System and method for harmonic control of dual-output generators
A dual-output generator is configured to output two or more waveforms at different frequencies. In particular, the dual-output generator is configured to provide low-frequency output, which may be suitable for ultrasonic surgical instruments, and a high-frequency output, which may be suitable for electrosurgical instruments, while reducing the amplitude of all remaining frequencies other than the two selected low and high frequencies to about zero.
1. A method for controlling a dual-output electrosurgical generator, the method comprising:
outputting a direct current (DC) waveform from a power supply;
supplying a switching angle waveform to an inverter coupled to the power supply, the inverter including at least one switching element operated at a switching angle; and
modulating the switching angle by a controller using dual-frequency selective harmonic elimination modulation to:
simultaneously generate a first waveform at a first frequency and a secondary waveform at a second frequency, and
eliminate at least one harmonic waveform between the first frequency and the second frequency.
2. The method according to claim 1 , wherein the first frequency is a fundamental frequency.
3. The method according to claim 2 , wherein the second frequency is a harmonic frequency of the fundamental frequency.
4. The method according to claim 1 , further comprising:
outputting the first waveform through a low-frequency filter coupled to the inverter.
5. The method according to claim 1 , further comprising:
outputting the second waveform through a high-frequency filter coupled to the inverter.
6. The method according to claim 1 , wherein the at least one switching element includes four switching elements arranged in an H-bridge topology.
7. The method according to claim 6 , wherein each of the four switching elements is a wide bandgap field effect transistor.
8. The method according to claim 1 , wherein the second frequency is higher than the first frequency.
9. A method for performing electrosurgery, the method comprising:
outputting a direct current (DC) waveform from a power supply;
supplying a switching angle waveform to an inverter coupled to the power supply, the inverter including at least one switching element operated at a switching angle; and
modulating the switching angle by a controller using dual-frequency selective harmonic elimination modulation to:
simultaneously generate a first waveform at a first frequency and a secondary waveform at a second frequency; and
eliminate at least one harmonic waveform between the first frequency and the second frequency;
outputting the first waveform through a first output;
outputting the second waveform through a second output;
energizing via the first waveform a first instrument coupled to the first output; and
energizing via the second waveform a second instrument coupled to the second output.
10. The method according to claim 9 , wherein the first instrument is an ultrasonic instrument including a transducer energizable by the first waveform.
11. The method according to claim 9 , wherein the first instrument is a first electrosurgical instrument including at least one first electrode configured to contact tissue and transmit the first waveform thereto.
12. The method according to claim 9 , wherein the second instrument is an electrosurgical instrument including at least one second electrode configured to contact tissue and transmit the second waveform thereto.
13. The method according to claim 9 , wherein the first frequency is a fundamental frequency.
14. The method according to claim 13 , wherein the second frequency is a harmonic frequency of the fundamental frequency.
15. The method according to claim 9 , further comprising:
outputting the first waveform through a low-frequency filter coupled to the inverter.
16. The method according to claim 9 , further comprising:
outputting the second waveform through a high-frequency filter coupled to the inverter.
17. The method according to claim 9 , wherein the at least one switching element includes four switching elements arranged in an H-bridge topology.
18. The method according to claim 17 , wherein each of the four switching elements is a wide bandgap field effect transistor.
19. The method according to claim 9 , wherein the second frequency is higher than the first frequency.