Research On Field-weakening Control Methods Of Permanent Magnet Synchronous Motor

With deeply researching and using the permanent magnetic material, the performanceindex of the power electronics device continuously improving, as well as the controlalgorithm of motor drive system is more and more mature, the application field of permanentmagnet synchronous motor is wider and wider, which also has a higher and higher demandabout the wide range running of the motor speed control system. However, conventionalcontrol method can’t make the motor run above the rated speed, therefore, broadening themotor speed range is a problem to be solved.Weak magnetic control of permanent magnet synchronous motor can make the motor runabove the rated speed, and broaden the speed range of the motor. So, this paper introduce thetheory of the permanent magnet synchronous motor in detail, and then deeply researched theweak magnetic control strategy based on voltage feedback of the permanent magnetsynchronous motor, and finally, do simulating for the design system with the softwareMatlab/Simulink, analysis the simulation results to verify the feasibility of the weak magneticcontrol strategy. The specific are as followings:First, have established the important dynamic model of permanent magnet synchronousmotor in rotating coordinate system, and then analyzed the weak magnetic control principle ofpermanent magnet synchronous motor and introduced constraint conditions of the weakmagnetic control, the given current of the control range of the weak magnetic control in detail,and then made a simple introduction of the existing various weak magnetic control algorithms,of course, every control algorithm has its own advantages and disadvantages. Then, havededuced the current vector’s running tracks when the motor run during the constant torque orthe weak magnetic control internal, and also given the relevant instructions.Then, have constructed the weak magnetic control system block diagram of permanentmagnet synchronous motor based on voltage feedback, which is based on the SVPWMmodulation algorithm, and then have designedthe key modules. After modeling andsimulating the whole control system with Matlab/Simulink, verified the feasibility of theweak magnetic algorithm by the simulation results on the theoretical level. Last, by the resultsof simulation analysis points out the shortage of the weak magnetic control strategy, so as topropose the idea to make the weak magnetic control strategy more perfect.