Precision speed control of PMSM using disturbance observer and system parameter compensator

This paper presents external load disturbance compensation that uses deadbeat load torque observer and regulation of the compensation gain by parameter estimator. The response of permanent magnet synchronous motor (PMSM) follows that of the nominal plant. The load torque compensation method is composed of a deadbeat observer that is well-known method. However it has disadvantage such as a noise amplification effect. To reduce of the effect, the post-filter, which is implemented by MA process, is proposed. The parameter compensator with recursive least square method (RLSM) parameter estimator is suggested to increase the performance of the load torque observer and main controller. Although RLSM estimator is one of the most effective methods for online parameter identification, it is difficult to obtain unbiased result using itself only application. It is caused by disturbed dynamic model with external torque. The proposed RLSM estimator is combined with a high performance torque observer to resolve the problems. As a result, the proposed control system becomes a robust and precise system against the load torque and the parameter variation. A stability and usefulness, through the verified computer simulation and experiment, are shown in this paper.