An Envelope Type (E-Type) Module: Asymmetric Multilevel Inverters With Reduced Components

This paper presents a new E-type module for asymmetrical multilevel inverters (MLIs) with reduced components. Each module produces 13 levels with four unequal dc sources and 10 switches. The design of the proposed module makes some preferable features with a better quality than similar modules such as the low number of semiconductors and dc sources and low switching frequency. Also, this module is able to create a negative level without any additional circuit such as an H-bridge, which causes reduction of voltage stress on switches. Cascade connection of the proposed structure leads to a modular topology with more levels and higher voltages. Selective harmonics elimination pulse width modulation (SHE-PWM) scheme is used to achieve high-quality output voltage with lower harmonics. MATLAB simulations and practical results are presented to validate the proposed module good performance. Module output voltage satisfies harmonics standard (IEEE519) without any filter in output.