A new generalized predictive controller for the speed control of PMBLDC motor

Usually speed and position of a permanent magnet brushless direct current motor (PMBLDCM) rotor is controlled in a conventional cascade structure. The inner current control loop runs at a larger bandwidth than the outer speed control loop to achieve an effective cascade control. This paper proposes a multirate based general predictive control (GPC) law performed for the conventional cascaded PI-PI scheme. Both speed and torque tracking objectives are achieved in matched and mismatched parameter case. The measured and unmeasured disturbances can be effectively rejected and the motor can run at desired speed at constant load. In addition, non-minimum phase characteristics and system constrains can effectively be handled by proposed GPC algorithm. The simulation results are provided to show that the proposed GPC strategy results in better performance than that of the conventional well tuned cascade PI- PI control strategy. The proposed controller has also been implemented to control the speed of a PMBLDCM and the results show an improvement over conventional scheme.