Resonant electromagnetic vibration harvesters applications: Optimization of P&O MPPT technique parameters

In this paper it is shown that Resonant Electromagnetic Vibration Energy Harvester (REVEH) systems nearly always need to be equipped with suitable MPPT (Maximum average Power Point Tracking) controllers due to the fact that the characteristics of vibrations (frequency, amplitude etc.) change with time. The particular (but frequent) case of Constant Frequency Time Varying Amplitude (CFTVA) vibrations will be considered. In particular, the guidelines for the optimization of the P&O MPPT technique to adopt in REVEH systems in the case of CFTVA vibrations are provided. It is demonstrated that both the sampling frequency f
_P&O
and the amplitude Δd of the P&O duty cycle perturbation need to fulfill suitable inequalities in order to get an efficient REVEH system.