Research On The Control Strategies Of The Flywheel Energy Storage System

The flywheel energy storage system (FESS) is being taken more and more seriously due to its advantages of high energy storage density, high efficiency, and light pollution. Relying on the high speed rotating flywheel, the FESS realizes the transformation between power and kinetic energy by the electric power equipment, and thus to have a good application performance in fields like power control, load peak, uninterrupted power supply, etc. This thesis focuses on the FESS that works in the side of the dc bus, and does theoretical research in its working principle, equipment type selection, control strategy and then makes simulation analysis and experiment.This thesis chooses the permanent magnet synchronous motor (PMSM) as the flywheel drive motor and use vector control to realize the control under working conditions of power-driven and power-generation; at the same time, it helps PWM converter to finish the energy flow between the dc bus and the motor side. In the charging condition, the dc bus supplies the power, the PWM converter works as a inverter, and the control system drives the PMSM under subsection control strategy to accelerate the flywheel and store energy; in the discharging condition, the flywheel slows down because of its high inertia, the control system takes advantage of the inductance inside the motor and uses PWM converter as a booster, to get energy back to the dc side; meanwhile, the voltage regulation loop works, to ensure that the voltage of the dc side doesn’t fall.As a way to accomplish load peak, this thesis puts forward a plan to apply the FESS in oil rig system to help the equipment of dc side overcome disturbance; and the thesis puts forward a control strategy according to the actual demand; in addition, to expand the flywheel energy demand of the reservoir, this thesis does research in the flywheel storage systems running in parallel.The thesis establishes a model of the FESS in Matlab, as well as makes simulation and comparison of the control strategies and effects, in order to verify the correctness of the control strategy and the feasibility of the control scheme.Finally, the FESS experimental platform is designed and built, and experiment on charging and discharging the FESS is conducted, as to make further demonstration about the achievement of thesis.