Analysis of Unified Output MPPT Control in Subpanel PV Converter System

Photovoltaic (PV) systems frequently suffer disproportionate impacts on energy production due to mismatch cases. To remedy this, academia proposed a distributed max power point tracking (MPPT) solution and has been implemented commercially. Taking the trend of the “distributed MPPT” concept a step further, this paper discusses and analyzes an MPPT converter that connects to each PV cell string, called a subpanel MPPT converter (SPMC), to better address the real-world mismatch issues. The SPMC system with a unified output MPPT control structure is also proposed in order to reduce the cost and simplify the distributed MPPT system. The proposal saves A/D units, current sensors, and MPPT controllers on the premise of guaranteeing that the SPMC is working on its optimal maximum power point regardless of the mismatch case. This is favorable for the further integration and makes the whole SPMC system less expensive and easier to realize. Finally, the effectiveness of the proposal is confirmed experimentally.