Built-in Permanent Magnet Synchronous Motor Field Weakening Control Based On UDE

Interior permanent magnet synchronous motor(IPMSM)has the advantages of simple structure,reliable operation and high power density.Also it can improve the torque output capacity by using reluctance torque and enlarge the speed range.So it is widely used in electric vehicle drives and other occasions.The flux-weakening control is usually adopted to expand the operating range of the high speed region.It is great significance for efficient and stable operation to improve the robust of flux-weakening control.The flux-weakening control for IPMSM is studied in this thesis based on the vector control.The model parameters of the controller mismatch the actual operating parameters because of variation of motor parameters when the motor runs on the flux weakening.The traditional flux-weakening based on formula calculation method will reduce the control performance of the system.At the same time,the current and torque fluctuate greatly when the motor is switched at a fixed speed between the constant torque region and the weak magnetic region.An improved uncertainty and disturbance estimator(UDE)-based flux-weakening control strategy for IPMSM is proposed based on UDE-based control.The UDE-based control is introduced in the control system of IPMSM.The robustness in the flux weakening region is enhanced by appropriate reference model,control law and improved parameter tuning method based on the characteristics of current following in flux weakening region.The flux-weakening adjusting factor is put forward by analyzing the flux-weakening switching point and establishing 3D table.The online control of flux-weakening adjusting factor is realized by lookup table and the switching fluctuation between the constant torque region and the flux weakening region is reduced.The simulation and experiment platform for 20kW interior permanent magnet synchronous motor are built to verify the validity of the improved UDE-based flux-weakening control strategy for IPMSM.Simulation and experimental results show that the proposed control strategy can effectively reduce the current and torque ripples in the flux weakening region,and achieve smooth switching between the constant torque region and the flux weakening region.The proposed control strategy can still effectively suppress the current and torque ripples in the flux weakening region and improve the robustness of the control system when the model parameters of the controller is mismatched with the actual operating parameters.