A fast and accurate maximum power point tracker for a multi-input converter with wide range of soft-switching operation for solar energy systems

Large solar farms generally require more than one central converter for the power conversion. Soft-switched multi-input converters (MICs) can be a good alternative to achieve higher efficiency and reduce the cost and size over the conventional approach in solar energy systems. Moreover, the power extracted from solar energy systems substantially varies with the change of the weather which ultimately reduce the efficiency of the system. An energy efficient method is required to locate the best operating point to capture the maximal amount of energy under different atmospheric conditions while maintaining soft-switching. This paper proposed a centralized maximum power point (MPP) tracking controller for a soft-switched MIC used in solar energy systems. The controller adopts the fixed perturb and observe method to reach MPP by varying the switching frequency of each input photovoltaic (PV) array in the converter. The controller is capable of maintaining zero voltage switching (ZVS) for both individual and simultaneous operations for a wide range of operating condition. Results are given on a 2kW solar system with varying irradiation intensity to highlight the merits of the work.