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Research On Adaptive Control Scheme Of The Speed Sessorless Induction Motor Drives

Posted on:2013-08-31Degree:MasterType:Thesis
Country:ChinaCandidate:L C YuFull Text:PDF
GTID:2252330392468171Subject:Power electronics and electric drive
Abstract/Summary:PDF Full Text Request
Vector Control has a wide speed range, low-frequency great torque and fastdynamic response, because of the above-mentioned advantages it is widely used inAC drive technology. Need for speed closed-loop control in the vector control,however, the high price of speed sensor improves the cost of the transmissionsystem and speed sensor is not easy to maintain. Speed sensorless vector control iswell to avoid these, it applies to some place where the speed control accuracy is nothigh, at present speed sensorless vector control has been widely used in commercialinverter. In speed sensorless vector control, flux and speed estimation processinvolves the motor parameters, changes in motor parameters will have an impact onthe control performance, so motor parameters identification is very important. Inaddition, the speed loop in vector control also has a great influence on the speedcontrol system, a simple PI control is difficult to meet the speed tracking ability andload regulation ability two aspects of performance requirements. The paper willfocus on speed estimation, motor parameters online identification and the speed loopdesign three aspects in speed sensorless vector control to improve the performanceof the control system.First of all, for the speed sensorless vector control, using the model referenceadaptive system (MRAS) which is based on mathematical model of induction motorin the rotating coordinate system model to estimate the speed of the motor. In orderto avoid the influence on the speed and flux estimated caused by the changes inmotor parameters, this paper designs a stator resistance online identificationprogram. The effectiveness of speed estimation and stator resistance onlineidentification scheme is verified through the MATLAB simulation and systemexperiment.Secondly, for the speed loop design problem of vector control, this paper focus onthe speed loop compensation and speed controller design two aspects. Based on thespeed loop mathematical model of vector control the paper designs a load observerand its output is used for the torque feedforward control. Designed a sliding modevariable structure speed controller based on sliding mode control theory andmathematical models of induction motor. The effectiveness of torque feedforwardcontrol and sliding mode variable structure speed controller is verified through theMATLAB simulation and system experiment.Finally, experiment on the7.5kW induction motor experimental platform which isbased on the ARM controller, the speed estimated, stator resistance onlineidentification and speed loop design scheme is used in the experiment platform. Experiment verifies good speed performance of speed sensorless vector controlsystem, the rapidness and precision of the stator resistance online identificationscheme and the effectiveness of speed loop design method.
Keywords/Search Tags:Induction Motor, Speed Sensorless Vector Control, Speed Estimation, Online Parameter Identification, Speed Loop Design
PDF Full Text Request
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