DAB-based Energy Storage System with Flexible Voltage Configuration and Extended Power Capability

Abstract

Product developments and requirements for wide operational voltage range of bidirectional power converters represent a technical challenge. To overcome the limitations of the current state-of-the-art, the proposed DAB-based converter topology employs a switch combination for parallel-series bridges configuration. The switching nodes of the low-voltage (LV) bridges are separately connected at the two transformer terminals. The dc ports of the two LV-bridges are interconnected through a switch interface which allows them to operate in a parallel-series fashion. The DAB-based converter with the switch interface doubles the voltage utilization range, which enables a broad range of applications for batteries (e.g., 48-V, 120-V). The MOSFET power devices within the DAB-based converter are used within their safe operation specification, while the proposed architecture allows flexible voltage configuration for different types of batteries. Furthermore, the proposed DAB-based converter extends the power capability of the converter to advantageously facilitate applications for energy storage systems (ESS). The experimental results have been performed using a 5kW nominal power DAB-based converter with silicon carbide (SiC) and silicon power MOSFET devices.