Stepper Motor

发布时间:2017-04-11 00:00
作者:Ameya360
来源:Ameya60
阅读量:1640

  Stepper motors utilize a doubly-salient topology, which means they have "teeth" on both the rotor and stator. Torque is generated by alternately magnetizing the stator teeth electrically, and the permanent magnet rotor teeth try to line up with the stator teeth. There are many different configurations of stepper motors, and even more diverse ways to drive them. The most common stator configuration consists of two coils (A and B). These coils are arranged around the circumference of the stator in such a way that if they are driven with square waves which have a quadrature phase relationship between them, the motor will rotate. To make the motor rotate in the opposite direction, simply reverse the phase relationship between the A and B signals. A transition of either square wave causes the rotor to move by a small amount, or a "STEP". Thus, the name "stepper motor". The size of this step is dependent on the teeth arrangement of the motor, but a common value is 1.8 degrees, or 200 steps per revolution. Speed control is achieved by simply varying the frequency of the square waves.

  Because stepper motors can be driven with square waves, they are easily controlled by inexpensive digital circuitry and do not even require PWM. For this reason, stepper motors have often been inappropriately referred to as "digital motors". However, by utilizing power modulation techniques to change the quadrature square waves into sine and cosine waveforms, even MORE step resolution is possible. This is called "micro-stepping", where each discrete change in the sine and cosine levels constitutes one microstep. Theoretically, there is no limit to the position resolution achievable with micro-stepping, but in reality, it is limited by the motor mechanical and electrical tolerances. Some stepper motors are designed specifically for micro-stepping, and consist of tightly matched impedances between the A and B coils, and tighter machining tolerances on the teeth, at the expense of higher cost.

  This animation demonstrates the principle for a stepper motor using full step commutation. The rotor of a permanent magnet stepper motor consists of permanent magnets and a stator which has two pairs of windings. Just as the rotor aligns with one of the stator poles, the second phase is energized. The two phases alternate on and off and also reverse polarity. There are four steps. One phase lags the other phase by one step. This is equivalent to one forth of an electrical cycle or 90°.

  This stepper motor is very simplified. The rotor of a real stepper motor usually has many poles. The animation shown here has only 10 poles, however, a real stepper motor might have 100. These are formed using a single magnet mounted inline with the rotor axis and two pole pieces with many teeth. The teeth are staggered to produce many poles. The stator poles of a real stepper motor also have many teeth, and are arranged so that the two phases are still 90° out of phase.This stepper motor uses permanent magnets. Some stepper motors do not have magnets and instead use the basic principles of a switched reluctance motor. The stator is similar but the rotor is composed of an iron laminate.

  Half Step Stepper Motor

  This animation shows the stepping pattern for a half-step stepper motor. The commutation sequence for a half-step stepper motor has eight steps instead of four. The main difference is that the second phase is turned on before the first phase is turned off. Thus, sometimes both phases are energized at the same time. During the half-steps the rotor is held in between the two full-step positions.

  This stepper motor uses permanent magnets. Some stepper motors do not have magnets and instead use the basic principles of a switched reluctance motor. The stator is similar but the rotor is composed of an iron laminate.

(备注:文章来源于网络,信息仅供参考,不代表本网站观点,如有侵权请联系删除!)

在线留言询价

相关阅读
  • 一周热料
  • 紧缺物料秒杀
型号 品牌 询价
MC33074DR2G onsemi
RB751G-40T2R ROHM Semiconductor
CDZVT2R20B ROHM Semiconductor
BD71847AMWV-E2 ROHM Semiconductor
TL431ACLPR Texas Instruments
型号 品牌 抢购
BP3621 ROHM Semiconductor
IPZ40N04S5L4R8ATMA1 Infineon Technologies
TPS63050YFFR Texas Instruments
ESR03EZPJ151 ROHM Semiconductor
BU33JA2MNVX-CTL ROHM Semiconductor
STM32F429IGT6 STMicroelectronics
热门标签
ROHM
Aavid
Averlogic
开发板
SUSUMU
NXP
PCB
传感器
半导体
相关百科
关于我们
AMEYA360微信服务号 AMEYA360微信服务号
AMEYA360商城(www.ameya360.com)上线于2011年,现 有超过3500家优质供应商,收录600万种产品型号数据,100 多万种元器件库存可供选购,产品覆盖MCU+存储器+电源芯 片+IGBT+MOS管+运放+射频蓝牙+传感器+电阻电容电感+ 连接器等多个领域,平台主营业务涵盖电子元器件现货销售、 BOM配单及提供产品配套资料等,为广大客户提供一站式购 销服务。