Multi-Phase Bipolar Rotary Electret Power Generator with DC Output Current

Inspired by an electromagnetic hydropower station that contains reverse polarized magnets, this paper reports a multi-phase bipolar rotary electret power generator (MB-RPH) with a DC output current. It is capable of generating an almost constant current output with a low crest factor by phase coupling caused by multi-phase structure and integrating both positive and negative charged electret into monolayer rotary power generators by bipolar charging to improve output performance. Experiments show that the output power of each phase is increased to about 367% by bipolar charging ' the output performance significantly increases as the phase increase and the crest factor of current substantially decreases as the phases increase. The MB-RPG with three-phase produces an output voltage of 163.5 V, output current 4.3 µA at 600 rpm and an average output power of 1.05 mW. The MB-RPG not only has high-performance output but also realizes an almost constant DC output, which is of considerable significance to the practical application of sensor energy supply.