2-phase and 5-phase Stepper Motor Comparison
2 相和 5 相步进电机比较

You've narrowed your search for a motion control solution down to a stepper motor. Now it's time to decide, 2-phase or 5-phase? ORIENTAL MOTOR manufactures both 2-phase (1.8°/0.9°) and 5-phase (0.72°/0.36°) stepper motors and drivers. Our experience in both technologies gives us a unique perspective. ORIENTAL MOTOR has put together a quick feature-by-feature comparison to clear up the confusion and myths of the 2-phase versus 5-phase debate. The guide covers the basic differences between both technologies in the key areas of step motor performance: resolution, vibration, torque, accuracy and synchronism. ORIENTAL MOTOR's experienced Technical Support staff are also available for more in-depth explanations of both technologies.
您已将对运动控制解决方案的搜索范围缩小到步进电机。现在是时候决定了，2 阶段还是 5 阶段？ORIENTAL MOTOR生产2相（1.8°/0.9°）和5相（0.72°/0.36°）步进电机和驱动器。我们在这两种技术方面的经验为我们提供了独特的视角。ORIENTAL MOTOR对每个功能进行了快速的逐个功能比较，以消除2阶段与5阶段辩论的混淆和神话。该指南涵盖了两种技术在步进电机性能关键领域的基本差异：分辨率、振动、扭矩、精度和同步性。ORIENTAL MOTOR经验丰富的技术支持人员也可对这两种技术进行更深入的解释。

2-phase, 5-phase, what's the difference?
2相、5相，有什么区别？

There are two key differences between 2-phase and 5-phase stepper motors. The first is mechanical. A step motor consists of basically two parts, a stator and a rotor. The rotor in turn is made up of three components; rotor cup 1, rotor cup 2 and a permanent magnet. In a 2-phase motor the stator is made up of 8 magnetic poles with small teeth, while the 5-phase motor stator is made up of 10 magnetic poles. The poles in the stator are each provided a winding.
2 相步进电机和 5 相步进电机之间有两个关键区别。第一个是机械的。步进电机基本上由定子和转子两部分组成。转子又由三个部件组成;转子杯1、转子杯2和永磁体。在 2 相电机中，定子由 8 个小齿磁极组成，而 5 相电机定子由 10 个磁极组成。定子中的每个极点都有一个绕组。

The second difference between 2-phase and 5-phase is the number of phases. A 2-phase motor has two phases, an "A" phase and a "B" phase, while a 5-phase motor has five phases. Essentially, the number of phases refers to the different combinations of poles that are energized in sequence to attract the rotor.
2 相和 5 相之间的第二个区别是相数。两相电机有两个相位，“A”相和“B”相，而五相电机有五个相位。从本质上讲，相数是指按顺序通电以吸引转子的不同磁极组合。

2-phase and 5-phase Head-to-head
2 相和 5 相头对头

How do these differences affect performance? A number of factors are involved in the performance of a step motor. There are a number of ways to drive a stepper motor and the drive greatly affects the motor's performance. Wave Drive, Full Step, Half Step and Microstep are the most common drive methods and each offers very different performances. Without accounting for the various drive methods here are the key areas of performance for 2-phase and 5-phase stepper motors.
这些差异如何影响性能？步进电机的性能涉及许多因素。驱动步进电机的方法有很多种，驱动器极大地影响电机的性能。波形驱动、全步驱动、半步进和微步驱动是最常见的驱动方法，每种驱动方法都提供非常不同的性能。在不考虑各种驱动方法的情况下，这里是 2 相和 5 相步进电机的关键性能领域。

Resolution 分辨率

Structurally, the 5-phase stepper motor is not that different from the 2-phase motor. The rotor in both motors has 50 teeth. The difference is that because the 5-phase motor has 10 poles, 2 per phase, the rotor only has to move 1/10 of a tooth pitch to line up with the next phase. In the 2-phase motor, the rotor has to move 1/4 of a tooth pitch to line up with the next phase (8 poles, 4 per phase).
在结构上，5 相步进电机与 2 相电机没有太大区别。两个电机中的转子都有 50 个齿。不同之处在于，由于 5 相电机有 10 个极点，每相 2 个极点，因此转子只需移动齿距的 1/10 即可与下一相对齐。在 2 相电机中，转子必须移动齿距的 1/4 才能与下一相对齐（8 极，每相 4 极）。

