The Study Of Step-Motor Driver With Wide Change Of Speed Control And Self-adaptable Subdivision

This dissertation is about one of a radar antenna servo carrying out machine fundamental researches,adopting the method of adaptive subdivision, step motor switching subdivision can not bring the sudden change speed when radar antenna high speed scouts and low scans ,step motor can lock up itself function when it stops with half of working current.The paper emphasizes the drive and control technology of stepping motor . This article analyzes the structure and the work principle of 2-phase hybrid stepping motor, establishes a nonlinear dynamic model, and also presents the expression of the winding flux linkage equation, rotation voltage equation, the rotor equation of motion and the transfer function.Based on the characteristics and the working principle of radar antenna requiring high scouting and low speed scanning ,the paper brings forward step motor driver with wide change of speed control and self-adaptable subdivision, which is based on current vector even rotation with constant amplitude.the way can controls step motor no surging and low yawp with running low frequency, not missing step with running high frequency, and step motor switching subdivision can not bring the sudden change speed.To control the exciting winding current and to produce rounded and even inner complex magnet field. The value of complex magnet field vector decides the value of motor torque; the neighboring two complex magnet field vectors decide the value of step angle.Through analyzing and establishing the subdivision model, this paper controls the winding current reasonably, and guarantees constant magnetic field value, even angle. A driver for 2-phase stepping motor is designed.The driver takes MCU AT89C51 as the control core, selects PBM3960 with 7 distinguish rates as subdivision's chip and the H-bridge LMD18245 as the driver circuit, the paper discusses the technology of driver, the hardware and software designing in detail.Using subdivision control technology, the motor operates smoothly, the operationprecision is increased and the torque is constant. the range of 8(2~n n for 0 to 7integer)...