Impedance matching method and impedance matching system
An impedance matching device and an impedance matching method. A variable reactance impedance matching network is disposed between a variable frequency RF power source varying a driving frequency and a load. An impedance matching method of the variable reactance impedance matching network includes controlling variation amount of capacitance or reactance of a variable reactive component of the impedance matching network as a function of a difference between a target driving frequency f t and the driving frequency.
1. An impedance matching method of a variable reactance impedance matching network disposed between a frequency variable RF power source to vary a driving frequency f and a load, the impedance matching method comprising:
performing a first impedance matching by measuring a first electrical characteristic at an output of a frequency variable RF power source, checking an impedance matching state using the first electrical characteristic at the frequency variable RF power source, and changing a driving frequency of the frequency variable RF power source; and
controlling a variation amount of a capacitance or an inductance of a variable reactive component of the impedance matching network as a function of a difference between a target driving frequency f t and the driving frequency f for inducing the frequency variable RF power source to operate at the target driving frequency.
2. The impedance matching method as set forth in claim 1 , wherein the variation amount of the capacitance or the inductance of the variable reactive component is additionally dependent on a function of a reflection coefficient or impedance for impedance matching.
3. The impedance matching method as set forth in claim 2 , wherein the variable reactive component includes a first capacitor and a second capacitor, and
wherein variation amounts dC 1 and dC 2 of a first capacitance C 1 of the first capacitor and a second capacitance C 2 of the second capacitor satisfy a condition as below,
(
dC
1
dC
2
)
=
(
A
B
)
-
d
ω
ω
(
C
1
C
2
)
where A and B are parameters depending on a reflection coefficient or impedance, and dω represents a difference between a target driving angular frequency (ω t =2πf t ) and a driving angular frequency (ω=2πf).
4. The impedance matching method as set forth in claim 3 , wherein the variation amounts dC 1 and dC 2 of the first capacitance C 1 of the first capacitor and the second capacitance C 2 of the second capacitor satisfy a condition as below,
(
dC
1
dC
2
)
=
g
1
(
A
B
)
-
g
2
d
ω
ω
(
C
1
C
2
)
where g 1 represents a first weighting function and g 2 represents a second weighting function,
wherein the first weighting function is an increasing function of a reflection coefficient, and
wherein the second weighting function is a decreasing function of the reflection coefficient.
5. The impedance matching method as set forth in claim 2 , wherein the step in which the variation amount of the capacitance or the inductance of the variable reactive component is dependent on a function of a reflection coefficient or impedance for impedance matching comprises:
extracting a characteristic vector;
transforming a device vector indicating reactance of a variable reactive component into an analysis vector using a predetermined transformation matrix and expressing the characteristic vector on an analysis coordinate system using the analysis vector as a coordinate axis;
analyzing the characteristic vector on the analysis coordinate system to extract a displacement vector for impedance matching;
transforming the displacement vector into a reduced device vector using the transformation matrix; and
extracting variation amount of capacitance or inductance using the reduced device vector.
6. The impedance matching method as set forth in claim 1 , wherein the variable reactive component includes a first capacitor and a second capacitor, and
wherein variation amounts dC 1 and dC 2 of a first capacitance C 1 of the first capacitor and a second capacitance C 2 of the second capacitor satisfy a condition as below,
(
dC
1
dC
2
)
=
-
d
ω
ω
(
C
1
C
2
)
where dω represents a difference between a target driving angular frequency (ω t =2πf t ) and a driving angular frequency (ω=2πf).
7. The impedance matching method as set forth in claim 1 , wherein the variable reactive component includes a first capacitor and a second capacitor, and
wherein variation amounts dC 1 and dC 2 of a first capacitance C 1 of the first capacitor and a second capacitance C 2 of the second capacitor satisfy a condition as below,
(
dC
1
dC
2
)
=
-
d
ω
ω
(
K
1
K
2
)
where K 1 is a constant, K 2 is a constant, and dω represents a difference between a target driving angular frequency (ω t =2πf t ) and a driving angular frequency (ω=2πf).
