Application of Stepper Motor

Ⅰ.Application of Stepper Motor
At present, most of the stepping motors used in computer embroidery machines are 3-phase hybrid stepper motors, and the use of subdivision drive technology can greatly improve the running quality of the step motors, reduce torque fluctuations, suppress oscillations, reduce noise and improve step resolution.
1. The stepper motor is mainly used in some occasions with positioning requirements, such as: wire cutting worktable dragging, tufting machine work table (pore positioning), packaging machine (fixed length), basically it is used in occasions involving positioning.
2. The stepping motor has the characteristics of stable operation, low noise, fast response, long service life and high output torque. It is widely used in ATM machines, inkjet printers, plotters, photo machines, spraying equipment, medical instruments, computer peripherals, precision instruments, industrial control systems, office automation, robotics and other fields.
3.Stepping motors are widely used in textile machinery and equipment such as computerized embroidery machines. The characteristics of this type of stepping motors are that the torque is not high, the frequent start-up response is fast, the running noise is low, the operation is stable, the control performance is good, and the cost of the motor is low.
Ⅱ.Precautions for Stepper Motor Applications
1.The stepping motor is used in low-speed occasions---the speed does not exceed 1000 revolutions per minute, (6666PPS at 0.9 degrees), preferably between 1000-3000PPS (0.9 degrees), and it can be used here by a deceleration device. The motor has high working efficiency and low noise.
2.The stepping motor is best not to use the full-step state, and the vibration is greater in the full-step state.
stepper motor models
3.Due to historical reasons, only the motor with the nominal voltage of 12V uses 12V, and the voltage value of other motors is not the driving voltage. The driving voltage can be selected according to the driver (recommendations: 57BYG uses DC 24V-36V, 86BYG uses DC 50V, and 110BYG uses Higher than DC 80V). Of course, the 12V voltage can also be driven by other driving power besides the 12V constant voltage drive, but temperature rise must be considered.
4.For loads with large moments of inertia, a large frame motor should be selected.
complete stepper motor
5.When the motor is at a higher speed or a large inertia load, it is generally not started at the working speed. Instead, it uses a gradual frequency increase to increase speed. First, the motor does not lose step. Second, it can reduce noise and improve the positioning accuracy of stop.
6.For high precision, it should be solved by mechanically decelerating, increasing the motor speed, or using a high-division drive. A 5-phase motor can also be used, but the entire system is more expensive and has fewer manufacturers.
7.The motor should not work in the vibration zone, if necessary, it can be solved by changing the voltage, current or adding some damping.
stepper motor picture
8.The motor works below 600PPS (0.9 degrees) and should be driven by small current, large inductance, and low voltage.
9.The principle of selecting the motor first and then the drive should be followed.
Ⅲ.Circuit Diagram of Four Stepper Motors
Circuit Diagram 1:
The drive signal of the stepper motor must be a pulse signal! The speed of rotation is proportional to the frequency of the pulse. The step angle of this stepping motor is 7.5 degrees. A 360-degree circle requires 48 pulses to complete .
Group A coil corresponds to P2.4;
Group B coil corresponds to P2.5;
Group C coil corresponds to P2.6;
Group D coil corresponds to P2.7;
Forward rotation sequence: group AB - group BC - group CD - group DA (that is, one pulse, rotates forward 7.5 degrees).
Circuit Diagram 2:
The stepper motor has the characteristics of fast start and stop and precise positioning. In the field of digital control, the stepper motor is often used as the actuator of position control. In the fast operation of the stepper motor, the driving current provided by the driving circuit to the stepper motor winding is required to be as close as possible to the value required by its technical index to generate sufficient torque. Since the stepper motor is an inductive load, when the operating speed is increased, the power supply voltage must be increased to increase the working current of the winding. In practical applications, the control method often used is high and low voltage constant current chopper control.
The circuit consists of a speed discrimination circuit, an over-current and over-temperature detection circuit, A, B, and C-phase drive circuits and a power supply. In this circuit, there are A-phase drive signal (PA), B-phase drive signal (PB), C-phase drive signal (PC) and phase-locked drive signal (L) output by the single-chip microcomputer, all of which are active low. The high-voltage power supply for driving the stepping motor is supplied after AC70V rectification and filtering, and the phase-locked power supply is supplied after AC4.5V half-wave rectification. In addition, the circuit also requires DC voltages of +12V and +5V to be obtained by diode rectification and filtering of AC10V and AC5V. The power required by the digital circuit is provided by the host through the inter-board interface J401.
Circuit Diagram 3:
The output frequency and input voltage of LM331 have the following relationship: f0=Vi/(IRt1RL), where t1 is determined by the external timing components Rt and Ct, t1=1.1RtCt, IR is provided by the internal precision current source, IR=1.9V/RS, f0=ViRS/(2.09RtRLCt). RS is an adjustable resistance, and its function is to adjust the gain deviation of LM331. Ct is the filter capacitor, generally 0.01～0.1μF. In the case of a good filtering effect, a 1μF capacitor can be used. In order to improve accuracy and stability, components with low-temperature coefficients are used for the capacitor components.
Circuit Diagram 4:
BYG universal series two-phase stepper motors are most often designed with two drive circuits: unipolar and bipolar, which in principle reflects the control method of two-phase stepper motors, and increases the flexibility of stepper motor drive circuit design. The two-phase stepper motor's unipolar and bipolar drive circuit designs both use an online programmable single-chip AT89S52 as the controller, and a circuit composed of Darlington power tube TIP142 as the driver. The circuit structure is simple and the design is clear thinking.
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