Active Disturbance Rejection Control for a Flywheel Energy Storage System

This paper presents the application of the Active Disturbance Rejection Control Technique (ADRCT) to improve the performance of a Flywheel Energy Storage System (FESS). The FESS is designed for the DC MicroGrid (MG) application. It mainly consists of a flywheel with a coaxial BrushLess DC (BLDC) machine, a three-phase full-bridge circuit, and a bidirectional Buck-Boost converter. A model-independent controller based on the ADRCT, which can estimate and compensate model uncertainties and unknown disturbances in real time, is designed for the bidirectional Buck-Boost converter control in the FESS. Simulations and experiments are conducted in both charge and discharge mode to verify the performance of the proposed controller by comparison with a traditional double loop PI controller. Results show that the new controller is more robust and more adaptive. It has a better anti-disturbance capability and a higher dynamic performance than the PI controller. Moreover, to adapt to different applications and operating conditions, the charging process of the FESS is further improved. Strategies on maximum torque control and power limiting control are developed and realized on the experimental platform.