Open Access

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 paper proposes a novel yaw inductive power transfer system, based on multilevel inverter, 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 ZVS techniques to maximize efficiency. The operating principle, switching waveforms and behavior of the inverter are described and analyzed. 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 comprehensive measuring of its performance. The experimental results show that peak power transfer efficiency reaches 92.5% while converting generator voltage from 60 V DC to grid compatible 400 V DC.