Office of Technology Transfer – University of Michigan

An Electromagnetic MicroPower Generator for Low-Frequency Environmental Vibrations by Using Mechanical Frequency Up-Conversion

Technology #2714

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


Self-powered remote-controlled systems are frequently powered via batteries or fuel cells, or by drawing energy from ambient sources such as heat or light. Energy scavenging has recently become popular owing to its ability to produce clean power for sustained period of time. Among various energy scavenging sources, vibration has gained attention due to its abundance and several suitable scavenging techniques. While many of the traditional methods have been adapted to transform vibrational energy into usable energy, these approaches have faced difficulties at low frequencies, which is where most of the ambient vibrations exist and are available to be harvested.


Researchers at the University of Michigan have developed a micropower generator for producing electrical power from low frequency vibrational energy. The electromagnetic micropower generator up-converts low frequency environmental vibrations to a much higher frequency through a mechanical frequency up-converter, and hence provides efficient energy conversion even at low frequencies. This mechanical frequency up-conversion process can be achieved in a number of ways. Following frequency up-conversion, voltage is electromagnetically induced on coils mounted on resonators. Movement of the coils on their respective resonating cantilevers then generates voltage on the coils and energy conversion is realized.

Applications and Advantages


  • self-powered remote controlled microsystems in-nl-various applications including environmental and-nl-military


  • utilization of low frequency vibrations (1-100 Hz)
  • several up-conversion methods including-nl-electromagnetic, piezoelectric, or electrostatic