Optimizing Energy Harvesting of a Composite Unimorph

Energy harvesting of piezoelectric actuators has been studied in the past. One of the biggest challenges is designing the circuitry necessary to harvest the energy of high impedance piezoelectric actuators and determining what factors affect their performance. Experiments have been conducted using a pre-stressed unimorph ferroelectric actuator (Thunder) with matching circuitry to measure the electrical energy produced by a single stroke mechanical action. This particular piezoelectric actuator is a composite of a ceramic, a polyimide adhesive, and a metal pre-stressed at elevated temperatures. The parameters varied for this particular set of experiments were the adhesive composition, and the thickness and type of the metal. Displacement under no-load, capacitance, physical dimensional parameters, and electrical energy output were measured for each configuration. The circuit utilized to measure energy used a voltage regulator, and a combination of resistors, and capacitors, so that the electric output of the actuators is controlled eliminating voltage peaks. The energy is then measured by the length of time the voltage ca