Improved control strategy for power quality enhancement in standalone systems based on four‐leg voltage source inverters

Abstract

Standalone power supplies using renewable energy resources become a key solution to address both energy consumption and environmental restrictions in remote locations. These standalone systems are weak low‐voltage networks, wherein the presence of heavy non‐linear and/or unbalanced loads may adversely affect the output voltage quality. Accordingly, four‐leg voltage‐source inverters play an important role by providing both balanced and unbalanced loads with clean power and balanced output voltage. The reported work proposes a sliding mode control (SMC) along with an iterative learning control (ILC) for harmonic compensation in the presence of critical load conditions such as unbalanced non‐linear loads. Indeed, under substantial disturbances, the ILC harmonic compensator smoothly adjusts the input control signal of the SM controller in such a manner to properly reject the disturbing harmonics. The design methodology of the proposed SMC–ILC control scheme is detailed and its effectiveness is validated through simulation and experimental results.