Systematic investigation of bipolar-charged electret/triboelectric power generator: modeling, experiments and applications

Inspired by an electromagnetic hydropower station with a reverse polarized magnet, we proposed a new design methodology of electret rotatory power generator (e-RPG) with bipolar-charged electrets for boosting its output performance. A selectively localized corona discharging method is invented to have both positive and negative ultra-high-resolution charges implanted into a single electret thin film. A generalized theoretical model of unipolar-charged and bipolar-charged e-RPG is derived to evaluate their performance and the key features affecting their performance are the initial capacitances with different connection schemes. Experimental results show that: the output power of the bipolar-charged e-RPG is increased to 393.4% compared to those of the positive alone and negative alone configurations, which fully agree with those obtained from the theoretical model. Based on the modeling analysis and experimental verification, it is clarified the average output power of the bipolar e-RPG are increased up to 400% compared with those of the unipolar e-RPG, which provides a direction for the subsequent research on improving the output performance of the electret generator.