Research On Sliding Mode Variable Structure For Permanent Magnet Synchronous Motor Control

Permanent Magnet Synchronous Motor (PMSM) has the advantages of highmagnet density, small torque pulse, big torque-inertia ratio, high efficiency, simpleconstruct and so on. PMSM has been applied to the occasions that require highcontrol precision and high reliability far and wide, such as numerical controlmachine tool, radar and some military weapons, robot and so on. In addition, itplays an important part of AC motors in modern times.Sliding-mode variable structure control which sliding mode can be designed isinsensitive to system parameters change and load disturbance, and has theadvantages of good robustness, quick response, easy realization and so on.Accordingly, a control strategy of high quality will be obtained by applying slidingmode control to the control of PMSM servo system. Thus, this paper mainlyresearches the application of SMC to PMSM control.Firstly, based on the detailed analysis on the mathematical model of PMSM,this paper gives the linear decoupling state equation of PMSM in the d-qcoordinates by combining with Vector control technique. Then the simulationmodel of PMSM servo system is built with Matlab/Simulink by using rotor positionoriented control scheme of Vector control.And then, with the combination of the merits of SMC and fuzzy control, thispaper designs the sliding mode controller based on fuzzy self-adjusting of switchgain for PMSM speed control, and accomplished S-function realization of thiscontroller algorithm. For this controller, the switch gain of SMC is adjusted in realtime by using fuzzy logic, so it not only has the characteristics of SMC which areinsensitive to parameters change and disturbance, but also has the ability of fuzzyself-adjusting, thereby the aim of decreasing chattering can be achieved.