Novel transformeless single-stage 4-switches Buck-Boost Inverter

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 novel topology of step-up/step-down single-stage DC-AC converter 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 or a transformer, reducing the weight and size of the proposed inverter structure. Preliminary simulation analysis is presented in order to prove the effectiveness of the single-stage inverter to be applied in stand-alone photovoltaic or fuel cell systems. Experimental results are included for a 300 W prototype, as well as a full discussion concerning the DSP implementation of the proposed PWM control technique.