A Highly Integrated Resonant Coupled Brushless Electrically Excited Synchronous Motor Based on Winding Reuse and Dual-Frequency Coupling

The brushless excitation overcomes the speed limitations and low reliability of electrically excited synchronous motors (EESMs). However, existing brushless schemes still face challenges in simultaneously achieving high integration and high efficiency. This article presents a highly integrated resonant coupled brushless EESM (RCBESM) with an internally embedded brushless excitation structure. By reusing the stator winding and injecting dual-frequency currents, the fundamental component generates torque, while the high-frequency component resonantly transfers excitation energy to the rotor. Compared with the conventional brush and harmonic excitation EESMs, the proposed RCBESM achieves higher integration without external excitation hardware while maintaining the superior efficiency. The brushless excitation subsystem achieves an efficiency exceeding 80%, and the overall machine efficiency is improved by more than 0.4% compared with that of conventional harmonic excitation schemes. Finally, the experimental validation under high-frequency excitation regulation, dual-frequency torque generation, and variable speed/load conditions demonstrates that the proposed motor exhibits excellent steady-state efficiency and dynamic performance.