Analysis Of AC Step Motion Drive And It's Discrete Control

AC step motion drive is a new research branch with the development of the motion control. It is a new-style method of the drive control fed by static transducer in the control of the microcomputer, which makes the stator flux movement discrete. And position and speed outputs can be achieved on the motor axes. Stepping drive of synchronous motors, upgrading the design idea of stepping motors from combined electromagnet theory to rotary magnetic field theory, will make the capability and efficiency of the increment control system improved to a new level, which is the research purpose of AC step motion driveThis paper begins with the direct torque control method for PMSM to expatiate AC step motion control theory distinctly. First, a PMSM direct torque control method based on SVPWM is studied. And a good control effect of the flux and the torque is gained according to selecting the six voltage space vectors. And in simulation, this control method consider the circs that the angle between the stator and the rotor is bigger than 90 degrees, which restrains steps losing of synchronous motor effectively. Second, A direct torque control for PMSM Based on stepping SPWM is analyzed. In classic DTC system, the torque and current ripples are larger because of the restriction of the number of voltage vectors. By means of the vectors subdividing theory, using a new method of dividing voltage vectors based on stepping SPWM, more voltage vectors on a circle in space can be achieved. And voltage vectors can be selected more effectively. By theory analysis and simulation research, the proposed control method is feasible, and can diminish the torque ripple.It can be seen from DTC space vectors whose flux linkages are discrete in space that the DTC method is also a discrete control approach for motor drives, which is consistent with AC step motion control in control ideology. But in DTC control, fast torque response and speed performance are the final objective, which can not achieve position control of synchronous motors. And then the dissertation of AC step motion control is coming. In this paper point to point control, constant frequency control and up and down frequency control are studied, in which current lagging loop control method is used to restrict over currents. And using flux tracking method, position open loop, position close loop control system are also studied. Andresearch results indicate that larger current ripples are restricted by means of subdividing space vectors. To testify the feasibility of the scheme, the scheme is simulated by the dynamic simulating tool SIMULINK of MATLAB6.0 software, and the static and dynamic performances are analyzed. And a stepping control system is composed based on TMS320F240 digital signal processor. Then some experiments are performed.The simulation and experiment results indicate that this system not only is feasible, but also is of fine speed and position control ability and has broad developing prospects.