Power enhancement of a monostable energy harvester by orbit jumps

Energy harvesting has been regarded as a potential solution for power problems in wireless sensor network applications over batteries. Nonlinear configurations, as one of the most promising methods for broadening bandwidth, still make the system suffer from the coexistence of high-energy orbit and low-energy orbit, which significantly reduces output power. This paper proposes the electromagnetic kick method to enhance the output power of a monostable energy harvester through orbit jumps. The so-called electromagnetic kick is introduced by a solenoid consisting of a coil from the electromagnetic energy harvester and a three-volt button battery. The modeling and analysis demonstrate the excitation capability of the electromagnetic kick for orbit jumps. Inspired by a swing, two strategies are derived as the single kick and cycled kick. Based on an experimental setup, parameters for two strategies are first determined. The single kick and the cycled kick are then respectively employed to realize orbit jumps for the energy harvester under varying excitation and loading conditions. For each scenario, twenty trials are repeated to investigate the probability and capability. The system power output can be boosted from null to over 360 µW after orbit jumps, and the consumed energy can be resumed within 20 s. In addition, to evaluate different orbit jumping approaches in the literature, a figure of merit is developed, and the comprehensive advantages of the electromagnetic kick approach are demonstrated. The proposed effortless and efficient orbit jumping strategy expands the possibilities of realistic applications of nonlinear energy harvesters. The defined figure of merit not only makes it possible to compare different orbit jumping methods but also opens the door to new strategy development.