ac motor vector transformation control

In 1971,the scholars have put forward the ac motor vector transformation control of new thoughts,new

theory and new technology,its emergence of ac motor control technology research is of epoch-making significance.Because of this through the field-oriented vector transformation of exchange closed loop control system,its control performance can be comparable with the dc system completely.Then,with the power electronics,microelectronics,computer technology and the development of permanent magnetic

material science,the vector control technology application and popularization rapidly.Vector control is in the unified theory of electromechanical energy conversion,motor and developed on the basis of space vector theory,it first used in three-phase induction motor,soon extended to three-phase permanent magnet synchronous motor.Due to the operation of the three-phase induction motor,the rotor heat causes the rotor parameters,and the rotor magnetic field observation depends on the rotor parameters,so the rotor magnetic field is difficult to accurate three phase induction motor observation,make the actual control effect is difficult to achieve the result of theoretical analysis,this is the deficiency of vector control in practice.

The permanent magnet synchronous motor with permanent magnet rotor,parameters are fixed,so the vector control of permanent magnet synchronous motor has been widely applied in low power and high precision.Then,in 1985 permanent magnet motors for saleby Germany ruhr university ockMr.Professor Depenbr first advanced the theory of direct torque control,and then turn it to weak magnetic speed range.Compared with vector control technology,the direct torque control is largely solve the characteristics of the three-phase induction motor vector control is affected by the motor parameters change the problem.Direct torque control was born,in his novel control thinking,system structure of simplicity,good static and dynamic performance has received the widespread attention and got rapid development.At present this technology has been successfully used in the high-power ac drive electric locomotive traction.Germany,Japan,the United States are racing to develop the new technology [3] [4].After the 1990 s,with the wholesalemotor.blogspot.com development of microelectronics and computer control technology,high speed,high integration,low cost and the commercialization of the advent of the microprocessor made it possible to fully digital ac servo system.

Through the microcomputer control,can make the motor speed control performance has greatly

improved,making complex vector control and direct torque control,greatly simplifies the

hardware,reduces the cost,improve the control precision,also can have protection,display,fault

monitoring and diagnosis,the debugging and the reset function.In addition,the change control

strategy,revision control parameters and model also becomes simple,thus greatly improve the

flexibility,reliability and practicability of the system.In recent years,in the advanced digital ac

servo system,many companies have introduced a special chip for motor control.Can quickly complete the system of speed loop,current loop and position loop fast precision adjustment and complex vector

control,to ensure the algorithm for motor control,such as direct torque control and vector

control,neural network control,can the completion of high speed and high precision.Nonlinear

decoupling control,adaptive control,artificial neural network model reference single phase capacitor start induction motor adaptive control,the control and the state

observer and linear quadratic integral control and fuzzy intelligent control and so on all kinds of

new control strategies are constantly emerging,show more III broad prospects.Therefore,the use of

high-performance digital signal processor intelligent digital ac permanent magnet servo control

system is one of the important development direction of ac servo system.