Permanent Magnet Synchronous Motor Vector Control System Of Flux-weakening Control Strategy Study

With the development of urbanization,city traffic become congestioned,a lot of environmental pollutions caused by automobile traffic.Subways,city-trains and electric vehicles have developed rapidly in recent year.The electric drive technology for vehicles has been getting more and more attention.PMSM is becoming a mainstream of electric drive system for their merits such as low power consumption,high power density,high efficiency and simple maintenance.For the permanent magnetic field can't be regulated after the permanent magnet material was magnetized,it is a challenge for the application of this type of motor in electric drive technology for vehicles,which requires constant power operation and wide speed region.This catches many researchers'eyes.This paper studies the flux weakening control strategy of PMSM,a control method of modifying the current setting is proposed.The method consists of two parts:one is the determination of the flux weakening region;another is the current setting modification.The flux weakening region is determined by the angle between the constant torque direction and the output of current regulator decreasing direction,the direction of voltage decreasing is calculated by using the gradient descent method.The current setting is modified by the direction of the variation of torque and voltage and the magnitude of the voltage error according to the flux weakening region.The control strategy has high control precision,fast response and robustness.Depend on the theory analysis of the flux weakening control strategy based on the gradient descent method,by dint of the STM32 experiment platform,the experiment of the flux weakening control of PMSM is built and the result is coincident with theory analysis,the experiment result verifies the validity and the feasibility of the control strategy,it has a good realization of speed expansion with flux wenkening.