New Single-Stage Single-Phase Three-Input DC-AC Boost Converter for Stand-Alone Hybrid PV/FC/UC Systems

Abstract

This paper presents a new single-stage single-phase three-input DC-AC boost converter for stand-alone hybrid PV/FC/UC systems. The proposed converter enjoys a non-isolated single power conversion stage, which interfaces two unidirectional input ports for PV and FC sources and two bidirectional ports for UC and resistive load. It only needs six power switches and can directly step-up the low level input dc voltages into a high level output sinusoidal voltage without needing any output filtration stage. In fact, the proposed strategy presents a structure consisting of four dc boost converters, which are actively controlled in order to produce two output dc-biased sinusoidal voltages across the load. In this way, MPPT of the PV source, regulating the FC power and autonomous charging/discharging of the UC are accessible, while a pure sinusoidal voltage is generated at the output port. Moreover, regarding the maximum available PV power and the demanded load power a useful power management control scheme is proposed to exploit the FC and UC in their optimal operating points. Due to the multi-input multi-output (MIMO) inherent aspect of the proposed converter, pole-placement control strategy is applied to the proposed converter. The validity and effectiveness of the proposed converter and its control performance are verified by simulation and experimental results under different operating conditions.