Circuit topology study for distributed MPPT in very large scale PV power plants

In very large scale photovoltaic power plants (VLS-PV), due to partial shading and PV modules mismatching, a single point MPPT is not be efficient for all PV modules. Therefore, distributed maximum power point tracking (DMPPT) can be utilized to increase output power capability by increasing the number of converter/inverter units. In this paper, a simple circuit is introduced to achieve DMPPT. Then, the limitations of DC bus voltage, total output power, duty ratio of the different converter choices are discussed. Simulation results also show that the proposed strategy can be utilized to realize seamless transition between soft start mode and steady state operation.