Hysteresis controlled MPPT for piezoelectric energy harvesting

Abstract

A hysteresis controlled MPPT method is proposed to improve the efficiency of piezoelectric energy harvesting (PEH). According to the characteristics of the PZH output power, the maximum output power can be obtained when the piezoelectric transducer (PZT) output voltage is controlled nearby the 1/2 open-circuit voltage (optimal output voltage). A hysteresis window for maximum power point controlled is implementing with the energy storage circuits, which optimize the voltage of PZT output after rectification to optimal output voltage. Experimental results show that the MPPT control method with the hysteresis window can effectively track the optimal output voltage. The maximum power tracking efficiency η_MPPT is high to 98.7% with the variety of the ambient vibration energy.