Kinetic energy harvesting from low-frequency sources

David Francis Berdy, Purdue University

Abstract

Advancements in low-power electronics, wireless communications, and battery technology have made it possible to untether devices from the wall, allowing mobile, wireless electronics, such as cell phones, personal music players, patient monitoring sensors, and wireless sensor nodes. Although these advancements have enabled electronics to be liberated from wired power sources, the lifetime limitation of batteries has posed significant barriers in some applications, especially in wireless sensor nodes where battery replacement is difficult or dangerous. Present in many electronics' and sensor nodes' environments is a rich source of ambient vibration energy available to be harvested to supplementally recharge the battery. Energy harvesting utilizing magnets and piezoelectric materials to convert mechanical vibration energy into electrical energy has gained significant attention recently. However, the high natural frequency and limited bandwidth of most devices has limited their use in many applications. This dissertation focuses on the development of low-frequency vibration energy harvesters. First, a wide-bandwidth, meandering piezoelectric vibration energy harvester targeted for wireless sensor node applications is presented. The device achieves a low resonant frequency and wide bandwidth due to its closely spaced modes, enabling it to more effectively harvest energy from the commonly occurring low ambient vibration frequencies (20 Hz and higher). Second, a magnetic levitation electromagnetic energy harvester is developed and optimized for harvesting kinetic energy from human movements while walking or running, where most of the acceleration content is below 10 Hz. The device design and optimization is presented along with real-world measurements from human subjects.

Degree

Ph.D.

Advisors

Jung, Purdue University.

Subject Area

Electrical engineering|Mechanical engineering

COinS