A Single-Phase 35-levels Cascaded PUC Multilevel Inverter Fed by a Single DC-Source

This work proposes a new multilevel inverter topology composed of a PUC5 and an MPUC7 convert cascaded connected fed by only one dc power source by using a high-frequency link. This topology can provide 35-level voltage by using four asymmetrical dc-links, and only twelve power switches. The second dc-link operates as a floating capacitor, while the two smaller dc-links are supplied by the dc-source through a high-frequency transformer (HFT) rated at 7.6% of the total load power when operating at nominal voltage. A self-balance sensor-less strategy is integrated into the switching control and is used to control the voltage of the floating capacitor while the HFT balances two dc-links providing the required power flow. A Nearest Level Control (NLC) and an analysis of power distribution among each dc-link are presented in detail. Besides, comparisons with other multilevel topologies using HFT are carried out. Experimental results are presented to validate the proposed inverter and its floating capacitor control.