Systems and methods for suppressing pressure waves using corrective signal

A corrective modulation system for providing a corrective modulation signal to suppress an acoustic pressure wave in an operational system, the system comprising:

• a pressure sampling device that samples the acoustic pressure wave generated in the operational system to provide a sample of the acoustic pressure wave;
• a phase output portion, the phase output portion providing a sample of a phase of a previously generated corrective modulation;
• a signal processing portion that processes the sample of the acoustic pressure wave and the sample of the phase of the previously generated corrective modulation, the signal processing portion including:
• a fast Fourier transform processing portion that performs a fast Fourier transform process on the sample of the acoustic pressure wave, the signal processing portion generating frequency with maximum power information and maximum power information based on the fast Fourier transform process;
• at least two discrete Fourier transform processing portions that perform single frequency discrete Fourier transform processing, the signal processing portion generating pressure phase information based on the single frequency discrete Fourier transform processing, and
• a modulation phase processing portion, the modulation phase processing portion generating modulation phase information based on the sample of the phase of the previously generated corrective modulation;
• and
• a corrective modulation generator that generates a sinusoidal corrective modulation signal to suppress the acoustic pressure wave based on the frequency with maximum power information and maximum power information, the pressure phase information, and the modulation phase information, wherein the corrective modulation signal being at substantially the same frequency as, and generally 180 degrees out of phase with, the acoustic pressure wave.

A system for providing a corrective modulation signal to suppress an acoustic pressure wave in an operational system, the system comprising:

• means for sampling the acoustic pressure wave generated in the operational system;
• means for sampling a previously generated corrective modulation signal, the previously generated corrective modulation signal having parameters;
• means for performing fast Fourier transform processing on the sampled acoustic pressure wave;
• means for performing a pair of single frequency discrete Fourier transform processing on the sampled acoustic pressure wave;
• means for determining the frequency, phase and magnitude of a dominate pressure wave in the acoustic pressure wave based on the fast Fourier transform processing and the discrete Fourier transform processing;
• and
• means for generating a sinusoidal corrective modulation signal to suppress the acoustic pressure wave based on the frequency, phase and magnitude of the dominate pressure wave and the parameters of the previously generated corrective modulation signal, the corrective modulation signal being at substantially the same frequency as, and generally 180 degrees out of phase with, the acoustic pressure wave.

A method for providing a corrective modulation signal to suppress an acoustic pressure wave in a gas turbine system, the method comprising the steps of:

• sampling the acoustic pressure wave generated in the gas turbine system;
• sampling a previously generated corrective modulation signal, the previously generated corrective modulation signal having parameters;
• performing fast Fourier transform processing on the sampled acoustic pressure wave;
• performing a pair of single frequency discrete Fourier transform processing on the sampled acoustic pressure wave;
• determining the frequency, phase and magnitude of a dominate pressure wave in the acoustic pressure wave based on the fast Fourier transform processing and the discrete Fourier transform processing;
• generating a sinusoidal corrective modulation signal to suppress the acoustic pressure wave based on the frequency, phase and magnitude of the dominate pressure wave and the parameters of the previously generated corrective modulation signal, the corrective modulation signal being at substantially the same frequency as, and generally 180 degrees out of phase with, the acoustic pressure wave;
• generating a frequency error;
• generating a phase error;
• and
• providing a gain control based on the frequency error, the phase error and the magnitude of the dominate pressure wave, the gain control generating a gain signal to adjust the corrective modulation signal.

A corrective modulation system for providing a corrective modulation signal to suppress an acoustic pressure wave in an operational system, the system comprising:

• a pressure sampling device that samples the acoustic pressure wave generated in the operational system to provide a sample of the acoustic pressure wave;
• a phase output portion, the phase output portion providing a sample of a previously generated corrective modulation;
• a signal processing portion that processes the sample of the acoustic pressure wave and the sample of the previously generated corrective modulation, the signal processing portion including:
• a fast Fourier transform processing portion that performs a fast Fourier transform process on the sample of the acoustic pressure wave, the signal processing portion generating frequency with maximum power information and maximum power information based on the fast Fourier transform process;
• at least one discrete Fourier transform processing portion that performs single frequency discrete Fourier transform processing, the single frequency discrete Fourier transform processing including performing a first single frequency discrete Fourier transform on a first part of the sample, which is processed by the signal processing portion to generate pressure phaseK information, and performing a second single frequency discrete Fourier transform on a second part of the sample, which is processed by the signal processing portion to generate pressure phaseK-1 information, and
• a modulation phase processing portion, the modulation phase processing portion generating modulation phaseK information and modulation phaseK-1 information based on the sample of the previously generated corrective modulation;
• a corrective modulation generator that generates a sinusoidal corrective modulation signal to suppress the acoustic pressure wave based on:
• the frequency with maximum power information and maximum power information;
• the pressure phaseK information and the pressure phaseK-1 information;
• and
• modulation phaseK information and modulation phaseK-1 information;
• and
• the corrective modulation signal being at substantially the same frequency as, and generally 180 degrees out of phase with, the acoustic pressure wave.

A system for providing a corrective modulation signal to suppress an acoustic pressure wave in a gas turbine, the system comprising:

• means for sampling the acoustic pressure wave generated in the gas turbine;
• means for sampling a previously generated corrective modulation signal, the previously generated corrective modulation signal having parameters;
• means for performing fast Fourier transform processing on the sampled acoustic pressure wave;
• means for performing a pair of single frequency discrete Fourier transform processing on the sampled acoustic pressure wave;
• means for determining the frequency, phase and magnitude of a dominate pressure wave in the acoustic pressure wave based on the fast Fourier transform processing and the discrete Fourier transform processing;
• means for generating a sinusoidal corrective modulation signal to suppress the acoustic pressure wave based on the frequency, phase and magnitude of the dominate pressure wave and the parameters of the previously generated corrective modulation signal, the corrective modulation signal being at substantially the same frequency as, and generally 180 degrees out of phase with, the acoustic pressure wave;
• means for generating a frequency error;
• means for generating a phase error;
• and
• means for providing a gain control based on the frequency error, the phase error and the magnitude of the dominate pressure wave, the gain control generating a gain signal to adjust the corrective modulation signal.