# Mathematical Modeling and Control for A Single Winding Bearingless Flywheel Motor in Electric/Suspension Mode

• Yuan, Ye (School of Electrical and Information Engineering, Jiangsu University) ;
• Huang, Yonghong (School of Electrical and Information Engineering, Jiangsu University) ;
• Xiang, Qianwen (School of Electrical and Information Engineering, Jiangsu University) ;
• Sun, Yukun (School of Power Engineering, Nanjing Institute of Technology)
• Accepted : 2018.04.06
• Published : 2018.09.01
• 227 38

#### Abstract

With the increase of the production of energy from renewable, it becomes important to look at techniques to store this energy. Therefore, a single winding bearingless flywheel motor (SWBFM) specially for flywheel energy storage system is introduced. For the control system of SWBFM, coupling between the torque and the suspension subsystems exists inevitably. It is necessary to build a reasonable radial force mathematical model to precisely control SWBFM. However, SWBFM has twelve independently controlled windings which leads to high-order matrix transformation and complex differential calculation in the process of mathematical modeling based on virtual displacement method. In this frame, a Maxwell tensor modeling method which is no need the detailed derivation and complex theoretical computation is present. Moreover, it possesses advantages of universality, accuracy, and directness. The fringing magnetic path is improved from straight and circular lines to elliptical line and the rationality of elliptical line is verified by virtual displacement theory according to electromagnetic torque characteristics. A correction function is taken to increase the model accuracy based on finite element analysis. Simulation and experimental results show that the control system of SWBFM with radial force mathematical model based on Maxwell tensor method is feasible and has high precision.

#### Keywords

Bearingless;Flywheel energy storage;Modeling method;Finite element analysis

#### Acknowledgement

Supported by : National Natural Science Foundation of China, China Postdoctoral Science Foundation

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