Modeling of a new multiple input converter configuration for PV/battery system with MPPT

For renewable sources, such as wind and solar energy, the generated voltages often vary because of environmental changes. When the input voltage drops to the value lower than the battery, it will fail to recharge. The cascaded buck-boost converters are conventionally used to step-up or step-down the input voltage, however it is relatively complex and costly. In this paper, a new battery charging system is proposed based on the noninverting buck-boost converters. The converter requires one less inductor and capacitor compared with the conventional buck-boost converters, thus the cost and loss are reduced significantly. The model is validated through the simulation results of one and multiple sources with constant and variable input voltages. Test results show stable operating performances on both steady-state and transit conditions. Maximum Power Point Tracking (MPPT) algorithm is also successfully applied to the proposed multiple input converter configuration. The proposed system is suitable for both low-voltage portable charging devices and grid-based battery bank systems.