); [EMAIL_ADDRESS] (C.L. ); [EMAIL_ADDRESS] (Z.L. ); [EMAIL_ADDRESS] (H.L. ); [EMAIL_ADDRESS] (J.S. ); [EMAIL_ADDRESS] (S.J.) Hongxu Li  
College of Electrical Engineering and Information, Northeast Agricultural University, Harbin 150030, China; [EMAIL_ADDRESS] (K.S. ); [EMAIL_ADDRESS] (C.L. ); [EMAIL_ADDRESS] (Z.L. ); [EMAIL_ADDRESS] (H.L. ); [EMAIL_ADDRESS] (S.J.) Hongxu Li  
College of Electrical Engineering and Information, Northeast Agricultural University, Harbin 150030, China; [EMAIL_ADDRESS] (K.S. ); [EMAIL_ADDRESS] (C.L. ); [EMAIL_ADDRESS] (Z.L. ); [EMAIL_ADDRESS] (H.L. ); [EMAIL_ADDRESS] (J.S. ); [EMAIL_ADDRESS] (S.J.) Hongxu Li  
College of Electrical Engineering and Information, Northeast Agricultural University, Harbin 150030, China; [EMAIL_ADDRESS] (K.S. ); [EMAIL_ADDRESS] (C.L. ); [EMAIL_ADDRESS] (Z.L. ); [EMAIL_ADDRESS] (H.L. ); [EMAIL_ADDRESS] (J.S. ); [EMAIL_ADDRESS] (S.J.) Hongxu Li  
College of Electrical Engineering and Information, Northeast Agricultural University, Harbin 150030, China; [EMAIL_ADDRESS] (K.S. ); [EMAIL_ADDRESS] (C.L. ); [EMAIL_ADDRESS] (Z.L. ); [EMAIL_ADDRESS] (H.L. ); [EMAIL_ADDRESS] (J.S. ); [EMAIL_ADDRESS] (S.J.) Hongxu Li  
College of Electrical Engineering and Information, Northeast Agricultural University, Harbin 150030, China; [EMAIL_ADDRESS] (K.S. ); [EMAIL_ADDRESS] (C.L. ); [EMAIL_ADDRESS] (Z.L. ); [EMAIL_ADDRESS] (H.L. ); [EMAIL_ADDRESS] (B.H.) Hongxu Li  
College of Electrical Engineering and Information, Northeast Agricultural University, Harbin 150030, China; [EMAIL_ADDRESS] (K.S. ); s221 requirements have driven the integration of UPQC with distributed energy resources (such as photovoltaic and wind energy) to realize multifunctional systems [5; 6]. Thus, to simultaneously address power-quality issues arising from both current and voltage, while also providing green energy support, UPQC remains one of the most effective solutions available. The choice of a suitable control strategy is crucial in determining the expected performance of any power electronic system. Consequently, the performance of the UPQC system largely depends on its control strategy. In the UPQC system, maintaining a stable DC-link voltage is crucial for the proper functioning of power converters and directly impacts overall system performance and power quality. The DC-link voltage acts as a buffer between the AC and DC sides of the system, and its stability is essential for effective voltage and current regulation. Various DC-link voltage control strategies have been proposed, each with distinct advantages and limitations. Traditional PI control methods are widely adopted for their simplicity and ease of implementation. However, their fixed-gain characteristics lead to compromised dynamic performance during sudden load changes or grid disturbances. Fuzzy logic controllers demonstrate superior adaptability to non-linear system conditions through rule-based decision-making but require significant computational resources and expert knowledge for membership function tuning. More recently, sliding mode control approaches have gained attention for their strong robustness against parameter variations, though they introduce undesirable voltage chattering that may increase switching losses. Any fluctuations or instability in the DC-link voltage can lead to poor load regulation, voltage sags, and harmonic distortion, degrading the overall system performance [7]. However, in some cases, a single control strategy is typically adopted, which may not ensure optimal steady-state and dynamic performance of the control system [8]. A data-driven control (DDC) approach focused on efficiency has been introduced to optimize the scale of the UPQC system. This approach is model-free and demonstrates notable robustness against parameter fluctuations. Nonetheless, it is relatively complex and less prevalent in engineering applications.