CSS-RIP-APSA Controlled Grid Following Neutral Clamped DSTATCOM for Third Harmonic Mitigation

The convergence rate and steady-state error are trade-offs in the conventional adaptive filters used for controlling the three-phase four-wire grid following DSTATCOM. The present paper suggests a combined step size (CSS) real-coefficient improved proportionate (RIP) affine projection sign algorithm (APSA) for DSTATCOM, which is capable of compensating for reactive power, harmonic currents, load and neutral current levels. The proposed controller employs two distinct step sizes, one for speed of convergence and another for steady-state misalignment. A modified sigmoid function is used as a mixing factor, which enables the inverter to serve as a shunt compensator. The primary objective of the proposed controller is to determine the fundamental weight component of distorted load currents, which can then be utilized to compensate for the reactive power and maintain a constant power factor when there are fault conditions and unbalanced grid conditions. The proposed algorithm for grid-tied DSTATCOM is experimentally validated.