Fractional delay filter based repetitive control for precision tracking: Design and application to a piezoelectric nanopositioning stage

2022 ◽  
Vol 164 ◽  
pp. 108249
Author(s):  
Zhao Feng ◽  
Min Ming ◽  
Jie Ling ◽  
Xiaohui Xiao ◽  
Zhi-Xin Yang ◽  
...  
Keyword(s):  
Repetitive Control ◽  
Fractional Delay ◽  
Precision Tracking ◽  
Fractional Delay Filter ◽  
Design And Application

scholarly journals A Frequency Adaptive Scheme Based on Newton Structure of PRRC for LCL-Type Inverter Connected with Weak Grid

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4225
Author(s):  
Chengbi Zeng ◽  
Sudan Li ◽  
Hanwen Wang ◽  
Hong Miao
Keyword(s):  
Repetitive Control ◽  
Harmonic Distortion ◽  
Adaptive Scheme ◽  
Computational Burden ◽  
Weak Grid ◽  
Control Scheme ◽  
Sample Frequency ◽  
Fractional Delay ◽  
Pr Controller ◽  
Online Tuning

Repetitive control (RC) is gradually used in inverters tied with weak grid. To achieve the zero steady-state error tracking of inverter current and compensate the harmonic distortion caused by frequency fluctuation, a frequency adaptive (FA) control scheme for LCL-type inverter connected with weak grid is proposed. This scheme adopts a proportional resonance (PR) controller in parallel with RC (PRRC) to overcome the disadvantages caused by RC inherent one-cycle time delay. A fractional delay (FD) filter based on the Newton structure is proposed to approximate the fraction item of fs/f, where fs and f are sample frequency and grid frequency, respectively. The structure of the proposed FD filter is relatively simple; moreover, coefficients of the filter maintain constant so as not to need online tuning even when grid frequency fluctuates, which decreases the computational burden considerably. The feasibility and effectiveness of the proposed FA control scheme, named as Newton-FAPRRC, are all verified by the simulation and experimental results.

scholarly journals Design of Variable Fractional Delay Filter using FIR Filter Approximation

2019 ◽  
Vol 8 (4) ◽  
pp. 5932-5936
Keyword(s):  
Interpolation Method ◽  
Fir Filter ◽  
Beam Forming ◽  
Rf Signals ◽  
Direct Form ◽  
Fractional Delay ◽  
Filter Approximation ◽  
Fractional Delay Filter ◽  
Is Design

Beamforming plays an important role in the field of wireless communication. Beamforming means combination of a radio frequency (RF) signals from multiple antennas to form a single direction beam. This technique improves the quality of communication and reduces the interference of signal. In beam forming technique, different phases signals can be achieved with different signals and the received phase delay signals are converted into same phase, multiply with weight factor and combined this signals to form a beam in desired direction. The required phase delays are generated by using a Variable fractional delay filter. Variable fractional delay filter is design by using a direct form of a FIR filter structure. Variable fractional delay filter is calculated by two different phase signals from digital antennas and those two different phase signals are converted to in- phase and added together to form a beam forming. As the order of the filter increases, the delay also increases. The filter coefficients of the variable fractional delay filter are calculated my using a Lagrange interpolation method. The variable fractional delay filter is designed by using software Xilinx version 14.3

Variable Ratio Sample Rate Conversion Based on Fractional Delay Filter

2015 ◽  
Vol 39 (2) ◽  
pp. 231-242 ◽  
Author(s):  
Marek Blok ◽  
Piotr Drózda
Keyword(s):  
Speech Signal Processing ◽  
Farrow Structure ◽  
Conversion Algorithm ◽  
Window Method ◽  
Voiced Speech ◽  
Fractional Delay ◽  
Sample Rate ◽  
Fractional Delay Filter ◽  
Speech Segments ◽  
Rate Conversion

Abstract In this paper a sample rate conversion algorithm which allows for continuously changing resampling ratio has been presented. The proposed implementation is based on a variable fractional delay filter which is implemented by means of a Farrow structure. Coefficients of this structure are computed on the basis of fractional delay filters which are designed using the offset window method. The proposed approach allows us to freely change the instantaneous resampling ratio during processing. Using such an algorithm we can simulate recording of audio on magnetic tape with nonuniform velocity as well as remove such distortions. We have demonstrated capabilities of the proposed approach based on the example of speech signal processing with a resampling ratio which was computed on the basis of estimated fundamental frequency of voiced speech segments.

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