Electromotive Force of Piezoelectric/Thermoelectric-Combined Power Generator under Vibration and Temperature Gradient

Abstract

We have investigated the electromotive force (EMF) of a composite sample consisting of a Π-type thermoelectric power generation structure with a pair of n- and p-type Si wafers and piezoelectric devices in order to collect electricity from vibration energy and thermal energy, simultaneously. The observed EMF was obtained by superimposing the oscillating EMF of vibration energy on the constant EMF of thermal energy. Therefore, we have improved the composite sample with diodes for rectifying the oscillating EMF. As a result, the full-wave rectification and the preservation of EMF amplitude were realized. From the frequency dependence, it was found that the dielectric loss of the piezoelectric device influences the amplitude and the time delay in the EMF.