Maximizing the Power Output of a Piezoelectric Harvester by Optimal Resistive Load

The paper focuses on simulating the optimal resistive load for a piezoelectric harvester’s power output maximization. The piezoelectric cantilever is simulated with a 4 g tip mass, according to the laboratory experiment, in order to obtain a valid comparison. The article shows how the power output increases with more than one order of magnitude with the optimal impedance of 21 kΩ + 50 pF, compared to the simulations with the input impedance of the spectrum analyser used in laboratory, of 1 MΩ + 50 pF. The capacitance was left unchanged, with only the electrical resistance being modified. Under these conditions, the power output increases from 0.797 mW to 9.973 mW. The numerical simulations employ a fully coupled digital twin. Frequency-domain studies were conducted using systematic auxiliary sweeps of the load resistance, progressively narrowing the search range from coarse to fine steps until the optimal resistance value was computed with the desired precision.