A novel open-stator-winding DFIM flywheel architecture for renewable energy applications

Energy storage is becoming a basic component of modern renewable power plants, especially wind farms. For several considerations, local wind turbine (WT) energy storage is preferred. Flywheel energy storage is among the most promising storage systems regarded for wind applications. This paper proposes a new architecture for flywheel energy storage based on doubly fed induction machine (DFIM) where the open winding stator of the machine is connected in series between the grid and the wind turbine grid side converter. In this architecture, the flywheel-converter is of partial power rating, and is connected to the DFIM rotor. The paper proposes the control concept and thorough simulations test the performance parameters of the system under normal and abnormal operating conditions. Results and analyses indicate smooth dynamic operation, the economic advantage and the improved WT frequency support capability and fault ride through due to the proposed system.