This results in the 2-phase having 200 steps per rotation, 1.8° per step, while the 5-phase has 500 steps per rotation, 0.72° per step. The increased resolution of the 5-phase is inherent to its design. When coupled with a microstepping driver, the 5-phase motor can make steps as small as 0.00288°, however, position accuracy and repeatability are still subject to the motor's mechanical accuracy. The mechanical accuracy of both the 2-phase and 5-phase motor is ± 3 arc minutes (0.05°).
这导致 2 相每旋转 200 步，每步 1.8°，而 5 相每旋转 500 步，每步 0.72°。5 相的分辨率提高是其设计所固有的。当与微步进驱动器结合使用时，五相电机可以实现小至 0.00288° 的步进，但是，位置精度和可重复性仍受电机机械精度的影响。2 相和 5 相电机的机械精度均为 ± 3 弧分 （0.05°）。

Vibration 振动

Because of the smaller step angles in 5-phase stepper motors, 0.72° versus 1.8° in a 2-phase motor, the vibration in a 5-phase motor is much less than in a 2-phase. The graph to the right shows the vibration generated from a 5-phase motor versus the vibration generated by a 2-phase stepper motor. As you can see the 2-phase motor produces much more vibration.
由于 5 相步进电机的步距角较小，为 0.72°，而 2 相电机为 1.8°，因此 5 相电机的振动比 2 相电机的振动小得多。右图显示了 5 相电机产生的振动与 2 相步进电机产生的振动。如您所见，两相电机产生的振动要大得多。

*The graphs to the right represent microstepping at 5K steps per rev. These graphs were created by attaching a generator to a double shafted motor. As the motor vibrates the voltage generated was graphed. The more the motor vibrated the greater the voltage generated.
*右边的图表表示每转 5K 步的微步进。这些图表是通过将发电机连接到双轴电机来创建的。当电机振动时，产生的电压被绘制成图表。电机振动越大，产生的电压就越大。

Torque 力矩

While there is little difference between the output torque of a 2-phase stepper motor and a 5-phase stepper motor the 5-phase motor does have more "useable" torque. This is primarily due to the amount of torque ripple both motors produce.
虽然 2 相步进电机和 5 相步进电机的输出转矩差异不大，但 5 相电机确实具有更多的“可用”转矩。这主要是由于两个电机产生的转矩脉动量。

Half-stepping or microstepping a 5-phase stepper motor actually increases torque by up to 10% due to more phases being energized. 2-phase motors will lose torque by up to 40% when half-stepping and microstepping, however, many 2-phase drivers compensate by overdriving the opposite torque vector.
半步进或微步进：5 相步进电机实际上将扭矩增加多达 10%，因为有更多的相位通电。当半步进和微步进时，两相电机将损失高达 40% 的扭矩，但是，许多 2 相驱动器通过过驱动相反的扭矩矢量来补偿。

When the stator is energized it creates an electro-magnet which attracts the magnetic flux of the rotor. The magnetic flux can be broken into two vectors, one normal and one tangential. Torque is only produced when the tangential component is present. The presence of tangential flux is depicted in the illustration below.
当定子通电时，它会产生一个电磁铁，该电磁铁会吸引转子的磁通量。磁通量可以分为两个向量，一个是法向矢量，一个是切向矢量。只有当切向分量存在时，才会产生扭矩。切向通量的存在如下图所示。

In figure 1, the rotor teeth are directly lined up with the stator teeth and the flux only has the normal component so no torque is produced. As the rotor teeth are displaced from the stator teeth in figures 2, 3 and 4 the motor produces torque. We refer to this torque as negative because the torque is trying to pull the teeth back into the stable position. In figure 5, the flux is split evenly between the stator teeth and no torque is produced. By figures 6, 7 and 8 a positive torque is created as the displaced rotor teeth move to line up with the next stator teeth. Finally, the rotor teeth line directly up with the next stator teeth (figure 1).
在图1中，转子齿直接与定子齿对齐，磁通只有法向分量，因此不会产生扭矩。如图 2、3 和 4 所示，由于转子齿从定子齿移位，电机产生转矩。我们将这种扭矩称为负扭矩，因为扭矩试图将牙齿拉回稳定位置。在图 5 中，磁通量在定子齿之间均匀分配，并且不会产生扭矩。如图 6、7 和图 8 所示，当移位的转子齿移动以与下一个定子齿对齐时，会产生正扭矩。最后，转子齿直接与下一个定子齿对齐（图 1）。

Each phase of the motor contributes the sine-shaped torque displacement curve to the total output torque of the motor (illustrated below). The difference between the peak and the valley is called the torque ripple. The torque ripple causes vibration so the greater the difference, the greater the vibration.
电机的每一相都为电机的总输出扭矩贡献正弦形扭矩位移曲线（如下图所示）。峰值和谷值之间的差值称为转矩脉动。转矩脉动会引起振动，因此差异越大，振动越大。

