An Efficient and Cost-Effective Hybrid MPPT Method for a Photovoltaic Flyback Microinverter

This paper presents a grid-connected photovoltaic (PV) flyback inverter operating in discontinuous conduction mode (DCM) and controlled through an efficient, reliable, and cost-effective hybrid maximum power point tracking (MPPT) method. Although the proposed method can be applied to any grid-connected inverter topology, in this paper, it is applied on a modified flyback inverter circuit. Moreover, the proposed MPPT method is a two-stage scheme and hence, a hybrid solution, as it consists of a combination of fractional short-circuit current and hill climbing perturb and observe (P$\&$O) method reformulated. The change in weather condition is accurately detected using the current limit technique such that the difference in short-circuit current and photovoltaic current is monitored continuously. It is demonstrated that the use of current limit enables the system to swiftly track the maximum power point (MPP) in abruptly changing environmental conditions. The proposed MPPT method needs only two sensors for current and voltage measurements and is, therefore, cost effective and reliable. The system is tested through simulations and real-time setup using dSPACE DS1104. The results prove the effectiveness of the proposed hybrid MPPT compared with the P$\&$ O method under uniform and dynamic weather conditions.