A new single-phase PV fed five-level inverter topology connected to the grid

There is a strong trend in the photovoltaic (PV) inverter technology to use transformerless topologies in order to acquire higher efficiencies. This paper presents a single-phase five-level grid connected PV inverter with a novel dual reference modulation technique. Two reference signals identical to each other with an offset equivalent to the amplitude of the rectified inverted sine carrier signal were used to generate PWM signals. The inverter consists of a full-bridge inverter and an auxiliary circuit comprising four diodes and a switch. The inverter produces output voltage in five levels: zero, +1/2 V_dc, V_dc, -1/2 V_dc and -V_dc. The validity of the proposed inverter is verified through simulation.