Endurance and temperature testing of a PMN-PT single crystal energy harvester for rotorcraft wireless sensor applications

Vibrational energy harvesting devices are a possible solution to problems posed by conventional power sources for structural health monitoring. These harvesters take ambient vibrations and convert them into usable power without the need for heavy wiring or batteries. However, conventional piezoelectric materials (PZT) are becoming less desired as compared to newer single crystal materials (PMN-PT), which offer better piezoelectric performance. Unfortunately, single crystals have not been researched adequately for use in energy harvesters. This work aims to quantify critical single crystal energy harvester design parameters by investigating PMN-.32PT single crystal devices in long-duration, high temperature, and high acceleration environments typical of rotorcraft applications. The harvester proved to be a reliable source of power generation and is practical for harvesting usage. A lab test article produces 25 V_RMS at 1.0g base acceleration at room temperature and is stable for 120 hours of continuous use. Its performance exhibits strong temperature dependence that may be abated by using different material compositions. The output power of a prototype compact harvester is sufficient for low-power sensors, but may be increased by utilizing thicker piezoelectric materials. At 1.0g and room temperature, the harvester outputs 2.7 mW_RMS of power through simple harvesting circuitry and a 10 kΩ resistive load A scalability study is being conducted to compare size and mass of a prototype compact device for use at a range of frequencies of interest.