Vector Repetitive Control Based on Harmonic Sequence Extraction for Shunt Active Power Filters

Repetitive control (RC), which is widely applied in many fields, can track or eliminate periodic signals with almost zero steady-state error. However, the conventional RC (CRC) has a slow transient response so that it usually has to be used in combination with other fast control to adapt to high performance application's request. In this paper, a vector repetitive control (VRC) for shunt active power filters (SAPF) is proposed. The VRC controller can speed up error convergence rate, and even make RC be not a slow control anymore by reforming the internal model of the CRC. Additionally, for a SAPF or other applications where harmonics need to be extracted, a harmonic sequence extraction based on trigonometric function delay signal cancellation (TFDSC-HSE) is proposed too. The proposed scheme (TFDSC-HSE+VRC) accelerates real-time tracking rate while maintaining outstanding steady-state response. A practical case study on a three-phase SAPF is conducted. The feasibility and effectiveness of the proposed scheme are verified by experiments.