Electrodynamic Vibration Energy Harvesting for IoT/IIoT - with State-Average Boost Converter

This example is intended to show relevant modeling and simulation capabilities of SystemVision Cloud, for electrodynamic energy harvesting (EH) systems. It is not necessarily a practical EH design itself, but rather demonstrates the tool's ability to support knowledgeable users who are creating practical designs.

The mechanical and magnetic circuit sections of the model are composed of "physical" models, in that user can directly specify size and physical properties of the components. This includes the mass of the armature, the stiffness of the resonant spring, the cross section area and length of the magnetic core, the residual flux density of the permanent magnet, and the number of winding turns.

The electronics section (rectifier and boost converter) contains a mix of passive analog circuit elements as well as abstract or "math block" models to represent the state-average (non-switching) behavior of the converter. Finally, constant power load model represents the power demand for periodic transmission of data typical of an (I)IoT sensor node.

In the simulation results displayed on the schematic, the upper right waveform viewer shows the amplitude of the external vibration source (e.g. a motor or transformer housing) of 0.07mm peak at 60 Hz, equivalent to a peak acceleration of 1g (light-blue waveform). The armature spring-mass resonance frequency is 60 Hz, so the armature displacement is seen to reach the frame's travel limit of 4mm peak-to-peak (green waveform).

In the upper left, the two waveform viewers are zoomed-in near the 1 second simulation time mark, and they show the air-gap lengths and the corresponding core flux density and winding voltage. Note that the air-gaps are configured in parallel for the flux path, so the effective path reluctance is minimized when either gap approaches zero length.

In the lower right, the relatively low value of the rectified "DC" voltage is observed (red waveform), as well as the regulated boost output voltage that supplies the transmitter load.

KDAS's picture




Joined April 18, 2018
Design added Wednesday, June 6, 2018 | 1:35 am PDT