Stepper motors cannot achieve infinite speed change, but they can achieve a certain degree of speed change by changing the step angle and driving method.
- Working principle of stepper motor
A stepper motor is a motor controlled by different phases, which can achieve precise positioning and rapid acceleration and deceleration. The principle is to make the motor rotor rotate according to a fixed step angle under the changing phase sequence modulation. The movement of a stepper motor is discrete and can only produce a fixed step distance and cannot achieve seamless and continuous rotation.
- Definition and implementation of infinitely variable speed
Continuously variable speed refers to achieving stepless speed change by changing the motor output torque and speed. It can achieve very delicate adjustments, so that the motor’s speed and torque can be seamlessly switched, and almost any change can be achieved. There are two main ways to achieve infinite speed: frequency converter and speed regulator. The frequency converter uses the speed regulation function of the frequency converter to achieve stepless speed change, and the speed regulator realizes stepless speed change by adjusting the mechanical transmission ratio or changing the motor voltage flow.
- Reasons why stepper motors cannot achieve infinite speed change
Although stepper motors have great advantages in terms of accuracy and stability, due to their inherent motion discreteness, they cannot achieve stepless changes in motor output torque and speed, so stepless speed changes cannot be achieved. The speed of the stepper motor can only be adjusted by changing the pulse frequency and phase sequence, and the number of steps is also fixed, so the stepper motor has the defect of “step by step”.
- Change the step angle and driving mode to achieve a certain degree of speed change
Although the stepper motor cannot achieve infinite speed change, it can achieve a certain degree of speed change by changing the step angle and driving method. The smaller the step angle, the faster the motor rotates, and the larger the step angle, the slower the motor rotates. Therefore, changing the step angle can achieve a certain degree of speed change. In addition, driving methods such as open-loop control, closed-loop control, and micro-step control can also affect the motor’s speed and torque. For example, microstep control can be used to divide the step distance of a stepper motor into many small steps, thereby reducing the vibration of the motor and improving accuracy.
Conclusion
Although stepper motors cannot achieve infinite speed change, a certain degree of speed change can be achieved by changing the step angle and driving mode. Therefore, stepper motors are still an important driving method in automation fields that require fine positioning and rapid acceleration and deceleration.
