Design and modeling of a transformerless hybrid inverter system using a fuel cell as energy storage element for microgrids with sensitive loads

The development of static power converters capable of transforming DC energy obtained from alternative sources into AC has become one of the main challenges in renewable energy systems. In this context, this paper presents a Stand-Alone Transformerless Hybrid Single-Stage Inverter that works with fully controlled waveforms of output voltage and input inductor currents. It also promotes high voltage gain without using a pre-regulator circuit, reducing the weight and size of the inverter structure. Preliminary experimental results are presented in order to prove the effectiveness of the proposed hybrid inverter in a stand-alone photovoltaic system. An intelligent energy-management control strategy has been developed for purpose of providing conditions for saving the auxiliary power source energy through the extraction of maximum power from the PV array. As a result, an autonomous energy system has been achieved since it provides reduced dependence on weather conditions, leading to a high reliability system.