AU2002216436B2

AU2002216436B2 - Controller for a inrush current of air-conditioner compressor and thereof controlling method

Info

Publication number: AU2002216436B2
Application number: AU2002216436A
Authority: AU
Inventors: Sung-Kyu Seo
Original assignee: Individual
Current assignee: Individual
Priority date: 2000-12-18
Filing date: 2001-12-13
Publication date: 2005-03-03
Anticipated expiration: 2021-12-13
Also published as: KR20020048510A; AU1643602A; WO2002050477A1; KR100372056B1

Description

WO 02/50477 PCT/KRO1/02154 CONTROLLER FOR A INRUSH CURRENT OF AIR-CONDITIONER COMPRESSOR AND THEREOF CONTROOLNG METHOD Technical Field The present invention relates to an apparatus and a method for controlling in-rush current of an air conditioner compressor and, more particularly, to a method, which sequentially controls a relay controlling current flowing through a main coil, a relay controlling condensers and a relay protecting a current limiting device and a reactor to thereby control in-rush current generated when the compressor is started, and a controller having a resistor module for protecting the constituent elements mounted on a circuit board from heat generated from the current limiting device, separately constructed.

Background Art With a large-capacity inductive load, generally, high current corresponding to tens of times the consumption current of the inductive load flows for several msec at the moment when the inductive load starts, to cause an excessive load to electric or electronic elements. Back surge voltage caused by this high in-rush current generates fusing phenomenon at a contact such as switch. It means the surge voltage causes elements mounted on a board to have a trouble.

To solve this problem, a magnetic switch 30 (or AC power relay) that is a contact control element has been conventionally employed as a contact for applying power from a power supply 40 to a compressor 10 including a starting coil 12 to which a starting condenser is connected and a main coil 11. However, this element endures an obstacle due to the in-rush current at most but it does not have a function controlling the in-rush current.

The applicant proposed a technique of controlling the in-rush current using a O compressor 50 having a relay 92 connected in parallel with a starting coil 52 to which a ',starting condenser 60 is coupled and a main coil 51 to which a current limiting device is connected, as shown in FIG. 2. However, this controller does not fully function in a 00 N large-capacity co, pressor.

D 5 Accordi, engineers in the art have explored ways to solve the above-described problems. For instance, they proposed a method of using a cement (ceramic) resistor together with the current limiting device or a method of employing a heat sensor as the Scurrent limiting device. However, these techniques also did not control the in-rush current in case of an inductive air conditioner with large capacity of above That is, in the prior art, the magnitude of in-rush current generated when the air conditioner compressor is started becomes large in proportion to the capacity of the air conditioner, and resistance characteristic and heat caused by the increased in-rush current damage the resistor element, losing capability of controlling the in-rush current.

Disclosure of Invention The present invention provides 'an apparatus and a method for controlling in-rush current generated when an air conditioner compressor is started, the method sequentially controlling a relay controlling current flowing to a main coil, a relay controlling condensers and a relay for protecting a current limiting device and a reactor to thereby satisfactorily control the in-rush current even in a large-capacity air conditioner with high output power, the apparatus having a separate resistor module for protecting the constituent elements mounted on a circuit board from heat generated from the current limiting device.

In an aspect of the invention the main coil of the compressor having the main coil and a starting coil is serially connected to a WO 02/50477 PCT/KR01/02154 3 relay to which the current limiting device and the reactor constructing a resistor and a relay for protecting the current limiting device and the reactor are serially connected. In addition, the current limiting device and the reactor constructing the resistor are connected in parallel with the relay, and the starting coil is serially connected to an operation condenser, a starting condenser and a relay for controlling the starting condenser. The starting condenser and the relay are connected in parallel with the operation condenser.

The above-described relays are connected to a sequential control circuit to be controlled thereby.

In another aspect of the invention, to control the contact of the main coil, the main coil is serially connected to a triac to which the current limiting device and the reactor constructing the resistor and the relay for protecting the current limiting device and the reactor are serially connected. In addition, the relay for protecting the current limiting device and the reactor constructing the resistor is connected in parallel with the triac, the current limiting device and the reactor. Furthermore, To control the contact of the starting coil, a triac is serially connected to the starting coil, and this triac and the starting condenser are serially connected to each other.

