Ambient energy exists in a wide variety of forms: vibration, strain and inertial forces, heat, light, wind and magnetic fields. Energy harvesting (EH) is the process of capturing and converting the ambient energy into usable electrical energy. Photovoltaic, piezoelectricity, thermoelectricity, inductive coils, and physical motion are some of the commonly used energy conversion approaches.

 

As more and more electronics systems emerge in all areas of our life, energy harvesting provides a promising way to satisfy their power needs. Energy harvesting can effectively improve the reliability and durability of the power supply systems, and is especially useful for portable electronic systems powered by batteries.  For example, soldiers in remote regions are highly dependent on electrical energy for communications, navigation and sensing.  Thus, there is a need for energy self sufficiency.

 

Archangel Systems, Inc. is developing a backpack generator system capable of generating electrical power while walking.   This system, called Intelligent ILBE Generator & Energy Management (I2GEM) system, harvests the energy of the mechanical movement of the backpack to generate electric power.  Thus, multiple batteries can be replaced by an energy harvesting system. Funding for this project is through a Small Business Technology Transfer (STTR) Phase I Award by the Office of Naval Research.

 

In I2GEM, a Vernier Hybrid Machine (VHM), which is integrated into the backpack frame, captures mechanical vibrations induced by walking and converts to electrical energy.  Magnetic gearing converts the slow physical velocity to a higher frequency flux, leading to a reduction in the size and weight of the generator.  An Intelligent Energy Controller (IEC) optimizes battery recharge routines to maximize efficiency as the ambient conditions, load levels and generator output vary.

 

A number of markets have been identified for application of I2GEM technology.  Different versions of this backpack could allow recreational hikers, disaster relief workers, explorers or soldiers to go out into the field with fewer heavy replacement batteries for cell phones, GPS instruments, night vision goggles and many other portable electronics. Refinements of the design could also lead to backpacks with increased comfort and lower stress on the back.

 

 

To support its Energy Harvesting R&D activities, Archangel Systems is also investigating Power Management (PM) technologies for both military and civilian markets.  Military applications include small UAV’s for persistent surveillance, dismounted soldier power and unattended ground sensors (UGS).

 

Archangel’s EH&PM effort, called SLOPE (System Level Optimization of Power and Energy) has three ongoing thrusts:  1) maintain a knowledge base of power management, energy harvesting and energy storage technologies including current state of the art and anticipated roadmaps, 2) identify and develop power train hardware for combinations of EH sources, batteries and loads, 3) develop models for EH&PM performance based on anticipated environmental conditions such as temperature, vibration and radiation.

 

Within the SLOPE framework, Archangel collaborates with other R&D interests early in their design cycles to provide two critical services.  First, EH&PM solution candidates are identified based on customer-driven constraints (size, weight, cost) and available technologies.  And second the requisite EH&PM subsystems are designed and delivered with seamless integration of hardware and software.  This allows our clients to focus on their expertise (UAV’s, mobile computing, etc.) while ensuring an optimized EH&PM strategy.