Distortion correction based feedforward control systems and methods for radio frequency power sources

• US 8,781,415 B1
• Filed: 02/07/2013
• Issued: 07/15/2014
• Est. Priority Date: 02/07/2013
• Status: Active Grant

• Current Assignee: MKS Instruments Incorporated
• Original Assignee: MKS Instruments Incorporated
• Inventors: Coumou, David J., Fisk, Larry J.
• Primary Examiner(s): VO, NGUYEN THANH
• Application Number:
  US13/761,679
• Publication Number:
  US 20140220913A1
• Time in Patent Office: 523 Days
• Field of Search: 455/107, 455/114.2, 455/114.3, 455/125, 375/296, 375/297, 330/149, 330/302, 330/305, 333/17.3, 333/32, 323/364
• US Class Current: 455/114.3
• CPC Class Codes: H01J 37/32183 Matching circuits
• CPC Class Codes: H01J 37/32935 Monitoring and controlling tubes by information coming from the object and/or discharge
• CPC Class Codes: H03H 7/40 Automatic matching of load impedance to source impedance

Abstract

A distortion module includes a first module, at least one module and a correction module. The first module is configured to (i) receive radio frequency signals from radio frequency sensors of a power amplifier, and (ii) generate a distortion signal indicating distortion values for the radio frequency signals. The radio frequency signals are indicative of radio frequency power out of the power amplifier and received by a transmission line. At least one module is configured to estimate a phase of the distortion signal. The phase of the distortion signal is indicative of a phase of the transmission line. The correction module is configured to generate a distortion correction signal based on the phase to correct at least one of the distortion values of the radio frequency signals.

Claims

1. A distortion module comprising:

a first module configured to (i) receive radio frequency signals from radio frequency sensors of a power amplifier, and (ii) generate a distortion signal indicating distortion values for the radio frequency signals, wherein the radio frequency signals are indicative of radio frequency power out of the power amplifier and received by a transmission line;

at least one module configured to estimate a phase of the distortion signal, wherein the phase of the distortion signal is indicative of a phase of the transmission line; and

a correction module configured to generate a distortion correction signal based on the phase to correct at least one of the distortion values of the radio frequency signals.

2. The distortion module of claim 1, further comprising:

a derivative module configured to, based on the distortion values of the distortion signal, determine derivative values of a derivative of a distortion function or the distortion signal to generate a derivative signal,

wherein the first module is configured to generate the distortion signal based on the distortion function;

a translation module configured to determine an offset translation based on the derivative values of the derivative signal; and

a phase module configured to determine the phase of the distortion signal based on the offset translation.

3. The distortion module of claim 2, further comprising:

a sampling module configured to sample the distortion signal to obtain the distortion values; and

a matrix module configured to generate a matrix based on the derivative values of the derivative signal,

wherein the translation module is configured to generate the offset translation based on the matrix.

4. The distortion module of claim 3, wherein the offset translation is determined based on a least squares estimate of the matrix.

5. The distortion module of claim 4, wherein the matrix module configured to generate the matrix based on:

a predetermined number of samples of the distortion signal; and

a predetermined number of samples of the derivative signal.

6. The distortion module of claim 2, wherein the first module is configured to generate the distortion signal according to at least one of (i) a sinusoidal function of the radio frequency signals and (ii) a cross-correlation function of the radio frequency signals.

7. The distortion module of claim 2, wherein:

the phase module is configured to generate a phase correction signal based on the phase; and

the correction module is configured to generate the distortion correction signal based on the phase correction signal.

8. A radio frequency system comprising:

the distortion module of claim 2;

the power amplifier configured to provide an output to a matching network via the transmission line between the power amplifier and the matching network; and

the radio frequency sensors configured to (i) monitor the output of the power amplifier, and (ii) generate the radio frequency signals.

9. The radio frequency system of claim 8, further comprising a control module configured to (i) generate a impedance tuning value based on the distortion correction signal, and (ii) provide feedforward control of impedance matching performed within the matching network including outputting the impedance tuning value to one of the power amplifier and the matching network.

