Balancing Switching Losses in Three-phase, Five-level Pulse-width Modulation Switched Voltage Source Inverter Using Hybrid Modulation Techniques

Abstract

This article proposes a new switching strategy for a three-phase, five-level switched voltage source inverter. The single-carrier, multi-level pulse-width modulation (PWM) scheme is employed to generate gating signals for the power switches. The proposed modulation scheme is hybridized to enable the output voltage of the inverter configuration, inheriting the features of switching-loss reduction from fundamental PWM and good harmonic performance from multiple sinusoidal PWM. A sequential switching scheme is embedded with the already-employed hybrid modulation to overcome unequal switching losses and, therefore, differential heating among the power devices. Operational principles with switching functions are given. For an R-L load, Fast Fourier Transform (FFT) analyses of the output voltage waveforms were carried out, and the corresponding total harmonic distortion value of 26.09% was obtained. To verify the performance of the proposed modulation scheme, simulations and experiments are conducted on a 1.2-kW rated prototype of the inverter; adequate results are presented.

Keywords:

• inverter
• multilevel
• cascaded
• PWM
• H-bridge
• total harmonic distortion

Additional information

Notes on contributors

Charles Ikechukwu Odeh

Charles Ikechukwu Odeh received the B.Eng., M.Eng. and the Ph.D. degrees in electrical engineering from the Department of Electrical Engineering, University of Nigeria, Nsukka in 2002, 2006 and 2010, respectively. In between January through September 2011, he was an exchange scholar, sponsored by the United States Navy, at Tennessee Technological University, Cookeville, USA. He is currently lecturing at the Department of Electrical Engineering, University of Nigeria, Nsukka. His research interests are in the power electronics multilevel converter topologies and applications.