Procedure to match the dynamic response of MPPT and droop-controlled microinverters

Photovoltaic systems require the implementation of maximum power point tracking (MPPT) algorithms to maximize power extracted from these systems. However, the application of such algorithms in grid-connected droop-controlled systems is hampered by differences in the dynamic responses of the respective techniques. In this context, this study presents the development of a strategy that enables a push-pull converter controlled by MPPT and a low power plug and play grid-connected inverter governed by droop-control to operate stably even under variations in solar radiation and without any battery storage bank. The goal is achieved based on two approaches: (i) designing the DC link capacitor properly; (ii) using a control loop in order to adapt the droop curves in accordance with the available input power. Theoretical analysis and experimental results have proven the viability of the approach.