Position control of a LBDCM drive

In this paper, the dynamic model estimation and quantitative position control of a linear brushless DC motor (LBDCM) drive are studied. First, the inverter-fed LBDCM drive is established and its dynamic model is estimated from measurements. Then, according to the estimated model at nominal case, a two-degree-of-freedom controller (2DOFC) is designed to meet the prescribed tracking and load regulation position control responses. As the system parameter and operating condition changes occur, an output feedback linear model following controller (MFC) is added to reduce the effects of perturbations, and hence the performance degradation can be reduced. Finally, a ramp position command with suitable changing rate is generated to avoid the occurrence of velocity limitation, and thus the overshoot of position response due to large-step command change can be eliminated.