Piezoelectric Energy Harvesting for Wireless Sensor Nodes

Background

Vibrations present around most machines, home appliances, and motion of biological systems are typical examples of a wasted energy that may be harvested. This source of energy is ideal for the use of piezoelectric materials, which have the ability to convert mechanical strain energy into electrical energy and vice versa (Sodano & Inman, 2005). In general, there are three mechanisms to harvest the energy from the vibrations: electrostatic, electromagnetic and piezoelectric techniques.

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  Electrostatic energy harvesters produce energy from capacitance changes during the vibration cycle, where the harvested energy is derived from the work done against the electrostatic force between the plates.

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  Electromagnetic energy harvesters generate energy from the induced current in coils as a result of the movement of a permanent magnet.

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  Piezoelectric materials can efficiently convert mechanical strain to an electrical charge without any need to additional power (Lee, 2010; Cook-Chennault et al., 2008).

Table 1 summarizes the main comparison points between the three different techniques.