Research Of Vector Control System For Controllable-flux Pmsm Using Rotor Flux Linkage Observer

In the traditional permanent magnet synchronous motor (PMSM) , it is difficult to change the permanent magnet (PM) flux linkage which results in the hardness of rising motor speed above rated value by PM-flux linkage weakening. Internal composite-rotor controllable-flux PMSM which makes full use of the advantages of NbFeB permanent magnet and AlNiCo permanent magnet is presented, NbFeB PM has high remanent flux density as well as coercive force ,while AlNiCo PM has high flux density but low coercive force. With no increasing the inverter power, applying the armature magnetomotive force of stator current i_d pulse, the magnetizing intensity and direction of AlNiCo are controllable,which make the air-gap flux created by NdFeB is controllable, so that the PMSM can operate in a wi_de speed. It is to certify the designed memory motor reasonable and feasible through model machine test.In this paper, the principle of Interior Composite-Rotor Controllable-Flux PMSM is researched and analyzed in detail. Under normal circumstances, the i_d=0 vector control strategy is adopted. When the flux of the rotor will be adjusted,the current iq will be set to zero by flux logical controller, and an impulse of the given current i_d will be created in the stator windings.By imposing a d-axis current pulse whose direction and amplitude can be controlled, the magnetic flux of rotor magnet has changed and it achieved the weakness of magnetism. After magnetization, the machine returns to steady operation with the i_d =0.According to the Controllable-Flux character of the machine, it is necessary to design a rotor flux observer which will estimate the rotor flux linkage. In this paper, two ways are introduced, self-adaptive observer and flux linkage which based on Extended Kalman Filter. Because the variety of the current and the magnetic field will change tempestuously in the machine, the normal PI regulator can not adapt the process quickly. A parameter self-adjusting speed controller is designed. Simulation model of the motor vector control system is built in MATLAB/Simulink. The proposed vector control system using rotor flux linkage observer is proved viable by the simulation results. The vector control system of internal composite-rotor controllable-flux PMSM has favorable static and dynamic characteristics.