Fast MPPT for Residential PV Systems with Low DC-Link Capacitance and Differential Power Processing

Tracking efficiency, cost, and reliability are important factors when selecting PV architectures and converter topologies. PV systems require power converters to maximize power extraction, for which DC-DC converters are a common choice. Differential Power Processing architectures can achieve higher efficiencies and lower cost by reducing the amount of power passing through these converters, while still providing Maximum Power Point Tracking (MPPT) capabilities. Single-phase grid connected PV systems, typical in residential applications, require a large capacitance in the DC bus to minimize the voltage ripple caused by double-line pulsating power, impacting the cost and reliability of the system. This work introduces a new MPPT mode of operation for flyback converters in DPP architectures. The proposed MPPT method shows extremely high dynamic performance and is capable of maximizing the power extraction even for highly variable bus voltages. In this way, the method enables a significant reduction in the DC bus capacitance, reducing costs and increasing reliability, while maintaining excellent tracking efficiency. The analysis is supported by mathematical procedures, and the system performance is validated by simulation and experimental results.