Umbría Jiménez, FranciscoGordillo Álvarez, FranciscoGómez‐Estern Aguilar, FabioSalas Gómez, FranciscoPortillo Guisado, Ramón CarlosVázquez Pérez, Sergio2015-03-052015-03-052014Umbría Jiménez, F., Gordillo Álvarez, F., Gómez‐Estern Aguilar, F., Salas Gómez, F., Portillo Guisado, R.C. y Vázquez Pérez, S. (2014). Voltage balancing in three-level neutral-point-clamped converters via Luenberger observer.0967-0661http://hdl.handle.net/11441/23372This paper addresses the problems associated with the dc-link capacitor voltages of the three-level neutral-point-clamped power converter: the imbalance of the capacitor voltages as well as the presence of an ac-voltage low-frequency oscillation in the dc link of the converter. In order to cope with them, a mathematical analysis of the capacitor voltage difference dynamics, based on a direct average continuous model, is carried out, considering a singular perturbation approach. The analysis leads to a final expression where a sinusoidal disturbance appears explicitly. Consequently, the two problems can be handled together using the ordinary formulation of a problem of regulating the output of a system subject to sinusoidal disturbances, applying classical control theory to design the controller. In this way, the controller is designed including the disturbance estimate provided by a Luenberger observer to asymptotically cancel the disturbance, while keeping also balanced the capacitor voltages. Experiments for a synchronous three-level neutral-point-clamped converter prototype are carried out to evaluate the performance and usefulness of the converter working as a grid-connected inverter under the proposed control law.application/pdfengAtribución-NoComercial-CompartirIgual 4.0 Internacionalhttp://creativecommons.org/licenses/by-nc-sa/4.0/Multilevel power converterneutral-point-clamped (NPC) convertervoltage balancingdisturbance rejectionLuenberger observerinfo:eu-repo/semantics/articleinfo:eu-repo/semantics/openAccesshttps://doi.org/10.1016/j.conengprac.2013.12.003