8. The impedance matching method as set forth in claim 1 , wherein the variation amount of the capacitance or the inductance of the variable reactive component is controlled to have a negative value when a difference between a target driving frequency f t and the driving frequency f has a positive value, and
wherein the variation amount of the capacitance or the inductance of the variable reactive component is controlled to have a positive value when a difference between a target driving frequency f t and the driving frequency f has a negative value.
9. The impedance matching method as set forth in claim 1 , wherein the frequency variable RF power source performs impedance matching by varying a driving frequency, and
wherein the frequency variable RF power source increases the driving frequency when an imaginary part of a reflection coefficient has a positive value and decreases the driving frequency when the imaginary part of the reflection coefficient has a negative value.
10. The impedance matching method as set forth in claim 1 , wherein the frequency variable RF power source performs impedance matching by varying the driving frequency, and
wherein the frequency variable RF power source performs impedance matching by scanning the driving frequency.
11. A control method of an RF system, comprising:
performing first impedance matching by measuring electrical characteristics at an output of a frequency variable RF power source and varying a driving frequency using the measured electrical characteristics; and
disposing an impedance matching network, including a variable reactive component between the frequency variable RF power source and a load, for changing a capacitance or an inductance of the variable reactive components,
wherein a variation amount of the capacitance or the inductance of the variable reactive component is given as a function between a target driving frequency f t and the driving frequency f for inducing the frequency variable RF power source to operate at the target driving frequency.
12. The control method as set forth in claim 11 , further comprising:
calculating a prediction driving frequency f p and providing the calculated prediction driving frequency f p to the frequency variable RF power source.
13. The control method as set forth in claim 12 , wherein the variable reactive component includes a first capacitor and a second capacitor,
wherein a prediction driving angular frequency ω p is given as below,
ω
p
=
ω
-
ω
(
dC
1
C
1
+
dC
2
C
2
)
where ω p represents a prediction driving angular frequency (ω p =2πf p ), ω represents a driving angular frequency (ω=2πf), C 1 represents first capacitance of the first capacitor, and C 2 represents second capacitance of the second capacitor, and
wherein dC 1 is a variation amount of a first capacitance C 1 of the first capacitor and dC 2 is a variation amount of a second capacitance C 2 of the second capacitor.
14. The control method as set forth in claim 11 , wherein the variation amount of the capacitance or the inductance of the variable reactive component is dependent on a function of a reflection coefficient or impedance for impedance matching.
15. The control method as set forth in claim 14 , the step in which the variation amount of the capacitance or the inductance of the variable reactive component is dependent on a function of a reflection coefficient or impedance for impedance matching comprises:
extracting a characteristic vector;
transforming a device vector indicating reactance of a variable reactive component into an analysis vector using a predetermined transformation matrix and expressing the characteristic vector on an analysis coordinate system using the analysis vector as a coordinate axis;
analyzing the characteristic vector on the analysis coordinate system to extract a displacement vector for impedance matching;
transforming the displacement vector into a reduced device vector using the transformation matrix; and
extracting variation amount of capacitance or inductance using the reduced device vector.
16. The control method as set forth in claim 11 , wherein the variable reactive component includes a first capacitor and a second capacitor, and
wherein variation amounts dC 1 and dC 2 of a first capacitance C 1 of the first capacitor and a second capacitance C 2 of the second capacitor satisfy a condition as below,
(
dC
1
dC
2
)
=
(
A
B
)
-
d
ω
ω
(
C
1
C
2
)
where A and B are parameters depending on a reflection coefficient or impedance, and dω represents a difference between a target driving angular frequency (ω t =2πf t ) and a driving angular frequency (ω=2πf).
17. The control method as set forth in claim 16 , wherein the variation amounts dC 1 and dC 2 of the first capacitance C 1 of the first capacitor and the second capacitance C 2 of the second capacitor satisfy a condition as below,
(
dC
1
dC
2
)
=
g
1
(
A
B
)
-
g
2
d
ω
ω
(
C
1
C
2
)
where g 1 represents a first weighting function and g 2 represents a second weighting function,
wherein the first weighting function is an increasing function of a reflection coefficient, and
wherein the second weighting function is a decreasing function of the reflection coefficient.
