On the efficiency of electric power generation with piezoelectric ceramic

This paper analyzes the efficiency of piezoelectric ceramic far purposes of electric power generation. An analytical model is presented rr which sugge sts that the primary problem of using PZT for electric power generation is that most energy is stored in the ceramic and returned to the mechanical po rt. The efficiency as a function of force input frequency and resistive loa d are derived based upon a linearized model of a commercially available PZT stack. The analysis yields counterintuitive results in that maximum effici ency occurs in a low frequency region, several orders of magnitude below th e structural resonance of the stack The analytical results are followed by presentation of experimental data that substantiate the model. The model is then utilized to show that, due to hysteresis in the ceramic, the efficien cy of energy transfer is dependent on the amplitude of force input, and tha t greatest efficiencies can be achieved with maximum input forces.