In another aspect of the invention, to control the contact of the main coil, the triac connected to the main coil is serially connected to the current limiting device and a cement resistor constructing a resistor, the current limiting device and the cement resistor being connected in parallel with a relay for protecting them.

It is preferable that the current limiting device and the reactor forming the resistor are constructed in a module separated from the circuit board, and the current limiting device and the cement resistor are also constructed in a module separated from the circuit board.

The resistance of the current limiting device is half to five times the impedance 4 value of the reactor or cement resistor. The resistance of the current limiting device is 5-202 and the impedance of the reactor or cement resistor is 1-15Q when the load output oo power of the compressor is 2.0Kw. The resistance of the current limiting device is 2-40i and the impedance of the reactor or cement resistor is 1 -109 when the load output power ND 5 of the compressor is 3.0Kw. Furthermore, the resistance of the current limiting device is D 1-30Q and the impedance of the reactor or cement resistor is 0-792 when the load output Ci power of the compressor is In a further aspect of the present invention, there is provided a method for controlling in-rush current of an air conditioner compressor, the method reducing the inrush current generated in the air conditioner compressor using a controller which includes a compressor having a main coil and a starting coil and is constructed in a manner that relays are controlled by a sequential control circuit, the method comprising: a step in which, when power is applied to the air conditioner, a relay placed in close proximity to the main coil and serially connected thereto is not being in the contact state, and a relay serially connected to a starting condenser is in the contact state, to allow current to flow only to the starting coil of the compressor to thereby flow through both of an operation condenser and the starting condenser; a step in which, when the starting condenser and the operation condenser are charged with current so that resonance of the starting condenser and the operation condenser with the starting coil reaches to the maximum, contact of a relay, placed in close proximity to the main coil and serially connected to a current limiting device and a reactor, is made by the sequential control circuit to allow current to flow through the current limiting device and the reactor, to thereby normally start the compressor; and a step in which, when the compressor has completely started, the sequential control circuit breaks the contact of the relay serially connected to the starting condenser to allow current flows only through the operation condenser and, WO 02/50477 PCT/KR01/02154 simultaneously, the sequential control circuit makes a relay, connected in parallel with the current limiting device and the reactor, be in contact state to normally start the compressor, to thereby sequentially control the direction and quantity of current flowing through the compressor.

The control method of the invention may be constructed of: a step in which, when power is applied to the air conditioner, the relay placed in close proximity to the main coil and serially connected thereto is not being in the contact state, and a triac serially connected to the starting condenser is in the contact state, to allow current to flow only to the starting coil of the compressor to thereby flow through both of an operation condenser and the starting condenser; a step in which, when the starting condenser and the operation condenser are charged with current so that resonance of the starting condenser and the operation condenser with the starting coil reaches to the maximum, contact of a triac, serially connected to the current limiting device and the reactor, is made by the sequential control circuit to allow current to flow through the current limiting device and the reactor, to thereby normally start the compressor; and a step in which, when the compressor has completely started, the sequential control circuit breaks the contact of the triac serially connected to the starting condenser to allow current flows only through the operation condenser and, simultaneously, the sequential control circuit makes the relay, connected in parallel with the current limiting device and the reactor, be in contact state to normally start the compressor, to thereby sequentially control the direction and quantity of current flowing through the compressor.

The resistance of the current limiting device is half to five times the impedance value of the reactor or cement resistor. The resistance of the current limiting device is 5-20f and the impedance of the reactor or cement resistor is 1-15M when the load output power of the compressor is 2.0Kw. The resistance of the current limiting device is 2-400 and the impedance of the reactor or cement resistor is 1-10OD when the load output power F of the compressor is 3.0Kw. Furthermore, the resistance of the current limiting device is oo 1-30n and the impedance of the reactor or cement resistor is 0-7n when the load output power of the compressor is O Brief Description of the Drawings C, Further advantages of the invention can be more fully understood from r the following detailed description taken in conjunction with the accompanying drawings, in which: FIG. 1 shows a conventional circuit for driving an air conditioner compressor; FIG. 2 shows a conventional circuit for controlling in-rush current of an air conditioner compressor using a sequentially control circuit; FIG. 3a shows the configuration of a controller for controlling an air conditioner compressor according to an embodiment of the present invention; FIG. 3b shows the configuration of a controller for controlling an air conditioner compressor according to another embodiment of the present invention; FIG. 3c shows the configuration of a controller for controlling an air conditioner compressor according to another embodiment of the present invention; FIG. 3d shows the configuration of a controller for controlling an air conditioner compressor according to another embodiment of the present invention; FIG. 4 is a detailed circuit diagram of the controller shows in FIG. 3a; FIG. 5 shows the configuration of the controller for controlling in-rush current, in which a current limiting device and a relay construct a separate module, according to the present invention; FIG. 6 is a graph showing current characteristic obtained when a conventional air WO 02/50477 PCT/KR01/02154 7 conditioner compressor having a general controller starts; FIG 7 is a graph showing current characteristic obtained when a conventional air conditioner compressor having a controller using a current limiting device starts; FIG. 8 is a graph showing current characteristic obtained when a conventional air conditioner compressor having a controller using a current limiting device and a cement (ceramic) resistor starts; and FIG. 9 is a graph showing current characteristic obtained when an air compressor having a controller using a current limiting device and a reactor according to the invention starts.

