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Simulation and Real Time Implementation of Various PWM Strategies for 3 Φ Multilevel Inverter Using FPGA C. R. Balamurugan; S. P. Natarajan; T. S. Anandhi; B. Shanthi
International Journal of Reconfigurable and Embedded Systems (IJRES) Vol 6, No 1: March 2017
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1165.178 KB) | DOI: 10.11591/ijres.v6.i1.pp1-19


For high power applications Multilevel Inverter (MLI) is extensively used. The major advantages of MLI are good power quality, low switching losses and maintenance of the desired voltage. In this work, the three phase cascaded multi level inverter is analyzed under various modulation techniques that include Sub-Harmonic Pulse Width Modulation (SHPWM) i.e. Phase Disposition (PD) strategy, Phase Opposition Disposition (POD) strategy, Alternate Phase Opposition Disposition (APOD) strategy, hybrid strategy (PD and PS) and Phase Shift (PS) strategy. The study will help to choose those techniques with reduced harmonics for the chosen three phase cascaded MLI with R-L load. The Total Harmonic Distortion (THD), VRMS (fundamental), crest factor and form factor are evaluated for various modulation indices at two different switching frequencies (3.15KHz and 6 KHz). Simulation is performed using MATLAB-SIMULINK. It is observed that HYBRID PWM and PSPWM methods provide output with relatively low distortion for low and high switching frequencies. PODPWM and PSPWM are found to perform better since they provide relatively higher fundamental RMS output voltage for 6 KHz and 3.15 KHz switching frequencies. The experimental result shows PSPWM provide output with low distortion and HYBRID PWM provide output with higher fundamental RMS voltage for fc=3.15KHz. The experimental results were obtained only for fc=3.15KHz.
Analysis of Harmonics and Ripple Current in Multi-module Converters with Increasing Number of Modules for High Power Applications D. Venkatasubramanian; S. P. Natarajan
International Journal of Power Electronics and Drive Systems (IJPEDS) Vol 7, No 4: December 2016
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (355.705 KB) | DOI: 10.11591/ijpeds.v7.i4.pp1402-1409


Controlled rectifiers are considered as the most important hardware part in the field of HVDC systems in transmission lines and can be used for a number of power electronics based system operation, control and utility applications. In this paper, a brief design of a 12-pulse, 24-pulse, 36-pulse and a 48-pulse converter connected to the grid is presented along with the harmonic and ripple current analysis with its comparison statistics and thus providing a justification for the suitable ones. The performance of the 12, 24, 36 and 48-pulse converters are compared for their effectiveness in both quantitatively as well as qualitatively. Further, comparison of the 48-pulse converter on its THD and current ripple which is connected towards the grid with simple pulse width modulation technique is also proposed. It combines all features of the low switching concepts and DC current re-injection techniques. Some basic topological explanation of the controlled rectifiers and simulation results using MATLAB are also presented in this paper in order to justify the harmonic analysis. The simulation results along with the quantitative results shows the effectiveness of the proposed scheme for the cancelation or the elimination of the harmonics result in maximum harmonic mitigation, for high power utility applications, the 48-pulse converter is most fitting to improve the conversion efficiency, low di/dt and dv/dtand active and reactive power controllability.