Study On Elevator Traction Control Based On Switched Reluctance Motor Servo System

In modern building, elevator is important transportation equipment. Currently the vast majority of elevator traction motors are permanent magnet synchronous motors. Given the rare earth resource is a strategic non-renewable material, elevator industry needs urgently to develop special motor which can save energy and have superior control performance to replace permanent magnet synchronous motor. Switched reluctance motor doesn’t require permanent magnets made from rare earth materials. Also, it has advantages of simple structure, strong fault tolerance, small starting current, large starting torque and excellent control performance. Therefore, switched reluctance motor has a good prospect in the field of elevator.In this paper, servo control strategies of switched reluctance motor for elevator traction were studied, mainly including start-up modes based on zero state detection, curves of acceleration and deceleration, four-quadrant operation and anti-slip brake. Corrected starting powered logic was proposed on the basis of the capture of zero position signals from rotation transformer. This paper selected velocity curve of Parabola-Linear type as a reference curve and gave analytic equation of speed curve. Under the influence of closed-loop of speed, the actual speed followed the reference curve. Servo control system of switched reluctance motor for elevator traction has been designed with three loops, including outer position loop, intermediate speed closed-loop and inner current loop. According to elevator load characteristics and the rotor position, the motor were controlled in forward, reverse or braking state to achieve four-quadrant operation. Zero speed brake control strategy ensured that the motor halt and brake operation were in reliable convergence when the elevator stopped.Based on the above control strategies, experiment platform were founded with three-phase switched reluctance motor of12/8poles taken as control object, rotation transformer as position detection and TMS320F28335DSP as master chip. IGBT has been used to improve system reliability. Modular program design methods were taken to design the control software. In the experimental platform, smooth start, speed following, load operation, and anti-slip and zero speed braking have been achieved the expected results.