Real time temperature measurement for multilayered piezoelectric stack actuators

Self-heat generation is a common phenomenon in piezoelectric actuators used in high speed applications. Driving frequency and applied voltage are the two primary contributors to self-heat generation, which eventually rise the actuator temperature. Material properties such as dielectric properties, piezoelectric constants etc. are dependent on the actuator temperature. Also the positioning accuracy is greatly affected due to the temperature rise in piezoelectric actuators. To compensate the position error in piezoelectric actuators due to temperature changes, a real time temperature measurement is required, A novel method is proposed in this study to measure temperature from real time capacitance measurements. Piezoelectric capacitance is linearly related to the actuator temperature for all voltage ranges. Hence, a correlation between the piezoelectric capacitance and temperature can be obtained to measure temperature from real time capacitance measurements. The real time temperature measurement can be used to compensate for temperature effects in sensorless position control applications.