10. The radio frequency system of claim 9, further comprising a gain module configured to determine a gain value based on the derivative values of the derivative signal to account for a resolution of an impedance tune space associated with the transmission line,

wherein the control module is configured to generate the impedance tuning value based on the gain value.

11. The radio frequency system of claim 10, wherein the control module adjusts coefficients of the impedance tuning value based on the gain value.

12. A distortion module comprising:

a function module configured to (i) receive radio frequency signals from radio frequency sensors of a power amplifier, and (ii) generate a distortion signal indicating distortion values for the radio frequency signals based on a distortion function;

a first derivative module configured to, based on the distortion values of the distortion signal, determine first derivative values of a first derivative of the distortion function or the distortion signal to generate a first derivative signal;

a second derivative module configured to, based on the first derivative values or the first derivative signal, determine second derivative values of a second derivative of the distortion signal to generate a second derivative signal;

a phase module configured to (i) determine a first phase of the first derivative signal and a second phase of the second derivative signal, and (ii) determine a first phase correction value based on the first phase and the second phase; and

a correction module configured to generate a distortion correction signal based on the first phase correction value.

13. The distortion module of claim 12, further comprising:

a first comparison module configured to compare the first phase of the first derivative signal to π

/2 to generate a second phase correction value; and

a second comparison module configured to compare the second phase of the second derivative signal to IT to generate a third phase correction value,

wherein the first phase correction value is generated based on the second phase correction value and the third phase correction value.

14. The distortion module of claim 13, further comprising:

a first extrapolation module configured to extrapolate the first phase of the first derivative signal for an angular position associated with a maximum amount of power transfer from a power generator to a transmission line,

wherein the first comparison module is configured to generate the second phase correction value based on the extrapolated first phase; and

a second phase extrapolation module configured to extrapolate the second phase of the second derivative signal for the angular position associated with the maximum amount of power transfer from the power generator to the transmission line,

wherein the second comparison module is configured to generate the third phase correction value based on the extrapolated second phase.

15. The distortion module of claim 14, further comprising a third comparison module configured to compare the second phase correction value to the third phase correction value to generate the first phase correction value.

16. A radio frequency system comprising:

the distortion module of claim 12;

the power amplifier configured to provide an output to a matching network via a transmission line between the power amplifier and the matching network; and

the radio frequency sensors configured to (i) monitor the output of the power amplifier, and (ii) generate the radio frequency signals.

17. The radio frequency system of claim 16, further comprising a control module configured to (i) generate a first impedance tuning value based on the distortion correction signal, and (ii) provide feedforward control of impedance matching performed within the matching network including outputting the first impedance tuning value to one of the power amplifier and the matching network.

18. The radio frequency system of claim 17 further comprising a gain module configured to determine a gain value based on the derivative values of the derivative signal to account for a resolution of an impedance tune space associated with the transmission line,

wherein the control module is configured to generate the impedance tuning value based on the gain value.

19. The radio frequency system of claim 18, wherein the control module is configured to adjust coefficients of the impedance tuning value based on the gain value.

20. A radio frequency system comprising:

a power amplifier configured to output a radio frequency signal to a matching network via a transmission line between the power amplifier and the matching network;

a sensor configured to monitor the radio frequency signal and generate first sensor signals based on the radio frequency signal;

a distortion module configured to determine distortion values according to at least one of (i) a sinusoidal function of the first sensor signals and (ii) a cross-correlation function of the first sensor signals;

a derivative module configured to determine derivative values for a derivative of a distortion function based on the distortion values;

a gain module configured to determine a gain value based on the derivative values to account for a resolution of an impedance tune space associated with the transmission line; and

a control module configured to (i) generate an impedance tuning value based on the distortion values and the gain value, and (ii) provide feedforward control of impedance matching performed within the matching network including outputting the impedance tuning value to one of the power amplifier and the matching network.

21. The radio frequency system of claim 20, wherein the power amplifier is configured to adjust frequency of the radio frequency signal to the matching network based on the impedance tuning value.

22. The radio frequency system of claim 20, further comprising the matching network, wherein the matching network is configured to adjust an impedance in the matching network based on the impedance tuning value.