The conquered another challenge, according to the university: driving down how much power the control circuit itself consumes.
The researchers made the system more efficient by using what the university called “an innovative dual-path architechture.” This means the system is able to build a up a charge in an energy-storage device (a battery or supercapacitor), which is customary – or it can bypass energy storage and directly power the device.
According to the abstract for the paper that describes the MIT research, published in the IEEE Journal of Solid-State Circuits, this dual-path architecture “has a peak efficiency improvement of 11%–13% over the traditional two-stage approach.”
The abstract also reports: “A proposed time-based power monitor is used for achieving maximum power point tracking for the photovoltaic harvester. This has a peak tracking efficiency of 96%. The peak efficiencies achieved with inductor sharing are 83%, 58%, and 79% for photovoltaic boost, thermoelectric boost, and piezoelectric buck-boost converters, respectively.”...