Research on Permanent Magnet Synchronous Motor Direct Torque Control Technology

　　Research on Permanent Magnet Synchronous Motor Direct Torque Control Technology
　　Direct torque control (DTC) is a new high-performance AC drive technology following vector control. More attention is paid to DTC in AC motor speed control area because of its advantages such as fast dynamic response,relatively simple algorithm and so on. With deep study of permanent magnet synchronous motor (PMSM), DTC strategy is applied gradually in PMSM control area. This paper is aimed at studying DTC technology deeply for PMSM.In order to make an neodymium prices accurate analysis for the principle of DTC, mathematical analysis of motors to be controlled is essential. So the operational principle of PMSM is analyzed firstly based on its structure in this paper, then mathematical models of PMSM are established under different reference coordinate systems.After that, the theory of DTC is studied deeply and traditional control system based on Bang-Bang mode is researched. The effects of space voltage vectors towards stator flux and electromagnetic torque are also analyzed. Due to existent disadvantages of traditional DTC mode, Space Vector Pulse Width Modulation is brought into PMSM DTC system in order to resolve the problems such as remarkable fluctuations of flux and torque. Moreover, the improved algorithm is griven for the harmonious control of stator flux http://www.999magnet.com/products/142-neodymium-prices and electromagenic torque.With Matlab6.5/Simulink the subsystems of traditional DTC system and SVPWM DTC system for PMSM are modeled and designed. Then the simulation models of the above two control strategies are also established. Iimitating actual control systems, simulation research is conducted and the experimental results are corresponding with theory analysis.The trend of motor control is total digitalization. In this paper, experimental platform for PMSM DTC system is designed baesd on TMS320LF2407A, and then concrete realization methods of software and hardware are shown. After experimental research, main experimental results are listed. The results prove that the control system is designed logically with high dynamic and static performance.