Product edit
The original model of the stepper motor originated in the late 1930s from 1830 to 1860. With the development of permanent magnet materials and semiconductor technology, the stepper motor quickly developed and matured. In the late 1960s, China began to research and manufacture stepper motors. From then until the late 1960s, it was mainly a small number of products developed by universities and research institutes to study some devices. Only in the early 1970s did breakthroughs in production and research. From the mid-70s to the mid-1980s, it entered the development stage, and various high-performance products were continuously developed. Since the mid-1980s, due to the development and development of hybrid stepper motors, the technology of China’s hybrid stepper motors, including the body technology and drive technology, have gradually approached the level of foreign industries. Various hybrid stepper motors Product applications for its drivers are increasing.
As an actuator, stepper motor is one of the key products of mechatronics and is widely used in various automation equipment. A stepping motor is an open-loop control element that converts electrical pulse signals into angular or linear displacement. When the stepping driver receives a pulse signal, it drives the stepping motor to rotate a fixed angle (ie, stepping angle) in the set direction. The angular displacement can be controlled by controlling the number of pulses, so as to achieve the purpose of accurate positioning. Hybrid stepper motor is a stepper motor designed by combining the advantages of permanent magnet and reactive. It is divided into two phases, three phases and five phases. The two-phase step angle is generally 1.8 degrees. The three-phase step angle is generally 1.2 degrees.

How it works
The structure of the hybrid stepper motor is different from that of the reactive stepper motor. The stator and rotor of the hybrid stepper motor are all integrated, while the stator and rotor of the hybrid stepper motor are divided into two sections as shown in the figure below. Small teeth are also distributed on the surface.
The two slots of the stator are well positioned, and windings are arranged on them. Shown above are two-phase 4-pair motors, of which 1, 3, 5, and 7 are A-phase winding magnetic poles, and 2, 4, 6, and 8 are B-phase winding magnetic poles. The adjacent magnetic pole windings of each phase are wound in opposite directions to produce a closed magnetic circuit as shown in the x and y directions in the figure above.
The situation of phase B is similar to that of phase A. The two slots of the rotor are staggered by half the pitch (see Figure 5.1.5), and the middle is connected by a ring-shaped permanent magnetic steel. The teeth of the two sections of the rotor have opposite magnetic poles. According to the same principle of the reactive motor, as long as the motor is energized in the order of A-B-A-B-A or A-B-A-B-A, the stepper motor can continuously rotate counterclockwise or clockwise.
Obviously, all the teeth on the same segment of rotor blades have the same polarity, while the polarities of two rotor segments of different segments are opposite. The biggest difference between a hybrid stepper motor and a reactive stepper motor is that when the magnetized permanent magnetic material is demagnetized, there will be an oscillation point and a step-out zone.
The rotor of a hybrid stepper motor is magnetic, so the torque generated under the same stator current is larger than that of a reactive stepper motor, and its step angle is usually small. Therefore, economical CNC machine tools generally require hybrid Stepper motor drive. However, the hybrid rotor has a more complex structure and a large rotor inertia, and its speed is lower than that of a reactive stepper motor.

Structure and drive editing
There are many domestic manufacturers of stepper motors, and their working principles are the same. The following takes a domestic two-phase hybrid stepper motor 42B Y G2 50C and its driver SH20403 as an example to introduce the structure and driving method of the hybrid stepper motor. [2]
Two-phase hybrid stepper motor structure
In industrial control, a structure with small teeth on the stator poles and a large number of rotor teeth as shown in Figure 1 can be used, and its step angle can be made very small. Figure 1 two

The structural diagram of the phase hybrid stepping motor, and the wiring diagram of the stepping motor winding in Fig. 2, the two-phase windings of A and B are phase-separated in the radial direction, and there are 8 protruding magnetic poles along the circumference of the stator. The 7 magnetic poles belong to the A-phase winding, and the 2, 4, 6, and 8 magnetic poles belong to the B-phase winding. There are 5 teeth on each pole surface of the stator, and there are control windings on the pole body. The rotor consists of a ring-shaped magnetic steel and two sections of iron cores. The ring-shaped magnetic steel is magnetized in the axial direction of the rotor. The two sections of iron cores are installed at the two ends of the magnetic steel respectively, so that the rotor is divided into two magnetic poles in the axial direction. 50 teeth are evenly distributed on the rotor core. The small teeth on the two sections of the core are staggered by half of the pitch. The pitch and width of the fixed rotor are the same.

