Simulink Study Of Brushless Direct Current Motors Based On Direct Torque For Electric Car

With the global oil resource depletion and environmental pollution is increasingly serious in the context, research and develop of electric vehicles while be the important way of easy the energy crisis and the environmental pollution. In the key technologies of electric vehicles, motor control system is essential, it had been the hot research topic of domestic and foreign automobile manufacturers for a long time. And BLDCM (brushless direct-current motor) has the advantages of high efficiency, high control accuracy, high torque density, good heat dissipation, low-noise characteristics, and there is a large number of rare earth resources used in the manufacture of BLDCM in China. Therefore in this paper, we design a control system of electric vehicles based on direct torque control of BLDCM. The main contents are below.In this paper, we describes the electric car motors and control system based on apply status and performance requirements. Firstly, analyzed the structural characteristics of BLDCM, focus on the direct torque control algorithms, and build a mathematical model of direct control system of BLDCM.Then, establish a simulation model of direct control system for BLDCM in Matlab/simulink environment. And then test the performance of the model, analysis the phase A current waveform, the torque waveform, the speed waveform and the current waveform of the BLDCM. The result show that the performance of the model consistent with the actual.Finally, after the test of BLDCM model, we use the model for automotive vehicle simulink. Firstly, design and select the car’s drive train and drive motor parameters based on general automotive vehicle parameters and power indicators. Secondly, establish the vehicle traffic model under the Matlab/simulink environment, compelte the simulation experiment of constant speed driving on a good level of load, accelerating from rest to maximum speed, low-speed climbing, three typical driving conditions. Thirdly, analysis the phase A current waveform, the torque waveform, the speed waveform of BLDCM and the current waveform, the vehicle speed wave, the torque waveform, which gain from vehicle simulation under three kinds of conditions. The result show that the simulink system can well meet the performance requirements when we driving.In this paper, through the analysis of simulink result, compared with the electric vehicle application requirements, we know that the control system designed in this paper meet the application requirement, and proved the correctness of this method.