Optimal Control of Electrical Interfaces for Triboelectric Kinetic Energy Harvesters Powering Low-Voltage Loads

Kinetic energy harvesters based on triboelectric nanogenerators (TENGs) typically have output voltages in the range of few hundreds to few thousands of volts. This voltage should be controlled by the conditioning circuit to maximize power conversion. In addition, the conditioning circuit must provide the converted energy to the electrical load at a regulated low voltage. In this paper, we present a buck-like interface controlled to ensure proper low-voltage regulation at the load, while maximizing converted power. The control is based on the mechanical operating conditions and on the transducer characteristics. Experimental results validate the maximum power points predicted from charge-pump theory and illustrate the operation of the energy-extracting circuit. The results highlight the impact of the non-idealities of this circuit.