针对永磁同步电机(PMSM)全速域范围内无速度传感器运行时，电机低速起动位置估计困难的问题，提出了一种恒电流变频(I/F)和扩展卡尔曼滤波器(EKF)相结合的控制方法。在低速采用恒电流变频比起动，中高速切换为EKF进行位置和速度的估计。为解决切换过程不稳定的问题，利用电机转矩-功角自平衡特性，在切换过程中以两种控制方法给定的角度差作为反馈输入信号来减小切换前给定电流，在角度差接近零时切换电流和位置给定，使切换前后给定电流和给定位置基本保持不变。最后通过仿真验证该方法的可行性。

It is difficult to estimate the low-speed starting position of permanent magnet synchronous motor (PMSM) when there is no speed sensor in the full speed range. Aiming at the problem, a control method combining constant current frequency conversion (I/F) and extended Kalman filter (EKF) is presented. At low speed, the constant current variable frequency ratio is adopted for starting. At medium and high speed, the extended Kalman filter is switched to estimate the position and speed. In order to solve the problem of unstable switching process, the self-balancing characteristics of motor torque and power angle is used. In the switching process, the angle difference given by the two control methods is used as the feedback input signal to reduce the given current before switching. When the angle difference is close to zero, the given current and position are switched, so that the given current and given position remain basically unchanged before and after switching. Finally, the feasibility of this method is verified by simulation.

国家自然科学基金项目(51975433,51975430);湖北省自然科学基金项目（2018CFB144）