Incorporating Saturation in Permanent-Magnetic Synchronous Generator Modeling for All-Electric Ship Applications

Increasing ship-board power demand coupled with environmental sustainability initiatives has created interest in pursuing all-electric ships (AES) for both commercial and military applications. AES can be equipped with power electronic components, loads, machines, and cables. Many electric generator topologies can be used for AES. To our best knowledge, permanent-magnetic synchronous generator (PMSG) is the most attractive solution because it is characterized by low maintenance levels, high compactness, and quiet operation. To evaluate, provide information, and guide technology selection, modeling and simulation of AES is required. This paper proposes an accurate PMSG model to analyze the dynamic characteristics of the generation system and to support system critical operations in the event of dynamic load change or component failure. Saturation in PMSG is modeled by means of analytical expressions, which can be easily embedded in equivalent-circuit models and which has some distinct advantages over look-up tables. The proposed model can be used in real-time control applications and in computer simulations. Four case studies are investigated through computer simulations with Simulink. From the simulations, it is found that the PMSG model has accurate performance as the variations of voltages and currents within acceptable ranges.