Best mode for Carrying Out the Invention Preferred embodiments of the present invention are described below with reference to the attached drawings.

FIGS. 3a to 3d illustrate the different configurations of controllers for controlling in-rush current of an air conditioner compressor according to the present invention.

Though a circuit for controlling the in-rush current and a current limiting device 410 and a relay 420 constructing a resistor are shown together in FIGS. 3a to 3d, the current limiting device 410 and the relay 420 form a module separated from a circuit board 600 as shown in FIG. Because the current limiting device 410 is a heating resistor, it generates heat when current flows through it and the generated heat increases as the capacity of the device 410 becomes large, to affect the circuit of the controller, deteriorating the performance thereof.

Accordingly, the current limiting device 410 and the relay 420 are realized in a separate module.

It is preferable that the resistance of the current limiting device 410 is set to half to WO 02/50477 PCT/KR01/02154 8 five times the impedance of the reactor 420. The resistance of the current limiting device 410 and the impedance of the reactor 420 with respect to the output power of the air conditioner compressor 100 are shown in the following table. These resistance and impedance are experimental values and they are not limited to the following values.

Table 1 Load output power Resistance of current limiting device Impedance of reactor 5 to 20M 1 to 150 2 to 402 1 to 1 to 30n 0 to 792 The current limiting device 410 being covered with a heat-radiating case 700, as shown in FIG. 5, and the reactor 420, which barely generates heat because its pure resistance is close to 0, are arranged in series so that the current limiting device 410 can be rapidly recovered to the normal temperature and perform stabilized current control function.

The controller shown in FIG. 3a according to the present invention is constructed in such a manner that a relay 21 Oa for controlling current that flows along a main coil 11Oa of a compressor is connected to the main coil, and the current limiting device 410a and the reactor 420a forming a resistor and a relay 220a for protecting the current limiting device 410a and the reactor 420a are serially connected to the relay 210a. The current limiting device 410a and the reactor 420a are connected in parallel with the relay 220a.

A starting coil 120a of the compressor 100a is serially connected with an operation condenser 310a, a starting condenser 320a and a relay 230a for controlling the starting condenser 320a. The starting condenser 320a and relay 230a are connected in parallel with the operation condenser 310a. The relays 210a, 220a and 230a are connected to a sequential control circuit 500a to be controlled by the circuit 500a.

WO 02/50477 PCT/KR01/02154 9 The controller shown in FIG. 3b is constructed in such a manner that a main coil 110lb is serially connected to a relay 220b and resistor (current limiting device 410b and reactor 420b) which are connected in parallel with each other, and a relay 210b for controlling the main coil 1 10b is serially connected to the main coil. A starting coil 120b is connected to a starting coil 320b and an operation condenser 310b that is connected in parallel with a relay 230b. The relays 210b, 220b and 230b are controlled by a sequential control circuit 500b. That is, the controller shown in FIG. 3b performs the same function as that of the controller shown in FIG. 3a though the relays 210b and 230b change their positions.

FIGS. 3c and 3d show controllers configured using a triac according to another embodiment of the present invention.

