CASCADE TOPOLOGIES FOR THE ASYMMETRIC MULTILEVEL INVERTER BY NEW MODULE TO ACHIEVE MAXIMUM NUMBER OF LEVELS

Multilevel inverters have been introduced as useful devices to connect between DC-AC systems. Their high quality output and costs benefit a wide range of applications. Asymmetric multilevel inverters are a type of multilevel inverter with an unequal DC link to create more voltage levels through fewer components. This paper presents new topologies of cascade multilevel inverters by a new module with reduced components. The base module produces 13 levels with two types of unequal DC sources and 10 switches. Modular can be used to produce more and higher voltages levels. The designing of proposed multilevel inverter makes some preferable index with better quality than similar modular multilevel inverters, such as less semiconductors and DC sources, low switching frequency, creating of negative levels without any additional circuit, and module in cascade connections. Also, two cascade topologies are presented in the modular connections of the proposed module to achieve high and significant number of levels. Nearest level control (NLC) method as a switching technique is used in step changing levels for topologies to get more quality and lower harmonics. The presented module and cascade topologies are simulated by MATLAB/Simulink and are implemented by the experimental prototype in laboratory to validate the performance of proposed topologies in which simulated and experimental results show a good performance. THD% (Total Harmonic Distortion) of the module and cascade topology in experimental results calculated 4.94% and 2.05% respectively that satisfy harmonics standard (IEEE519).