Research On Flux Weakening Control Of Disturbance Rejection For Permanent Magnet Synchronous Motor

Permanent magnet synchronous motor(PMSM)is becoming the the electric drive core of new energy vehicles for its merits such as low power consumption,high efficiency and high power density.With the rapid development of new energy vehicles,in order to meet the requirements of large power and wide speed range of electric drive technology,the flux weakening control strategy has become one of the research focuses in permanent magnet synchronous motor(PMSM)speed regulating system.At first,the basic principle of flux weakening control and various weak-flux control strategies are introduced in this paper,especially the realization of field-weakening control based on voltage regulation method and signle current regulator method.With the increase of the motor speed and current,effects of cross-coupling between the d-axis and q-axis strengthened,the decoupling control is need to control the current loop independently.As the perfermance of decoupling control in conventional current regulator depends on the electrical parameters of PMSM,and the inaccurate nominal value or perturbation of the parameters will weaken the decoupling effect,and even affect the stability of motor system.In this paper,a model reference adaptive identification algorithm is designed to accurately identify the electrical parameters of the motor.Combining with the decoupling control method,exact decoupling control of the current loop is realized to improve the dynamic performance of the current loop in PMSM.Secondly,according to the idea of disturbance estimation and attenuation control strategy,the cross-coupling and the parametric uncertainties in the nominal model of PMSM are equivalent to lumped disturbance of system.A finite-time disturbance observer is designed to estimate the lumped disturbance,reject the system disturbance by feedforward compensation.The proposed decoupling control method can not only eliminate the coupling effect on the current response performance,but also suppress the system uncertainty and external interference.In the end,simulations and experiments are carried out to verify feasibility and effectiveness of the exact decoupling control of the current loop based on parameter identification and the current loop decoupling control based on finite time disturbance observer.