An additional DC-DC boost converter is used in conventional configuration of Flywheel Energy Storage System (FESS) to regulate the output voltage during flywheel low speeds. This paper presents a new FESS based on the boost inverter topology. The proposed system facilitates voltage boost capability directly in single stage. A three-phase boost inverter consisting of three DC-DC boost converters is employed in this paper. The main advantage of the boost inverter is the deployment of only six switches and undersized passive elements to obtain a boosted up AC output voltage weighed against the input DC supply. The boosting capability of boost inverter is also verified experimentally in this paper. The boost inverter in Flywheel Energy Storage System is modeled and simulated using MATLAB/SIMULINK.