High-Frequency Link Voltage Multiplexing for Multi-Level Inverters with Optimized Transformer Windings

The need for more than one voltage source in multilevel inverters (MLI) increases the system cost and circuit complexity. In this study, a voltage multiplexing method with a high frequency link (HFL) structure is proposed as a solution to the problem in question. Unlike the traditional HFL application, a half H -bridge is added to the input of the transformer and thus the obtained voltage is diversified. The output voltage is provided by a separate H-bridge circuit by preserving the isolation of the input and output voltages. The winding ratios of the transformer are determined by optimizing the total harmonic distortion (THD) of the output voltage with the NLC method. The proposed topology provides a low THD value of $\mathbf{1 1. 7 3 \%}$ despite different voltage steps. In addition, simulations performed under various amplitude and frequency conditions using the SPWM technique have shown that the proposed method is effective and applicable.