POWER QUALITY ENCHANCEMENT

This book deals with new nonlinear current control strategy based on backstepping control and high-order sliding mode differentiator in order to employ distributed generation unit interfacing converter to actively compensate harmonics/interharmonics of local loads. The converter-based DG unit is connected to a weak grid and local load through an LCL filter. The strategy robustly regulates the inverter output currents and delivers pure sinusoidal three-phase balanced currents to the grid. The new controller demonstrates the robust performance and robust stability of the DG unit system with respect to the filter parameters uncertainties grid impedance grid frequency and grid voltage as well as the unknown load dynamics that include unbalanced loads and nonlinear loads with harmonics and interharmonics currents. We should remark that the local compensation of the loads with interharmonics current using a DG unit system.