Nonlinear Equivalent Resistance-based Maximum Power Point Tracking (MPPT)
Chaitanya Poolla& Abraham K. Ishihara
Carnegie Mellon University, Moffett Field, CA, United States

We present a nonlinear equivalent resistance tracking method to optimize the power output for solar arrays. Tracking an equivalent resistance results in nonlinear voltage step sizes in the gradient descent search loop that are significantly more uniform over the operating regime.  Further, we introduce a new model for the combined solar module along with a DC-DC converter which results in a highly nonlinear dynamical system due to the inherent non-linearity of the PV cell topology and the switched DC-DC converter system. To guarantee stability over a range of possible operating maximum power points, we utilize a feedback linearization control approach. Simulations are presented to illustrate the performance of the technique.

Area: Sub-Area 10.3: Maximizing Power Output On and Off the Grid