Prediction control of active power filters

Abstract

A prediction method to obtain harmonic reference for active power filter is presented. It is a new use of the adaptive predictive filter based on FIR. The delay inherent in digital controller is successfully compensated by using the proposed method, and the computing load is not very large compared with the conventional method. Moreover, no additional hardware is needed. Its DSP-based realization is also presented, which is characterized by time-variant rate sampling, quasi synchronous sampling, and synchronous operation among the line frequency, PWM generating and sampling in A/D unit. Synchronous operation releases the limitation on PWM modulation ratio and guarantees that the electrical noises resulting from the switching operation of IGBTs do not interfere with the sampled current. The simulation and experimental results verify the satisfactory performance of the proposed method.

Keywords

active filter / prediction method / time-variant rate sampling / quasi synchronous sampling