Recent Advances in Power Quality Analysis and Robust Control of Renewable Energy Sources in Power Grids

The growing share of renewable energy sources in electricity grids poses a challenge in maintaining power quality due to the variability of generation and the resulting disturbances such as voltage sags, harmonic distortions, frequency deviations and imbalances. Overcoming these problems requires advanced power electronic converters, energy storage systems such as supercapacitors and sophisticated control strategies. Microgrids that integrate RES, storage and loads offer flexible operation in both grid-connected and islanded modes. This Special Issue presents the latest advances in improving grid quality and renewable energy control. Topics include power factor correction for unbalanced and distorted loads, modeling and parameter identification of supercapacitors using hybrid optimization, and novel pulse width modulation techniques to reduce switching losses and improve inverter efficiency. Furthermore, the detection of disturbances using wavelet transforms and neural convolutional networks, as well as the analysis of motor vibrations under distorted voltage conditions, are covered. Control strategies, such as backstepping for neutral-point clamped inverters, enable the reduction of harmonics and the equalization of the DC link voltage. Hierarchical and distributed voltage control using phasor measurement devices improves coordination and reduces constraints in distribution grids. In addition, optimization algorithms such as the Gray Wolf Optimizer are used to tune the parameters of PI controllers in multiphase motor drives for better speed stability.