With more phases contributing to the total torque of the motor, the torque ripple in a 5-phase motor is greatly reduced over a 2-phase motor. The difference between the peak and valley in a 2-phase motor can be as great as 29%, while a 5-phase is only about 5%. Since torque ripple contributes directly to vibration the 5-phase motor runs smoother than the 2-phase.
由于有更多的相位对电机的总转矩做出贡献，因此与两相电机相比，5 相电机中的转矩脉动大大减少。两相电机的峰谷之差可高达29%，而5相电机的峰谷之差仅为5%左右。由于转矩脉动直接导致振动，因此 5 相电机比 2 相电机运行更平稳。

2-Phase Torque Displacement
2 相转矩位移

5-Phase Torque Displacement
5 相转矩位移

Accuracy / Repeatability
准确性/可重复性

Accuracy has two components, electrical and mechanical. Electrical error is caused by phases being out of balance. For example, the motor's winding resistance has a spec of ± 10%, it is possible that although the motor is rated at 10W, one phase could be 9.2W and another phase could be 10.6W. This difference between the phases would cause the rotor to align more towards one phase than another.
精度有两个组成部分，电气和机械。电气错误是由相位不平衡引起的。例如，电机的绕组电阻规格为 ± 10%，但有可能虽然电机的额定功率为 10W，但一相可能为 9.2W，另一相可能为 10.6W。相位之间的这种差异将导致转子更倾向于一个相位而不是另一个相位。

There are several components to mechanical error, the major one is tooth configuration. Although the teeth on a motor are supposed to be square, the stamping process and age of the die can cause some of the teeth, or portions of the teeth to be rounded. Instead of the magnetic flux flowing directly, it can flow elsewhere when the teeth are rounded. So these factors contribute to the accuracy of the motor.
机械误差有几个因素，最主要的是齿形结构。虽然电机上的齿应该是方形的，但模具的冲压过程和年龄会导致一些齿或部分齿变圆。当牙齿变圆时，它不会直接流动磁通量，而是可以流向其他地方。因此，这些因素有助于提高电机的精度。

Using a Full-Step drive, a 2-phase motor repeats states every 4th step, while in a 5-phase motor the states repeat every 10th step. Any electrical error caused by imbalances in the phases is negated every 4th step in a 2-phase and every 10th step in a 5-phase, leaving only mechanical error.
使用全步驱动器，2 相电机每 4 步重复一次状态，而在 5 相电机中，状态每 10 步重复一次。在两相中每 4 步消除由相位不平衡引起的任何电气错误，在 5 相中每 10 步消除一次，只留下机械误差。

Once the motor completes a full 360° rotation, the same tooth is now lined up at the original starting point, eliminating mechanical error. Since a 2-phase motor takes 200 steps per revolution it is almost perfect every 200 steps, while the 5-phase motors take 500 steps per rev and are nearly perfect every 500 steps.
一旦电机完成完整的 360° 旋转，相同的齿现在就会在原始起点对齐，从而消除了机械误差。由于 2 相电机每转 200 步，因此每 200 步几乎是完美的，而 5 相电机每转 500 步，每 500 步几乎是完美的。

Synchronism 同期

Because the 5-phase stepper motor only moves 0.72° per step it is nearly impossible for the 5-phase motor to miss a step due to overshooting/undershooting. A motor will lose synchronism or miss a step when the teeth on the rotor don't line up with the correct teeth on the stator. What will cause the teeth not align properly? First, in order for a rotor tooth to not align properly another tooth must have aligned where it was supposed to. In order for this to happen the rotor must have either overshot (went past the correct stator tooth) or undershot (not moved far enough to line up with the correct stator tooth) by more than 3.6°. Why 3.6°? Well, because the rotor teeth are magnetically attracted, the correct tooth needs to be more than halfway between the teeth on the stator to align (7.2° between rotor teeth divided by 2 gives you 3.6°). So when the rotor overshoots the correct stator tooth by more than 3.6° the next tooth will align in its place, causing you to skip a step. Conversely, if the rotor fails to move more than 3.6° the current rotor tooth will remain lined up with the stator tooth and the rotor will not rotate, meaning you missed a step.
由于 5 相步进电机每步仅移动 0.72°，因此 5 相电机几乎不可能因过冲/过冲而错过任何一步。当转子上的齿与定子上的正确齿对齐时，电机将失去同步性或错过一步。什么会导致牙齿不能正确对齐？首先，为了使转子齿不能正确对齐，另一颗齿必须在它应该对齐的地方对齐。为了实现这一点，转子必须过冲（超过正确的定子齿）或下冲（移动得不够远以与正确的定子齿对齐）超过 3.6°。为什么是3.6°？嗯，因为转子齿是磁吸的，所以正确的齿需要在定子上的齿之间的一半以上才能对齐（转子齿之间的 7.2° 除以 2 得到 3.6°）。因此，当转子与正确的定子齿超过3.6°时，下一个齿将在其位置对齐，导致您跳过一个步骤。相反，如果转子不能移动超过 3.6°，则当前的转子齿将与定子齿保持对齐，转子将不会旋转，这意味着您错过了一步。

