A Single-Stage Multi-Port Buck-Boost Inverter

This article presents a novel inverter topology with a multi-port structure, which aims to connect two independent dc sources to a three-phase load by using single-stage power conversion. The proposed inverter has been developed to be used in hybrid renewable energy applications such as photovoltaic (PV), fuel cell (FC), and battery energy storage systems. Compared to the conventional hybrid dual-source inverters that use a multi-input dc-dc converter to provide a dc-link voltage at the input of the inverter stage, the proposed dual-source inverter uses an integrated dc-ac power conversion stage. The conventional topologies use bulky electrolytic capacitors at the input of the inverter stage, which leads to lower voltage gain and reliability due to high parasitic ESR/ESL and short lifetime of these capacitors. Moreover, compared to existing multi-port voltage source inverters, the proposed topology uses lower semiconductors, cost, and weight and has higher voltage gain. Besides, the proposed topology draws continuous current from both input ports and there is magnetic isolation between the input sources, which makes it suitable for hybrid PV and FC systems. In the proposed topology, two interlocked impedance networks are used, which are connected by coupled inductors, diodes, and capacitors. The proposed topology uses a simple switching method that is implemented with low-cost microcontrollers. The analysis and performance of the proposed inverter are verified through both computer simulations and experimental results of a 600 W-50 Hz laboratory prototype using the simple boost-SPWM modulation method.