Electrostatic induction power generator using hydroxyapatite ceramic electrets

Abstract In this paper, we examine the power generation performance of a rotational electret power generator theoretically and experimentally using electrostatic induction based on the properties of hydroxyapatite (HAp) ceramic electrets; the two surfaces of the electrets have opposing polarities. The HAp electrets have long-term stability in comparison with polymer electrets, which are more commonly used. The theoretical power output is proportional to the square of the total surface area of electrets per block of the stator, frequency of the rotor, and surface electric potential of the electret. Moreover, the power output is proportional to the square of the inverse of the air gap between the rotor and electrets. The behavior of power outputs obtained under different experimental conditions correlated with our theoretical prediction. The maximum output power generated by our prototype electret generator was 3.6 μW with the frequency of the rotor being 24 Hz.