The dc grid is emerging as a new electric power distribution concept for several types of vessels due to its higher fuel efficiency compared with the conventional ac grid. Until today, wound rotor generators (WRGs) and diode rectifiers have been applied to the generation part of the onboard dc grid although the efficiency, weight, reliability, and footprint of the WRGs are inferior to those of permanent magnet generators (PMGs). In this article, the possibility of adopting the PMG in the onboard dc grid instead of the WRG is studied. According to the analysis, even though the PMG is inherently incapable of adjusting rotor flux, the rectified dc voltage can be controlled in a certain range under all load conditions. Simultaneously, the diesel engine can be controlled near its optimal operating line (OOL) to minimize fuel consumption. The controllability of the rectified dc voltage of the PMG is verified by computer simulation and small-scaled experimental tests. When comparing the operating trace of the proposed system to the specific fuel oil consumption (SFOC) map of a 350-kW diesel engine, i.e., AD158TI, the fuel-saving by applying the PMG is expected to be more than 10% at light load condition and around 3% average in overall operating conditions.

中文翻译：

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永磁发电机与二极管整流器组合发电拓扑的海上直流电力系统


与传统交流电网相比，直流电网具有更高的燃油效率，因此正在成为多种类型船舶的新配电概念。直到今天，绕线转子发电机（WRG）和二极管整流器已应用于船载直流电网的发电部分，尽管WRG的效率、重量、可靠性和占地面积不如永磁发电机（PMG）。本文研究了在船载直流电网中采用 PMG 代替 WRG 的可能性。根据分析，尽管永磁发电机本身无法调节转子磁链，但在所有负载条件下，整流直流电压都可以控制在一定范围内。同时，柴油发动机可以控制在其最佳运行线（OOL）附近，以最大限度地减少燃油消耗。通过计算机仿真和小规模实验测试验证了永磁发电机整流直流电压的可控性。将所提出系统的运行轨迹与 350 kW 柴油发动机（即 AD158TI）的燃油消耗率 (SFOC) 图进行比较时，应用 PMG 预计在轻载时可节省 10% 以上的燃油总体运营状况平均水平约为 3%。