Investigation on behavior of the vibration-based piezoelectric energy harvester array in ultracapacitor charging

In this article, behaviors are investigated when the piezoelectric harvester array, consisting of four lead zirconate-titanate (PZT) circular diaphragms, charges ultracapacitors. It exhibits that V-I characteristic of the harvester array is approximately linear within 3RC, demonstrates that the array could be equivalent as the linear source. Relevant factors on ultracapacitor charging power P, including equivalent circuitry impedance R, charging capacitor C, operating frequency f, and connection patterns, are also studied. Meanwhile, interrelation between energy charging efficiency η and maximum charging power PMS is demonstrated, which is also used to find out the best condition for the harvester array's operation. It exhibits that PZT harvester array connected in pattern of rectifying-parallel will have higher charging efficiency.