High Energy Piezoelectric Pulse Generator

This investigation characterizes and models a high energy piezoelectric pulse generator (PPG) constructed from commercially available piezoelectric materials. The PPG converts mechanical energy into electrical energy, storing that energy in its internal capacitance. The energy storage of the PPG developed here is more than an order of magnitude greater compared to previous investigations. The large internal capacitance in the PPG is created by stacking numerous single-element piezoelectric devices and electrically connecting them in parallel. The total internal capacitance of the PPG is 0.15 muF. The PPG is piezoelectrically charged to 1000 Volts, thereby storing nearly one joule. The mechanical force needed to compress the PPG can be derived from many sources. However, in the laboratory, the mechanical force is developed from an identical PPG configured to operate in reverse as a force generator and powered by an external electrical power source. Peak forces on the order of 17 kN are needed to compress the PPG. An electromechanical model of the PPG is developed in PSpice and used to predict the performance of the PPG under a variety of conditions. The PPG is modeled as a lumped-element mechanical system consisting of a mass, spring, and dashpot. The PSpice simulations are compared to experimental test results with mechanical force rise-times ranging from sub-millisecond to several milliseconds. There is good agreement between the theoretical predictions and experimental results.