Power Conditioning for Energy Harvesting - Theory and Architecture

This chapter presents the fundamental principles of power conditioning circuits connected to harvesting transducers. While the focus is on motion-driven harvesters, much of the discussion is relevant to other harvester types. The power conditioning circuitry within an energy harvesting systems plays a pivotal role, exerting control over the harvester through its input impedance while at the same time performing power processing functions such as regulation, filtering, and rectification, and finally delivering energy to the load. When attempting to understand the behavior of a harvester and power conditioning circuit, it is often useful to consider the current and voltage waveforms at the terminals of harvesters in the frequency domain. The well-known peak rectifier (diodes followed by a reservoir capacitor) is widely used as the first power conditioning stage in AC energy harvesting applications; however analysis of such systems is more involved than their simple schematic suggests.