无刷直流电机的核心在于其永磁同步电动机设计，电子部配备多相绕组，而转子则搭载永磁体。从结构上来看，无刷直流电机可以分为径向和轴向两种类型，再加上外转子和内转子的不同布局。此外，无刷直流电机的定子部分与一般交流异步或同步电机类似，其主要功能是创造磁路并固定多相绕组。常见的铁心设计都有齿槽，这样便于安装绕组。

另一方面，有刷直流电机也采用了无槽绕组技术，如无槽直流、无铁心、空心杯以及印刷线圈等型号。这一技术同样适用于设计无槽绕组的无刷直流电机，由于绕组直接在定子上进行制作，无刷直流電機無槽製作比有刷版本更为方便。此方法通常涉及自粘漆包线制造线圈，然后利用专用工具将它们排列到铁心表面并固化。在工作原理上，它与有齿槽结构相同，但由于特殊情况需要对其进行不同的方案设计。

与有齿槽结构相比，无槽结构带来了以下优势：

缺少齿轮产生的转矩，运行更加平稳且低噪声，这使得无槽设计尤其适合要求极致平顺运行环境。

电感极低，使得当当前入时能迅速增加，从而获得良好的机械特性和控制性。这种设计特别适合高速应用场景，其中速度可能达到（1-10）万次每分钟。

无须加工复杂环节，因此减少了损耗，并提高了效率。

然而，无slot design存在成本较高的问题，因为要实现所需强度的磁通密度需要更多永磁材料。大气隙中安装绕组增加了难度，而且生产过程中需使用专门设备，加之手工操作增添成本。另外，散热问题也是该类型引擎的一个挑战。

总结来说，无brush direct current motors employ a similar structure to general polyphase AC motors in terms of the winding configuration. The number of phases can vary from single-phase, two-phase, three-phase, four-phase, five-phase or more but three-phases are most commonly used in small engines as well as single phase in smaller applications. According to the average number of slots per pole occupied by each winding group and the number of layers per slot width, windings can be classified into integer-slot windings and fractional-slot windings; while based on the distance between two ends of a coil across different slots they are classified into full-pitch windings, short-pitch windings and long-pitch windings. The connection methods for these coils include star connections and enclosed connections though enclosed is less frequently used.

As for slotted reluctance motor production companies domestically are limited with Hebei Yudean Motor Co., Ltd offering a wide range product options that could be referred to.