Working process of two-phase hybrid stepping motor
When the two-phase control windings circulate electricity in the order, only one phase winding is energized per beat, and four beats constitute a cycle. When a current is passed through the control winding, a magnetomotive force is generated, which interacts with the magnetomotive force generated by the permanent magnetic steel to generate electromagnetic torque and cause the rotor to make stepwise movement. When the A-phase winding is energized, the S magnetic pole generated by the winding on the rotor N extreme pole 1 attracts the rotor N pole, so that the magnetic pole 1 is tooth-to-tooth, and the magnetic field lines are directed from the rotor N pole to the tooth surface of the magnetic pole 1, and the magnetic pole 5 Tooth-to-tooth, magnetic poles 3 and 7 are tooth-to-groove, as shown in Figure 4
图 A-phase energized rotor N extreme stator rotor balance diagram. Because the small teeth on the two sections of the rotor core are staggered by half the pitch, at the S pole of the rotor, the S pole magnetic field generated by the magnetic poles 1 ‘and 5′ repels the S pole of the rotor, which is exactly tooth-to-slot with the rotor, and the pole 3 ‘ And the 7′tooth surface generates an N-pole magnetic field, which attracts the S-pole of the rotor, so that the teeth face to teeth. The rotor N-pole and S-pole rotor balance diagram when the A-phase winding is energized is shown in Figure 3.

Because the rotor has 50 teeth in total, its pitch angle is 360 ° / 50 = 7.2 °, and the number of teeth occupied by each pole pitch of the stator is not an integer. Therefore, when the A phase of the stator is energized, the N pole of the rotor, and the pole of 1 The five teeth are opposite to the rotor teeth, and the five teeth of the magnetic pole 2 of the phase B winding next to the rotor teeth have a 1/4 pitch misalignment, ie, 1.8 °. Where the circle is drawn, the teeth of the A-phase magnetic pole 3 and the rotor will be displaced 3.6 °, and the teeth will be aligned with the grooves.
The magnetic field line is a closed curve along the N-end of the rotor → A (1) S magnetic pole → magnetically conductive ring → A (3 ‘) N magnetic pole → rotor S-end → rotor N-end. When phase A is powered off and phase B is energized, magnetic pole 2 generates N polarity, and the S pole rotor 7 teeth closest to it are attracted, so that the rotor rotates 1.8 ° clockwise to achieve magnetic pole 2 and rotor teeth to teeth, B The phase development of the stator teeth of the phase winding is shown in Fig. 5, at this time, the magnetic pole 3 and the rotor teeth have a 1/4 pitch misalignment.
By analogy, if the energization is continued in the order of four beats, the rotor rotates step by step in a clockwise direction. Each time the energization is performed, each pulse rotates through 1.8 °, which means the step angle is 1.8 °, and the rotor rotates once Requires 360 ° / 1.8 ° = 200 pulses (see Figures 4 and 5).

The same is true at the extreme end of the rotor S. When the winding teeth are opposite to the teeth, the magnetic pole of one phase next to it is misaligned by 1.8 °. 3 Stepper motor driver Stepper motor must have driver and controller to work normally. The role of the driver is to distribute the control pulses in a ring and amplify the power, so that the windings of the stepper motor are energized in a certain order to control the rotation of the motor. The driver of the stepper motor 42BYG250C is SH20403. For 10V ～ 40V DC power supply, the A +, A-, B +, and B- terminals must be connected to the four leads of the stepper motor. The DC + and DC- terminals are connected to the driver’s DC power supply. The input interface circuit includes the common terminal (connect to the positive terminal of the input terminal power supply). , Pulse signal input (input a series of pulses, internally allocated to drive the stepper motor A, B phase), direction signal input (can realize the positive and negative rotation of the stepper motor), offline signal input.
Benefitsedit
The hybrid stepping motor is divided into two phases, three phases and five phases: the two-phase stepping angle is generally 1.8 degrees and the five-phase stepping angle is generally 0.72 degrees. With the increase of the step angle, the step angle is reduced, and the accuracy is improved. This step motor is most widely used. Hybrid stepper motors combine the advantages of both reactive and permanent magnet stepper motors: the number of pole pairs is equal to the number of rotor teeth, which can be varied over a wide range as required; the winding inductance varies with
Rotor position change is small, easy to achieve optimal operation control; axial magnetization magnetic circuit, using new permanent magnet materials with high magnetic energy product, is conducive to the improvement of motor performance; rotor magnetic steel provides excitation; no obvious oscillation. [3]