Research On Sensorless Control Of PMSM Based On MRAS

Permanent magnet synchronous m otor (PMSM) has m any excellentperformances, with high precision control method, it is widely used in industry, sociallife, aerospace, national defense and other fields increasingly. This paper reviewescontrol methods of AC motor briefly, such as variable voltage and variable frequencycontrol, vector control(VC), direct torque control(DTC). And this paper focuses on thesuperiority of the direct torque control method.Both direct torque control and vector control require the detection of rotorposition and speed, the speed control system of traditional motor is completed by themechanical sensor such as photoelectric encoder. Speed sensor increases the cost ofthe system and the difficulty of installation and maintenance, meantime, it reduces thereliability of the system. At the sam e time, the application of speed sensor is a lsolimited in m any harsh condition s such as high tem perature and high hum idity.Therefore, PMSM sensorless con trol is gradually concerned by many scholars andresearchers.Direct torque control with senorless control based on Model Reference AdaptiveSystem (MRAS) is studied in this pape r. A permanent magnet synchronous motor isseemed as the control object, instantaneous reactive power is applied to identify therotor speed, the m ethod has som e advantages such as sim ple formula, sim plecalculation, without stator resistance and so on, and it is pr oved theoretically that thespeed estimation with the instantan eous reactive power MRAS speed identificationhas a good perform ance. On the basis of th eoretical analysis, a sim ulation model ofthe system is established in MATLAB/Simulink, the simulation result is obtained, andis compared with the theoretical analysis.Based on MATLAB/Sim ulink, experimental verification is com pleted in thispaper. DSP (TMS320F2812) as control co re and MOSFET (IRF450) as switchingdevice are used, algorithm is studied. Based on the C/C++, MRAS observer design isfulfiled, and applied in PMSM-DTC system. With the tracking performance analysisin the three operating conditions, the feasibility of the method is preliminary proved.