Analytical model-based analysis of high-speed Flywheel Energy Storage Systems for pulsed power applications

In this paper, performance of an advanced high-speed Flywheel Energy Storage System (FESS) for pulsed power applications using analytical models derived in synchronous d-q Reference Frame (SdqRF) is investigated. The principal nonlinear model being used was derived in the previous works without any simplifying assumptions and can be used for any type of studies. Applying state space averaging approach to the non-linear model, dc and small-signal ac models of the high-speed FESS were derived. In this paper, these models are used to evaluate the performance of the FESS in both dc and small-signal ac modes of operations. For dc analysis, the FESS is charged from low speed to high speed and is discharged and the performance of the FESS is evaluated over complete operating range. Then, the small-signal models are developed at these dc operating points and the small-signal ac analysis is performed. This comprehensive investigation will provide a valuable database for control engineers to make an informed decision on both type and design of the controller. At the end, as a proof of the accuracy of the model, the analytical results are compared with simulation results using PSIM package.