A Family of Bidirectional DC-DC Converters for Battery Storage System with High Voltage Gain

In low power energy storage systems, to match the voltage levels of the low-voltage battery side and high-voltage direct current (DC) bus, a high voltage gain converter with bidirectional operation is required. In this system, the cost effectiveness of the design is a critical factor; therefore, the system should be designed using a small number of components. This paper proposes a set of bidirectional converters with high voltage gain range based on the integration of the boost converter with a Cuk converter, single ended primary inductor converter (Sepic), and buck-boost converter. The proposed converters consist of a small number of components with a high voltage gain ratio. Detailed comparisons are made with respect to the operating mode, number of components, voltage, and current ripple and efficiency. The efficiency of proposed converters are higher than the conventional converters in entire power range, and 6% higher efficiency can be achieved in large duty cycle by calculating loss analysis. To verify performances of the proposed converters, three 200-W prototypes of the converters are developed under the same experimental conditions. The results revealed that converter I exhibits the highest efficiency in the boost mode (92%) and buck mode (92.2%). The experimental results are shown to verify the feasibility and performances of the set of converters.