Consumption evaluation of a relaxation oscillator as a control sampling circuit for fast-tracking FOCV-MPPT circuits in wave energy converters

Energy harvesting (EH) sources require a power management unit (PMU) with maximum power point tracking (MPPT) functionalities to maximize the energy generation.One simple MPPT approach, widely used in low-power EH applications and thoroughly explained in [1], is the fractional open circuit voltage (FOCV) method.In this method, maximum energy is harvested by fixing the output voltage of the EH source to the maximum power point (MPP) voltage (V MPP ), which is a percentage of its open circuit voltage (V OC ).Typically, V OC is periodically measured (at a sampling period of T MPPT ) by momentarily disconnecting the EH source from the PMU during a sampling time (t SAMP ) and storing the V OC corresponding to the new environmental conditions.