Adaptive Digital Synchronous P&O MPPT Algorithm for Photovoltaic DC Power Conversion

This paper presents an implementation of a new fast, robust and accurate Maximum Power Point Tracking (MPPT) technique for Photovoltaic (PV) applications. This algorithm uses an adaptive perturbation generator coupled with a synchronous data acquisition process. A variable offset is added to the perturbation in order to provide the control signal for the Digital Pulse Width Modulation (DPWM) stage that commands the switching of the DC/DC converter. Thanks to a Proportional Integral (PI) control of the offset variation, the overall dynamic behavior of the MPPT algorithm is enhanced by one order of magnitude. The adaptive control of the perturbation amplitude allows to minimize the steady state error of the MPPT algorithm, while insuring good operation at low power when the signal over noise ratio is poorer, this without the need of a high precision sampling system. This control strategy has been first validated through simulations. Experimental results are then demonstrated using a Boost converter with the presented advanced P&O MPPT control algorithm in real operating conditions for battery charging.