Line-to-line Voltage Space Vector Modulation for Neutral-point Clamped Multi-level Converter with DC-link Capacitor Voltage Balancing Using Redundant Vectors

Abstract

This article presents space vector modulation of line-to-line voltage for the three-phase neutral-point clamped n-level converter with DC-link capacitor voltage balancing using redundant vectors. The developed modulation strategy is based on an equivalent matrix structure of the neutral-point clamped n-level converter. The relation between the 3 × (n – 1) switching functions of the matrix converter and gate signals of transistors of the neutral-point clamped n-level converter is given. A line-to-line space vector modulation strategy for a matrix inverter is used to obtain the switching function. For one switching function, there is more than one combination to produce each output voltage. Thus, redundancies of different switch configurations for generation of intermediate voltages are used to limit the deviation of capacitor voltages. The gate signals of the neutral-point clamped n-level converter can be calculated by inversing the modeling parts. Here, line-to-line voltage space vector modulation for a neutral-point clamped n-level converter is designed without using a Parks transform. Moreover, n × (n – 1) redundant vectors are used for DC bus voltage balancing. To highlight the performances of the developed modulation strategy, simulation results are given for five- and seven-level neutral-point clamped converters. Experimental results are given for a neutral-point clamped three-level converter.

Keywords:

• neutral-point clamped voltage source inverter
• converter modeling
• matrix converter
• line-to-line space vector modulation
• DC bus voltage balancing

Additional information

Notes on contributors

Omar Bouhali

Omar Bouhali was born in Chekfa, Algeria, 1974. He received the engineer degree and the master degree in automatic from national polytechnic school of Algeria, in 1996 and 1998 respectively. He received the Ph. D. degree from the Central School of Lille, France and National Polytechnic School of Algeria in 2007. Since 1998, he has been a lecturer in the automatic department of Jijel University, Algeria. And he is a director of Jijel Mecatronic Laboratory (LMT) and Vice Rector in charge of External Relations, Cooperation, entertainment and communication and Scientific Events of Jijel University. He is working in the development of renewable energy based power systems with storage using multilevel converters.

Bruno Francois

Bruno Francois was born in St Amand les Eaux, France, in 1969. He received the Ph. D. degree from the University of Lille, France in 1996 and his HDR “Habilitate to supervise research” in 2003. He is Professor at the Electrical Engineering department of Ecole Centrale de Lille. He is a member of Laboratory of Electrical Engineering (L2EP), Lille. He is currently working on the design of modulation and control systems for multilevel converters and also the development of renewable energy based power systems.

Nassim Rizoug

Nassim Rizoug received the Engineering degree from the E.N.P. (Ecole Polytechnique d’Alger), Algeria in 1998 and the Ph. D. in Electrical Engineering from the Ecole Centrale de Lille, France, in 2006. He is currently Assistant Professor at the Ecole Supérieure des Techniques Aéronautiques et de Construction Automobile (ESTACA), France since 2007. His research interest includes specially the field of energy management and the characterization of the storage component for the power electronic applications.