Stress Evaluation of Different Construction of Flywheel Energy Storage Systems using Double U-core Switched Reluctance Machine as its Driver

This paper deals with the stress analysis of various shapes of flywheel energy storage systems in conjunction with the double u-core switched reluctance machine. The inquiry is proposed according to the key factors in a flywheel layout including cost, material strength, energy storage capacity, mass and size of flywheel. The purpose of the study is to present a cost-effective flywheel with high efficiency of energy storage, in the absence of any expensive material and complex design. To this end, the analytical results of the tolerable rotational speed and its related amount of stored energy in an aluminum disk flywheel using double u-core switched reluctance machine as its driver has been first obtained. After ensuring the accuracy of the model by comparing the analytical results with those of numerical 3D CAD Workbench, different shapes of flywheel have been scrutinized to present a desired design for the flywheel to operate with high speed double u-core switched reluctance machine. In this investigation, the minimization of energy storage system cost and maximization of the stored energy are considered as the objectives. Moreover, the moment of inertia of the flywheel structure and the tolerable speed of the applied material used in the construction for preventing any failure are defined as the constraints.