Mixed-Signal Sliding Mode Controller for Non-Inverting Buck-Boost Photovoltaic DC Optimizers

Photovoltaic (PV) dc optimizers require input voltage regulation over a wide range to maximize power extracted from PV panels. As such, seamless reference tracking and robust stability are required under all operating conditions. This work introduces a mixed-signal sliding mode controller for non-inverting Buck-Boost (NIBB) dc optimizers to address these challenges. The controller, implemented around a low-cost DSP platform, achieves seamless reference tracking in pass-through mode–where the input voltage is close to the output voltage–while retaining the reduced inductor and switch current stresses typical of multi-mode NIBB modulations. Design guidelines for the implementation are outlined, and experimental results validate the effectiveness of the proposed controller on a 600 W NIBB converter.