Asynchronized Synchronous Motor-Based More Electric Ship—Less Power Electronics for More System Reliability

Nowadays, the fully power decoupled shipboard power system (SPS) architecture is popular. However, the volume of fragile power electronic converters is large, and the system overload capability is low. In this paper, an asynchronized synchronous motor (ASM)-based SPS is proposed for more-electric ships to handle these issues. The models of the simplified synchronous generator (SSG), ASM, back-to-back converter, and supercapacitor bank are established. Besides, the transfer function of the SSG excitation system is obtained, with the SSG stability analyzed. Moreover, an ASM control strategy based on the emulated stator voltage orientation (ESVO) without the phase-locked loop is proposed to control the ASM. By using the proposed ESVO scheme, the impacts on electric machines are mitigated by the effective SSG stator power control and ASM torque control. High quality of the three-phase voltage and current waveforms can also be obtained. Furthermore, the simulation study is carried out in MATLAB/Simulink to verify the performance of the proposed ASM-SPS. The proposed ESVO scheme and the conventional stator-flux-oriented control strategy are implemented, and the operation of an induction-motor-based SPS with grid voltage orientation is also illustrated for comparison, with frequent propulsion load variations taken into consideration.