This study discusses how to increase power quality by integrating a unified power quality conditioner (UPQC) with a grid-connected microgrid for clean and efficient power generation. An Artificial Neural Network (ANN) controller for a voltage source converter-based UPQC is proposed to minimize the system’s cost and complexity by eliminating mathematical operations such as a-b-c to d-q-0 translation and the need for costly controllers such as DSPs and FPGAs. In this study, nonlinear unbalanced loads and harmonic supply voltage are used to assess the performance of PV-battery-UPQC using an ANN-based controller. Problems with voltage, such as sag and swell, are also considered. This work uses an ANN control system trained with the Levenberg-Marquardt backpropagation technique to provide effective reference signals and maintain the required dc-link capacitor voltage. In MATLAB/Simulink software, simulations of PV-battery-UPQC employing SRF-based control and ANN-control approaches are performed. The findings revealed that the proposed approach performed better, as presented in this paper. Furthermore, the influence of synchronous reference frame (SRF) and ANN controller-based UPQC on supply currents and the dc-link capacitor voltage response is studied. To demonstrate the superiority of the suggested controller, a comparison of percent THD in load voltage and supply current utilizing SRF-based control and ANN control methods is shown.

Designing multi-terminal HVDC systems presents significant challenges, particularly in control, modeling, and protection. One of the most critical concerns is the protection of these systems from DC short circuits. DC circuit breakers (DCCBs) have traditionally been a key solution for handling fault conditions. However, as these systems scale up to meet increasing power demands, the associated cost and technical complexity of deploying DCCBs across large-scale systems make them less practical and economically viable. This has driven the exploration of alternative or supplementary strategies to address short circuits more cost-effectively. In this regard, fault current limiter (FCL) circuits combined with DC breakers have been proposed to reduce their demands. This paper presents an improved non-superconducting FCL circuit paired with a hybrid DC circuit breaker to enhance system performance. The proposed topology integrates power electronic (PE) bidirectional switches, current-limiting inductors, and a discharging resistor. Simulations have been conducted using PSCAD/EMTDC software. An equivalent circuit model based on the Zhoushan HVDC project is used for simulation analysis to study behavior under the influence of this breaker. In contrast to current approaches that utilize continuous current-limiting components, the proposed topology minimizes power loss during normal operation. The simulation results show robust current-limiting performance, quicker fault isolation, and reduced energy absorption by the breaker. With the proposed circuit, the fault clearing time is improved by 23%, and energy absorption performance is enhanced by 98%. Compared to the existing topology in the literature the proposed design demonstrates superior current limiting performance. The proposed FCL reduces the fault current to 2 kA whereas the literature reported topology limits it to 2.5 kA. Further, it achieves significantly lower energy absorption, measured at 0.12 MJ compared to 0.4 MJ in the literature. A comparative analysis with the existing methods from the literature demonstrates that the proposed FCL offers superior current-limiting capabilities, faster fault response, and lower power losses.