High Step-Up Multimode Input-Parallel-Output-Series Power Optimizer for Wide-Range Photovoltaic Applications

This article introduces an efficient high step-up multimode input-parallel-output-series (IPOS) converter designed for wide-range photovoltaic applications. The proposed solution is based on the asymmetric splitting of the input power between a fixed-gain series resonant converter (SRC) used as DC transformer, and a synchronous boost operated in the boundary conduction mode, responsible for the gain modulation. The SRC includes a topology-morphing rectifier, which can be used as a voltage doubler or a voltage quadrupler according to the required voltage gain. The combination of the multimode and the partial power processing approaches allow to achieve a high efficiency on a wide range of operating powers and input voltages, overcoming the efficiency drop of resonant converters operating outside the resonance frequency. At the same time, the design flexibility offered by the IPOS architecture allows to achieve the best performance in the neighborhood of a desired rated voltage. Tests on a 700 W prototype validate the converter operation on the wide 15 V-45 V input voltage range, with an efficiency always above 90.5 %. The converter prototype exhibits a measured peak efficiency of 97.8 % and a California Energy Commission efficiency of 97.15 % at the rated voltage.