Research On Permanent Magnet Synchronous Motor Speed Control System

Permanent magnet synchronous motor has features of small size, light weight, high efficiency and high power factor. It is well received by the researchers in the world. The motor application areas have been constantly expanding, which include high-precision machine tools, electric vehicles, inverter air conditioner and so on. At the same time, the reserves of rare earth resources in China ranks first in the world, which have aslo played a great role in promoting the development of permanent magnet synchronous motor in our country. Researching the high-performance permanent magnet control system has become a realistic and very urgent in order to adapting to the development of industrial economy. With the study of permanent magnet synchronous motor, focusing on the problem of PMSM vector control and speed sensorless, this thesis has done the following work:(1) This article firstly introduces the physical structure of the permanent magnet synchronous motor and the coordinate transformation theory, then builds the mathematical model based on Rotor rotating d, q coordinate system and finally elaborated the principle of permanent magnet synchronous motor vector control.(2) Some commonly used control scheme of PMSM Vector Control are introduced. The article selects id=0control and maximum torque per ampere control (MTPA) for in-depth study, the principle of the two control methods are analyzed theoretically. And duing to the difficultly of solving the the relationship between electromagnetic torque and d,q-axis current under MTPA control, an engineering approximation-curve fitting is given in order to solving the proplem. The article comparatively analyse of the fitted curve and the theoretical curve.(3) The simulation model of PMSM vector control under id=0control and maximum torque per ampere (MTPA) control based on MATLAB/Simulink are built and compared under motor running. The MTPA control under engineering approximation method is for detailed study. The article comparative analysis the motor operating status under the control of three times fitting polynomial and five times fitting polynomial.(4) The speed sensorless based on model reference adaptive (MARS) is researched. The MARS structure is designed in theory, adjustable model and speed identification model are built. Lastly, based on the MTPA control the simulation model, The speed sensorless model is used in the simulation system.The article comparative analysis the motor operating status under speedsenor or speedsensorless(5) Finally, the article summarizes the full-text work and the future work is discussed.