June-Seok Lee and Kyo Beum Lee, “Variable DC-Link Voltage Algorithm with a Wide Range of Maximum Power Point Tracking for a Two-String PV System,” Energies, vol. 6, no. 1, pp. 58–78, Jan. 2013. -SCIE > Paper

This paper proposes a variable DC-link reference voltage algorithm for wide range of maximum power point tracking (MPPT) for

two-string photovoltaic (PV) systems. A multi-string system, which is a kind of PV system, is widely used due to its many merits (such

as the ability to use low rating devices, high MPPT efficiency, and so forth). PV systems can choose their input voltages on the basis

of their PV cell connection structure. The PV cell connection structure can be restricted because the input voltage and current affect

the PV system design. This reduces the MPPT range under some weather conditions. In the restricted PV connection structure, this

algorithm enlarges the MPPT range and minimizes the increment of the total harmonic distortion (THD) by selecting the appropriate

DC-link voltage reference which is changed by comparing the sorted input voltage. To verify the proposed algorithm, simulation and

experiments are conducted to show the results of the performance for the proposed algorithm.