The Design And Implementation Of Inverter Based On Direct Torque Control System

With the widely use of AC machine in the modern social production, AC speed control system has become a hot issue, various frequency control strategies have emerged, among which the vector control and the direct torque control techniques are prominent.Compared to the vector control, direct torque control is simple, easy to implement and less dependent on the motor parameters. Because this system avoids the coordinate transformation and decoupling calculation, the impact of parameters have been reduced. The purpose of this paper is on the base of the direct torque control technique to realize the design and research of inverter.First, this paper introduces the development of AC speed control technology, and gives analysis on the current research situation of direct torque control system. Second, based on the motor model, related concepts of direct torque control system are introduced, and the operating principle of direct torque control system is analyzed. Considering the limitation of inverters’switching frequency and the control perfor-mance of system, the traditional six-sector model is divided into twelve-sector, and a control method has been proposed which can achieve the switching between the round flux and the hexagon flux. Next, the control system is simulated in the MATLAB/Simulink software, and the simulation results are given. Then, the hardware structure is introduced, it complete the whole control method in CCS software as C language. Additionally, in order to improve the accuracy of voltage detection, the difference of voltage detection is compensated in CCS software. Finally, through debugging the whole control system, the purpose of speed control is achieved, and signal waveforms during the experiment are analyzed.