Luís, RicardoSilva, José FernandoQuadrado, José Carlos2017-12-072017-12-072017-04LUÍS, Ricardo; SILVA, José Fernando; QUADRADO, José Carlos - Output voltage quality evaluation of stand-alone four-leg inverters using linear and non-linear controllers. Energies. ISSN 1996-1073. Vol. 10, N.º 4 (2017), pp. 1-201996-1073http://hdl.handle.net/10400.21/7667This paper presents the design and experimental voltage quality evaluation of controllers for the output voltages of 3-phase four-leg voltage source inverters. These inverters are needed in stand-alone power systems to supply linear and non-linear, balanced or unbalanced loads with constant RMS value voltages at fixed frequency. Comparisons include closed loop outer voltage controllers based on predictive, sliding mode and decoupled proportional-integral controllers in dqo synchronous space, fitted with an inner hysteretic current loop vector controller in alpha beta gamma space. The 3-phase four-leg VSI output voltages waveform quality is analysed under unbalanced and non-linear loads.engStand-alone four-leg inverterNon-linear voltage vector modulatorVoltage waveform qualityjournal article10.3390/en10040504