An Improved MPPT Approach Based on Analytical Inverter Input Impedance Computation for PV Water Heating Systems

An emerging type of photovoltaic (PV) system for which maximum power point tracking (MPPT) algorithms are scarce in the literature is the PV water heating system (PWHS). The application of existing PWHS-specific MPPT algorithms presents a significant difficulty in that none of them is able to provide, concurrently, low-complexity implementations and high tracking efficiencies. This paper addresses such challenge by proposing a novel impedance matching-based MPPT algorithm that has O(1)-complexity iterations and high efficiency for typical PWHS loads. Such efficiency improvement is achieved via generalization of a previous impedance matching algorithm, which is obtained by taking into account the effect of current harmonics into the impedance matching computations. The proposed algorithm is validated by means of simulation experiments, whose results confirm that it yields superior performance when compared to other low-complexity MPPT methods in the PWHS literature.