摘要

The traditional repetitive controller has relatively worse stability and poor transient performance because it generates infinite gain at all the integer multiples of the fundamental frequency, and its control action is postponed by one fundamental period (T-0). To improve these disadvantages, many repetitive controllers with reduced delay time have been proposed, which can selectively compensate the odd harmonics or 6k +/- 1 harmonics with delay time reduced to T-0/2 and T-0/3, respectively. To further study in this area, this paper proposes an improved repetitive scheme implemented in a stationary reference frame, which only compensates the 6k + 1 harmonics (e.g., -5, +7, -11, +13) in three-phase systems and reduces the time delay to T-0/6. Thus compared with the earlier reduced delay time repetitive controllers, the robustness and transient performance is further improved, the waste of control effort is reduced, and the possibility of amplifying and even injecting any harmonic noises into the system is avoided to a great extent. Moreover, the proposed repetitive scheme is used in the control of a three-phase hybrid active power filter. The experimental results validate the effectiveness of the proposed repetitive control scheme.