Performance of a magnetically suspended flywheel energy storage device

This paper describes a high-power flywheel energy storage device with 1 kWh of usable energy. A possible application is to level peaks in the power consumption of seam-welding machines. A rigid body model is used for controller design, stability, and robustness analysis. Flywheel systems tend to have strong gyroscopic coupling which must be considered in the controller design. The gyroscopic coupling can cause instability in addition with system nonlinearities, digitization, time delay, filter characteristics, and adaptive unbalance cancellation. Different approaches, such as decentralized control, controller design with a linear quadratic regulator (LQR), and cross feedback control are analyzed. Cross feedback control leads to a better system performance and is easy to implement. Experimental results are given. The startup behavior and the disturbing forces of the system while rotating are shown.