The controller shown in FIG. 3c is constructed, as the controller of FIG. 1, in such a manner that a triac 210c is serially connected to a main coil 110c of a compressor l00c in order to control current flowing along the main coil, a current limiting device 410c and a reactor 420c forming a resistor are serially connected to the triac 210c, and a relay 220c for protecting the current limiting device 410c and reactor 420c is connected in parallel with the triac 210c, current limiting device 410c and reactor 420c. A starting coil 120c of the compressor 100c is serially connected to an operation condenser 310c, a starting condenser 320c and a triac 230c for controlling the operation condenser 320c. The starting condenser 320c and triac 230c are connected in parallel with the operation condenser 310c.

In addition, the triacs 210c and 230c and the relay 220a are connected to a sequential control circuit 500c to be controlled by the circuit 500c.

FIG. 3d illustrates that the reactor 420c shown in FIG. 3c is replaced with a cement resistor 420d. That is, the controller of FIG. 3d has the same configuration as that of the controller shown in FIG. 3c except that the cement resistor 420d is used as a resistor.

WO 02/50477 PCT/KR01/02154 Furthermore, the controllers shown in FIGS. 3c and 3d can be constructed, as the controller of FIG. 3a, in a manner that the relays 220c and 220d are connected in parallel with the current limiting devices 410c and 410d, reactor 420c and cement resistor 420d, respectively. This is because the relay 220c or 220d can be connected to any terminal of the triac 210c or 210d since the contact of the relay is made after complete operation of the compressor 100c or 100d has started. However, the triacs 210c and 210d are required to be protected because they are semiconductor contact devices. Accordingly, it is preferable that the triacs 210c and 210d are connected in parallel with the relays 220c and 220d, respectively.

In the embodiment using the triac, the controller can be designed in smaller size and the cost can be reduced because the triac, that is a semiconductor contact device, is much smaller than the relay. Furthermore, the triac can control the in-rush current more smoothly because it has the zero cross function of removing the generation of in-rush current from the beginning and a function of dividing and controlling input waveforms, in addition to the function of the reactor.

A method of controlling the in-rush current, generated when the air conditioner starts to operate, through the aforementioned configuration is carried out as follows. The method described blow controls the in-rush current using the controller shown in FIG. 3a.

Explanation for control methods using the controllers shown in FIGS 3b, 3c and 3d are omitted because the controllers of FIGS. 3b, 3c and 3d have the same configuration as that of the controller shown in FIG. 3a.

First of all, when power is applied to the compressor 100a, current caused by the power flows along the starting coil 120a of the compressor 100a. At this time, the relay 230a for controlling the current flowing through the starting condenser 320a is in contact state to allow the current to flow through both of the operation condenser 310a and WO 02/50477 PCT/KR01/02154 11 starting condenser 320a. It is preferable that the operation condenser 310a has the capacity of 30VLF to 60jF and the starting condenser has the capacity of 30[iF to 200tF according to the capacity of the air conditioner.

In the aforementioned embodiment, the load output power was 3.8Kw and the current that flows through the starting coil 120a when the compressor is initially operated was 30A approximately.

The starting condenser 320a and the operation condenser 310a are charged with the current flowing therethrough so that resonance of the condensers 310a and 320a with the starting coil 120a reaches the maximum, to allow a sufficient amount of current (20 to 30A approximately) required for starting the air conditioner to flow through the starting coil 120a. At this time, the sequential control circuit 500a sends a signal to the relay 210a serially connected to the main coil ll0a, and current flows through the main coil ll0a, current limiting device 410a and reactor 420a according to the operation of the relay 210a.

That is, the compressor 100a starts normally.

Here, the relay 220a connected in parallel with the current limiting device 410a and reactor 420a is not being in contact state. In addition, the in-rush current generated at this time corresponds to most of the entire in-rush current of the compressor 100a. That is, the starting coil 120a is charged with electricity in advance to reduce current through the condensers 310a and 320a and then decreases the current again through the current limiting device 410a and the reactor 420a so that the entire instantaneous in-rush current generated in the compressor 100a becomes below 5% of the value the compressor 100a has.

When the compressor 100a has completely started through the above-described procedure, the sequential control circuit 500a controls the relay 230a controlling the starting condenser 320a to block the current flowing to the starting condenser 320a so that WO 02/50477 PCT/KR01/02154 12 the compressor 100a can be normally operated only with the operation condenser 310a. In addition, the sequential control circuit 500a breaks the contact of the relay 230a and, simultaneously, allows the relay 22a connected in parallel with the current limiting device 410a and the reactor 420a to be in contact state. This is for the purpose of distributing current to solve the problem that the current limiting device 410a having heat-generating characteristic may be damaged when a large quantity of current flows through the current limiting device 410a and reactor 420a or it is not recovered to the normal temperature to perform the fUnction thereof in case where the air conditioner is stopped and then starts again.

