Abstract
The performance of a fuel cell-powered piezoceramic actuator is investigated analytically and experimentally. Fuel cells are electrochemical engines that are comparable to batteries in specific energy density and can be instantly ‘recharged’ with the addition of fuel. This study focuses on the use of a methanol-powered alkaline fuel cell as a DC power source for a piezoceramic actuator exciting a thin beam. The fuel cell consists of a non precious metal cathode, a platinum anode, and a potassium hydroxide (KOH) electrolyte. The performance of the fuel cell is investigated by determining the voltage and power output as a function of the load current. A peak power of 30 mW is obtained with a 1M KOH electrolyte and 47 mW is obtained with a 4M concentration. A power analysis of constant-amplitude piezoceramic actuator demonstrates that low-power, efficient actuation is achieved by driving the actuator near an antiresonance of the coupled electromechanical systems. The antiresonance frequencies are determined from an admittance analysis of the coupled actuator and structure. Experimental results demonstrate that the power required for actuation in the kilohertz range is reduced from 4.5 to 1 mW by exciting the actuator at a known antiresonance, thus reducing the load on the fuel cell and increasing the effective lifetime of the actuator.
