Repetitive control fractional delay filter design method based on Taylor series expansion

Abstract

Provided is a repetitive control fractional delay filter design method based on Taylor series expansion, belonging to the field of fractional delay filters, and the Taylor series expansion converts the design problem of the fractional delay filter into a differentiator sub-filter design, the structure provides the effective on-line tuning capability, that is, when the delay parameters change, andthe fractional delay filter can easily generate any required fractional delay without redesign of the filter. The method is applied to a repeated controller, and the fractional delay filter structureis improved, the harmonic compensation under the condition of the variable frequency reference signal is realized, and compared with the FORC, the repeated controller based on the Taylor series expansion only has one delay parameter to be calculated and updated in real time, so that the control system is stable, and the harmonic frequency self-adaptive tracking can be realized through the combination with the design method of an optimal fractional delay filter, and an ideal harmonic compensation effect is achieved.

Description

technical field [0001] The invention belongs to the field of fractional delay filters, in particular to a design method for repeated control fractional delay filters based on Taylor series expansion. Background technique [0002] In practice, the grid frequency usually varies within a certain range, and the order N of repeated control is often a fraction under a fixed sampling frequency. The composite current control strategy based on the traditional repetitive controller is very sensitive to the change of the grid frequency and cannot accurately compensate the fractional period signal, because in practice only z -N It can only be achieved with an integer N, so under the condition of grid frequency change, the parallel active power filter (SAPF) cannot suppress all harmonics, which affects the compensation effect. [0003] In order to avoid problems caused by grid frequency changes, there are mainly two methods currently used: one is a repetitive controller with variable sa...

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Problems solved by technology

[0005] Aiming at the influence of power grid frequency fluctuation on the steady-state accuracy of SAPF control system based on traditional repetitive control, the present invention proposes a repetitive control fractional delay filter design method based on Taylor series expansion

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