Last updated Nov 21, 2014
(Just a quick overview for now)
The Smart MPPT controller is based on a dual phase Buck switching power supply. With careful component selection, and attention to details, efficiencies should approach the 98-99% range.
Core of the hardware is a dual phase - 180o out of sync - buck converter. By utilizing a dual-phase approach, smaller inductors could be used, allowing off-the-shelf ones. And with the 180o out of phase, smaller filter capacitors are allowed.
The ATmegaxxM1 uC was selected to drive the FETs, taking advantage of its advanced PWM capabilities, as well as integrated CAN controller. Driving FETs hard and fast allow for very short dead-times, and when combined with a moderate 100Khz switching frequency, allow high efficiency of the conversion.
v0.0.1 of the PCB includes some components to enable debugging, also DC blocking capacities in the FET drivers (Protects the FET drivers in case of a burned out FET), as well as the ability to add ferrite beads in the FET gate drivers if needed to resolve spurious oscillations. It is expected the final version of the design will be able to remove these.