Transient stabilization of power grids using passivity-based control with flywheel energy storage systems

A novel passivity-based controller using three time-scale separations is introduced for variable speed drives of flywheel energy storage systems. The time-scale separation between the power electronics, the electrical machine variables, and the mechanical machine variables is used in order to design a nested three-layer controller. Since the dynamics of the variable speed drive are non-linear, the controller uses passivity-based control logic to achieve regulation of both the flywheel speed and the currents into the power electronics. Finally, the controller is demonstrated for transient stabilization of an interconnected power system in response to a large sudden wind generator disturbance.