Design and Implementation of a Novel Switched Rectifier Based Voltage Multiplexer for Multilevel Inverters

Abstract

In this study, a hybrid approach is presented for the asymmetric Cascaded H-Bridge (CHB) MLI topology. Two switches are added to the High Frequency Link (HFL) circuit to allow the HFL output voltage to vary between full and half levels. This modification rescales the DC bus voltages, allowing the system that traditionally produces 9 levels to produce a 15-level output voltage. Simulation studies are performed in Matlab/Simulink and PLECS and experimental verification is performed on an FPGA-based setup. The dynamic performance of the proposed topology is verified for stable operation under high inductive load (200 Omega + 200 mH) and over a wide frequency range (25-200 Hz). Compared to recent studies, the proposed design shows advantages in terms of component count, cost per level and total standing voltage (TSV). The Nearest Level Control (NLC) method is used for switching control, which optimizes the sinusoidal output quality with low switching losses (95.85 % efficiency). This method provides a cost-effective solution, increasing the number of levels of MLI topologies and enhancing their inductive load driving capability, making them suitable for industrial motor drives and renewable energy systems.