A Study Of Two-Phase Hybrid Stepping Motor Control System Based On DSP

As a key part in the field of automation, motion control technology based on motor plays an important role in the national economy. With the progress of modern science and technology, especially the integrated circuit, power electronics devices, automatic control theory etc, motor has developed from practical application of controlling rotation and stop and providing power to precise control of speed, acceleration,displacement and torque, so that driven mechanical motion consists with expectation accurately. As a digital control motor, stepper motor has the advantages of low cost,easy manipulation, high accuracy and no cumulative error. Stepper motor has been widely used in the numerical control device, servo system, printing and packaging equipment in the field of industrial automation.Stepping motor is an electromechanical actuator that convert electrical pulse signals to angular displacement and linear displacement. It receives the pulse control signals only,and it will not work properly with AC-DC power supply. Appropriate motor driver must be used to supply the pulse control signals. Therefore, a stepping motor and its motor driver is an indivisible whole, and the motor driver directly effects the performance of the motor.Space vector pulse width modulation(SVPWM) is a strategy that controls converter by switching AC space-voltage vector. It was proposed by foreign scholars in the 1980 s for the variable frequency drive of AC motor, meets the requirements of the circular air-gap magnetic field and aims at adjusting the AC motor flux space vector trajectory to approach circle. It has been proved that this method can reduce the torque ripple of the motor and improve the performance of the motor.Stepper motor torque vector control technology can improve the stability and amplitude of the output torque, and can greatly improve the dynamic characteristics and steady state performance of the motor. It is a new kind of stepping motor control strategy.Based on the DSP technology, the torque vector control strategy of two-phase hybrid stepper motor is the research emphasis of this project. This paper proposes a two-phase SVPWM control method based on three-leg bridge driver for the most widely used two-phase hybrid stepping motor in the current. The control principle and the method of determining parameter are introduced by the topology of the power circuit. Two-phase hybrid stepping motor is simulated by MATLAB/SIMULINK, and simulation model of space voltage vector pulse width modulation based on SVPWM control strategies is built. DSP is used as the main controlled unit, based on the two-phase three-leg SVPWM control theory, write a program combined with hardware circuit, enabling the two-phase SVPWM control.