Maximum Power Point Tracking Algorithm for Photovoltaic Systems under Partial Shaded Conditions

摘要

The P-V characteristic of photovoltaic (PV) module under standard conditions (temperature and irradiation) presents one unique maximum, which can easily be tracked using conventional Maximum Power Point Tracking (MPPT) techniques. But under partial shading conditions, photovoltaic array exhibits several local maximum power points, only one of them is the global maximum. Therefore, the above techniques may fail to track the global maximum, reducing the extracted power as a result. The present paper deals with the problem of tracking the global maximum under different conditions. A new Perturb and Observe (P&O) modified algorithm is then presented. The algorithm monitors the maximum power point voltage and triggers a current-voltage sweep only when a partial shadow is detected, minimizing then the power loss due to repeated current-voltage sweeps.