**6. Conclusions**

In this paper, three kinds of widely used wind generators—DFIG, direct-drive PMSG, and semi-direct-drive PMSG—are compared on the bearing current characteristics. The simulation results reveal that the bearing current of DFIG is much larger than the PMSGs. From the perspective of bearing reliability, PMSGs have more advantages than DFIG. From the common mode current point of view, the common-mode current of direct-drive PMSG is much larger than the semi-direct-drive PMSG and DFIG. Bearing current suppression methods for DFIG and common-mode current suppression methods for direct-drive PMSG should be further explored.

**Author Contributions:** Conceptualization, R.L.; Methodology, R.L.; Software, X.M., X.R.; Formal Analysis, X.M., X.R.; Resources, J.C.; Writing-Original Draft Preparation, X.M., X.R.; Writing-Review & Editing, R.L., S.N. Funding Acquisition, R.L., J.C.

**Funding:** This research was funded by the National Natural Science Foundation of China gran<sup>t</sup> number [51777008, 51577007].

**Acknowledgments:** The authors express their gratitude to the National Natural Science Foundation of China.

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