A new algorithm of time domain synchronous averaging analysis

The speed of rotary machine varies with the fluctuation of voltage and load. And the method of period-based time domain synchronous averaging can not process the case of fluctuation of rotation speed because of the phase errors accumulation from the errors of round-off and frequency estimation. In order to solve the problem, a modified method of period-based time domain synchronous averaging is proposed in this paper. The idea is to get the frequency of per rotation by using FFT-FS (fast Fourier transform-Fourier series). This method can improve the effectiveness of the phase error accumulation. Simulation and experiment results have shown that the new algorithm is excellent on extracting the periodic of signal from speed fluctuation signal.