Feedback Linearization Control for a Class of Transformerless Common-Ground VSI

Abstract

As is well known in practice, conventional transformerless inverters may suffer the risk of high-frequency leakage currents between the photovoltaic (PV) array or battery energy storage systems (BESS) and the ground due to the stray capacitances. This operational condition can generate several electrical problems. Recently, we proposed in [1] a new method for designing transformerless topologies of single-phase voltage source inverters (VSI) with common ground derived from four classical DC-DC converters. As a sequence of that previous work, a novel control technique based on a feedback linearization approach is proposed to control that class of transformerless VSI with common ground in this paper. Unlike the classical local linearization techniques commonly used in the technical literature, this approach allows to obtain large-signal linear equations, by means of the feedback linearization of the non-linear terms. Real-time simulation results using Hardware-in-the-Loop allow validation of the proposed discrete control technique applied to this class of VSI topologies.

Keywords

• Feedback linearization control
• Inverter topologies
• Leakage Current
• Transformerless inverter