Large signal measurements on piezoelectric stacks

The knowledge of the dielectric large signal properties of piezoelectric actuators for dynamic use is necessary to estimate the limits of application, to optimize the driving electronics, and to improve the actuator materials. A measurement technique has been developed for determination of the large signal parameters capacity, loss tangent, loss power, and dilatation in dependence on the control voltage amplitude, frequency, temperature, and bias field strength and first experimental results are presented. The effective capacitance, which has been measured with large control amplitudes, determined the output parameters of the control electronic and the stability of the set up. The loss power (loss tangent) influences the heating of the piezo-actuator when large control amplitudes and high frequencies are used. The comprehensive data files from the set-up include many additional information which can be evaluated by a comfortable evaluation software. A loss power hyperbola of piezo-actuators is derived being analogous to the loss power hyperbola of transistors. In addition, aging effects were investigated for the effective capacity, the loss power and the dilatation after a complete temperature and electrically field cycle. Harmonic distortion of the actuator current by controlling with large amplitudes and the change of the loss power by controlling with saw tooth and rectangular control voltages have bee measured.