Least Component Count Off-Grid Solar Photovoltaic Scheme for Rural Household Application

Off-grid systems based on Solar Photovoltaic (PV) source have emerged as a promising solution for electrification in grid in-extensible areas. Major design challenges faced are requirement of: (a) operating PV at Maximum Power Point (MPP) to extract utmost possible power from the PV source, (b) protecting the battery damage due to over-charge and over-discharge, (c) converting the dc voltage obtained from PV side to requisite ac voltage with good efficiency, and (d) achieving the requisite voltage boosting operation in the system as using a low voltage battery and PV source is desirable for domestic application. As multiple requirements are to be met, majority of the previously worked-upon schemes for off-grid system required a minimum of three power converters involving several components leading to considerable system reliability and efficiency fall. A very few two-stage schemes are also proposed but they need higher component count clubbed to complex control. In an attempt to address this issue, a reduced component count off-gird system with only two stages, one bidirectional converter (BDC) and one dc-ac inverter followed by a step-up transformer is proffered. A suitable control strategy is also proposed. Matlab/Simulink platform is employed to validate the overall scheme, and relevant results are presented.