Research On Efficient Permanent Magnet Synchronous Motor Drive And Control Systems For Electric Vehicle

Electric vehicle is more energy-saving and environmental protection,while, the traditional gasoline-powered cars consumed a great deal ofnon-renewable energy, and has resulted severely environmental pollution.Electric vehicles will take place of traditional cars sooner or later. Thedrive control technology of electric vehicle is one of key technology ofelectric vehicle technology.Firstly, electric car technology background has being introduced inthis article, then by comparative and analysis permanent magnetsynchronous motor (PMSM) has being chosen. PMSM has theadvantages of small volume, high power density, large output torque, etc,is a kind of ideal traction motor for electric vehicle drivers. However, theelectric car driving system with PMSM as drive motor has the followingtwo questions. First of all, the control algorithm is too complex, flux andtorque ripple when speed low. secondly, the system design are lesscomprehensive, some systems are too complex which cause a low powerdensity, others are too simple, which cause the motor can’t operated infour-quadrant, is not suitable for the characteristics of the electric carefficient drive. Aiming at these problems, this article mainly studies fortwo aspects: control method and hardware system.In the part of system design, Bi-directional DC-DC converter whichis very important but the most easily to be overlooked is researched. Thestudy included the selection of topology structure, the realization ofsoft-switching without ancillary circuit, the design of the main parameters,etc. Then, the main structure of the system was designed, and some of thehardware circuit and the software system was shown. Finally, theexperiment is done to the designed system. The experimental resultsshowed that the motor is smooth and quiet, the torque ripple is small and the dynamic and static characteristics is good, verified the feasibility ofthe system.In the part of PMSM control, the structure of PMSM, Commontransformation of coordinates and the mathematical model under eachcoordinate, the following research of Permanent magnet synchronousmotor control method bases on it. Then, the direct torque control (DTC)of the permanent PMSM’s Speed-sensor less Based on Space VectorModulation has being used to control drive motor. Finally, the ControlAlgorithm is verified by emulator. It turned out that the torque ripples aresmaller than it of traditional direct torque control, dynamic and staticcharacteristics are better and has good robustness, and the control methodis simple and reliable.