Fuzzy active disturbance rejection control for PWM rectifiers under unbalanced grid conditions

Grid voltage imbalances can significantly affect the performance of power electronic converters. A balanced power fuzzy active disturbance rejection control (BPF-ADRC) method is proposed for a three-phase voltage-source pulse width modulation (PWM) rectifier. The method aims to mitigate the adverse effects of grid voltage unbalances on power quality. The approach integrates dual-current balanced power control with active disturbance rejection control (ADRC) to eliminate harmonic components in the system's power. A fuzzy controller is employed to optimize ADRC parameters in real-time, reducing the number of parameters requiring manual tuning and simplifying the overall design process. This integration enhances the system's disturbance rejection capabilities and improves its adaptability to parameter variations under unbalanced grid conditions. Both simulation and experimental results validate the effectiveness of the proposed method. Compared to traditional ADRC and ADRC with power balancing, the proposed algorithm significantly improves steady-state performance. Notably, the grid-side current total harmonic distortion (THD) is reduced from 17.5% to 1.7%. The results demonstrate that the proposed method effectively mitigates the harmonic effects of grid imbalances and provides superior disturbance rejection capabilities.