Abstract
This article presents a carrier-based pulse-width modulation (PWM) template for a 5-level, H bridge-based cascaded multilevel inverter (MLI). The developed control concept generates adequate modulation template for this inverter topology wherein a sinusoidal modulating waveform is modified to fit in a single triangular carrier signal range. With this modulation approach, classical multiplicity and synchronization of the triangular carrier signals criterion for the extension of sinusoidal pulse-width modulation, SPWM, to several cascaded 5-level, H-bridge-based MLI topology are removed. The proposed template can be used on the inverter configuration of any level with no further control modification. Nearly even distribution of switching pulses and equalized individual cascaded cell output power were achieved with the proposed modulation scheme. Three 5-level, H-bridge-based MLI units were cascaded for 1-phase, 13-level inverter operation; simulation and experimental results are adequately presented.
Highlights
Dc to ac converters are essential power electronics components used in many important areas such as high-voltage direct-current (HVDC) transmission [2,3], Flexible AC Transmission Systems (FACTS) [4,5], renewable energy grid integration [6,7], railway and vehicle traction [8,9], energy storage systems [10], marine propulsion [11], etc
Both are modified traditional inphase disposition and phase-shifted SPWM techniques wherein rectified modulating signal is used to reduce the number of triangular carrier waves
The two-fold advantage of this SPWM approach is: first, the single triangular carrier wave used in creating the MWT is insensitive to the number of cascaded inverter units, as detailed earlier in Figure 3; secondly, the input split capacitor bank voltages can be controlled since their dynamic value variations can be optional inputs while referring to the modulation template
Summary
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. MLI power circuit configurations have been the dominant research topic in the literature [13,14], as a reflection of the innate capabilities of this type of inverters and their influences on many industrial applications These newly evolved MLI configurations have their operational concepts from those of the traditional MLIs: cascaded H- bridge (CHB), diode-clamped and capacitor-clamped (flying capacitor) multilevel inverters. Most used configurations of the diode-clamped and capacitor-clamped multilevel inverters have been restricted to the synthesis of three-level output voltage waveforms because of input voltage deviations. These 3-level inverter configurations have reached industrial maturity and are mass-produced to serve needs of varying degrees.
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