Assessment of a Reconstructed Modulation Strategy for Energy Balance in Multilevel Cascade Inverters Varying the Modulation Index

ABSTRACT This paper presents an experimental evaluation of a PWM modulation strategy based on reconstructed modulators applied to a seven‐level cascaded multilevel inverter. The proposed approach aims to achieve effective energy balance among inverter cells while maintaining high output voltage quality and low digital implementation cost by shifting the balancing mechanism from the carrier level to the modulation stage through the reconstruction of sinusoidal modulating signals. The performance of the strategy is analyzed under variations of the modulation index, considering key performance indicators such as total harmonic distortion, weighted total harmonic distortion, power imbalance among inverter cells, and FPGA resource utilization. Experimental results demonstrate that optimal performance is achieved at a modulation index of m = 0.9, where THD and WTHD values of 1.34% and 1.05% are obtained, respectively, while the maximum power imbalance among cells remains below 1%, reaching 0.64%. A comparative evaluation with level‐shifted PWM strategies confirms that the proposed approach provides improved harmonic performance and significantly reduced digital resource usage, requiring only 11% of the available FPGA resources. These results highlight the effectiveness of the reconstructed modulators strategy as a practical and efficient solution for cascaded multilevel inverters in photovoltaic and other energy conversion applications.