Improving the dynamic response of active power filters based on the synchronous reference frame method

This paper presents a new strategy for improving the dynamic response of active power filters that use the synchronous reference frame method (i_d-i_q method). The strategy is based on the substitution of conventional filtering by a efficient, faster and simpler process requesting less computational burden. Such modification produces a faster transient response during compensation process that lasts 1/6 of the fundamental voltage period (or 1/3, if there is even order harmonics in the currents). Due to its fast response, the proposed modification makes it possible the application of the id-iq method to a single phase. With such a feature, this method becomes suitable for the harmonic compensation of unbalanced loads, still keeping a fast dynamic response. The paper describes the strategy and presents the simulations and the experimental results