Drive Methods 驱动方式

There are a number of drive methods for both 2-phase and 5-phase stepper motors. Here is a quick overview of the concepts for Full-Step and Microstepping drives.
2 相步进电机和 5 相步进电机都有多种驱动方法。以下是全步进和微步进驱动器概念的简要概述。

2-Phase Full Step System (1.8°/step)
2 相全步进系统 （1.8°/step）

The 2-Phase Full Step system energizes both Phase A and Phase B and switches between positive and negative to create rotation.
2 相全步进系统为 A 相和 B 相通电，并在正负之间切换以产生旋转。

5-Phase Full Step System (Pentagon 4-Phase Excitation) (0.72°/step)
5 相全步进系统（五角大楼 4 相激励）（0.72°/步）

The 4-Phase Excitation System is unique to 5-Phase motors and offers more stable operation.
四相励磁系统是五相电机独有的，可提供更稳定的运行。

Microstepping 微步进

Microstep drivers divide the basic step angle of the motor by decreasing the current to one phase while increasing the current to the next phase in increments. This results in the motor taking smaller steps. With a microstep driver the motor’s basic step can be divided into smaller steps ranging from 1/1 to 1/250.
微步驱动器通过将电流减小到一相，同时逐步增加到下一相的电流来划分电机的基本步距角。这导致电机采取更小的步长。使用微步驱动器时，电机的基本步长可以分为较小的步长，范围从 1/1 到 1/250。

The illustrations to the right represent the basic concept of microstepping.
右边的插图代表了微步进的基本概念。

• Figure 1 - phase A is at 100% current so the rotor lines up directly.
  图 1 - A 相的电流为 100%，因此转子直接对齐。
• Figure 2 - the current to phase A is decreased to 75%, while 25% of the current is now in phase B.
  图 2 - A 相的电流降至 75%，而 B 相的电流现在为 25%。
• Figure 3 - the current for both phase A and B is 50% so the rotor lines up directly in the middle of the two.
  图 3 - A 相和 B 相的电流均为 50%，因此转子直接位于两者的中间。
• Figure 4 - phase A is now at 25% and phase B is at 75% so the rotor moves closer to phase B.
  图 4 - A 相现在为 25%，B 相为 75%，因此转子更接近 B 相。
• Figure 5 - phase A is turned off and phase B is at 100% so the rotor finally lines up directly with phase B.
  图 5 - A 相关闭，B 相处于 100%，因此转子最终直接与 B 相对齐。

By microstepping the motor in this example we have divided the basic 500 steps per revolution of the 5-phase stepper motor by 5, increasing it to 2,500 steps per revolution. The resolution of the motor is now 0.144°.
通过对电机进行微步进，在本例中，我们将 5 相步进电机每转 500 步的基本步数除以 5，将其增加到每转 2,500 步。电机的分辨率现在为0.144°。

Microstepping not only provides a higher resolution, it also ensures smoother operation, lower vibration and less noise than other drives.
与其他驱动器相比，微步进不仅提供更高的分辨率，而且还确保了更平稳的运行、更低的振动和更低的噪音。

Conclusion 结论

Depending on your particular application, a 2-phase motor may suffice. However, 5-phase stepper motors offer higher resolution, lower vibration, higher acceleration and deceleration rates (due to smaller step angles), and are less likely to lose synchronization due to overshooting/undershooting than a 2-phase stepper motor. For applications requiring high precision, low noise and low vibration, 5-phase is the better technology.
根据您的特定应用，两相电机可能就足够了。然而，与两相步进电机相比，5 相步进电机提供更高的分辨率、更低的振动、更高的加速和减速率（由于步距角较小），并且不太可能因过冲/下冲而失去同步。对于需要高精度、低噪声和低振动的应用，5相是更好的技术。

Want to learn more?

ORIENTAL MOTOR's Technical Support Team and Application Engineers will work with you to determine the best solution for your application. 2-Phase, 5-Phase, Full-Step, Microstep? ORIENTAL MOTOR's experienced team members know the technology inside and out. We'll find the right solution based on your needs and explain the alternatives. Call 1-800-GO-VEXTA (468-3982) to speak with an ORIENTAL MOTOR Technical Support Team Member.