Comparison of four electrical interfacing circuits in wind energy harvesting

There has been growing research interest in converting ambient energy in the environment to electricity in order to realize self-powered electronic systems such as wireless sensor networks. This paper targets wind energy as an alternate power source. While structural modification of a wind energy harvester contributes to the power enhancement, the electrical interfacing circuit is also vital for the system optimization. However, despite the enthusiastic investigation on interfacing circuit in the field of base vibration energy harvesting, it has been frequently ignored in wind energy harvesting researches. This paper evaluates and compares the performances of four electrical interfacing circuits in a galloping-based wind energy harvesting system, including the synchronous charge extraction (SCE) circuit, series and parallel synchronized switch harvesting on inductor (SSHI) circuits as well as the standard circuit. Based on the analysis, a guideline is proposed for circuit selection in different circumstances. It is concluded that the SCE circuit is suitable for weak coupling and higher wind speed conditions. The two SSHI circuits are recommended in both weak coupling and medium coupling conditions, especially when a low cut-in wind speed is desired. The series-SSHI circuit is suggested in high terminal load situation while the parallel-SSHI circuit is recommended in small terminal load condition. If strong coupling presents, the standard circuit is recommended considering its simplicity and equally good performance with that of the SSHI interfaces. In special, it is found that the behavior of the ranges of ke2 for the SCE, S-SSHI and P-SSHI with enhanced power over the standard circuit is different from the case of base vibration energy harvesting.