated at the phasecontrolling mode to be supplied to the motor 30 to drive the motor 30.

Therefore, the internal air is forcibly circulated by an impeller which is rotated in cooperation with the motor 30 and then contaminants like dusts are sucked in from a suction opening by the wind generated by a pressure difference between an exterior and an interior of the cleaner.

At this time, as the contact points (c, f) of the switch SW are connected to the contact point (a), the speed of the motor 30 is controlled by the resistance value of the variable resistance VR according to user's manipulation.

On the other hand, when the contact points (b, e) are connected to the contact point (a) in the switch 34 (at t in Figure 8), the contact points (h, i) of the microswitch 22 are mutually connected.

Therefore, the AC power supplied through the TRIAC is directly sent through the micro-switch 22 without passing through the harmonic transformer 20. If the motor 30 is driven at the full power operation mode, a drop in voltage of the AC power is not caused by the harmonic transformer 20 functioning as a resistance element, thereby increasing an output of the motor 30 to more than 1,60OW, as shown in Figure 8.

Next, operational procedures of the harmonic current attenuating apparatus in accordance with the second embodiment of the present invention are described in detail with reference to Figures 6 and 8. The second 5 TRIAC2 is set off at its initial state.

First of all, when the contact points (c, f) of the switch SW are respectively contacted to the contact point (a) of the switch SW by an operator's manipulation of the slide switch 34, the AC power is supplied from the power supply means 10 to the motor 30. At this time, the noise included in the AC power is filtered through the filtering means 12, and the DIAC of the phase- controlling means 32 is turned on or off, thereby switching the first TRIAC1 for controlling the phase of the AC power to be supplied to the motor 30.

Accordingly, the AC power phase -control led through the first TRIAC passes through the harmonic transformer 20, thereby attenuating the harmonic current generated at the phase- control ling mode to be supplied to drive the motor 30.

At this time, as the contact points (c, f) are connected to the contact point (a) of the switch (SW) at the slide switch 34 the speed of the motor 30 is controlled by the resistance value of the variable resistance VR according to the user's manipulation.

on the other hand, when the contact points (b, e) are connected to the contact point (a) of the slide switch 34 (t in Figure 8) to operate the motor at the full power operation mode without controlling the phase of the motor 5 30, the second TRIAC2 is switch on.

Therefore, the AC power supplied through the first TRIAC1 is directly sent through the micro-switch 22 without passing through the harmonic transformer 20. if the motor 30 is driven at the full power operation mode, and drop in voltage of the AC power is not caused by the harmonic transformer 20 functioning as a resistance element, thereby increasing an output of the motor 30 to more than 1,60OW, as shown in Figure 8.

Now, the third embodiment of the present invention will be described in detail with reference to Figures 7 and 8. The second TRIAC 2 is set of f at its initial stage.

When the contact points (a, c) are connected to each other by manipulation of the slide switch 34 in order to control the phase of the AC power, the AC power supplied from the power supply means 10 is filtered by the filtering means 12, which is then supplied to the phase controlling means 32. Successively, the first DIAC1 is switched on or off, and the first TRIACI is then switched according to the operation of the first DIACI, such that the AC power supplied from the power supply means 10 is phase-controlled.

Furthermore, the AC power phase-controlled by the first TRIAC1 passes through the harmonic transformer 20, and the harmonic current generated during the phase controlling is attenuated to thereafter be supplied to the motor 30 and to drive the motor 30.

Successively, the internal air is forcibly circulated by an impeller which is rotated in cooperation with the motor 30 and then contaminants like dusts are sucked in from a suction opening by the wind generated by a pressure difference between an exterior and an interior of the cleaner.

At this time, the motor 30 is adjusted inspeed thereof by changes of resistance value of the variable resistance VR according to the manipulation of a user when the contact points (a, c) in the slide switch 34 are mutually connected.

In the meantime, when the contact points (a, b) in the slide switch 34 are connected to each other (t in Figure 8) to operate the motor 30 at the full power 20 operation mode without controlling the phase of the motor 30, the AC power is supplied to a gate terminal at the second TRIAC2 through the charge/ discharge means 24 and the second DIAC2 to thereby switch on the second TRIAC2.

Successively, the AC power supplied from the power supply means 10 is directly applied to the motor 30 without passing through the harmonic transformer 20. if the motor 30 is driven at the full power operation mode, the AC power is not dropped in voltage thereof to increase the output of the motor 30 to more than 1,60OW as shown in Figure 8.

At this time, an erroneous operation caused by external power noise of the second TRIAC2 is prevented because of use of the charge /discharge means 24 and the second DIAC2.

Particularly, in the case of a handle-controller cleaner with the slide switch 34 attached on a cleaner hose, there is a problem of erroneous operation at the second TRIAC2 due to severe external power noise. However, the charge /discharge means 24 and the second DIAC2 utilized thereon prevents the erroneous operation of the second TRIAC2.

As apparent from the foregoing, there is an advantage in the harmonic current attenuating apparatus of a motor in that it effectively attenuates harmonic current through the harmonic transformer at the phase-control ling mode and substantially improves an output of the motor by directly supplying the AC power from the power supply means to the motor without phase-controlling at a full power operation mode.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

- 14 Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

- is -

Claims

1. A harmonic current attenuating apparatus of a motor which controls a rotation speed of the motor by phasecontrolling a sine waved AC power supplied from a power supply means and attenuates the harmonic current generated at a phas e-control ling mode of the AC power by way of harmonic current attenuating means, wherein the apparatus comprises:

2. The apparatus as defined in claim 1, wherein the switching means is a micro-switch by which the AC power supplied from the power supply means by way of switching according to a mode selected by the manipulating means is supplied to the motor via the harmonic current attenuating means or directly supplied to the motor without passing through the harmonic current attenuating means.

3. The apparatus as defined in claim 1, wherein the switching means is a TRIAC by which the AC power supplied from the power supply means by way of switching according to a mode selected by the manipulating means is supplied to the motor via the harmonic current attenuating means or 16 directly supplied to the motor without passing through the harmonic current attenuating means.

4. The apparatus as defined in claim 1, wherein the switching means comprises:

charge/discharge means for being charged or discharged by the AC power supplied from the power supply means when the full power operation mode is selected by the manipulating means; a DIAC for being turned on or off by a voltage supplied via the charge/discharge means; and a TRIAC for supplying the AC power supplied from the power supply means directly to the motor without passing the same through the harmonic current attenuating means when the DIAC is turned on.

5. A harmonic current attenuating apparatus substantially as herein described with reference to Figure 8 in conjunction with Figure 5, 6 or 7.