SimElectronics™

Stepper Motor - Model stepper motor

Library

Actuators & Drivers

Description

The Stepper Motor block represents a stepper motor. It uses the input pulse trains, A and B, to control the mechanical output according to the following equations:

where:

i_A and i_B are the A and B phase winding currents.
v_A and v_B are the A and B phase winding voltages.
K_m is the motor torque constant.
N_r is the number of teeth on each of the two rotor poles. The Full step size parameter is (π/2)/N_r.
R is the winding resistance.
L is the winding inductance.
B is the rotational damping.
J is the inertia.

If the initial rotor is zero or some multiple of (π/2)/N_r, the rotor is aligned with the phase winding of pulse A. This happens when there is a positive current flowing from the A+ to the A- ports and there is no current flowing from the B+ to the B- ports.

Use the Stepper Motor Driver block to create the pulse trains for the Stepper Motor block.

The Stepper Motor block produces a positive torque acting from the mechanical C to R ports when the phase of pulse A leads the phase of pulse B.

Basic Assumptions and Limitations

The model is based on the following assumptions:

This model neglects magnetic saturation effects, detent torque, and any magnetic coupling between phases.
When you select the Start simulation from steady state check box in the Simscape Solver Configuration block, this block will not initialize an Initial rotor angle value between –π and π.

Dialog Box and Parameters

Electrical Torque Tab

Phase winding resistance: Resistance of the A and B phase windings. The default value is 0.55 Ω.
Phase winding inductance: Inductance of the A and B phase windings. The default value is 0.0015 H.
Motor torque constant: Motor torque constant K_m. The default value is 0.19 N*m/A.
Full step size: Step size when changing the polarity of either the A or B phase current. The default value is 1.8°.

Mechanical Tab

Rotor inertia: Resistance of the rotor to change in motor motion. The default value is 4.5e-05 kg*m². The value can be zero.
Rotor damping: Energy dissipated by the rotor. The default value is 8e-04 N*m/(rad/s). The value can be zero.
Initial rotor speed: Speed of the rotor at the start of the simulation. The default value is 0 rpm.
Initial rotor angle: Angle of the rotor at the start of the simulation. The default value is 0 rad.

Ports

The block has the following ports:

A+: Positive electrical output of pulse A.
A-: Negative electrical output of pulse A
B+: Positive electrical output of pulse B.
B-: Negative electrical output of pulse B.
C: Mechanical rotational conserving port.
R: Mechanical rotational conserving port.

Examples

See the Controlled Stepper Motor demo.

References

[1] M. Bodson, J. N. Chiasson, R. T. Novotnak and R. B. Rekowski. "High-Performance Nonlinear Feedback Control of a Permanent Magnet Stepper Motor." IEEE Transactions on Control Systems Technology, Vol. 1, No. 1, March 1993.

[2] P. P. Acarnley. Stepping Motors: A Guide to Modern Theory and Practice. New York: Peregrinus, 1982.

[3] S.E. Lyshevski. Electromechanical Systems, Electric Machines, and Applied Mechatronics. CRC, 1999.