Optimal design and application of a piezoelectric energy harvesting system using multiple piezoelectric modules

To enhance the output power of piezoelectric energy harvesting system up to the watt level, we designed a multi-piezoelectric array (MPA) energy harvesting system that can overcome the limitations of a single-piezoelectric harvesting systems. The MPA energy harvesting system was designed using an impact-type harvester utilizing a hitting stick, as such systems can generate higher output power than vibration-type methods using a cantilever in a single-piezoelectric energy harvesting system. We investigated the effects that various connection and rectification methods had on the output power of a piezoelectric energy harvesting system consisting of four 35 ×45 × 0.2 mm3 piezoelectric modules. We found that the output power was highest when each module was rectified before the modules were connected in parallel and that the optimal load resistance was inversely proportional to the number of modules if they were connected in parallel. To obtain watt-level power from the proposed MPA energy harvesting system, we designed a system consisting of 102 piezoelectric modules based on the derived optimized experimental conditions, from which we were able to obtain an output power of 1.99 W at 1800 hpm (hits per minute) and 500 Ω.