A Single Source Transformer-less Boost Multilevel Inverter Topology with Self Voltage Balancing

Abstract

In this article, a single source transformer-less boost multilevel inverter topology is proposed. The salient features of the proposed topology include voltage boost capability, reduced number of switches, and requirement of a single dc voltage source, which in turn reduces the overall cost and complexity. The proposed topology comprises a conventional boost converter and a diode–capacitor voltage multiplier circuit (VMC). The capacitors’ voltages of the VMC are self-balanced, which eliminates the requirement of any auxiliary circuit for capacitor voltage balancing. Moreover, due to the input inductor, it has less input current ripple and able to provide variable fractional voltage gain, which is a key requirement for maximum power point tracking in photovoltaic applications. In order to get an optimal harmonic profile of the output ac voltage, a fundamental frequency switching technique named as the fundamental frequency sine quantization method is adopted for the generation of the switching signals. Finally, a hardware prototype of the proposed 11-level boost inverter is developed and the experimental results along with the MATLAB/Simulink results are presented to validate the efficacy of the proposed converter.