Optimal control for hybrid magnetically suspended flywheel rotor based on state feedback exact linearization model

Area of Science:

• Mechanical Engineering
• Control Systems Engineering
• Physics

Background:

• Hybrid magnetically suspended flywheel (MSFW) rotors utilize both active magnetic bearings (AMBs) and passive magnetic bearings (PMBs).
• The inherent nonlinear and coupled dynamics across different degrees of freedom (DOFs) pose significant challenges for control.
• Minimizing displacement runout and inter-DOF coupling is crucial for efficient operation.

Purpose of the Study:

• To develop and validate an optimal control strategy for a hybrid MSFW rotor system.
• To address the nonlinear and coupled dynamics in two controllable DOFs.
• To enhance the stability and reduce runout of the MSFW rotor at rated speeds.

Main Methods:

• Nonlinear dynamic functions of the hybrid MSFW rotor were developed using an equivalent magnetic circuit model.
• State feedback exact linearization (SFEL) was employed to linearize the nonlinear dynamic functions, minimizing DOF coupling.
• An optimal control strategy was designed based on the linearized SFEL model.

Main Results:

• The SFEL technique effectively reduced coupling between the two controllable DOFs.
• The designed optimal control strategy significantly reduced displacement runout at the rated speed.
• Simulation and experimental results confirmed the effectiveness of the proposed control method.

Conclusions:

• The SFEL-based optimal control is effective for hybrid MSFW rotors.
• The control strategy enhances rotor stability and reduces undesirable coupling and runout.
• This approach offers improved performance for magnetically suspended systems.