An extended voltage gain buck-boost converter for maximum photovoltaic power extraction

Abstract

ABSTRACT DC-DC converters are widely used in solar power systems to extract maximum power from solar photovoltaic (SPV) sources by matching the reflected load resistance to the internal resistance of the SPV source. This paper proposes a non-isolated buck-boost converter with extended range of voltage gain operating within practical limits of duty ratio. The gain of the proposed converter has been enhanced by lifting the voltage level of a classical buck-boost converter through a simple auxiliary network, comprising a semiconductor switch, an inductor and a capacitor. In the present work, the proposed converter has been used to extract maximum power from the SPV source with wide range of load resistance and under wide variation in solar irradiance and ambient temperature. Steady-state analysis of voltage gain, boundary condition analysis and design guidelines of the proposed converter have been presented in this paper. Finally, the theoretical analysis has been validated by experimentally verifying the performance of the proposed converter with a laboratory scale hardware prototype, tested with DSPIC33FJ32MC204 microcontroller for maximum power point tracking (MPPT) of SPV source. Real-time performance of the proposed converter has been found to match the predicted behaviour of the SPV system.