Integrated Hierarchical Control Architecture with Adaptive State–Parameter Estimation for a Three-Phase Shunt Active Power Filter

This paper presents a hierarchical estimator-assisted control architecture for a three-phase shunt active power filter (SAPF) for industrial power-quality improvement. The framework combines grid synchronization, harmonic-reference generation, cascaded DC-link and dq-current control, adaptive state–parameter estimation, modulation, and supervisory protection. Numerical and experimental validations are reported separately. In the final 15 kHz switching-model validation of a 400 V, 50 Hz system supplying a six-pulse rectifier load, grid-current THD is reduced from 29.50% to 0.7469%, corresponding to a 97.47% reduction, while the power factor reaches 0.99993. The DC-link voltage is regulated to 750.32 V with 0.0896% ripple. Current- and DC-link-voltage estimation RMSEs are 0.0590 A and 7.76 mV, respectively, and all defined Safe Operating Area criteria are satisfied. Joint online identification yields Rf = 0.03 ohm and Lf = 2.998 mH, with errors of +0.0164% and −0.0667%. On the 15 kHz laboratory prototype, grid-current THD decreases from 29.1% to 2.8%. The proposed architecture provides improved robustness against parameter variations and load disturbances, enhanced observability through online state reconstruction, superior energy regulation, and comprehensive diagnostic capabilities while preserving a computational structure suitable for real-time DSP and FPGA implementation in advanced industrial power-quality conditioning systems. A broader robustness and thermal-estimator validation remain subjects for future work.