Multilevel, one-phase inverter with unequal voltage distribution

Purpose - The purpose of this paper is to introduce a unique multilevel, one-phase inverter (in the multiplied full-bridge configuration, cascaded-type) with unequal voltage distribution among the voltage levels.Design methodology approach - Numerical and experimental results are discussed and the topology thereafter evaluated.Findings - Unequal voltage distribution among voltage stages of the converter leads to increase of the output voltage resolution while simplifying the converter construction and minimizing the power switch losses. Simplorer numerical analyses as well as test stand measurements were led in order to verify properties of the system. Using the voltage distribution in the proportion of 6 2 1 leads to improved utilisation of power switches used in the means of voltage, current and switching frequency. FFT analysis was implemented in order to explore the frequency domain properties of the control apparatus.Practical implications - The results allow improvement of power switch utilisation and output voltage resolution of cascaded, three-stage multilevel converter topologies and voltage output filter optimisation for multilevel power electronic converters.Originality value - A new concept of voltage distribution is provided and described, a dedicated DSP-based control system was developed as well as a small-scale converter prototype, test stand measurement results are provided.