Proposed in this article is bidirectional real and reactive power control of a three-phase grid-connected inverter under unbalanced grid conditions using a proportional-resonance controller. Different unbalanced grid conditions have been studied, such as unbalanced three-phase load and unbalanced grid impedance. These unbalanced scenarios generate unbalanced grid currents and unbalanced point-of-common-coupling (PCC) voltages, causing large oscillations in both real and reactive power transferred to the grid. The purposes of the suggested technique are to balance the grid currents and point-of-common-coupling voltages as well as control the power injected into the grid. As a result, balanced PCC voltages are guaranteed, the oscillation in real and reactive power is reduced, and power control is achieved. The proposed method’s performance has been verified in MATLAB/SIMULINK simulation software, and different experimental results have been obtained using a real-time interface platform, dSPACE DS1202.

Presented in this paper is a method of bidirectional real and reactive power control of a three-phase grid-connected inverter under unbalanced grid situations. Unbalanced three-phase load and unbalanced grid impedance are illustrations of unbalanced grid issues that have been investigated. As a result, both grid currents and point-of-common-coupling (PCC) voltages will be unbalanced. The real and reactive power that is delivered to the grid oscillates by a significant amount in these unbalanced conditions. A time-domain symmetrical components extraction approach is used to calculate the inverter’s reference currents from the negative- and zero-sequence components of the measured currents. The suggested approach corrects unbalanced grid currents and unbalanced PCC voltages, and provides the desired real and reactive power to the grid when unbalanced situations exist. As a consequence, power oscillations will be eliminated, and power control will be possible. The suggested method’s performance is supported by simulation, and various experimental results are obtained utilizing the dSPACE DS1202 real-time interface platform.

This article introduces a frequency-adaptive control strategy for a three-phase shunt active power filter, aimed at improving energy efficiency and ensuring high power quality in consumer-oriented power systems. The proposed control system utilizes real-time frequency estimation to dynamically adjust the gain of a proportional-integral–resonant (PIR) controller, facilitating precise harmonic compensation under challenging unbalanced grid conditions, such as unbalanced three-phase loads, grid impedance variations, and diverse nonlinear loads like three-phase rectifiers and induction motors. These scenarios often increase total harmonic distortion (THD) at the point of common coupling (PCC), degrading the performance of connected loads and reducing the efficiency of induction motors. The PIR controller integrates both proportional-integral (PI) and proportional-resonant (PR) control features, achieving improved stability and reduced overshoot. A novel voltage sensorless control method is proposed, requiring only current measurements to determine reference currents for the inverter, thereby simplifying the implementation. Validation of the frequency adaptive control scheme through MATLAB/Simulink simulations and real-time experiments on a dSPACE (DS1202) platform demonstrates significant improvements in harmonic compensation, energy efficiency, and system stability across varying grid frequencies. This approach offers a robust consumer-oriented solution for managing power quality, positioning the SAPF as a key technology for advancing sustainable energy management in smart applications.

Grid-connected voltage-source inverters (VSIs) have evolved over the past years for the interconnection of renewable energy sources with the grid to satisfy the increased electrical load demand and utilize clean carbon-free energy. However, VSIs suffer a significant drawback of switching harmonics caused by the inverter switches. To reduce the amount of current distortion injected into the utility grid and meet harmonic constraints as defined by power quality standards, an LCL filter is often used. Although extensive literature describes assorted design procedures for an LCL filter, all these methods cannot guarantee an optimal solution, because no direct mathematical function between the LCL filter parameters and the total harmonic distortion (THD) exists. Presented in this paper is the application of an evolutionary annealing–simplex method to select the inductance values in the LCL filter. This method is compared to other methods previously presented in the literature: a systematic method and an inductance grid-search method based on a calculated distribution of total harmonic distortion for various inductance values. The goal is to select the smallest overall inductance values to ensure lower manufacturing costs while maintaining the filter performance. Simulation and experimental results verify that at least a 40% reduction in overall inductance can be achieved with the proposed method while simultaneously guaranteeing the filtering performance.