Office of Technology Transfer – University of Michigan

Power Scavenger Architecture for Low-Frequency Ambient Vibration

Technology #4362

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Khalil Najafi
Managed By
Joohee Kim
Licensing Specialist, Physical Sciences & Engineering 734-764-8202
Patent Protection
US Patent Pending


Wireless sensors, implantable devices, and other low-power gadgets typically obtain operational power in one of two ways: 1) by using electrochemical batteries or micro fuel cells and 2) by energy scavenging from environmental sources such as ambient heat, light, and vibration. Although electrochemical batteries and fuel cells can provide more power, they are not desirable for some applications due to their limited lifetime, size, and/or weight. Energy scavenging is becoming more feasible because miniaturization and other technological advances have reduced power consumption. Most research and commercial efforts to develop vibration scavengers are designed to harness energy coming in at a single steady frequency. The use of such resonance-based generators can have some drawbacks, however, such as the need to be tuned to their environment and the difficulty in scaling these devices when the vibration frequency decreases, both in terms of size and power density.


Researchers at the University of Michigan have developed the architecture of a new miniature power generator capable of extracting energy from low-frequency high-displacement motion. The Parametric Frequency Increased Generator (PFIG) uses an inertial mass to couple mechanical energy from the surroundings, and store it in the spring of one of two Frequency Increased Generators (FIG), located above and below, which convert this mechanical energy into electrical. The converted energy can then be used to power various wireless electronic devices.

Applications and Advantages


  • Wearable and implantable devices
  • Environmental monitoring
  • Agricultural, security and military uses


  • Scavenges energy from ambient motion that is infrequent and does not occur regularly.
  • Does not need to be tuned to the environment.