针对永磁同步电机(PMSM)系统速度环采用传统的PI控制时，无法兼顾转速超调量与响应快速性要求的问题，提出采用二自由度(2-DOF)PI控制策略设计速度环控制器。同时，为减小负载转矩、电机参数变化等扰动因素的影响，将其作为总扰动，利用扩张状态观测器(ESO)进行观测，并基于观测值进行前馈补偿。仿真结果表明，采用所设计的2-DOF PI控制，可以有效减小转速的超调量，提高转速的跟随性能和系统的抗扰动性能。采用基于ESO的2-DOF PI控制，进一步提高了系统的抗负载扰动性能，同时可以实现转速的快速响应和无超调控制。所提控制策略的正确性和有效性得到了验证。

When the traditional PI speed control strategy is adopted for permanent magnet synchronous motor (PMSM), the requirements of small overshoot and quick response cannot be balanced at the same time. In order to solve this problem, a control strategy based on two degrees of freedom (2-DOF) PI control is presented. In addition, the load torque changes, motor parameters variation and other disturbance factors are regarded as total disturbance of the system. A disturbance observer based on extended state observer (ESO) is designed to observe the total disturbance. The observed value is used for feed-forward compensation. Simulation results show that the speed overshoot can be reduced, the speed tracking performance and the system capacity of anti-load disturbance can be improved by the proposed 2-DOF PI control method. It is also demonstrated that the capacity of anti-load disturbance can be further improved by the proposed control strategy of 2-DOF PI control based on ESO. The system also has a fast response without speed overshoot. The validity and effectiveness of the proposed control strategy are verified.