This paper deals with an AC servo system with permanent magnetic brushless motor driven by square wave current.

研究了方波电流驱动的永磁无刷电机交流伺服系统。

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So, to use permanent magnetic brushless DC motor as the propeller of the ocean robot instead of the permanent magnet DC motor has a great significance both in theory and in practice.

因此，用无刷直流电动机代替永磁直流电动机作为海洋水下机器人的推进器，无论是理论上还是实际上都具有重大意义。

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Quantitative Determinding the distribution of magnetic field of permanent magnet brushless d. c. motor, is very important to analyze its properties.

永磁无刷直流电动机磁场分布的定量确定对电机性能的预测极为重要。

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