Asymmetrical Single-Phase Cascaded Differential Multilevel Inverter for PV Applications

A single phase cascaded structure of a multilevel inverter module is proposed in this paper. Apart from addition, it is able to do the differentiation of asymmetric voltage sources in the module itself. This unique feature enhances the levels of inverter output voltage with minimum voltage sources. Each module generates the single voltage polarity which then followed by an H-bridge to produce the dual polarities. The presented topology has the capability of performing with both symmetrical and asymmetrical sources. This topology is more preferable for solar PV applications where isolated sources are available. The simulation of the proposed basic module is carried out with PV source in MATLAB environment. Two cascaded structures of differential multilevel inverter (DMI) are considered for the analysis and experimental results. The experiment is carried out with R-L load and various dynamic conditions. Nearest Level Control (NLC) modulation is used as switching technique. MATLAB as well as experimental results shown are well validated according to the analysis of the topology.