Research On Flux-weakening Control Of PMSM Based On Single Current Regulator With Variable Q-axis Voltage

Permanent Magnet Synchronous Motor (PMSM) has the advantages of simple structure, high efficiency and widely applied in various fields. Flux-weakening control is needed for a wide speed range operation.According to the mathematical model of PMSM in the two-phase rotating coordinate system, the flux-weakening operation region is analyzed in this thesis, getting the dynamic regulatory regions of current while flux-weakening control and the steady-state optimal operating point. By analysis of the flux-weakening control based on single current regulator with fixed q-axis voltage, it has the advantages of easy to implement, fast dynamic response, and high robustness. But the efficiency and load capacity of motor are declined. The reason is that the DC voltage of inverter is not fully utilized and the steady-state operating point is located in the voltage ellipse. The thesis presents a new method of given q-axis voltage, named flux-weakening control based on single current regulator with variable q-axis voltage. This new flux-weakening control strategy can fully utilize the input voltage and make the motor working in the optimal operating point on the basis of maintaining the original advantages. The efficiency and load capacity of motor are improved obviously.Setting up a simulation model of drive system of PMSM and an experimental platform based on Myway system, the simulation and experiment results using this flux-weakening control method based on single current regulator with variable q-axis voltage show a high dynamic performance. Furthermore, the input voltage of PMSM is fully utilized and the motor steady-state operating point is the optimal one. The efficiency and load capacity of motor are improved and the drive system gets wide speed range.