Advanced photovoltaic MPPT control method using an electromagnetic relay for solving the partial shade problem

The performance of a photovoltaic (PV) array is significantly reduced when cells or parts of the PV array are shaded. The partial shading does not only affect the power output of the PV array but also cause overheating. Setting up the PV modules in a low-cost configuration called the Shade-Relay (SR) is the best way to avoid the loss of the power output of the PV array. Therefore, in this paper an electromagnetic relay is used to wire the partially shaded modules in a configuration delivering more output power and creating only one peak on the PV output power characteristic. In addition, the conventional Maximum Power Point Tracking (MPPT) techniques such as hill climbing, Perturb and Observe methods should be modified to efficiently operate with the Shade-Relay for getting stuck with global maxima. The given data validated the effectiveness of the Shade-Relay configuration for the power recovery of the partially shaded PV array.