The principle of stepping motor
A stepper motor is an actuator that converts electrical pulses into angular displacement. When the stepper driver receives a pulse signal, it drives the stepper motor to rotate a fixed angle (called "step angle") in the set direction, and its rotation runs step by step at a fixed angle. The angular displacement can be controlled by controlling the number of pulses, so as to achieve the purpose of accurate positioning; at the same time, the speed and acceleration of the motor rotation can be controlled by controlling the pulse frequency, so as to achieve the purpose of speed regulation. The stepper motor can be used as a special motor for control, and it is widely used in various open-loop controls by taking advantage of its characteristics of no accumulated error (100% accuracy).
The more commonly used stepper motors include reactive stepper motors (VR), permanent magnet stepper motors (PM), hybrid stepper motors (HB) and single-phase stepper motors.
The rotor inside the servo motor is a permanent magnet. The U/V/W three-phase electricity controlled by the driver forms an electromagnetic field. The rotor rotates under the action of this magnetic field. At the same time, the encoder of the motor feeds back the signal to the driver. Values are compared to adjust the angle at which the rotor turns. The accuracy of the servo motor depends on the accuracy (number of lines) of the encoder.
A stepper motor is an open-loop control element that converts electrical pulse signals into angular displacement or linear displacement. In the case of non-overload, the speed and stop position of the motor only depend on the frequency and number of pulses of the pulse signal, and are not affected by the load change, that is, add a pulse signal to the motor, and the motor will turn a step angle. The existence of this linear relationship, coupled with the characteristics of the stepping motor only has periodic errors but no cumulative errors. It makes it very simple to use stepping motors to control in the control fields such as speed and position.
Although stepper motors have been widely used, stepper motors are not like ordinary DC motors, and AC motors are used routinely. It must be used by a control system composed of a double-ring pulse signal and a power drive circuit. Therefore, it is not easy to make good use of stepper motors. It involves many professional knowledge such as machinery, motors, electronics and computers.
