Characteristics Research of a High Sensitivity Piezoelectric MOSFET Acceleration Sensor

In order to improve the output sensitivity of the piezoelectric acceleration sensor, this paper proposed a high sensitivity acceleration sensor based on a piezoelectric metal oxide semiconductor field effect transistor (MOSFET). It is constituted by a piezoelectric beam and an N-channel depletion MOSFET. A silicon cantilever beam with Pt/ZnO/Pt/Ti multilayer structure is used as a piezoelectric beam. Based on the piezoelectric effect, the piezoelectric beam generates charges when it is subjected to acceleration. Due to the large input impedance of the MOSFET, the charge generated by the piezoelectric beam can be used as a gate control signal to achieve the purpose of converting the output charge of the piezoelectric beam into current. The test results show that when the external excitation acceleration increases from 0.2 g to 1.5 g with an increment of 0.1 g, the peak-to-peak value of the output voltage of the proposed sensors increases from 0.327 V to 2.774 V at a frequency of 1075 Hz. The voltage sensitivity of the piezoelectric beam is 0.85 V/g and that of the proposed acceleration sensor was 2.05 V/g, which is 2.41 times higher than the piezoelectric beam. The proposed sensor can effectively improve the voltage output sensitivity and can be used in the field of structural health monitoring.

Design Optimization of Bulk Piezoelectric Acceleration Sensor for Enhanced Performance

While seeking to achieve high performances of a bulk piezoelectric acceleration sensor, we investigated the behavior of the design variables of the sensor components and optimized the sensor design using a numerical simulation based on piezoelectric analysis and metamodeling. The optimized results demonstrated that there was an exponential dependency in the trade-off relation between two performance indicators, the electric voltage and the resonant frequency, as induced by the design characteristics of the sensor. Among the design variables, a decrease in the base height and epoxy thickness and an increase in the piezo element’s inner diameter had a positive effect on two performances, while the head dimensions (diameter and height) exhibited the opposite effect on them. The optimal sensor designs are proposed within the valid range of resonant frequency (25–47.5 kHz). Our redesign of a commercial reference sensor improved the resonant frequency by 13.2% and the electric voltage by 46.1%.

Performance enhancement of MEMS-guided four beam piezoelectric transducers for energy harvesting and acceleration sensing

In the present paper, guided four beam (G4B) piezoelectric transducers with enhanced sensitivities have been designed. Based on the suggested G4B structures, piezoelectric energy harvesters (PEHs) and acceleration transducers with higher voltages than their previously reported counterparts and with lower displacements than the single-cantilever PEHs (SC-PEHs) have been proposed. We have shown that it is possible to arrive at much more output voltages in comparison with the conventional PEHs by redesigning the structure of the cantilever beams. In 1 g acceleration, the maximum output voltage obtained from the proposed PEHs has been 13.49 V whereas the output voltage for the conventional G4B-PEH is 2.87 V. This paper for the first time proposes G4B-PEHs with smaller displacements and larger voltages compared to a SC-PEH. The same G4B framework has been studied as a piezoelectric acceleration transducer. The effect of piezoelectric length on the extracted voltage in both unimorph and bimorph cantilevers has been discussed and the optimized length has been calculated. An analytical method is developed to compute the resonance frequencies of different beam shapes whose results are in a good agreement with numerical simulations.

Design of Signal Processing Circuit under the Principle of EMC of the Piezoelectric Acceleration Sensor

Although piezoelectric acceleration sensors enclosure can shield electromagnetic pulse commendably, the electromagnetic pulse can be coupled into the sensor and interfere signal processing circuit in the high-frequency electromagnetic environment, which can lead to the failure of acceleration sensor. So, the reasonable design and optimization are necessary for the improvement of signal processing circuit anti-electromagnetic interference ability under the principle of EMC. Some methods were proposed in this paper, such as adding a filter circuit, increasing the spacing between the wires and increasing the number of ground wires, etc. Finite integration technique (FIT) is used in this paper for these simulations in CST software. Simulating results show that the transfer impedances of signal processing circuit under the high-frequency electromagnetic interference were greatly reduced after optimization and power integrity was greatly improved. It achieves the goal of enhancing electromagnetic interference resistance of the signal processing circuit, thereby reduces the influence of the electromagnetic pulse on the piezoelectric acceleration sensor greatly.

Design of High Performance Signal Disposal Circuit for Piezoelectric Acceleration Sensor

According to general piezoelectric acceleration sensor measurement circuit existing problems in the dynamic testing field, the paper proposes the modular, integration design method, using the integrated chips CA3140 to design the signal disposal circuit, in order to reduce the cost and improve the circuit SNR, enhance the stability and reliability of the circuit. This circuit includes a charge amplifier, conditional amplifier, low-pass filter, high-pass filter and output amplifier. The test shows that the circuit functions are complete, it is practical and reliable. It has a higher performance price ratio, and can be widely used in the dynamic monitoring and the diagnosis of fault or defect about the equipment and structure.

Motion Trajectory Simulation and Measurement of the 5000V Electromagnetic Repulsion Mechanism (ERM)

Successful applications of the ERM depend on accurate simulation models. Firstly, we built up a model on the 5000 volts ERM with ansoft. Then we measured motion trajectories of the ERM prototype respectively by means of a piezoelectric acceleration transducer, a magnetic grating displacement transducer and a linear displacement sensor. Based on the comparative analysis of the results from simulation and measurement, we concluded that the simulation model was reliable on one hand, and on the other hand by means of a linear displacement sensor along with a magnetic grating counterpart, we could obtain accurate motion trajectories with a relative error less than 5%.

Design and Research on Piezoelectric Acceleration Geophone

A kind of piezoelectricity acceleration geophone is studied and discussed. carried on its amplitude frequency, phase-frequency characteristic theoretically, obtained the primary factor of the influence on frequency response, and improved in the piezoelectric crystal choice and geophone structure. The theory and the field test result indicated that, this piezoelectricity acceleration geophone has better response characteristic on low frequency and the high-frequency as well as a higher sensitivity, it is one better detection method.