Four-level quasi-nested inverter topology for single-phase applications

Carlos A. Reusser, Hector Young

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


In this paper, a novel four-level single-phase multilevel converter is introduced, consisting of six active switches arranged in a quasi-nested configuration. The proposed topology synthesizes its output voltage levels with respect to a floating neutral point, using four cascaded capacitors with identical voltage levels. The proposed converter contains a reduced number of components compared to the neutral point clamped (NPC) or active-NPC topologies (ANPC) for the same number of output voltage levels, since it does not require diode or active switch clamping to a neutral point. Moreover, no floating capacitors with asymmetric voltage levels are employed, thereby simplifying the capacitor voltage balancing. The switching operation principles, modulation technique and control scheme for supplying a single-phase resistive-inductive load are addressed in detail. The proposed four-level inverter allows generating an additional output voltage level with the same semiconductor count as conventional three-level inverters such as NPC and ANPC which allows a superior waveform quality, with a THDv reduction of 32.69% in comparison the clamped inverters. Experimental tests carried out in a laboratory-scale setup verify the feasibility of the proposed topology.

Original languageEnglish
Article number233
Pages (from-to)1-19
Number of pages19
JournalElectronics (Switzerland)
Issue number3
StatePublished - 1 Feb 2021


  • DC-link voltage self-balancing
  • Levelshifted PWM
  • Multilevel inverter
  • Proportional multi resonant controller
  • Quasi-Nested topology
  • Reduced active switches topology
  • Single-phase applications


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