18. The control method as set forth in claim 11 , wherein the variable reactive component includes a first capacitor and a second capacitor, and
wherein variation amounts dC 1 and dC 2 of a first capacitance C 1 of the first capacitor and a second capacitance C 2 of the second capacitor satisfy a condition as below,
(
dC
1
dC
2
)
=
-
d
ω
ω
(
C
1
C
2
)
where dω represents a difference between a target driving angular frequency (ω t =2πf t ) and a driving angular frequency (ω=2πf).
19. An impedance matching method of a variable reactance impedance matching network disposed between a frequency variable RF power source to vary a driving frequency f and a load, the impedance matching method comprising:
changing capacitance or inductance of a variable reactive component of the impedance matching network such that the frequency variable RF power source is induced to operate at a target frequency driving frequency.
20. The impedance matching method as set forth in claim 19 , wherein variation amount of capacitance or inductance of a variable reactive component of the impedance matching network is controlled as a function of a difference between a target driving frequency f t and the driving frequency f.
21. The control method as set forth in claim 19 , further comprising:
calculating a prediction driving frequency f p and providing the calculated prediction driving frequency f p to the frequency variable RF power source.
22. An impedance matching method of an RF power system including a frequency variable RF power source and an impedance matching network transferring an output of the frequency variable RF power source to a load, the impedance matching method comprising:
measuring a first electrical characteristic at an output terminal of the frequency variable RF power source;
checking an impedance matching state using the first electrical characteristics by the frequency variable RF power;
varying a driving frequency of the frequency variable RF power source;
measuring a second electrical characteristic at the impedance matching network;
checking an impedance matching state using the second electrical characteristic at the impedance matching network and checking whether a driving frequency is a target driving frequency;
calculating first variation amount of inductance or capacitance of variable reactive component for impedance matching when impedance matching is not performed at the impedance matching network;
calculating second variation amounts of inductance or capacitance of the variable reactive component for varying the driving frequency at the impedance matching network when the driving frequency does not match a target driving frequency; and
calculating the total variation amounts caused by the first variation amount and the second variation amount and controlling the variable reactive component using the total variation amounts.
23. An impedance matching method of an RF power system including a frequency variable RF power source and an impedance matching network transferring an output of the frequency variable RF power source to a load, the impedance matching method comprising:
measuring a first electrical characteristic at an output terminal of the frequency variable RF power source;
checking an impedance matching state using the first electrical characteristic by the frequency variable RF power source;
varying a driving frequency of the frequency variable RF power source;
checking whether the driving frequency is a target driving frequency;
calculating first variation amount of inductance or capacitance of a variable reactive component for impedance matching when impedance matching is not performed;
calculating second variation amount of inductance or capacitance of a variable reactive component for varying a driving frequency when the driving frequency does not match the target driving frequency; and
calculating total variation amount of the first variation amount and the second variation amount and controlling the variable reactive component using the total variation amount.
24. An impedance matching method of an RF power system including a frequency variable RF power source and an impedance matching network transferring an output of the frequency variable RF power source to a load, the impedance matching method comprising:
measuring first electrical characteristics at an output terminal of the frequency variable RF power source;
checking an impedance matching state using the first electrical characteristics by the frequency variable RF power source;
varying a driving frequency of the frequency variable RF power source;
measuring a second electrical characteristic by the impedance matching network;
checking an impedance matching state using the second electrical characteristic by the impedance matching network;
calculating a first variation amount of inductance or capacitance of a variable reactive component for impedance matching; and
controlling the variable reactive component using the first variation amount.
25. An RF power system comprising:
a frequency variable RF power source having a predetermined frequency variable range and varying a driving frequency to perform impedance matching; and
an impedance matching network receiving an output from the frequency variable RF power source and transferring the output to a load,
wherein the impedance matching network changes capacitance or inductance of a variable reactive component of the impedance matching network such that the frequency variable RF power source is induced to operate at a target driving frequency.