Maximum Power Point Tracking (MPPT) Techniques using Cubic Spline Interpolation – Perturb and Observe (P&O) for Partial Shading Conditions

Photovoltaic (PV) systems play an important role in achieving net zero energy and sustainable development, which normally require maximum power point tracking (MPPT) algorithms to be efficient. Due to the partial shading condition in a PV system, several local maximum power points (LMPPs) and a global maximum power point (GMPP) are mixed, preventing the PV system from achieving GMPP by applying normal MPPT techniques as these techniques treat one LMPP as GMPP and affect the output power. The study introduces an optimized MPPT technique for PV systems under partial shading conditions to address this issue. This novel hybrid MPPT technique takes advantage of the simplicity of Perturb and Observe (P&O) and the accuracy in transient responsiveness of the Cubic Spline Interpolation algorithm thereby ensuring more accurate tracking of the GMPP. This is achieved by constraining the tracking error allowance k to 5%, using 1 (100%) to subtract the ratio between the actual peak power and the previous P_max at GMPP. This enables determining whether environmental conditions have undergone a significant change (k>5%). Furthermore, it also ensures the non-oscillation performance at the global maximum power and the fast-tracking time of 0.24 seconds. This results in enhanced overall system efficiency. The study suggests further research on load dynamics, more complex configurations, and the confirmation of the practical applicability of the proposed method.