FIGS. 6 to 9 show the magnitudes of in-rush current generated when the output power load of 3.8Kw is started using the conventional circuits and the control method and controller according to the present invention, which are outputted through the oscilloscope.

These results are obtained through experiments carried out in the same environment, that is, in the same place with the same output power.

Referring to FIG. 6, the magnitude of current is maximum 159.56A when a general air conditioner compressor starts. Through this graph, it can be known that considerably excessive instantaneous in-rush current is generated at the moment when a magnetic switch operates.

FIG 7 shows the in-rush current generated when an air conditioner compressor having the current limiting device starts. The in-rush current has the magnitude of 116.52A. FIG. 8 illustrates the in-rush current generated when an air conditioner compressor having the current limiting device and the cement resistor starts, which is 99.32A.

FIG. 9 shows the in-rush current generated when an air conditioner compressor is started with the controller using the in-rush current control method according to the WO 02/50477 PCT/KR01/02154 13 present invention. In this case, the in-rush current is generated at the moment the compressor is normally started, that is, the relay 210 connected to the main coil starts to operate. The generated in-rush current is 50.39A.

Through the aforementioned experiments, it can be known that the in-rush current can be controlled through the method of the invention though it is difficult to control using the conventional method because the magnitude of in-rush current increases as the output power becomes large. Specifically, the conventional air conditioner compressor (with output power of 2Kw or more) generates the instantaneous in-rush current of 60A to 150A, approximately, whereas the compressor according to the invention generates the in-rush current remarkably reduced to 20A to Industrial applicability As described above, according to the method and apparatus for controlling the inrush current of the air conditioner compressor of the present invention, the in-rush current mostly generated from the main coil is distributed to the starting coil at the initial stage to reduce the total starting current of the compressor and, even if current flows to the main coil again, over-current is absorbed by the current limiting device and the reactor.

Accordingly, the entire in-rush current of the compressor is remarkably decreased.

Furthermore, the current limiting device and the reactor constructing the resistor at the main coil side are configured in a separated module so that heat generated in the current limiting device is rapidly recovered to the normal temperature to results in stabilized operation of the current limiting device.

Although specific embodiments including the preferred embodiment have been illustrated and described, it will be obvious to those skilled in the art that various modifications may be made without departing from the spirit and scope of WO 02/50477 PCT/KRO1/02154 the present invention, which is intended to be limited solely by the appended claims.

Claims

1. A controller for controlling in-rush current of an air conditioner compressor, which has a compressor having a main coil and a starting coil and reduces the in-rush current generated in the air conditioner compressor using a circuit constructed in a manner that relays are controlled by a sequential control circuit, wherein the main coil is serially connected to a relay to which a current limiting device and a reactor constructing a resistor are serially connected, the current limiting device and the reactor constructing the resistor being connected in parallel with a relay for protecting them; an operation condenser, a starting condenser and a relay for controlling the starting condenser are serially connected to the starting coil, the starting condenser and the relay for controlling the starting condenser being connected in parallel with the operation condenser; and the relays are connected to the sequential control circuit to be controlled thereby.

2. The controller as claimed in claim 1, wherein the main coil is serially connected to a triac to which the current limiting device and the reactor WO 02/50477 PCT/KR01/02154 16 constructing the resistor are serially connected, the current limiting device and the reactor constructing the resistor being connected in parallel with the relay for protecting them; the operation condenser, the starting condenser and a triac for controlling the starting condenser are serially connected to the starting coil, the starting condenser and the triac for controlling the starting condenser being connected in parallel with the operation condenser; and the triacs and the relays are connected to the sequential control circuit to be controlled thereby

3. The controller as claimed in claim 2, wherein the main coil is serially connected to the triac to which the current limiting device and a cement resistor constructing the resistor are serially connected, the current limiting device and the cement resistor constructing the resistor being connected in parallel with a relay for protecting them;

4. The controller as claimed in claim 1 or 2, wherein the current limiting device and the reactor are constructed in a module separated from a circuit board. WO 02/50477 PCT/KR01/02154 17 The controller as claimed in claim 3, wherein the current limiting device and the cement resistor are constructed in a module separated from the circuit board.

