Theoretical analysis of electrostatic energy harvester configured as Bennet's doubler based on Q-V cycles

Abstract

We present a theoretical analysis of a MEMS electrostatic energy harvester con-figured as Bennet's doubler. The steady-state operation of the circuit can be approximated by a rectangular Q-V cycle in the ideal case or by a trapezoid diagram when the electrical losses are taken into account. A similarity between the voltage doubler and charge-pump circuit is highlighted. The analytical solution of the saturation voltage is derived, providing a more insightful comprehension of the system performance and the influence of its parameters. The results obtained from studying the Q-V diagram coincide with those of circuit simulations for both cases when using (i) a mathematically idealized diode or (ii) a realistic diode model that includes the electrical losses. A configuration employing a simple switch connected in series with one of the three diodes that can further increase the saturation voltage is investigated, providing an efficient alternative for boosting the output voltage of an electrostatic energy harvester.