Abstract: Direct torque control was employed as the speed adjusting control strategy for mine electric locomotive based on the analysis of AC/DC speed adjusting methods.A deep theoretical study was made on the direct toque variable-frequency speed adjusting control system and a corresponding simulation model for mine electric locomotive was established by Simulink dynamic simulation tool in MATLAB.The simulation results show this system has a rapid torque response and good high speed performance.Based on this, an experiment platform of the speed adjusting system for mine electric locomotive was set up by a combined use of TI's TMS320LF2407DSP and IPM.The experiment results and the site testing indicate that this control system has the advantages of high traction force, good speed adjusting performance, easy maintenance and energy conservation.

Key words: Mine electric locomotive, Direct torque, Simulation model