Permanent Magnetic Coupling Drivetrain Characteristic Analysis and Pole-slip Monitoring Strategy

Permanent Magnet Coupling (PMC) is commonly used in liquid or liquid-solid hybrid environments to connect loads such as turbines and blades. To address impact-induced pole-slip, this paper proposes a wide-frequency pole-slip state monitoring scheme for PMC that does not rely on load information, aiming to achieve precise pole-slip detection and rapid re-coupling. First, through experimental and theoretical analysis, the magnetic coupling transmission characteristics and critical stability conditions of the PMC drive-train are revealed. Then, focusing on the sinusoidal time-varying characteristics of pole-slip torque signal, an adaptive frequency monitoring module independent of closed-loop control is constructed. By combining frequency constraint boundaries with signal duration, a PMC pole-slip criterion without load information is established. Once a pole-slip signal is confirmed, the instruction planning controller will plan the speed commands within the torque constraint range to facilitate smooth re-coupling of the PMC drivetrain. Finally, the feasibility and effectiveness of the proposed monitoring scheme are verified through a magnetic coupling test bench.