Design of magnetically levitated rotors in a large flywheel energy storage system from a stability standpoint

Abstract

The stability of flywheels in an energy storage system supported by active magnetic bearings (AMBs) is studied in this paper. We designed and built two flywheel energy storage systems (FESS) that can store up to 5 kWh of usable energy at a maximum speed of 18,000 rpm. One is optimized to store as much energy as possible, resulting in a flywheel with a strong gyroscopic coupling. The other has a much smaller gyroscopic coupling for ease of control. To analyze the stability of the system accurately, we derived the dynamic models of the rotor using finite-element method and integrated them with the models of the bearings, amplifiers, and sensors to obtain the simulation model of the system. We validated the model through experiments and compared the stability of these two systems.

Comparative Study of Performance of Switching Control and Synchronous Notch Filter Control for Active Magnetic Bearings

“…예를 들어 고강성의 지지가 필요한 가공 기 스핀들, (3) 불평형질량에 의한 진동제어가 필수 적인 플라이휠 에너지저장장치, (4) 초고속 진공펌프 등에 능동 자기베어링이 활용되었고, 그 적용 범 위가 확대되어 가고 있다. Tsiotras 와 Wilson (6) 은 바이어스 전류가 아예 없거 나 낮은 경우에 사용할 수 있는 비선형 제어기를 제안하였으나, 전압 포화의 문제점을 안고 있다.…”

Optimal Notch filter for active magnetic bearing controllers

“…A motor/generator is located below the flywheels. The system is designed to store 5 kWh of usable energy at the operating speed of 18,000 rpm in vacuum environment [5]. Table 1 shows specifications of the system and Fig.…”

Dynamic Characteristics Analysis of Magnetic Levitation Rotor Considering Unbalanced Magnetic Pull

“…Active magnetic bearings (AMBs) have the advantages of no wear, high rotation speed, and long life, and they can adjust rotor dynamics by active control-ling [1]. Thus, AMBs show incredibly high usage potential in rotating machinery [2,3]. However, AMBs have the supporting characteristics of 'negative stiffness', and their electromagnetic forces are nonlinear.…”