Modelling and Controller Design for Y-Source Inverter Applied in Stand-Alone PV System

Abstract

The impedance source network inverters have interesting operational advantages over conventional inverters, allowing flexible operation as step-up/step-down converters, without the need to avoid simultaneous conduction of power switches located at the same inverter leg. In this context, inverters based on Y -type impedance networks have convenient features which solve several issues related to photovoltaic (PV) applications. Nevertheless, the non- minimum phase characteristics of such converter makes the control design complex. Therefore, this paper presents a complete modelling and control methodology which allows the integration of the Y-Source inverter (YSI) in a stand-alone single-phase photovoltaic generation application. The small-signal model for YSI is presented in detail together with design methodologies for the DC and AC side controllers. Moreover, the proposed control schemes were validated with computer simulations considering the Y -source inverter feeding both linear and non-linear loads.