Optimal Control for Energy Harvesting: Electrical Model and Measurements

Abstract: The energy harvesting of piezo-electric devices is not simple nor straightforward. The complex internal structure of the device makes the AC-DC conversion too involved. The buck-boost topology showed to be effective in discontinuous mode providing a constant input impedance for small amount of power. In this paper a closed-loop optimal control algorithm to deal with any kind of electrical voltage input of a buck-boost converter is considered. This optimality yields a much bigger output power when compared to the case of non-optimal control. Application to piezo-electric devices is focused with the energy harvesting in mind, in this case the sudden drop of energy exhibited by the nature of the piezo-device is significantly mitigated by the optimal algorithm. Some simulations as well as comparisons with real measurements using a commercial piezo-electric device are presented along with conclusions and future work.