Design and Experimental Investigation of a Three-Phase APF based on Feed-Forward plus Feedback Control

An effective control scheme for three-phase three-wire active power filter is proposed in this paper. Conventionally, the majority of existing APF control strategies in literature adopts feed-forward control scheme, which results in switching notches (sharp-rising or falling ripples) in the source-side currents at conduction instants of diode/thyristor rectifier load. The proposed method utilizes feedback control plus feed-forward control structures to achieve a smooth filtering performance. The feedback loop minimizes the steady-state error using two separate PI regulators in d-axis and q-axis respectively. The feed-forward loop serves the purpose of load disturbance rejection and it significantly enhances performance of active power filter by using synchronous frame adaptive neural network (SADALINE) algorithm. The proposed method overwhelms many existing compensation schemes in terms of simplicity, robustness and ease of implementation using DSP. The effectiveness of the proposed control scheme has been substantially confirmed by experimental results. Key-Words: harmonic contamination, active filter, power quality, SADALINE