An effective control method for three-phase quasi-Z-source cascaded multilevel inverter based grid-tie photovoltaic power system

Yushan Liu, Baoming Ge, Haitham Abu-Rub, Fang Zheng Peng

Research output: Contribution to journalArticle

74 Citations (Scopus)


The quasi-Z-source cascaded multilevel inverter (qZS-CMI) presented many advantages over conventional CMI when applied in photovoltaic (PV) power systems. For example, qZS-CMI provides the balanced dc-link voltage and voltage boost ability, saves one-third modules, etc. However, current research studies only disclosed control of single-phase qZS-CMI-based PV power systems, and there was no literature related to control of three-phase qZS-CMI-based PV power systems. In this paper, for the first time, three-phase qZS-CMI's control is proposed and demonstrated for application to PV power systems. The models of PV-panel-fed qZS H-bridge module and qZS-CMI-based PV power system are built to accurately design control algorithms for each module and the whole system. The proposed control method includes the distributed maximum power point tracking for each module, dc-link peak voltage balance control for all modules, and grid-tie control for the whole system; moreover, a new multilevel space vector modulation method is proposed for the three-phase qZS-CMI. Simulation and experimental results on a test bench with a three-phase seven-level qZS-CMI-based PV power system verify the proposed control and modulation methods.

Original languageEnglish
Article number6786003
Pages (from-to)6794-6802
Number of pages9
JournalIEEE Transactions on Industrial Electronics
Issue number12
Publication statusPublished - 1 Dec 2014



  • Cascaded multilevel inverter (CMI)
  • photovoltaic (PV) power systems
  • quasi-Z-source inverter
  • space vector modulation (SVM)

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Computer Science Applications
  • Electrical and Electronic Engineering

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