Cascaded half-full-bridge PWM multilevel inverter configuration

Authors: CHARLES IKECHUKWU ODEH

Abstract: inverter topology. It is made up of a main inverting H-bridge legs and level-clamping half-bridge circuits, each having its own dc source. The single-carrier, multilevel PWM scheme is employed to generate gating signals for the power switches. The modulation scheme is hybridized to enable the output voltage of the proposed inverter configuration to inherit the features of switching-loss reduction from fundamental PWM and good harmonic performance from multiple sinusoidal PWM. Moreover, a simple base PWM circulation scheme is also introduced in this work to obtain a resultant sequential switching hybrid PWM (SSHPWM) circulation that balances power dissipation among the four power switches of the main H-bridge module. Operational principles with switching functions are given. For a modulation index of 0.9, the proposed inverter configuration was subjected to an R-L load and the respective numbers of output voltage level were synthesized. FFT analyses of the output voltage waveforms were carried out and the corresponding THD value of 13.16{\%} was obtained. To verify the performance of the proposed inverter architecture, simulations and experiments were carried out on a 2.95 kW rated prototype of the proposed inverter for an R-L load and adequate results were obtained.

Keywords: Inverter, multilevel, PWM, H-bridge, cascade

Full Text: PDF