Research of Electric Vehicle IM Controller Based On Space Vector Modulation Direct Torque Control

Direct torque control (DTC) can allows the precise and quick control of IM flux and torque without calling for complex algorithms, which requires only the knowledge of the stator resistance. But bang-bang control algorithm also brings out great current harmonics and electromagnetism noise, which confines its applications in electric vehicle. The tutorial starts by reviewing the basic operation of IM and a PWM inverter using the space vector theory. Then the concept of DTC is illustrated, including switching table (ST), direct self-control (DSC) and merits and limits of a DTC are reported. Next stator flux vector control strategy is introduced, which uses for reference DTC´s stator flux observator´s method. At last a DSP card with TMS320VC33 at 60 MHz is used to implement algorithms described above. An IGBT inverter is used to drive IM. Experiment shows torque ripple is small in modified DTC, which fits for EV motor´s control