Stability analysis of periodic orbit of an adaptive notch filter for frequency estimation of a periodic signal

Automatica ◽  
2007 ◽  
Vol 43 (3) ◽  
pp. 450-455 ◽  
Author(s):  
M. Mojiri ◽  
A.R. Bakhshai
Keyword(s):  
Stability Analysis ◽  
Periodic Orbit ◽  
Frequency Estimation ◽  
Notch Filter ◽  
Periodic Signal ◽  
Adaptive Notch Filter

scholarly journals A Novel Adaptive Frequency Estimation Algorithm Based on Interpolation FFT and Improved Adaptive Notch Filter

2017 ◽  
Vol 17 (1) ◽  
pp. 48-52 ◽  
Author(s):  
Ting-ao Shen ◽  
Hua-nan Li ◽  
Qi-xin Zhang ◽  
Ming Li
Keyword(s):  
Convergence Rate ◽  
High Frequency ◽  
Frequency Estimation ◽  
Notch Filter ◽  
Estimation Algorithm ◽  
Signal Frequency ◽  
Tracking Accuracy ◽  
Frequency Tracking ◽  
Adaptive Notch Filter ◽  
Fast Estimation

Abstract The convergence rate and the continuous tracking precision are two main problems of the existing adaptive notch filter (ANF) for frequency tracking. To solve the problems, the frequency is detected by interpolation FFT at first, which aims to overcome the convergence rate of the ANF. Then, referring to the idea of negative feedback, an evaluation factor is designed to monitor the ANF parameters and realize continuously high frequency tracking accuracy. According to the principle, a novel adaptive frequency estimation algorithm based on interpolation FFT and improved ANF is put forward. Its basic idea, specific measures and implementation steps are described in detail. The proposed algorithm obtains a fast estimation of the signal frequency, higher accuracy and better universality qualities. Simulation results verified the superiority and validity of the proposed algorithm when compared with original algorithms.

scholarly journals Speed Fluctuation Suppression for the Inverter Compressor Based on the Adaptive Revised Repetitive Controller

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6342
Author(s):  
Fankun Meng ◽  
Xiaoning Zhang ◽  
Zhengguo Li ◽  
Xiaoqin Wen ◽  
Linru You
Keyword(s):  
Frequency Estimation ◽  
Tracking Error ◽  
Notch Filter ◽  
Periodic Signal ◽  
Delay Element ◽  
Periodic Load ◽  
Resonant Frequencies ◽  
Fixed Integer ◽  
Speed Fluctuation ◽  
Repetitive Controller

Repetitive operation is extensively present in the inverter compressor refrigeration field. Research illustrates that an approximate periodic load disturbance deteriorates its self-sensing and efficiency in a low frequency range. According to an internal model theorem, a repetitive controller can realize periodic signal tracking or suppression; however, ideal repetitive control (IRC) can not be directly employed in practical application owing to its excessive sensitivity to period-time uncertainties or aperiodic component, etc. In addition, the ratio between period delay to sampling time can not always maintain an integer which causes the resonant frequencies to deviate from the interested. Even if the ratio is a fixed integer, the auxiliary function for stabilization in a conventional repetitive controller can result in the steady state tracking error. In this paper, a revised repetitive controller with a novel Savitzky–Golay (S–G) filter is proposed, the S–G filter cascaded with a traditional delay element can approximate the delay element with any ratio. Aiming at a different operating condition, a second order generalized integrator (SOGI) based observer is employed to extract disturbance fundamental component, and Steiglitz–McBride based adaptive notch filter (SM-ANF) is adopted for frequency estimation. The proposed scheme varies the S–G filter according to variable fundamental frequency and maintains its resonant frequencies corresponding with the fundamental and harmonic disturbance. In the end, simulations and experiments are implemented and results illustrate that speed fluctuation can be effectively suppressed by the proposed method.

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