**5. Conclusions**

A novel SEPIC-based Z-source inverter that eliminates leakage current is proposed in this paper. The feature of the proposed topology is a combination of a Z-source inverter and a SEPIC converter, so the current inverter has the advantages of both a SEPIC converter and a Z-source inverter, which has a high voltage gain. Furthermore, the proposed inverter is controlled by a simple linear control method, which is easy to achieve, and the proposed inverter has a low voltage stress in the switch, which is beneficial for choosing switches. Furthermore, compared with traditional single-phase H4, H5, and HERIC topologies, the proposed topology has features including fewer switches and very low leakage current, which is helpful for the application of transformerless inverters. However, the proposed topology also has the merits of the SEPIC converter. It can be seen in Figures 6 and 10 that the proposed inverter has large output harmonics, due to the lack of a filter inductor. The simulation results verified the theoretical analysis. Furthermore, experiments with a laboratory prototype, using a DSP controller combined with FPGA, showed good results that were in agreemen<sup>t</sup> with the simulation results. The future research direction will be to study new control methods to reduce the output harmonics.

**Author Contributions:** This paper was a collaborative effort among all of the authors. All authors conceived the methodology, conducted the performance tests, and wrote the paper.

**Funding:** This work is supported by the National Natural Science Foundation of China under Grant 51777181.

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