| Induction motor has so many connatural advantages, such as the structure issimple,the volume is small, the speed is high, the material is durable, the capacity is high.For all these reason the induction motor speed control technology get more and moreattention of people. Especially, when the computers and the rapid development ofelectronic technology have advanced recently, many advanced control strategies haveemerged to promote the rapid development of AC variable speed system. Vector control isthe main method among the advanced control strategies, which greatly improves thedynamic performance of AC drive system. The research on Vector Control System hasbecome an important research in the induction motor speed control system.In the traditional vector control system, the speed is usually obtained by the speedsensor. But these sensors are easily affected by the environment, which limits the scope ofthe application of the control system. Therefore, the study of speed sensor technologybecomes to be one of the most important issue of induction motor vector control system.This paper first introduces the research status of the vector control with speed sensortechnology and parameter identification technology in the induction motor vector controlsystem. Then this paper briefly describes the current main methods widely used in theworld, and compares the advantages and disadvantages of each method.This paper briefly describes the basic principles of vector control algorithm. It makesthe effect of the induction motor control like the DC motor control by conversion ofcoordinates; introduce the mathematical models of induction motor in the three-phasecoordinate system, two-phase stationary coordinate system and two-phase rotatingcoordinate system; introduce the basic idea of voltage space vector modulation, and builda voltage space vector module; introduce induction motor vector control program, whichdo a detailed theoretical preparation for building the model of the induction motor vectorcontrol algorithm.In this paper speed sensor is added to the basic system for improving the dynamicproperty of the induction motor vector control system, which identify the speed using themodel reference adaptive system; at the same time Popov stability theorem verifies thestability of the system. On the basis of the speed identification algorithm, this paperapplies the sliding mode controller replacing the PI controller, which enhances therobustness of the system. Sliding mode control method has its drawbacks so that thispaper use the method of reaching law to hold-up the jitter problem.In the induction motor vector control system, temperature change and skin effect willlead to the change of resistance, at the same time the change of resistance will led to theinaccuracy of magnetic field orientation, then affect the performance of the vector control system. Therefore, the exact resistor limits the performance of vector control system. Inorder to improve the control precision of the vector control system, the resistance must beidentified in real time and accurately. In this paper, use the full-order state observer toidentify the motor parameter; and the stability of the system is verified by the Lyapunovtheorem of stability. In this paper, this method effectively identified the rotor resistanceand stator resistance. The simulation results show that the method is feasible.Finally, this paper use the software of Matlab/Simulink to build the traditional modelof the vector control system. On the basis of this, one hand built the speed identificationmodule, the analysis of the simulation tell that the system can quickly track speed and ithas a good dynamic performance; on the other hand build the identification simulationmodel of rotor resistance and stator resistance, the analysis of the simulation tell that itcan accurately identify the resistance and this algorithm is feasible, the system has a gooddynamic performance. |
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