Investigation of vanadium redox battery dynamics with a single-stage boost inverter for microgrid applications

Analytical results for the utilization of a single-stage boost inverter with a vanadium redox flow battery (VRB) are presented. The objective is to enhance the grid compatibility of renewable energy sources for ac microgrids. Single-stage boost inverters synthesize an output ac voltage that amplifies or attenuates its input dc supply voltage based on the duty cycle or modulation index command. The boost inverter operates as a single stage due to its simple and compact design which has a lower component count and improved reliability compared to the conventional multistage voltage source inverter. A sliding mode controller is employed to ensure robust and transient stability of the inverter in response to load changes. The chemical reaction kinetics of the VRB is included in the evaluation of the battery characteristics and is used to investigate the discharge mode of the battery when integrated with the proposed boost inverter for an energy storage system. Detailed simulation results confirm the benefits to microgrid operation when supplied from a VRB.