Adaptive periodic waveform controller
A repeating setpoint generator module selectively varies a setpoint for an output parameter according to a predetermined pattern that repeats during successive time intervals. A closed-loop module, during a first one of the time intervals, generates N closed-loop values based on N differences between (i) N values of the setpoint at N times during the first one of the time intervals and (ii) N measurements of the output parameter at the N times during the first one of the time intervals, respectively. An adjusting module, during the first one of the time intervals, generates N adjustment values based on N differences between (i) N values of the setpoint at the N times during a second one of the time intervals and (ii) N measurements of the output parameter at the N times during the second one of the time intervals, respectively.
1. A method of generating an output power, the method comprising:
selectively varying a setpoint for an output parameter according to a predetermined pattern that repeats during successive time intervals;
during a first one of the time intervals, generating N closed-loop values based on N differences between (i) N values of the setpoint at N times during the first one of the time intervals and (ii) N measurements of the output parameter at the N times during the first one of the time intervals, respectively;
during the first one of the time intervals, generating N adjustment values based on N differences between (i) N values of the setpoint at the N times during a second one of the time intervals and (ii) N measurements of the output parameter at the N times during the second one of the time intervals, respectively, wherein the second one of the time intervals is the time interval immediately preceding the first one of the time intervals;
applying, using a power amplifier, output power to a load;
generating N output values based on the N closed-loop values and the N adjustment values, respectively; and
controlling power input to the power amplifier based on the N output values.
2. The method of claim 1 wherein the N times are equally spaced.
3. The method of claim 1 wherein the N times are not equally spaced.
4. The method of claim 1 wherein generating the N closed-loop values comprises generating the N closed-loop values using proportional-integral (PI) control.
5. The method of claim 1 wherein generating the N adjustment values comprises generating the N adjustment values using proportional-integral (PI) control.
6. The method of claim 1 further comprising:
generating the N output values further based on a mixing ratio; and
selectively varying the mixing ratio.
7. The method of claim 1 further comprising selectively adjusting a fundamental frequency of the power amplifier.
8. The method of claim 7 further comprising selectively adjusting the fundamental frequency of the power amplifier based on a reflected power.
9. The method of claim 7 further comprising selectively adjusting the fundamental frequency of the power amplifier based on a reflection coefficient.
10. The method of claim 1 further comprising applying, using the power amplifier, the output power to a plasma electrode.
11. The method of claim 1 further comprising:
determining a distortion of the output power; and
selectively adjusting a fundamental frequency of the power amplifier based on the distortion.
12. The method of claim 11 further comprising:
determining a first frequency adjustment based on the distortion and at least one previous amount of distortion of the output power;
determining a second frequency adjustment based on at least one previous amount of distortion of the output power; and
setting the fundamental frequency of the power amplifier based on a previous fundamental frequency of the power amplifier, the first frequency adjustment, and the second frequency adjustment.
13. The method of claim 12 further comprising determining the second frequency adjustment based on at least one previous value of the second frequency adjustment.
14. A method of generating an output power, the method comprising:
selectively varying a setpoint for an output parameter according to a predetermined pattern that repeats during successive time intervals;
during a first one of the time intervals, generating N adjustment values based on N differences between (i) N values of the setpoint at N times during a second one of the time intervals and (ii) N measurements of the output parameter at the N times during the second one of the time intervals, respectively, wherein the second one of the time intervals is the time interval immediately preceding the first one of the time intervals;
generating N output values based on N closed-loop values and the N adjustment values, respectively; and
controlling power input to a power amplifier based on the N output values.
15. The method of claim 14 further comprising during the first one of the time intervals, generating the N closed-loop values based on N differences between (i) N values of the setpoint at the N times during the first one of the time intervals and (ii) N measurements of the output parameter at the N times during the first one of the time intervals, respectively.
16. The method of claim 15 further comprising applying, using a power amplifier, the output power to a load.
17. The method of claim 14 further comprising applying, using a power amplifier, the output power to a load.
18. The method of claim 14 wherein the N times are equally spaced.
19. The method of claim 14 wherein the N times are not equally spaced.
20. The method of claim 14 wherein generating the N closed-loop values comprises generates the N adjustment values using at least one of proportional, integral, or derivative control.
21. The method of claim 14 further comprising:
generating the N output values further based on a mixing ratio; and
selectively varying the mixing ratio.
22. The method of claim 14 further comprising selectively adjusting a fundamental frequency of the output power.
23. The method of claim 22 further comprising selectively adjusting the fundamental frequency of the output power based on a reflected power.
24. The method of claim 22 further comprising selectively adjusting the fundamental frequency of the output power based on a reflection coefficient.
25. The method of claim 14 further comprising applying, using a power amplifier, the output power to a plasma electrode.
26. The method of claim 14 further comprising:
determining a distortion of the output power; and
selectively adjusting a fundamental frequency of the power amplifier based on the distortion.
27. The method of claim 14 further comprising:
determining a first frequency adjustment based on the distortion and at least one previous amount of distortion of the output power;
determining a second frequency adjustment based on at least one previous amount of distortion of the output power; and
setting the fundamental frequency of the power amplifier based on a previous fundamental frequency of the power amplifier, the first frequency adjustment, and the second frequency adjustment.
28. The method of claim 27 further comprising determining the second frequency adjustment based on at least one previous value of the second frequency adjustment.