The PiezoHydraulic Pump (PHP) used in this work currently uses proprietary check valves that allow the PHP to be operated at 1 kHz. At a bias pressure of 500 psi and operating voltage of 1 kV, the PHP produces a mechanical power output of 46 W. The PHP was baseline tested using both the proprietary valves (internal) and external commercial passive check valves. Using the external valves at a bias pressure of 80 psi, the PHP was tested at various frequencies. At an operating frequency of 150 Hz, the maximum flow rate was 0.91 cc/s, while at 125 Hz, the maximum mechanical power output was 0.18 W (0.64 W/kg). This significant decrease in characteristics can be attributed to an increase in system compliance by moving the valves external to the pump housing and possible air entrapment within the chamber.
This paper presents a new approach using frequency rectification to harvest electrical energy from mechanical energy using piezoelectric devices. The rectification approach utilizes a linearly traveling Rectifier to impart vibrational motion to a cantilever piezoelectric bimorph. A conventional cantilever-type energy harvester is tested aside the rectified beam. The Standard beam generated 0.11 W of power, a power density of 15.63 kW/m3, and an energy density of 130.7 J/m3. The Rectified beam generated 580 mW of power, a power density of 871.92 kW/m3, and an energy density of 313.15 J/m3, a factor 2.4 greater than conventional energy harvesting methods. These results confirm the original thesis that a mechanically rectified piezoelectric Energy Harvester would generate larger Energy and Power Densities as well as Specific Powers, compared to conventional technologies.
In this article, four types of piezoelectrically driven motors are evaluated: linear, horn-type, unidirectional rotary, and bidirectional traveling wave. Experimental results for velocity, power, and specific power are presented as a function of mechanical load. Analytical and experimental energy densities are compared based upon applied electrical potential. The bidirectional ultrasonic motor exhibited 34% of its available energy density, while the other motors produced values ranging from 0.63 to 9.5% of their respective available energies. The piezoelectric material specific power values ranged from 4500 W/kg for the bidirectional motor to 6.53 W/kg for the linear piezo motor. Results suggest that comparing piezoelectric motors based on individual mechanical parameters does not accurately describe motor design and drive train energy transmission.
Piezoelectric actuators have attractive operating properties because they do not generate electromagnetic fields and are not affected by them, and their power output characteristics scale linearly with decreasing size. These actuators have not seen widespread industrial use, however, because they have shown a limited power output. This work presents the initial efforts to increase the available power output of the Piezoelectric Ultrasonic Motor (PUSM). Commercially available PUSMs are limited by the small friction forces generated at the rotor/stator interface. Small friction is generated because current PUMs use rubber or polyimides on the rotor to create as the contact with the stator. Traditionally, PUSM contact material has consisted of rubber or reinforced polyimides. The authors intend to replace the traditional contact layer with a compliant super-elastic Nickel-Titanium (NiTi) thin film shape memory alloy (SMA) layer to increase the available power output by increasing the friction forces at the rotor/stator interface, without significantly increasing the size or weight of the actuator. The unmodified motors were baselined tested, modified, tested and the results compared. Recommendations are made with regard to the results of the modified baseline testing and possible implementation of micromachined ‘teeth’ configurations.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.