Study On Sensorless Direct Torque Control System Of Super High Speed PMSM Spindle

Along with the social production requirement enhances unceasingly, the kinds ofmotor also increase unceasingly, and motor control technology are constantly upgraded.In the PCB processing equipment industry, high spindle rotation speed can improve theprocessing quality to make a hole-site much smaller, so it leads the speed of spindlemotor to be continuously improved. Electric spindle is a kind of motor that is justdriven directly, permanent magnet synchronous electric spindle with ultra-high speedis driven directly by the high-speed permanent magnet synchronous motor(PMSM).PMSM had many advantages, such as high air gap density, small torque ripple,high efficiency and simple structure. It is widely used in the situation which requireshigh control accuracy and high reliability. Firstly, this paper analyzed the structure andthe features of PMSM. Then it set up the mathematical model and the motion equationof the PMSM in different coordinates.Based on the analysis, the summary of the existing theories and practices, thepaper introduced the conventional direct torque control(DTC) theory, and deeplydiscussed application of the DTC in PMSM. Based on this, it gave some controlstructure diagrams used DTC theory in the PMSM system. Used the MatLab/SimuLinktool box, it set up some simulation modules to the PMSM DTC systems, and realizedthe simulation experiment of the PMSM DTC control systems.Due to the use of traditional position or speed sensors, it reduced the reliability ofsystem, increased the system cost, and it is difficult to install in ultra-high speed motorshaft, so the sensorless algorithm is especially important. This article analyzedcharacteristics of the sliding mode variable structure, it introduced a kind of sensorlesssliding mode observer algorithm which based on variable structure control.Finally it designed the whole hardware structure of the system, and proposedsome detailed function circuits. Based on the hardware, it gave some software flowcharts, some software programs used by C language which realized some functions.