This paper proposes a structure of energy harvester that is used to scavenge environment energy to power wireless sensor nodes. The ambient energy usually is from sunlight, wind, vibration, and so on. As the size of a sensor node is limited, the energy converted is normally small and has a prodigious random fluctuation. In order to improve the conversion efficiency of energy harvester, the paper proposes a power conversion circuit to collect rapidly paroxysmal energy generated by external environment. The circuit, as a power conditioner, bridges between energy transducers and the load of a wireless sensor node, and the power output of transducers are either AC or DC. The power conditioner implements AC-DC conversion, voltage adjusting and energy storage. A design model is developed to describe the dynamic behavior of the power conditioner under the different excitation from ambient energy sources, and energy conversion efficiency can be evaluated with the model. The proposed system architecture can be applied in the design of solar, wind or stochastic vibration energy harvesters.
Low Frequency Electromagnetic Structural Vibration Energy Harvester to Power up Wireless Sensor Node
