Nacelle-to-Tower Multilevel IPT System for Small-Scale Wind Turbines

The use of small-scale wind turbines (SSWTs) in private households not only allows for increased renewable energy generation but also improved grid stability and resilience of individual regions. However, there are strict requirements regarding the efficiency, reliability, and electrical safety of SSWTs because of their low power levels, long payback period, and the fact that they are installed nearby residential areas. This article proposes a novel yaw inductive power transfer system based on a multilevel converter, which mitigates the main disadvantages of SSWTs-slip rings, low-voltage energy generation, etc. The system utilizes low-voltage mosfets in multilevel boost-series resonant topology combined with zero-voltage switching techniques to maximize efficiency. The operating principle, switching waveforms, and behavior of the converter are described and analyzed. The cell voltage balancing algorithms are presented as well. Two different control techniques for power flow regulation have been introduced and compared. The effectiveness of the proposed solution has been verified by building a 3.3-kW prototype system and a comprehensive measuring of its performance. The experimental results show that the peak power transfer efficiency reaches 92.5% while converting generator voltage from 60 V dc to grid compatible 400 V dc.