**7. Conclusions**

This paper proposes a switching hybrid modulation strategy, which can e ffectively reduce the fluctuation of DC-side voltage and maximize the output power of a PV CHB grid-connected inverter. When the CHB inverter is operating in the normal mode, the hybrid modulation strategy containing the zero state is adopted to suppress DC-side voltage fluctuation, thereby improving the output power of PV modules. Once the CHB inverter is operating in the fault mode, owing to failing solar panels, the hybrid modulation strategy without the zero state is utilized to make the DC-side voltages reach the references, thus, maintaining a higher energy yield under the fault condition. A set of experimental results demonstrate that, with this method, the output energy of the PV modules is improved both in the normal mode and fault mode.

**Author Contributions:** Conceptualization: X.Z. and W.M.; data curation: Y.H.; formal analysis: W.M. and T.Z.; funding acquisition: F.W. and F.L.; methodology: X.Z.; resources: X.Z. and R.C.; software: Y.H.; validation: W.M.; writing—original draft: W.M.; writing—review and editing: W.M.

**Funding:** This work was funded by the National Key Research and Development Program of China (No. 2018YFB1500703) and the National Natural Science Foundation of China (No. 51677049).

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