**7. Conclusions**

In this paper, a topology derivation methodology, named the "MN principle", is proposed to cover all possible full-bridge topologies with leakage current suppression under USPWM and DFUSPWM. Two types of NPC cells have been developed: one is called "indirect connection NPC topology", and the other "direct connection NPC topology". Under USPWM, twenty-three newly-found indirect connection NPC topologies have been derived along with the existing ones, and twenty-two newly-found direct connection NPC topologies have been derived along with the existing ones. The proposed method is also extended to the topologies under DFUSPWM. As a result, four corresponding topologies have been derived and one existing topology was also covered. Finally, simulations are given to verify the performance of the leakage current suppression of the proposed topologies. And it can be inferred that the contribution of this paper has important guiding significance for topological derivation.

**Author Contributions:** Conceptualization, X.Y., X.W.; funding acquisition, X.W.; investigation, X.Y.; software, X.Z.; validation, X.Z., X.W.; writing—original draft, X.Y.; writing—review and editing, H.W. and Y.-F.L. All authors have read and agreed to the published version of the manuscript.

**Funding:** Research on Topology, Passive Current Sharing Mechanism and Control for Multiphase Resonant Converter with Coupled Resonant Tank: 51977069; Research on High-power and High-efficiency Electro-acoustic Transduction Mechanism and Control Method: 51837005.

**Conflicts of Interest:** The authors declare no conflict of interest.
