International Journal of Modern Engineering Research (IJMER) www.ijmer.com Vol.3, Issue.1, Jan-Feb. 2013 pp-204-211 ISSN: 2249-6645 www.ijmer.com 204 | Page V. Arun, 1 B.Shanthi, 2 S. P. Natarajan 3 1 Department of EEE, Arunai Engineering College, Thiruvannamalai, Tamilnadu, India 2 Centralised Instrumentation and Service Laboratory, Annamalai University, Chidambaram, Tamilnadu, India 3 Department of EIE, Annamalai University, Chidambaram, Tamilnadu, India ABSTRACT: This paper presents multicarrier PWM strategies for three phase cascaded seven level Z-source inverter. Multilevel inverters posses the advantage of reduced harmonics, high-power capability and high-voltage level. Impedance network in the cascaded multilevel inverter circuit will perform boost operation. This paper focuses on multicarrier sinusoidal pulse width modulation (MCSPWM) strategy for the three phase seven level Z source cascaded inverter. Performance parameters of three phase seven level Z source cascaded inverter have been analyzed. A simulation model of three phase seven level Z source cascaded inverter developed using MATLAB/SIMULINK and its performance has been analyzed. Keywords: APOD, CO, POD, PD, SPWM. I. INTRODUCTION Multilevel inverters have become an attractive choice as a partial solution to the improvement of the global conversion chain efficiency. Multilevel inverter is a switching converter where the appropriate control of an arrangement of switching devices allows combining diverse input voltages to synthesize a sinusoidal output voltage waveform. Carrara et al [1] discussed various multilevel PWM methods and theoretical analysis of PWM strategies. Huang et al [2] proposed Z- source inverter for residential photovoltaic applications. Loh et al [3] have used pulse-width modulated strategies for Z- source neutral point clamped inverter. Various pulse-width modulated strategies for Z source inverter was discussed by Loh et al [4]. Different control strategies for Z-source neutral-point-clamped Inverter and also for cascaded MLI were discussed in [5,6]. Malinowski et al [7] analysed various cascaded multilevel inverters. Three level Z source inverter topology was introduced by Peng in [8]. Rendusara et al [9] analysed common mode voltage and PWM strategies for adjustable speed drive. Shanthi and Natarajan [10] discussed various unipolar PWM strategies for single phase five level cascaded inverter. Zhou et al [11] discussed Z source inverter based single phase uninterruptible power supply. II. Z-SOURCE SEVEN LEVEL CASCADED INVERTER Figure1 shows the two-port network that consists of an inductors (L1, L2) and capacitors (C1, C2) and connected in X shape is employed to provide an impedance source (Z Source) coupling the inverter to the dc source. Figure 1 Impedance Network Performance Analysis of Multicarrier SPWM Strategies for Three Phase Z - Source Seven Level Cascaded Inverter