An Envelope Type (E-Type) Module Asymmetric Multilevel Inverters With Reduced Components Renewable Energy and Systems Projects


This paper presents a new E-Type module for asymmetrical multilevel inverters 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.


  1. Asymmetric
  2. Components
  3. E-Type
  4. Multilevel inverter
  5. Power electronics
  6. Selective harmonics elimination





Fig. 1 Proposed E-Type module of multilevel inverter (a) Circuit topology 



 Fig.2 Output voltage and FFT analysis of proposed multilevel


This paper presented a new multilevel inverter topology named as Envelope Type (E-Type) module which can generate 13 levels with reduced components. It can be used in high voltage high power applications with unequal DC sources. As E-Type module can be easily modularized, it can be used in cascade arrangements to form high voltage outputs with low stress on semiconductors and lowering the number of devices. Modular connection of these modules leads to achieve more voltage levels with different possible paths. It causes an improvement in the reliability of the modular inverter which enables it to use different paths in case of malfunction for a switch or a driver. The main advantage of proposed module is its ability to generate both positive and negative output voltage without any H-bridge circuit at the output of the inverter. THDv% is obtained 3.46% and 4.54% in simulation and experimental results, respectively that satisfy harmonics standard (IEEE519). Also module is tested in three frequency and under different resistive – inductive loads which results shows good performance.


[1] R. Feldman, M. Tomasini, E. Amankwah, J.C. Clare, P.W. Wheeler, D.R. Trainer, R.S. Whitehouse, “A Hybrid Modular Multilevel Voltage Source Converter for HVDC Power Transmission,” IEEE Trans. Ind. Appl., vol.49, no.4, pp.1577–1588, July-Aug. 2013.

[2] M. Odavic, V. Biagini, M. Sumner, P. Zanchetta, M. Degano, “Low Carrier–Fundamental Frequency Ratio PWM for Multilevel Active Shunt Power Filters for Aerospace Applications,” IEEE Trans. Ind. Appl., vol.49, no.1, pp.159–167, Jan.-Feb. 2013.

[3] Liming Liu, Hui Li, Seon-Hwan Hwang, Jang-Mok Kim, “An Energy-Efficient Motor Drive With Autonomous Power Regenerative Control System Based on Cascaded Multilevel Inverters and Segmented Energy Storage,” IEEE Trans. Ind. Appl., vol.49, no.1, pp.178–188, Jan.-Feb. 2013.

[4] Yushan Liu, Baoming Ge, H. Abu-Rub, F.Z. Peng, “An Effective Control Method for Quasi-Z-Source Cascade Multilevel Inverter-Based Grid-Tie Single-Phase Photovoltaic Power System,” IEEE Trans. Ind. Inform., vol.10, no.1, pp.399–407, Feb. 2014.

[5] Jun Mei, Bailu Xiao, Ke Shen, L.M. Tolbert, Jian Yong Zheng, “Modular Multilevel Inverter with New Modulation Method and Its Application to Photovoltaic Grid-Connected Generator,” IEEE Trans. on Power Electron., vol.28, no.11, pp.5063–5073, Nov. 2013.


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