6. The controller as claimed in one of claimsl, 2 and 3, wherein the resistance of the current limiting device is half to five times the impedance value of the reactor or cement resistor.

7. The controller as claimed in one of claims 1, 2 and 3, wherein the resistance of the current limiting device is 5-200 and the impedance of the reactor or cement resistor is 1-150 when the load output power of the compressor is

8. The controller as claimed in one of claims 1, 2 and 3, wherein the resistance of the current limiting device is 2-40Q and the impedance of the reactor or cement resistor is 1-10( when the load output power of the compressor is

9. The controller as claimed in one of claims 1, 2 and 3, wherein the resistance of the current limiting device is 1-30M and the impedance of the reactor WO 02/50477 PCT/KR01/02154 18 or cement resistor is 0-7K2 when the load output power of the compressor is 4.OKw. A method for controlling in-rush current of an air conditioner compressor, the method reducing the in-rush current generated in the air conditioner compressor using a controller which includes a compressor having a main coil and a starting coil and is constructed in a manner that relays are controlled by a sequential control circuit, the method comprising: a step in which, when power is applied to the air conditioner, a relay placed in close proximity to the main coil and serially connected thereto is not being in the contact state, and a relay serially connected to a starting condenser is in the contact state, to allow current to flow only to the starting coil of the compressor to thereby flow through both of an operation condenser and the starting condenser; a step in which, when the starting condenser and the operation condenser are charged with current so that resonance of the starting condenser and the operation condenser with the starting coil reaches to the maximum, contact of a relay, placed in close proximity to the main coil and serially connected to a current limiting device and a reactor, is made by the sequential control circuit to allow current to flow through the current limiting device and the reactor, to thereby normally start the compressor; and WO 02/50477 PCT/KR01/02154 19 a step in which, when the compressor has completely started, the sequential control circuit breaks the contact of the relay serially connected to the starting condenser to allow current flows only through the operation condenser and, simultaneously, the sequential control circuit makes a relay, connected in parallel with the current limiting device and the reactor, be in contact state to normally start the compressor, to thereby sequentially control the direction and quantity of current flowing through the compressor.

11. The method as claimed in claim 10, comprising: a step in which, when power is applied to the air conditioner, the relay placed in close proximity to the main coil and serially connected thereto is not being in the contact state, and a triac serially connected to the starting condenser is in the contact state, to allow current to flow only to the starting coil of the compressor to thereby flow through both of an operation condenser and the starting condenser; a step in which, when the starting condenser and the operation condenser are charged with current so that resonance of the starting condenser and the operation condenser with the starting coil reaches to the maximum, contact of a triac, serially connected to the current limiting device and the reactor, is made by the sequential control circuit to allow current to flow through the current limiting device WO 02/50477 PCT/KR01/02154 and the reactor, to thereby normally start the compressor; and a step in which, when the compressor has completely started, the sequential control circuit breaks the contact of the triac serially connected to the starting condenser to allow current flows only through the operation condenser and, simultaneously, the sequential control circuit makes the relay, connected in parallel with the current limiting device and the reactor, be in contact state to normally start the compressor, to thereby sequentially control the direction and quantity of current flowing through the compressor.

12. The method as claimed in claim 10 or 11, wherein the resistance of the current limiting device is half to five times the impedance value of the reactor or cement resistor.

13. The controller as claimed in claim 10 or 11, wherein the resistance of the current limiting device is 5-20) and the impedance of the reactor or cement resistor is 1-15Q when the load output power of the compressor is

14. The controller as claimed in claim 10 or 11, wherein the resistance of the current limiting device is 2-40.2 and the impedance of the reactor or cement resistor is 1-100 when the load output power of the compressor is The controller as claimed in claim 10 or 11, wherein the resistance of the current limiting device is 1-300 and the impedance of the reactor or cement resistor is 0-70 when the load output power of the compressor is

16. A controller for controlling in-rush current of an air conditioner compressor substantially as hereinbefore described with reference to accompany drawings 3 to 9.

17. A method for controlling in-rush current of an air conditioner compressor having the steps substantially as hereinbefore described Dated 27 January 2005 Freehills Patent Trade Mark Attorneys Patent Attorneys for the Applicant/s: Yoon Sik CHOI