Dynamic Modeling and Stability Analysis of a Hybrid Magnetic Bearing-Based Solar Array Drive Assembly

This paper presents dynamic modeling and stability analysis of a hybrid magnetic bearing (HMB) for a solar array drive assembly (SADA). A non-contact HMB using permanent-magnet bias and electromagnet control is considered to avoid friction, wear, and contamination in harsh environments. From an equivalent magnetic circuit, the magnetic force is derived and linearized at the nominal operating point using current and position stiffness. The results show that the HMB is open-loop unstable due to negative magnetic stiffness. A displacement-feedback stabilization condition is derived, and the closed-loop behavior is expressed with normalized control-authority and cross-coupling parameters. Simulations verify the instability, feedback stabilization, and tolerance bound for decoupled per-axis control.