Direct Torque Control System Study Of Speed Sensorless On DSP

In direct torque control (DTC) system, the concept of space vector is used to analyze the mathematic model of AC motor, the electromagnetic torque and flux are caculated and controlled in the stator reference frame, and the optimal PWM gating signals are generated to control the inverter according to the output of the dispersing regulator.The DTC technology is a high-performance speed method with fast torque response, while there are some questions, such as flux drift and torque ripple. To resolve these trouble, SVPWM subdividing voltage space-vector and tri-nod regulator and some measures such as stator' flux LPF, torque slide filtering are adopted. By these controls, the performance of system is improvedUsing Popov's criteria for hyperstability for designing a self-adaptive system, we devise a method to estimate the rotor speed based on MARS. The counter-electromotive force's observer with no speed's information can be regarded as a reference model of induction motor, while the counter-electromotive force's observer with speed's information is taken as an adjustable model. Taking into account the good convergence property and implementation in real system, we choose the MRAS as the close-loop of speed's measure to continue our experimentin real control system.The system software is designed in assemble language based on the TMS320F240 to implement the no sensor DTC algorithm. The experimental results indicate that the system has stable performance , so to some extent it is practical useful system.