A New Adaptive Capacitance Circuit for Piezoelectric Energy Harvesting

Vibration energy harvesting using piezoelectric materials has been developed significantly in recent years. In this method, the mechanical energy of a vibrating structure is converted to electrical energy using attached piezoelectric patches. Piezoelectric materials do not release the whole converted energy because of their inherent capacitor behaviour. So, a remarkable portion of the converted electrical energy is stored and rested on the piezoelectric capacitor. In the recent years, many researchers are trying to extract this portion using different har-vesting circuits. In this paper a new harvesting circuit with adaptive capacitor is proposed that in which approximately the whole converted energy can be extracted. In this method, electrical resonance condition is kept always in the circuit (harvesting circuit and the internal capacitor of piezoelectric element) for all vibration frequencies by choosing the desired adaptive capacitor in the circuit. By this way, the stored portion of the converted electrical energy flows into the circuit and can be extracted. Numerical results show a significant in-crease in the harvested energy compared with other techniques

کلیدواژه ها:

mechanical vibrations ، energy harvesting ، piezoelectric materials ، impedance matching.