Here are some classic resources and papers on multilevel inverters that you can refer to for more information:
J. Rodriguez, J.-S. Lai, and F. Z. Peng, "Multilevel inverters: a survey of topologies, controls, and applications," IEEE Transactions on Industrial Electronics, vol. 49, no. 4, pp. 724-738, Aug. 2002. (A comprehensive survey of multilevel inverter topologies, controls, and applications)
L. G. Franquelo et al., "The age of multilevel converters arrives," IEEE Industrial Electronics Magazine, vol. 2, no. 2, pp. 28-39, June 2008. (A review of the state-of-the-art in multilevel converter technology)
A. Nabae, I. Takahashi, and H. Akagi, "A new neutral-point-clamped PWM inverter," IEEE Transactions on Industry Applications, vol. IA-17, no. 5, pp. 518-523, Sep./Oct. 1981. (A classic paper that introduces the neutral-point-clamped (NPC) multilevel inverter topology)
These resources should provide a solid foundation for understanding multilevel inverter topologies, including the cascaded H-bridge configuration. Once you are familiar with the basic concepts, you can explore more recent papers and articles to learn about the latest developments and improvements in the field.