Sensorless Control Of Permanent Magnet Synchronous Motor

In the traditional permanent magnet synchronous motor motion control system,mechanical sensors need to be installed on the motor rotor to obtain the motor rotorinformation in order to improve the control precision. But the use of these sensors will cause alot of inevitable disadvantages:(1) the size of motor and its rotor inertia will increase becauseof mechanical sensor;(2) mechanical sensor will be limited to the working environment,sothat the transmission system can’t be used in certain bad environment;(3) some high precisionmechanical sensor and its additional circuit not only increases the cost but also reduces theanti-interference and reliability of the system.In order to solve those problems, motor sensorless control has become an importantdirection of speed control system research. Based on model reference adaptive theory and thetheory of least squares, a sensorless control algorithm was derived, the main content ofresearch includes the following aspects:First, build the mathematical model of permanent magnet synchronous motor; derive themathematical model of permanent magnet synchronous motor in different coordinate systemby the principle of coordinate transformation, with the methods of vector control; Set uppermanent magnet synchronous motor double closed loop vector control system model andsimulation.Secondly, according to the basic principle of model reference adaptive theory and thepermanent magnet synchronous motor in the two-phase synchronous rotating coordinatessystem, mathematical model is deduced based on model reference adaptive motor speedestimation equation, and set up a permanent magnet synchronous motor sensorless vectorcontrol simulation model based on model reference adaptive theory, simulation results verifythe validity of the algorithm in theory. For the problem of adaptive law parameters, fuzzycontrol theory is indroduced to improve the performance of model reference adaptiveestimation of rotating speed, and a simulation was carried out.Third, according to the basic principle of least squares method and the mathematicalmodel of permanent magnet synchronous motor, motor speed estimation equation based onthe least squares method was deduced, and set up a simulation model based on the leastsquare method of sensorless permanent magnet synchronous motor vector control, simulationresults show the algorithm is correct in theory, provides theoretical basis for practicalapplications. Fourth, combine the model reference adaptive with least square method, a new type ofmotor rotor speed and position estimation algorithm is deduced, the simulation shows that thealgorithm runs at high or low speed has good dynamic and steady performance.Finally, the full text of the work is summarized, points out the deficiencies and furtherimprovement.