Electromagnetic Synchronous Motor Direct Torque Control System

Compared to Permanent Magnet Synchronous Motor, The magnetic field of rotor of Electrical-Magnet Synchronous Motor is generated by excitation coil, which makes Electrical-Magnet Synchronous Motor have excellent performance such as high power density, high efficiency and free maintenance. So it plays an important role in the domain of driving motion. The Direct Torque Control (DTC) has been another advanced control method besides the current vector control, and it has been applied in synchronous motor in recent years. The control system of Direct Torque Control in Electrical-Magnet Synchronous Motor has several advantages as follows compared to PMSM: because of the difference in architecture, the amplitude of stator flux linkage is not confined by rotor flux linkage; and it controls the stator flux linkage directly, that makes it easy to drive the motor without the application of sensors. So it is valuable to develop the research of Direct Torque Control system in Electrical-Magnet Synchronous Motor.In this dissertation, the Direct Torque Control ( DTC ) system for sensorless Electrical-Magnet Synchronous Motor is studied profoundly. Based on the research of limitation of classical DTC system, the sensorless Synchronous Motor system of Direct Torque Control has been designed, and the digital signal processor (DSP) is used to implement this system.Based on the classical DTC inherent limitation, the SVPWM and DTC are combined to reduce the torque fluctuation, by sending more voltage vectors to approach actual vector. The switching table is improved and optimized by the investigation of the influence of different vector to the torque variation, and a flux and torque two-level switching table is taken. Simulation and experimental results show that the torque of the motor can be improved largely without degrading dynamic performance of system, and the torque ripple is weakened greatly.In the sensorless control system, a specified high frequency signal is injected in to trace the magnetic anisotropy of the motor, by which we can get the value of rotor speed and position. The estimation of the rotor initialization position is also discussed. Results show that the system can achieve good accuracy with this technique.In the end, accomplishing the control system with TMS320VC33 DSP, and writing the real-time controller software by C mixed with Assemble language. By which many high performances is attained.