Door Control System of Brushless DC Motor for Rail Transit Vehicle Using an Improved Flexible Motion Curve

Abstract

Door control system of brushless DC motor (BLDCM) for rail transit vehicle is described in this paper. A novel operation curve integrating time, speed and displacement is analyzed. In the conventional acceleration and deceleration method, the lag of motor speed response may lead to the problem of the significant impact when the door is closed. This paper describes an improved flexible acceleration and deceleration method, only using a few simple variables to adjust the shape of motion curve and reorganize the typical operation curve. It brings great convenience for the optimization of engineering practice. The current chopper based on the PWM cycle is realized by the hardware in this study, which can effectively limit the current. In this way, the output torque can be limited as well. This paper also analyzed the relation between the extrusion force and current chopping limits at the different motor speeds and motor speed at different current chopping limits to realize the safe and reliable control of the door. A controller based on TMS320F28335 is built to verify the previous analysis, corresponding software architecture is constructed as well. The experimental results verify the correctness and feasibility of the proposed method.