A Hybrid Pulse Width Modulation Strategy for Dual Bridge Multilevel DC-Link Inverter

摘要

The paper attempts to formulate a pulse width modulation (PWM) strategy suitable to operate the switches at high frequency in the dual bridge multilevel dc link inverter (MLDCI). It follows the theory of sub harmonic pulse width modulation (SHPWM) to involve a direct comparison between the sinusoidal reference and several stacked high frequency triangular waveforms. It charters to create a negative cycle inversion (NCI-HPWM) based single reference and avail the phenomenon of single carrier modulation strategy to pronounce a better synthesis of the output waveform. It forges to outline the locus for fundamental switching of the lower part of the power module in an effort to ensure it remains within the boundaries of the operating region. The scheme investigates using Mat lab based simulation the proposed NCI-HPWM methodology for an 11- level inverter, and establishes its benefits in terms of the frequency spectrum. It includes detailed FPGA based experimental waveforms to orchestrate the feasibility of the mechanism for use in practical circuits.