Kinetic Energy Harvesting

This chapter introduces principles of normal kinetic energy harvesting and adaptive kinetic energy harvesting. Kinetic energy harvesters, also known as vibration power generators, are typically, although not exclusively, inertial springmass systems. Electrical power is extracted by employing one or a combination of different transduction mechanisms. Main transduction mechanisms are piezoelectric, electromagnetic and electrostatic. As most vibration power generators are resonant systems, they generate maximum power when the resonant frequency of the generator matches ambient vibration frequency. Any difference between these two frequencies can result in a significant decrease in generated power. Recent development in adaptive kinetic energy harvesting increases the operating frequency range of such generators. Possible solutions include tuning resonant frequency of the generator and widening the bandwidth of the generator. In this chapter, principles and operating strategies for adaptive kinetic energy harvesters will be presented and compared.