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。

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.

随着进入太空费用的不断增长，以及人类对安全性、可靠性和低成本达到太空的不断追求，人们开始关注新的进入太空的技术方法。电磁辅助发射技术的概念在于利用地面上的电能为火箭提供一个初始的速度，从而达到节省燃料、降低成本的目的。本文简要介绍了目前化学发射的不足之处和重接式电磁发射发射器的基本工作过程。重点分析了单级简单重接式发射器的基本性能，以及驱动线圈和板状发射体的参数对其基本性能的影响规律，为重接式电磁发射器的设计奠定了基础。在此基础上，结合简单重接式发射器的特点，提出一种新的多层、多级结构的电磁辅助推进系统并进行了仿真研究。结果表明利用此系统，可以将10000㎏左右的载荷以32倍的重力加速度加速到180m/s的速度，从而节省大量的发射成本。

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.