Nonlinear Control of a Two-Stage Single-Phase DC-AC Converter

In this article, a multi-input multi-output nonlinear control strategy for a two-stage single-phase dc-ac converter is introduced. The design technique is based on a multi-input multi-output feedback linearization strategy. A change of coordinates is used for obtaining a decoupled two-input two-output linear description. It allows us to design a linear controller in a transformed domain. Finally, this linear controller is expressed in original coordinates, resulting in the proposed nonlinear controller. Using this nonlinear controller allows improving the performance of the converter in presence of large excursions of reference and disturbance signals. The performance of the whole system is tested via simulation and experimental results using both linear and nonlinear loads.