A harmonic excitation brushless synchronous machine has higher power density compared with the traditional aerial three-stage generator due to removing the axial exciter and is suitable for use as an integrated starting-generator (ISG). However, the field current cannot always be generated in the field windings at different rotor positions in the starting mode. A new excitation scheme employing double three-phase phase orthogonal zero-sequence armature currents is proposed in this article. Harmonic electromotive forces and field current can be produced by the zero-sequence rotating excitation magnetic field and almost has no relationship with the rotor positions. In addition, in order to obtain a constant field current during the starting process, a control method of the generated field current is also presented. The rotating speed and field intensity of the zero-sequence excitation magnetomotive forces are both feedback controlled by the zero-sequence current in the whole starting process. Comparing with the original harmonic excitation machine, a higher and more stable field current can be generated in the proposed ISG whenever the rotor is at any position or at a low speed. The prototype machine is manufactured and experiments are carried out together with the excitation control method to verify the effectiveness of the theoretical and finite element analysis results.

中文翻译：

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起动/发电机一体化双三相零序电流起动方案的设计与励磁控制


谐波励磁无刷同步电机由于取消了轴向励磁机，与传统的架空三级发电机相比具有更高的功率密度，适合用作集成启动发电机（ISG）。然而，在启动模式下，在不同转子位置的励磁绕组中并不总是产生励磁电流。本文提出了一种采用双三相正交零序电枢电流的励磁方案。谐波电动势和励磁电流可由零序旋转励磁磁场产生，与转子位置几乎无关。此外，为了在启动过程中获得恒定的励磁电流，还提出了产生励磁电流的控制方法。整个启动过程中，零序励磁磁动势的转速和场强均由零序电流反馈控制。与原来的谐波励磁机相比，无论转子处于任何位置或低速，所提出的ISG都可以产生更高、更稳定的励磁电流。制作样机并结合励磁控制方法进行实验，验证了理论和有限元分析结果的有效性。