Experimental Verification of a Magnetically Geared Generator for Backpack Energy Harvesting System

This paper verifies experimentally the performance of a magnetically geared generator for the backpack energy harvesting system (BEHS). A testbed is developed where the BEHS, consisting of a load frame, a main frame, a decoupling spring, and a walking person, is emulated using a linear actuation system. The linear actuation system is composed of a rotary PM machine coupled to a mechanical lead screw. The magnetically geared generator is formed by mechanically coupling a trans-rotary magnetic gear (TROMAG) to a rotary PM machine and is referred to as MITROMAG. The BEHS is run under optimum resistive damping to maximize the harvested power while limiting the backpack displacement for the user comfort and limiting the instantaneous power for reducing the system size. Dynamic friction of the test setup is obtained from experimental tests. When the effect of dynamic friction is considered in the analysis, experimental results closely match the analytical results.