Disturbance compensating control of direct-drive PMSM speed servo systems based on the synchronous measurement method

The noise resulted from speed measurement greatly influence on the performance of disturbance compensation control. For the high accuracy speed servo system of direct-drive permanent magnet synchronous motors, a disturbance compensating control based on the synchronous measurement method was developed. The synchronous measurement speed signal has a high resolution and a fluctuant measurement time. By taking it as input to the disturbance observer, the effect of the speed noise on disturbance torque observation can be reduced. Meanwhile, a modification to synchronize the calculation of the extended state observer with synchronous-measurement speed signals was investigated, and the performance of disturbance compensating control was further improved. The proposed method has good robustness, and is easy to be implemented. The experimental results prove its effectiveness in reducing speed noise and improving disturbance compensating performances.