本文针对不对称气隙小功率单相永磁无刷直流电动机定位力矩的计算问题建立了两种数学模型，用解析的方法对定位力矩进行了定性的分析，用有限元方法进行了实例计算。并用实验方法进行了验算。

由于传统的抽油机系统可控性能差、效率较低，文中研究了代替传统旋转电机用的直线无刷电机，对其电机本体和电机驱动进行分析，研制了具体的模型和驱动系统。

随着航空、航天技术的发展，提出了在各类航空、航天飞行器上用电动执行机构取代液压执行机构的课题，以克服液压执行机构存在的体积和重量大，结构复杂，成本高，可靠性差等缺点。本文提出了一种多层气隙平板式的直流直线电动机结构，比较好地解决了此类电动机所要求的高推力，体积比的问题。

In order to measure the pulse high current in the RCEML accurately, a Rogowski coil has been design in the paper, and its principle has been analyzed. Next, the effects on parameter (the resistance, inductance) of Rogowski coil due to the current change are analyzed. Because of the particularity of coil current in the RCEML, self-integrating connection mode is adopted. Last, the fluctuant course of signal and signal distortion in the transmission line are analyzed, the way to reduce the signal distortion is presented, and the relative experiments have been performed.

Because induction motor that modulates its speed by the frequency has wide transfer speed range, high systematic efficiency, simple structure and long life, it becomes one of the best choices in the driving motors used in electrical vehicle. In present, the research trend of it is inclined to high power, high speed, high efficiency and long life. How to meet the above requirement by using the electromagnetic design, structure design and heat design, becomes a matter that needs to be resolved now. In this paper, the characters of the motor in the operation are analyzed, all kinds of factors that relate to life are laid out, its heating and loss are discussed and analyzed. The key reasons affecting the motor life are presented, and different characters of the high induction motor compared with general induction motor are reported. A design idea is described, that is: we should consider how to improve the efficiency and reliability as well as how to reduce the heating by change the electromagnet, structure, dissipation and operation of the motor. How to reduce its losses and to improve its dissipation has been presented in the paper, the result is feasible.