Abstract

Marine engine packages based on electric propulsion systems (EPSs) are highly reliable and improve the safety of vessel navigation. However, the currents consumed by an EPS with a capacity close to that of a vessel electric power plant contain upper harmonics and generate voltage distortion in the vessel mains. According to the International Association of Classification Societies, the total harmonic distortion coefficient of the vessel mains voltage curve must not exceed 8%. In the widely used structure of a unified vessel electric power system designed by Siemens AG, the required quality of voltage is attained by including high-capacity transformers in the EPS. This article shows how to ensure this quality of the vessel mains voltage by including multiphase generators in a vessel electric power plant. In this case, EPSs can be used without transformers, which allows making the electric equipment lighter, smaller, and cheaper. Multiphase generators also allow using three-level inverters as parts of frequency converters and reduce the share of upper harmonics in the phase currents of the electric propulsion motor, which will weaken the torque pulsation and increase the motor’s efficiency ratio.

中文翻译：

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改进专为电动船设计的统一数控电力系统的前景

摘要

基于电力推进系统 (EPS) 的船用发动机组件高度可靠，提高了船舶航行的安全性。然而，容量接近船舶发电厂的EPS消耗的电流包含高次谐波并在船舶电源中产生电压畸变。根据国际船级社协会规定，船舶电源电压曲线的总谐波畸变系数不得超过8%。在西门子股份公司设计的统一船舶电力系统的广泛使用的结构中，通过在EPS中包含大容量变压器来获得所需的电压质量。本文展示了如何通过在船舶发电厂中安装多相发电机来确保船舶电源电压的这种质量。在这种情况下，EPS 可以在没有变压器的情况下使用，这使得电气设备更轻、更小、更便宜。多相发电机还允许使用三电平逆变器作为变频器的一部分，减少电力推进电机相电流中高次谐波的份额，这将减弱转矩脉动并提高电机的效率比。