Degree Name

BS in Electrical Engineering


Electrical Engineering Department


David Braun


Cal Poly’s Energy Harvesting from Exercise Machines (EHFEM) project comprises of multiple subprojects seeking to effectively create a sustainable energy source through harvesting electrical energy generated from physical exercise machines. This project designs and implements a Buck-Boost DC-DC converter using a LT3791-1 4-Switch Buck-Boost Controller, replacing the previous SEPIC design. The DC-DC converter must operate within limits set by the maximum input range of the LT3791-1 controller. An input protection system prevents inputs higher than rated values, which may adversely damage the Buck-Boost DC-DC converter. These inputs include overvoltage transients, average voltage, and current output by the Precor EFX 561i elliptical generator. Therefore, integrating a modified version of Ryan Turner and Zack Weiler’s DC-DC Converter Input Protection System prevents system damage if generator outputs stray beyond safe operational range. This system also provides charge accumulation protection generated during an open-load phase during start-up of the Enphase M175 Micro- Inverter. Additionally, the DC-DC converter’s output must provide a voltage within the micro-inverter’s input voltage range to apply 240VRMS power back to the electrical grid.