Voltage-sensing-based photovoltaic MPPT with improved tracking and drift avoidance capabilities

Maximum power point trackers (MPPTs) are used to track the peak output power of the Solar photovoltaic sources. The maximum available power is tracked using specialized algorithms such as Perturb and Observe (P&O), which is an industry standard. The classical P&O algorithm requires the use of both voltage and current sensors. This algorithm has an inclination to drift away from desired operating point under rapidly changing atmospheric conditions. This classical algorithm also requires ad-hoc tuning measures at design time for selecting the right size of the search step. In most cost- and space-constrained systems, an algorithm with minimal sensing requirement, robust enough to cater to dynamic and steady-state requirements is desirable. The present work offers an algorithm involving simple computations and a single voltage sensor to arrive at and continuously track the maximum power point (MPP). In addition to eliminating drift during changing atmospheric conditions, the proposed method also provides self-tuning, variable search step that considerably improves dynamics and steady-state performance. A clear description and analysis of the algorithm is presented and verified experimentally on buck and boost converter topologies. (C) 2008 Elsevier B.V. All rights reserved.