A dynamic model for optimization of reciprocating energy harvest topologies
Abstract
In many sensing applications, it is desirable to harvest the energy from random motion to power data acquisition, communication, and control circuits. However, constraints on size and mass often require one to explore the feasibility of energy harvest over traditional energy storage devices (i.e. batteries). In this research, tools are developed to enable the study of energy harvested versus size (mass/volume) for systems consisting of a multi-pole, air-core permanent magnet, spring, coil, and diode rectifier packaged within a rigid body device of arbitrary geometry. At the heart of the tool are time-domain, mechanical models of the magnet translation and the rigid body rotation under the influence of external and reciprocal internal forces. The models are derived to consider friction internal to the device as either viscous friction or Coulomb friction. The motion of the permanent magnet is used within an electrical system model of the magnet/coil/diode to establish coil current and electromagnetic force on the magnet. The combined mechanical/electrical model has been validated by verifying conservation of momentum and energy and comparing results with analytical predictions for oscillatory frequency and damping. Subsequently, the model has been used to characterize the energy harvest capabilities of a mobile, wireless sensor designed to measure and transmit water-quality data within a water distribution system.
Degree
M.S.E.C.E.
Advisors
Pekarek, Purdue University.
Subject Area
Electrical engineering|Mechanical engineering
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