## 6 Conclusions  
This work proposes and defines a three-phase wind energy harvester system plus different AC/DC converter architectures to collect energy and transform it into DC power.  
The AC/DC converter architectures are implemented with different devices, analyzing their main characteristic parameters such as voltage, power and efficiency. Among the architectures considered, the Split NP architecture was chosen as the most suitable to implement the AC/DC converter, for it provides the best performance figures. Test results show that the harvester gives 15-133 mW at two extreme ambient conditions; the aforementioned architecture has an efficiency between 81.52% and 74.33%, better than the standard D-bridge architecture used as reference that provides an efficiency between 35.02% and 42.64%.  
The test results also show that the most suitable devices for the AC/DC converter design were: MOSFET Si1553 CDLN and diode MBR0520L. The selected devices allow the identification of the key parameters to look at when choosing a MOSFET; these are low on-resistance and low gate capacitance. Likewise, the diode chosen is the one with lower resistance and fastest recovery time. Therefore, the device selection aims to reduce both conduction and switching losses of the converter.  
The converter switching frequency must be adapted to the wind conditions obtaining the best results for 200 kHz, 333 kHz and 500 kHz. Moreover, depending on the test case, the most adequate duty-cycle ranges from 0.4 to 0.5. Finally, the loads that provides the best results ranges between 100 \(\Omega\) and 1500 \(\Omega\).  
The proposed energy harvesting system works efficiently at different wind conditions. This research also demonstrates that the AC/DC converters are feasible topologies to be applied in the energy harvesting field and to different types of energy harvesters because the topologies employed in this work were used in the references provided with piezoelectric harvesters that give less energy than a wind harvester. Thus, the proposed system, with a three-phase wind energy harvester system and an AC/DC converter, is a promising technology for multiple small-scale energy applications such as IoT systems and applications to the Industry 4.0 concept.  
Conceptualization, B.P., H.Z., and L.M.; methodology, H.Z. and L.M.; validation, B.P., H.Z., J.I.G., and L.M.; formal analysis, B.P., H.Z., L.M., and J.I.G.; investigation, B.P., H.Z., and L.M.; resources, P.S.; data curation, B.P., J.A.A., and J.I.G.; writing--original draft preparation, B.P.; writing--review and editing, J.A.A., H.Z., and J.I.G.; supervision, L.M., J.I.G and P.S. All authors have read and agreed to the published version of the manuscript. This research received no external funding. This work was supported by the IK4-TEKNIKER research institute's own funds and the joint work of Electronics and Communications and Intelligent Information System units and by the Department of Education of the Basque Government within the fund for research groups of the Basque university system IT978-16.  
Figure 36: Proposal of electronic and wind harvester integration.  
Conflicts of Interest: On behalf of all authors, the corresponding author states that there is no conflict of interest.